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Manager - AB7RG
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Benchmarks

Created by on 2007-02-22
Benchmarks

Benchmarks

A benchmark is a point of reference that we measure or compare other things against. They crop up in our daily lives without much notice. For example, your neighbor buys a new vehicle, and you go over to take a look. One of the first questions asked will be, how much horsepower does it have? Almost no one asks how heavy the vehicle is, or how much torque the engine has, even though these figures are more of a benchmark of performance than horsepower alone.

Let's put this in a different perspective. Horsepower (in basic terms) is a function of torque times the rotational speed (rpm) of the engine we're measuring. A high-revving sports car engine might achieve the same horsepower as a low-revving diesel engine, however, the real difference between them is in the amount of torque each one delivers. In other words, horsepower alone won't tell us much.

The decision to buy a diesel-powered pickup truck, or a sports car, depends on whether you need to haul a load, or haul fast! It's perhaps doubtful if we need either vehicle, but one thing is for certain, every single amateur radio station has to have an antenna system. They too have benchmarks to measure their respective parameters.

One of the anecdotal standards for how well they work has become the SWR reading the antenna exhibits. That is to say, the lower the better. The fact is, the SWR reading is no more a benchmark of performance for an antenna, than horsepower is to a vehicle. Without taking the other factors into account, it's just a number.

Another common reference is the number of DX stations that have been logged using said antenna. Without taking band conditions and other facts into account, it's just a number.

Antennas are often selected using only their gain rating, usually expressed in dB. The question is, dB what? The decibel is a power ratio which must be compared to a known benchmark. The two most common amateur-related ones are dBi, and dBd. In other words, the gain rating is compared to either an isotropic source, or to a dipole source, respectfully. Without that identifier at the end of the ratio, using gain as a means of comparison means nothing. Again, it's just a number.

To put a finer point on it, the dB is based on a logarithmic scale. For example, doubling your power output (500 watts to say 1,000 watts) results in a 3 dB increase in signal strength; a barely discernible increase on the receiving end. This fact makes it hard to understand why some amateurs strive to get an extra 50 watts out of their amplifiers by overdriving them. By the way, an extra 50 watts out of a nominal 500 watt amplifier represents an imperceptible .4 dB increase in signal strength.

An antenna system can exhibit a huge overall loss as well, but no one seems to care as long as they can make contacts. Here's an example. Mounting a 1/4 wave vertical on a pipe stuck in the ground without radials under it. The amount of power lost to heating the earth around it depends on several factors, but might be as much as 30 dB, perhaps more. If there is a benchmark, it's the same vertical with about 100 radials under it. While we all don't have the luxury of installing 100 radials, the difference is astounding! It's certainly more effective than adding an amplifier for several reasons.

Yet another often-heard statement is, I can work anything I can hear. Can you now? The fact is (contrary to popular belief), antennas are NOT reciprocal in their transmit verses receive performance. Therefore, it is nave to assume you can hear every station that can hear you, or visa versa. Unfortunately, this myth continues to be propagated (excuse the pun) by otherwise knowledgable people.

The proliferation of antenna tuners and couplers speaks volumes. Seemingly, it's no longer necessary (or desirable as the case may be) to erect resonant antennas. With the tweak of a knob or two, it's possible to load up just about any chunk of metal and turn it into an antenna. Improbable as it may sound, some antenna tuners can be tuned up without an antenna connected! There are two hidden factors at play which most users miss.

The most common tuner configuration is the T network. It consists of two series capacitors (one each on the input and output), and a shunt inductor between them. The advantage over other designs like a Pi network is, the values of the capacitors can be much smaller in value (usually around 500 pF). Improperly tune them, add in a very high SWR impressed on the feed line, and it is not inconceivable for 90% on the input power being used to heat up the various parts. If you use one of these tuners, remember this simple rule; adjust the capacitors for the largest amount of capacitance consistent with a good match. If one or both of the caps are almost un-meshed, you haven't done it correctly, or the tuner is at the extreme edge of its matching capabilities. Either condition results in excessive losses.

What's more, the ability to match an antenna with a tuner means very little except that the tuner works. Some very popular antennas (a G5RV for example) can easily be made into an all band antenna with a tuner. What's missed is how well the antenna system is performing (remember, the tuner is part of the system). In too many cases the overall losses are more than the radiated power, and the radiation lobes are straight up! While you might be able to work everything you can hear, you're missing much more than you realize.

About this time you might be thinking antennas, sports cars, and diesel pickup trucks don't have much in common. Well they do, because their suitability for any given purpose is based on need. The one thing you can't do is turn one into another and maintain efficiency. For example, you might be able to haul a couple of bar stools in your sports car, and you might be able to enter a gymkhana with your diesel pickup truck, but the fact remains you wouldn't be using them to their best advantage.

Alan, KBG
www.k0bg.com
N4SL2007-03-09
RE: Benchmarks
At this point, it's no longer fun watching the 'tard flail.
Reply to a comment by : W4LGH on 2007-03-09

Mike W4EF...I agress with what you are saying. I agree that balanced line has a lot less loss than un-balanced. But I still contend that it is very hard to keep balanced line balanced from the shack to the antenna, due to outside influences. Once out of balance, it will radiate. This is one of the reasons they invented coax was to stop these outside influences. most communications engineers will agree the loss of the coax is easier to deal with than trying to keep a balanced line balanced. Bird droppings, the salt, especially here in Florida, and many other factors will change this, even simple rain, much less ice and snow will change it. As for the tuner at the antenna, I am certainly not talking about you typical shack tuner. I am talking about loading coils for this tuning. This will in effect make the antenna electrically resonant. An example here would be a screwdriver antenna with a 48" whip. The screwdriver has an adjustable loading coil to tune the antenna into resonance. Now take the same 48" whip and hook it to your shack tuner, it will make it see a 50ohm load, but you can't possible expect it to work as well as the screwdriver. I guess, maybe, the confusion has been in the defination of tunnig your antenna. If you want to define that as matching the impedance of your antenna system at the back of your radio for max energy transfer...so be it, but if you think you are tuning your antenna into resonance to get max energy transfer, you are only fooling yourself. I have made many tests myself, using 1/2 wave resonant antennas, and many non-resonant multi-band antennas, and the results have always been the same. The antennas were configured the same heights and directions, and the tests were done in a full 360 degree circle. The results always showed 1 to 2 S-units higher on receive, which can be any where between 4db to 12db more signal, which WILL make a difference on receiving someone or NOT. On the transmit side the signal was any where between 3db to 6db stronger. Again a fair amount of difference. Again these were tests that I actually did, and the results were actual, not something read out of a book. AND I am not saying don't read books, but don't accept everything you read as 100% hardcore FACT. The laws of physics haven't and won't change, but there have been many improvements with test equipment, and actual test proceedures that have changed many of the earlier finding. Everyone would have argued with you 30 years ago if you told them you could talk around the world on 1.8Ghz w/.6watt of power, but we are doing it today. Yes it takes lots of repeaters, but effectively from your 6/10th watt cell phone you can talk anywhere in the world, and ANY time. 30 yer ago everyone would tell you that 1.8ghz was strictly point to point and needed large parabolic antennas. Was that not a FACT then, yes, is it a fact now, NO! Did the laws of physics change...NO! Technology changed! No one has written anything NEW about ham radio in over 30 years. But the rest of the communications industry has many publications out, new testing proceedures, new equipment to actually show results.. But seriously, I have grown very tired of trying to lead this horse to water, he just won't drink. 73 de W4LGH - Alan
Reply to a comment by : W4EF on 2007-03-08

W4LGH wrote: >>With all the info that has bene passed back and forth, I still maintain that an antenna tuner hooked to coax (unbalanced line) is absurd, as you are doing NOTHING to the antenna itself, you may be tuning the entire antenna system, but NOT the part that is doing the most good. Move the tuner out to the antenna, now you are actually loading the antenna into resonance.<< There is no difference between the two cases above, Alan. In each case, all you are doing is impedance matching. Neither method modifies shape of the current distribution on the antenna. The latter (matching at the antenna) is only desireable to the extent that it minimizes feedline loss. True antenna "loading" actually modifies the shape of the current distribution along the radiator. This is why lumped element center inductive loading or distributed capacitive end-loading (i.e. capacity hat) are superior to base loading which is really nothing more than glorified impedance matching. When I load my 45' 160 meter vertical with a combination of center inductive loading and top-hat wires, I am actually improving the current distribution (making it more uniform). This raises the radiation resistance of the antenna relative to the ground losses thereby making the antenna more efficient that it would be if I just impedance matched the unloaded 45' radiator at the base. >>At this point I am not sure that using balanced line to an inside tuner is really good. It may work for you, because of low loss, and I still think the balanced wire or at least its resistance is becoming part of the antenna, and you are in effect tuning it into the overall picture.<< If the balanced feedline is close to the ground or nearby metal objects, you don't want it to be "tuned into the overall picture" at least in the sense that you don't want it radiating. You want it to carry energy to the antenna. If the open-wire feeder couples into the ground or nearby metal object it could actually end up being more lossy than coaxial line. There are instances where you want the feedline to radiate, as in the case of using a dipole fed against ground as a "T" or Marconi, but in that case you intentionally force all the feedline current to be "common mode". >> A good test would be to disconnect it from the antenna outside, short the end, its still balanced, and load it up on your tuner. I think you will be surprised at what you will hear, see and who you can talk to! You can also try the same with your coax, be it RG8X or 7/8" hard line, short the end at the antenna, load it up. If you have one of these super tuners it will probably load, but you won't hear much, much less do any talking. Easy tests, and will PROVE beyond a doubt! Try it sometime. << As I said before the fact that the balanced line may radiate more doesn't mean that it's a good thing. Feedline radiation is usually undesireable. If I go to the trouble of getting an antenna 100 feet high, I don't want the portion of the feedline that is 10 feet off the ground radiating. I may not even want the portion of the feedline that is 100 feet off the ground radiating if it screws up the radiation pattern. 73, Mike W4EF (from Eastern Ohio where nothing useful was ever invented)................
Reply to a comment by : W4LGH on 2007-03-08

YEP! I said I wouldn't but now I know..Its the "New Jersey Attitude". Man if Jersey is so damn GREAT, why the hell do they keep moving down here to Florida? Then try to make it like Jersey? Just stay up there and KEEP it all to yourselves! Ok..now its all yours. Tear it up boy!
Reply to a comment by : KD2BD on 2007-03-08

W4GLH (??) wrote: > or maybe its just your New Jersey attitude.. It's the same "New Jersey Attitude" that brought you the light bulb, the phonograph, the motion picture, the discovery of the Edison Effect (which lead to the invention of the vacuum tube), the transistor, the world's first electric power distribution system, the C and C++ programming languages, the Unix operating system, the radio work of Sarnoff and Marconi, the physics work of Einstein, the world's first FM radio broadcasts by Major Armstrong, and the world's first EME contact from my current home town. > But.... > You said..."A quarter-wave vertical is NOT an > isotropic source. A quarter-wave vertical has the > same directivity, gain, and capture area of a > half-wave dipole. Mankind has yet to build an > isotropic antenna. It is simply a theoretical > reference." > > If you think a 1/4vertical and a 1/2wave vertical > are the same, you need to go back and do some > studing! Maybe reading classes... I stand by what I said (and you quoted): A quarter-wave VERTICAL has the same directivity, gain, and capture area of a half-wave DIPOLE. > You got to keep apples with apples dude. Thanks for the advice. I'll try to do that next time. > Its truely amasing how people read what they want > into something and not what it says. I agree. It *IS* amazing... And thank you for demonstrating yet another perfect example.
Reply to a comment by : KD2BD on 2007-03-08

> So my questione here is..if you already have one in > your radio/amp whatever, why ADD a 2nd one to the mix? Because multi-band antennas provide absolutely no discrimination against harmonic radiation. A tuner in-line with a multi-band antenna helps ensure the antenna in use is resonant ONLY on the band of interest, not on all the other bands as well. As such, its use is simply a wise application of good engineering practice (FCC Part 97.101). 73, de John, KD2BD
Reply to a comment by : KD2BD on 2007-03-08

> Let's use a 1/4wave vertical as an example. Theory > tells us that when energy is applied it should > produce a perfect 360degree ball. We know this > isn't totally true because of outside influences, > but theory say this, its the isotropic antenna > effect. "Theory" doesn't say this at all! A quarter-wave vertical is NOT an isotropic source. A quarter-wave vertical has the same directivity, gain, and capture area of a half-wave dipole. Mankind has yet to build an isotropic antenna. It is simply a theoretical reference. Even an infinitesimally small dipole exhibits directivity and a gain of 1.76 dBi, just 0.38 dB below that of a full-sized, half-wave dipole. 73, de John, KD2BD
Reply to a comment by : MLMAN_EE on 2007-03-08

>K9IUQ >If bigger was not better we would all be using a >rubber duck to transmit on hf. Another brilliant statement. Bigger is NOT always better! Anytime you build an antenna to produce "gain" you are robbing Peter to pay Paul, as the ONLY way an antenna can show any gain is to direct more energy into a given direction. Let's use a 1/4wave vertical as an example. Theory tells us that when energy is applied it should produce a perfect 360degree ball. We know this isn't totally true because of outside influences, but theory say this, its the isotropic antenna effect. now you go to a 1/2wave vertical, and you compress this ball down expanding the outer edges, thus your 2.1db of gain. now you go to a 5/8wave and you compress this ball down some more, now producing 3db of gain, but your radiation pattern has changed, probably not going to effect vhf signals, but with hf signals you have lowered your take off angle, thus making larger hops during skip probagation. this might give you a super signal in Europe, but you might find you can't work a guy 500miles away. Bigger is NOT better, and one should have several antennas to do different things. NO ONE ANTENNA WILL DO IT ALL!! Although the StepIR comes pretty damn close. but then we won't go into resonant antennas again, our experts on here don't like them, they rather use lossy devices. ab8sw bill
Reply to a comment by : W4EF on 2007-03-07

K9IUQ wrote: >>No argument about the above statement. The argument is a 130ft wire with open feeders will radiate better than a 32 ft coax fed dipole (or trapped dipole) on 20 mtrs.<< Ok, I see what you are driving at, Stan. I should have read your post more carefully. I stand by what I wrote, however, at least in terms of efficiency of radiation (power entering coax vs. power radiated by antenna into space). What you are talking about with the 130 foot open-wire antenna is directivity. Directivity is a "rob Peter to pay Paul" zero-sum-game phenomenon. The 130ft long antenna open wire fed antenna will have significantly more gain on 20 meters than the trap dipole, but mainly because it has significantly greater directivity, not because it has better efficiency. Gain is as Martha would say "a good thing" but only if it occurs in a desireable direction. Since directivity is "robbing Peter to pay Paul", you will be worse off in some directions with the 130ft open-wire fed antenna than with the trapped dipole. Maybe this is okay (say you want to keep a schedule and you point the lobe of the 130ft antenna at the person you have your schedule with), but for that reason it's important to make the distinction between efficiency improvements (net improvement in all directions) versus directivity improvements (net improvement in one direction(s) with an equal net penalty in some other direction(s)). 73, Mike W4EF.....................
Reply to a comment by : K9IUQ on 2007-03-07

W4EF says MILF_MAN is right in this case. A trapped dipole is most efficient on the highest band of operation since at that frequency, the radiator is more or less a full-size 1/2 wave radiator. .................................................... No argument about the above statement. The argument is a 130ft wire with open feeders will radiate better than a 32 ft coax fed dipole (or trapped dipole) on 20 mtrs. A 130ft antenna at 20 mtrs is 2 wavelengths long. Fed with open wire feeders this antenna will outperform a 32ft 20mtr wire dipole. This antenna will have gain in some directions over a dipole and the pattern will be much different than a dipole. The Idea is Actually pretty simple. Say you want to work HF mobile. What is going to radiate more RF and be more efficient? A 4ft whip or a 8.5 ft whip. Same idea with the 130 ft wire. It has more radiating area than a 32ft dipole and will be a better antenna. If bigger was not better we would all be using a rubber duck to transmit on hf. K9IUQ
W4LGH2007-03-09
RE: Benchmarks
Mike W4EF...I agress with what you are saying. I agree that balanced line has a lot less loss than un-balanced. But I still contend that it is very hard to keep balanced line balanced from the shack to the antenna, due to outside influences. Once out of balance, it will radiate. This is one of the reasons they invented coax was to stop these outside influences. most communications engineers will agree the loss of the coax is easier to deal with than trying to keep a balanced line balanced. Bird droppings, the salt, especially here in Florida, and many other factors will change this, even simple rain, much less ice and snow will change it.

As for the tuner at the antenna, I am certainly not talking about you typical shack tuner. I am talking about loading coils for this tuning. This will in effect make the antenna electrically resonant.
An example here would be a screwdriver antenna with a 48" whip. The screwdriver has an adjustable loading coil to tune the antenna into resonance. Now take the same 48" whip and hook it to your shack tuner, it will make it see a 50ohm load, but you can't possible expect it to work as well as the screwdriver.

I guess, maybe, the confusion has been in the defination of tunnig your antenna. If you want to define that as matching the impedance of your antenna system at the back of your radio for max energy transfer...so be it, but if you think you are tuning your antenna into resonance to get max energy transfer, you are only fooling yourself.

I have made many tests myself, using 1/2 wave resonant antennas, and many non-resonant multi-band antennas, and the results have always been the same.
The antennas were configured the same heights and directions, and the tests were done in a full 360 degree circle. The results always showed 1 to 2 S-units higher on receive, which can be any where between 4db to 12db more signal, which WILL make a difference on receiving someone or NOT. On the transmit side the signal was any where between 3db to 6db stronger. Again a fair amount of difference.

Again these were tests that I actually did, and the results were actual, not something read out of a book. AND I am not saying don't read books, but don't accept everything you read as 100% hardcore FACT. The laws of physics haven't and won't change, but there have been many improvements with test equipment, and actual test proceedures that have changed many of the earlier finding.

Everyone would have argued with you 30 years ago if you told them you could talk around the world on 1.8Ghz w/.6watt of power, but we are doing it today. Yes it takes lots of repeaters, but effectively from your 6/10th watt cell phone you can talk anywhere in the world, and ANY time. 30 yer ago everyone would tell you that 1.8ghz was strictly point to point and needed large parabolic antennas. Was that not a FACT then, yes, is it a fact now, NO! Did the laws of physics change...NO! Technology changed! No one has written anything NEW about ham radio in over 30 years.
But the rest of the communications industry has many publications out, new testing proceedures, new equipment to actually show results..

But seriously, I have grown very tired of trying to lead this horse to water, he just won't drink.

73 de W4LGH - Alan

Reply to a comment by : W4EF on 2007-03-08

W4LGH wrote: >>With all the info that has bene passed back and forth, I still maintain that an antenna tuner hooked to coax (unbalanced line) is absurd, as you are doing NOTHING to the antenna itself, you may be tuning the entire antenna system, but NOT the part that is doing the most good. Move the tuner out to the antenna, now you are actually loading the antenna into resonance.<< There is no difference between the two cases above, Alan. In each case, all you are doing is impedance matching. Neither method modifies shape of the current distribution on the antenna. The latter (matching at the antenna) is only desireable to the extent that it minimizes feedline loss. True antenna "loading" actually modifies the shape of the current distribution along the radiator. This is why lumped element center inductive loading or distributed capacitive end-loading (i.e. capacity hat) are superior to base loading which is really nothing more than glorified impedance matching. When I load my 45' 160 meter vertical with a combination of center inductive loading and top-hat wires, I am actually improving the current distribution (making it more uniform). This raises the radiation resistance of the antenna relative to the ground losses thereby making the antenna more efficient that it would be if I just impedance matched the unloaded 45' radiator at the base. >>At this point I am not sure that using balanced line to an inside tuner is really good. It may work for you, because of low loss, and I still think the balanced wire or at least its resistance is becoming part of the antenna, and you are in effect tuning it into the overall picture.<< If the balanced feedline is close to the ground or nearby metal objects, you don't want it to be "tuned into the overall picture" at least in the sense that you don't want it radiating. You want it to carry energy to the antenna. If the open-wire feeder couples into the ground or nearby metal object it could actually end up being more lossy than coaxial line. There are instances where you want the feedline to radiate, as in the case of using a dipole fed against ground as a "T" or Marconi, but in that case you intentionally force all the feedline current to be "common mode". >> A good test would be to disconnect it from the antenna outside, short the end, its still balanced, and load it up on your tuner. I think you will be surprised at what you will hear, see and who you can talk to! You can also try the same with your coax, be it RG8X or 7/8" hard line, short the end at the antenna, load it up. If you have one of these super tuners it will probably load, but you won't hear much, much less do any talking. Easy tests, and will PROVE beyond a doubt! Try it sometime. << As I said before the fact that the balanced line may radiate more doesn't mean that it's a good thing. Feedline radiation is usually undesireable. If I go to the trouble of getting an antenna 100 feet high, I don't want the portion of the feedline that is 10 feet off the ground radiating. I may not even want the portion of the feedline that is 100 feet off the ground radiating if it screws up the radiation pattern. 73, Mike W4EF (from Eastern Ohio where nothing useful was ever invented)................
Reply to a comment by : W4LGH on 2007-03-08

YEP! I said I wouldn't but now I know..Its the "New Jersey Attitude". Man if Jersey is so damn GREAT, why the hell do they keep moving down here to Florida? Then try to make it like Jersey? Just stay up there and KEEP it all to yourselves! Ok..now its all yours. Tear it up boy!
Reply to a comment by : KD2BD on 2007-03-08

W4GLH (??) wrote: > or maybe its just your New Jersey attitude.. It's the same "New Jersey Attitude" that brought you the light bulb, the phonograph, the motion picture, the discovery of the Edison Effect (which lead to the invention of the vacuum tube), the transistor, the world's first electric power distribution system, the C and C++ programming languages, the Unix operating system, the radio work of Sarnoff and Marconi, the physics work of Einstein, the world's first FM radio broadcasts by Major Armstrong, and the world's first EME contact from my current home town. > But.... > You said..."A quarter-wave vertical is NOT an > isotropic source. A quarter-wave vertical has the > same directivity, gain, and capture area of a > half-wave dipole. Mankind has yet to build an > isotropic antenna. It is simply a theoretical > reference." > > If you think a 1/4vertical and a 1/2wave vertical > are the same, you need to go back and do some > studing! Maybe reading classes... I stand by what I said (and you quoted): A quarter-wave VERTICAL has the same directivity, gain, and capture area of a half-wave DIPOLE. > You got to keep apples with apples dude. Thanks for the advice. I'll try to do that next time. > Its truely amasing how people read what they want > into something and not what it says. I agree. It *IS* amazing... And thank you for demonstrating yet another perfect example.
Reply to a comment by : KD2BD on 2007-03-08

> So my questione here is..if you already have one in > your radio/amp whatever, why ADD a 2nd one to the mix? Because multi-band antennas provide absolutely no discrimination against harmonic radiation. A tuner in-line with a multi-band antenna helps ensure the antenna in use is resonant ONLY on the band of interest, not on all the other bands as well. As such, its use is simply a wise application of good engineering practice (FCC Part 97.101). 73, de John, KD2BD
Reply to a comment by : KD2BD on 2007-03-08

> Let's use a 1/4wave vertical as an example. Theory > tells us that when energy is applied it should > produce a perfect 360degree ball. We know this > isn't totally true because of outside influences, > but theory say this, its the isotropic antenna > effect. "Theory" doesn't say this at all! A quarter-wave vertical is NOT an isotropic source. A quarter-wave vertical has the same directivity, gain, and capture area of a half-wave dipole. Mankind has yet to build an isotropic antenna. It is simply a theoretical reference. Even an infinitesimally small dipole exhibits directivity and a gain of 1.76 dBi, just 0.38 dB below that of a full-sized, half-wave dipole. 73, de John, KD2BD
Reply to a comment by : MLMAN_EE on 2007-03-08

>K9IUQ >If bigger was not better we would all be using a >rubber duck to transmit on hf. Another brilliant statement. Bigger is NOT always better! Anytime you build an antenna to produce "gain" you are robbing Peter to pay Paul, as the ONLY way an antenna can show any gain is to direct more energy into a given direction. Let's use a 1/4wave vertical as an example. Theory tells us that when energy is applied it should produce a perfect 360degree ball. We know this isn't totally true because of outside influences, but theory say this, its the isotropic antenna effect. now you go to a 1/2wave vertical, and you compress this ball down expanding the outer edges, thus your 2.1db of gain. now you go to a 5/8wave and you compress this ball down some more, now producing 3db of gain, but your radiation pattern has changed, probably not going to effect vhf signals, but with hf signals you have lowered your take off angle, thus making larger hops during skip probagation. this might give you a super signal in Europe, but you might find you can't work a guy 500miles away. Bigger is NOT better, and one should have several antennas to do different things. NO ONE ANTENNA WILL DO IT ALL!! Although the StepIR comes pretty damn close. but then we won't go into resonant antennas again, our experts on here don't like them, they rather use lossy devices. ab8sw bill
Reply to a comment by : W4EF on 2007-03-07

K9IUQ wrote: >>No argument about the above statement. The argument is a 130ft wire with open feeders will radiate better than a 32 ft coax fed dipole (or trapped dipole) on 20 mtrs.<< Ok, I see what you are driving at, Stan. I should have read your post more carefully. I stand by what I wrote, however, at least in terms of efficiency of radiation (power entering coax vs. power radiated by antenna into space). What you are talking about with the 130 foot open-wire antenna is directivity. Directivity is a "rob Peter to pay Paul" zero-sum-game phenomenon. The 130ft long antenna open wire fed antenna will have significantly more gain on 20 meters than the trap dipole, but mainly because it has significantly greater directivity, not because it has better efficiency. Gain is as Martha would say "a good thing" but only if it occurs in a desireable direction. Since directivity is "robbing Peter to pay Paul", you will be worse off in some directions with the 130ft open-wire fed antenna than with the trapped dipole. Maybe this is okay (say you want to keep a schedule and you point the lobe of the 130ft antenna at the person you have your schedule with), but for that reason it's important to make the distinction between efficiency improvements (net improvement in all directions) versus directivity improvements (net improvement in one direction(s) with an equal net penalty in some other direction(s)). 73, Mike W4EF.....................
Reply to a comment by : K9IUQ on 2007-03-07

W4EF says MILF_MAN is right in this case. A trapped dipole is most efficient on the highest band of operation since at that frequency, the radiator is more or less a full-size 1/2 wave radiator. .................................................... No argument about the above statement. The argument is a 130ft wire with open feeders will radiate better than a 32 ft coax fed dipole (or trapped dipole) on 20 mtrs. A 130ft antenna at 20 mtrs is 2 wavelengths long. Fed with open wire feeders this antenna will outperform a 32ft 20mtr wire dipole. This antenna will have gain in some directions over a dipole and the pattern will be much different than a dipole. The Idea is Actually pretty simple. Say you want to work HF mobile. What is going to radiate more RF and be more efficient? A 4ft whip or a 8.5 ft whip. Same idea with the 130 ft wire. It has more radiating area than a 32ft dipole and will be a better antenna. If bigger was not better we would all be using a rubber duck to transmit on hf. K9IUQ
W4EF2007-03-08
RE: Benchmarks
W4LGH wrote:

>>With all the info that has bene passed back and forth, I still maintain that an antenna tuner hooked to coax (unbalanced line) is absurd, as you are doing NOTHING to the antenna itself, you may be tuning the entire antenna system, but NOT the part that is doing the most good. Move the tuner out to the antenna, now you are actually loading the antenna into resonance.<<

There is no difference between the two cases above, Alan. In each case, all you are doing is impedance matching. Neither method modifies shape of the current distribution on the antenna. The latter (matching at the antenna) is only desireable to the extent that it minimizes feedline loss. True antenna "loading" actually modifies the shape of the current distribution along the radiator. This is why lumped element center inductive loading or distributed capacitive end-loading (i.e. capacity hat) are superior to base loading which is really nothing more than glorified impedance matching. When I load my 45' 160 meter vertical with a combination of center inductive loading and top-hat wires, I am actually improving the current distribution (making it more uniform). This raises the radiation resistance of the antenna relative to the ground losses thereby making the antenna more efficient that it would be if I just impedance matched the unloaded 45' radiator at the base.

>>At this point I am not sure that using balanced line to an inside tuner is really good. It may work for you, because of low loss, and I still think the balanced wire or at least its resistance is becoming part of the antenna, and you are in effect tuning it into the overall picture.<<

If the balanced feedline is close to the ground or nearby metal objects, you don't want it to be "tuned into the overall picture" at least in the sense that you don't want it radiating. You want it to carry energy to the antenna. If the open-wire feeder couples into the ground or nearby metal object it could actually end up being more lossy than coaxial line.
There are instances where you want the feedline to radiate, as in the case of using a dipole fed against ground as a "T" or Marconi, but in that case you intentionally force all the feedline current to be "common mode".

>> A good test would be to disconnect it from the antenna outside, short the end, its still balanced, and load it up on your tuner. I think you will be surprised at what you will hear, see and who you can talk to! You can also try the same with your coax, be it RG8X or 7/8" hard line, short the end at the antenna, load it up. If you have one of these super tuners it will probably load, but you won't hear much, much less do any talking. Easy tests, and will PROVE beyond a doubt! Try it sometime. <<

As I said before the fact that the balanced line may radiate more doesn't mean that it's a good thing. Feedline radiation is usually undesireable. If I go to the trouble of getting an antenna 100 feet high, I don't want the portion of the feedline that is 10 feet off the ground radiating. I may not even want the portion of the feedline that is 100 feet off the ground radiating if it screws up the radiation pattern.

73, Mike W4EF (from Eastern Ohio where nothing useful was ever invented)................
Reply to a comment by : W4LGH on 2007-03-08

YEP! I said I wouldn't but now I know..Its the "New Jersey Attitude". Man if Jersey is so damn GREAT, why the hell do they keep moving down here to Florida? Then try to make it like Jersey? Just stay up there and KEEP it all to yourselves! Ok..now its all yours. Tear it up boy!
Reply to a comment by : KD2BD on 2007-03-08

W4GLH (??) wrote: > or maybe its just your New Jersey attitude.. It's the same "New Jersey Attitude" that brought you the light bulb, the phonograph, the motion picture, the discovery of the Edison Effect (which lead to the invention of the vacuum tube), the transistor, the world's first electric power distribution system, the C and C++ programming languages, the Unix operating system, the radio work of Sarnoff and Marconi, the physics work of Einstein, the world's first FM radio broadcasts by Major Armstrong, and the world's first EME contact from my current home town. > But.... > You said..."A quarter-wave vertical is NOT an > isotropic source. A quarter-wave vertical has the > same directivity, gain, and capture area of a > half-wave dipole. Mankind has yet to build an > isotropic antenna. It is simply a theoretical > reference." > > If you think a 1/4vertical and a 1/2wave vertical > are the same, you need to go back and do some > studing! Maybe reading classes... I stand by what I said (and you quoted): A quarter-wave VERTICAL has the same directivity, gain, and capture area of a half-wave DIPOLE. > You got to keep apples with apples dude. Thanks for the advice. I'll try to do that next time. > Its truely amasing how people read what they want > into something and not what it says. I agree. It *IS* amazing... And thank you for demonstrating yet another perfect example.
Reply to a comment by : KD2BD on 2007-03-08

> So my questione here is..if you already have one in > your radio/amp whatever, why ADD a 2nd one to the mix? Because multi-band antennas provide absolutely no discrimination against harmonic radiation. A tuner in-line with a multi-band antenna helps ensure the antenna in use is resonant ONLY on the band of interest, not on all the other bands as well. As such, its use is simply a wise application of good engineering practice (FCC Part 97.101). 73, de John, KD2BD
Reply to a comment by : KD2BD on 2007-03-08

> Let's use a 1/4wave vertical as an example. Theory > tells us that when energy is applied it should > produce a perfect 360degree ball. We know this > isn't totally true because of outside influences, > but theory say this, its the isotropic antenna > effect. "Theory" doesn't say this at all! A quarter-wave vertical is NOT an isotropic source. A quarter-wave vertical has the same directivity, gain, and capture area of a half-wave dipole. Mankind has yet to build an isotropic antenna. It is simply a theoretical reference. Even an infinitesimally small dipole exhibits directivity and a gain of 1.76 dBi, just 0.38 dB below that of a full-sized, half-wave dipole. 73, de John, KD2BD
Reply to a comment by : MLMAN_EE on 2007-03-08

>K9IUQ >If bigger was not better we would all be using a >rubber duck to transmit on hf. Another brilliant statement. Bigger is NOT always better! Anytime you build an antenna to produce "gain" you are robbing Peter to pay Paul, as the ONLY way an antenna can show any gain is to direct more energy into a given direction. Let's use a 1/4wave vertical as an example. Theory tells us that when energy is applied it should produce a perfect 360degree ball. We know this isn't totally true because of outside influences, but theory say this, its the isotropic antenna effect. now you go to a 1/2wave vertical, and you compress this ball down expanding the outer edges, thus your 2.1db of gain. now you go to a 5/8wave and you compress this ball down some more, now producing 3db of gain, but your radiation pattern has changed, probably not going to effect vhf signals, but with hf signals you have lowered your take off angle, thus making larger hops during skip probagation. this might give you a super signal in Europe, but you might find you can't work a guy 500miles away. Bigger is NOT better, and one should have several antennas to do different things. NO ONE ANTENNA WILL DO IT ALL!! Although the StepIR comes pretty damn close. but then we won't go into resonant antennas again, our experts on here don't like them, they rather use lossy devices. ab8sw bill
Reply to a comment by : W4EF on 2007-03-07

K9IUQ wrote: >>No argument about the above statement. The argument is a 130ft wire with open feeders will radiate better than a 32 ft coax fed dipole (or trapped dipole) on 20 mtrs.<< Ok, I see what you are driving at, Stan. I should have read your post more carefully. I stand by what I wrote, however, at least in terms of efficiency of radiation (power entering coax vs. power radiated by antenna into space). What you are talking about with the 130 foot open-wire antenna is directivity. Directivity is a "rob Peter to pay Paul" zero-sum-game phenomenon. The 130ft long antenna open wire fed antenna will have significantly more gain on 20 meters than the trap dipole, but mainly because it has significantly greater directivity, not because it has better efficiency. Gain is as Martha would say "a good thing" but only if it occurs in a desireable direction. Since directivity is "robbing Peter to pay Paul", you will be worse off in some directions with the 130ft open-wire fed antenna than with the trapped dipole. Maybe this is okay (say you want to keep a schedule and you point the lobe of the 130ft antenna at the person you have your schedule with), but for that reason it's important to make the distinction between efficiency improvements (net improvement in all directions) versus directivity improvements (net improvement in one direction(s) with an equal net penalty in some other direction(s)). 73, Mike W4EF.....................
Reply to a comment by : K9IUQ on 2007-03-07

W4EF says MILF_MAN is right in this case. A trapped dipole is most efficient on the highest band of operation since at that frequency, the radiator is more or less a full-size 1/2 wave radiator. .................................................... No argument about the above statement. The argument is a 130ft wire with open feeders will radiate better than a 32 ft coax fed dipole (or trapped dipole) on 20 mtrs. A 130ft antenna at 20 mtrs is 2 wavelengths long. Fed with open wire feeders this antenna will outperform a 32ft 20mtr wire dipole. This antenna will have gain in some directions over a dipole and the pattern will be much different than a dipole. The Idea is Actually pretty simple. Say you want to work HF mobile. What is going to radiate more RF and be more efficient? A 4ft whip or a 8.5 ft whip. Same idea with the 130 ft wire. It has more radiating area than a 32ft dipole and will be a better antenna. If bigger was not better we would all be using a rubber duck to transmit on hf. K9IUQ
W4LGH2007-03-08
RE: Benchmarks
YEP! I said I wouldn't but now I know..Its the "New Jersey Attitude". Man if Jersey is so damn GREAT, why the hell do they keep moving down here to Florida? Then try to make it like Jersey? Just stay up there and KEEP it all to yourselves!

Ok..now its all yours. Tear it up boy!
Reply to a comment by : KD2BD on 2007-03-08

W4GLH (??) wrote: > or maybe its just your New Jersey attitude.. It's the same "New Jersey Attitude" that brought you the light bulb, the phonograph, the motion picture, the discovery of the Edison Effect (which lead to the invention of the vacuum tube), the transistor, the world's first electric power distribution system, the C and C++ programming languages, the Unix operating system, the radio work of Sarnoff and Marconi, the physics work of Einstein, the world's first FM radio broadcasts by Major Armstrong, and the world's first EME contact from my current home town. > But.... > You said..."A quarter-wave vertical is NOT an > isotropic source. A quarter-wave vertical has the > same directivity, gain, and capture area of a > half-wave dipole. Mankind has yet to build an > isotropic antenna. It is simply a theoretical > reference." > > If you think a 1/4vertical and a 1/2wave vertical > are the same, you need to go back and do some > studing! Maybe reading classes... I stand by what I said (and you quoted): A quarter-wave VERTICAL has the same directivity, gain, and capture area of a half-wave DIPOLE. > You got to keep apples with apples dude. Thanks for the advice. I'll try to do that next time. > Its truely amasing how people read what they want > into something and not what it says. I agree. It *IS* amazing... And thank you for demonstrating yet another perfect example.
Reply to a comment by : KD2BD on 2007-03-08

> So my questione here is..if you already have one in > your radio/amp whatever, why ADD a 2nd one to the mix? Because multi-band antennas provide absolutely no discrimination against harmonic radiation. A tuner in-line with a multi-band antenna helps ensure the antenna in use is resonant ONLY on the band of interest, not on all the other bands as well. As such, its use is simply a wise application of good engineering practice (FCC Part 97.101). 73, de John, KD2BD
Reply to a comment by : KD2BD on 2007-03-08

> Let's use a 1/4wave vertical as an example. Theory > tells us that when energy is applied it should > produce a perfect 360degree ball. We know this > isn't totally true because of outside influences, > but theory say this, its the isotropic antenna > effect. "Theory" doesn't say this at all! A quarter-wave vertical is NOT an isotropic source. A quarter-wave vertical has the same directivity, gain, and capture area of a half-wave dipole. Mankind has yet to build an isotropic antenna. It is simply a theoretical reference. Even an infinitesimally small dipole exhibits directivity and a gain of 1.76 dBi, just 0.38 dB below that of a full-sized, half-wave dipole. 73, de John, KD2BD
Reply to a comment by : MLMAN_EE on 2007-03-08

>K9IUQ >If bigger was not better we would all be using a >rubber duck to transmit on hf. Another brilliant statement. Bigger is NOT always better! Anytime you build an antenna to produce "gain" you are robbing Peter to pay Paul, as the ONLY way an antenna can show any gain is to direct more energy into a given direction. Let's use a 1/4wave vertical as an example. Theory tells us that when energy is applied it should produce a perfect 360degree ball. We know this isn't totally true because of outside influences, but theory say this, its the isotropic antenna effect. now you go to a 1/2wave vertical, and you compress this ball down expanding the outer edges, thus your 2.1db of gain. now you go to a 5/8wave and you compress this ball down some more, now producing 3db of gain, but your radiation pattern has changed, probably not going to effect vhf signals, but with hf signals you have lowered your take off angle, thus making larger hops during skip probagation. this might give you a super signal in Europe, but you might find you can't work a guy 500miles away. Bigger is NOT better, and one should have several antennas to do different things. NO ONE ANTENNA WILL DO IT ALL!! Although the StepIR comes pretty damn close. but then we won't go into resonant antennas again, our experts on here don't like them, they rather use lossy devices. ab8sw bill
Reply to a comment by : W4EF on 2007-03-07

K9IUQ wrote: >>No argument about the above statement. The argument is a 130ft wire with open feeders will radiate better than a 32 ft coax fed dipole (or trapped dipole) on 20 mtrs.<< Ok, I see what you are driving at, Stan. I should have read your post more carefully. I stand by what I wrote, however, at least in terms of efficiency of radiation (power entering coax vs. power radiated by antenna into space). What you are talking about with the 130 foot open-wire antenna is directivity. Directivity is a "rob Peter to pay Paul" zero-sum-game phenomenon. The 130ft long antenna open wire fed antenna will have significantly more gain on 20 meters than the trap dipole, but mainly because it has significantly greater directivity, not because it has better efficiency. Gain is as Martha would say "a good thing" but only if it occurs in a desireable direction. Since directivity is "robbing Peter to pay Paul", you will be worse off in some directions with the 130ft open-wire fed antenna than with the trapped dipole. Maybe this is okay (say you want to keep a schedule and you point the lobe of the 130ft antenna at the person you have your schedule with), but for that reason it's important to make the distinction between efficiency improvements (net improvement in all directions) versus directivity improvements (net improvement in one direction(s) with an equal net penalty in some other direction(s)). 73, Mike W4EF.....................
Reply to a comment by : K9IUQ on 2007-03-07

W4EF says MILF_MAN is right in this case. A trapped dipole is most efficient on the highest band of operation since at that frequency, the radiator is more or less a full-size 1/2 wave radiator. .................................................... No argument about the above statement. The argument is a 130ft wire with open feeders will radiate better than a 32 ft coax fed dipole (or trapped dipole) on 20 mtrs. A 130ft antenna at 20 mtrs is 2 wavelengths long. Fed with open wire feeders this antenna will outperform a 32ft 20mtr wire dipole. This antenna will have gain in some directions over a dipole and the pattern will be much different than a dipole. The Idea is Actually pretty simple. Say you want to work HF mobile. What is going to radiate more RF and be more efficient? A 4ft whip or a 8.5 ft whip. Same idea with the 130 ft wire. It has more radiating area than a 32ft dipole and will be a better antenna. If bigger was not better we would all be using a rubber duck to transmit on hf. K9IUQ
KD2BD2007-03-08
RE: Benchmarks
W4GLH (??) wrote:

> or maybe its just your New Jersey attitude..

It's the same "New Jersey Attitude" that brought you the light bulb, the phonograph, the motion picture, the discovery of the Edison Effect (which lead to the invention of the vacuum tube), the transistor, the world's first electric power distribution system, the C and C++ programming languages, the Unix operating system, the radio work of Sarnoff and Marconi, the physics work of Einstein, the world's first FM radio broadcasts by Major Armstrong, and the world's first EME contact from my current home town.

> But....
> You said..."A quarter-wave vertical is NOT an
> isotropic source. A quarter-wave vertical has the
> same directivity, gain, and capture area of a
> half-wave dipole. Mankind has yet to build an
> isotropic antenna. It is simply a theoretical
> reference."
>
> If you think a 1/4vertical and a 1/2wave vertical
> are the same, you need to go back and do some
> studing! Maybe reading classes...

I stand by what I said (and you quoted):

A quarter-wave VERTICAL has the same directivity, gain, and capture area of a half-wave DIPOLE.

> You got to keep apples with apples dude.

Thanks for the advice. I'll try to do that next time.

> Its truely amasing how people read what they want
> into something and not what it says.

I agree. It *IS* amazing...

And thank you for demonstrating yet another perfect example.
Reply to a comment by : KD2BD on 2007-03-08

> So my questione here is..if you already have one in > your radio/amp whatever, why ADD a 2nd one to the mix? Because multi-band antennas provide absolutely no discrimination against harmonic radiation. A tuner in-line with a multi-band antenna helps ensure the antenna in use is resonant ONLY on the band of interest, not on all the other bands as well. As such, its use is simply a wise application of good engineering practice (FCC Part 97.101). 73, de John, KD2BD
Reply to a comment by : KD2BD on 2007-03-08

> Let's use a 1/4wave vertical as an example. Theory > tells us that when energy is applied it should > produce a perfect 360degree ball. We know this > isn't totally true because of outside influences, > but theory say this, its the isotropic antenna > effect. "Theory" doesn't say this at all! A quarter-wave vertical is NOT an isotropic source. A quarter-wave vertical has the same directivity, gain, and capture area of a half-wave dipole. Mankind has yet to build an isotropic antenna. It is simply a theoretical reference. Even an infinitesimally small dipole exhibits directivity and a gain of 1.76 dBi, just 0.38 dB below that of a full-sized, half-wave dipole. 73, de John, KD2BD
Reply to a comment by : MLMAN_EE on 2007-03-08

>K9IUQ >If bigger was not better we would all be using a >rubber duck to transmit on hf. Another brilliant statement. Bigger is NOT always better! Anytime you build an antenna to produce "gain" you are robbing Peter to pay Paul, as the ONLY way an antenna can show any gain is to direct more energy into a given direction. Let's use a 1/4wave vertical as an example. Theory tells us that when energy is applied it should produce a perfect 360degree ball. We know this isn't totally true because of outside influences, but theory say this, its the isotropic antenna effect. now you go to a 1/2wave vertical, and you compress this ball down expanding the outer edges, thus your 2.1db of gain. now you go to a 5/8wave and you compress this ball down some more, now producing 3db of gain, but your radiation pattern has changed, probably not going to effect vhf signals, but with hf signals you have lowered your take off angle, thus making larger hops during skip probagation. this might give you a super signal in Europe, but you might find you can't work a guy 500miles away. Bigger is NOT better, and one should have several antennas to do different things. NO ONE ANTENNA WILL DO IT ALL!! Although the StepIR comes pretty damn close. but then we won't go into resonant antennas again, our experts on here don't like them, they rather use lossy devices. ab8sw bill
Reply to a comment by : W4EF on 2007-03-07

K9IUQ wrote: >>No argument about the above statement. The argument is a 130ft wire with open feeders will radiate better than a 32 ft coax fed dipole (or trapped dipole) on 20 mtrs.<< Ok, I see what you are driving at, Stan. I should have read your post more carefully. I stand by what I wrote, however, at least in terms of efficiency of radiation (power entering coax vs. power radiated by antenna into space). What you are talking about with the 130 foot open-wire antenna is directivity. Directivity is a "rob Peter to pay Paul" zero-sum-game phenomenon. The 130ft long antenna open wire fed antenna will have significantly more gain on 20 meters than the trap dipole, but mainly because it has significantly greater directivity, not because it has better efficiency. Gain is as Martha would say "a good thing" but only if it occurs in a desireable direction. Since directivity is "robbing Peter to pay Paul", you will be worse off in some directions with the 130ft open-wire fed antenna than with the trapped dipole. Maybe this is okay (say you want to keep a schedule and you point the lobe of the 130ft antenna at the person you have your schedule with), but for that reason it's important to make the distinction between efficiency improvements (net improvement in all directions) versus directivity improvements (net improvement in one direction(s) with an equal net penalty in some other direction(s)). 73, Mike W4EF.....................
Reply to a comment by : K9IUQ on 2007-03-07

W4EF says MILF_MAN is right in this case. A trapped dipole is most efficient on the highest band of operation since at that frequency, the radiator is more or less a full-size 1/2 wave radiator. .................................................... No argument about the above statement. The argument is a 130ft wire with open feeders will radiate better than a 32 ft coax fed dipole (or trapped dipole) on 20 mtrs. A 130ft antenna at 20 mtrs is 2 wavelengths long. Fed with open wire feeders this antenna will outperform a 32ft 20mtr wire dipole. This antenna will have gain in some directions over a dipole and the pattern will be much different than a dipole. The Idea is Actually pretty simple. Say you want to work HF mobile. What is going to radiate more RF and be more efficient? A 4ft whip or a 8.5 ft whip. Same idea with the 130 ft wire. It has more radiating area than a 32ft dipole and will be a better antenna. If bigger was not better we would all be using a rubber duck to transmit on hf. K9IUQ
W4LGH2007-03-08
RE: Benchmarks
I think that Mr John, KD2BD needs to have the last word at anything posted here. I guess john you have something to prove, or maybe its just your New Jersey attitude...maybe both, I just can't tell.

But....
You said..."A quarter-wave vertical is NOT an isotropic source. A quarter-wave vertical has the same directivity, gain, and capture area of a half-wave dipole. Mankind has yet to build an isotropic antenna. It is simply a theoretical reference."

If you think a 1/4vertical and a 1/2wave vertical are the same, you need to go back and do some studing! Maybe reading classes... the example given in MLMAN's statement was 1/4wave vertical and a 1/2wave vertical. We all know that a 1/4wave vertical is one side of a 1/2wave dipole. You got to keep apples with apples dude. I also went back and read it several times and it did NOT say a 1/4wave was an isotropic antenna, again we all know this simply does NOT exsist. What it said was its that isotropic type of effect, I think meaning in a perfect world it would radiate a perfect 360 deg ball around the antenna.

Its truely amasing how people read what they want into something and not what it says. Guess this is why our govt is so screwed up. In any event, I am done, so you can come back and get the last word. I said what I wanted to say in my last post...and I stand behind it 100%!!


The floor is all your John...

de W4LGH Alan
http://www.w4lgh.com

Reply to a comment by : KD2BD on 2007-03-08

> So my questione here is..if you already have one in > your radio/amp whatever, why ADD a 2nd one to the mix? Because multi-band antennas provide absolutely no discrimination against harmonic radiation. A tuner in-line with a multi-band antenna helps ensure the antenna in use is resonant ONLY on the band of interest, not on all the other bands as well. As such, its use is simply a wise application of good engineering practice (FCC Part 97.101). 73, de John, KD2BD
Reply to a comment by : KD2BD on 2007-03-08

> Let's use a 1/4wave vertical as an example. Theory > tells us that when energy is applied it should > produce a perfect 360degree ball. We know this > isn't totally true because of outside influences, > but theory say this, its the isotropic antenna > effect. "Theory" doesn't say this at all! A quarter-wave vertical is NOT an isotropic source. A quarter-wave vertical has the same directivity, gain, and capture area of a half-wave dipole. Mankind has yet to build an isotropic antenna. It is simply a theoretical reference. Even an infinitesimally small dipole exhibits directivity and a gain of 1.76 dBi, just 0.38 dB below that of a full-sized, half-wave dipole. 73, de John, KD2BD
Reply to a comment by : MLMAN_EE on 2007-03-08

>K9IUQ >If bigger was not better we would all be using a >rubber duck to transmit on hf. Another brilliant statement. Bigger is NOT always better! Anytime you build an antenna to produce "gain" you are robbing Peter to pay Paul, as the ONLY way an antenna can show any gain is to direct more energy into a given direction. Let's use a 1/4wave vertical as an example. Theory tells us that when energy is applied it should produce a perfect 360degree ball. We know this isn't totally true because of outside influences, but theory say this, its the isotropic antenna effect. now you go to a 1/2wave vertical, and you compress this ball down expanding the outer edges, thus your 2.1db of gain. now you go to a 5/8wave and you compress this ball down some more, now producing 3db of gain, but your radiation pattern has changed, probably not going to effect vhf signals, but with hf signals you have lowered your take off angle, thus making larger hops during skip probagation. this might give you a super signal in Europe, but you might find you can't work a guy 500miles away. Bigger is NOT better, and one should have several antennas to do different things. NO ONE ANTENNA WILL DO IT ALL!! Although the StepIR comes pretty damn close. but then we won't go into resonant antennas again, our experts on here don't like them, they rather use lossy devices. ab8sw bill
Reply to a comment by : W4EF on 2007-03-07

K9IUQ wrote: >>No argument about the above statement. The argument is a 130ft wire with open feeders will radiate better than a 32 ft coax fed dipole (or trapped dipole) on 20 mtrs.<< Ok, I see what you are driving at, Stan. I should have read your post more carefully. I stand by what I wrote, however, at least in terms of efficiency of radiation (power entering coax vs. power radiated by antenna into space). What you are talking about with the 130 foot open-wire antenna is directivity. Directivity is a "rob Peter to pay Paul" zero-sum-game phenomenon. The 130ft long antenna open wire fed antenna will have significantly more gain on 20 meters than the trap dipole, but mainly because it has significantly greater directivity, not because it has better efficiency. Gain is as Martha would say "a good thing" but only if it occurs in a desireable direction. Since directivity is "robbing Peter to pay Paul", you will be worse off in some directions with the 130ft open-wire fed antenna than with the trapped dipole. Maybe this is okay (say you want to keep a schedule and you point the lobe of the 130ft antenna at the person you have your schedule with), but for that reason it's important to make the distinction between efficiency improvements (net improvement in all directions) versus directivity improvements (net improvement in one direction(s) with an equal net penalty in some other direction(s)). 73, Mike W4EF.....................
Reply to a comment by : K9IUQ on 2007-03-07

W4EF says MILF_MAN is right in this case. A trapped dipole is most efficient on the highest band of operation since at that frequency, the radiator is more or less a full-size 1/2 wave radiator. .................................................... No argument about the above statement. The argument is a 130ft wire with open feeders will radiate better than a 32 ft coax fed dipole (or trapped dipole) on 20 mtrs. A 130ft antenna at 20 mtrs is 2 wavelengths long. Fed with open wire feeders this antenna will outperform a 32ft 20mtr wire dipole. This antenna will have gain in some directions over a dipole and the pattern will be much different than a dipole. The Idea is Actually pretty simple. Say you want to work HF mobile. What is going to radiate more RF and be more efficient? A 4ft whip or a 8.5 ft whip. Same idea with the 130 ft wire. It has more radiating area than a 32ft dipole and will be a better antenna. If bigger was not better we would all be using a rubber duck to transmit on hf. K9IUQ
KD2BD2007-03-08
RE: Benchmarks
> So my questione here is..if you already have one in
> your radio/amp whatever, why ADD a 2nd one to the mix?

Because multi-band antennas provide absolutely no discrimination against harmonic radiation.

A tuner in-line with a multi-band antenna helps ensure the antenna in use is resonant ONLY on the band of interest, not on all the other bands as well.

As such, its use is simply a wise application of good engineering practice (FCC Part 97.101).


73, de John, KD2BD
Reply to a comment by : KD2BD on 2007-03-08

> Let's use a 1/4wave vertical as an example. Theory > tells us that when energy is applied it should > produce a perfect 360degree ball. We know this > isn't totally true because of outside influences, > but theory say this, its the isotropic antenna > effect. "Theory" doesn't say this at all! A quarter-wave vertical is NOT an isotropic source. A quarter-wave vertical has the same directivity, gain, and capture area of a half-wave dipole. Mankind has yet to build an isotropic antenna. It is simply a theoretical reference. Even an infinitesimally small dipole exhibits directivity and a gain of 1.76 dBi, just 0.38 dB below that of a full-sized, half-wave dipole. 73, de John, KD2BD
Reply to a comment by : MLMAN_EE on 2007-03-08

>K9IUQ >If bigger was not better we would all be using a >rubber duck to transmit on hf. Another brilliant statement. Bigger is NOT always better! Anytime you build an antenna to produce "gain" you are robbing Peter to pay Paul, as the ONLY way an antenna can show any gain is to direct more energy into a given direction. Let's use a 1/4wave vertical as an example. Theory tells us that when energy is applied it should produce a perfect 360degree ball. We know this isn't totally true because of outside influences, but theory say this, its the isotropic antenna effect. now you go to a 1/2wave vertical, and you compress this ball down expanding the outer edges, thus your 2.1db of gain. now you go to a 5/8wave and you compress this ball down some more, now producing 3db of gain, but your radiation pattern has changed, probably not going to effect vhf signals, but with hf signals you have lowered your take off angle, thus making larger hops during skip probagation. this might give you a super signal in Europe, but you might find you can't work a guy 500miles away. Bigger is NOT better, and one should have several antennas to do different things. NO ONE ANTENNA WILL DO IT ALL!! Although the StepIR comes pretty damn close. but then we won't go into resonant antennas again, our experts on here don't like them, they rather use lossy devices. ab8sw bill
Reply to a comment by : W4EF on 2007-03-07

K9IUQ wrote: >>No argument about the above statement. The argument is a 130ft wire with open feeders will radiate better than a 32 ft coax fed dipole (or trapped dipole) on 20 mtrs.<< Ok, I see what you are driving at, Stan. I should have read your post more carefully. I stand by what I wrote, however, at least in terms of efficiency of radiation (power entering coax vs. power radiated by antenna into space). What you are talking about with the 130 foot open-wire antenna is directivity. Directivity is a "rob Peter to pay Paul" zero-sum-game phenomenon. The 130ft long antenna open wire fed antenna will have significantly more gain on 20 meters than the trap dipole, but mainly because it has significantly greater directivity, not because it has better efficiency. Gain is as Martha would say "a good thing" but only if it occurs in a desireable direction. Since directivity is "robbing Peter to pay Paul", you will be worse off in some directions with the 130ft open-wire fed antenna than with the trapped dipole. Maybe this is okay (say you want to keep a schedule and you point the lobe of the 130ft antenna at the person you have your schedule with), but for that reason it's important to make the distinction between efficiency improvements (net improvement in all directions) versus directivity improvements (net improvement in one direction(s) with an equal net penalty in some other direction(s)). 73, Mike W4EF.....................
Reply to a comment by : K9IUQ on 2007-03-07

W4EF says MILF_MAN is right in this case. A trapped dipole is most efficient on the highest band of operation since at that frequency, the radiator is more or less a full-size 1/2 wave radiator. .................................................... No argument about the above statement. The argument is a 130ft wire with open feeders will radiate better than a 32 ft coax fed dipole (or trapped dipole) on 20 mtrs. A 130ft antenna at 20 mtrs is 2 wavelengths long. Fed with open wire feeders this antenna will outperform a 32ft 20mtr wire dipole. This antenna will have gain in some directions over a dipole and the pattern will be much different than a dipole. The Idea is Actually pretty simple. Say you want to work HF mobile. What is going to radiate more RF and be more efficient? A 4ft whip or a 8.5 ft whip. Same idea with the 130 ft wire. It has more radiating area than a 32ft dipole and will be a better antenna. If bigger was not better we would all be using a rubber duck to transmit on hf. K9IUQ
KD2BD2007-03-08
RE: Benchmarks
> Let's use a 1/4wave vertical as an example. Theory
> tells us that when energy is applied it should
> produce a perfect 360degree ball. We know this
> isn't totally true because of outside influences,
> but theory say this, its the isotropic antenna
> effect.

"Theory" doesn't say this at all!

A quarter-wave vertical is NOT an isotropic source. A quarter-wave vertical has the same directivity, gain, and capture area of a half-wave dipole.

Mankind has yet to build an isotropic antenna. It is simply a theoretical reference.

Even an infinitesimally small dipole exhibits directivity and a gain of 1.76 dBi, just 0.38 dB below that of a full-sized, half-wave dipole.


73, de John, KD2BD
Reply to a comment by : MLMAN_EE on 2007-03-08

>K9IUQ >If bigger was not better we would all be using a >rubber duck to transmit on hf. Another brilliant statement. Bigger is NOT always better! Anytime you build an antenna to produce "gain" you are robbing Peter to pay Paul, as the ONLY way an antenna can show any gain is to direct more energy into a given direction. Let's use a 1/4wave vertical as an example. Theory tells us that when energy is applied it should produce a perfect 360degree ball. We know this isn't totally true because of outside influences, but theory say this, its the isotropic antenna effect. now you go to a 1/2wave vertical, and you compress this ball down expanding the outer edges, thus your 2.1db of gain. now you go to a 5/8wave and you compress this ball down some more, now producing 3db of gain, but your radiation pattern has changed, probably not going to effect vhf signals, but with hf signals you have lowered your take off angle, thus making larger hops during skip probagation. this might give you a super signal in Europe, but you might find you can't work a guy 500miles away. Bigger is NOT better, and one should have several antennas to do different things. NO ONE ANTENNA WILL DO IT ALL!! Although the StepIR comes pretty damn close. but then we won't go into resonant antennas again, our experts on here don't like them, they rather use lossy devices. ab8sw bill
Reply to a comment by : W4EF on 2007-03-07

K9IUQ wrote: >>No argument about the above statement. The argument is a 130ft wire with open feeders will radiate better than a 32 ft coax fed dipole (or trapped dipole) on 20 mtrs.<< Ok, I see what you are driving at, Stan. I should have read your post more carefully. I stand by what I wrote, however, at least in terms of efficiency of radiation (power entering coax vs. power radiated by antenna into space). What you are talking about with the 130 foot open-wire antenna is directivity. Directivity is a "rob Peter to pay Paul" zero-sum-game phenomenon. The 130ft long antenna open wire fed antenna will have significantly more gain on 20 meters than the trap dipole, but mainly because it has significantly greater directivity, not because it has better efficiency. Gain is as Martha would say "a good thing" but only if it occurs in a desireable direction. Since directivity is "robbing Peter to pay Paul", you will be worse off in some directions with the 130ft open-wire fed antenna than with the trapped dipole. Maybe this is okay (say you want to keep a schedule and you point the lobe of the 130ft antenna at the person you have your schedule with), but for that reason it's important to make the distinction between efficiency improvements (net improvement in all directions) versus directivity improvements (net improvement in one direction(s) with an equal net penalty in some other direction(s)). 73, Mike W4EF.....................
Reply to a comment by : K9IUQ on 2007-03-07

W4EF says MILF_MAN is right in this case. A trapped dipole is most efficient on the highest band of operation since at that frequency, the radiator is more or less a full-size 1/2 wave radiator. .................................................... No argument about the above statement. The argument is a 130ft wire with open feeders will radiate better than a 32 ft coax fed dipole (or trapped dipole) on 20 mtrs. A 130ft antenna at 20 mtrs is 2 wavelengths long. Fed with open wire feeders this antenna will outperform a 32ft 20mtr wire dipole. This antenna will have gain in some directions over a dipole and the pattern will be much different than a dipole. The Idea is Actually pretty simple. Say you want to work HF mobile. What is going to radiate more RF and be more efficient? A 4ft whip or a 8.5 ft whip. Same idea with the 130 ft wire. It has more radiating area than a 32ft dipole and will be a better antenna. If bigger was not better we would all be using a rubber duck to transmit on hf. K9IUQ
W4LGH2007-03-08
RE: Benchmarks
Well this thread is now at the bottom of the pile. To say the very least, "Its been Interesting". It is truely amasing the different opinions that people have about how antennas work, the myths, the truths and even the 1/2 truths. If one was to go back and fully ready the original article, they would be amased. Here's an excerpt....

"By Alan, KØBG www.k0bg.com ~ The proliferation of antenna tuners and couplers speaks volumes. Seemingly, it's no longer necessary (or desirable as the case may be) to erect resonant antennas. With the tweak of a knob or two, it's possible to load up just about any chunk of metal and turn it into an antenna. Improbable as it may sound, some antenna tuners can be tuned up without an antenna connected! There are two hidden factors at play which most users miss.

The most common tuner configuration is the T network. It consists of two series capacitors (one each on the input and output), and a shunt inductor between them. The advantage over other designs like a Pi network is, the values of the capacitors can be much smaller in value (usually around 500 pF). Improperly tune them, add in a very high SWR impressed on the feed line, and it is not inconceivable for 90% on the input power being used to heat up the various parts. If you use one of these tuners, remember this simple rule; adjust the capacitors for the largest amount of capacitance consistent with a good match. If one or both of the caps are almost un-meshed, you haven't done it correctly, or the tuner is at the extreme edge of its matching capabilities. Either condition results in excessive losses.

What's more, the ability to match an antenna with a tuner means very little except that the tuner works. Some very popular antennas (a G5RV for example) can easily be made into an all band antenna with a tuner. What's missed is how well the antenna system is performing (remember, the tuner is part of the system). In too many cases the overall losses are more than the radiated power, and the radiation lobes are straight up! While you might be able to work everything you can hear, you're missing much more than you realize.

About this time you might be thinking antennas, sports cars, and diesel pickup trucks don't have much in common. Well they do, because their suitability for any given purpose is based on need."

With all the info that has bene passed back and forth, I still maintain that an antenna tuner hooked to coax (unbalanced line) is absurd, as you are doing NOTHING to the antenna itself, you may be tuning the entire antenna system, but NOT the part that is doing the most good. Move the tuner out to the antenna, now you are actually loading the antenna into resonance. At this point I am not sure that using balanced line to an inside tuner is really good. It may work for you, because of low loss, and I still think the balanced wire or at least its resistance is becoming part of the antenna, and you are in effect tuning it into the overall picture. A good test would be to disconnect it from the antenna outside, short the end, its still balanced, and load it up on your tuner. I think you will be surprised at what you will hear, see and who you can talk to! You can also try the same with your coax, be it RG8X or 7/8" hard line, short the end at the antenna, load it up. If you have one of these super tuners it will probably load, but you won't hear much, much less do any talking. Easy tests, and will PROVE beyond a doubt! Try it sometime.

You may come back with the PI network in teh amp, or tube radios, the inductors in the solid state radios as being a tuner, if you prefer to call it that then so be it. The tube network is tunable, over a small area, the solid state is NOT tunable, it is set to 50ohms. So my questione here is..if you already have one in your radio/amp whatever, why ADD a 2nd one to the mix? Also your auto-tuners built into solid state rigs...now you want to talk about loss?? The inductors and caps are very small, and again, this tuner has a very limited range usually no more than about 150ohms of match.

What those who believe in their tuners have done is try to CONVINCE themselves, what they did, which was take the EASY WAY out, is good enough for them. No ,not everyone has the room or finances to build and own an antenna farm, and maybe the easy way IS good enough for most amateurs, it certainly seems to be the case. However now with all this being said, again I maintain that in my "OPINION" using an antenna tuner inside you shack to MAKE something work that would NOT work on its OWN, is "ABSURD" and you are only fooling yourself.

LIke the original article said, you can haul a bar stoll in the back of a big truck, or you can strap a Grand Piano to the roof of your sports car, but what are you really doing here? and both are ABSURD!!

73, Hope you CAN in fact work everyone you Hear!
de W4LGH - Alan
http://www.w4lgh.com





Reply to a comment by : MLMAN_EE on 2007-03-08

>K9IUQ >If bigger was not better we would all be using a >rubber duck to transmit on hf. Another brilliant statement. Bigger is NOT always better! Anytime you build an antenna to produce "gain" you are robbing Peter to pay Paul, as the ONLY way an antenna can show any gain is to direct more energy into a given direction. Let's use a 1/4wave vertical as an example. Theory tells us that when energy is applied it should produce a perfect 360degree ball. We know this isn't totally true because of outside influences, but theory say this, its the isotropic antenna effect. now you go to a 1/2wave vertical, and you compress this ball down expanding the outer edges, thus your 2.1db of gain. now you go to a 5/8wave and you compress this ball down some more, now producing 3db of gain, but your radiation pattern has changed, probably not going to effect vhf signals, but with hf signals you have lowered your take off angle, thus making larger hops during skip probagation. this might give you a super signal in Europe, but you might find you can't work a guy 500miles away. Bigger is NOT better, and one should have several antennas to do different things. NO ONE ANTENNA WILL DO IT ALL!! Although the StepIR comes pretty damn close. but then we won't go into resonant antennas again, our experts on here don't like them, they rather use lossy devices. ab8sw bill
Reply to a comment by : W4EF on 2007-03-07

K9IUQ wrote: >>No argument about the above statement. The argument is a 130ft wire with open feeders will radiate better than a 32 ft coax fed dipole (or trapped dipole) on 20 mtrs.<< Ok, I see what you are driving at, Stan. I should have read your post more carefully. I stand by what I wrote, however, at least in terms of efficiency of radiation (power entering coax vs. power radiated by antenna into space). What you are talking about with the 130 foot open-wire antenna is directivity. Directivity is a "rob Peter to pay Paul" zero-sum-game phenomenon. The 130ft long antenna open wire fed antenna will have significantly more gain on 20 meters than the trap dipole, but mainly because it has significantly greater directivity, not because it has better efficiency. Gain is as Martha would say "a good thing" but only if it occurs in a desireable direction. Since directivity is "robbing Peter to pay Paul", you will be worse off in some directions with the 130ft open-wire fed antenna than with the trapped dipole. Maybe this is okay (say you want to keep a schedule and you point the lobe of the 130ft antenna at the person you have your schedule with), but for that reason it's important to make the distinction between efficiency improvements (net improvement in all directions) versus directivity improvements (net improvement in one direction(s) with an equal net penalty in some other direction(s)). 73, Mike W4EF.....................
Reply to a comment by : K9IUQ on 2007-03-07

W4EF says MILF_MAN is right in this case. A trapped dipole is most efficient on the highest band of operation since at that frequency, the radiator is more or less a full-size 1/2 wave radiator. .................................................... No argument about the above statement. The argument is a 130ft wire with open feeders will radiate better than a 32 ft coax fed dipole (or trapped dipole) on 20 mtrs. A 130ft antenna at 20 mtrs is 2 wavelengths long. Fed with open wire feeders this antenna will outperform a 32ft 20mtr wire dipole. This antenna will have gain in some directions over a dipole and the pattern will be much different than a dipole. The Idea is Actually pretty simple. Say you want to work HF mobile. What is going to radiate more RF and be more efficient? A 4ft whip or a 8.5 ft whip. Same idea with the 130 ft wire. It has more radiating area than a 32ft dipole and will be a better antenna. If bigger was not better we would all be using a rubber duck to transmit on hf. K9IUQ
MLMAN_EE2007-03-08
RE: Benchmarks
>K9IUQ
>If bigger was not better we would all be using a >rubber duck to transmit on hf.

Another brilliant statement. Bigger is NOT always better! Anytime you build an antenna to produce "gain" you are robbing Peter to pay Paul, as the ONLY way an antenna can show any gain is to direct more energy into a given direction. Let's use a 1/4wave vertical as an example. Theory tells us that when energy is applied it should produce a perfect 360degree ball. We know this isn't totally true because of outside influences, but theory say this, its the isotropic antenna effect. now you go to a 1/2wave vertical, and you compress this ball down expanding the outer edges, thus your 2.1db of gain. now you go to a 5/8wave and you compress this ball down some more, now producing 3db of gain, but your radiation pattern has changed, probably not going to effect vhf signals, but with hf signals you have lowered your take off angle, thus making larger hops during skip probagation. this might give you a super signal in Europe, but you might find you can't work a guy 500miles away.

Bigger is NOT better, and one should have several antennas to do different things. NO ONE ANTENNA WILL DO IT ALL!! Although the StepIR comes pretty damn close. but then we won't go into resonant antennas again, our experts on here don't like them, they rather use lossy devices.


ab8sw
bill
Reply to a comment by : W4EF on 2007-03-07

K9IUQ wrote: >>No argument about the above statement. The argument is a 130ft wire with open feeders will radiate better than a 32 ft coax fed dipole (or trapped dipole) on 20 mtrs.<< Ok, I see what you are driving at, Stan. I should have read your post more carefully. I stand by what I wrote, however, at least in terms of efficiency of radiation (power entering coax vs. power radiated by antenna into space). What you are talking about with the 130 foot open-wire antenna is directivity. Directivity is a "rob Peter to pay Paul" zero-sum-game phenomenon. The 130ft long antenna open wire fed antenna will have significantly more gain on 20 meters than the trap dipole, but mainly because it has significantly greater directivity, not because it has better efficiency. Gain is as Martha would say "a good thing" but only if it occurs in a desireable direction. Since directivity is "robbing Peter to pay Paul", you will be worse off in some directions with the 130ft open-wire fed antenna than with the trapped dipole. Maybe this is okay (say you want to keep a schedule and you point the lobe of the 130ft antenna at the person you have your schedule with), but for that reason it's important to make the distinction between efficiency improvements (net improvement in all directions) versus directivity improvements (net improvement in one direction(s) with an equal net penalty in some other direction(s)). 73, Mike W4EF.....................
Reply to a comment by : K9IUQ on 2007-03-07

W4EF says MILF_MAN is right in this case. A trapped dipole is most efficient on the highest band of operation since at that frequency, the radiator is more or less a full-size 1/2 wave radiator. .................................................... No argument about the above statement. The argument is a 130ft wire with open feeders will radiate better than a 32 ft coax fed dipole (or trapped dipole) on 20 mtrs. A 130ft antenna at 20 mtrs is 2 wavelengths long. Fed with open wire feeders this antenna will outperform a 32ft 20mtr wire dipole. This antenna will have gain in some directions over a dipole and the pattern will be much different than a dipole. The Idea is Actually pretty simple. Say you want to work HF mobile. What is going to radiate more RF and be more efficient? A 4ft whip or a 8.5 ft whip. Same idea with the 130 ft wire. It has more radiating area than a 32ft dipole and will be a better antenna. If bigger was not better we would all be using a rubber duck to transmit on hf. K9IUQ
W4EF2007-03-07
RE: Benchmarks
K9IUQ wrote:

>>No argument about the above statement. The argument is a 130ft wire with open feeders will radiate better than a 32 ft coax fed dipole (or trapped dipole) on 20 mtrs.<<

Ok, I see what you are driving at, Stan. I should have read your post more carefully. I stand by what I wrote, however, at least in terms of efficiency of radiation (power entering coax vs. power radiated by antenna into space). What you are talking about with the 130 foot open-wire antenna is directivity. Directivity is a "rob Peter to pay Paul" zero-sum-game phenomenon. The 130ft long antenna open wire fed antenna will have significantly more gain on 20 meters than the trap dipole, but mainly because it has significantly greater directivity, not because it has better efficiency. Gain is as Martha would say "a good thing" but only if it occurs in a desireable direction. Since directivity is "robbing Peter to pay Paul", you will be worse off in some directions with the 130ft open-wire fed antenna than with the trapped dipole. Maybe this is okay (say you want to keep a schedule and you point the lobe of the 130ft antenna at the person you have your schedule with), but for that reason it's important to make the distinction between efficiency improvements (net improvement in all directions) versus directivity improvements (net improvement in one direction(s) with an equal net penalty in some other direction(s)).

73, Mike W4EF.....................
Reply to a comment by : K9IUQ on 2007-03-07

W4EF says MILF_MAN is right in this case. A trapped dipole is most efficient on the highest band of operation since at that frequency, the radiator is more or less a full-size 1/2 wave radiator. .................................................... No argument about the above statement. The argument is a 130ft wire with open feeders will radiate better than a 32 ft coax fed dipole (or trapped dipole) on 20 mtrs. A 130ft antenna at 20 mtrs is 2 wavelengths long. Fed with open wire feeders this antenna will outperform a 32ft 20mtr wire dipole. This antenna will have gain in some directions over a dipole and the pattern will be much different than a dipole. The Idea is Actually pretty simple. Say you want to work HF mobile. What is going to radiate more RF and be more efficient? A 4ft whip or a 8.5 ft whip. Same idea with the 130 ft wire. It has more radiating area than a 32ft dipole and will be a better antenna. If bigger was not better we would all be using a rubber duck to transmit on hf. K9IUQ
KD2BD2007-03-07
RE: Benchmarks
K9IUQ wrote:

> The Idea is Actually pretty simple. Say you want to
> work HF mobile. What is going to radiate more RF and
> be more efficient? A 4ft whip or a 8.5 ft whip.
>
> Same idea with the 130 ft wire. It has more radiating
> area than a 32ft dipole and will be a better antenna.

Well, yes and no, Stan. :-)

If we could efficiently resonate the 32 foot dipole on 80 meters, its "radiating area" (effective capture area) would be very close to that of the full-sized dipole.

Recall the description I gave of a resonant dipole last week.

When a dipole is made electrically short, far less RF energy gets radiated when current flows along the conductor of the antenna because of the dipole's short length.

HOWEVER, since we're bringing the antenna into resonance, the energy applied to the antenna will continue to oscillate along the dipole, many, many times, radiating a little each cycle, until it is ALL eventually radiated into space.

The price we pay for the shortened length is bandwidth. Such an antenna would have a very high 'Q' as a result of the high amount of stored energy oscillating back and forth along its length.

Of course in real life we have ohmic losses to contend with, but if not for these losses, a 32 foot dipole or a 4 foot whip made to resonate at 3.5 MHz and fed with 100 watts would radiate 100 watts into space, just like a full-sized dipole.

Also remember that if not for heat losses, the worst resonant antenna we could ever make in life would have gain (and therefore, effective capture area) no worse than that of an isotropic radiator (-2.14 dBd).


73, de John, KD2BD
Reply to a comment by : K9IUQ on 2007-03-07

W4EF says MILF_MAN is right in this case. A trapped dipole is most efficient on the highest band of operation since at that frequency, the radiator is more or less a full-size 1/2 wave radiator. .................................................... No argument about the above statement. The argument is a 130ft wire with open feeders will radiate better than a 32 ft coax fed dipole (or trapped dipole) on 20 mtrs. A 130ft antenna at 20 mtrs is 2 wavelengths long. Fed with open wire feeders this antenna will outperform a 32ft 20mtr wire dipole. This antenna will have gain in some directions over a dipole and the pattern will be much different than a dipole. The Idea is Actually pretty simple. Say you want to work HF mobile. What is going to radiate more RF and be more efficient? A 4ft whip or a 8.5 ft whip. Same idea with the 130 ft wire. It has more radiating area than a 32ft dipole and will be a better antenna. If bigger was not better we would all be using a rubber duck to transmit on hf. K9IUQ
K9IUQ2007-03-07
Benchmarks
W4EF says MILF_MAN is right in this case. A trapped dipole is most efficient on the highest band of operation since at that frequency, the radiator is more or less a full-size 1/2 wave radiator.
....................................................

No argument about the above statement. The argument is a 130ft wire with open feeders will radiate better than a 32 ft coax fed dipole (or trapped dipole) on 20 mtrs.

A 130ft antenna at 20 mtrs is 2 wavelengths long. Fed with open wire feeders this antenna will outperform a 32ft 20mtr wire dipole.

This antenna will have gain in some directions over a dipole and the pattern will be much different than a dipole.

The Idea is Actually pretty simple. Say you want to work HF mobile. What is going to radiate more RF and be more efficient? A 4ft whip or a 8.5 ft whip.

Same idea with the 130 ft wire. It has more radiating area than a 32ft dipole and will be a better antenna.

If bigger was not better we would all be using a rubber duck to transmit on hf.

K9IUQ
W4EF2007-03-07
RE: Benchmarks
MILF_MAN EE wrote:

>> K9IQU says
only radiates 32ft of its length on 20 mtrs.

and thats just about the right length for a 1/2wave on 20m. whats wrong with that. oh thats right bigger is badder. <<


MILF_MAN is right in this case. A trapped dipole is most efficient on the highest band of operation since at that frequency, the radiator is more or less a full-size 1/2 wave radiator. As you go down in frequency each set of traps adds progressively more inductive loading, hence the significant shortening for operation on 80 meters (84 feet vs. 130). The radiation resistance of the trapped antenna on 80 meters will be significantly lower than a full size 1/2 wave dipole (I'm guessing 30 ohms free space versus 73 ohms free space). Nevertheless shortened 80 meter dipoles can work very well PROVIDED that the loading inductor Q is sufficiently high:

http://www.qsl.net/ve6wz/intro.htm

73, Mike W4EF.........
Reply to a comment by : MLMAN_EE on 2007-03-07

K9IQU says only radiates 32ft of its length on 20 mtrs. and thats just about the right length for a 1/2wave on 20m. whats wrong with that. oh thats right bigger is badder.
Reply to a comment by : MLMAN_EE on 2007-03-07

K9IQU says Antenna Strength = Bigger more wire area radiating, means bigger badder signals. Damn why did I was all that money, especially on my 2m antennas, i could have hooked it to my wire. acording to K9IQU bigger is badder. Now thats a wives tail! probably been telling that to your wife too. say goodnight K9IQU its your nap time. AB8SW bill happy now you grumpy old crusty fart. guess now i am smart.
Reply to a comment by : K9IUQ on 2007-03-07

Actually if traps are designed properly, just like your inductor coil in your tuner, they will have very little loss. ...................................................... Trapped wire antennas should be used only as a last resort. Consider this: A 84 ft trapped dipole only radiates 32ft of its length on 20 mtrs. What will give you a better signal 32ft of radiating trapped dipole fed with coax or 130ft (or 84ft)of wire fed with open feeders radiating ITS ENTIRE LENGTH. Even an anonymous dummy should be able to figure this one out. Antenna Strength = Bigger more wire area radiating, means bigger badder signals. I was once stupid enough to buy a trapped dipole and compare it to a 130 ft antenna fed with open feeders and tuner. The trapped dipole simply could not compete. K9IUQ
MLMAN_EE2007-03-07
RE: Benchmarks
K9IQU says
only radiates 32ft of its length on 20 mtrs.

and thats just about the right length for a 1/2wave on 20m. whats wrong with that. oh thats right bigger is badder.


Reply to a comment by : MLMAN_EE on 2007-03-07

K9IQU says Antenna Strength = Bigger more wire area radiating, means bigger badder signals. Damn why did I was all that money, especially on my 2m antennas, i could have hooked it to my wire. acording to K9IQU bigger is badder. Now thats a wives tail! probably been telling that to your wife too. say goodnight K9IQU its your nap time. AB8SW bill happy now you grumpy old crusty fart. guess now i am smart.
Reply to a comment by : K9IUQ on 2007-03-07

Actually if traps are designed properly, just like your inductor coil in your tuner, they will have very little loss. ...................................................... Trapped wire antennas should be used only as a last resort. Consider this: A 84 ft trapped dipole only radiates 32ft of its length on 20 mtrs. What will give you a better signal 32ft of radiating trapped dipole fed with coax or 130ft (or 84ft)of wire fed with open feeders radiating ITS ENTIRE LENGTH. Even an anonymous dummy should be able to figure this one out. Antenna Strength = Bigger more wire area radiating, means bigger badder signals. I was once stupid enough to buy a trapped dipole and compare it to a 130 ft antenna fed with open feeders and tuner. The trapped dipole simply could not compete. K9IUQ
MLMAN_EE2007-03-07
RE: Benchmarks
K9IQU says
Antenna Strength = Bigger more wire area radiating, means bigger badder signals.

Damn why did I was all that money, especially on my 2m antennas, i could have hooked it to my wire. acording to K9IQU bigger is badder. Now thats a wives tail! probably been telling that to your wife too.

say goodnight K9IQU its your nap time.

AB8SW
bill

happy now you grumpy old crusty fart. guess now i am smart.
Reply to a comment by : K9IUQ on 2007-03-07

Actually if traps are designed properly, just like your inductor coil in your tuner, they will have very little loss. ...................................................... Trapped wire antennas should be used only as a last resort. Consider this: A 84 ft trapped dipole only radiates 32ft of its length on 20 mtrs. What will give you a better signal 32ft of radiating trapped dipole fed with coax or 130ft (or 84ft)of wire fed with open feeders radiating ITS ENTIRE LENGTH. Even an anonymous dummy should be able to figure this one out. Antenna Strength = Bigger more wire area radiating, means bigger badder signals. I was once stupid enough to buy a trapped dipole and compare it to a 130 ft antenna fed with open feeders and tuner. The trapped dipole simply could not compete. K9IUQ
K9IUQ2007-03-07
Benchmarks
Actually if traps are designed properly, just like your inductor coil in your tuner, they will have very little loss.
......................................................

Trapped wire antennas should be used only as a last resort. Consider this: A 84 ft trapped dipole only radiates 32ft of its length on 20 mtrs.

What will give you a better signal 32ft of radiating trapped dipole fed with coax or 130ft (or 84ft)of wire fed with open feeders radiating ITS ENTIRE LENGTH. Even an anonymous dummy should be able to figure this one out.

Antenna Strength = Bigger more wire area radiating, means bigger badder signals.


I was once stupid enough to buy a trapped dipole and compare it to a 130 ft antenna fed with open feeders and tuner. The trapped dipole simply could not compete.

K9IUQ




MLMAN_EE2007-03-07
RE: Benchmarks
why is that K9IUQ? I know lots of smart people without ham calls. Doctors, lawyers,engineers. does having a ham call make you smart? it didn't seem to help your tiny little feeble mind K9IUQ. or is it that you are just an old fart set in his ways and cant accept change as the world leaves him behind.
wakeup K9IUQ the world has left you behind and no one cares what you have to say. yes i am retired but i am only 45 still young enough to go with the flow. new ways and new days ahead. taking a good crap is probably the highlight of you day.

bill
Reply to a comment by : K9IUQ on 2007-03-07

K9IUQ says responding to stupid dumb anonymous posters are a complete waste of bandwidth. If one does not have enough conviction of their facts to Post with a REAL Ham Call then any ideas that they have are worthless.. K9IUQ
K9IUQ2007-03-07
Benchmarks
K9IUQ says responding to stupid dumb anonymous posters are a complete waste of bandwidth. If one does not have enough conviction of their facts to Post with a REAL Ham Call then any ideas that they have are worthless..

K9IUQ
MLMAN_EE2007-03-07
RE: Benchmarks
do you think your antenna gain and different radiation patterns as you change bands is equal to or greater then your loss?

I might be a dumb mailman, but I got a damn nice retirement and great government benies. I do have an ICOM 7800, a StepIR beam on a 64' tower, with cut to frquency wires for 80/40m. The stepIr will do everything else, and is the exact lengthe for each frequency. All antennas are fed with 1/2" hardline.
If i need more fire in the wire, I can fire up my alpha 99.

bill
Reply to a comment by : K9IUQ on 2007-03-07

Stupid dumb mailman-nonham or Ham afraid to post his Call says: 84' is easier to fit on city lots then 130'. ....................................................... Open Wire Feedline and tuner doesnt care how long an antenna is. A good tuner will resonate the SYSTEM. In Actual practice antennas shorter than 130ft will work quite well. Certainly a 84ft antenna fed with open feeders and tuner will work better than a 84 ft trapped dipole fed with coax. K9IUQ (Notice my Call. I choose not to be anonymous because I dont post unbelievable CRAP)
K9IUQ2007-03-07
Benchmarks
Stupid dumb mailman-nonham or Ham afraid to post his Call says:

84' is easier to fit on city lots then 130'.

.......................................................
Open Wire Feedline and tuner doesnt care how long an antenna is. A good tuner will resonate the SYSTEM.

In Actual practice antennas shorter than 130ft will work quite well. Certainly a 84ft antenna fed with open feeders and tuner will work better than a 84 ft trapped dipole fed with coax.

K9IUQ (Notice my Call. I choose not to be anonymous because I dont post unbelievable CRAP)
K9IUQ2007-03-07
Benchmarks
Stupid dumb mailman-nonham or Ham afraid to post his Call says:

This is fine if its your benchmark. Actually if traps are designed properly, just like your inductor coil in your tuner,

.......................................................
Ahh, but consider this. A 130 ft wire fed with open wire feeedline is LONGER than a dipole on all bands above 40 mtrs. This means it will have GAIN above any DIPOLE on all bands 40 mtrs and above. The higher the band, the more the gain. This is not my opinion but a fact that can be found by reading any basic antenna book. OR BETTER yet model the 130 ft antenna in EZNEC software as I have done many times. The results will surprise you, especially since you *think* a trap dipole is a better antenna.

AND this antenna wil work just fine on 60 and 30 mtrs. Try that with a trapped dipole...

K9IUQ
MLMAN_EE2007-03-07
RE: Benchmarks
Stan K9IUQ says
Add to this If you want a multiband *wire* antenna use openwire feedline AND a tuner. Forget Coax. Forget G5RV.Forget Trapped Antennas.Forget Fanned Dipoles. A 130 ft wire fed with open wire feedline will outperfom other multiband single wire antennas 80-10 mtrs........

This is fine if its your benchmark. Actually if traps are designed properly, just like your inductor coil in your tuner, they will have very little loss. Just use large diameter wire, large coil forms, and good quality caps. Then you can forget the tuner, feed with low loss coax directly to your rig. then you only need an 84' wire for all 5 major bands, and 15m is close enough for 17m. with the traps you are actually tuning your antenna, before the feed line. 84' is easier to fit on city lots then 130'.

bill


Reply to a comment by : K9IUQ on 2007-03-07

N3OX says Let's break this down to its very simple, objective conclusion. Putting up a dipole fed with 100' of RG-8X and a cheap MFJ tuner and using it on all bands will give you a weak signal. That's a fact. .......................................................... Add to this If you want a multiband *wire* antenna use openwire feedline AND a tuner. Forget Coax. Forget G5RV.Forget Trapped Antennas.Forget Fanned Dipoles. A 130 ft wire fed with open wire feedline will outperfom other multiband single wire antennas 80-10 mtrs........ Stan K9IUQ
K9IUQ2007-03-07
Benchmarks
N3OX says
Let's break this down to its very simple, objective conclusion.

Putting up a dipole fed with 100' of RG-8X and a cheap MFJ tuner and using it on all bands will give you a weak signal.

That's a fact.
..........................................................

Add to this If you want a multiband *wire* antenna use openwire feedline AND a tuner. Forget Coax. Forget G5RV.Forget Trapped Antennas.Forget Fanned Dipoles.

A 130 ft wire fed with open wire feedline will outperfom other multiband single wire antennas 80-10 mtrs........

Stan K9IUQ
MLMAN_EE2007-03-07
RE: Benchmarks
I do not know W4LGh, but I did like what he was saying. When he said he was not going to post anymore, i figured out his password, was to easy. actually and very easy to figure out just about anybodies password on here. I am a retired mailman with nothing but time on my hand.
Bill
Reply to a comment by : W8JII on 2007-03-07

To MLMAN EE/W4LGH:"You guys have done more to HURT amateur radio by making up these "perfect" examples on installs and making a bunch of hams think its ok to do this, when they have QRP levels being radiated. And its too late now, the damage has been done, they don't know who to believe anymore. So I sincerely hope all you you are very happy with yourselves and feel good about your super knowledge. " Actually it's very simple----No damage done just follow any and all advice given by KD2BD, W8JI and N3OX...... Oh yeah MLMAN EE/ w4LGH--can you spell schizophrenia?
Reply to a comment by : MLMAN_EE on 2007-03-06

Its an OK "make due" a band-aid sorta speak. everyone want to continue to use the best of the best, and MOST out there don't have the best of the best. How about the guy who has 150' of RG-8X or worse, RG-58 running to his 80m dipole. Thats a lot of loss! It is also the more typical example out there. Not everyone has the luxury of short, low loss coax runs. You guys have done more to HURT amateur radio by making up these "perfect" examples on installs and making a bunch of hams think its ok to do this, when they have QRP levels being radiated. And its too late now, the damage has been done, they don't know who to believe anymore. So I sincerely hope all you you are very happy with yourselves and feel good about your super knowledge. A simple parallel dipole, which is no more than a log periodic antenna is a very good antenna, easy to build, and you can set it up with the bands you want, or all of them. Uwe 100' or less RG8X or better, no tuner, and you'll get more power in the air, and better receive, and spend less money. these hams with 4 letters in their calls need to start thinking outside the box! Ham radio around the country isn't what it is at your house. Not all hams can afford to buy IC-7800's, 100foot towers, 7/8" hardline, and the big StepIR antennas.
Reply to a comment by : N3OX on 2007-03-05

Dipole cut for resonance at 3.53MHz, 50+j0 impedance at 3.9MHz is 75+j188, an SWR on 50 ohm line of 9.87. Total loss in 40 feet of RG-213 at this frequency and mismatch, 0.55dB. Total loss in the W9CF tuner simulator to match the 5-j14 impedance at the shack end of the coax, 1.8dB. That's 2.3dB total loss in the tuner plus the coax with a Q=100 coil in the tuner. What's 2.3dB on 75m phone? You think that matters much? It's the simplest way to stretch your 80m dipole to cover the whole band. - - - - - - There are plenty of examples that can be cooked up where the tuner at the shack end of the coax loses 3dB or 7dB or 12dB, but all it takes is one little counterexample... Dan
Reply to a comment by : MLMAN_EE on 2007-03-05

Geez...how would they know what was in your tuner? do you have some special built tuner with magical dilithum crystals? Its a basic T-Network tuner, vari. cap on input, hooked to an inductor, with a vari. cap on the output. The bigger the inductor the better, but I doubt you have a 1' diameter inductor in your box. 3db is pretty serious loss and thats before any type of line loss, and/or antenna loss. Coax adds insult to injury, open lead probably won't add to much more, but still some. QRP man! But that is ok, as you can work the world with QRP, but you sure are wasting a lot of power getting to your lossy antenna system. PUT MORE FIRE INTO THE WIRE, BYPASS THAT DAMN TUNER!
Reply to a comment by : N4KC on 2007-03-05

Man! These guys are good! Not only do they have a nice interactive website, with knobs you can crank and everything, but they also know what the loss is in MY tuner! How do they do that? How do they know what kind of components are in MY tuner? Or what the inductor (the primary source of loss) is inside MY tuner? The things they can do with cookies these days! Maybe they can also tell me the temperature in MY freezer so my spumoni won't get soft! Don N4KC www.donkeith.com/n4kc.htm
Reply to a comment by : MLMAN_EE on 2007-03-05

Here is a GREAT link that will actually show you what the losses are in your tuner, located in your shack. It is an actual T network tuner, you can spin the knobs and actually tune it. In the upper left hand corner it will show you you actual loss. I think a lot of will be surprised at what the losses REALLY are! 2 to 8DB loss in the tuner. Shows what W4LGH was talking about. Now take this loss in your tuner, then if using COAX add in that loss, then the loss of you antenna not being resonant, and what are you doing... Sounds a little ABSURD to me to use a tuner hooked to coax in your shack. Unless you are happy running QRP all the time, because thats what you are doing. Check out the link and see for yourself... http://fermi.la.asu.edu/w9cf/tuner/tuner.html Lifes to short to run QRP!
Reply to a comment by : W4EF on 2007-03-04

K9MI >> But if I'm using an antenna made for the band I'm using, but not the portion of the band, I can still have a fairly high swr, make the rig happy and work the dx. How much loss do I have with 85 ft of RG-213 at a 4:1 swr. Probably not that much. But a tuner/transmatch/coupler/impedance matching device is a necessary evil to keep my solid state rig happy. << It depends a little bit on the phase angle of the impedance at the antenna terminals, but per N6BV's TLW, the additional loss due to the 4:1 mis-match on the coax will be a whopping 0.5 dB (~10% of the incident power)!! There will be a bit more loss in the tuner (mostly in the inductor), but probably not much more than 0.1dB. So you are talking about what roughly amounts to a 0.6dB compromise in the system efficiency by tuning from the shack. Your rig if it uses a solid state final PA probably puts out at least 6dB more power when it sees a good match vs 4:1, so in terms of using the tuner in the shack versus doing nothing at all, you are likely getting a 5 or 6 dB net improvement by using the tuner. The biggest performance factor, of course, will be how the pattern of the yagi changes as you go from SSB down to CW. Without some modeling, that's anybody's guess (could be worse, could be better, could be the same). Also it could be better in terms of gain, but worse in terms of sidelobes, or vice versa. Mike, your situtation of using a tribander tuned for SSB in the CW segment of band with a solid state rig is a perfect example of where using a tuner in the shack makes decent sense. 73, Mike W4EF..................................
Reply to a comment by : K9MI on 2007-03-03

A very lively and intense subject! What I do know, is that my run of the mill, 3 element tribander was assembled for the phone band. By the time I get into the lower portion of the cw band, my swr is 4:1, maybe more. With the use of an outboard tuner, it can be adjusted to where my solid state rig is now looking at a 1:1 match, not the 4:1 plus match. More then likely, the person with an antenna of the same variety is louder to the dx station then I am. Maybe not. Is my swr still 4:1? Yep. But if I'm using an antenna made for the band I'm using, but not the portion of the band, I can still have a fairly high swr, make the rig happy and work the dx. How much loss do I have with 85 ft of RG-213 at a 4:1 swr. Probably not that much. But a tuner/transmatch/coupler/impedance matching device is a necessary evil to keep my solid state rig happy. The bottom line is all I have done is make my solid state rig happy. And, I work the dx with no trouble. I'm referring to using an antenna that is made for that band. Do I still have the high swr? Sure, but I have made my rig happy and worked the dx. Is this ideal? No, but those of us that work from one end of the band to another know there are very few antenna farms the average ham can afford, or have room for, that allows that luxury. A 75m dipole fed with coax is IMO a poor choice as a multi band antenna. Feed it with 450 ohm ladder line, and you at least have your power reaching the antenna. You'll get some weird lobes, but an antenna like that is still decent (not perfect) between 75 & 20 meters. In other words, yes a resonante antenna would be great to have on all bands and all frequencies. Very few of us have that situation so you do the best you can with what you have. What is really funny to hear, or maybe sad depending on how you look at it, is to hear someone on 75 meters talking about how much better he would probably get out when he trims his dipole to get a 1:1 match instead of the 1.5:1 he has now! I don't have time to read all the responses on here, as I have other things in life that have to be done. Do the best you can with your antenna system, but don't be afraid to step out of the box either. A little! All my comments pertain to HF not VHF/UHF! 73 and enjoy ham radio! Mike, K9MI
W8JII2007-03-07
RE: Benchmarks
To MLMAN EE/W4LGH:"You guys have done more to HURT amateur radio by making up these "perfect" examples on installs and making a bunch of hams think its ok to do this, when they have QRP levels being radiated.

And its too late now, the damage has been done, they don't know who to believe anymore. So I sincerely hope all you you are very happy with yourselves and feel good about your super knowledge. "


Actually it's very simple----No damage done just follow any and all advice given by KD2BD, W8JI and N3OX......

Oh yeah MLMAN EE/ w4LGH--can you spell schizophrenia?
Reply to a comment by : MLMAN_EE on 2007-03-06

Its an OK "make due" a band-aid sorta speak. everyone want to continue to use the best of the best, and MOST out there don't have the best of the best. How about the guy who has 150' of RG-8X or worse, RG-58 running to his 80m dipole. Thats a lot of loss! It is also the more typical example out there. Not everyone has the luxury of short, low loss coax runs. You guys have done more to HURT amateur radio by making up these "perfect" examples on installs and making a bunch of hams think its ok to do this, when they have QRP levels being radiated. And its too late now, the damage has been done, they don't know who to believe anymore. So I sincerely hope all you you are very happy with yourselves and feel good about your super knowledge. A simple parallel dipole, which is no more than a log periodic antenna is a very good antenna, easy to build, and you can set it up with the bands you want, or all of them. Uwe 100' or less RG8X or better, no tuner, and you'll get more power in the air, and better receive, and spend less money. these hams with 4 letters in their calls need to start thinking outside the box! Ham radio around the country isn't what it is at your house. Not all hams can afford to buy IC-7800's, 100foot towers, 7/8" hardline, and the big StepIR antennas.
Reply to a comment by : N3OX on 2007-03-05

Dipole cut for resonance at 3.53MHz, 50+j0 impedance at 3.9MHz is 75+j188, an SWR on 50 ohm line of 9.87. Total loss in 40 feet of RG-213 at this frequency and mismatch, 0.55dB. Total loss in the W9CF tuner simulator to match the 5-j14 impedance at the shack end of the coax, 1.8dB. That's 2.3dB total loss in the tuner plus the coax with a Q=100 coil in the tuner. What's 2.3dB on 75m phone? You think that matters much? It's the simplest way to stretch your 80m dipole to cover the whole band. - - - - - - There are plenty of examples that can be cooked up where the tuner at the shack end of the coax loses 3dB or 7dB or 12dB, but all it takes is one little counterexample... Dan
Reply to a comment by : MLMAN_EE on 2007-03-05

Geez...how would they know what was in your tuner? do you have some special built tuner with magical dilithum crystals? Its a basic T-Network tuner, vari. cap on input, hooked to an inductor, with a vari. cap on the output. The bigger the inductor the better, but I doubt you have a 1' diameter inductor in your box. 3db is pretty serious loss and thats before any type of line loss, and/or antenna loss. Coax adds insult to injury, open lead probably won't add to much more, but still some. QRP man! But that is ok, as you can work the world with QRP, but you sure are wasting a lot of power getting to your lossy antenna system. PUT MORE FIRE INTO THE WIRE, BYPASS THAT DAMN TUNER!
Reply to a comment by : N4KC on 2007-03-05

Man! These guys are good! Not only do they have a nice interactive website, with knobs you can crank and everything, but they also know what the loss is in MY tuner! How do they do that? How do they know what kind of components are in MY tuner? Or what the inductor (the primary source of loss) is inside MY tuner? The things they can do with cookies these days! Maybe they can also tell me the temperature in MY freezer so my spumoni won't get soft! Don N4KC www.donkeith.com/n4kc.htm
Reply to a comment by : MLMAN_EE on 2007-03-05

Here is a GREAT link that will actually show you what the losses are in your tuner, located in your shack. It is an actual T network tuner, you can spin the knobs and actually tune it. In the upper left hand corner it will show you you actual loss. I think a lot of will be surprised at what the losses REALLY are! 2 to 8DB loss in the tuner. Shows what W4LGH was talking about. Now take this loss in your tuner, then if using COAX add in that loss, then the loss of you antenna not being resonant, and what are you doing... Sounds a little ABSURD to me to use a tuner hooked to coax in your shack. Unless you are happy running QRP all the time, because thats what you are doing. Check out the link and see for yourself... http://fermi.la.asu.edu/w9cf/tuner/tuner.html Lifes to short to run QRP!
Reply to a comment by : W4EF on 2007-03-04

K9MI >> But if I'm using an antenna made for the band I'm using, but not the portion of the band, I can still have a fairly high swr, make the rig happy and work the dx. How much loss do I have with 85 ft of RG-213 at a 4:1 swr. Probably not that much. But a tuner/transmatch/coupler/impedance matching device is a necessary evil to keep my solid state rig happy. << It depends a little bit on the phase angle of the impedance at the antenna terminals, but per N6BV's TLW, the additional loss due to the 4:1 mis-match on the coax will be a whopping 0.5 dB (~10% of the incident power)!! There will be a bit more loss in the tuner (mostly in the inductor), but probably not much more than 0.1dB. So you are talking about what roughly amounts to a 0.6dB compromise in the system efficiency by tuning from the shack. Your rig if it uses a solid state final PA probably puts out at least 6dB more power when it sees a good match vs 4:1, so in terms of using the tuner in the shack versus doing nothing at all, you are likely getting a 5 or 6 dB net improvement by using the tuner. The biggest performance factor, of course, will be how the pattern of the yagi changes as you go from SSB down to CW. Without some modeling, that's anybody's guess (could be worse, could be better, could be the same). Also it could be better in terms of gain, but worse in terms of sidelobes, or vice versa. Mike, your situtation of using a tribander tuned for SSB in the CW segment of band with a solid state rig is a perfect example of where using a tuner in the shack makes decent sense. 73, Mike W4EF..................................
Reply to a comment by : K9MI on 2007-03-03

A very lively and intense subject! What I do know, is that my run of the mill, 3 element tribander was assembled for the phone band. By the time I get into the lower portion of the cw band, my swr is 4:1, maybe more. With the use of an outboard tuner, it can be adjusted to where my solid state rig is now looking at a 1:1 match, not the 4:1 plus match. More then likely, the person with an antenna of the same variety is louder to the dx station then I am. Maybe not. Is my swr still 4:1? Yep. But if I'm using an antenna made for the band I'm using, but not the portion of the band, I can still have a fairly high swr, make the rig happy and work the dx. How much loss do I have with 85 ft of RG-213 at a 4:1 swr. Probably not that much. But a tuner/transmatch/coupler/impedance matching device is a necessary evil to keep my solid state rig happy. The bottom line is all I have done is make my solid state rig happy. And, I work the dx with no trouble. I'm referring to using an antenna that is made for that band. Do I still have the high swr? Sure, but I have made my rig happy and worked the dx. Is this ideal? No, but those of us that work from one end of the band to another know there are very few antenna farms the average ham can afford, or have room for, that allows that luxury. A 75m dipole fed with coax is IMO a poor choice as a multi band antenna. Feed it with 450 ohm ladder line, and you at least have your power reaching the antenna. You'll get some weird lobes, but an antenna like that is still decent (not perfect) between 75 & 20 meters. In other words, yes a resonante antenna would be great to have on all bands and all frequencies. Very few of us have that situation so you do the best you can with what you have. What is really funny to hear, or maybe sad depending on how you look at it, is to hear someone on 75 meters talking about how much better he would probably get out when he trims his dipole to get a 1:1 match instead of the 1.5:1 he has now! I don't have time to read all the responses on here, as I have other things in life that have to be done. Do the best you can with your antenna system, but don't be afraid to step out of the box either. A little! All my comments pertain to HF not VHF/UHF! 73 and enjoy ham radio! Mike, K9MI
N3OX2007-03-06
RE: Benchmarks
K9IUQ writes:

"have a solid state ALS-600 amp that will NOT tolerate a 2:1 SWR. I use a Ten-Tec 238B Tuner. Never Have I worried about using the tuner. I have bypassed the tuner and then put the tuner in line and NEVER has it made ANY difference in reception of a signal. "

You know what you're doing ;-) My point is just that I'd rather have an extra 3dB from the weak DX station I'm listening to.

W4LGH writes: "Don't acuse me of being mlman_ee's twin. I have no idea who he/she is"

Bull. You must really think we're stupid. Someone stole YOUR password to post IN SUPPORT OF WHAT YOU WERE SAYING instead of stealing MINE or KD2BD's or K9IUQ's. Maybe stealing N2MG's password... he's the webmaster, after all...

Durrrrh... I belierve you thar W4Lgh... I just got on them intarweb annI know thar's a hackars alwais steelin yoor eHam passwards...

- - - - - -

C'mon, there's only a couple more days of this article on the front page, I'm sure... can we set a record? Can we keep this thing going EVEN AFTER IT'S GONE OFF THE FRONT PAGE?!

The great eHam resonance holy war...

- - - - - -

Let's break this down to its very simple, objective conclusion.

Putting up a dipole fed with 100' of RG-8X and a cheap MFJ tuner and using it on all bands will give you a weak signal.

That's a fact.

Putting up an 80m dipole fed with 100' of LMR-400 and using a *good* tuner to stretch it across the band will likely drop less than 1dB in tuner and coax.

Also a fact.

Let people learn that they'll be piss weak if their antenna system is bad. Don't tell them it's because their antenna is not resonant or some other quasi-physics.

Dan
Reply to a comment by : W4LGH on 2007-03-06

N3OX wrote~"That said, an active DXer is going to figure out that every dB counts and doesn't need W4LGH/MLMAN_EE's twin abusive personality to help him or her figure out that they might want to put up a beam instead of a random coax-fed dipole and small MFJ tuner. ;-)"~ Don't acuse me of being mlman_ee's twin. I have no idea who he/she is. I said I was NOT going to post in this thread anymore sometime back and I see while I was in NYC working, someone hacked my password. I don't know who, this MLMAN-EE says it was he, I have no idea! I have been in contact with eHam, and all my passwords have been changed. IN any event, I want all, or as much as I can get of my power to the antenna. I do NOT use a tuner of any kind and I feed my antennas with 100' of LMR-400 wire. Yall do what you want, just get on the air! 73 de W4LGH Alan http://www.w4lgh.com
Reply to a comment by : K9IUQ on 2007-03-06

N3OX says That said, an active DXer is going to figure out that every dB counts ..................................................... I am an Active Dxer, work 6-10 dx stations EVERY day. I use a Log Periodic Beam Antenna. My Log has mostly a 2:1 SWR thruout the freq range of 14-30mhz. I have a solid state ALS-600 amp that will NOT tolerate a 2:1 SWR. I use a Ten-Tec 238B Tuner. Never Have I worried about using the tuner. I have bypassed the tuner and then put the tuner in line and NEVER has it made ANY difference in reception of a signal. I conclude then that this active DXER is not losing any DX because of his tuner. Stan K9IUQ
W4LGH2007-03-06
RE: Benchmarks
N3OX wrote~"That said, an active DXer is going to figure out that every dB counts and doesn't need W4LGH/MLMAN_EE's twin abusive personality to help him or her figure out that they might want to put up a beam instead of a random coax-fed dipole and small MFJ tuner. ;-)"~

Don't acuse me of being mlman_ee's twin. I have no idea who he/she is. I said I was NOT going to post in this thread anymore sometime back and I see while I was in NYC working, someone hacked my password. I don't know who, this MLMAN-EE says it was he, I have no idea! I have been in contact with eHam, and all my passwords have been changed.

IN any event, I want all, or as much as I can get of my power to the antenna. I do NOT use a tuner of any kind and I feed my antennas with 100' of LMR-400 wire. Yall do what you want, just get on the air!

73 de W4LGH Alan
http://www.w4lgh.com

Reply to a comment by : K9IUQ on 2007-03-06

N3OX says That said, an active DXer is going to figure out that every dB counts ..................................................... I am an Active Dxer, work 6-10 dx stations EVERY day. I use a Log Periodic Beam Antenna. My Log has mostly a 2:1 SWR thruout the freq range of 14-30mhz. I have a solid state ALS-600 amp that will NOT tolerate a 2:1 SWR. I use a Ten-Tec 238B Tuner. Never Have I worried about using the tuner. I have bypassed the tuner and then put the tuner in line and NEVER has it made ANY difference in reception of a signal. I conclude then that this active DXER is not losing any DX because of his tuner. Stan K9IUQ
K9IUQ2007-03-06
Benchmarks
N3OX says That said, an active DXer is going to figure out that every dB counts

.....................................................
I am an Active Dxer, work 6-10 dx stations EVERY day.
I use a Log Periodic Beam Antenna. My Log has mostly a 2:1 SWR thruout the freq range of 14-30mhz.

I have a solid state ALS-600 amp that will NOT tolerate a 2:1 SWR. I use a Ten-Tec 238B Tuner. Never Have I worried about using the tuner. I have bypassed the tuner and then put the tuner in line and NEVER has it made ANY difference in reception of a signal.

I conclude then that this active DXER is not losing any DX because of his tuner.

Stan K9IUQ
KD2BD2007-03-06
RE: Benchmarks
N3OX wrote:

> He's contributed excellent information to this thread,

Thanks, Dan. :-)

> W8JI's measurements suggest Miniductors are around Q=200-300 for the smaller ones.

> http://w8ji.com/loading_inductors.htm

Good to know. Thanks!

K9IUQ wrote:

> So High Quality does not necessarily equate to low loss.

Very true, Stan.

The ARRL Lab tested the old Johnson Kilowatt and smaller version tuners a number of years ago. (The results may be in the article you pointed out.)

They found the smaller tuner actually had less loss than the larger KW version.


73, de John, KD2BD
Reply to a comment by : N3OX on 2007-03-06

"I never measured the Q of the coil, but I have some old "Miniductor" made with smaller diameter wire, and its Q (measured with an old Heathkit Q Meter) is *at least* 200. (That's just a guess. I know it pins the meter on its highest range.)" W8JI's measurements suggest Miniductors are around Q=200-300 for the smaller ones. http://w8ji.com/loading_inductors.htm A big part of the problem really is the output caps when used on too-short antennas. My little MFJ that went all molten on me had 250pF caps. Full mesh on 80m still inserts 180 ohms of cap. reactance in series with the already highly capacitive antenna reactance (everyone puts up a too-short antenna on the low bands, right?). Just bypassing the output capacitor entirely and using the network as a step-up L match would have almost certainly solved the problem, but this was a couple of months into my General class license in '96 or so, and I didn't know anything about impedance matching. Those who are interested can see the effect by putting a huge capacitance in for the output capacitor in W9CF's simulator and putting in something like 10-j500 for the input impedance. The autotuner will take the capacitor to maximum, even if you put in something like 10 million pF! Yes, 10 microfarads. Dan
Reply to a comment by : N3OX on 2007-03-06

Oh, and don't go using my report of doing something stupid with a cheap-ass tuner against KD2BD. He's contributed excellent information to this thread, you've just muddied the waters and caused trouble. It is possible with a cheap T-network tuner to get solder-melting inductor temperatures, especially on low frequencies when you have to match a more extreme impedance because the antenna capacitor won't go below a couple hundred ohms reactance. However, at the time, I was using LADDERLINE between the tuner and the antenna and getting VERY GOOD SIGNAL REPORTS. I could work DX, I could make all sorts of contacts around the states. Clearly I was dropping some tens of watts in the tuner, but it wasn't destroying my ability to enjoy 80m operation, and I was hardly a F*$(#(%* idiot for getting on the air with that tuner on SSB or CW and having some fun and making some contacts. It didn't matter that I might have been losing 3dB in the tuner!!! Dan
Reply to a comment by : N3OX on 2007-03-06

"So are we in agreement here, that using a Palstar top of the line tuner, hooked to 7/8" andrew cable hooked to a random length dipole might not have a lot of loss, but still has loss? But the same senario using a cheap MFJ tuner hooked to RG8X might be a waste of time do to serious losses?" Yeah, like that's really what you said the first time... Gawd. Glad it took three weeks and who knows how many posts to get you to admit that it DEPENDS ON THE SITUATION. Dan
Reply to a comment by : MLMAN_EE on 2007-03-06

My point exactly! More MFJ tuners out there than any others. Most hams won't spend $600 for a nice tuner, or a buck a foot for good wire! So there you go KB2DB...your answer is YES it will get that HOT! One must remember when running ssb the duty cycle isn't that high. Hold a CW carrier thru your tuner for , oh lets say 3 minutes... then try to touch your inductor coil. Does anyone know the Q of their inductor coil in their tuner? I have never seen this specified in any ads. So are we in agreement here, that using a Palstar top of the line tuner, hooked to 7/8" andrew cable hooked to a random length dipole might not have a lot of loss, but still has loss? But the same senario using a cheap MFJ tuner hooked to RG8X might be a waste of time do to serious losses? think outside the box guys!
Reply to a comment by : N3OX on 2007-03-06

"If 100 watts were applied to the tuner for 5 solid minutes, would the coil get as hot as if we applied a 40 watt soldering iron to it for the same length of time? " If you're using a crappy Q=100 inductor and too-small caps in your tuner as you might be in a cheap MFJ tuner, yeah, it probably would. It bears mentioning that if you change the W9CF tuner parameters to something better, say 350pF caps and a Q=200 coil to get closer to what you might have in a nice high power tuner, you get a tuner loss of about half a dB. I caused a failure of a MFJ "300W" tuner by running 100W RTTY into a significant mismatch on 80m. The failure mode was to melt the styrene coil spacers AND it got hot enough to solder two turns together! I think W9CF's default tuner parameters are set to default to bottom-of-the-line MFJ low-power tuner. Dan
Reply to a comment by : MLMAN_EE on 2007-03-06

>KD2BD says, If 100 watts were applied to the tuner >for 5 solid minutes, would the coil get as hot as if >we applied a 40 watt soldering iron to it for the >same length of time? Gee, this was taken directly from an MFJ ad, >New Cabinet maintains high Q >New roomy cabinet helps maintain components’ high Q. >Vent holes help keep components cool. Wouldn't that last statement be taken to mean there is going to be heat? Next time you finish a QSO on your tuner, pop the top off and see if you can place your fingers on the inductor. You need to have it ready for quick access as it will cool, or radiate the energy that didn't make it to your antenna, pretty quickly. You can also try the same with your tank circuit in your amp too, BUT turn the POWER off first!! And also doesn't your solid-state rig has a fan on it? Mine does and heat pours out, where do you think this heat is coming from? Sure the transistors get warm, but so does the tank circuit there too. >CQ COMMON SENSE CALLING CQ COMMON SENSE Exactly!
Reply to a comment by : KD2BD on 2007-03-06

N3OX wrote: > Total loss in the W9CF tuner simulator to match the 5-j14 impedance at the shack end of the coax, 1.8dB. That still seems pretty excessive, Dan. That's 34 watts of RF lost to heat for every 100 watts applied. Wow! If 100 watts were applied to the tuner for 5 solid minutes, would the coil get as hot as if we applied a 40 watt soldering iron to it for the same length of time? And think about the inductor in your tube final's Pi Network, and ALL the inductors in the final stage of your solid state transmitter. Should we eliminate those, too? Maybe we've all been running QRP the whole time. CQ COMMON SENSE CALLING CQ COMMON SENSE... :-) 73, de John, KD2BD
Reply to a comment by : N3OX on 2007-03-05

Dipole cut for resonance at 3.53MHz, 50+j0 impedance at 3.9MHz is 75+j188, an SWR on 50 ohm line of 9.87. Total loss in 40 feet of RG-213 at this frequency and mismatch, 0.55dB. Total loss in the W9CF tuner simulator to match the 5-j14 impedance at the shack end of the coax, 1.8dB. That's 2.3dB total loss in the tuner plus the coax with a Q=100 coil in the tuner. What's 2.3dB on 75m phone? You think that matters much? It's the simplest way to stretch your 80m dipole to cover the whole band. - - - - - - There are plenty of examples that can be cooked up where the tuner at the shack end of the coax loses 3dB or 7dB or 12dB, but all it takes is one little counterexample... Dan
Reply to a comment by : MLMAN_EE on 2007-03-05

Geez...how would they know what was in your tuner? do you have some special built tuner with magical dilithum crystals? Its a basic T-Network tuner, vari. cap on input, hooked to an inductor, with a vari. cap on the output. The bigger the inductor the better, but I doubt you have a 1' diameter inductor in your box. 3db is pretty serious loss and thats before any type of line loss, and/or antenna loss. Coax adds insult to injury, open lead probably won't add to much more, but still some. QRP man! But that is ok, as you can work the world with QRP, but you sure are wasting a lot of power getting to your lossy antenna system. PUT MORE FIRE INTO THE WIRE, BYPASS THAT DAMN TUNER!
Reply to a comment by : N4KC on 2007-03-05

Man! These guys are good! Not only do they have a nice interactive website, with knobs you can crank and everything, but they also know what the loss is in MY tuner! How do they do that? How do they know what kind of components are in MY tuner? Or what the inductor (the primary source of loss) is inside MY tuner? The things they can do with cookies these days! Maybe they can also tell me the temperature in MY freezer so my spumoni won't get soft! Don N4KC www.donkeith.com/n4kc.htm
Reply to a comment by : MLMAN_EE on 2007-03-05

Here is a GREAT link that will actually show you what the losses are in your tuner, located in your shack. It is an actual T network tuner, you can spin the knobs and actually tune it. In the upper left hand corner it will show you you actual loss. I think a lot of will be surprised at what the losses REALLY are! 2 to 8DB loss in the tuner. Shows what W4LGH was talking about. Now take this loss in your tuner, then if using COAX add in that loss, then the loss of you antenna not being resonant, and what are you doing... Sounds a little ABSURD to me to use a tuner hooked to coax in your shack. Unless you are happy running QRP all the time, because thats what you are doing. Check out the link and see for yourself... http://fermi.la.asu.edu/w9cf/tuner/tuner.html Lifes to short to run QRP!
Reply to a comment by : W4EF on 2007-03-04

K9MI >> But if I'm using an antenna made for the band I'm using, but not the portion of the band, I can still have a fairly high swr, make the rig happy and work the dx. How much loss do I have with 85 ft of RG-213 at a 4:1 swr. Probably not that much. But a tuner/transmatch/coupler/impedance matching device is a necessary evil to keep my solid state rig happy. << It depends a little bit on the phase angle of the impedance at the antenna terminals, but per N6BV's TLW, the additional loss due to the 4:1 mis-match on the coax will be a whopping 0.5 dB (~10% of the incident power)!! There will be a bit more loss in the tuner (mostly in the inductor), but probably not much more than 0.1dB. So you are talking about what roughly amounts to a 0.6dB compromise in the system efficiency by tuning from the shack. Your rig if it uses a solid state final PA probably puts out at least 6dB more power when it sees a good match vs 4:1, so in terms of using the tuner in the shack versus doing nothing at all, you are likely getting a 5 or 6 dB net improvement by using the tuner. The biggest performance factor, of course, will be how the pattern of the yagi changes as you go from SSB down to CW. Without some modeling, that's anybody's guess (could be worse, could be better, could be the same). Also it could be better in terms of gain, but worse in terms of sidelobes, or vice versa. Mike, your situtation of using a tribander tuned for SSB in the CW segment of band with a solid state rig is a perfect example of where using a tuner in the shack makes decent sense. 73, Mike W4EF..................................
Reply to a comment by : K9MI on 2007-03-03

A very lively and intense subject! What I do know, is that my run of the mill, 3 element tribander was assembled for the phone band. By the time I get into the lower portion of the cw band, my swr is 4:1, maybe more. With the use of an outboard tuner, it can be adjusted to where my solid state rig is now looking at a 1:1 match, not the 4:1 plus match. More then likely, the person with an antenna of the same variety is louder to the dx station then I am. Maybe not. Is my swr still 4:1? Yep. But if I'm using an antenna made for the band I'm using, but not the portion of the band, I can still have a fairly high swr, make the rig happy and work the dx. How much loss do I have with 85 ft of RG-213 at a 4:1 swr. Probably not that much. But a tuner/transmatch/coupler/impedance matching device is a necessary evil to keep my solid state rig happy. The bottom line is all I have done is make my solid state rig happy. And, I work the dx with no trouble. I'm referring to using an antenna that is made for that band. Do I still have the high swr? Sure, but I have made my rig happy and worked the dx. Is this ideal? No, but those of us that work from one end of the band to another know there are very few antenna farms the average ham can afford, or have room for, that allows that luxury. A 75m dipole fed with coax is IMO a poor choice as a multi band antenna. Feed it with 450 ohm ladder line, and you at least have your power reaching the antenna. You'll get some weird lobes, but an antenna like that is still decent (not perfect) between 75 & 20 meters. In other words, yes a resonante antenna would be great to have on all bands and all frequencies. Very few of us have that situation so you do the best you can with what you have. What is really funny to hear, or maybe sad depending on how you look at it, is to hear someone on 75 meters talking about how much better he would probably get out when he trims his dipole to get a 1:1 match instead of the 1.5:1 he has now! I don't have time to read all the responses on here, as I have other things in life that have to be done. Do the best you can with your antenna system, but don't be afraid to step out of the box either. A little! All my comments pertain to HF not VHF/UHF! 73 and enjoy ham radio! Mike, K9MI
N3OX2007-03-06
RE: Benchmarks
"The average ham cant even hear a a 3db loss (50 percent of power).........

Try noticing a 1/2 db difference on your S-Meter, doesnt make much difference does it? "

Stan, in this case I can't agree with you. For a weak , fairly QSB-free DX signal at the noise floor, 1/2, 1 or 2dB can make a substantial difference. 3dB can easily make or break the contact. If you want to get through, you care about every dB.

That said, an active DXer is going to figure out that every dB counts and doesn't need W4LGH/MLMAN_EE's twin abusive personality to help him or her figure out that they might want to put up a beam instead of a random coax-fed dipole and small MFJ tuner. ;-)

Dan
Reply to a comment by : K9IUQ on 2007-03-06

K9IUQ says With 100 watts this of course equates to 10 - 20 watts lost in the tuner. db wise the guy on the receiving end would never know if you had a tuner or not.. ................................................... A 21 percent loss = 1 db. Most S-meters calibrated at 1 S-unit= 3-6 db. K9IUQ says you couldn't even *see* a 1db loss, or hear.. The average ham cant even hear a a 3db loss (50 percent of power)......... Try noticing a 1/2 db difference on your S-Meter, doesnt make much difference does it? So anyone worrying about tuner loss is wasting his time. K9IUQ
K9IUQ2007-03-06
Benchmarks
K9IUQ says With 100 watts this of course equates to 10 - 20 watts lost in the tuner. db wise the guy on the receiving end would never know if you had a tuner or not..
...................................................

A 21 percent loss = 1 db. Most S-meters calibrated at 1 S-unit= 3-6 db.

K9IUQ says you couldn't even *see* a 1db loss, or hear..

The average ham cant even hear a a 3db loss (50 percent of power).........

Try noticing a 1/2 db difference on your S-Meter, doesnt make much difference does it?


So anyone worrying about tuner loss is wasting his time.

K9IUQ

K9IUQ2007-03-06
Benchmarks
So are we in agreement here, that using a Palstar top of the line tuner,
..................................................
We are NOT in agreement here......

Palstar, while making high quality tuners does not necessarily make low loss tuners.The ARRL reviews of Palstar tuners show that they have some of the HIGHEST loss of tuners. I was quite surprised to find this out my self.

So High Quaility does not necessarily equate to low loss.

K9IUQ
K9IUQ2007-03-06
Benchmarks
N4KC says How do they do that? How do they know what kind of components are in MY tuner? Or what the inductor (the primary source of loss) is inside MY tuner?

.....................................................
If you are an ARRL member go to their website and look up the tuner model you are interested in, in the reviews section. They have reviewed most popular tuners. As part of their testing they do loss testing in percent of power lost by the tuner. I have read all the reviews and the average loss is 10-20 percent depending on band with most tuners. With 100 watts this of course equates to 10 - 20 watts lost in the tuner. db wise the guy on the receiving end would never know if you had a tuner or not..

Stan K9IUQ
N3OX2007-03-06
RE: Benchmarks
"I never measured the Q of the coil, but I have some old "Miniductor" made with smaller diameter wire, and its Q (measured with an old Heathkit Q Meter) is *at least* 200. (That's just a guess. I know it pins the meter on its highest range.)"

W8JI's measurements suggest Miniductors are around Q=200-300 for the smaller ones.

http://w8ji.com/loading_inductors.htm

A big part of the problem really is the output caps when used on too-short antennas. My little MFJ that went all molten on me had 250pF caps. Full mesh on 80m still inserts 180 ohms of cap. reactance in series with the already highly capacitive antenna reactance (everyone puts up a too-short antenna on the low bands, right?).

Just bypassing the output capacitor entirely and using the network as a step-up L match would have almost certainly solved the problem, but this was a couple of months into my General class license in '96 or so, and I didn't know anything about impedance matching.

Those who are interested can see the effect by putting a huge capacitance in for the output capacitor in W9CF's simulator and putting in something like 10-j500 for the input impedance.

The autotuner will take the capacitor to maximum, even if you put in something like 10 million pF! Yes, 10 microfarads.

Dan
Reply to a comment by : N3OX on 2007-03-06

Oh, and don't go using my report of doing something stupid with a cheap-ass tuner against KD2BD. He's contributed excellent information to this thread, you've just muddied the waters and caused trouble. It is possible with a cheap T-network tuner to get solder-melting inductor temperatures, especially on low frequencies when you have to match a more extreme impedance because the antenna capacitor won't go below a couple hundred ohms reactance. However, at the time, I was using LADDERLINE between the tuner and the antenna and getting VERY GOOD SIGNAL REPORTS. I could work DX, I could make all sorts of contacts around the states. Clearly I was dropping some tens of watts in the tuner, but it wasn't destroying my ability to enjoy 80m operation, and I was hardly a F*$(#(%* idiot for getting on the air with that tuner on SSB or CW and having some fun and making some contacts. It didn't matter that I might have been losing 3dB in the tuner!!! Dan
Reply to a comment by : N3OX on 2007-03-06

"So are we in agreement here, that using a Palstar top of the line tuner, hooked to 7/8" andrew cable hooked to a random length dipole might not have a lot of loss, but still has loss? But the same senario using a cheap MFJ tuner hooked to RG8X might be a waste of time do to serious losses?" Yeah, like that's really what you said the first time... Gawd. Glad it took three weeks and who knows how many posts to get you to admit that it DEPENDS ON THE SITUATION. Dan
Reply to a comment by : MLMAN_EE on 2007-03-06

My point exactly! More MFJ tuners out there than any others. Most hams won't spend $600 for a nice tuner, or a buck a foot for good wire! So there you go KB2DB...your answer is YES it will get that HOT! One must remember when running ssb the duty cycle isn't that high. Hold a CW carrier thru your tuner for , oh lets say 3 minutes... then try to touch your inductor coil. Does anyone know the Q of their inductor coil in their tuner? I have never seen this specified in any ads. So are we in agreement here, that using a Palstar top of the line tuner, hooked to 7/8" andrew cable hooked to a random length dipole might not have a lot of loss, but still has loss? But the same senario using a cheap MFJ tuner hooked to RG8X might be a waste of time do to serious losses? think outside the box guys!
Reply to a comment by : N3OX on 2007-03-06

"If 100 watts were applied to the tuner for 5 solid minutes, would the coil get as hot as if we applied a 40 watt soldering iron to it for the same length of time? " If you're using a crappy Q=100 inductor and too-small caps in your tuner as you might be in a cheap MFJ tuner, yeah, it probably would. It bears mentioning that if you change the W9CF tuner parameters to something better, say 350pF caps and a Q=200 coil to get closer to what you might have in a nice high power tuner, you get a tuner loss of about half a dB. I caused a failure of a MFJ "300W" tuner by running 100W RTTY into a significant mismatch on 80m. The failure mode was to melt the styrene coil spacers AND it got hot enough to solder two turns together! I think W9CF's default tuner parameters are set to default to bottom-of-the-line MFJ low-power tuner. Dan
Reply to a comment by : MLMAN_EE on 2007-03-06

>KD2BD says, If 100 watts were applied to the tuner >for 5 solid minutes, would the coil get as hot as if >we applied a 40 watt soldering iron to it for the >same length of time? Gee, this was taken directly from an MFJ ad, >New Cabinet maintains high Q >New roomy cabinet helps maintain components’ high Q. >Vent holes help keep components cool. Wouldn't that last statement be taken to mean there is going to be heat? Next time you finish a QSO on your tuner, pop the top off and see if you can place your fingers on the inductor. You need to have it ready for quick access as it will cool, or radiate the energy that didn't make it to your antenna, pretty quickly. You can also try the same with your tank circuit in your amp too, BUT turn the POWER off first!! And also doesn't your solid-state rig has a fan on it? Mine does and heat pours out, where do you think this heat is coming from? Sure the transistors get warm, but so does the tank circuit there too. >CQ COMMON SENSE CALLING CQ COMMON SENSE Exactly!
Reply to a comment by : KD2BD on 2007-03-06

N3OX wrote: > Total loss in the W9CF tuner simulator to match the 5-j14 impedance at the shack end of the coax, 1.8dB. That still seems pretty excessive, Dan. That's 34 watts of RF lost to heat for every 100 watts applied. Wow! If 100 watts were applied to the tuner for 5 solid minutes, would the coil get as hot as if we applied a 40 watt soldering iron to it for the same length of time? And think about the inductor in your tube final's Pi Network, and ALL the inductors in the final stage of your solid state transmitter. Should we eliminate those, too? Maybe we've all been running QRP the whole time. CQ COMMON SENSE CALLING CQ COMMON SENSE... :-) 73, de John, KD2BD
Reply to a comment by : N3OX on 2007-03-05

Dipole cut for resonance at 3.53MHz, 50+j0 impedance at 3.9MHz is 75+j188, an SWR on 50 ohm line of 9.87. Total loss in 40 feet of RG-213 at this frequency and mismatch, 0.55dB. Total loss in the W9CF tuner simulator to match the 5-j14 impedance at the shack end of the coax, 1.8dB. That's 2.3dB total loss in the tuner plus the coax with a Q=100 coil in the tuner. What's 2.3dB on 75m phone? You think that matters much? It's the simplest way to stretch your 80m dipole to cover the whole band. - - - - - - There are plenty of examples that can be cooked up where the tuner at the shack end of the coax loses 3dB or 7dB or 12dB, but all it takes is one little counterexample... Dan
Reply to a comment by : MLMAN_EE on 2007-03-05

Geez...how would they know what was in your tuner? do you have some special built tuner with magical dilithum crystals? Its a basic T-Network tuner, vari. cap on input, hooked to an inductor, with a vari. cap on the output. The bigger the inductor the better, but I doubt you have a 1' diameter inductor in your box. 3db is pretty serious loss and thats before any type of line loss, and/or antenna loss. Coax adds insult to injury, open lead probably won't add to much more, but still some. QRP man! But that is ok, as you can work the world with QRP, but you sure are wasting a lot of power getting to your lossy antenna system. PUT MORE FIRE INTO THE WIRE, BYPASS THAT DAMN TUNER!
Reply to a comment by : N4KC on 2007-03-05

Man! These guys are good! Not only do they have a nice interactive website, with knobs you can crank and everything, but they also know what the loss is in MY tuner! How do they do that? How do they know what kind of components are in MY tuner? Or what the inductor (the primary source of loss) is inside MY tuner? The things they can do with cookies these days! Maybe they can also tell me the temperature in MY freezer so my spumoni won't get soft! Don N4KC www.donkeith.com/n4kc.htm
Reply to a comment by : MLMAN_EE on 2007-03-05

Here is a GREAT link that will actually show you what the losses are in your tuner, located in your shack. It is an actual T network tuner, you can spin the knobs and actually tune it. In the upper left hand corner it will show you you actual loss. I think a lot of will be surprised at what the losses REALLY are! 2 to 8DB loss in the tuner. Shows what W4LGH was talking about. Now take this loss in your tuner, then if using COAX add in that loss, then the loss of you antenna not being resonant, and what are you doing... Sounds a little ABSURD to me to use a tuner hooked to coax in your shack. Unless you are happy running QRP all the time, because thats what you are doing. Check out the link and see for yourself... http://fermi.la.asu.edu/w9cf/tuner/tuner.html Lifes to short to run QRP!
Reply to a comment by : W4EF on 2007-03-04

K9MI >> But if I'm using an antenna made for the band I'm using, but not the portion of the band, I can still have a fairly high swr, make the rig happy and work the dx. How much loss do I have with 85 ft of RG-213 at a 4:1 swr. Probably not that much. But a tuner/transmatch/coupler/impedance matching device is a necessary evil to keep my solid state rig happy. << It depends a little bit on the phase angle of the impedance at the antenna terminals, but per N6BV's TLW, the additional loss due to the 4:1 mis-match on the coax will be a whopping 0.5 dB (~10% of the incident power)!! There will be a bit more loss in the tuner (mostly in the inductor), but probably not much more than 0.1dB. So you are talking about what roughly amounts to a 0.6dB compromise in the system efficiency by tuning from the shack. Your rig if it uses a solid state final PA probably puts out at least 6dB more power when it sees a good match vs 4:1, so in terms of using the tuner in the shack versus doing nothing at all, you are likely getting a 5 or 6 dB net improvement by using the tuner. The biggest performance factor, of course, will be how the pattern of the yagi changes as you go from SSB down to CW. Without some modeling, that's anybody's guess (could be worse, could be better, could be the same). Also it could be better in terms of gain, but worse in terms of sidelobes, or vice versa. Mike, your situtation of using a tribander tuned for SSB in the CW segment of band with a solid state rig is a perfect example of where using a tuner in the shack makes decent sense. 73, Mike W4EF..................................
Reply to a comment by : K9MI on 2007-03-03

A very lively and intense subject! What I do know, is that my run of the mill, 3 element tribander was assembled for the phone band. By the time I get into the lower portion of the cw band, my swr is 4:1, maybe more. With the use of an outboard tuner, it can be adjusted to where my solid state rig is now looking at a 1:1 match, not the 4:1 plus match. More then likely, the person with an antenna of the same variety is louder to the dx station then I am. Maybe not. Is my swr still 4:1? Yep. But if I'm using an antenna made for the band I'm using, but not the portion of the band, I can still have a fairly high swr, make the rig happy and work the dx. How much loss do I have with 85 ft of RG-213 at a 4:1 swr. Probably not that much. But a tuner/transmatch/coupler/impedance matching device is a necessary evil to keep my solid state rig happy. The bottom line is all I have done is make my solid state rig happy. And, I work the dx with no trouble. I'm referring to using an antenna that is made for that band. Do I still have the high swr? Sure, but I have made my rig happy and worked the dx. Is this ideal? No, but those of us that work from one end of the band to another know there are very few antenna farms the average ham can afford, or have room for, that allows that luxury. A 75m dipole fed with coax is IMO a poor choice as a multi band antenna. Feed it with 450 ohm ladder line, and you at least have your power reaching the antenna. You'll get some weird lobes, but an antenna like that is still decent (not perfect) between 75 & 20 meters. In other words, yes a resonante antenna would be great to have on all bands and all frequencies. Very few of us have that situation so you do the best you can with what you have. What is really funny to hear, or maybe sad depending on how you look at it, is to hear someone on 75 meters talking about how much better he would probably get out when he trims his dipole to get a 1:1 match instead of the 1.5:1 he has now! I don't have time to read all the responses on here, as I have other things in life that have to be done. Do the best you can with your antenna system, but don't be afraid to step out of the box either. A little! All my comments pertain to HF not VHF/UHF! 73 and enjoy ham radio! Mike, K9MI
N3OX2007-03-06
RE: Benchmarks
Oh, and don't go using my report of doing something stupid with a cheap-ass tuner against KD2BD.

He's contributed excellent information to this thread, you've just muddied the waters and caused trouble.

It is possible with a cheap T-network tuner to get solder-melting inductor temperatures, especially on low frequencies when you have to match a more extreme impedance because the antenna capacitor won't go below a couple hundred ohms reactance. However, at the time, I was using LADDERLINE between the tuner and the antenna and getting VERY GOOD SIGNAL REPORTS. I could work DX, I could make all sorts of contacts around the states.

Clearly I was dropping some tens of watts in the tuner, but it wasn't destroying my ability to enjoy 80m operation, and I was hardly a F*$(#(%* idiot for getting on the air with that tuner on SSB or CW and having some fun and making some contacts. It didn't matter that I might have been losing 3dB in the tuner!!!

Dan
Reply to a comment by : N3OX on 2007-03-06

"So are we in agreement here, that using a Palstar top of the line tuner, hooked to 7/8" andrew cable hooked to a random length dipole might not have a lot of loss, but still has loss? But the same senario using a cheap MFJ tuner hooked to RG8X might be a waste of time do to serious losses?" Yeah, like that's really what you said the first time... Gawd. Glad it took three weeks and who knows how many posts to get you to admit that it DEPENDS ON THE SITUATION. Dan
Reply to a comment by : MLMAN_EE on 2007-03-06

My point exactly! More MFJ tuners out there than any others. Most hams won't spend $600 for a nice tuner, or a buck a foot for good wire! So there you go KB2DB...your answer is YES it will get that HOT! One must remember when running ssb the duty cycle isn't that high. Hold a CW carrier thru your tuner for , oh lets say 3 minutes... then try to touch your inductor coil. Does anyone know the Q of their inductor coil in their tuner? I have never seen this specified in any ads. So are we in agreement here, that using a Palstar top of the line tuner, hooked to 7/8" andrew cable hooked to a random length dipole might not have a lot of loss, but still has loss? But the same senario using a cheap MFJ tuner hooked to RG8X might be a waste of time do to serious losses? think outside the box guys!
Reply to a comment by : N3OX on 2007-03-06

"If 100 watts were applied to the tuner for 5 solid minutes, would the coil get as hot as if we applied a 40 watt soldering iron to it for the same length of time? " If you're using a crappy Q=100 inductor and too-small caps in your tuner as you might be in a cheap MFJ tuner, yeah, it probably would. It bears mentioning that if you change the W9CF tuner parameters to something better, say 350pF caps and a Q=200 coil to get closer to what you might have in a nice high power tuner, you get a tuner loss of about half a dB. I caused a failure of a MFJ "300W" tuner by running 100W RTTY into a significant mismatch on 80m. The failure mode was to melt the styrene coil spacers AND it got hot enough to solder two turns together! I think W9CF's default tuner parameters are set to default to bottom-of-the-line MFJ low-power tuner. Dan
Reply to a comment by : MLMAN_EE on 2007-03-06

>KD2BD says, If 100 watts were applied to the tuner >for 5 solid minutes, would the coil get as hot as if >we applied a 40 watt soldering iron to it for the >same length of time? Gee, this was taken directly from an MFJ ad, >New Cabinet maintains high Q >New roomy cabinet helps maintain components’ high Q. >Vent holes help keep components cool. Wouldn't that last statement be taken to mean there is going to be heat? Next time you finish a QSO on your tuner, pop the top off and see if you can place your fingers on the inductor. You need to have it ready for quick access as it will cool, or radiate the energy that didn't make it to your antenna, pretty quickly. You can also try the same with your tank circuit in your amp too, BUT turn the POWER off first!! And also doesn't your solid-state rig has a fan on it? Mine does and heat pours out, where do you think this heat is coming from? Sure the transistors get warm, but so does the tank circuit there too. >CQ COMMON SENSE CALLING CQ COMMON SENSE Exactly!
Reply to a comment by : KD2BD on 2007-03-06

N3OX wrote: > Total loss in the W9CF tuner simulator to match the 5-j14 impedance at the shack end of the coax, 1.8dB. That still seems pretty excessive, Dan. That's 34 watts of RF lost to heat for every 100 watts applied. Wow! If 100 watts were applied to the tuner for 5 solid minutes, would the coil get as hot as if we applied a 40 watt soldering iron to it for the same length of time? And think about the inductor in your tube final's Pi Network, and ALL the inductors in the final stage of your solid state transmitter. Should we eliminate those, too? Maybe we've all been running QRP the whole time. CQ COMMON SENSE CALLING CQ COMMON SENSE... :-) 73, de John, KD2BD
Reply to a comment by : N3OX on 2007-03-05

Dipole cut for resonance at 3.53MHz, 50+j0 impedance at 3.9MHz is 75+j188, an SWR on 50 ohm line of 9.87. Total loss in 40 feet of RG-213 at this frequency and mismatch, 0.55dB. Total loss in the W9CF tuner simulator to match the 5-j14 impedance at the shack end of the coax, 1.8dB. That's 2.3dB total loss in the tuner plus the coax with a Q=100 coil in the tuner. What's 2.3dB on 75m phone? You think that matters much? It's the simplest way to stretch your 80m dipole to cover the whole band. - - - - - - There are plenty of examples that can be cooked up where the tuner at the shack end of the coax loses 3dB or 7dB or 12dB, but all it takes is one little counterexample... Dan
Reply to a comment by : MLMAN_EE on 2007-03-05

Geez...how would they know what was in your tuner? do you have some special built tuner with magical dilithum crystals? Its a basic T-Network tuner, vari. cap on input, hooked to an inductor, with a vari. cap on the output. The bigger the inductor the better, but I doubt you have a 1' diameter inductor in your box. 3db is pretty serious loss and thats before any type of line loss, and/or antenna loss. Coax adds insult to injury, open lead probably won't add to much more, but still some. QRP man! But that is ok, as you can work the world with QRP, but you sure are wasting a lot of power getting to your lossy antenna system. PUT MORE FIRE INTO THE WIRE, BYPASS THAT DAMN TUNER!
Reply to a comment by : N4KC on 2007-03-05

Man! These guys are good! Not only do they have a nice interactive website, with knobs you can crank and everything, but they also know what the loss is in MY tuner! How do they do that? How do they know what kind of components are in MY tuner? Or what the inductor (the primary source of loss) is inside MY tuner? The things they can do with cookies these days! Maybe they can also tell me the temperature in MY freezer so my spumoni won't get soft! Don N4KC www.donkeith.com/n4kc.htm
Reply to a comment by : MLMAN_EE on 2007-03-05

Here is a GREAT link that will actually show you what the losses are in your tuner, located in your shack. It is an actual T network tuner, you can spin the knobs and actually tune it. In the upper left hand corner it will show you you actual loss. I think a lot of will be surprised at what the losses REALLY are! 2 to 8DB loss in the tuner. Shows what W4LGH was talking about. Now take this loss in your tuner, then if using COAX add in that loss, then the loss of you antenna not being resonant, and what are you doing... Sounds a little ABSURD to me to use a tuner hooked to coax in your shack. Unless you are happy running QRP all the time, because thats what you are doing. Check out the link and see for yourself... http://fermi.la.asu.edu/w9cf/tuner/tuner.html Lifes to short to run QRP!
Reply to a comment by : W4EF on 2007-03-04

K9MI >> But if I'm using an antenna made for the band I'm using, but not the portion of the band, I can still have a fairly high swr, make the rig happy and work the dx. How much loss do I have with 85 ft of RG-213 at a 4:1 swr. Probably not that much. But a tuner/transmatch/coupler/impedance matching device is a necessary evil to keep my solid state rig happy. << It depends a little bit on the phase angle of the impedance at the antenna terminals, but per N6BV's TLW, the additional loss due to the 4:1 mis-match on the coax will be a whopping 0.5 dB (~10% of the incident power)!! There will be a bit more loss in the tuner (mostly in the inductor), but probably not much more than 0.1dB. So you are talking about what roughly amounts to a 0.6dB compromise in the system efficiency by tuning from the shack. Your rig if it uses a solid state final PA probably puts out at least 6dB more power when it sees a good match vs 4:1, so in terms of using the tuner in the shack versus doing nothing at all, you are likely getting a 5 or 6 dB net improvement by using the tuner. The biggest performance factor, of course, will be how the pattern of the yagi changes as you go from SSB down to CW. Without some modeling, that's anybody's guess (could be worse, could be better, could be the same). Also it could be better in terms of gain, but worse in terms of sidelobes, or vice versa. Mike, your situtation of using a tribander tuned for SSB in the CW segment of band with a solid state rig is a perfect example of where using a tuner in the shack makes decent sense. 73, Mike W4EF..................................
Reply to a comment by : K9MI on 2007-03-03

A very lively and intense subject! What I do know, is that my run of the mill, 3 element tribander was assembled for the phone band. By the time I get into the lower portion of the cw band, my swr is 4:1, maybe more. With the use of an outboard tuner, it can be adjusted to where my solid state rig is now looking at a 1:1 match, not the 4:1 plus match. More then likely, the person with an antenna of the same variety is louder to the dx station then I am. Maybe not. Is my swr still 4:1? Yep. But if I'm using an antenna made for the band I'm using, but not the portion of the band, I can still have a fairly high swr, make the rig happy and work the dx. How much loss do I have with 85 ft of RG-213 at a 4:1 swr. Probably not that much. But a tuner/transmatch/coupler/impedance matching device is a necessary evil to keep my solid state rig happy. The bottom line is all I have done is make my solid state rig happy. And, I work the dx with no trouble. I'm referring to using an antenna that is made for that band. Do I still have the high swr? Sure, but I have made my rig happy and worked the dx. Is this ideal? No, but those of us that work from one end of the band to another know there are very few antenna farms the average ham can afford, or have room for, that allows that luxury. A 75m dipole fed with coax is IMO a poor choice as a multi band antenna. Feed it with 450 ohm ladder line, and you at least have your power reaching the antenna. You'll get some weird lobes, but an antenna like that is still decent (not perfect) between 75 & 20 meters. In other words, yes a resonante antenna would be great to have on all bands and all frequencies. Very few of us have that situation so you do the best you can with what you have. What is really funny to hear, or maybe sad depending on how you look at it, is to hear someone on 75 meters talking about how much better he would probably get out when he trims his dipole to get a 1:1 match instead of the 1.5:1 he has now! I don't have time to read all the responses on here, as I have other things in life that have to be done. Do the best you can with your antenna system, but don't be afraid to step out of the box either. A little! All my comments pertain to HF not VHF/UHF! 73 and enjoy ham radio! Mike, K9MI
KD2BD2007-03-06
RE: Benchmarks
> I think W9CF's default tuner parameters are set to default to bottom-of-the-line MFJ low-power tuner.

I agree, Dan. As such, they are a bit deceiving.

My homebrew tuner uses a hand-wound coil of #12 copper wire on about a 2" ceramic coil form, with a bit more than one wire diameter spacing between the turns. It remains stone cold at 100 watts.

I never measured the Q of the coil, but I have some old "Miniductor" made with smaller diameter wire, and its Q (measured with an old Heathkit Q Meter) is *at least* 200. (That's just a guess. I know it pins the meter on its highest range.)

The reason the big tuners add ventilation holes is because at legal-limit power levels, a mere 0.1 dB loss would equate to the 34 watt loss in the example above -- a significant amount of heat.

If the tuner's insertion loss was indeed 1.8 dB as suggested by the W9CF simulator, then at 1500 watts the loss would be in excess of 500 watts!

That amount of loss would require forced air cooling of the enclosure, not just ventilation holes!


73, de John, KD2BD
Reply to a comment by : N3OX on 2007-03-06

"If 100 watts were applied to the tuner for 5 solid minutes, would the coil get as hot as if we applied a 40 watt soldering iron to it for the same length of time? " If you're using a crappy Q=100 inductor and too-small caps in your tuner as you might be in a cheap MFJ tuner, yeah, it probably would. It bears mentioning that if you change the W9CF tuner parameters to something better, say 350pF caps and a Q=200 coil to get closer to what you might have in a nice high power tuner, you get a tuner loss of about half a dB. I caused a failure of a MFJ "300W" tuner by running 100W RTTY into a significant mismatch on 80m. The failure mode was to melt the styrene coil spacers AND it got hot enough to solder two turns together! I think W9CF's default tuner parameters are set to default to bottom-of-the-line MFJ low-power tuner. Dan
Reply to a comment by : MLMAN_EE on 2007-03-06

>KD2BD says, If 100 watts were applied to the tuner >for 5 solid minutes, would the coil get as hot as if >we applied a 40 watt soldering iron to it for the >same length of time? Gee, this was taken directly from an MFJ ad, >New Cabinet maintains high Q >New roomy cabinet helps maintain components’ high Q. >Vent holes help keep components cool. Wouldn't that last statement be taken to mean there is going to be heat? Next time you finish a QSO on your tuner, pop the top off and see if you can place your fingers on the inductor. You need to have it ready for quick access as it will cool, or radiate the energy that didn't make it to your antenna, pretty quickly. You can also try the same with your tank circuit in your amp too, BUT turn the POWER off first!! And also doesn't your solid-state rig has a fan on it? Mine does and heat pours out, where do you think this heat is coming from? Sure the transistors get warm, but so does the tank circuit there too. >CQ COMMON SENSE CALLING CQ COMMON SENSE Exactly!
Reply to a comment by : KD2BD on 2007-03-06

N3OX wrote: > Total loss in the W9CF tuner simulator to match the 5-j14 impedance at the shack end of the coax, 1.8dB. That still seems pretty excessive, Dan. That's 34 watts of RF lost to heat for every 100 watts applied. Wow! If 100 watts were applied to the tuner for 5 solid minutes, would the coil get as hot as if we applied a 40 watt soldering iron to it for the same length of time? And think about the inductor in your tube final's Pi Network, and ALL the inductors in the final stage of your solid state transmitter. Should we eliminate those, too? Maybe we've all been running QRP the whole time. CQ COMMON SENSE CALLING CQ COMMON SENSE... :-) 73, de John, KD2BD
Reply to a comment by : N3OX on 2007-03-05

Dipole cut for resonance at 3.53MHz, 50+j0 impedance at 3.9MHz is 75+j188, an SWR on 50 ohm line of 9.87. Total loss in 40 feet of RG-213 at this frequency and mismatch, 0.55dB. Total loss in the W9CF tuner simulator to match the 5-j14 impedance at the shack end of the coax, 1.8dB. That's 2.3dB total loss in the tuner plus the coax with a Q=100 coil in the tuner. What's 2.3dB on 75m phone? You think that matters much? It's the simplest way to stretch your 80m dipole to cover the whole band. - - - - - - There are plenty of examples that can be cooked up where the tuner at the shack end of the coax loses 3dB or 7dB or 12dB, but all it takes is one little counterexample... Dan
Reply to a comment by : MLMAN_EE on 2007-03-05

Geez...how would they know what was in your tuner? do you have some special built tuner with magical dilithum crystals? Its a basic T-Network tuner, vari. cap on input, hooked to an inductor, with a vari. cap on the output. The bigger the inductor the better, but I doubt you have a 1' diameter inductor in your box. 3db is pretty serious loss and thats before any type of line loss, and/or antenna loss. Coax adds insult to injury, open lead probably won't add to much more, but still some. QRP man! But that is ok, as you can work the world with QRP, but you sure are wasting a lot of power getting to your lossy antenna system. PUT MORE FIRE INTO THE WIRE, BYPASS THAT DAMN TUNER!
Reply to a comment by : N4KC on 2007-03-05

Man! These guys are good! Not only do they have a nice interactive website, with knobs you can crank and everything, but they also know what the loss is in MY tuner! How do they do that? How do they know what kind of components are in MY tuner? Or what the inductor (the primary source of loss) is inside MY tuner? The things they can do with cookies these days! Maybe they can also tell me the temperature in MY freezer so my spumoni won't get soft! Don N4KC www.donkeith.com/n4kc.htm
Reply to a comment by : MLMAN_EE on 2007-03-05

Here is a GREAT link that will actually show you what the losses are in your tuner, located in your shack. It is an actual T network tuner, you can spin the knobs and actually tune it. In the upper left hand corner it will show you you actual loss. I think a lot of will be surprised at what the losses REALLY are! 2 to 8DB loss in the tuner. Shows what W4LGH was talking about. Now take this loss in your tuner, then if using COAX add in that loss, then the loss of you antenna not being resonant, and what are you doing... Sounds a little ABSURD to me to use a tuner hooked to coax in your shack. Unless you are happy running QRP all the time, because thats what you are doing. Check out the link and see for yourself... http://fermi.la.asu.edu/w9cf/tuner/tuner.html Lifes to short to run QRP!
Reply to a comment by : W4EF on 2007-03-04

K9MI >> But if I'm using an antenna made for the band I'm using, but not the portion of the band, I can still have a fairly high swr, make the rig happy and work the dx. How much loss do I have with 85 ft of RG-213 at a 4:1 swr. Probably not that much. But a tuner/transmatch/coupler/impedance matching device is a necessary evil to keep my solid state rig happy. << It depends a little bit on the phase angle of the impedance at the antenna terminals, but per N6BV's TLW, the additional loss due to the 4:1 mis-match on the coax will be a whopping 0.5 dB (~10% of the incident power)!! There will be a bit more loss in the tuner (mostly in the inductor), but probably not much more than 0.1dB. So you are talking about what roughly amounts to a 0.6dB compromise in the system efficiency by tuning from the shack. Your rig if it uses a solid state final PA probably puts out at least 6dB more power when it sees a good match vs 4:1, so in terms of using the tuner in the shack versus doing nothing at all, you are likely getting a 5 or 6 dB net improvement by using the tuner. The biggest performance factor, of course, will be how the pattern of the yagi changes as you go from SSB down to CW. Without some modeling, that's anybody's guess (could be worse, could be better, could be the same). Also it could be better in terms of gain, but worse in terms of sidelobes, or vice versa. Mike, your situtation of using a tribander tuned for SSB in the CW segment of band with a solid state rig is a perfect example of where using a tuner in the shack makes decent sense. 73, Mike W4EF..................................
Reply to a comment by : K9MI on 2007-03-03

A very lively and intense subject! What I do know, is that my run of the mill, 3 element tribander was assembled for the phone band. By the time I get into the lower portion of the cw band, my swr is 4:1, maybe more. With the use of an outboard tuner, it can be adjusted to where my solid state rig is now looking at a 1:1 match, not the 4:1 plus match. More then likely, the person with an antenna of the same variety is louder to the dx station then I am. Maybe not. Is my swr still 4:1? Yep. But if I'm using an antenna made for the band I'm using, but not the portion of the band, I can still have a fairly high swr, make the rig happy and work the dx. How much loss do I have with 85 ft of RG-213 at a 4:1 swr. Probably not that much. But a tuner/transmatch/coupler/impedance matching device is a necessary evil to keep my solid state rig happy. The bottom line is all I have done is make my solid state rig happy. And, I work the dx with no trouble. I'm referring to using an antenna that is made for that band. Do I still have the high swr? Sure, but I have made my rig happy and worked the dx. Is this ideal? No, but those of us that work from one end of the band to another know there are very few antenna farms the average ham can afford, or have room for, that allows that luxury. A 75m dipole fed with coax is IMO a poor choice as a multi band antenna. Feed it with 450 ohm ladder line, and you at least have your power reaching the antenna. You'll get some weird lobes, but an antenna like that is still decent (not perfect) between 75 & 20 meters. In other words, yes a resonante antenna would be great to have on all bands and all frequencies. Very few of us have that situation so you do the best you can with what you have. What is really funny to hear, or maybe sad depending on how you look at it, is to hear someone on 75 meters talking about how much better he would probably get out when he trims his dipole to get a 1:1 match instead of the 1.5:1 he has now! I don't have time to read all the responses on here, as I have other things in life that have to be done. Do the best you can with your antenna system, but don't be afraid to step out of the box either. A little! All my comments pertain to HF not VHF/UHF! 73 and enjoy ham radio! Mike, K9MI
N3OX2007-03-06
RE: Benchmarks
"So are we in agreement here, that using a Palstar top of the line tuner, hooked to 7/8" andrew cable hooked to a random length dipole might not have a lot of loss, but still has loss? But the same senario using a cheap MFJ tuner hooked to RG8X might be a waste of time do to serious losses?"

Yeah, like that's really what you said the first time...

Gawd. Glad it took three weeks and who knows how many posts to get you to admit that it DEPENDS ON THE SITUATION.

Dan
Reply to a comment by : MLMAN_EE on 2007-03-06

My point exactly! More MFJ tuners out there than any others. Most hams won't spend $600 for a nice tuner, or a buck a foot for good wire! So there you go KB2DB...your answer is YES it will get that HOT! One must remember when running ssb the duty cycle isn't that high. Hold a CW carrier thru your tuner for , oh lets say 3 minutes... then try to touch your inductor coil. Does anyone know the Q of their inductor coil in their tuner? I have never seen this specified in any ads. So are we in agreement here, that using a Palstar top of the line tuner, hooked to 7/8" andrew cable hooked to a random length dipole might not have a lot of loss, but still has loss? But the same senario using a cheap MFJ tuner hooked to RG8X might be a waste of time do to serious losses? think outside the box guys!
Reply to a comment by : N3OX on 2007-03-06

"If 100 watts were applied to the tuner for 5 solid minutes, would the coil get as hot as if we applied a 40 watt soldering iron to it for the same length of time? " If you're using a crappy Q=100 inductor and too-small caps in your tuner as you might be in a cheap MFJ tuner, yeah, it probably would. It bears mentioning that if you change the W9CF tuner parameters to something better, say 350pF caps and a Q=200 coil to get closer to what you might have in a nice high power tuner, you get a tuner loss of about half a dB. I caused a failure of a MFJ "300W" tuner by running 100W RTTY into a significant mismatch on 80m. The failure mode was to melt the styrene coil spacers AND it got hot enough to solder two turns together! I think W9CF's default tuner parameters are set to default to bottom-of-the-line MFJ low-power tuner. Dan
Reply to a comment by : MLMAN_EE on 2007-03-06

>KD2BD says, If 100 watts were applied to the tuner >for 5 solid minutes, would the coil get as hot as if >we applied a 40 watt soldering iron to it for the >same length of time? Gee, this was taken directly from an MFJ ad, >New Cabinet maintains high Q >New roomy cabinet helps maintain components’ high Q. >Vent holes help keep components cool. Wouldn't that last statement be taken to mean there is going to be heat? Next time you finish a QSO on your tuner, pop the top off and see if you can place your fingers on the inductor. You need to have it ready for quick access as it will cool, or radiate the energy that didn't make it to your antenna, pretty quickly. You can also try the same with your tank circuit in your amp too, BUT turn the POWER off first!! And also doesn't your solid-state rig has a fan on it? Mine does and heat pours out, where do you think this heat is coming from? Sure the transistors get warm, but so does the tank circuit there too. >CQ COMMON SENSE CALLING CQ COMMON SENSE Exactly!
Reply to a comment by : KD2BD on 2007-03-06

N3OX wrote: > Total loss in the W9CF tuner simulator to match the 5-j14 impedance at the shack end of the coax, 1.8dB. That still seems pretty excessive, Dan. That's 34 watts of RF lost to heat for every 100 watts applied. Wow! If 100 watts were applied to the tuner for 5 solid minutes, would the coil get as hot as if we applied a 40 watt soldering iron to it for the same length of time? And think about the inductor in your tube final's Pi Network, and ALL the inductors in the final stage of your solid state transmitter. Should we eliminate those, too? Maybe we've all been running QRP the whole time. CQ COMMON SENSE CALLING CQ COMMON SENSE... :-) 73, de John, KD2BD
Reply to a comment by : N3OX on 2007-03-05

Dipole cut for resonance at 3.53MHz, 50+j0 impedance at 3.9MHz is 75+j188, an SWR on 50 ohm line of 9.87. Total loss in 40 feet of RG-213 at this frequency and mismatch, 0.55dB. Total loss in the W9CF tuner simulator to match the 5-j14 impedance at the shack end of the coax, 1.8dB. That's 2.3dB total loss in the tuner plus the coax with a Q=100 coil in the tuner. What's 2.3dB on 75m phone? You think that matters much? It's the simplest way to stretch your 80m dipole to cover the whole band. - - - - - - There are plenty of examples that can be cooked up where the tuner at the shack end of the coax loses 3dB or 7dB or 12dB, but all it takes is one little counterexample... Dan
Reply to a comment by : MLMAN_EE on 2007-03-05

Geez...how would they know what was in your tuner? do you have some special built tuner with magical dilithum crystals? Its a basic T-Network tuner, vari. cap on input, hooked to an inductor, with a vari. cap on the output. The bigger the inductor the better, but I doubt you have a 1' diameter inductor in your box. 3db is pretty serious loss and thats before any type of line loss, and/or antenna loss. Coax adds insult to injury, open lead probably won't add to much more, but still some. QRP man! But that is ok, as you can work the world with QRP, but you sure are wasting a lot of power getting to your lossy antenna system. PUT MORE FIRE INTO THE WIRE, BYPASS THAT DAMN TUNER!
Reply to a comment by : N4KC on 2007-03-05

Man! These guys are good! Not only do they have a nice interactive website, with knobs you can crank and everything, but they also know what the loss is in MY tuner! How do they do that? How do they know what kind of components are in MY tuner? Or what the inductor (the primary source of loss) is inside MY tuner? The things they can do with cookies these days! Maybe they can also tell me the temperature in MY freezer so my spumoni won't get soft! Don N4KC www.donkeith.com/n4kc.htm
Reply to a comment by : MLMAN_EE on 2007-03-05

Here is a GREAT link that will actually show you what the losses are in your tuner, located in your shack. It is an actual T network tuner, you can spin the knobs and actually tune it. In the upper left hand corner it will show you you actual loss. I think a lot of will be surprised at what the losses REALLY are! 2 to 8DB loss in the tuner. Shows what W4LGH was talking about. Now take this loss in your tuner, then if using COAX add in that loss, then the loss of you antenna not being resonant, and what are you doing... Sounds a little ABSURD to me to use a tuner hooked to coax in your shack. Unless you are happy running QRP all the time, because thats what you are doing. Check out the link and see for yourself... http://fermi.la.asu.edu/w9cf/tuner/tuner.html Lifes to short to run QRP!
Reply to a comment by : W4EF on 2007-03-04

K9MI >> But if I'm using an antenna made for the band I'm using, but not the portion of the band, I can still have a fairly high swr, make the rig happy and work the dx. How much loss do I have with 85 ft of RG-213 at a 4:1 swr. Probably not that much. But a tuner/transmatch/coupler/impedance matching device is a necessary evil to keep my solid state rig happy. << It depends a little bit on the phase angle of the impedance at the antenna terminals, but per N6BV's TLW, the additional loss due to the 4:1 mis-match on the coax will be a whopping 0.5 dB (~10% of the incident power)!! There will be a bit more loss in the tuner (mostly in the inductor), but probably not much more than 0.1dB. So you are talking about what roughly amounts to a 0.6dB compromise in the system efficiency by tuning from the shack. Your rig if it uses a solid state final PA probably puts out at least 6dB more power when it sees a good match vs 4:1, so in terms of using the tuner in the shack versus doing nothing at all, you are likely getting a 5 or 6 dB net improvement by using the tuner. The biggest performance factor, of course, will be how the pattern of the yagi changes as you go from SSB down to CW. Without some modeling, that's anybody's guess (could be worse, could be better, could be the same). Also it could be better in terms of gain, but worse in terms of sidelobes, or vice versa. Mike, your situtation of using a tribander tuned for SSB in the CW segment of band with a solid state rig is a perfect example of where using a tuner in the shack makes decent sense. 73, Mike W4EF..................................
Reply to a comment by : K9MI on 2007-03-03

A very lively and intense subject! What I do know, is that my run of the mill, 3 element tribander was assembled for the phone band. By the time I get into the lower portion of the cw band, my swr is 4:1, maybe more. With the use of an outboard tuner, it can be adjusted to where my solid state rig is now looking at a 1:1 match, not the 4:1 plus match. More then likely, the person with an antenna of the same variety is louder to the dx station then I am. Maybe not. Is my swr still 4:1? Yep. But if I'm using an antenna made for the band I'm using, but not the portion of the band, I can still have a fairly high swr, make the rig happy and work the dx. How much loss do I have with 85 ft of RG-213 at a 4:1 swr. Probably not that much. But a tuner/transmatch/coupler/impedance matching device is a necessary evil to keep my solid state rig happy. The bottom line is all I have done is make my solid state rig happy. And, I work the dx with no trouble. I'm referring to using an antenna that is made for that band. Do I still have the high swr? Sure, but I have made my rig happy and worked the dx. Is this ideal? No, but those of us that work from one end of the band to another know there are very few antenna farms the average ham can afford, or have room for, that allows that luxury. A 75m dipole fed with coax is IMO a poor choice as a multi band antenna. Feed it with 450 ohm ladder line, and you at least have your power reaching the antenna. You'll get some weird lobes, but an antenna like that is still decent (not perfect) between 75 & 20 meters. In other words, yes a resonante antenna would be great to have on all bands and all frequencies. Very few of us have that situation so you do the best you can with what you have. What is really funny to hear, or maybe sad depending on how you look at it, is to hear someone on 75 meters talking about how much better he would probably get out when he trims his dipole to get a 1:1 match instead of the 1.5:1 he has now! I don't have time to read all the responses on here, as I have other things in life that have to be done. Do the best you can with your antenna system, but don't be afraid to step out of the box either. A little! All my comments pertain to HF not VHF/UHF! 73 and enjoy ham radio! Mike, K9MI
MLMAN_EE2007-03-06
RE: Benchmarks
My point exactly! More MFJ tuners out there than any others. Most hams won't spend $600 for a nice tuner, or a buck a foot for good wire!

So there you go KB2DB...your answer is YES it will get that HOT! One must remember when running ssb the duty cycle isn't that high. Hold a CW carrier thru your tuner for , oh lets say 3 minutes... then try to touch your inductor coil.

Does anyone know the Q of their inductor coil in their tuner? I have never seen this specified in any ads.

So are we in agreement here, that using a Palstar top of the line tuner, hooked to 7/8" andrew cable hooked to a random length dipole might not have a lot of loss, but still has loss? But the same senario using a cheap MFJ tuner hooked to RG8X might be a waste of time do to serious losses?

think outside the box guys!



Reply to a comment by : N3OX on 2007-03-06

"If 100 watts were applied to the tuner for 5 solid minutes, would the coil get as hot as if we applied a 40 watt soldering iron to it for the same length of time? " If you're using a crappy Q=100 inductor and too-small caps in your tuner as you might be in a cheap MFJ tuner, yeah, it probably would. It bears mentioning that if you change the W9CF tuner parameters to something better, say 350pF caps and a Q=200 coil to get closer to what you might have in a nice high power tuner, you get a tuner loss of about half a dB. I caused a failure of a MFJ "300W" tuner by running 100W RTTY into a significant mismatch on 80m. The failure mode was to melt the styrene coil spacers AND it got hot enough to solder two turns together! I think W9CF's default tuner parameters are set to default to bottom-of-the-line MFJ low-power tuner. Dan
Reply to a comment by : MLMAN_EE on 2007-03-06

>KD2BD says, If 100 watts were applied to the tuner >for 5 solid minutes, would the coil get as hot as if >we applied a 40 watt soldering iron to it for the >same length of time? Gee, this was taken directly from an MFJ ad, >New Cabinet maintains high Q >New roomy cabinet helps maintain components’ high Q. >Vent holes help keep components cool. Wouldn't that last statement be taken to mean there is going to be heat? Next time you finish a QSO on your tuner, pop the top off and see if you can place your fingers on the inductor. You need to have it ready for quick access as it will cool, or radiate the energy that didn't make it to your antenna, pretty quickly. You can also try the same with your tank circuit in your amp too, BUT turn the POWER off first!! And also doesn't your solid-state rig has a fan on it? Mine does and heat pours out, where do you think this heat is coming from? Sure the transistors get warm, but so does the tank circuit there too. >CQ COMMON SENSE CALLING CQ COMMON SENSE Exactly!
Reply to a comment by : KD2BD on 2007-03-06

N3OX wrote: > Total loss in the W9CF tuner simulator to match the 5-j14 impedance at the shack end of the coax, 1.8dB. That still seems pretty excessive, Dan. That's 34 watts of RF lost to heat for every 100 watts applied. Wow! If 100 watts were applied to the tuner for 5 solid minutes, would the coil get as hot as if we applied a 40 watt soldering iron to it for the same length of time? And think about the inductor in your tube final's Pi Network, and ALL the inductors in the final stage of your solid state transmitter. Should we eliminate those, too? Maybe we've all been running QRP the whole time. CQ COMMON SENSE CALLING CQ COMMON SENSE... :-) 73, de John, KD2BD
Reply to a comment by : N3OX on 2007-03-05

Dipole cut for resonance at 3.53MHz, 50+j0 impedance at 3.9MHz is 75+j188, an SWR on 50 ohm line of 9.87. Total loss in 40 feet of RG-213 at this frequency and mismatch, 0.55dB. Total loss in the W9CF tuner simulator to match the 5-j14 impedance at the shack end of the coax, 1.8dB. That's 2.3dB total loss in the tuner plus the coax with a Q=100 coil in the tuner. What's 2.3dB on 75m phone? You think that matters much? It's the simplest way to stretch your 80m dipole to cover the whole band. - - - - - - There are plenty of examples that can be cooked up where the tuner at the shack end of the coax loses 3dB or 7dB or 12dB, but all it takes is one little counterexample... Dan
Reply to a comment by : MLMAN_EE on 2007-03-05

Geez...how would they know what was in your tuner? do you have some special built tuner with magical dilithum crystals? Its a basic T-Network tuner, vari. cap on input, hooked to an inductor, with a vari. cap on the output. The bigger the inductor the better, but I doubt you have a 1' diameter inductor in your box. 3db is pretty serious loss and thats before any type of line loss, and/or antenna loss. Coax adds insult to injury, open lead probably won't add to much more, but still some. QRP man! But that is ok, as you can work the world with QRP, but you sure are wasting a lot of power getting to your lossy antenna system. PUT MORE FIRE INTO THE WIRE, BYPASS THAT DAMN TUNER!
Reply to a comment by : N4KC on 2007-03-05

Man! These guys are good! Not only do they have a nice interactive website, with knobs you can crank and everything, but they also know what the loss is in MY tuner! How do they do that? How do they know what kind of components are in MY tuner? Or what the inductor (the primary source of loss) is inside MY tuner? The things they can do with cookies these days! Maybe they can also tell me the temperature in MY freezer so my spumoni won't get soft! Don N4KC www.donkeith.com/n4kc.htm
Reply to a comment by : MLMAN_EE on 2007-03-05

Here is a GREAT link that will actually show you what the losses are in your tuner, located in your shack. It is an actual T network tuner, you can spin the knobs and actually tune it. In the upper left hand corner it will show you you actual loss. I think a lot of will be surprised at what the losses REALLY are! 2 to 8DB loss in the tuner. Shows what W4LGH was talking about. Now take this loss in your tuner, then if using COAX add in that loss, then the loss of you antenna not being resonant, and what are you doing... Sounds a little ABSURD to me to use a tuner hooked to coax in your shack. Unless you are happy running QRP all the time, because thats what you are doing. Check out the link and see for yourself... http://fermi.la.asu.edu/w9cf/tuner/tuner.html Lifes to short to run QRP!
Reply to a comment by : W4EF on 2007-03-04

K9MI >> But if I'm using an antenna made for the band I'm using, but not the portion of the band, I can still have a fairly high swr, make the rig happy and work the dx. How much loss do I have with 85 ft of RG-213 at a 4:1 swr. Probably not that much. But a tuner/transmatch/coupler/impedance matching device is a necessary evil to keep my solid state rig happy. << It depends a little bit on the phase angle of the impedance at the antenna terminals, but per N6BV's TLW, the additional loss due to the 4:1 mis-match on the coax will be a whopping 0.5 dB (~10% of the incident power)!! There will be a bit more loss in the tuner (mostly in the inductor), but probably not much more than 0.1dB. So you are talking about what roughly amounts to a 0.6dB compromise in the system efficiency by tuning from the shack. Your rig if it uses a solid state final PA probably puts out at least 6dB more power when it sees a good match vs 4:1, so in terms of using the tuner in the shack versus doing nothing at all, you are likely getting a 5 or 6 dB net improvement by using the tuner. The biggest performance factor, of course, will be how the pattern of the yagi changes as you go from SSB down to CW. Without some modeling, that's anybody's guess (could be worse, could be better, could be the same). Also it could be better in terms of gain, but worse in terms of sidelobes, or vice versa. Mike, your situtation of using a tribander tuned for SSB in the CW segment of band with a solid state rig is a perfect example of where using a tuner in the shack makes decent sense. 73, Mike W4EF..................................
Reply to a comment by : K9MI on 2007-03-03

A very lively and intense subject! What I do know, is that my run of the mill, 3 element tribander was assembled for the phone band. By the time I get into the lower portion of the cw band, my swr is 4:1, maybe more. With the use of an outboard tuner, it can be adjusted to where my solid state rig is now looking at a 1:1 match, not the 4:1 plus match. More then likely, the person with an antenna of the same variety is louder to the dx station then I am. Maybe not. Is my swr still 4:1? Yep. But if I'm using an antenna made for the band I'm using, but not the portion of the band, I can still have a fairly high swr, make the rig happy and work the dx. How much loss do I have with 85 ft of RG-213 at a 4:1 swr. Probably not that much. But a tuner/transmatch/coupler/impedance matching device is a necessary evil to keep my solid state rig happy. The bottom line is all I have done is make my solid state rig happy. And, I work the dx with no trouble. I'm referring to using an antenna that is made for that band. Do I still have the high swr? Sure, but I have made my rig happy and worked the dx. Is this ideal? No, but those of us that work from one end of the band to another know there are very few antenna farms the average ham can afford, or have room for, that allows that luxury. A 75m dipole fed with coax is IMO a poor choice as a multi band antenna. Feed it with 450 ohm ladder line, and you at least have your power reaching the antenna. You'll get some weird lobes, but an antenna like that is still decent (not perfect) between 75 & 20 meters. In other words, yes a resonante antenna would be great to have on all bands and all frequencies. Very few of us have that situation so you do the best you can with what you have. What is really funny to hear, or maybe sad depending on how you look at it, is to hear someone on 75 meters talking about how much better he would probably get out when he trims his dipole to get a 1:1 match instead of the 1.5:1 he has now! I don't have time to read all the responses on here, as I have other things in life that have to be done. Do the best you can with your antenna system, but don't be afraid to step out of the box either. A little! All my comments pertain to HF not VHF/UHF! 73 and enjoy ham radio! Mike, K9MI
N3OX2007-03-06
RE: Benchmarks
"If 100 watts were applied to the tuner for 5 solid minutes, would the coil get as hot as if we applied a 40 watt soldering iron to it for the same length of time? "

If you're using a crappy Q=100 inductor and too-small caps in your tuner as you might be in a cheap MFJ tuner, yeah, it probably would. It bears mentioning that if you change the W9CF tuner parameters to something better, say 350pF caps and a Q=200 coil to get closer to what you might have in a nice high power tuner, you get a tuner loss of about half a dB.

I caused a failure of a MFJ "300W" tuner by running 100W RTTY into a significant mismatch on 80m. The failure mode was to melt the styrene coil spacers AND it got hot enough to solder two turns together!

I think W9CF's default tuner parameters are set to default to bottom-of-the-line MFJ low-power tuner.

Dan
Reply to a comment by : MLMAN_EE on 2007-03-06

>KD2BD says, If 100 watts were applied to the tuner >for 5 solid minutes, would the coil get as hot as if >we applied a 40 watt soldering iron to it for the >same length of time? Gee, this was taken directly from an MFJ ad, >New Cabinet maintains high Q >New roomy cabinet helps maintain components’ high Q. >Vent holes help keep components cool. Wouldn't that last statement be taken to mean there is going to be heat? Next time you finish a QSO on your tuner, pop the top off and see if you can place your fingers on the inductor. You need to have it ready for quick access as it will cool, or radiate the energy that didn't make it to your antenna, pretty quickly. You can also try the same with your tank circuit in your amp too, BUT turn the POWER off first!! And also doesn't your solid-state rig has a fan on it? Mine does and heat pours out, where do you think this heat is coming from? Sure the transistors get warm, but so does the tank circuit there too. >CQ COMMON SENSE CALLING CQ COMMON SENSE Exactly!
Reply to a comment by : KD2BD on 2007-03-06

N3OX wrote: > Total loss in the W9CF tuner simulator to match the 5-j14 impedance at the shack end of the coax, 1.8dB. That still seems pretty excessive, Dan. That's 34 watts of RF lost to heat for every 100 watts applied. Wow! If 100 watts were applied to the tuner for 5 solid minutes, would the coil get as hot as if we applied a 40 watt soldering iron to it for the same length of time? And think about the inductor in your tube final's Pi Network, and ALL the inductors in the final stage of your solid state transmitter. Should we eliminate those, too? Maybe we've all been running QRP the whole time. CQ COMMON SENSE CALLING CQ COMMON SENSE... :-) 73, de John, KD2BD
Reply to a comment by : N3OX on 2007-03-05

Dipole cut for resonance at 3.53MHz, 50+j0 impedance at 3.9MHz is 75+j188, an SWR on 50 ohm line of 9.87. Total loss in 40 feet of RG-213 at this frequency and mismatch, 0.55dB. Total loss in the W9CF tuner simulator to match the 5-j14 impedance at the shack end of the coax, 1.8dB. That's 2.3dB total loss in the tuner plus the coax with a Q=100 coil in the tuner. What's 2.3dB on 75m phone? You think that matters much? It's the simplest way to stretch your 80m dipole to cover the whole band. - - - - - - There are plenty of examples that can be cooked up where the tuner at the shack end of the coax loses 3dB or 7dB or 12dB, but all it takes is one little counterexample... Dan
Reply to a comment by : MLMAN_EE on 2007-03-05

Geez...how would they know what was in your tuner? do you have some special built tuner with magical dilithum crystals? Its a basic T-Network tuner, vari. cap on input, hooked to an inductor, with a vari. cap on the output. The bigger the inductor the better, but I doubt you have a 1' diameter inductor in your box. 3db is pretty serious loss and thats before any type of line loss, and/or antenna loss. Coax adds insult to injury, open lead probably won't add to much more, but still some. QRP man! But that is ok, as you can work the world with QRP, but you sure are wasting a lot of power getting to your lossy antenna system. PUT MORE FIRE INTO THE WIRE, BYPASS THAT DAMN TUNER!
Reply to a comment by : N4KC on 2007-03-05

Man! These guys are good! Not only do they have a nice interactive website, with knobs you can crank and everything, but they also know what the loss is in MY tuner! How do they do that? How do they know what kind of components are in MY tuner? Or what the inductor (the primary source of loss) is inside MY tuner? The things they can do with cookies these days! Maybe they can also tell me the temperature in MY freezer so my spumoni won't get soft! Don N4KC www.donkeith.com/n4kc.htm
Reply to a comment by : MLMAN_EE on 2007-03-05

Here is a GREAT link that will actually show you what the losses are in your tuner, located in your shack. It is an actual T network tuner, you can spin the knobs and actually tune it. In the upper left hand corner it will show you you actual loss. I think a lot of will be surprised at what the losses REALLY are! 2 to 8DB loss in the tuner. Shows what W4LGH was talking about. Now take this loss in your tuner, then if using COAX add in that loss, then the loss of you antenna not being resonant, and what are you doing... Sounds a little ABSURD to me to use a tuner hooked to coax in your shack. Unless you are happy running QRP all the time, because thats what you are doing. Check out the link and see for yourself... http://fermi.la.asu.edu/w9cf/tuner/tuner.html Lifes to short to run QRP!
Reply to a comment by : W4EF on 2007-03-04

K9MI >> But if I'm using an antenna made for the band I'm using, but not the portion of the band, I can still have a fairly high swr, make the rig happy and work the dx. How much loss do I have with 85 ft of RG-213 at a 4:1 swr. Probably not that much. But a tuner/transmatch/coupler/impedance matching device is a necessary evil to keep my solid state rig happy. << It depends a little bit on the phase angle of the impedance at the antenna terminals, but per N6BV's TLW, the additional loss due to the 4:1 mis-match on the coax will be a whopping 0.5 dB (~10% of the incident power)!! There will be a bit more loss in the tuner (mostly in the inductor), but probably not much more than 0.1dB. So you are talking about what roughly amounts to a 0.6dB compromise in the system efficiency by tuning from the shack. Your rig if it uses a solid state final PA probably puts out at least 6dB more power when it sees a good match vs 4:1, so in terms of using the tuner in the shack versus doing nothing at all, you are likely getting a 5 or 6 dB net improvement by using the tuner. The biggest performance factor, of course, will be how the pattern of the yagi changes as you go from SSB down to CW. Without some modeling, that's anybody's guess (could be worse, could be better, could be the same). Also it could be better in terms of gain, but worse in terms of sidelobes, or vice versa. Mike, your situtation of using a tribander tuned for SSB in the CW segment of band with a solid state rig is a perfect example of where using a tuner in the shack makes decent sense. 73, Mike W4EF..................................
Reply to a comment by : K9MI on 2007-03-03

A very lively and intense subject! What I do know, is that my run of the mill, 3 element tribander was assembled for the phone band. By the time I get into the lower portion of the cw band, my swr is 4:1, maybe more. With the use of an outboard tuner, it can be adjusted to where my solid state rig is now looking at a 1:1 match, not the 4:1 plus match. More then likely, the person with an antenna of the same variety is louder to the dx station then I am. Maybe not. Is my swr still 4:1? Yep. But if I'm using an antenna made for the band I'm using, but not the portion of the band, I can still have a fairly high swr, make the rig happy and work the dx. How much loss do I have with 85 ft of RG-213 at a 4:1 swr. Probably not that much. But a tuner/transmatch/coupler/impedance matching device is a necessary evil to keep my solid state rig happy. The bottom line is all I have done is make my solid state rig happy. And, I work the dx with no trouble. I'm referring to using an antenna that is made for that band. Do I still have the high swr? Sure, but I have made my rig happy and worked the dx. Is this ideal? No, but those of us that work from one end of the band to another know there are very few antenna farms the average ham can afford, or have room for, that allows that luxury. A 75m dipole fed with coax is IMO a poor choice as a multi band antenna. Feed it with 450 ohm ladder line, and you at least have your power reaching the antenna. You'll get some weird lobes, but an antenna like that is still decent (not perfect) between 75 & 20 meters. In other words, yes a resonante antenna would be great to have on all bands and all frequencies. Very few of us have that situation so you do the best you can with what you have. What is really funny to hear, or maybe sad depending on how you look at it, is to hear someone on 75 meters talking about how much better he would probably get out when he trims his dipole to get a 1:1 match instead of the 1.5:1 he has now! I don't have time to read all the responses on here, as I have other things in life that have to be done. Do the best you can with your antenna system, but don't be afraid to step out of the box either. A little! All my comments pertain to HF not VHF/UHF! 73 and enjoy ham radio! Mike, K9MI
MLMAN_EE2007-03-06
RE: Benchmarks
>KD2BD says, If 100 watts were applied to the tuner >for 5 solid minutes, would the coil get as hot as if >we applied a 40 watt soldering iron to it for the >same length of time?

Gee, this was taken directly from an MFJ ad,
>New Cabinet maintains high Q
>New roomy cabinet helps maintain components’ high Q. >Vent holes help keep components cool.
Wouldn't that last statement be taken to mean there is going to be heat? Next time you finish a QSO on your tuner, pop the top off and see if you can place your fingers on the inductor. You need to have it ready for quick access as it will cool, or radiate the energy that didn't make it to your antenna, pretty quickly. You can also try the same with your tank circuit in your amp too, BUT turn the POWER off first!! And also doesn't your solid-state rig has a fan on it? Mine does and heat pours out, where do you think this heat is coming from? Sure the transistors get warm, but so does the tank circuit there too.

>CQ COMMON SENSE CALLING CQ COMMON SENSE
Exactly!

Reply to a comment by : KD2BD on 2007-03-06

N3OX wrote: > Total loss in the W9CF tuner simulator to match the 5-j14 impedance at the shack end of the coax, 1.8dB. That still seems pretty excessive, Dan. That's 34 watts of RF lost to heat for every 100 watts applied. Wow! If 100 watts were applied to the tuner for 5 solid minutes, would the coil get as hot as if we applied a 40 watt soldering iron to it for the same length of time? And think about the inductor in your tube final's Pi Network, and ALL the inductors in the final stage of your solid state transmitter. Should we eliminate those, too? Maybe we've all been running QRP the whole time. CQ COMMON SENSE CALLING CQ COMMON SENSE... :-) 73, de John, KD2BD
Reply to a comment by : N3OX on 2007-03-05

Dipole cut for resonance at 3.53MHz, 50+j0 impedance at 3.9MHz is 75+j188, an SWR on 50 ohm line of 9.87. Total loss in 40 feet of RG-213 at this frequency and mismatch, 0.55dB. Total loss in the W9CF tuner simulator to match the 5-j14 impedance at the shack end of the coax, 1.8dB. That's 2.3dB total loss in the tuner plus the coax with a Q=100 coil in the tuner. What's 2.3dB on 75m phone? You think that matters much? It's the simplest way to stretch your 80m dipole to cover the whole band. - - - - - - There are plenty of examples that can be cooked up where the tuner at the shack end of the coax loses 3dB or 7dB or 12dB, but all it takes is one little counterexample... Dan
Reply to a comment by : MLMAN_EE on 2007-03-05

Geez...how would they know what was in your tuner? do you have some special built tuner with magical dilithum crystals? Its a basic T-Network tuner, vari. cap on input, hooked to an inductor, with a vari. cap on the output. The bigger the inductor the better, but I doubt you have a 1' diameter inductor in your box. 3db is pretty serious loss and thats before any type of line loss, and/or antenna loss. Coax adds insult to injury, open lead probably won't add to much more, but still some. QRP man! But that is ok, as you can work the world with QRP, but you sure are wasting a lot of power getting to your lossy antenna system. PUT MORE FIRE INTO THE WIRE, BYPASS THAT DAMN TUNER!
Reply to a comment by : N4KC on 2007-03-05

Man! These guys are good! Not only do they have a nice interactive website, with knobs you can crank and everything, but they also know what the loss is in MY tuner! How do they do that? How do they know what kind of components are in MY tuner? Or what the inductor (the primary source of loss) is inside MY tuner? The things they can do with cookies these days! Maybe they can also tell me the temperature in MY freezer so my spumoni won't get soft! Don N4KC www.donkeith.com/n4kc.htm
Reply to a comment by : MLMAN_EE on 2007-03-05

Here is a GREAT link that will actually show you what the losses are in your tuner, located in your shack. It is an actual T network tuner, you can spin the knobs and actually tune it. In the upper left hand corner it will show you you actual loss. I think a lot of will be surprised at what the losses REALLY are! 2 to 8DB loss in the tuner. Shows what W4LGH was talking about. Now take this loss in your tuner, then if using COAX add in that loss, then the loss of you antenna not being resonant, and what are you doing... Sounds a little ABSURD to me to use a tuner hooked to coax in your shack. Unless you are happy running QRP all the time, because thats what you are doing. Check out the link and see for yourself... http://fermi.la.asu.edu/w9cf/tuner/tuner.html Lifes to short to run QRP!
Reply to a comment by : W4EF on 2007-03-04

K9MI >> But if I'm using an antenna made for the band I'm using, but not the portion of the band, I can still have a fairly high swr, make the rig happy and work the dx. How much loss do I have with 85 ft of RG-213 at a 4:1 swr. Probably not that much. But a tuner/transmatch/coupler/impedance matching device is a necessary evil to keep my solid state rig happy. << It depends a little bit on the phase angle of the impedance at the antenna terminals, but per N6BV's TLW, the additional loss due to the 4:1 mis-match on the coax will be a whopping 0.5 dB (~10% of the incident power)!! There will be a bit more loss in the tuner (mostly in the inductor), but probably not much more than 0.1dB. So you are talking about what roughly amounts to a 0.6dB compromise in the system efficiency by tuning from the shack. Your rig if it uses a solid state final PA probably puts out at least 6dB more power when it sees a good match vs 4:1, so in terms of using the tuner in the shack versus doing nothing at all, you are likely getting a 5 or 6 dB net improvement by using the tuner. The biggest performance factor, of course, will be how the pattern of the yagi changes as you go from SSB down to CW. Without some modeling, that's anybody's guess (could be worse, could be better, could be the same). Also it could be better in terms of gain, but worse in terms of sidelobes, or vice versa. Mike, your situtation of using a tribander tuned for SSB in the CW segment of band with a solid state rig is a perfect example of where using a tuner in the shack makes decent sense. 73, Mike W4EF..................................
Reply to a comment by : K9MI on 2007-03-03

A very lively and intense subject! What I do know, is that my run of the mill, 3 element tribander was assembled for the phone band. By the time I get into the lower portion of the cw band, my swr is 4:1, maybe more. With the use of an outboard tuner, it can be adjusted to where my solid state rig is now looking at a 1:1 match, not the 4:1 plus match. More then likely, the person with an antenna of the same variety is louder to the dx station then I am. Maybe not. Is my swr still 4:1? Yep. But if I'm using an antenna made for the band I'm using, but not the portion of the band, I can still have a fairly high swr, make the rig happy and work the dx. How much loss do I have with 85 ft of RG-213 at a 4:1 swr. Probably not that much. But a tuner/transmatch/coupler/impedance matching device is a necessary evil to keep my solid state rig happy. The bottom line is all I have done is make my solid state rig happy. And, I work the dx with no trouble. I'm referring to using an antenna that is made for that band. Do I still have the high swr? Sure, but I have made my rig happy and worked the dx. Is this ideal? No, but those of us that work from one end of the band to another know there are very few antenna farms the average ham can afford, or have room for, that allows that luxury. A 75m dipole fed with coax is IMO a poor choice as a multi band antenna. Feed it with 450 ohm ladder line, and you at least have your power reaching the antenna. You'll get some weird lobes, but an antenna like that is still decent (not perfect) between 75 & 20 meters. In other words, yes a resonante antenna would be great to have on all bands and all frequencies. Very few of us have that situation so you do the best you can with what you have. What is really funny to hear, or maybe sad depending on how you look at it, is to hear someone on 75 meters talking about how much better he would probably get out when he trims his dipole to get a 1:1 match instead of the 1.5:1 he has now! I don't have time to read all the responses on here, as I have other things in life that have to be done. Do the best you can with your antenna system, but don't be afraid to step out of the box either. A little! All my comments pertain to HF not VHF/UHF! 73 and enjoy ham radio! Mike, K9MI
KD2BD2007-03-06
RE: Benchmarks
N3OX wrote:

> Total loss in the W9CF tuner simulator to match the 5-j14 impedance at the shack end of the coax, 1.8dB.

That still seems pretty excessive, Dan. That's 34 watts of RF lost to heat for every 100 watts applied.

Wow!

If 100 watts were applied to the tuner for 5 solid minutes, would the coil get as hot as if we applied a 40 watt soldering iron to it for the same length of time?

And think about the inductor in your tube final's Pi Network, and ALL the inductors in the final stage of your solid state transmitter. Should we eliminate those, too?

Maybe we've all been running QRP the whole time.

CQ COMMON SENSE CALLING CQ COMMON SENSE... :-)


73, de John, KD2BD
Reply to a comment by : N3OX on 2007-03-05

Dipole cut for resonance at 3.53MHz, 50+j0 impedance at 3.9MHz is 75+j188, an SWR on 50 ohm line of 9.87. Total loss in 40 feet of RG-213 at this frequency and mismatch, 0.55dB. Total loss in the W9CF tuner simulator to match the 5-j14 impedance at the shack end of the coax, 1.8dB. That's 2.3dB total loss in the tuner plus the coax with a Q=100 coil in the tuner. What's 2.3dB on 75m phone? You think that matters much? It's the simplest way to stretch your 80m dipole to cover the whole band. - - - - - - There are plenty of examples that can be cooked up where the tuner at the shack end of the coax loses 3dB or 7dB or 12dB, but all it takes is one little counterexample... Dan
Reply to a comment by : MLMAN_EE on 2007-03-05

Geez...how would they know what was in your tuner? do you have some special built tuner with magical dilithum crystals? Its a basic T-Network tuner, vari. cap on input, hooked to an inductor, with a vari. cap on the output. The bigger the inductor the better, but I doubt you have a 1' diameter inductor in your box. 3db is pretty serious loss and thats before any type of line loss, and/or antenna loss. Coax adds insult to injury, open lead probably won't add to much more, but still some. QRP man! But that is ok, as you can work the world with QRP, but you sure are wasting a lot of power getting to your lossy antenna system. PUT MORE FIRE INTO THE WIRE, BYPASS THAT DAMN TUNER!
Reply to a comment by : N4KC on 2007-03-05

Man! These guys are good! Not only do they have a nice interactive website, with knobs you can crank and everything, but they also know what the loss is in MY tuner! How do they do that? How do they know what kind of components are in MY tuner? Or what the inductor (the primary source of loss) is inside MY tuner? The things they can do with cookies these days! Maybe they can also tell me the temperature in MY freezer so my spumoni won't get soft! Don N4KC www.donkeith.com/n4kc.htm
Reply to a comment by : MLMAN_EE on 2007-03-05

Here is a GREAT link that will actually show you what the losses are in your tuner, located in your shack. It is an actual T network tuner, you can spin the knobs and actually tune it. In the upper left hand corner it will show you you actual loss. I think a lot of will be surprised at what the losses REALLY are! 2 to 8DB loss in the tuner. Shows what W4LGH was talking about. Now take this loss in your tuner, then if using COAX add in that loss, then the loss of you antenna not being resonant, and what are you doing... Sounds a little ABSURD to me to use a tuner hooked to coax in your shack. Unless you are happy running QRP all the time, because thats what you are doing. Check out the link and see for yourself... http://fermi.la.asu.edu/w9cf/tuner/tuner.html Lifes to short to run QRP!
Reply to a comment by : W4EF on 2007-03-04

K9MI >> But if I'm using an antenna made for the band I'm using, but not the portion of the band, I can still have a fairly high swr, make the rig happy and work the dx. How much loss do I have with 85 ft of RG-213 at a 4:1 swr. Probably not that much. But a tuner/transmatch/coupler/impedance matching device is a necessary evil to keep my solid state rig happy. << It depends a little bit on the phase angle of the impedance at the antenna terminals, but per N6BV's TLW, the additional loss due to the 4:1 mis-match on the coax will be a whopping 0.5 dB (~10% of the incident power)!! There will be a bit more loss in the tuner (mostly in the inductor), but probably not much more than 0.1dB. So you are talking about what roughly amounts to a 0.6dB compromise in the system efficiency by tuning from the shack. Your rig if it uses a solid state final PA probably puts out at least 6dB more power when it sees a good match vs 4:1, so in terms of using the tuner in the shack versus doing nothing at all, you are likely getting a 5 or 6 dB net improvement by using the tuner. The biggest performance factor, of course, will be how the pattern of the yagi changes as you go from SSB down to CW. Without some modeling, that's anybody's guess (could be worse, could be better, could be the same). Also it could be better in terms of gain, but worse in terms of sidelobes, or vice versa. Mike, your situtation of using a tribander tuned for SSB in the CW segment of band with a solid state rig is a perfect example of where using a tuner in the shack makes decent sense. 73, Mike W4EF..................................
Reply to a comment by : K9MI on 2007-03-03

A very lively and intense subject! What I do know, is that my run of the mill, 3 element tribander was assembled for the phone band. By the time I get into the lower portion of the cw band, my swr is 4:1, maybe more. With the use of an outboard tuner, it can be adjusted to where my solid state rig is now looking at a 1:1 match, not the 4:1 plus match. More then likely, the person with an antenna of the same variety is louder to the dx station then I am. Maybe not. Is my swr still 4:1? Yep. But if I'm using an antenna made for the band I'm using, but not the portion of the band, I can still have a fairly high swr, make the rig happy and work the dx. How much loss do I have with 85 ft of RG-213 at a 4:1 swr. Probably not that much. But a tuner/transmatch/coupler/impedance matching device is a necessary evil to keep my solid state rig happy. The bottom line is all I have done is make my solid state rig happy. And, I work the dx with no trouble. I'm referring to using an antenna that is made for that band. Do I still have the high swr? Sure, but I have made my rig happy and worked the dx. Is this ideal? No, but those of us that work from one end of the band to another know there are very few antenna farms the average ham can afford, or have room for, that allows that luxury. A 75m dipole fed with coax is IMO a poor choice as a multi band antenna. Feed it with 450 ohm ladder line, and you at least have your power reaching the antenna. You'll get some weird lobes, but an antenna like that is still decent (not perfect) between 75 & 20 meters. In other words, yes a resonante antenna would be great to have on all bands and all frequencies. Very few of us have that situation so you do the best you can with what you have. What is really funny to hear, or maybe sad depending on how you look at it, is to hear someone on 75 meters talking about how much better he would probably get out when he trims his dipole to get a 1:1 match instead of the 1.5:1 he has now! I don't have time to read all the responses on here, as I have other things in life that have to be done. Do the best you can with your antenna system, but don't be afraid to step out of the box either. A little! All my comments pertain to HF not VHF/UHF! 73 and enjoy ham radio! Mike, K9MI
MLMAN_EE2007-03-06
RE: Benchmarks
Its an OK "make due" a band-aid sorta speak. everyone want to continue to use the best of the best, and MOST out there don't have the best of the best. How about the guy who has 150' of RG-8X or worse, RG-58 running to his 80m dipole. Thats a lot of loss! It is also the more typical example out there. Not everyone has the luxury of short, low loss coax runs.

You guys have done more to HURT amateur radio by making up these "perfect" examples on installs and making a bunch of hams think its ok to do this, when they have QRP levels being radiated.

And its too late now, the damage has been done, they don't know who to believe anymore. So I sincerely hope all you you are very happy with yourselves and feel good about your super knowledge.

A simple parallel dipole, which is no more than a log periodic antenna is a very good antenna, easy to build, and you can set it up with the bands you want, or all of them. Uwe 100' or less RG8X or better, no tuner, and you'll get more power in the air, and better receive, and spend less money.

these hams with 4 letters in their calls need to start thinking outside the box! Ham radio around the country isn't what it is at your house. Not all hams can afford to buy IC-7800's, 100foot towers, 7/8" hardline, and the big StepIR antennas.

Reply to a comment by : N3OX on 2007-03-05

Dipole cut for resonance at 3.53MHz, 50+j0 impedance at 3.9MHz is 75+j188, an SWR on 50 ohm line of 9.87. Total loss in 40 feet of RG-213 at this frequency and mismatch, 0.55dB. Total loss in the W9CF tuner simulator to match the 5-j14 impedance at the shack end of the coax, 1.8dB. That's 2.3dB total loss in the tuner plus the coax with a Q=100 coil in the tuner. What's 2.3dB on 75m phone? You think that matters much? It's the simplest way to stretch your 80m dipole to cover the whole band. - - - - - - There are plenty of examples that can be cooked up where the tuner at the shack end of the coax loses 3dB or 7dB or 12dB, but all it takes is one little counterexample... Dan
Reply to a comment by : MLMAN_EE on 2007-03-05

Geez...how would they know what was in your tuner? do you have some special built tuner with magical dilithum crystals? Its a basic T-Network tuner, vari. cap on input, hooked to an inductor, with a vari. cap on the output. The bigger the inductor the better, but I doubt you have a 1' diameter inductor in your box. 3db is pretty serious loss and thats before any type of line loss, and/or antenna loss. Coax adds insult to injury, open lead probably won't add to much more, but still some. QRP man! But that is ok, as you can work the world with QRP, but you sure are wasting a lot of power getting to your lossy antenna system. PUT MORE FIRE INTO THE WIRE, BYPASS THAT DAMN TUNER!
Reply to a comment by : N4KC on 2007-03-05

Man! These guys are good! Not only do they have a nice interactive website, with knobs you can crank and everything, but they also know what the loss is in MY tuner! How do they do that? How do they know what kind of components are in MY tuner? Or what the inductor (the primary source of loss) is inside MY tuner? The things they can do with cookies these days! Maybe they can also tell me the temperature in MY freezer so my spumoni won't get soft! Don N4KC www.donkeith.com/n4kc.htm
Reply to a comment by : MLMAN_EE on 2007-03-05

Here is a GREAT link that will actually show you what the losses are in your tuner, located in your shack. It is an actual T network tuner, you can spin the knobs and actually tune it. In the upper left hand corner it will show you you actual loss. I think a lot of will be surprised at what the losses REALLY are! 2 to 8DB loss in the tuner. Shows what W4LGH was talking about. Now take this loss in your tuner, then if using COAX add in that loss, then the loss of you antenna not being resonant, and what are you doing... Sounds a little ABSURD to me to use a tuner hooked to coax in your shack. Unless you are happy running QRP all the time, because thats what you are doing. Check out the link and see for yourself... http://fermi.la.asu.edu/w9cf/tuner/tuner.html Lifes to short to run QRP!
Reply to a comment by : W4EF on 2007-03-04

K9MI >> But if I'm using an antenna made for the band I'm using, but not the portion of the band, I can still have a fairly high swr, make the rig happy and work the dx. How much loss do I have with 85 ft of RG-213 at a 4:1 swr. Probably not that much. But a tuner/transmatch/coupler/impedance matching device is a necessary evil to keep my solid state rig happy. << It depends a little bit on the phase angle of the impedance at the antenna terminals, but per N6BV's TLW, the additional loss due to the 4:1 mis-match on the coax will be a whopping 0.5 dB (~10% of the incident power)!! There will be a bit more loss in the tuner (mostly in the inductor), but probably not much more than 0.1dB. So you are talking about what roughly amounts to a 0.6dB compromise in the system efficiency by tuning from the shack. Your rig if it uses a solid state final PA probably puts out at least 6dB more power when it sees a good match vs 4:1, so in terms of using the tuner in the shack versus doing nothing at all, you are likely getting a 5 or 6 dB net improvement by using the tuner. The biggest performance factor, of course, will be how the pattern of the yagi changes as you go from SSB down to CW. Without some modeling, that's anybody's guess (could be worse, could be better, could be the same). Also it could be better in terms of gain, but worse in terms of sidelobes, or vice versa. Mike, your situtation of using a tribander tuned for SSB in the CW segment of band with a solid state rig is a perfect example of where using a tuner in the shack makes decent sense. 73, Mike W4EF..................................
Reply to a comment by : K9MI on 2007-03-03

A very lively and intense subject! What I do know, is that my run of the mill, 3 element tribander was assembled for the phone band. By the time I get into the lower portion of the cw band, my swr is 4:1, maybe more. With the use of an outboard tuner, it can be adjusted to where my solid state rig is now looking at a 1:1 match, not the 4:1 plus match. More then likely, the person with an antenna of the same variety is louder to the dx station then I am. Maybe not. Is my swr still 4:1? Yep. But if I'm using an antenna made for the band I'm using, but not the portion of the band, I can still have a fairly high swr, make the rig happy and work the dx. How much loss do I have with 85 ft of RG-213 at a 4:1 swr. Probably not that much. But a tuner/transmatch/coupler/impedance matching device is a necessary evil to keep my solid state rig happy. The bottom line is all I have done is make my solid state rig happy. And, I work the dx with no trouble. I'm referring to using an antenna that is made for that band. Do I still have the high swr? Sure, but I have made my rig happy and worked the dx. Is this ideal? No, but those of us that work from one end of the band to another know there are very few antenna farms the average ham can afford, or have room for, that allows that luxury. A 75m dipole fed with coax is IMO a poor choice as a multi band antenna. Feed it with 450 ohm ladder line, and you at least have your power reaching the antenna. You'll get some weird lobes, but an antenna like that is still decent (not perfect) between 75 & 20 meters. In other words, yes a resonante antenna would be great to have on all bands and all frequencies. Very few of us have that situation so you do the best you can with what you have. What is really funny to hear, or maybe sad depending on how you look at it, is to hear someone on 75 meters talking about how much better he would probably get out when he trims his dipole to get a 1:1 match instead of the 1.5:1 he has now! I don't have time to read all the responses on here, as I have other things in life that have to be done. Do the best you can with your antenna system, but don't be afraid to step out of the box either. A little! All my comments pertain to HF not VHF/UHF! 73 and enjoy ham radio! Mike, K9MI
N3OX2007-03-05
RE: Benchmarks
Dipole cut for resonance at 3.53MHz, 50+j0 impedance at 3.9MHz is 75+j188, an SWR on 50 ohm line of 9.87.

Total loss in 40 feet of RG-213 at this frequency and mismatch, 0.55dB.

Total loss in the W9CF tuner simulator to match the 5-j14 impedance at the shack end of the coax, 1.8dB.

That's 2.3dB total loss in the tuner plus the coax with a Q=100 coil in the tuner.

What's 2.3dB on 75m phone? You think that matters much? It's the simplest way to stretch your 80m dipole to cover the whole band.

- - - - - -

There are plenty of examples that can be cooked up where the tuner at the shack end of the coax loses 3dB or 7dB or 12dB, but all it takes is one little counterexample...

Dan
Reply to a comment by : MLMAN_EE on 2007-03-05

Geez...how would they know what was in your tuner? do you have some special built tuner with magical dilithum crystals? Its a basic T-Network tuner, vari. cap on input, hooked to an inductor, with a vari. cap on the output. The bigger the inductor the better, but I doubt you have a 1' diameter inductor in your box. 3db is pretty serious loss and thats before any type of line loss, and/or antenna loss. Coax adds insult to injury, open lead probably won't add to much more, but still some. QRP man! But that is ok, as you can work the world with QRP, but you sure are wasting a lot of power getting to your lossy antenna system. PUT MORE FIRE INTO THE WIRE, BYPASS THAT DAMN TUNER!
Reply to a comment by : N4KC on 2007-03-05

Man! These guys are good! Not only do they have a nice interactive website, with knobs you can crank and everything, but they also know what the loss is in MY tuner! How do they do that? How do they know what kind of components are in MY tuner? Or what the inductor (the primary source of loss) is inside MY tuner? The things they can do with cookies these days! Maybe they can also tell me the temperature in MY freezer so my spumoni won't get soft! Don N4KC www.donkeith.com/n4kc.htm
Reply to a comment by : MLMAN_EE on 2007-03-05

Here is a GREAT link that will actually show you what the losses are in your tuner, located in your shack. It is an actual T network tuner, you can spin the knobs and actually tune it. In the upper left hand corner it will show you you actual loss. I think a lot of will be surprised at what the losses REALLY are! 2 to 8DB loss in the tuner. Shows what W4LGH was talking about. Now take this loss in your tuner, then if using COAX add in that loss, then the loss of you antenna not being resonant, and what are you doing... Sounds a little ABSURD to me to use a tuner hooked to coax in your shack. Unless you are happy running QRP all the time, because thats what you are doing. Check out the link and see for yourself... http://fermi.la.asu.edu/w9cf/tuner/tuner.html Lifes to short to run QRP!
Reply to a comment by : W4EF on 2007-03-04

K9MI >> But if I'm using an antenna made for the band I'm using, but not the portion of the band, I can still have a fairly high swr, make the rig happy and work the dx. How much loss do I have with 85 ft of RG-213 at a 4:1 swr. Probably not that much. But a tuner/transmatch/coupler/impedance matching device is a necessary evil to keep my solid state rig happy. << It depends a little bit on the phase angle of the impedance at the antenna terminals, but per N6BV's TLW, the additional loss due to the 4:1 mis-match on the coax will be a whopping 0.5 dB (~10% of the incident power)!! There will be a bit more loss in the tuner (mostly in the inductor), but probably not much more than 0.1dB. So you are talking about what roughly amounts to a 0.6dB compromise in the system efficiency by tuning from the shack. Your rig if it uses a solid state final PA probably puts out at least 6dB more power when it sees a good match vs 4:1, so in terms of using the tuner in the shack versus doing nothing at all, you are likely getting a 5 or 6 dB net improvement by using the tuner. The biggest performance factor, of course, will be how the pattern of the yagi changes as you go from SSB down to CW. Without some modeling, that's anybody's guess (could be worse, could be better, could be the same). Also it could be better in terms of gain, but worse in terms of sidelobes, or vice versa. Mike, your situtation of using a tribander tuned for SSB in the CW segment of band with a solid state rig is a perfect example of where using a tuner in the shack makes decent sense. 73, Mike W4EF..................................
Reply to a comment by : K9MI on 2007-03-03

A very lively and intense subject! What I do know, is that my run of the mill, 3 element tribander was assembled for the phone band. By the time I get into the lower portion of the cw band, my swr is 4:1, maybe more. With the use of an outboard tuner, it can be adjusted to where my solid state rig is now looking at a 1:1 match, not the 4:1 plus match. More then likely, the person with an antenna of the same variety is louder to the dx station then I am. Maybe not. Is my swr still 4:1? Yep. But if I'm using an antenna made for the band I'm using, but not the portion of the band, I can still have a fairly high swr, make the rig happy and work the dx. How much loss do I have with 85 ft of RG-213 at a 4:1 swr. Probably not that much. But a tuner/transmatch/coupler/impedance matching device is a necessary evil to keep my solid state rig happy. The bottom line is all I have done is make my solid state rig happy. And, I work the dx with no trouble. I'm referring to using an antenna that is made for that band. Do I still have the high swr? Sure, but I have made my rig happy and worked the dx. Is this ideal? No, but those of us that work from one end of the band to another know there are very few antenna farms the average ham can afford, or have room for, that allows that luxury. A 75m dipole fed with coax is IMO a poor choice as a multi band antenna. Feed it with 450 ohm ladder line, and you at least have your power reaching the antenna. You'll get some weird lobes, but an antenna like that is still decent (not perfect) between 75 & 20 meters. In other words, yes a resonante antenna would be great to have on all bands and all frequencies. Very few of us have that situation so you do the best you can with what you have. What is really funny to hear, or maybe sad depending on how you look at it, is to hear someone on 75 meters talking about how much better he would probably get out when he trims his dipole to get a 1:1 match instead of the 1.5:1 he has now! I don't have time to read all the responses on here, as I have other things in life that have to be done. Do the best you can with your antenna system, but don't be afraid to step out of the box either. A little! All my comments pertain to HF not VHF/UHF! 73 and enjoy ham radio! Mike, K9MI
MLMAN_EE2007-03-05
RE: Benchmarks
Geez...how would they know what was in your tuner? do you have some special built tuner with magical dilithum crystals? Its a basic T-Network tuner, vari. cap on input, hooked to an inductor, with a vari. cap on the output. The bigger the inductor the better, but I doubt you have a 1' diameter inductor in your box. 3db is pretty serious loss and thats before any type of line loss, and/or antenna loss.
Coax adds insult to injury, open lead probably won't add to much more, but still some. QRP man! But that is ok, as you can work the world with QRP, but you sure are wasting a lot of power getting to your lossy antenna system.

PUT MORE FIRE INTO THE WIRE, BYPASS THAT DAMN TUNER!
Reply to a comment by : N4KC on 2007-03-05

Man! These guys are good! Not only do they have a nice interactive website, with knobs you can crank and everything, but they also know what the loss is in MY tuner! How do they do that? How do they know what kind of components are in MY tuner? Or what the inductor (the primary source of loss) is inside MY tuner? The things they can do with cookies these days! Maybe they can also tell me the temperature in MY freezer so my spumoni won't get soft! Don N4KC www.donkeith.com/n4kc.htm
Reply to a comment by : MLMAN_EE on 2007-03-05

Here is a GREAT link that will actually show you what the losses are in your tuner, located in your shack. It is an actual T network tuner, you can spin the knobs and actually tune it. In the upper left hand corner it will show you you actual loss. I think a lot of will be surprised at what the losses REALLY are! 2 to 8DB loss in the tuner. Shows what W4LGH was talking about. Now take this loss in your tuner, then if using COAX add in that loss, then the loss of you antenna not being resonant, and what are you doing... Sounds a little ABSURD to me to use a tuner hooked to coax in your shack. Unless you are happy running QRP all the time, because thats what you are doing. Check out the link and see for yourself... http://fermi.la.asu.edu/w9cf/tuner/tuner.html Lifes to short to run QRP!
Reply to a comment by : W4EF on 2007-03-04

K9MI >> But if I'm using an antenna made for the band I'm using, but not the portion of the band, I can still have a fairly high swr, make the rig happy and work the dx. How much loss do I have with 85 ft of RG-213 at a 4:1 swr. Probably not that much. But a tuner/transmatch/coupler/impedance matching device is a necessary evil to keep my solid state rig happy. << It depends a little bit on the phase angle of the impedance at the antenna terminals, but per N6BV's TLW, the additional loss due to the 4:1 mis-match on the coax will be a whopping 0.5 dB (~10% of the incident power)!! There will be a bit more loss in the tuner (mostly in the inductor), but probably not much more than 0.1dB. So you are talking about what roughly amounts to a 0.6dB compromise in the system efficiency by tuning from the shack. Your rig if it uses a solid state final PA probably puts out at least 6dB more power when it sees a good match vs 4:1, so in terms of using the tuner in the shack versus doing nothing at all, you are likely getting a 5 or 6 dB net improvement by using the tuner. The biggest performance factor, of course, will be how the pattern of the yagi changes as you go from SSB down to CW. Without some modeling, that's anybody's guess (could be worse, could be better, could be the same). Also it could be better in terms of gain, but worse in terms of sidelobes, or vice versa. Mike, your situtation of using a tribander tuned for SSB in the CW segment of band with a solid state rig is a perfect example of where using a tuner in the shack makes decent sense. 73, Mike W4EF..................................
Reply to a comment by : K9MI on 2007-03-03

A very lively and intense subject! What I do know, is that my run of the mill, 3 element tribander was assembled for the phone band. By the time I get into the lower portion of the cw band, my swr is 4:1, maybe more. With the use of an outboard tuner, it can be adjusted to where my solid state rig is now looking at a 1:1 match, not the 4:1 plus match. More then likely, the person with an antenna of the same variety is louder to the dx station then I am. Maybe not. Is my swr still 4:1? Yep. But if I'm using an antenna made for the band I'm using, but not the portion of the band, I can still have a fairly high swr, make the rig happy and work the dx. How much loss do I have with 85 ft of RG-213 at a 4:1 swr. Probably not that much. But a tuner/transmatch/coupler/impedance matching device is a necessary evil to keep my solid state rig happy. The bottom line is all I have done is make my solid state rig happy. And, I work the dx with no trouble. I'm referring to using an antenna that is made for that band. Do I still have the high swr? Sure, but I have made my rig happy and worked the dx. Is this ideal? No, but those of us that work from one end of the band to another know there are very few antenna farms the average ham can afford, or have room for, that allows that luxury. A 75m dipole fed with coax is IMO a poor choice as a multi band antenna. Feed it with 450 ohm ladder line, and you at least have your power reaching the antenna. You'll get some weird lobes, but an antenna like that is still decent (not perfect) between 75 & 20 meters. In other words, yes a resonante antenna would be great to have on all bands and all frequencies. Very few of us have that situation so you do the best you can with what you have. What is really funny to hear, or maybe sad depending on how you look at it, is to hear someone on 75 meters talking about how much better he would probably get out when he trims his dipole to get a 1:1 match instead of the 1.5:1 he has now! I don't have time to read all the responses on here, as I have other things in life that have to be done. Do the best you can with your antenna system, but don't be afraid to step out of the box either. A little! All my comments pertain to HF not VHF/UHF! 73 and enjoy ham radio! Mike, K9MI
N4KC2007-03-05
RE: Benchmarks
Man! These guys are good! Not only do they have a nice interactive website, with knobs you can crank and everything, but they also know what the loss is in MY tuner!

How do they do that? How do they know what kind of components are in MY tuner? Or what the inductor (the primary source of loss) is inside MY tuner?

The things they can do with cookies these days! Maybe they can also tell me the temperature in MY freezer so my spumoni won't get soft!

Don N4KC
www.donkeith.com/n4kc.htm
Reply to a comment by : MLMAN_EE on 2007-03-05

Here is a GREAT link that will actually show you what the losses are in your tuner, located in your shack. It is an actual T network tuner, you can spin the knobs and actually tune it. In the upper left hand corner it will show you you actual loss. I think a lot of will be surprised at what the losses REALLY are! 2 to 8DB loss in the tuner. Shows what W4LGH was talking about. Now take this loss in your tuner, then if using COAX add in that loss, then the loss of you antenna not being resonant, and what are you doing... Sounds a little ABSURD to me to use a tuner hooked to coax in your shack. Unless you are happy running QRP all the time, because thats what you are doing. Check out the link and see for yourself... http://fermi.la.asu.edu/w9cf/tuner/tuner.html Lifes to short to run QRP!
Reply to a comment by : W4EF on 2007-03-04

K9MI >> But if I'm using an antenna made for the band I'm using, but not the portion of the band, I can still have a fairly high swr, make the rig happy and work the dx. How much loss do I have with 85 ft of RG-213 at a 4:1 swr. Probably not that much. But a tuner/transmatch/coupler/impedance matching device is a necessary evil to keep my solid state rig happy. << It depends a little bit on the phase angle of the impedance at the antenna terminals, but per N6BV's TLW, the additional loss due to the 4:1 mis-match on the coax will be a whopping 0.5 dB (~10% of the incident power)!! There will be a bit more loss in the tuner (mostly in the inductor), but probably not much more than 0.1dB. So you are talking about what roughly amounts to a 0.6dB compromise in the system efficiency by tuning from the shack. Your rig if it uses a solid state final PA probably puts out at least 6dB more power when it sees a good match vs 4:1, so in terms of using the tuner in the shack versus doing nothing at all, you are likely getting a 5 or 6 dB net improvement by using the tuner. The biggest performance factor, of course, will be how the pattern of the yagi changes as you go from SSB down to CW. Without some modeling, that's anybody's guess (could be worse, could be better, could be the same). Also it could be better in terms of gain, but worse in terms of sidelobes, or vice versa. Mike, your situtation of using a tribander tuned for SSB in the CW segment of band with a solid state rig is a perfect example of where using a tuner in the shack makes decent sense. 73, Mike W4EF..................................
Reply to a comment by : K9MI on 2007-03-03

A very lively and intense subject! What I do know, is that my run of the mill, 3 element tribander was assembled for the phone band. By the time I get into the lower portion of the cw band, my swr is 4:1, maybe more. With the use of an outboard tuner, it can be adjusted to where my solid state rig is now looking at a 1:1 match, not the 4:1 plus match. More then likely, the person with an antenna of the same variety is louder to the dx station then I am. Maybe not. Is my swr still 4:1? Yep. But if I'm using an antenna made for the band I'm using, but not the portion of the band, I can still have a fairly high swr, make the rig happy and work the dx. How much loss do I have with 85 ft of RG-213 at a 4:1 swr. Probably not that much. But a tuner/transmatch/coupler/impedance matching device is a necessary evil to keep my solid state rig happy. The bottom line is all I have done is make my solid state rig happy. And, I work the dx with no trouble. I'm referring to using an antenna that is made for that band. Do I still have the high swr? Sure, but I have made my rig happy and worked the dx. Is this ideal? No, but those of us that work from one end of the band to another know there are very few antenna farms the average ham can afford, or have room for, that allows that luxury. A 75m dipole fed with coax is IMO a poor choice as a multi band antenna. Feed it with 450 ohm ladder line, and you at least have your power reaching the antenna. You'll get some weird lobes, but an antenna like that is still decent (not perfect) between 75 & 20 meters. In other words, yes a resonante antenna would be great to have on all bands and all frequencies. Very few of us have that situation so you do the best you can with what you have. What is really funny to hear, or maybe sad depending on how you look at it, is to hear someone on 75 meters talking about how much better he would probably get out when he trims his dipole to get a 1:1 match instead of the 1.5:1 he has now! I don't have time to read all the responses on here, as I have other things in life that have to be done. Do the best you can with your antenna system, but don't be afraid to step out of the box either. A little! All my comments pertain to HF not VHF/UHF! 73 and enjoy ham radio! Mike, K9MI
MLMAN_EE2007-03-05
RE: Benchmarks
Here is a GREAT link that will actually show you what the losses are in your tuner, located in your shack.
It is an actual T network tuner, you can spin the knobs and actually tune it. In the upper left hand corner it will show you you actual loss. I think a lot of will be surprised at what the losses REALLY are! 2 to 8DB loss in the tuner.

Shows what W4LGH was talking about. Now take this loss in your tuner, then if using COAX add in that loss, then the loss of you antenna not being resonant, and what are you doing... Sounds a little
ABSURD to me to use a tuner hooked to coax in your shack. Unless you are happy running QRP all the time, because thats what you are doing.

Check out the link and see for yourself...

http://fermi.la.asu.edu/w9cf/tuner/tuner.html

Lifes to short to run QRP!
Reply to a comment by : W4EF on 2007-03-04

K9MI >> But if I'm using an antenna made for the band I'm using, but not the portion of the band, I can still have a fairly high swr, make the rig happy and work the dx. How much loss do I have with 85 ft of RG-213 at a 4:1 swr. Probably not that much. But a tuner/transmatch/coupler/impedance matching device is a necessary evil to keep my solid state rig happy. << It depends a little bit on the phase angle of the impedance at the antenna terminals, but per N6BV's TLW, the additional loss due to the 4:1 mis-match on the coax will be a whopping 0.5 dB (~10% of the incident power)!! There will be a bit more loss in the tuner (mostly in the inductor), but probably not much more than 0.1dB. So you are talking about what roughly amounts to a 0.6dB compromise in the system efficiency by tuning from the shack. Your rig if it uses a solid state final PA probably puts out at least 6dB more power when it sees a good match vs 4:1, so in terms of using the tuner in the shack versus doing nothing at all, you are likely getting a 5 or 6 dB net improvement by using the tuner. The biggest performance factor, of course, will be how the pattern of the yagi changes as you go from SSB down to CW. Without some modeling, that's anybody's guess (could be worse, could be better, could be the same). Also it could be better in terms of gain, but worse in terms of sidelobes, or vice versa. Mike, your situtation of using a tribander tuned for SSB in the CW segment of band with a solid state rig is a perfect example of where using a tuner in the shack makes decent sense. 73, Mike W4EF..................................
Reply to a comment by : K9MI on 2007-03-03

A very lively and intense subject! What I do know, is that my run of the mill, 3 element tribander was assembled for the phone band. By the time I get into the lower portion of the cw band, my swr is 4:1, maybe more. With the use of an outboard tuner, it can be adjusted to where my solid state rig is now looking at a 1:1 match, not the 4:1 plus match. More then likely, the person with an antenna of the same variety is louder to the dx station then I am. Maybe not. Is my swr still 4:1? Yep. But if I'm using an antenna made for the band I'm using, but not the portion of the band, I can still have a fairly high swr, make the rig happy and work the dx. How much loss do I have with 85 ft of RG-213 at a 4:1 swr. Probably not that much. But a tuner/transmatch/coupler/impedance matching device is a necessary evil to keep my solid state rig happy. The bottom line is all I have done is make my solid state rig happy. And, I work the dx with no trouble. I'm referring to using an antenna that is made for that band. Do I still have the high swr? Sure, but I have made my rig happy and worked the dx. Is this ideal? No, but those of us that work from one end of the band to another know there are very few antenna farms the average ham can afford, or have room for, that allows that luxury. A 75m dipole fed with coax is IMO a poor choice as a multi band antenna. Feed it with 450 ohm ladder line, and you at least have your power reaching the antenna. You'll get some weird lobes, but an antenna like that is still decent (not perfect) between 75 & 20 meters. In other words, yes a resonante antenna would be great to have on all bands and all frequencies. Very few of us have that situation so you do the best you can with what you have. What is really funny to hear, or maybe sad depending on how you look at it, is to hear someone on 75 meters talking about how much better he would probably get out when he trims his dipole to get a 1:1 match instead of the 1.5:1 he has now! I don't have time to read all the responses on here, as I have other things in life that have to be done. Do the best you can with your antenna system, but don't be afraid to step out of the box either. A little! All my comments pertain to HF not VHF/UHF! 73 and enjoy ham radio! Mike, K9MI
W4EF2007-03-04
RE: Benchmarks
K9MI

>> But if I'm using an antenna made for the band I'm using, but not the portion of the band, I can still have a fairly high swr, make the rig happy and work the dx. How much loss do I have with 85 ft of RG-213 at a 4:1 swr. Probably not that much. But a tuner/transmatch/coupler/impedance matching device is a necessary evil to keep my solid state rig happy. <<

It depends a little bit on the phase angle of the impedance at the antenna terminals, but per N6BV's TLW, the additional loss due to the 4:1 mis-match on the coax will be a whopping 0.5 dB (~10% of the incident power)!! There will be a bit more loss in the tuner (mostly in the inductor), but probably not much more than 0.1dB. So you are talking about what roughly amounts to a 0.6dB compromise in the system efficiency by tuning from the shack. Your rig if it uses a solid state final PA probably puts out at least 6dB more power when it sees a good match vs 4:1, so in terms of using the tuner in the shack versus doing nothing at all, you are likely getting a 5 or 6 dB net improvement by using the tuner.

The biggest performance factor, of course, will be how the pattern of the yagi changes as you go from SSB down to CW. Without some modeling, that's anybody's guess (could be worse, could be better, could be the same). Also it could be better in terms of gain, but worse in terms of sidelobes, or vice versa.

Mike, your situtation of using a tribander tuned for SSB in the CW segment of band with a solid state rig is a perfect example of where using a tuner in the shack makes decent sense.

73, Mike W4EF..................................
Reply to a comment by : K9MI on 2007-03-03

A very lively and intense subject! What I do know, is that my run of the mill, 3 element tribander was assembled for the phone band. By the time I get into the lower portion of the cw band, my swr is 4:1, maybe more. With the use of an outboard tuner, it can be adjusted to where my solid state rig is now looking at a 1:1 match, not the 4:1 plus match. More then likely, the person with an antenna of the same variety is louder to the dx station then I am. Maybe not. Is my swr still 4:1? Yep. But if I'm using an antenna made for the band I'm using, but not the portion of the band, I can still have a fairly high swr, make the rig happy and work the dx. How much loss do I have with 85 ft of RG-213 at a 4:1 swr. Probably not that much. But a tuner/transmatch/coupler/impedance matching device is a necessary evil to keep my solid state rig happy. The bottom line is all I have done is make my solid state rig happy. And, I work the dx with no trouble. I'm referring to using an antenna that is made for that band. Do I still have the high swr? Sure, but I have made my rig happy and worked the dx. Is this ideal? No, but those of us that work from one end of the band to another know there are very few antenna farms the average ham can afford, or have room for, that allows that luxury. A 75m dipole fed with coax is IMO a poor choice as a multi band antenna. Feed it with 450 ohm ladder line, and you at least have your power reaching the antenna. You'll get some weird lobes, but an antenna like that is still decent (not perfect) between 75 & 20 meters. In other words, yes a resonante antenna would be great to have on all bands and all frequencies. Very few of us have that situation so you do the best you can with what you have. What is really funny to hear, or maybe sad depending on how you look at it, is to hear someone on 75 meters talking about how much better he would probably get out when he trims his dipole to get a 1:1 match instead of the 1.5:1 he has now! I don't have time to read all the responses on here, as I have other things in life that have to be done. Do the best you can with your antenna system, but don't be afraid to step out of the box either. A little! All my comments pertain to HF not VHF/UHF! 73 and enjoy ham radio! Mike, K9MI
N4KC2007-03-04
RE: Benchmarks
Mike, you echoed the opinions of many on this long but very interesting thread. 4:1 is NOT a high SWR at all, and so long as your radio is okay with it, the loss of output you would suffer in any good quality coax would likely be unnoticed by anyone on the receiving end. Most internal tuners employed by today's modern gear are great for tweaking the match so the rig is happy, yet will not give you a match to something that will burn up your coax.

Coax-fed dipoles are NOT very good multi-band antennas unless the odd harmonic multiples of their fundamental frequencies fall somewhere within or close to other ham bands.

On the other hand, balanced-feedline-fed dipoles work mighty well on a lot of frequencies and bands, eventually (in tiny, tiny portions of a second) radiating almost all the power you give them and, as the operating frequency increases, even adding gain in lobes (and, admittedly creating some nulls, too). SWR is not nearly so much a factor with the latter setup and, so long as the matching device ("tuner" or other) effectively washes out the reactance and couples your rig to the load, you're off and running.

Incidentally, I think there is a pretty good primer in antenna theory contained in the comments on this thread. If you have time to read all the posts--and take every one of them with a grain of salt until you have a chance to read and study other material referenced above--it is a great learning experience!

I only hope this "1:1 SWR or Nothing" mentality will not dissuade newcomers to HF from "hanging some wire and giving it some fire!"

73,

Don N4KC
www.donkeith.com/n4kc.htm
Reply to a comment by : K9MI on 2007-03-03

A very lively and intense subject! What I do know, is that my run of the mill, 3 element tribander was assembled for the phone band. By the time I get into the lower portion of the cw band, my swr is 4:1, maybe more. With the use of an outboard tuner, it can be adjusted to where my solid state rig is now looking at a 1:1 match, not the 4:1 plus match. More then likely, the person with an antenna of the same variety is louder to the dx station then I am. Maybe not. Is my swr still 4:1? Yep. But if I'm using an antenna made for the band I'm using, but not the portion of the band, I can still have a fairly high swr, make the rig happy and work the dx. How much loss do I have with 85 ft of RG-213 at a 4:1 swr. Probably not that much. But a tuner/transmatch/coupler/impedance matching device is a necessary evil to keep my solid state rig happy. The bottom line is all I have done is make my solid state rig happy. And, I work the dx with no trouble. I'm referring to using an antenna that is made for that band. Do I still have the high swr? Sure, but I have made my rig happy and worked the dx. Is this ideal? No, but those of us that work from one end of the band to another know there are very few antenna farms the average ham can afford, or have room for, that allows that luxury. A 75m dipole fed with coax is IMO a poor choice as a multi band antenna. Feed it with 450 ohm ladder line, and you at least have your power reaching the antenna. You'll get some weird lobes, but an antenna like that is still decent (not perfect) between 75 & 20 meters. In other words, yes a resonante antenna would be great to have on all bands and all frequencies. Very few of us have that situation so you do the best you can with what you have. What is really funny to hear, or maybe sad depending on how you look at it, is to hear someone on 75 meters talking about how much better he would probably get out when he trims his dipole to get a 1:1 match instead of the 1.5:1 he has now! I don't have time to read all the responses on here, as I have other things in life that have to be done. Do the best you can with your antenna system, but don't be afraid to step out of the box either. A little! All my comments pertain to HF not VHF/UHF! 73 and enjoy ham radio! Mike, K9MI
K9MI2007-03-03
Benchmarks
A very lively and intense subject!

What I do know, is that my run of the mill, 3 element tribander was assembled for the phone band. By the time I get into the lower portion of the cw band, my swr is 4:1, maybe more.

With the use of an outboard tuner, it can be adjusted to where my solid state rig is now looking at a 1:1 match, not the 4:1 plus match. More then likely, the person with an antenna of the same variety is louder to the dx station then I am. Maybe not. Is my swr still 4:1? Yep. But if I'm using an antenna made for the band I'm using, but not the portion of the band, I can still have a fairly high swr, make the rig happy and work the dx. How much loss do I have with 85 ft of RG-213 at a 4:1 swr. Probably not that much. But a tuner/transmatch/coupler/impedance matching device is a necessary evil to keep my solid state rig happy.


The bottom line is all I have done is make my solid state rig happy. And, I work the dx with no trouble. I'm referring to using an antenna that is made for that band. Do I still have the high swr? Sure, but I have made my rig happy and worked the dx. Is this ideal? No, but those of us that work from one end of the band to another know there are very few antenna farms the average ham can afford, or have room for, that allows that luxury.

A 75m dipole fed with coax is IMO a poor choice as a multi band antenna. Feed it with 450 ohm ladder line, and you at least have your power reaching the antenna. You'll get some weird lobes, but an antenna like that is still decent (not perfect) between 75 & 20 meters.

In other words, yes a resonante antenna would be great to have on all bands and all frequencies. Very few of us have that situation so you do the best you can with what you have.

What is really funny to hear, or maybe sad depending on how you look at it, is to hear someone on 75 meters talking about how much better he would probably get out when he trims his dipole to get a 1:1 match instead of the 1.5:1 he has now!

I don't have time to read all the responses on here, as I have other things in life that have to be done. Do the best you can with your antenna system, but don't be afraid to step out of the box either. A little! All my comments pertain to HF not VHF/UHF!

73 and enjoy ham radio! Mike, K9MI

K0FF2007-03-02
RE: Benchmarks
"Now can someone tell me how I am going to put 5 reasonant dipoles on only a 1 acre lot?? I dont want no trap dipole or fan dipole either. How do you guys do it if you just have a 50 x 100 ft city lot? There MUST be a trick here I am mising. HELP I wannna throw out that damn ABSURD tuner. Where is W4LGH when you need him?

Stan K9IUQ "

Yes for sure. One way is to use traps. I recommend traps made form coax cable. I have tried about every type of trap that I can home-brew and the coax cables ones have the best bandwidth characteristics. Another was is the parallel dipole. Several bands can be run from one feedpoint. Not all bands work together though. I have an article out there somewhere called the "nearly invisible antenna" that was "designed" for urban home installations. I put quotes around "design" because my designing is done with a wire cutter and a spool of wire. The coax traps also work great on a tree-hung wire antenna. I made one for 160 through 17M using a combination of trapped elements and parallel elements in an inverted L arrangement. As long as the current node is vertical, the antenna is a vertical. The top part is just for loading since it is at current minimum.. Worked great. Tuned radials, at least 4 per band, more than 8 is a waste, so 6 is about ideal. Put RF choke on coax at antenna base.A series capacitor that is motorized allows whole band coverage with no tuner in the shack.

Geo>K0FF
Reply to a comment by : K9IUQ on 2007-02-28

Practical Considerations and the Radio Amateur Ok I give up. W4LGH is right, everyone else is wrong. I am going to take down my 130ft centerfed antenna with open feeders (and a ABSURD antenna tuner)that I use for 75,60,40,30 mtrs. And put up REASONANT coax fed dipoles for each band. But wait I know from past experience a dipole won't cover the whole 75 mtr band. I want to to talk to my buddies on the high end of 75 AND pound brass on 3515. So I will need 2 antennas for 75mtr because no way am I going to use the ABSURD antenna tuner and give up half my signal. I surveyed my lot this morning. I have 1 1/2 acre but 1/2 acre is in woods and unsuitable for antennas. I also have a large metal pole barn, which I know will not help my antennas , so I have to stay away from that. Also my powerline is overhead coming in the front of the house. Gotta stay away from that too, plus my xyl doesn't want ANY antenna in the front yard.Also I have a tower with a Log Peridioc beam, I dont want to miss up my dx on 20 mtrs so I have to stay away from that too. Now can someone tell me how I am going to put 5 reasonant dipoles on only a 1 acre lot?? I dont want no trap dipole or fan dipole either. How do you guys do it if you just have a 50 x 100 ft city lot? There MUST be a trick here I am mising. HELP I wannna throw out that damn ABSURD tuner. Where is W4LGH when you need him? Stan K9IUQ
MLMAN_EE2007-03-02
RE: Benchmarks
Well since you have figured me out, I might as well log in under my own acct. You all are a bunch of freeking idiots! Thought W4LGH would have been a good cover, but you idiots figured me out.

Billy Bad Ass! Gotya! hahahahahahahahahahaha..

Reply to a comment by : K1DA on 2007-03-02

I'm still waiting for a bandwidth vs resonance explanation from "resonance man".
Reply to a comment by : K9IUQ on 2007-03-02

KD2BD wrote; it's hard to believe it's the same person. ........................................................ Its like he has changed completely. W4GLH says to me, among other VERY NASTY comments: "so the reason they put antenna tuners in radios is so F#$KING IDIOTS like you will BUY THEM!! " BUT A MONTH EARLIER HE WROTE Article on Eham titled Fraternal Brotherhood of Hams.Direct quote no spin. From W4LGH: "I have always been told it is OK to disagree with a theory/idea, but on here it becomes a MAJOR event with slanderous comments and name-calling. I fail to see or understand why someone would get so upset about a comment and resort to these immature ways. If you don't like something, its OK to say, I don't like it and move on." ........................................................ IS there anything we can believe from W4LGH??????????? Stan K9IUQ
K1DA2007-03-02
RE: Benchmarks
I'm still waiting for a bandwidth vs resonance explanation from "resonance man".
Reply to a comment by : K9IUQ on 2007-03-02

KD2BD wrote; it's hard to believe it's the same person. ........................................................ Its like he has changed completely. W4GLH says to me, among other VERY NASTY comments: "so the reason they put antenna tuners in radios is so F#$KING IDIOTS like you will BUY THEM!! " BUT A MONTH EARLIER HE WROTE Article on Eham titled Fraternal Brotherhood of Hams.Direct quote no spin. From W4LGH: "I have always been told it is OK to disagree with a theory/idea, but on here it becomes a MAJOR event with slanderous comments and name-calling. I fail to see or understand why someone would get so upset about a comment and resort to these immature ways. If you don't like something, its OK to say, I don't like it and move on." ........................................................ IS there anything we can believe from W4LGH??????????? Stan K9IUQ
MLMAN_EE2007-03-02
RE: Benchmarks
HAHAHAHAHAHAHA...I can be anywhere...
Reply to a comment by : W4LGH on 2007-03-02

Boy is he gonna be pissed when he finds out! But you'll never catch the MLMAN_EE...}}}POOF{{{
Reply to a comment by : K9IUQ on 2007-03-02

K6IOU says: If he is, indeed, a troll . . . he has been very effective. ..................................................... I thought about that myself, as no Extra Class ham could be as mis-informed as Al on antennas, especially a Broadcast Engineer. I think he may be Kurt N. Sterba doing uncover work for WorldRadio magazine......... Stan K9IUQ
W4LGH2007-03-02
RE: Benchmarks
Boy is he gonna be pissed when he finds out!
But you'll never catch the MLMAN_EE...}}}POOF{{{
Reply to a comment by : K9IUQ on 2007-03-02

K6IOU says: If he is, indeed, a troll . . . he has been very effective. ..................................................... I thought about that myself, as no Extra Class ham could be as mis-informed as Al on antennas, especially a Broadcast Engineer. I think he may be Kurt N. Sterba doing uncover work for WorldRadio magazine......... Stan K9IUQ
K9IUQ2007-03-02
Benchmarks
KD2BD wrote; it's hard to believe it's the same person.
........................................................
Its like he has changed completely.

W4GLH says to me, among other VERY NASTY comments:

"so the reason they put antenna tuners in radios is so F#$KING IDIOTS like you will BUY THEM!! "


BUT A MONTH EARLIER HE WROTE



Article on Eham titled Fraternal Brotherhood of Hams.Direct quote no spin. From W4LGH:

"I have always been told it is OK to disagree with a theory/idea, but on here it becomes a MAJOR event with slanderous comments and name-calling. I fail to see or understand why someone would get so upset about a comment and resort to these immature ways. If you don't like something, its OK to say, I don't like it and move on."
........................................................

IS there anything we can believe from W4LGH???????????

Stan K9IUQ

K9IUQ2007-03-02
Benchmarks
K6IOU says: If he is, indeed, a troll . . . he has been very effective.

.....................................................
I thought about that myself, as no Extra Class ham could be as mis-informed as Al on antennas, especially a Broadcast Engineer.

I think he may be Kurt N. Sterba doing uncover work for WorldRadio magazine.........


Stan K9IUQ
KD2BD2007-03-02
RE: Benchmarks
K6IOU wrote:

> Has anyone on this forum wondered if maybe Al [W4LGH]
> really isn't as confused about all this as it
> appears? Maybe he is a classic internet 'troll'.

I don't know, Don.

On January 28th in another thread he stated:

> AMEN! What can I say to that? I know that is how it
> was when I got started, and now in my 50's I still
> look up to those who know more about something than
> I do. I also want to learn from them, pick their
> brain for all the information I can get.

Today he's saying:

> Thats it...NO you will NOT change my knowledge on this

It's hard to believe it's the same person.


73, de John, KD2BD
Reply to a comment by : K6IOU on 2007-03-02

Has anyone on this forum wondered if maybe Al [W4LGH] really isn't as confused about all this as it appears? Maybe he is a classic internet 'troll'. His apparent 'grasp' of all of this is so out-of-touch with reality that he really can't be taken seriously. If he is, indeed, a troll . . . he has been very effective. This "Benchmarks" discussion has to set some kind of record as to length! If he is 'for real' . . . it is sad indeed. Al, please read the current literature on all of this . . . specifically Maxwell's Reflections II and the ARRL Antenna Handbook. If what is contained in these two references can't convince you of your mis-guided thinking . . . certainly no one on this forum can either. Al . . . how about this: open your copy of the ARRL Antenna Handbook, find a specific 'error' concerning antennas and feedlines . . . and report the Book Edition, page number, and the error to this group. I'd really like to have these errors uncovered and you would be doing a great service to amateur radio. Regards, DON K6IOU
Reply to a comment by : W4LGH on 2007-03-02

John...there simply is no hope for you, I believe you are going to argue when your time is up and they come to get you. Something about reflected years were added back to your total # of years allowed. I have done the experiment you siad, and have NEVER seen additional power on the meter, only the reflected power. And it wasn't talking about reflected power on the feed line, it was talking about reflected power on the antenna, since it was out of resonance and the actual sine wave reflected back will cancel the forward sine wave. But thats ok. I am thru arguing about this, you believe what you want, as they say if you TRUELY believe then it must be so. Have a nice day!
Reply to a comment by : KD2BD on 2007-03-02

W4LGH wrote: > Signals can be canceled by a phase shift. if you > signals that are equal are 180 degs out of phase they > will cancel, null each other out. I can apply 10 mA of DC current through a resistor in one direction, and apply 10 mA of DC current through the resistor in the other direction, and the net current flow through the resistor will be 0 mA. Yes. I agree. But POWER isn't "cancelled" in the process. Current simply isn't being drawn from the voltage sources. > If you look at the wave forms on your ramdon wire, > the reflected signal can be less <= the forward > signal. Any amount of reflected signal, lets say for > example 10% will subtract from the main signal. Only if nothing is done to re-reflect that energy BACK towards the antenna again. The device that does this is the antenna tuner. A 100-watt transmitter feeding a 3:1 VSWR will see 25 watts in the form of reflected power. This power is potentially lost as heat in the transmitter if nothing is done to correct the situation. If we install a tuner (in the shack), we can adjust it to provide a 50 ohm load to the transmitter (1:1 VSWR). But wait a second! A 1:1 VSWR implies the transmitter is not seeing any reflected power. So, where did it go? Did it get "cancelled" somewhere in the system? No. It got re-reflected back towards the antenna in phase with the incident power and radiated by the antenna. There's an easy way to prove this. Take a good quality directional wattmeter and install it between your transmitter and tuner to measure your forward power (100 W) and verify your reflected power at this point is zero. Move the wattmeter to the OTHER side of the tuner where the 3:1 VSWR exists. There you might see 125 watts of forward power and 25 watts of reflected power. But I only have a 100 watt transmitter! Where did the extra 25 watts come from? There is no extra power. What the wattmeter is showing is the vector product of the incident power from the transmitter (100 W) PLUS the reflected power the tuner has re-reflected back toward the load (25 W). Assuming a lossless tuner and transmission line, the total power radiated by the antenna will be 100 watts in this case, despite the 3:1 VSWR and 25% reflected power. These seemingly odd wattmeter readings make perfect sense when they are understood and interpreted correctly. 73, de John, KD2BD
Reply to a comment by : KD2BD on 2007-03-02

> Energy = Power * Time. This also implies that Power = Energy/Time We know from basic physics that Energy can neither be created nor destroyed. It can only converted from one form to another. So, then how can this statement: > the antenna emits less RF power when non resonant due > to cancellation of RF power. Thus the expected > transmitted power level is not produced. be true? The total RF power in the system is either going to be dissipated by the antenna as electromagnetic radiation, or dissipated as heat in dielectric or IR losses within the system. How, then, is RF power "cancelled" without time being modified or energy being destroyed? Anyone? 73, de John, KD2BD
Reply to a comment by : W4LGH on 2007-03-02

I said I wasn't going to post here anymore, but I did come across this article, that some of you should read. It talks about resonance, what it is and how and why it works. Pay attention to why a resonant antenna does what it does. 73 de W4LGH- Alan ====================================================== AN100 What SWR Does Not Show Written by Bill Ashley, EE for AEA Technology Inc. Abstract: This application note explains the advantage of measuring vector impedance vs. measuring SWR (network analyzer vs. SWR meter). Return loss and SWR express the same property (mismatch) using two different scales. All advantages and disadvantages of an SWR reading also apply to return loss readings. Introduction: The Standing Wave Ratio (SWR) of an antenna and its feedline has long been used to measure an antenna’s transmit efficiency. SWR is a simple concept, you send a unit of RF energy into the feedline, and measure the amount of energy that reflects back. We assume the portion of energy not reflected back transmits out the antenna. The limitations of this measurement usually cause the transmit efficiency to be lower than what SWR predicts. Using a network analyzer to measure vector impedance during antenna alignment improves transmitted efficiency compared to a simple SWR alignment. SWR meters have been around a long time, and many people are reluctant to change because SWR is an easy concept to understand. In the past, SWR meters were less expensive than vector impedance analyzers (aka network analyzers) which has been a determining factor in the SWR popularity. However, as costs in components continue to drop, the vector analyzers have become less expensive than they used to be. Since transmitters are rated in power, we will use the term “power”, not energy, for the remainder of this paper. These two quantities are closely related: Energy = Power * Time. SWR expresses impedance mismatch using the following formula: SWR = Z0/ZL or ZL/Z0 and Return Loss = 20*log(SWR) Use the SWR answer that equals or exceeds 1.0. Z0 is the characteristic impedance of the antenna/feedline, usually 50 ohms. ZL is the total impedance of the antenna/feedline. When SWR is 1.0 there is a perfect match, but this rarely occurs on a real antenna. Vector impedance separates the reactive and resistive components of the impedance. This separation allows the technician or engineer to “see” the impedance in a greater level of detail. Using vector impedance allows one to measure for both match and resonance. Discussion: The first question one might ask about the limitations of SWR: “If the power is not reflected back, where does it go?" The answer: the antenna emits less RF power when non resonant due to cancellation of RF power. Thus the expected transmitted power level is not produced. Vector impedance allows you to see resonant frequency during alignment (SWR doesn’t), so transmitted power can be improved. Now we ask “What is resonance, and how does it improve power”? Resonance in an antenna occurs when its impedance has no reactance, i.e. it is purely resistive. Reactance causes the voltage and current waveforms to shift out of phase with respect to each other (remember ELI the ICE man?). Since power equals voltage times current (P=V*I), the power factor drops below a perfect 1.0 when the V and I waveforms go out of phase and power cancellation occurs. Figure 1 shows an example of power cancellation due to a non resonant load. In this example, a capacitive load causes a 30 degree phase shift. The power produced is shown by the filled in areas, we see that a portion of the power produced went “negative” (blue area). This portion of the power curve is actually out of phase, and cancels out an equal portion (purple area) from the positive region. What is left over (yellow portion) is the actual power available for transmission. Figure 1. Power Cancellation Illustration With a purely reactive load, the power factor goes to 0. This happens because half the transmitted power cancels out the other half. Using a resonant antenna (power factor = 1.0) allows all of the transmitter’s RF power to radiate from the antenna. Table 1. Power Factor vs. Vector Impedance Angle Impedance Angle 0 15 30 45 60 75 90 Power Factor 1.000 0.965 0.866 0.707 0.500 0.259 0.000 The power factor shows the loss that occurs with a reactive load. Depending upon the design, a transmitter may generate even less power when connected to a reactive load. Reactive loads often cause an undesirable increase in the final tube or transistor power dissipation, resulting in degraded transmitter lifetime. Other limitations of SWR meters eliminated by network analyzers: 1. Designed for 50 ohm systems, SWR meters give misleading information for non 50 ohm antenna/feedlines. One case using a 30 ohm antenna had higher transmit efficiencies with the SWR of 1.6 (set resonant at 30 ohms) vs. when (de)tuned to an SWR of 1.2 (reactive load). Using vector impedance solved the “mystery”. 2. There is no method to remove feedline effects from SWR readings. Vector impedance analyzers usually have a cable null feature (open-short-load), so the antenna can be measured with cable effects removed. 3. Cannot produce a Smith Chart plot with SWR data. 4. Most SWR meters use wideband detectors, and are highly susceptible to interfering signals entering the antenna. Network analyzers usually involve some form of signal filtering and offer improved performance in such an environment. Conclusion: To align an antenna for the best efficiency, use vector impedance readings from a network analyzer; do not use an SWR meter or return loss reading.
Reply to a comment by : K9IUQ on 2007-03-02

K6IOU wrote: finally found the correct URL to an excellent article on Antennas and Feedlines . . . covers most of the stuff that has been 'discussed' here lately: http://members.dslextreme.com/users/w6wqc/antennas%20and%20feedlines.pdf .................................................... What a wonderful well written article. And references at the end - outstanding. No BS, just tells it like it is. I have seen everything in the article before in different places but it is very convenient to have it all in one place. This article is VERY readable, no hard to understand language. It should be REQUIRED reading for all hams especially for Newbies who have not seen these concepts before. Thanks for a great link Don. Stan K9IUQ
K9IUQ2007-03-02
Benchmarks
K6IOU SAYS I posted comments a few minutes ago and they never showed up here.
.......................................................
K9IUQ says a very good post Don here it is I received it.
.......................................................
Reposted for K6IOU

Has anyone on this forum wondered if maybe Al [W4LGH] really isn't as confused about all this as it appears? Maybe he is a classic internet 'troll'.

His apparent 'grasp' of all of this is so out-of-touch with reality that he really can't be taken seriously.

If he is, indeed, a troll . . . he has been very effective. This "Benchmarks" discussion has to set some kind of record as to length!

If he is 'for real' . . . it is sad indeed. Al, please read the current literature on all of this . . . specifically Maxwell's Reflections II and the ARRL Antenna Handbook. If what is contained in these two references can't convince you of your mis-guided thinking . . . certainly no one on this forum can either.

Al . . . how about this: open your copy of the ARRL Antenna Handbook, find a specific 'error' concerning antennas and feedlines . . . and report the Book Edition, page number, and the error to this group. I'd really like to have these errors uncovered and you would be doing a great service to amateur radio.

Regards,

DON
K6IOU
KD2BD2007-03-02
RE: Benchmarks
K9IUQ wrote:

> But if this is INDEED true then W4LGH's statement
> "The idea of an antenna tuner hooked to an
> un-balanced line (coax) is absurd." has to be FALSE?

Absolutely.

> You will change never W4LGH's *beliefs* but you have
> helped many of us here expand our knowledge.

Thank you, Stan. I'm glad it helped.

W4LGH wrote:

> And it wasn't talking about reflected power on the
> feed line, it was talking about reflected power on
> the antenna, since it was out of resonance and the
> actual sine wave reflected back will cancel the
> forward sine wave. But thats ok.

Stan, there's something about the term "Power Cancellation" that really bothers me. I don't see how power can be "cancelled", since energy cannot be created or destroyed, but I am open to ideas if anyone has any on the subject.

As far as reflected power on the ANTENNA is concerned, Al is starting to get really close to describing what resonance is really all about.

Recall the earlier statement in this thread that a resonant system possesses an impedance containing no net reactance.

That's true. But a Rhombic or Beverage antenna has a resistive feedpoint impedance as well, and they're anything BUT resonant antennas.

Could resonance have something to do with the concept of having reflected energy present on an antenna?

Yes!

If we could feed a dipole and watch what happens in slow motion, we might see an applied voltage produce a current flow along the right half of the dipole, and just the exact opposite in the left.

However, the current can only travel so far because the ends of the dipole are open. So, the current flows out to the end in one quarter of one RF cycle (90 degrees). In that period *SOME* RF is radiated by the antenna, but NOT ALL. The remaining energy that reaches the end can go no further, and so get REFLECTED BACK toward the direction of the feedpoint with no change in polarity.

As it travels back, a little more radiation takes place until it finally reaches the feedpoint where it is now 180 degrees out of phase (half wavelength delayed in time) with the RF sine wave that produced the initial current flow in the conductor.

A familiar standing wave pattern is produced on the dipole because of these phase relationships and the continued application of RF over time.

If none of the RF was radiated during the first RF half cycle described above, 100% would be reflected back from the end points to the feedpoint, giving the dipole an impedance of ZERO ohms.

(A dipole placed in a screened room would actually demonstrate this effect.)

If ALL of the RF was radiated during that first RF half cycle, and none reflected back to the feedpoint, the impedance of the dipole would be a VERY high number.

In real life, we know we're closer to the first scenario than the second.

The major implication in all this is that very little energy is radiated as RF flows along the conductors of the dipole. It takes many, many RF cycles (and many bounces of RF through the conductors of the dipole) for all the energy we apply to the dipole to be fully radiated into space over time.

That's what resonance is all about. It is a sustained oscillation of energy. The greater the amount of stored energy in the oscillations, the higher the system 'Q' (the lower the antenna's bandwidth).

Now, if the dipole is cut a little short or a little long, the energy reflected back from the dipole ends will arrive back at the feedpoint slightly out of phase with the next half cycle of the incident power, thereby producing a reactive feedpoint impedance.

If the antenna is too long, the reflected wave will arrive too late, producing a +J (inductive) (out-of-phase) reactive component. If it is too short, it will arrive too early, producing a -J (capacitive) (out-of-phase) reactive component.

These reactive components impede (NOT cancel) current flow into and out of the dipole, reducing the antenna's radiation efficiency.

We can adjust the length of the dipole to bring it into resonance, OR we can simply add the appropriate conjugate reactance into the feed system to compensate for this effect.

This can be done at the feedpoint, or even (shudder!) the shack with a tuner. :-) The type of feedline used doesn't enter into the equation.

Non-resonant antennas, such as the Beverage, don't produce standing wave patterns. They are "Travelling Wave" antennas, and behave much like lossy transmission lines.

The energy we apply to a Beverage travels down the antenna's conductor just once! Whatever doesn't get radiated on the initial trip ends up getting dissipated in the termination resistor. Nothing bounces back to the feedpoint. No standing waves are produced, and the impedance of the Beverage becomes essentially equal to that of the terminating resistor.

Since the RF travels only once down a Beverage, and as we pointed out earlier, very little RF is radiated along a conductor in one trip, the Beverage has to be VERY long in terms of wavelength in order to be comparable in efficiency to a much shorter standing wave antenna (dipole).

Stan, those are the properties I would use to describe and define resonance (or lack thereof) in an antenna system.

I hope it makes some sense.


73, de John, KD2BD
Reply to a comment by : KD2BD on 2007-03-02

W4LGH wrote: > Signals can be canceled by a phase shift. if you > signals that are equal are 180 degs out of phase they > will cancel, null each other out. I can apply 10 mA of DC current through a resistor in one direction, and apply 10 mA of DC current through the resistor in the other direction, and the net current flow through the resistor will be 0 mA. Yes. I agree. But POWER isn't "cancelled" in the process. Current simply isn't being drawn from the voltage sources. > If you look at the wave forms on your ramdon wire, > the reflected signal can be less <= the forward > signal. Any amount of reflected signal, lets say for > example 10% will subtract from the main signal. Only if nothing is done to re-reflect that energy BACK towards the antenna again. The device that does this is the antenna tuner. A 100-watt transmitter feeding a 3:1 VSWR will see 25 watts in the form of reflected power. This power is potentially lost as heat in the transmitter if nothing is done to correct the situation. If we install a tuner (in the shack), we can adjust it to provide a 50 ohm load to the transmitter (1:1 VSWR). But wait a second! A 1:1 VSWR implies the transmitter is not seeing any reflected power. So, where did it go? Did it get "cancelled" somewhere in the system? No. It got re-reflected back towards the antenna in phase with the incident power and radiated by the antenna. There's an easy way to prove this. Take a good quality directional wattmeter and install it between your transmitter and tuner to measure your forward power (100 W) and verify your reflected power at this point is zero. Move the wattmeter to the OTHER side of the tuner where the 3:1 VSWR exists. There you might see 125 watts of forward power and 25 watts of reflected power. But I only have a 100 watt transmitter! Where did the extra 25 watts come from? There is no extra power. What the wattmeter is showing is the vector product of the incident power from the transmitter (100 W) PLUS the reflected power the tuner has re-reflected back toward the load (25 W). Assuming a lossless tuner and transmission line, the total power radiated by the antenna will be 100 watts in this case, despite the 3:1 VSWR and 25% reflected power. These seemingly odd wattmeter readings make perfect sense when they are understood and interpreted correctly. 73, de John, KD2BD
Reply to a comment by : KD2BD on 2007-03-02

> Energy = Power * Time. This also implies that Power = Energy/Time We know from basic physics that Energy can neither be created nor destroyed. It can only converted from one form to another. So, then how can this statement: > the antenna emits less RF power when non resonant due > to cancellation of RF power. Thus the expected > transmitted power level is not produced. be true? The total RF power in the system is either going to be dissipated by the antenna as electromagnetic radiation, or dissipated as heat in dielectric or IR losses within the system. How, then, is RF power "cancelled" without time being modified or energy being destroyed? Anyone? 73, de John, KD2BD
Reply to a comment by : W4LGH on 2007-03-02

I said I wasn't going to post here anymore, but I did come across this article, that some of you should read. It talks about resonance, what it is and how and why it works. Pay attention to why a resonant antenna does what it does. 73 de W4LGH- Alan ====================================================== AN100 What SWR Does Not Show Written by Bill Ashley, EE for AEA Technology Inc. Abstract: This application note explains the advantage of measuring vector impedance vs. measuring SWR (network analyzer vs. SWR meter). Return loss and SWR express the same property (mismatch) using two different scales. All advantages and disadvantages of an SWR reading also apply to return loss readings. Introduction: The Standing Wave Ratio (SWR) of an antenna and its feedline has long been used to measure an antenna’s transmit efficiency. SWR is a simple concept, you send a unit of RF energy into the feedline, and measure the amount of energy that reflects back. We assume the portion of energy not reflected back transmits out the antenna. The limitations of this measurement usually cause the transmit efficiency to be lower than what SWR predicts. Using a network analyzer to measure vector impedance during antenna alignment improves transmitted efficiency compared to a simple SWR alignment. SWR meters have been around a long time, and many people are reluctant to change because SWR is an easy concept to understand. In the past, SWR meters were less expensive than vector impedance analyzers (aka network analyzers) which has been a determining factor in the SWR popularity. However, as costs in components continue to drop, the vector analyzers have become less expensive than they used to be. Since transmitters are rated in power, we will use the term “power”, not energy, for the remainder of this paper. These two quantities are closely related: Energy = Power * Time. SWR expresses impedance mismatch using the following formula: SWR = Z0/ZL or ZL/Z0 and Return Loss = 20*log(SWR) Use the SWR answer that equals or exceeds 1.0. Z0 is the characteristic impedance of the antenna/feedline, usually 50 ohms. ZL is the total impedance of the antenna/feedline. When SWR is 1.0 there is a perfect match, but this rarely occurs on a real antenna. Vector impedance separates the reactive and resistive components of the impedance. This separation allows the technician or engineer to “see” the impedance in a greater level of detail. Using vector impedance allows one to measure for both match and resonance. Discussion: The first question one might ask about the limitations of SWR: “If the power is not reflected back, where does it go?" The answer: the antenna emits less RF power when non resonant due to cancellation of RF power. Thus the expected transmitted power level is not produced. Vector impedance allows you to see resonant frequency during alignment (SWR doesn’t), so transmitted power can be improved. Now we ask “What is resonance, and how does it improve power”? Resonance in an antenna occurs when its impedance has no reactance, i.e. it is purely resistive. Reactance causes the voltage and current waveforms to shift out of phase with respect to each other (remember ELI the ICE man?). Since power equals voltage times current (P=V*I), the power factor drops below a perfect 1.0 when the V and I waveforms go out of phase and power cancellation occurs. Figure 1 shows an example of power cancellation due to a non resonant load. In this example, a capacitive load causes a 30 degree phase shift. The power produced is shown by the filled in areas, we see that a portion of the power produced went “negative” (blue area). This portion of the power curve is actually out of phase, and cancels out an equal portion (purple area) from the positive region. What is left over (yellow portion) is the actual power available for transmission. Figure 1. Power Cancellation Illustration With a purely reactive load, the power factor goes to 0. This happens because half the transmitted power cancels out the other half. Using a resonant antenna (power factor = 1.0) allows all of the transmitter’s RF power to radiate from the antenna. Table 1. Power Factor vs. Vector Impedance Angle Impedance Angle 0 15 30 45 60 75 90 Power Factor 1.000 0.965 0.866 0.707 0.500 0.259 0.000 The power factor shows the loss that occurs with a reactive load. Depending upon the design, a transmitter may generate even less power when connected to a reactive load. Reactive loads often cause an undesirable increase in the final tube or transistor power dissipation, resulting in degraded transmitter lifetime. Other limitations of SWR meters eliminated by network analyzers: 1. Designed for 50 ohm systems, SWR meters give misleading information for non 50 ohm antenna/feedlines. One case using a 30 ohm antenna had higher transmit efficiencies with the SWR of 1.6 (set resonant at 30 ohms) vs. when (de)tuned to an SWR of 1.2 (reactive load). Using vector impedance solved the “mystery”. 2. There is no method to remove feedline effects from SWR readings. Vector impedance analyzers usually have a cable null feature (open-short-load), so the antenna can be measured with cable effects removed. 3. Cannot produce a Smith Chart plot with SWR data. 4. Most SWR meters use wideband detectors, and are highly susceptible to interfering signals entering the antenna. Network analyzers usually involve some form of signal filtering and offer improved performance in such an environment. Conclusion: To align an antenna for the best efficiency, use vector impedance readings from a network analyzer; do not use an SWR meter or return loss reading.
Reply to a comment by : K9IUQ on 2007-03-02

K6IOU wrote: finally found the correct URL to an excellent article on Antennas and Feedlines . . . covers most of the stuff that has been 'discussed' here lately: http://members.dslextreme.com/users/w6wqc/antennas%20and%20feedlines.pdf .................................................... What a wonderful well written article. And references at the end - outstanding. No BS, just tells it like it is. I have seen everything in the article before in different places but it is very convenient to have it all in one place. This article is VERY readable, no hard to understand language. It should be REQUIRED reading for all hams especially for Newbies who have not seen these concepts before. Thanks for a great link Don. Stan K9IUQ
K9IUQ2007-03-02
Benchmarks
W4LGH wrote: Must not come back to thread anymore,

DONE, OVER AND OUT!

This will be my LAST response to you Stanley.

I said I wasn't going to post here anymore

de W4LGH OUT/QRT on eHam

You see, you just don't get it.

Nawwwwww...we wouldn't be that lucky!
.......................................................
KD2BD says "Sorry. None of that is true. Not even close."


K9IUQ SAYS , Leave Al, you been saying that for 3 days. But you cant leave. You *need* to have the last word.


Stan K9IUQ



K6IOU2007-03-02
RE: Benchmarks
I posted comments a few minutes ago and they never showed up here.

Once again, "Cutting to the chase" as they say:

AL . . . most of us here have a copy of the ARRL Antenna Handbook. You would do amateur radio a big service if you would open your copy, find an error or two concerning antennas and feedlines, and then report back to this group the Handbook edition you have, the page number containing the error, and the error itself.

Let us know "how it should read"!

Thanks in advance,

DON
K6IOU
Reply to a comment by : W4LGH on 2007-03-02

John...there simply is no hope for you, I believe you are going to argue when your time is up and they come to get you. Something about reflected years were added back to your total # of years allowed. I have done the experiment you siad, and have NEVER seen additional power on the meter, only the reflected power. And it wasn't talking about reflected power on the feed line, it was talking about reflected power on the antenna, since it was out of resonance and the actual sine wave reflected back will cancel the forward sine wave. But thats ok. I am thru arguing about this, you believe what you want, as they say if you TRUELY believe then it must be so. Have a nice day!
Reply to a comment by : KD2BD on 2007-03-02

W4LGH wrote: > Signals can be canceled by a phase shift. if you > signals that are equal are 180 degs out of phase they > will cancel, null each other out. I can apply 10 mA of DC current through a resistor in one direction, and apply 10 mA of DC current through the resistor in the other direction, and the net current flow through the resistor will be 0 mA. Yes. I agree. But POWER isn't "cancelled" in the process. Current simply isn't being drawn from the voltage sources. > If you look at the wave forms on your ramdon wire, > the reflected signal can be less <= the forward > signal. Any amount of reflected signal, lets say for > example 10% will subtract from the main signal. Only if nothing is done to re-reflect that energy BACK towards the antenna again. The device that does this is the antenna tuner. A 100-watt transmitter feeding a 3:1 VSWR will see 25 watts in the form of reflected power. This power is potentially lost as heat in the transmitter if nothing is done to correct the situation. If we install a tuner (in the shack), we can adjust it to provide a 50 ohm load to the transmitter (1:1 VSWR). But wait a second! A 1:1 VSWR implies the transmitter is not seeing any reflected power. So, where did it go? Did it get "cancelled" somewhere in the system? No. It got re-reflected back towards the antenna in phase with the incident power and radiated by the antenna. There's an easy way to prove this. Take a good quality directional wattmeter and install it between your transmitter and tuner to measure your forward power (100 W) and verify your reflected power at this point is zero. Move the wattmeter to the OTHER side of the tuner where the 3:1 VSWR exists. There you might see 125 watts of forward power and 25 watts of reflected power. But I only have a 100 watt transmitter! Where did the extra 25 watts come from? There is no extra power. What the wattmeter is showing is the vector product of the incident power from the transmitter (100 W) PLUS the reflected power the tuner has re-reflected back toward the load (25 W). Assuming a lossless tuner and transmission line, the total power radiated by the antenna will be 100 watts in this case, despite the 3:1 VSWR and 25% reflected power. These seemingly odd wattmeter readings make perfect sense when they are understood and interpreted correctly. 73, de John, KD2BD
Reply to a comment by : KD2BD on 2007-03-02

> Energy = Power * Time. This also implies that Power = Energy/Time We know from basic physics that Energy can neither be created nor destroyed. It can only converted from one form to another. So, then how can this statement: > the antenna emits less RF power when non resonant due > to cancellation of RF power. Thus the expected > transmitted power level is not produced. be true? The total RF power in the system is either going to be dissipated by the antenna as electromagnetic radiation, or dissipated as heat in dielectric or IR losses within the system. How, then, is RF power "cancelled" without time being modified or energy being destroyed? Anyone? 73, de John, KD2BD
Reply to a comment by : W4LGH on 2007-03-02

I said I wasn't going to post here anymore, but I did come across this article, that some of you should read. It talks about resonance, what it is and how and why it works. Pay attention to why a resonant antenna does what it does. 73 de W4LGH- Alan ====================================================== AN100 What SWR Does Not Show Written by Bill Ashley, EE for AEA Technology Inc. Abstract: This application note explains the advantage of measuring vector impedance vs. measuring SWR (network analyzer vs. SWR meter). Return loss and SWR express the same property (mismatch) using two different scales. All advantages and disadvantages of an SWR reading also apply to return loss readings. Introduction: The Standing Wave Ratio (SWR) of an antenna and its feedline has long been used to measure an antenna’s transmit efficiency. SWR is a simple concept, you send a unit of RF energy into the feedline, and measure the amount of energy that reflects back. We assume the portion of energy not reflected back transmits out the antenna. The limitations of this measurement usually cause the transmit efficiency to be lower than what SWR predicts. Using a network analyzer to measure vector impedance during antenna alignment improves transmitted efficiency compared to a simple SWR alignment. SWR meters have been around a long time, and many people are reluctant to change because SWR is an easy concept to understand. In the past, SWR meters were less expensive than vector impedance analyzers (aka network analyzers) which has been a determining factor in the SWR popularity. However, as costs in components continue to drop, the vector analyzers have become less expensive than they used to be. Since transmitters are rated in power, we will use the term “power”, not energy, for the remainder of this paper. These two quantities are closely related: Energy = Power * Time. SWR expresses impedance mismatch using the following formula: SWR = Z0/ZL or ZL/Z0 and Return Loss = 20*log(SWR) Use the SWR answer that equals or exceeds 1.0. Z0 is the characteristic impedance of the antenna/feedline, usually 50 ohms. ZL is the total impedance of the antenna/feedline. When SWR is 1.0 there is a perfect match, but this rarely occurs on a real antenna. Vector impedance separates the reactive and resistive components of the impedance. This separation allows the technician or engineer to “see” the impedance in a greater level of detail. Using vector impedance allows one to measure for both match and resonance. Discussion: The first question one might ask about the limitations of SWR: “If the power is not reflected back, where does it go?" The answer: the antenna emits less RF power when non resonant due to cancellation of RF power. Thus the expected transmitted power level is not produced. Vector impedance allows you to see resonant frequency during alignment (SWR doesn’t), so transmitted power can be improved. Now we ask “What is resonance, and how does it improve power”? Resonance in an antenna occurs when its impedance has no reactance, i.e. it is purely resistive. Reactance causes the voltage and current waveforms to shift out of phase with respect to each other (remember ELI the ICE man?). Since power equals voltage times current (P=V*I), the power factor drops below a perfect 1.0 when the V and I waveforms go out of phase and power cancellation occurs. Figure 1 shows an example of power cancellation due to a non resonant load. In this example, a capacitive load causes a 30 degree phase shift. The power produced is shown by the filled in areas, we see that a portion of the power produced went “negative” (blue area). This portion of the power curve is actually out of phase, and cancels out an equal portion (purple area) from the positive region. What is left over (yellow portion) is the actual power available for transmission. Figure 1. Power Cancellation Illustration With a purely reactive load, the power factor goes to 0. This happens because half the transmitted power cancels out the other half. Using a resonant antenna (power factor = 1.0) allows all of the transmitter’s RF power to radiate from the antenna. Table 1. Power Factor vs. Vector Impedance Angle Impedance Angle 0 15 30 45 60 75 90 Power Factor 1.000 0.965 0.866 0.707 0.500 0.259 0.000 The power factor shows the loss that occurs with a reactive load. Depending upon the design, a transmitter may generate even less power when connected to a reactive load. Reactive loads often cause an undesirable increase in the final tube or transistor power dissipation, resulting in degraded transmitter lifetime. Other limitations of SWR meters eliminated by network analyzers: 1. Designed for 50 ohm systems, SWR meters give misleading information for non 50 ohm antenna/feedlines. One case using a 30 ohm antenna had higher transmit efficiencies with the SWR of 1.6 (set resonant at 30 ohms) vs. when (de)tuned to an SWR of 1.2 (reactive load). Using vector impedance solved the “mystery”. 2. There is no method to remove feedline effects from SWR readings. Vector impedance analyzers usually have a cable null feature (open-short-load), so the antenna can be measured with cable effects removed. 3. Cannot produce a Smith Chart plot with SWR data. 4. Most SWR meters use wideband detectors, and are highly susceptible to interfering signals entering the antenna. Network analyzers usually involve some form of signal filtering and offer improved performance in such an environment. Conclusion: To align an antenna for the best efficiency, use vector impedance readings from a network analyzer; do not use an SWR meter or return loss reading.
Reply to a comment by : K9IUQ on 2007-03-02

K6IOU wrote: finally found the correct URL to an excellent article on Antennas and Feedlines . . . covers most of the stuff that has been 'discussed' here lately: http://members.dslextreme.com/users/w6wqc/antennas%20and%20feedlines.pdf .................................................... What a wonderful well written article. And references at the end - outstanding. No BS, just tells it like it is. I have seen everything in the article before in different places but it is very convenient to have it all in one place. This article is VERY readable, no hard to understand language. It should be REQUIRED reading for all hams especially for Newbies who have not seen these concepts before. Thanks for a great link Don. Stan K9IUQ
W4LGH2007-03-02
RE: Benchmarks
I am going to make an exception for you too Stan...
Here is the deal....
1:If hooking an antenna tuner to the back of your radio, or using the tuner built into your radio, and you think you are tuning the "antenna" NOT the "antenna system" into resonance, thats ABSURD.
2: If you think your inside antenna tuner changes the radiated sine wave and stops the cancelation on the "antenna" and not the "antenna system" thats ABSURD.
3: If you understand that your internal antenna is only matching the impedance between you coax and you radio, and you will accept the loss, in the coax, and on the "antenna" and the total loss on the "antenna system" then OK.
4:If you are feeding your antenna with open feeder line to your inside tuner, and you understand that in the past to POSTED articles where it say that balanced line DOES radiate, as it is hardle ever in balance due to natural outside causes, so you are tuning this into your "antenna system" then OK.

Thats it...NO you will NOT change my knowledge on this, there is a lot to be learned here if one will open their minds, do a little studying on resonance, and how sine waves react 2 resonance and how they react out of resonance @ the "ANTENNA" forget feed lines an dwhat happening there, that is totally after the fact. And if you believe you can start off with a 100w transmiter, and have a 3:1 SWR, and read 125watts on the antenna side...I hav eheard it all now! We only started off with 100, everything passive has a loss, geee we would only need 10watt transmitters and HIGH SWR antennas to get more power out. Yes sir, that price on that ocean front property is steadly going up...

There is NO HOPE...Must not come back to thread anymore, its enough to drive me to drinking!

Do it your way , run your passive devices that multiply your power and work everyone you hear!

73 es Best of DX..
de W4LGH - Alan
http://ww.w4lgh.com

Reply to a comment by : W4LGH on 2007-03-02

John...there simply is no hope for you, I believe you are going to argue when your time is up and they come to get you. Something about reflected years were added back to your total # of years allowed. I have done the experiment you siad, and have NEVER seen additional power on the meter, only the reflected power. And it wasn't talking about reflected power on the feed line, it was talking about reflected power on the antenna, since it was out of resonance and the actual sine wave reflected back will cancel the forward sine wave. But thats ok. I am thru arguing about this, you believe what you want, as they say if you TRUELY believe then it must be so. Have a nice day!
Reply to a comment by : KD2BD on 2007-03-02

W4LGH wrote: > Signals can be canceled by a phase shift. if you > signals that are equal are 180 degs out of phase they > will cancel, null each other out. I can apply 10 mA of DC current through a resistor in one direction, and apply 10 mA of DC current through the resistor in the other direction, and the net current flow through the resistor will be 0 mA. Yes. I agree. But POWER isn't "cancelled" in the process. Current simply isn't being drawn from the voltage sources. > If you look at the wave forms on your ramdon wire, > the reflected signal can be less <= the forward > signal. Any amount of reflected signal, lets say for > example 10% will subtract from the main signal. Only if nothing is done to re-reflect that energy BACK towards the antenna again. The device that does this is the antenna tuner. A 100-watt transmitter feeding a 3:1 VSWR will see 25 watts in the form of reflected power. This power is potentially lost as heat in the transmitter if nothing is done to correct the situation. If we install a tuner (in the shack), we can adjust it to provide a 50 ohm load to the transmitter (1:1 VSWR). But wait a second! A 1:1 VSWR implies the transmitter is not seeing any reflected power. So, where did it go? Did it get "cancelled" somewhere in the system? No. It got re-reflected back towards the antenna in phase with the incident power and radiated by the antenna. There's an easy way to prove this. Take a good quality directional wattmeter and install it between your transmitter and tuner to measure your forward power (100 W) and verify your reflected power at this point is zero. Move the wattmeter to the OTHER side of the tuner where the 3:1 VSWR exists. There you might see 125 watts of forward power and 25 watts of reflected power. But I only have a 100 watt transmitter! Where did the extra 25 watts come from? There is no extra power. What the wattmeter is showing is the vector product of the incident power from the transmitter (100 W) PLUS the reflected power the tuner has re-reflected back toward the load (25 W). Assuming a lossless tuner and transmission line, the total power radiated by the antenna will be 100 watts in this case, despite the 3:1 VSWR and 25% reflected power. These seemingly odd wattmeter readings make perfect sense when they are understood and interpreted correctly. 73, de John, KD2BD
Reply to a comment by : KD2BD on 2007-03-02

> Energy = Power * Time. This also implies that Power = Energy/Time We know from basic physics that Energy can neither be created nor destroyed. It can only converted from one form to another. So, then how can this statement: > the antenna emits less RF power when non resonant due > to cancellation of RF power. Thus the expected > transmitted power level is not produced. be true? The total RF power in the system is either going to be dissipated by the antenna as electromagnetic radiation, or dissipated as heat in dielectric or IR losses within the system. How, then, is RF power "cancelled" without time being modified or energy being destroyed? Anyone? 73, de John, KD2BD
Reply to a comment by : W4LGH on 2007-03-02

I said I wasn't going to post here anymore, but I did come across this article, that some of you should read. It talks about resonance, what it is and how and why it works. Pay attention to why a resonant antenna does what it does. 73 de W4LGH- Alan ====================================================== AN100 What SWR Does Not Show Written by Bill Ashley, EE for AEA Technology Inc. Abstract: This application note explains the advantage of measuring vector impedance vs. measuring SWR (network analyzer vs. SWR meter). Return loss and SWR express the same property (mismatch) using two different scales. All advantages and disadvantages of an SWR reading also apply to return loss readings. Introduction: The Standing Wave Ratio (SWR) of an antenna and its feedline has long been used to measure an antenna’s transmit efficiency. SWR is a simple concept, you send a unit of RF energy into the feedline, and measure the amount of energy that reflects back. We assume the portion of energy not reflected back transmits out the antenna. The limitations of this measurement usually cause the transmit efficiency to be lower than what SWR predicts. Using a network analyzer to measure vector impedance during antenna alignment improves transmitted efficiency compared to a simple SWR alignment. SWR meters have been around a long time, and many people are reluctant to change because SWR is an easy concept to understand. In the past, SWR meters were less expensive than vector impedance analyzers (aka network analyzers) which has been a determining factor in the SWR popularity. However, as costs in components continue to drop, the vector analyzers have become less expensive than they used to be. Since transmitters are rated in power, we will use the term “power”, not energy, for the remainder of this paper. These two quantities are closely related: Energy = Power * Time. SWR expresses impedance mismatch using the following formula: SWR = Z0/ZL or ZL/Z0 and Return Loss = 20*log(SWR) Use the SWR answer that equals or exceeds 1.0. Z0 is the characteristic impedance of the antenna/feedline, usually 50 ohms. ZL is the total impedance of the antenna/feedline. When SWR is 1.0 there is a perfect match, but this rarely occurs on a real antenna. Vector impedance separates the reactive and resistive components of the impedance. This separation allows the technician or engineer to “see” the impedance in a greater level of detail. Using vector impedance allows one to measure for both match and resonance. Discussion: The first question one might ask about the limitations of SWR: “If the power is not reflected back, where does it go?" The answer: the antenna emits less RF power when non resonant due to cancellation of RF power. Thus the expected transmitted power level is not produced. Vector impedance allows you to see resonant frequency during alignment (SWR doesn’t), so transmitted power can be improved. Now we ask “What is resonance, and how does it improve power”? Resonance in an antenna occurs when its impedance has no reactance, i.e. it is purely resistive. Reactance causes the voltage and current waveforms to shift out of phase with respect to each other (remember ELI the ICE man?). Since power equals voltage times current (P=V*I), the power factor drops below a perfect 1.0 when the V and I waveforms go out of phase and power cancellation occurs. Figure 1 shows an example of power cancellation due to a non resonant load. In this example, a capacitive load causes a 30 degree phase shift. The power produced is shown by the filled in areas, we see that a portion of the power produced went “negative” (blue area). This portion of the power curve is actually out of phase, and cancels out an equal portion (purple area) from the positive region. What is left over (yellow portion) is the actual power available for transmission. Figure 1. Power Cancellation Illustration With a purely reactive load, the power factor goes to 0. This happens because half the transmitted power cancels out the other half. Using a resonant antenna (power factor = 1.0) allows all of the transmitter’s RF power to radiate from the antenna. Table 1. Power Factor vs. Vector Impedance Angle Impedance Angle 0 15 30 45 60 75 90 Power Factor 1.000 0.965 0.866 0.707 0.500 0.259 0.000 The power factor shows the loss that occurs with a reactive load. Depending upon the design, a transmitter may generate even less power when connected to a reactive load. Reactive loads often cause an undesirable increase in the final tube or transistor power dissipation, resulting in degraded transmitter lifetime. Other limitations of SWR meters eliminated by network analyzers: 1. Designed for 50 ohm systems, SWR meters give misleading information for non 50 ohm antenna/feedlines. One case using a 30 ohm antenna had higher transmit efficiencies with the SWR of 1.6 (set resonant at 30 ohms) vs. when (de)tuned to an SWR of 1.2 (reactive load). Using vector impedance solved the “mystery”. 2. There is no method to remove feedline effects from SWR readings. Vector impedance analyzers usually have a cable null feature (open-short-load), so the antenna can be measured with cable effects removed. 3. Cannot produce a Smith Chart plot with SWR data. 4. Most SWR meters use wideband detectors, and are highly susceptible to interfering signals entering the antenna. Network analyzers usually involve some form of signal filtering and offer improved performance in such an environment. Conclusion: To align an antenna for the best efficiency, use vector impedance readings from a network analyzer; do not use an SWR meter or return loss reading.
Reply to a comment by : K9IUQ on 2007-03-02

K6IOU wrote: finally found the correct URL to an excellent article on Antennas and Feedlines . . . covers most of the stuff that has been 'discussed' here lately: http://members.dslextreme.com/users/w6wqc/antennas%20and%20feedlines.pdf .................................................... What a wonderful well written article. And references at the end - outstanding. No BS, just tells it like it is. I have seen everything in the article before in different places but it is very convenient to have it all in one place. This article is VERY readable, no hard to understand language. It should be REQUIRED reading for all hams especially for Newbies who have not seen these concepts before. Thanks for a great link Don. Stan K9IUQ
K6IOU2007-03-02
RE: Benchmarks
Has anyone on this forum wondered if maybe Al [W4LGH] really isn't as confused about all this as it appears? Maybe he is a classic internet 'troll'.

His apparent 'grasp' of all of this is so out-of-touch with reality that he really can't be taken seriously.

If he is, indeed, a troll . . . he has been very effective. This "Benchmarks" discussion has to set some kind of record as to length!

If he is 'for real' . . . it is sad indeed. Al, please read the current literature on all of this . . . specifically Maxwell's Reflections II and the ARRL Antenna Handbook. If what is contained in these two references can't convince you of your mis-guided thinking . . . certainly no one on this forum can either.

Al . . . how about this: open your copy of the ARRL Antenna Handbook, find a specific 'error' concerning antennas and feedlines . . . and report the Book Edition, page number, and the error to this group. I'd really like to have these errors uncovered and you would be doing a great service to amateur radio.

Regards,

DON
K6IOU
Reply to a comment by : W4LGH on 2007-03-02

John...there simply is no hope for you, I believe you are going to argue when your time is up and they come to get you. Something about reflected years were added back to your total # of years allowed. I have done the experiment you siad, and have NEVER seen additional power on the meter, only the reflected power. And it wasn't talking about reflected power on the feed line, it was talking about reflected power on the antenna, since it was out of resonance and the actual sine wave reflected back will cancel the forward sine wave. But thats ok. I am thru arguing about this, you believe what you want, as they say if you TRUELY believe then it must be so. Have a nice day!
Reply to a comment by : KD2BD on 2007-03-02

W4LGH wrote: > Signals can be canceled by a phase shift. if you > signals that are equal are 180 degs out of phase they > will cancel, null each other out. I can apply 10 mA of DC current through a resistor in one direction, and apply 10 mA of DC current through the resistor in the other direction, and the net current flow through the resistor will be 0 mA. Yes. I agree. But POWER isn't "cancelled" in the process. Current simply isn't being drawn from the voltage sources. > If you look at the wave forms on your ramdon wire, > the reflected signal can be less <= the forward > signal. Any amount of reflected signal, lets say for > example 10% will subtract from the main signal. Only if nothing is done to re-reflect that energy BACK towards the antenna again. The device that does this is the antenna tuner. A 100-watt transmitter feeding a 3:1 VSWR will see 25 watts in the form of reflected power. This power is potentially lost as heat in the transmitter if nothing is done to correct the situation. If we install a tuner (in the shack), we can adjust it to provide a 50 ohm load to the transmitter (1:1 VSWR). But wait a second! A 1:1 VSWR implies the transmitter is not seeing any reflected power. So, where did it go? Did it get "cancelled" somewhere in the system? No. It got re-reflected back towards the antenna in phase with the incident power and radiated by the antenna. There's an easy way to prove this. Take a good quality directional wattmeter and install it between your transmitter and tuner to measure your forward power (100 W) and verify your reflected power at this point is zero. Move the wattmeter to the OTHER side of the tuner where the 3:1 VSWR exists. There you might see 125 watts of forward power and 25 watts of reflected power. But I only have a 100 watt transmitter! Where did the extra 25 watts come from? There is no extra power. What the wattmeter is showing is the vector product of the incident power from the transmitter (100 W) PLUS the reflected power the tuner has re-reflected back toward the load (25 W). Assuming a lossless tuner and transmission line, the total power radiated by the antenna will be 100 watts in this case, despite the 3:1 VSWR and 25% reflected power. These seemingly odd wattmeter readings make perfect sense when they are understood and interpreted correctly. 73, de John, KD2BD
Reply to a comment by : KD2BD on 2007-03-02

> Energy = Power * Time. This also implies that Power = Energy/Time We know from basic physics that Energy can neither be created nor destroyed. It can only converted from one form to another. So, then how can this statement: > the antenna emits less RF power when non resonant due > to cancellation of RF power. Thus the expected > transmitted power level is not produced. be true? The total RF power in the system is either going to be dissipated by the antenna as electromagnetic radiation, or dissipated as heat in dielectric or IR losses within the system. How, then, is RF power "cancelled" without time being modified or energy being destroyed? Anyone? 73, de John, KD2BD
Reply to a comment by : W4LGH on 2007-03-02

I said I wasn't going to post here anymore, but I did come across this article, that some of you should read. It talks about resonance, what it is and how and why it works. Pay attention to why a resonant antenna does what it does. 73 de W4LGH- Alan ====================================================== AN100 What SWR Does Not Show Written by Bill Ashley, EE for AEA Technology Inc. Abstract: This application note explains the advantage of measuring vector impedance vs. measuring SWR (network analyzer vs. SWR meter). Return loss and SWR express the same property (mismatch) using two different scales. All advantages and disadvantages of an SWR reading also apply to return loss readings. Introduction: The Standing Wave Ratio (SWR) of an antenna and its feedline has long been used to measure an antenna’s transmit efficiency. SWR is a simple concept, you send a unit of RF energy into the feedline, and measure the amount of energy that reflects back. We assume the portion of energy not reflected back transmits out the antenna. The limitations of this measurement usually cause the transmit efficiency to be lower than what SWR predicts. Using a network analyzer to measure vector impedance during antenna alignment improves transmitted efficiency compared to a simple SWR alignment. SWR meters have been around a long time, and many people are reluctant to change because SWR is an easy concept to understand. In the past, SWR meters were less expensive than vector impedance analyzers (aka network analyzers) which has been a determining factor in the SWR popularity. However, as costs in components continue to drop, the vector analyzers have become less expensive than they used to be. Since transmitters are rated in power, we will use the term “power”, not energy, for the remainder of this paper. These two quantities are closely related: Energy = Power * Time. SWR expresses impedance mismatch using the following formula: SWR = Z0/ZL or ZL/Z0 and Return Loss = 20*log(SWR) Use the SWR answer that equals or exceeds 1.0. Z0 is the characteristic impedance of the antenna/feedline, usually 50 ohms. ZL is the total impedance of the antenna/feedline. When SWR is 1.0 there is a perfect match, but this rarely occurs on a real antenna. Vector impedance separates the reactive and resistive components of the impedance. This separation allows the technician or engineer to “see” the impedance in a greater level of detail. Using vector impedance allows one to measure for both match and resonance. Discussion: The first question one might ask about the limitations of SWR: “If the power is not reflected back, where does it go?" The answer: the antenna emits less RF power when non resonant due to cancellation of RF power. Thus the expected transmitted power level is not produced. Vector impedance allows you to see resonant frequency during alignment (SWR doesn’t), so transmitted power can be improved. Now we ask “What is resonance, and how does it improve power”? Resonance in an antenna occurs when its impedance has no reactance, i.e. it is purely resistive. Reactance causes the voltage and current waveforms to shift out of phase with respect to each other (remember ELI the ICE man?). Since power equals voltage times current (P=V*I), the power factor drops below a perfect 1.0 when the V and I waveforms go out of phase and power cancellation occurs. Figure 1 shows an example of power cancellation due to a non resonant load. In this example, a capacitive load causes a 30 degree phase shift. The power produced is shown by the filled in areas, we see that a portion of the power produced went “negative” (blue area). This portion of the power curve is actually out of phase, and cancels out an equal portion (purple area) from the positive region. What is left over (yellow portion) is the actual power available for transmission. Figure 1. Power Cancellation Illustration With a purely reactive load, the power factor goes to 0. This happens because half the transmitted power cancels out the other half. Using a resonant antenna (power factor = 1.0) allows all of the transmitter’s RF power to radiate from the antenna. Table 1. Power Factor vs. Vector Impedance Angle Impedance Angle 0 15 30 45 60 75 90 Power Factor 1.000 0.965 0.866 0.707 0.500 0.259 0.000 The power factor shows the loss that occurs with a reactive load. Depending upon the design, a transmitter may generate even less power when connected to a reactive load. Reactive loads often cause an undesirable increase in the final tube or transistor power dissipation, resulting in degraded transmitter lifetime. Other limitations of SWR meters eliminated by network analyzers: 1. Designed for 50 ohm systems, SWR meters give misleading information for non 50 ohm antenna/feedlines. One case using a 30 ohm antenna had higher transmit efficiencies with the SWR of 1.6 (set resonant at 30 ohms) vs. when (de)tuned to an SWR of 1.2 (reactive load). Using vector impedance solved the “mystery”. 2. There is no method to remove feedline effects from SWR readings. Vector impedance analyzers usually have a cable null feature (open-short-load), so the antenna can be measured with cable effects removed. 3. Cannot produce a Smith Chart plot with SWR data. 4. Most SWR meters use wideband detectors, and are highly susceptible to interfering signals entering the antenna. Network analyzers usually involve some form of signal filtering and offer improved performance in such an environment. Conclusion: To align an antenna for the best efficiency, use vector impedance readings from a network analyzer; do not use an SWR meter or return loss reading.
Reply to a comment by : K9IUQ on 2007-03-02

K6IOU wrote: finally found the correct URL to an excellent article on Antennas and Feedlines . . . covers most of the stuff that has been 'discussed' here lately: http://members.dslextreme.com/users/w6wqc/antennas%20and%20feedlines.pdf .................................................... What a wonderful well written article. And references at the end - outstanding. No BS, just tells it like it is. I have seen everything in the article before in different places but it is very convenient to have it all in one place. This article is VERY readable, no hard to understand language. It should be REQUIRED reading for all hams especially for Newbies who have not seen these concepts before. Thanks for a great link Don. Stan K9IUQ
W4LGH2007-03-02
RE: Benchmarks
John...there simply is no hope for you, I believe you are going to argue when your time is up and they come to get you. Something about reflected years were added back to your total # of years allowed. I have done the experiment you siad, and have NEVER seen additional power on the meter, only the reflected power. And it wasn't talking about reflected power on the feed line, it was talking about reflected power on the antenna, since it was out of resonance and the actual sine wave reflected back will cancel the forward sine wave. But thats ok.

I am thru arguing about this, you believe what you want, as they say if you TRUELY believe then it must be so.

Have a nice day!
Reply to a comment by : KD2BD on 2007-03-02

W4LGH wrote: > Signals can be canceled by a phase shift. if you > signals that are equal are 180 degs out of phase they > will cancel, null each other out. I can apply 10 mA of DC current through a resistor in one direction, and apply 10 mA of DC current through the resistor in the other direction, and the net current flow through the resistor will be 0 mA. Yes. I agree. But POWER isn't "cancelled" in the process. Current simply isn't being drawn from the voltage sources. > If you look at the wave forms on your ramdon wire, > the reflected signal can be less <= the forward > signal. Any amount of reflected signal, lets say for > example 10% will subtract from the main signal. Only if nothing is done to re-reflect that energy BACK towards the antenna again. The device that does this is the antenna tuner. A 100-watt transmitter feeding a 3:1 VSWR will see 25 watts in the form of reflected power. This power is potentially lost as heat in the transmitter if nothing is done to correct the situation. If we install a tuner (in the shack), we can adjust it to provide a 50 ohm load to the transmitter (1:1 VSWR). But wait a second! A 1:1 VSWR implies the transmitter is not seeing any reflected power. So, where did it go? Did it get "cancelled" somewhere in the system? No. It got re-reflected back towards the antenna in phase with the incident power and radiated by the antenna. There's an easy way to prove this. Take a good quality directional wattmeter and install it between your transmitter and tuner to measure your forward power (100 W) and verify your reflected power at this point is zero. Move the wattmeter to the OTHER side of the tuner where the 3:1 VSWR exists. There you might see 125 watts of forward power and 25 watts of reflected power. But I only have a 100 watt transmitter! Where did the extra 25 watts come from? There is no extra power. What the wattmeter is showing is the vector product of the incident power from the transmitter (100 W) PLUS the reflected power the tuner has re-reflected back toward the load (25 W). Assuming a lossless tuner and transmission line, the total power radiated by the antenna will be 100 watts in this case, despite the 3:1 VSWR and 25% reflected power. These seemingly odd wattmeter readings make perfect sense when they are understood and interpreted correctly. 73, de John, KD2BD
Reply to a comment by : KD2BD on 2007-03-02

> Energy = Power * Time. This also implies that Power = Energy/Time We know from basic physics that Energy can neither be created nor destroyed. It can only converted from one form to another. So, then how can this statement: > the antenna emits less RF power when non resonant due > to cancellation of RF power. Thus the expected > transmitted power level is not produced. be true? The total RF power in the system is either going to be dissipated by the antenna as electromagnetic radiation, or dissipated as heat in dielectric or IR losses within the system. How, then, is RF power "cancelled" without time being modified or energy being destroyed? Anyone? 73, de John, KD2BD
Reply to a comment by : W4LGH on 2007-03-02

I said I wasn't going to post here anymore, but I did come across this article, that some of you should read. It talks about resonance, what it is and how and why it works. Pay attention to why a resonant antenna does what it does. 73 de W4LGH- Alan ====================================================== AN100 What SWR Does Not Show Written by Bill Ashley, EE for AEA Technology Inc. Abstract: This application note explains the advantage of measuring vector impedance vs. measuring SWR (network analyzer vs. SWR meter). Return loss and SWR express the same property (mismatch) using two different scales. All advantages and disadvantages of an SWR reading also apply to return loss readings. Introduction: The Standing Wave Ratio (SWR) of an antenna and its feedline has long been used to measure an antenna’s transmit efficiency. SWR is a simple concept, you send a unit of RF energy into the feedline, and measure the amount of energy that reflects back. We assume the portion of energy not reflected back transmits out the antenna. The limitations of this measurement usually cause the transmit efficiency to be lower than what SWR predicts. Using a network analyzer to measure vector impedance during antenna alignment improves transmitted efficiency compared to a simple SWR alignment. SWR meters have been around a long time, and many people are reluctant to change because SWR is an easy concept to understand. In the past, SWR meters were less expensive than vector impedance analyzers (aka network analyzers) which has been a determining factor in the SWR popularity. However, as costs in components continue to drop, the vector analyzers have become less expensive than they used to be. Since transmitters are rated in power, we will use the term “power”, not energy, for the remainder of this paper. These two quantities are closely related: Energy = Power * Time. SWR expresses impedance mismatch using the following formula: SWR = Z0/ZL or ZL/Z0 and Return Loss = 20*log(SWR) Use the SWR answer that equals or exceeds 1.0. Z0 is the characteristic impedance of the antenna/feedline, usually 50 ohms. ZL is the total impedance of the antenna/feedline. When SWR is 1.0 there is a perfect match, but this rarely occurs on a real antenna. Vector impedance separates the reactive and resistive components of the impedance. This separation allows the technician or engineer to “see” the impedance in a greater level of detail. Using vector impedance allows one to measure for both match and resonance. Discussion: The first question one might ask about the limitations of SWR: “If the power is not reflected back, where does it go?" The answer: the antenna emits less RF power when non resonant due to cancellation of RF power. Thus the expected transmitted power level is not produced. Vector impedance allows you to see resonant frequency during alignment (SWR doesn’t), so transmitted power can be improved. Now we ask “What is resonance, and how does it improve power”? Resonance in an antenna occurs when its impedance has no reactance, i.e. it is purely resistive. Reactance causes the voltage and current waveforms to shift out of phase with respect to each other (remember ELI the ICE man?). Since power equals voltage times current (P=V*I), the power factor drops below a perfect 1.0 when the V and I waveforms go out of phase and power cancellation occurs. Figure 1 shows an example of power cancellation due to a non resonant load. In this example, a capacitive load causes a 30 degree phase shift. The power produced is shown by the filled in areas, we see that a portion of the power produced went “negative” (blue area). This portion of the power curve is actually out of phase, and cancels out an equal portion (purple area) from the positive region. What is left over (yellow portion) is the actual power available for transmission. Figure 1. Power Cancellation Illustration With a purely reactive load, the power factor goes to 0. This happens because half the transmitted power cancels out the other half. Using a resonant antenna (power factor = 1.0) allows all of the transmitter’s RF power to radiate from the antenna. Table 1. Power Factor vs. Vector Impedance Angle Impedance Angle 0 15 30 45 60 75 90 Power Factor 1.000 0.965 0.866 0.707 0.500 0.259 0.000 The power factor shows the loss that occurs with a reactive load. Depending upon the design, a transmitter may generate even less power when connected to a reactive load. Reactive loads often cause an undesirable increase in the final tube or transistor power dissipation, resulting in degraded transmitter lifetime. Other limitations of SWR meters eliminated by network analyzers: 1. Designed for 50 ohm systems, SWR meters give misleading information for non 50 ohm antenna/feedlines. One case using a 30 ohm antenna had higher transmit efficiencies with the SWR of 1.6 (set resonant at 30 ohms) vs. when (de)tuned to an SWR of 1.2 (reactive load). Using vector impedance solved the “mystery”. 2. There is no method to remove feedline effects from SWR readings. Vector impedance analyzers usually have a cable null feature (open-short-load), so the antenna can be measured with cable effects removed. 3. Cannot produce a Smith Chart plot with SWR data. 4. Most SWR meters use wideband detectors, and are highly susceptible to interfering signals entering the antenna. Network analyzers usually involve some form of signal filtering and offer improved performance in such an environment. Conclusion: To align an antenna for the best efficiency, use vector impedance readings from a network analyzer; do not use an SWR meter or return loss reading.
Reply to a comment by : K9IUQ on 2007-03-02

K6IOU wrote: finally found the correct URL to an excellent article on Antennas and Feedlines . . . covers most of the stuff that has been 'discussed' here lately: http://members.dslextreme.com/users/w6wqc/antennas%20and%20feedlines.pdf .................................................... What a wonderful well written article. And references at the end - outstanding. No BS, just tells it like it is. I have seen everything in the article before in different places but it is very convenient to have it all in one place. This article is VERY readable, no hard to understand language. It should be REQUIRED reading for all hams especially for Newbies who have not seen these concepts before. Thanks for a great link Don. Stan K9IUQ
K9IUQ2007-03-02
Benchmarks
KD2BD wrote;

No. It got re-reflected back towards the antenna in phase with the incident power and radiated by the antenna.

The device that does this is the antenna tuner.



...................................................
But if this is INDEED true than W4LGH's statement "The idea of an antenna tuner hooked to an un-balanced line (coax) is absurd." has to be FALSE?


I have seen this explained many times in the text books, but have never seen it explained in such easy to understand language. You are doing a great service here John. Many concepts that I did not quite understand has gotten much clearer thanks to your well thought out posts.

You will change never W4LGH's *beliefs* but you have helped many of us here expand our knowledge.

Stan K9IUQ
KD2BD2007-03-02
RE: Benchmarks
W4LGH wrote:

> Signals can be canceled by a phase shift. if you
> signals that are equal are 180 degs out of phase they
> will cancel, null each other out.

I can apply 10 mA of DC current through a resistor in one direction, and apply 10 mA of DC current through the resistor in the other direction, and the net current flow through the resistor will be 0 mA.

Yes. I agree.

But POWER isn't "cancelled" in the process. Current simply isn't being drawn from the voltage sources.

> If you look at the wave forms on your ramdon wire,
> the reflected signal can be less <= the forward
> signal. Any amount of reflected signal, lets say for
> example 10% will subtract from the main signal.

Only if nothing is done to re-reflect that energy BACK towards the antenna again. The device that does this is the antenna tuner.

A 100-watt transmitter feeding a 3:1 VSWR will see 25 watts in the form of reflected power. This power is potentially lost as heat in the transmitter if nothing is done to correct the situation.

If we install a tuner (in the shack), we can adjust it to provide a 50 ohm load to the transmitter (1:1 VSWR).

But wait a second! A 1:1 VSWR implies the transmitter is not seeing any reflected power. So, where did it go? Did it get "cancelled" somewhere in the system?

No. It got re-reflected back towards the antenna in phase with the incident power and radiated by the antenna.

There's an easy way to prove this.

Take a good quality directional wattmeter and install it between your transmitter and tuner to measure your forward power (100 W) and verify your reflected power at this point is zero.

Move the wattmeter to the OTHER side of the tuner where the 3:1 VSWR exists. There you might see 125 watts of forward power and 25 watts of reflected power.

But I only have a 100 watt transmitter! Where did the extra 25 watts come from?

There is no extra power. What the wattmeter is showing is the vector product of the incident power from the transmitter (100 W) PLUS the reflected power the tuner has re-reflected back toward the load (25 W).

Assuming a lossless tuner and transmission line, the total power radiated by the antenna will be 100 watts in this case, despite the 3:1 VSWR and 25% reflected power.

These seemingly odd wattmeter readings make perfect sense when they are understood and interpreted correctly.


73, de John, KD2BD
Reply to a comment by : KD2BD on 2007-03-02

> Energy = Power * Time. This also implies that Power = Energy/Time We know from basic physics that Energy can neither be created nor destroyed. It can only converted from one form to another. So, then how can this statement: > the antenna emits less RF power when non resonant due > to cancellation of RF power. Thus the expected > transmitted power level is not produced. be true? The total RF power in the system is either going to be dissipated by the antenna as electromagnetic radiation, or dissipated as heat in dielectric or IR losses within the system. How, then, is RF power "cancelled" without time being modified or energy being destroyed? Anyone? 73, de John, KD2BD
Reply to a comment by : W4LGH on 2007-03-02

I said I wasn't going to post here anymore, but I did come across this article, that some of you should read. It talks about resonance, what it is and how and why it works. Pay attention to why a resonant antenna does what it does. 73 de W4LGH- Alan ====================================================== AN100 What SWR Does Not Show Written by Bill Ashley, EE for AEA Technology Inc. Abstract: This application note explains the advantage of measuring vector impedance vs. measuring SWR (network analyzer vs. SWR meter). Return loss and SWR express the same property (mismatch) using two different scales. All advantages and disadvantages of an SWR reading also apply to return loss readings. Introduction: The Standing Wave Ratio (SWR) of an antenna and its feedline has long been used to measure an antenna’s transmit efficiency. SWR is a simple concept, you send a unit of RF energy into the feedline, and measure the amount of energy that reflects back. We assume the portion of energy not reflected back transmits out the antenna. The limitations of this measurement usually cause the transmit efficiency to be lower than what SWR predicts. Using a network analyzer to measure vector impedance during antenna alignment improves transmitted efficiency compared to a simple SWR alignment. SWR meters have been around a long time, and many people are reluctant to change because SWR is an easy concept to understand. In the past, SWR meters were less expensive than vector impedance analyzers (aka network analyzers) which has been a determining factor in the SWR popularity. However, as costs in components continue to drop, the vector analyzers have become less expensive than they used to be. Since transmitters are rated in power, we will use the term “power”, not energy, for the remainder of this paper. These two quantities are closely related: Energy = Power * Time. SWR expresses impedance mismatch using the following formula: SWR = Z0/ZL or ZL/Z0 and Return Loss = 20*log(SWR) Use the SWR answer that equals or exceeds 1.0. Z0 is the characteristic impedance of the antenna/feedline, usually 50 ohms. ZL is the total impedance of the antenna/feedline. When SWR is 1.0 there is a perfect match, but this rarely occurs on a real antenna. Vector impedance separates the reactive and resistive components of the impedance. This separation allows the technician or engineer to “see” the impedance in a greater level of detail. Using vector impedance allows one to measure for both match and resonance. Discussion: The first question one might ask about the limitations of SWR: “If the power is not reflected back, where does it go?" The answer: the antenna emits less RF power when non resonant due to cancellation of RF power. Thus the expected transmitted power level is not produced. Vector impedance allows you to see resonant frequency during alignment (SWR doesn’t), so transmitted power can be improved. Now we ask “What is resonance, and how does it improve power”? Resonance in an antenna occurs when its impedance has no reactance, i.e. it is purely resistive. Reactance causes the voltage and current waveforms to shift out of phase with respect to each other (remember ELI the ICE man?). Since power equals voltage times current (P=V*I), the power factor drops below a perfect 1.0 when the V and I waveforms go out of phase and power cancellation occurs. Figure 1 shows an example of power cancellation due to a non resonant load. In this example, a capacitive load causes a 30 degree phase shift. The power produced is shown by the filled in areas, we see that a portion of the power produced went “negative” (blue area). This portion of the power curve is actually out of phase, and cancels out an equal portion (purple area) from the positive region. What is left over (yellow portion) is the actual power available for transmission. Figure 1. Power Cancellation Illustration With a purely reactive load, the power factor goes to 0. This happens because half the transmitted power cancels out the other half. Using a resonant antenna (power factor = 1.0) allows all of the transmitter’s RF power to radiate from the antenna. Table 1. Power Factor vs. Vector Impedance Angle Impedance Angle 0 15 30 45 60 75 90 Power Factor 1.000 0.965 0.866 0.707 0.500 0.259 0.000 The power factor shows the loss that occurs with a reactive load. Depending upon the design, a transmitter may generate even less power when connected to a reactive load. Reactive loads often cause an undesirable increase in the final tube or transistor power dissipation, resulting in degraded transmitter lifetime. Other limitations of SWR meters eliminated by network analyzers: 1. Designed for 50 ohm systems, SWR meters give misleading information for non 50 ohm antenna/feedlines. One case using a 30 ohm antenna had higher transmit efficiencies with the SWR of 1.6 (set resonant at 30 ohms) vs. when (de)tuned to an SWR of 1.2 (reactive load). Using vector impedance solved the “mystery”. 2. There is no method to remove feedline effects from SWR readings. Vector impedance analyzers usually have a cable null feature (open-short-load), so the antenna can be measured with cable effects removed. 3. Cannot produce a Smith Chart plot with SWR data. 4. Most SWR meters use wideband detectors, and are highly susceptible to interfering signals entering the antenna. Network analyzers usually involve some form of signal filtering and offer improved performance in such an environment. Conclusion: To align an antenna for the best efficiency, use vector impedance readings from a network analyzer; do not use an SWR meter or return loss reading.
Reply to a comment by : K9IUQ on 2007-03-02

K6IOU wrote: finally found the correct URL to an excellent article on Antennas and Feedlines . . . covers most of the stuff that has been 'discussed' here lately: http://members.dslextreme.com/users/w6wqc/antennas%20and%20feedlines.pdf .................................................... What a wonderful well written article. And references at the end - outstanding. No BS, just tells it like it is. I have seen everything in the article before in different places but it is very convenient to have it all in one place. This article is VERY readable, no hard to understand language. It should be REQUIRED reading for all hams especially for Newbies who have not seen these concepts before. Thanks for a great link Don. Stan K9IUQ
W4LGH2007-03-02
RE: Benchmarks
Signals can be canceled by a phase shift. if you signals that are equal are 180 degs out of phase they will cancel, null each other out. If you look at the wave forms on your ramdon wire, the reflected signal can be less <= the forward signal. Any amount of reflected signal, lets say for example 10% will subtract from the main signal. These are FACTS gentlemen, and used everyday to design circuits. This is also what I have bene trying to say about resonance.

Anyway, yall have fun...do whatever works for you to your satifaction. Lots of new discoveries have been made over the past 10 years, that change waht was written 60 years ago. New tests have been developed, etc...but I have grown tired of trying to explain it.
Also in the previous article link that was posted, did you read where the antenna matching network was at the antenna?

RF is RF gentleman whether is is 100Kc or 100Ghz, it all behaves the same way at the antenna.

DONE, OVER AND OUT!
de W4LGH - Alan


Reply to a comment by : KD2BD on 2007-03-02

> Energy = Power * Time. This also implies that Power = Energy/Time We know from basic physics that Energy can neither be created nor destroyed. It can only converted from one form to another. So, then how can this statement: > the antenna emits less RF power when non resonant due > to cancellation of RF power. Thus the expected > transmitted power level is not produced. be true? The total RF power in the system is either going to be dissipated by the antenna as electromagnetic radiation, or dissipated as heat in dielectric or IR losses within the system. How, then, is RF power "cancelled" without time being modified or energy being destroyed? Anyone? 73, de John, KD2BD
Reply to a comment by : W4LGH on 2007-03-02

I said I wasn't going to post here anymore, but I did come across this article, that some of you should read. It talks about resonance, what it is and how and why it works. Pay attention to why a resonant antenna does what it does. 73 de W4LGH- Alan ====================================================== AN100 What SWR Does Not Show Written by Bill Ashley, EE for AEA Technology Inc. Abstract: This application note explains the advantage of measuring vector impedance vs. measuring SWR (network analyzer vs. SWR meter). Return loss and SWR express the same property (mismatch) using two different scales. All advantages and disadvantages of an SWR reading also apply to return loss readings. Introduction: The Standing Wave Ratio (SWR) of an antenna and its feedline has long been used to measure an antenna’s transmit efficiency. SWR is a simple concept, you send a unit of RF energy into the feedline, and measure the amount of energy that reflects back. We assume the portion of energy not reflected back transmits out the antenna. The limitations of this measurement usually cause the transmit efficiency to be lower than what SWR predicts. Using a network analyzer to measure vector impedance during antenna alignment improves transmitted efficiency compared to a simple SWR alignment. SWR meters have been around a long time, and many people are reluctant to change because SWR is an easy concept to understand. In the past, SWR meters were less expensive than vector impedance analyzers (aka network analyzers) which has been a determining factor in the SWR popularity. However, as costs in components continue to drop, the vector analyzers have become less expensive than they used to be. Since transmitters are rated in power, we will use the term “power”, not energy, for the remainder of this paper. These two quantities are closely related: Energy = Power * Time. SWR expresses impedance mismatch using the following formula: SWR = Z0/ZL or ZL/Z0 and Return Loss = 20*log(SWR) Use the SWR answer that equals or exceeds 1.0. Z0 is the characteristic impedance of the antenna/feedline, usually 50 ohms. ZL is the total impedance of the antenna/feedline. When SWR is 1.0 there is a perfect match, but this rarely occurs on a real antenna. Vector impedance separates the reactive and resistive components of the impedance. This separation allows the technician or engineer to “see” the impedance in a greater level of detail. Using vector impedance allows one to measure for both match and resonance. Discussion: The first question one might ask about the limitations of SWR: “If the power is not reflected back, where does it go?" The answer: the antenna emits less RF power when non resonant due to cancellation of RF power. Thus the expected transmitted power level is not produced. Vector impedance allows you to see resonant frequency during alignment (SWR doesn’t), so transmitted power can be improved. Now we ask “What is resonance, and how does it improve power”? Resonance in an antenna occurs when its impedance has no reactance, i.e. it is purely resistive. Reactance causes the voltage and current waveforms to shift out of phase with respect to each other (remember ELI the ICE man?). Since power equals voltage times current (P=V*I), the power factor drops below a perfect 1.0 when the V and I waveforms go out of phase and power cancellation occurs. Figure 1 shows an example of power cancellation due to a non resonant load. In this example, a capacitive load causes a 30 degree phase shift. The power produced is shown by the filled in areas, we see that a portion of the power produced went “negative” (blue area). This portion of the power curve is actually out of phase, and cancels out an equal portion (purple area) from the positive region. What is left over (yellow portion) is the actual power available for transmission. Figure 1. Power Cancellation Illustration With a purely reactive load, the power factor goes to 0. This happens because half the transmitted power cancels out the other half. Using a resonant antenna (power factor = 1.0) allows all of the transmitter’s RF power to radiate from the antenna. Table 1. Power Factor vs. Vector Impedance Angle Impedance Angle 0 15 30 45 60 75 90 Power Factor 1.000 0.965 0.866 0.707 0.500 0.259 0.000 The power factor shows the loss that occurs with a reactive load. Depending upon the design, a transmitter may generate even less power when connected to a reactive load. Reactive loads often cause an undesirable increase in the final tube or transistor power dissipation, resulting in degraded transmitter lifetime. Other limitations of SWR meters eliminated by network analyzers: 1. Designed for 50 ohm systems, SWR meters give misleading information for non 50 ohm antenna/feedlines. One case using a 30 ohm antenna had higher transmit efficiencies with the SWR of 1.6 (set resonant at 30 ohms) vs. when (de)tuned to an SWR of 1.2 (reactive load). Using vector impedance solved the “mystery”. 2. There is no method to remove feedline effects from SWR readings. Vector impedance analyzers usually have a cable null feature (open-short-load), so the antenna can be measured with cable effects removed. 3. Cannot produce a Smith Chart plot with SWR data. 4. Most SWR meters use wideband detectors, and are highly susceptible to interfering signals entering the antenna. Network analyzers usually involve some form of signal filtering and offer improved performance in such an environment. Conclusion: To align an antenna for the best efficiency, use vector impedance readings from a network analyzer; do not use an SWR meter or return loss reading.
Reply to a comment by : K9IUQ on 2007-03-02

K6IOU wrote: finally found the correct URL to an excellent article on Antennas and Feedlines . . . covers most of the stuff that has been 'discussed' here lately: http://members.dslextreme.com/users/w6wqc/antennas%20and%20feedlines.pdf .................................................... What a wonderful well written article. And references at the end - outstanding. No BS, just tells it like it is. I have seen everything in the article before in different places but it is very convenient to have it all in one place. This article is VERY readable, no hard to understand language. It should be REQUIRED reading for all hams especially for Newbies who have not seen these concepts before. Thanks for a great link Don. Stan K9IUQ
KD2BD2007-03-02
RE: Benchmarks
> Energy = Power * Time.

This also implies that Power = Energy/Time

We know from basic physics that Energy can neither be created nor destroyed. It can only converted from one form to another.

So, then how can this statement:

> the antenna emits less RF power when non resonant due
> to cancellation of RF power. Thus the expected
> transmitted power level is not produced.

be true?

The total RF power in the system is either going to be dissipated by the antenna as electromagnetic radiation, or dissipated as heat in dielectric or IR losses within the system.

How, then, is RF power "cancelled" without time being modified or energy being destroyed?

Anyone?


73, de John, KD2BD
Reply to a comment by : W4LGH on 2007-03-02

I said I wasn't going to post here anymore, but I did come across this article, that some of you should read. It talks about resonance, what it is and how and why it works. Pay attention to why a resonant antenna does what it does. 73 de W4LGH- Alan ====================================================== AN100 What SWR Does Not Show Written by Bill Ashley, EE for AEA Technology Inc. Abstract: This application note explains the advantage of measuring vector impedance vs. measuring SWR (network analyzer vs. SWR meter). Return loss and SWR express the same property (mismatch) using two different scales. All advantages and disadvantages of an SWR reading also apply to return loss readings. Introduction: The Standing Wave Ratio (SWR) of an antenna and its feedline has long been used to measure an antenna’s transmit efficiency. SWR is a simple concept, you send a unit of RF energy into the feedline, and measure the amount of energy that reflects back. We assume the portion of energy not reflected back transmits out the antenna. The limitations of this measurement usually cause the transmit efficiency to be lower than what SWR predicts. Using a network analyzer to measure vector impedance during antenna alignment improves transmitted efficiency compared to a simple SWR alignment. SWR meters have been around a long time, and many people are reluctant to change because SWR is an easy concept to understand. In the past, SWR meters were less expensive than vector impedance analyzers (aka network analyzers) which has been a determining factor in the SWR popularity. However, as costs in components continue to drop, the vector analyzers have become less expensive than they used to be. Since transmitters are rated in power, we will use the term “power”, not energy, for the remainder of this paper. These two quantities are closely related: Energy = Power * Time. SWR expresses impedance mismatch using the following formula: SWR = Z0/ZL or ZL/Z0 and Return Loss = 20*log(SWR) Use the SWR answer that equals or exceeds 1.0. Z0 is the characteristic impedance of the antenna/feedline, usually 50 ohms. ZL is the total impedance of the antenna/feedline. When SWR is 1.0 there is a perfect match, but this rarely occurs on a real antenna. Vector impedance separates the reactive and resistive components of the impedance. This separation allows the technician or engineer to “see” the impedance in a greater level of detail. Using vector impedance allows one to measure for both match and resonance. Discussion: The first question one might ask about the limitations of SWR: “If the power is not reflected back, where does it go?" The answer: the antenna emits less RF power when non resonant due to cancellation of RF power. Thus the expected transmitted power level is not produced. Vector impedance allows you to see resonant frequency during alignment (SWR doesn’t), so transmitted power can be improved. Now we ask “What is resonance, and how does it improve power”? Resonance in an antenna occurs when its impedance has no reactance, i.e. it is purely resistive. Reactance causes the voltage and current waveforms to shift out of phase with respect to each other (remember ELI the ICE man?). Since power equals voltage times current (P=V*I), the power factor drops below a perfect 1.0 when the V and I waveforms go out of phase and power cancellation occurs. Figure 1 shows an example of power cancellation due to a non resonant load. In this example, a capacitive load causes a 30 degree phase shift. The power produced is shown by the filled in areas, we see that a portion of the power produced went “negative” (blue area). This portion of the power curve is actually out of phase, and cancels out an equal portion (purple area) from the positive region. What is left over (yellow portion) is the actual power available for transmission. Figure 1. Power Cancellation Illustration With a purely reactive load, the power factor goes to 0. This happens because half the transmitted power cancels out the other half. Using a resonant antenna (power factor = 1.0) allows all of the transmitter’s RF power to radiate from the antenna. Table 1. Power Factor vs. Vector Impedance Angle Impedance Angle 0 15 30 45 60 75 90 Power Factor 1.000 0.965 0.866 0.707 0.500 0.259 0.000 The power factor shows the loss that occurs with a reactive load. Depending upon the design, a transmitter may generate even less power when connected to a reactive load. Reactive loads often cause an undesirable increase in the final tube or transistor power dissipation, resulting in degraded transmitter lifetime. Other limitations of SWR meters eliminated by network analyzers: 1. Designed for 50 ohm systems, SWR meters give misleading information for non 50 ohm antenna/feedlines. One case using a 30 ohm antenna had higher transmit efficiencies with the SWR of 1.6 (set resonant at 30 ohms) vs. when (de)tuned to an SWR of 1.2 (reactive load). Using vector impedance solved the “mystery”. 2. There is no method to remove feedline effects from SWR readings. Vector impedance analyzers usually have a cable null feature (open-short-load), so the antenna can be measured with cable effects removed. 3. Cannot produce a Smith Chart plot with SWR data. 4. Most SWR meters use wideband detectors, and are highly susceptible to interfering signals entering the antenna. Network analyzers usually involve some form of signal filtering and offer improved performance in such an environment. Conclusion: To align an antenna for the best efficiency, use vector impedance readings from a network analyzer; do not use an SWR meter or return loss reading.
Reply to a comment by : K9IUQ on 2007-03-02

K6IOU wrote: finally found the correct URL to an excellent article on Antennas and Feedlines . . . covers most of the stuff that has been 'discussed' here lately: http://members.dslextreme.com/users/w6wqc/antennas%20and%20feedlines.pdf .................................................... What a wonderful well written article. And references at the end - outstanding. No BS, just tells it like it is. I have seen everything in the article before in different places but it is very convenient to have it all in one place. This article is VERY readable, no hard to understand language. It should be REQUIRED reading for all hams especially for Newbies who have not seen these concepts before. Thanks for a great link Don. Stan K9IUQ
KD2BD2007-03-02
RE: Benchmarks
W4LGH wrote:

> KB2DB further writes..."By definition, at resonance
> the feedpoint impedance is 100% resistive."

Actually, it wasn't KB2DB who made that statement in this thread, nor was it KD2BD. It was K6IOU on March 1, and I fully agree with Don's statement.

>> KD2BD wrote..."The difference between doing this
>> on AM vs. FM or TV is that the FM or TV antennas
>> used in diplexed applications have HUGE bandwidths,
>> and are therefore resonant (and impedance matched,
>> and provide a respectable antenna pattern (gain))
>> for each station sharing the common antenna. "
> ============
> Now isn't this an interesting statement out of a man
> who say resonance is NOT a factor.

Wrong again, Al. I did not say that. I said the antennas in question ARE resonant over a wide range of frequencies.

The broadband antennas used in VHF and UHF diplexed broadcasting applications (including Batwings, Panels, and Traveling Wave (sidefire helical) antennas) are designed to maintain a constant impedance and desirable radiation pattern over a fairly wide range of frequencies. A Batwing array designed to cover VHF-TV channels 4 and 5 is resonant across the entire 66 to 82 MHz region (and then some!).

The methods used to diplex and combine each transmitter into a broadband antenna system DO NOT tune the antenna to resonance at each transmitting frequency. They merely serve as bandpass and reject filters to isolate one transmitter from the next (not unlike a duplexer in an FM repeater system).

> It is all 100% the same, it resonant, therefore
> the impedance is matched and provides a respectable
> pattern! 100% Correct, and 100% the same for HAM
> radio.

God is love.
Love is blind.
Ray Charles is blind.
Therefore, Ray Charles is God.

I can have an antenna that presents a feedpoint impedance of 21+0j ohms at a particular operating frequency. The antenna is resonant at that frequency (according to the definition above). The fact that it is resonant does not necessarily imply the antenna is going to provide a good match to my 50 ohm transmitter and transmission line. In fact, connecting it directly to a 50 ohm system will likely throw it OUT of resonance if an appropriate LC network isn't used somewhere in the system to correct the mismatch.

In another case, I can have a yagi that exhibits a feedpoint impedance of 50+0j ohms, and therefore presents a very respectable 1:1 VSWR to my 50 ohm transmitter and feedline. But it can have very high sidelobes and more radiation off the back than the front.

Is that a "respectable pattern".

No, it isn't.

But it's resonant!

It doesn't matter.

Ray Charles isn't God.


73, de John, KD2BD
Reply to a comment by : W4LGH on 2007-03-01

KD2BD wrote..."The difference between doing this on AM vs. FM or TV is that the FM or TV antennas used in diplexed applications have HUGE bandwidths, and are therefore resonant (and impedance matched, and provide a respectable antenna pattern (gain)) for each station sharing the common antenna. " ============ Now isn't this an interesting statement out of a man who say resonance is NOT a factor. What he said in that response, is exactly what I have been saying. It applies to ALL frequencies, and NOT just the higher ones. It is all 100% the same, it resonant, therefore the impedance is matched and provides a respectable pattern! 100% Correct, and 100% the same for HAM radio. ============ You guys are really something else. There are posts saying you can use a tuner in your shack hooked to coax, and that you can tune your antenna. Again, I say you can not tune the ANTENNA, you can however match the impedance of the coax to the tuner. With an average run of 100' of RG8X, the losses are to great. I have never said you could not do this with OPEN line...as a matter of fact I said you could do this, but you still has some loss, probably more acceptable than coax. ============= KB2DB further writes..."By definition, at resonance the feedpoint impedance is 100% resistive." This statement is only true in the fact that @ resonance the feedpoint is 100% resistive, however there is a lot more to the definition of a resonant antenna. You need to go back and read about resonanace in circuits and antennas. There is a lot more to it. ============= In any event, yall have turned around what has been said, read into it either to much, and/or not enough, or totally by your own interpitation as to what you wanted it to say. Some like KB2DB, has gone as far to contradict himself. (where, read above in quotes) This IS the last POST by me. It has totally worn me out with all this cutting and pasting, he said, you said, they said, crap. Some of you have a fairly good concept of whats actually happening, some are so far off it isn't funny. Some want to argue over .1db loss which they say doesn't count, but none the less is a loss, which proves what I have been saying, whether it is .001db or 10db, it is a loss over a resonant antenna. You do it your way, and I'll do it my way. Right wrong or indifferent, I know yall can work anybody you hear! Thats about as stupid a statement as saying you always find what you are looking for the last place you look! Well you gotta be a complete idiot if you keep looking for it after you found it, so it will always be the last place you look, even if its the first place. Can work anybody I hear...same thing...how can you work them if you don't hear them? Frog hair can only be split so many times, and its way past that limit! YALL HAVE WON!! (but that doesn't make you right) de W4LGH OUT/QRT on eHam Have fun!!
Reply to a comment by : N4SL on 2007-03-01

MUST LOOK AWAY. MUST LOOK AWAY. CANNOT DO IT.
Reply to a comment by : KD2BD on 2007-03-01

W4LGH wrote: > In the case of these 2 stations in NY, you even read > that one has a STRONGER signal than the other one, > why, because the antenna (tower) is closer to its > resonance. WRONG. It has nothing to do with resonance. It has everything to do with antenna radiation PATTERN! It is the same reason a quarter-wave vertical will produce a stronger groundwave signal than a 3/4 wave vertical. Both are natural resonant lengths, but the 3/4 wave vertical produces greater radiation at higher elevation angles than does the quarter wave, thereby producing a weaker groundwave signal. Wrong again, Al. Wrong again... I'm still waiting for your "hardcore" proof that a 75-meter half-wave dipole fed with RG/8 through a well-designed tuner in the shack cannot become a resonant system on 18 MHz. Where is it? 73, de John, KD2BD
Reply to a comment by : KD2BD on 2007-03-01

N4KC wrote: > John, I wasn't very clear in my statement. I believe > what you are actually bringing to resonance with a > tuner is the antenna system, not just the antenna. > Correct me if I misspoke. After 45 years as a ham, > I'm STILL learning about antennas. So's everyone else. :-) You are correct. The combination of the tuner, the transmission line, and the radiator are brought into resonance, and the resulting impedance matched to the transmitter with proper use of the tuner, regardless of its location in the system. > Also, it is common for not only AM stations but also > broadcast FM and TV stations to use the same antenna > even though they are on very different frequencies. Correct. The difference between doing this on AM vs. FM or TV is that the FM or TV antennas used in diplexed applications have HUGE bandwidths, and are therefore resonant (and impedance matched, and provide a respectable antenna pattern (gain)) for each station sharing the common antenna. An AM tower on the other hand, is seldom more than 10 or so kHz wide in bandwidth, so the specific resonant frequencies in a diplexed AM installation must be established through LC networks in the "shack". The height of the tower in this case simply establishes the antenna's radiation pattern, not necessarily the antenna's resonant frequency. It's done MUCH more often in the FM and television world. In fact, with the advent of HDTV, many UHF broadcasters have replaced their single channel antennas (Pylons) with broadband panel arrays to be able to diplex both their analog and digital channels through a single antenna and feedline. This saves tower space, and helps to maintain equal coverage between each service. > And the diplexer is typically located at the > transmitters, on the ground, not a thousand feet > up the tower. Nor do they ever use open wire > feedline. Imagine that... :-) Some UHF broadcasters even use waveguide. :-O > Don N4KC 73, de John, KD2BD
Reply to a comment by : KD2BD on 2007-03-01

K1DA wrote: > The interesting about 660 and 880 am is that if you > live within groundwave range of them, 660 has a better > signal. They both have killer signals into Rhode Island > during the day. WFAN is stronger because the tower is slightly taller than it should be for optimum performance at 880 kHz. The antenna is a compromise in that regard. 73, de John, KD2BD
Reply to a comment by : K1DA on 2007-03-01

The interesting about 660 and 880 am is that if you live within groundwave range of them, 660 has a better signal. They both have killer signals into Rhode Island during the day.
Reply to a comment by : KD2BD on 2007-03-01

N4KC wrote: > I'm not sure anyone here has said that you can "tune > an antenna into resonance" with a "tuner." If they > did, they are incorrect. Don, actually, you CAN. It is well understood that an antenna's natural resonant frequency can easily be modified through an LC network at the feedpoint. It can ALSO be changed in the shack at the other end of the feedline using a similar network, or anywhere else in between, for that matter. Other than the additional loss incurred in the feedline, it does not matter whether the LC network (tuner) is at the feedpoint, or in the shack. The natural resonant frequency of the antenna IS MODIFIED nonetheless through the tuning network. This is what makes it possible to use a 75-meter dipole on 17 through a tuner, or a dipole cut for the phone portion of 75 on the CW portion as well. The tuner allows the antenna system's resonant frequency to be changed to our desired operating frequency without having to change its physical length. It does more than simply match impedances. Realizing a tuning network can modify a single antenna's resonant frequency makes for some VERY interesting possibilities. A pair of tuners properly diplexed into a single antenna can provide perfect resonance on two separate frequencies SIMULTANEOUSLY! That's right! Here's a "real world" example: http://www.fybush.com/site-030424.html This web page describes the operation of two radio stations, WFAN and WCBS, both 50 kW AM stations, 220 kHz apart in frequency, that operate SIMULTANEOUSLY into a single radiating tower. There is a photo toward the bottom of the page that shows a SINGLE length of coaxial transmission line feeding the combined 100 kW carrier (400 kW PEP) from both transmitters into the base of the tower. Originally, the tower included parallel-tuned "traps" toward the top (just like a ham's trap vertical antenna) to establish individual points of resonance at each radio stations' frequency. However, the current arrangement that completely eliminates the traps and instead establishes points of resonance in the antenna tuning network for each transmitter has proven to be a superior approach. 73, de John, KD2BD
Reply to a comment by : KD2BD on 2007-03-01

W4LGH wrote: > Now if you truely believe a tuner in your shack > hooked to coax, will make a 75meter dipole resonant > on 17meters, you have no idea what resonant is or > means, and I can and will gladly show you "HARDCORE > PROOF" that this is NOT so! PROOF that you can see > with your OWN eyes! I don't "believe" a tuner in your shack connected to a coax-fed dipole cut for 75 can be made to resonate on 17. I know it for a fact. A 5/8ths wave vertical isn't a "natural" resonant length for a radiator. Yet, combined with a proper resonating and impedance matching network, it can not only resonate where we want, it also provides some gain (vertical directivity) over a "naturally resonant" quarter wavelength antenna without the additional matching network. So, go ahead. Start off simple. Demonstrate your "hardcore" proof that a 75-meter half-wave dipole fed with RG/8 through a well-designed tuner in the shack cannot become a resonant system on 18 MHz. First, please begin with your definition of "resonant". And please stay away from Wikipedia this time. I want to hear YOUR definition, because as you stated earlier, textbooks are only good as a "starting point". The floor is yours. 73, de John, KD2BD
Reply to a comment by : W4LGH on 2007-02-28

KD2BD wrote..."Standing Wave antennas, on the other hand, are resonant, including operating on 17 meters with a 75 meter coax fed dipole through a tuner. Adjusting the antenna tuner in the shack for a 50 ohm resistive output impedance in this case MAKES THE 75-METER ANTENNA SYSTEM RESONANT ON 17 METERS! And you were proven otherwise. Many times." ======== I fail to see where I have been PROVEN wrong at all. No proof has been offered, other than whats been written in books, and some standard math formulas, that we all know. And I have said, they are great for a starting point. Now if you truely believe a tuner in your shack hooked to coax, will make a 75meter dipole resonant on 17meters, you have no idea what resonant is or means, and I can and will gladly show you "HARDCORE PROOF" that this is NOT so! PROOF that you can see with your OWN eyes! Now will it make it work? To some degree, by fooling your transmitter to load into the tuner, which again, you could do with a 48" whip hooked to it. You can post until you are BLUE that this is SO, and again, I will SHOW you PROOF that is is NOT! If it was SO, there would be (1)antenna manufacture that would build 1 antenna the same for everything out there and you then buy your antenna tuner and hook it up to load it. This simply isn't so, and MILLIONS of $$$ are spent every year to improve on antenna design & efficiency. I just don't understand why hams want to continue to live in the dark ages. All of what I have said is also documented and can simply be seen, just looking around. You can load your 80m dipole up on 2meters if you have enough capacitance & inductance to tune out the reactance at the end of the coax, but it doesn't make it resoanant or efficient on 2 meters. If what you and several others have been trying to make other believe, there is one (1) antenna to fit all, just plug in your tuner. NO..it doesn't work that way! And there is NO technical refferance that has ever supported that theory. Broadcaster, cell phone companys and Hams have certainly wasted lots of money going on what you are trying to say. Wake up and smell the coffee man...Stop misleading the hams on here and stop trying to make me look like a fool, neither is correct. You simply CAN NOT TUNE the resonant frequency of the antenna by changing the reactance/impedance or resistance with a tuner in your shack hooked to un-balanced coax. 73 de W4LGH - Alan http://www.w4lgh.com
Reply to a comment by : N4SL on 2007-02-28

I Like Cake.
Reply to a comment by : ONAIR on 2007-02-22

Interesting point. So a resonant vertical dipole would then be a lot more efficient than a vertical that you would need to tune?
W4LGH2007-03-02
RE: Benchmarks
I said I wasn't going to post here anymore, but I did come across this article, that some of you should read. It talks about resonance, what it is and how and why it works. Pay attention to why a resonant antenna does what it does.
73 de W4LGH- Alan

======================================================
AN100
What SWR Does Not Show

Written by Bill Ashley, EE for
AEA Technology Inc.

Abstract:
This application note explains the advantage of measuring vector impedance vs. measuring SWR (network analyzer vs. SWR meter). Return loss and SWR express the same property (mismatch) using two different scales. All advantages and disadvantages of an SWR reading also apply to return loss readings.

Introduction:
The Standing Wave Ratio (SWR) of an antenna and its feedline has long been used to measure an antenna’s transmit efficiency. SWR is a simple concept, you send a unit of RF energy into the feedline, and measure the amount of energy that reflects back. We assume the portion of energy not reflected back transmits out the antenna. The limitations of this measurement usually cause the transmit efficiency to be lower than what SWR predicts. Using a network analyzer to measure vector impedance during antenna alignment improves transmitted efficiency compared to a simple SWR alignment.

SWR meters have been around a long time, and many people are reluctant to change because SWR is an easy concept to understand. In the past, SWR meters were less expensive than vector impedance analyzers (aka network analyzers) which has been a determining factor in the SWR popularity. However, as costs in components continue to drop, the vector analyzers have become less expensive than they used to be.

Since transmitters are rated in power, we will use the term “power”, not energy, for the remainder of this paper. These two quantities are closely related: Energy = Power * Time.
SWR expresses impedance mismatch using the following formula:

SWR = Z0/ZL or ZL/Z0 and
Return Loss = 20*log(SWR)

Use the SWR answer that equals or exceeds 1.0. Z0 is the characteristic impedance of the antenna/feedline, usually 50 ohms. ZL is the total impedance of the antenna/feedline. When SWR is 1.0 there is a perfect match, but this rarely occurs on a real antenna.

Vector impedance separates the reactive and resistive components of the impedance. This separation allows the technician or engineer to “see” the impedance in a greater level of detail. Using vector impedance allows one to measure for both match and resonance.

Discussion:
The first question one might ask about the limitations of SWR: “If the power is not reflected back, where does it go?" The answer: the antenna emits less RF power when non resonant due to cancellation of RF power. Thus the expected transmitted power level is not produced. Vector impedance allows you to see resonant frequency during alignment (SWR doesn’t), so transmitted power can be improved.

Now we ask “What is resonance, and how does it improve power”?
Resonance in an antenna occurs when its impedance has no reactance, i.e. it is purely resistive. Reactance causes the voltage and current waveforms to shift out of phase with respect to each other (remember ELI the ICE man?). Since power equals voltage times current (P=V*I), the power factor drops below a perfect 1.0 when the V and I waveforms go out of phase and power cancellation occurs. Figure 1 shows an example of power cancellation due to a non resonant load. In this example, a capacitive load causes a 30 degree phase shift. The power produced is shown by the filled in areas, we see that a portion of the power produced went “negative” (blue area). This portion of the power curve is actually out of phase, and cancels out an equal portion (purple area) from the positive region. What is left over (yellow portion) is the actual power available for transmission.

Figure 1. Power Cancellation Illustration


With a purely reactive load, the power factor goes to 0. This happens because half the transmitted power cancels out the other half. Using a resonant antenna (power factor = 1.0) allows all of the transmitter’s RF power to radiate from the antenna.
Table 1. Power Factor vs. Vector Impedance Angle
Impedance Angle 0 15 30 45 60 75 90
Power Factor 1.000 0.965 0.866 0.707 0.500 0.259 0.000

The power factor shows the loss that occurs with a reactive load. Depending upon the design, a transmitter may generate even less power when connected to a reactive load. Reactive loads often cause an undesirable increase in the final tube or transistor power dissipation, resulting in degraded transmitter lifetime.
Other limitations of SWR meters eliminated by network analyzers:
1. Designed for 50 ohm systems, SWR meters give misleading information for non 50 ohm antenna/feedlines. One case using a 30 ohm antenna had higher transmit efficiencies with the SWR of 1.6 (set resonant at 30 ohms) vs. when (de)tuned to an SWR of 1.2 (reactive load). Using vector impedance solved the “mystery”.
2. There is no method to remove feedline effects from SWR readings. Vector impedance analyzers usually have a cable null feature (open-short-load), so the antenna can be measured with cable effects removed.
3. Cannot produce a Smith Chart plot with SWR data.
4. Most SWR meters use wideband detectors, and are highly susceptible to interfering signals entering the antenna. Network analyzers usually involve some form of signal filtering and offer improved performance in such an environment.

Conclusion:
To align an antenna for the best efficiency, use vector impedance readings from a network analyzer; do not use an SWR meter or return loss reading.
Reply to a comment by : K9IUQ on 2007-03-02

K6IOU wrote: finally found the correct URL to an excellent article on Antennas and Feedlines . . . covers most of the stuff that has been 'discussed' here lately: http://members.dslextreme.com/users/w6wqc/antennas%20and%20feedlines.pdf .................................................... What a wonderful well written article. And references at the end - outstanding. No BS, just tells it like it is. I have seen everything in the article before in different places but it is very convenient to have it all in one place. This article is VERY readable, no hard to understand language. It should be REQUIRED reading for all hams especially for Newbies who have not seen these concepts before. Thanks for a great link Don. Stan K9IUQ
K9IUQ2007-03-02
Benchmarks
K6IOU wrote: finally found the correct URL to an excellent article on Antennas and Feedlines . . . covers most of the stuff that has been 'discussed' here lately:

http://members.dslextreme.com/users/w6wqc/antennas%20and%20feedlines.pdf


....................................................
What a wonderful well written article. And references at the end - outstanding. No BS, just tells it like it is. I have seen everything in the article before in different places but it is very convenient to have it all in one place.

This article is VERY readable, no hard to understand language. It should be REQUIRED reading for all hams especially for Newbies who have not seen these concepts before.

Thanks for a great link Don.

Stan K9IUQ


K9IUQ2007-03-02
Benchmarks
W4LGH says: YALL HAVE WON

No one has been trying to win except perhaps you AL. *Most* of us have just been trying to get the facts out there and dispel all the myths that continue to spread about antennas.

W4LGH says : This IS the last POST by me

I shall miss you Al even tho you have continually attacked me personally. You have done much to help us understand how foolish some antenna beliefs are.

Stan K9IUQ
K6IOU2007-03-01
RE: Benchmarks
To all:

I finally found the correct URL to an excellent article on Antennas and Feedlines . . . covers most of the stuff that has been 'discussed' here lately:

http://members.dslextreme.com/users/w6wqc/antennas%20and%20feedlines.pdf

*BE SURE it is all on one line with no spaces when you copy/paste it into the address line.

DON
K6IOU
Reply to a comment by : W4LGH on 2007-03-01

KD2BD wrote..."The difference between doing this on AM vs. FM or TV is that the FM or TV antennas used in diplexed applications have HUGE bandwidths, and are therefore resonant (and impedance matched, and provide a respectable antenna pattern (gain)) for each station sharing the common antenna. " ============ Now isn't this an interesting statement out of a man who say resonance is NOT a factor. What he said in that response, is exactly what I have been saying. It applies to ALL frequencies, and NOT just the higher ones. It is all 100% the same, it resonant, therefore the impedance is matched and provides a respectable pattern! 100% Correct, and 100% the same for HAM radio. ============ You guys are really something else. There are posts saying you can use a tuner in your shack hooked to coax, and that you can tune your antenna. Again, I say you can not tune the ANTENNA, you can however match the impedance of the coax to the tuner. With an average run of 100' of RG8X, the losses are to great. I have never said you could not do this with OPEN line...as a matter of fact I said you could do this, but you still has some loss, probably more acceptable than coax. ============= KB2DB further writes..."By definition, at resonance the feedpoint impedance is 100% resistive." This statement is only true in the fact that @ resonance the feedpoint is 100% resistive, however there is a lot more to the definition of a resonant antenna. You need to go back and read about resonanace in circuits and antennas. There is a lot more to it. ============= In any event, yall have turned around what has been said, read into it either to much, and/or not enough, or totally by your own interpitation as to what you wanted it to say. Some like KB2DB, has gone as far to contradict himself. (where, read above in quotes) This IS the last POST by me. It has totally worn me out with all this cutting and pasting, he said, you said, they said, crap. Some of you have a fairly good concept of whats actually happening, some are so far off it isn't funny. Some want to argue over .1db loss which they say doesn't count, but none the less is a loss, which proves what I have been saying, whether it is .001db or 10db, it is a loss over a resonant antenna. You do it your way, and I'll do it my way. Right wrong or indifferent, I know yall can work anybody you hear! Thats about as stupid a statement as saying you always find what you are looking for the last place you look! Well you gotta be a complete idiot if you keep looking for it after you found it, so it will always be the last place you look, even if its the first place. Can work anybody I hear...same thing...how can you work them if you don't hear them? Frog hair can only be split so many times, and its way past that limit! YALL HAVE WON!! (but that doesn't make you right) de W4LGH OUT/QRT on eHam Have fun!!
Reply to a comment by : N4SL on 2007-03-01

MUST LOOK AWAY. MUST LOOK AWAY. CANNOT DO IT.
Reply to a comment by : KD2BD on 2007-03-01

W4LGH wrote: > In the case of these 2 stations in NY, you even read > that one has a STRONGER signal than the other one, > why, because the antenna (tower) is closer to its > resonance. WRONG. It has nothing to do with resonance. It has everything to do with antenna radiation PATTERN! It is the same reason a quarter-wave vertical will produce a stronger groundwave signal than a 3/4 wave vertical. Both are natural resonant lengths, but the 3/4 wave vertical produces greater radiation at higher elevation angles than does the quarter wave, thereby producing a weaker groundwave signal. Wrong again, Al. Wrong again... I'm still waiting for your "hardcore" proof that a 75-meter half-wave dipole fed with RG/8 through a well-designed tuner in the shack cannot become a resonant system on 18 MHz. Where is it? 73, de John, KD2BD
Reply to a comment by : KD2BD on 2007-03-01

N4KC wrote: > John, I wasn't very clear in my statement. I believe > what you are actually bringing to resonance with a > tuner is the antenna system, not just the antenna. > Correct me if I misspoke. After 45 years as a ham, > I'm STILL learning about antennas. So's everyone else. :-) You are correct. The combination of the tuner, the transmission line, and the radiator are brought into resonance, and the resulting impedance matched to the transmitter with proper use of the tuner, regardless of its location in the system. > Also, it is common for not only AM stations but also > broadcast FM and TV stations to use the same antenna > even though they are on very different frequencies. Correct. The difference between doing this on AM vs. FM or TV is that the FM or TV antennas used in diplexed applications have HUGE bandwidths, and are therefore resonant (and impedance matched, and provide a respectable antenna pattern (gain)) for each station sharing the common antenna. An AM tower on the other hand, is seldom more than 10 or so kHz wide in bandwidth, so the specific resonant frequencies in a diplexed AM installation must be established through LC networks in the "shack". The height of the tower in this case simply establishes the antenna's radiation pattern, not necessarily the antenna's resonant frequency. It's done MUCH more often in the FM and television world. In fact, with the advent of HDTV, many UHF broadcasters have replaced their single channel antennas (Pylons) with broadband panel arrays to be able to diplex both their analog and digital channels through a single antenna and feedline. This saves tower space, and helps to maintain equal coverage between each service. > And the diplexer is typically located at the > transmitters, on the ground, not a thousand feet > up the tower. Nor do they ever use open wire > feedline. Imagine that... :-) Some UHF broadcasters even use waveguide. :-O > Don N4KC 73, de John, KD2BD
Reply to a comment by : KD2BD on 2007-03-01

K1DA wrote: > The interesting about 660 and 880 am is that if you > live within groundwave range of them, 660 has a better > signal. They both have killer signals into Rhode Island > during the day. WFAN is stronger because the tower is slightly taller than it should be for optimum performance at 880 kHz. The antenna is a compromise in that regard. 73, de John, KD2BD
Reply to a comment by : K1DA on 2007-03-01

The interesting about 660 and 880 am is that if you live within groundwave range of them, 660 has a better signal. They both have killer signals into Rhode Island during the day.
Reply to a comment by : KD2BD on 2007-03-01

N4KC wrote: > I'm not sure anyone here has said that you can "tune > an antenna into resonance" with a "tuner." If they > did, they are incorrect. Don, actually, you CAN. It is well understood that an antenna's natural resonant frequency can easily be modified through an LC network at the feedpoint. It can ALSO be changed in the shack at the other end of the feedline using a similar network, or anywhere else in between, for that matter. Other than the additional loss incurred in the feedline, it does not matter whether the LC network (tuner) is at the feedpoint, or in the shack. The natural resonant frequency of the antenna IS MODIFIED nonetheless through the tuning network. This is what makes it possible to use a 75-meter dipole on 17 through a tuner, or a dipole cut for the phone portion of 75 on the CW portion as well. The tuner allows the antenna system's resonant frequency to be changed to our desired operating frequency without having to change its physical length. It does more than simply match impedances. Realizing a tuning network can modify a single antenna's resonant frequency makes for some VERY interesting possibilities. A pair of tuners properly diplexed into a single antenna can provide perfect resonance on two separate frequencies SIMULTANEOUSLY! That's right! Here's a "real world" example: http://www.fybush.com/site-030424.html This web page describes the operation of two radio stations, WFAN and WCBS, both 50 kW AM stations, 220 kHz apart in frequency, that operate SIMULTANEOUSLY into a single radiating tower. There is a photo toward the bottom of the page that shows a SINGLE length of coaxial transmission line feeding the combined 100 kW carrier (400 kW PEP) from both transmitters into the base of the tower. Originally, the tower included parallel-tuned "traps" toward the top (just like a ham's trap vertical antenna) to establish individual points of resonance at each radio stations' frequency. However, the current arrangement that completely eliminates the traps and instead establishes points of resonance in the antenna tuning network for each transmitter has proven to be a superior approach. 73, de John, KD2BD
Reply to a comment by : KD2BD on 2007-03-01

W4LGH wrote: > Now if you truely believe a tuner in your shack > hooked to coax, will make a 75meter dipole resonant > on 17meters, you have no idea what resonant is or > means, and I can and will gladly show you "HARDCORE > PROOF" that this is NOT so! PROOF that you can see > with your OWN eyes! I don't "believe" a tuner in your shack connected to a coax-fed dipole cut for 75 can be made to resonate on 17. I know it for a fact. A 5/8ths wave vertical isn't a "natural" resonant length for a radiator. Yet, combined with a proper resonating and impedance matching network, it can not only resonate where we want, it also provides some gain (vertical directivity) over a "naturally resonant" quarter wavelength antenna without the additional matching network. So, go ahead. Start off simple. Demonstrate your "hardcore" proof that a 75-meter half-wave dipole fed with RG/8 through a well-designed tuner in the shack cannot become a resonant system on 18 MHz. First, please begin with your definition of "resonant". And please stay away from Wikipedia this time. I want to hear YOUR definition, because as you stated earlier, textbooks are only good as a "starting point". The floor is yours. 73, de John, KD2BD
Reply to a comment by : W4LGH on 2007-02-28

KD2BD wrote..."Standing Wave antennas, on the other hand, are resonant, including operating on 17 meters with a 75 meter coax fed dipole through a tuner. Adjusting the antenna tuner in the shack for a 50 ohm resistive output impedance in this case MAKES THE 75-METER ANTENNA SYSTEM RESONANT ON 17 METERS! And you were proven otherwise. Many times." ======== I fail to see where I have been PROVEN wrong at all. No proof has been offered, other than whats been written in books, and some standard math formulas, that we all know. And I have said, they are great for a starting point. Now if you truely believe a tuner in your shack hooked to coax, will make a 75meter dipole resonant on 17meters, you have no idea what resonant is or means, and I can and will gladly show you "HARDCORE PROOF" that this is NOT so! PROOF that you can see with your OWN eyes! Now will it make it work? To some degree, by fooling your transmitter to load into the tuner, which again, you could do with a 48" whip hooked to it. You can post until you are BLUE that this is SO, and again, I will SHOW you PROOF that is is NOT! If it was SO, there would be (1)antenna manufacture that would build 1 antenna the same for everything out there and you then buy your antenna tuner and hook it up to load it. This simply isn't so, and MILLIONS of $$$ are spent every year to improve on antenna design & efficiency. I just don't understand why hams want to continue to live in the dark ages. All of what I have said is also documented and can simply be seen, just looking around. You can load your 80m dipole up on 2meters if you have enough capacitance & inductance to tune out the reactance at the end of the coax, but it doesn't make it resoanant or efficient on 2 meters. If what you and several others have been trying to make other believe, there is one (1) antenna to fit all, just plug in your tuner. NO..it doesn't work that way! And there is NO technical refferance that has ever supported that theory. Broadcaster, cell phone companys and Hams have certainly wasted lots of money going on what you are trying to say. Wake up and smell the coffee man...Stop misleading the hams on here and stop trying to make me look like a fool, neither is correct. You simply CAN NOT TUNE the resonant frequency of the antenna by changing the reactance/impedance or resistance with a tuner in your shack hooked to un-balanced coax. 73 de W4LGH - Alan http://www.w4lgh.com
Reply to a comment by : N4SL on 2007-02-28

I Like Cake.
Reply to a comment by : ONAIR on 2007-02-22

Interesting point. So a resonant vertical dipole would then be a lot more efficient than a vertical that you would need to tune?
W4LGH2007-03-01
RE: Benchmarks
KD2BD wrote..."The difference between doing this on AM vs. FM or TV is that the FM or TV antennas used in diplexed applications have HUGE bandwidths, and are therefore resonant (and impedance matched, and provide a respectable antenna pattern (gain)) for each station sharing the common antenna. "
============
Now isn't this an interesting statement out of a man who say resonance is NOT a factor. What he said in that response, is exactly what I have been saying. It applies to ALL frequencies, and NOT just the higher ones. It is all 100% the same, it resonant, therefore the impedance is matched and provides a respectable pattern! 100% Correct, and 100% the same for HAM radio.

============
You guys are really something else. There are posts saying you can use a tuner in your shack hooked to coax, and that you can tune your antenna. Again, I say you can not tune the ANTENNA, you can however match the impedance of the coax to the tuner. With an average run of 100' of RG8X, the losses are to great.
I have never said you could not do this with OPEN line...as a matter of fact I said you could do this, but you still has some loss, probably more acceptable than coax.
=============
KB2DB further writes..."By definition, at resonance the feedpoint impedance is 100% resistive." This statement is only true in the fact that @ resonance the feedpoint is 100% resistive, however there is a lot more to the definition of a resonant antenna. You need to go back and read about resonanace in circuits and antennas. There is a lot more to it.
=============

In any event, yall have turned around what has been said, read into it either to much, and/or not enough, or totally by your own interpitation as to what you wanted it to say. Some like KB2DB, has gone as far to contradict himself. (where, read above in quotes)

This IS the last POST by me. It has totally worn me out with all this cutting and pasting, he said, you said, they said, crap. Some of you have a fairly good concept of whats actually happening, some are so far off it isn't funny. Some want to argue over .1db loss which they say doesn't count, but none the less is a loss, which proves what I have been saying, whether it is .001db or 10db, it is a loss over a resonant antenna.

You do it your way, and I'll do it my way. Right wrong or indifferent, I know yall can work anybody you hear! Thats about as stupid a statement as saying you always find what you are looking for the last place you look! Well you gotta be a complete idiot if you keep looking for it after you found it, so it will always be the last place you look, even if its the first place. Can work anybody I hear...same thing...how can you work them if you don't hear them?
Frog hair can only be split so many times, and its way past that limit!

YALL HAVE WON!! (but that doesn't make you right)

de W4LGH OUT/QRT on eHam

Have fun!!





Reply to a comment by : N4SL on 2007-03-01

MUST LOOK AWAY. MUST LOOK AWAY. CANNOT DO IT.
Reply to a comment by : KD2BD on 2007-03-01

W4LGH wrote: > In the case of these 2 stations in NY, you even read > that one has a STRONGER signal than the other one, > why, because the antenna (tower) is closer to its > resonance. WRONG. It has nothing to do with resonance. It has everything to do with antenna radiation PATTERN! It is the same reason a quarter-wave vertical will produce a stronger groundwave signal than a 3/4 wave vertical. Both are natural resonant lengths, but the 3/4 wave vertical produces greater radiation at higher elevation angles than does the quarter wave, thereby producing a weaker groundwave signal. Wrong again, Al. Wrong again... I'm still waiting for your "hardcore" proof that a 75-meter half-wave dipole fed with RG/8 through a well-designed tuner in the shack cannot become a resonant system on 18 MHz. Where is it? 73, de John, KD2BD
Reply to a comment by : KD2BD on 2007-03-01

N4KC wrote: > John, I wasn't very clear in my statement. I believe > what you are actually bringing to resonance with a > tuner is the antenna system, not just the antenna. > Correct me if I misspoke. After 45 years as a ham, > I'm STILL learning about antennas. So's everyone else. :-) You are correct. The combination of the tuner, the transmission line, and the radiator are brought into resonance, and the resulting impedance matched to the transmitter with proper use of the tuner, regardless of its location in the system. > Also, it is common for not only AM stations but also > broadcast FM and TV stations to use the same antenna > even though they are on very different frequencies. Correct. The difference between doing this on AM vs. FM or TV is that the FM or TV antennas used in diplexed applications have HUGE bandwidths, and are therefore resonant (and impedance matched, and provide a respectable antenna pattern (gain)) for each station sharing the common antenna. An AM tower on the other hand, is seldom more than 10 or so kHz wide in bandwidth, so the specific resonant frequencies in a diplexed AM installation must be established through LC networks in the "shack". The height of the tower in this case simply establishes the antenna's radiation pattern, not necessarily the antenna's resonant frequency. It's done MUCH more often in the FM and television world. In fact, with the advent of HDTV, many UHF broadcasters have replaced their single channel antennas (Pylons) with broadband panel arrays to be able to diplex both their analog and digital channels through a single antenna and feedline. This saves tower space, and helps to maintain equal coverage between each service. > And the diplexer is typically located at the > transmitters, on the ground, not a thousand feet > up the tower. Nor do they ever use open wire > feedline. Imagine that... :-) Some UHF broadcasters even use waveguide. :-O > Don N4KC 73, de John, KD2BD
Reply to a comment by : KD2BD on 2007-03-01

K1DA wrote: > The interesting about 660 and 880 am is that if you > live within groundwave range of them, 660 has a better > signal. They both have killer signals into Rhode Island > during the day. WFAN is stronger because the tower is slightly taller than it should be for optimum performance at 880 kHz. The antenna is a compromise in that regard. 73, de John, KD2BD
Reply to a comment by : K1DA on 2007-03-01

The interesting about 660 and 880 am is that if you live within groundwave range of them, 660 has a better signal. They both have killer signals into Rhode Island during the day.
Reply to a comment by : KD2BD on 2007-03-01

N4KC wrote: > I'm not sure anyone here has said that you can "tune > an antenna into resonance" with a "tuner." If they > did, they are incorrect. Don, actually, you CAN. It is well understood that an antenna's natural resonant frequency can easily be modified through an LC network at the feedpoint. It can ALSO be changed in the shack at the other end of the feedline using a similar network, or anywhere else in between, for that matter. Other than the additional loss incurred in the feedline, it does not matter whether the LC network (tuner) is at the feedpoint, or in the shack. The natural resonant frequency of the antenna IS MODIFIED nonetheless through the tuning network. This is what makes it possible to use a 75-meter dipole on 17 through a tuner, or a dipole cut for the phone portion of 75 on the CW portion as well. The tuner allows the antenna system's resonant frequency to be changed to our desired operating frequency without having to change its physical length. It does more than simply match impedances. Realizing a tuning network can modify a single antenna's resonant frequency makes for some VERY interesting possibilities. A pair of tuners properly diplexed into a single antenna can provide perfect resonance on two separate frequencies SIMULTANEOUSLY! That's right! Here's a "real world" example: http://www.fybush.com/site-030424.html This web page describes the operation of two radio stations, WFAN and WCBS, both 50 kW AM stations, 220 kHz apart in frequency, that operate SIMULTANEOUSLY into a single radiating tower. There is a photo toward the bottom of the page that shows a SINGLE length of coaxial transmission line feeding the combined 100 kW carrier (400 kW PEP) from both transmitters into the base of the tower. Originally, the tower included parallel-tuned "traps" toward the top (just like a ham's trap vertical antenna) to establish individual points of resonance at each radio stations' frequency. However, the current arrangement that completely eliminates the traps and instead establishes points of resonance in the antenna tuning network for each transmitter has proven to be a superior approach. 73, de John, KD2BD
Reply to a comment by : KD2BD on 2007-03-01

W4LGH wrote: > Now if you truely believe a tuner in your shack > hooked to coax, will make a 75meter dipole resonant > on 17meters, you have no idea what resonant is or > means, and I can and will gladly show you "HARDCORE > PROOF" that this is NOT so! PROOF that you can see > with your OWN eyes! I don't "believe" a tuner in your shack connected to a coax-fed dipole cut for 75 can be made to resonate on 17. I know it for a fact. A 5/8ths wave vertical isn't a "natural" resonant length for a radiator. Yet, combined with a proper resonating and impedance matching network, it can not only resonate where we want, it also provides some gain (vertical directivity) over a "naturally resonant" quarter wavelength antenna without the additional matching network. So, go ahead. Start off simple. Demonstrate your "hardcore" proof that a 75-meter half-wave dipole fed with RG/8 through a well-designed tuner in the shack cannot become a resonant system on 18 MHz. First, please begin with your definition of "resonant". And please stay away from Wikipedia this time. I want to hear YOUR definition, because as you stated earlier, textbooks are only good as a "starting point". The floor is yours. 73, de John, KD2BD
Reply to a comment by : W4LGH on 2007-02-28

KD2BD wrote..."Standing Wave antennas, on the other hand, are resonant, including operating on 17 meters with a 75 meter coax fed dipole through a tuner. Adjusting the antenna tuner in the shack for a 50 ohm resistive output impedance in this case MAKES THE 75-METER ANTENNA SYSTEM RESONANT ON 17 METERS! And you were proven otherwise. Many times." ======== I fail to see where I have been PROVEN wrong at all. No proof has been offered, other than whats been written in books, and some standard math formulas, that we all know. And I have said, they are great for a starting point. Now if you truely believe a tuner in your shack hooked to coax, will make a 75meter dipole resonant on 17meters, you have no idea what resonant is or means, and I can and will gladly show you "HARDCORE PROOF" that this is NOT so! PROOF that you can see with your OWN eyes! Now will it make it work? To some degree, by fooling your transmitter to load into the tuner, which again, you could do with a 48" whip hooked to it. You can post until you are BLUE that this is SO, and again, I will SHOW you PROOF that is is NOT! If it was SO, there would be (1)antenna manufacture that would build 1 antenna the same for everything out there and you then buy your antenna tuner and hook it up to load it. This simply isn't so, and MILLIONS of $$$ are spent every year to improve on antenna design & efficiency. I just don't understand why hams want to continue to live in the dark ages. All of what I have said is also documented and can simply be seen, just looking around. You can load your 80m dipole up on 2meters if you have enough capacitance & inductance to tune out the reactance at the end of the coax, but it doesn't make it resoanant or efficient on 2 meters. If what you and several others have been trying to make other believe, there is one (1) antenna to fit all, just plug in your tuner. NO..it doesn't work that way! And there is NO technical refferance that has ever supported that theory. Broadcaster, cell phone companys and Hams have certainly wasted lots of money going on what you are trying to say. Wake up and smell the coffee man...Stop misleading the hams on here and stop trying to make me look like a fool, neither is correct. You simply CAN NOT TUNE the resonant frequency of the antenna by changing the reactance/impedance or resistance with a tuner in your shack hooked to un-balanced coax. 73 de W4LGH - Alan http://www.w4lgh.com
Reply to a comment by : N4SL on 2007-02-28

I Like Cake.
Reply to a comment by : ONAIR on 2007-02-22

Interesting point. So a resonant vertical dipole would then be a lot more efficient than a vertical that you would need to tune?
KD2BD2007-03-01
RE: Benchmarks
W4LGH wrote:

> You are digging at straws there bud. A signal tower
> fed with 2 transmitters will have the exact radiation
> pattern. Its the same antenna being fed as a 1/4wave
> vertical (or so it thinks it is with teh matching
> network)

No. The antenna isn't "thinking".

The antenna possesses two different electrical lengths (in terms of wavelength) at each operating frequency, thereby producing slightly different radiation patterns at each frequency. The tower is a little too tall for the higher of the two frequencies.

The tuning arrangement in the transmitter building establishes resonance at each frequency, but the tuner CANNOT modify the radiation pattern of the tower at either frequency.

> The Antenna System ,thru the magic of the diplexer,
> is being matched to both frequencies,

As I started earlier, this isn't about MAGIC. It's about science. There's a difference. A big one. Magic implies a lack of understanding about how something works.

> The xmitters thinks(fooled)they are hooked to a
> resonant load

The transmitters aren't "thinking" either, nor are they being "fooled". Each sees a resonant load its operating frequency, and the tower radiates all the RF from both transmitters.

> Measure each in the shack, measure each at the
> antenna, and see the difference. We will then do
> the same thing using a field strength meter and
> look at the effective radiation patters, and
> signals.

Radiation patterns have nothing to do with RESONANCE. A Beverage antenna has a radiation pattern and is non-resonant.

How do you define resonance, Al?


73, de John, KD2BD
Reply to a comment by : KD2BD on 2007-03-01

W4LGH wrote: > In the case of these 2 stations in NY, you even read > that one has a STRONGER signal than the other one, > why, because the antenna (tower) is closer to its > resonance. WRONG. It has nothing to do with resonance. It has everything to do with antenna radiation PATTERN! It is the same reason a quarter-wave vertical will produce a stronger groundwave signal than a 3/4 wave vertical. Both are natural resonant lengths, but the 3/4 wave vertical produces greater radiation at higher elevation angles than does the quarter wave, thereby producing a weaker groundwave signal. Wrong again, Al. Wrong again... I'm still waiting for your "hardcore" proof that a 75-meter half-wave dipole fed with RG/8 through a well-designed tuner in the shack cannot become a resonant system on 18 MHz. Where is it? 73, de John, KD2BD
Reply to a comment by : KD2BD on 2007-03-01

N4KC wrote: > John, I wasn't very clear in my statement. I believe > what you are actually bringing to resonance with a > tuner is the antenna system, not just the antenna. > Correct me if I misspoke. After 45 years as a ham, > I'm STILL learning about antennas. So's everyone else. :-) You are correct. The combination of the tuner, the transmission line, and the radiator are brought into resonance, and the resulting impedance matched to the transmitter with proper use of the tuner, regardless of its location in the system. > Also, it is common for not only AM stations but also > broadcast FM and TV stations to use the same antenna > even though they are on very different frequencies. Correct. The difference between doing this on AM vs. FM or TV is that the FM or TV antennas used in diplexed applications have HUGE bandwidths, and are therefore resonant (and impedance matched, and provide a respectable antenna pattern (gain)) for each station sharing the common antenna. An AM tower on the other hand, is seldom more than 10 or so kHz wide in bandwidth, so the specific resonant frequencies in a diplexed AM installation must be established through LC networks in the "shack". The height of the tower in this case simply establishes the antenna's radiation pattern, not necessarily the antenna's resonant frequency. It's done MUCH more often in the FM and television world. In fact, with the advent of HDTV, many UHF broadcasters have replaced their single channel antennas (Pylons) with broadband panel arrays to be able to diplex both their analog and digital channels through a single antenna and feedline. This saves tower space, and helps to maintain equal coverage between each service. > And the diplexer is typically located at the > transmitters, on the ground, not a thousand feet > up the tower. Nor do they ever use open wire > feedline. Imagine that... :-) Some UHF broadcasters even use waveguide. :-O > Don N4KC 73, de John, KD2BD
Reply to a comment by : KD2BD on 2007-03-01

K1DA wrote: > The interesting about 660 and 880 am is that if you > live within groundwave range of them, 660 has a better > signal. They both have killer signals into Rhode Island > during the day. WFAN is stronger because the tower is slightly taller than it should be for optimum performance at 880 kHz. The antenna is a compromise in that regard. 73, de John, KD2BD
Reply to a comment by : K1DA on 2007-03-01

The interesting about 660 and 880 am is that if you live within groundwave range of them, 660 has a better signal. They both have killer signals into Rhode Island during the day.
Reply to a comment by : KD2BD on 2007-03-01

N4KC wrote: > I'm not sure anyone here has said that you can "tune > an antenna into resonance" with a "tuner." If they > did, they are incorrect. Don, actually, you CAN. It is well understood that an antenna's natural resonant frequency can easily be modified through an LC network at the feedpoint. It can ALSO be changed in the shack at the other end of the feedline using a similar network, or anywhere else in between, for that matter. Other than the additional loss incurred in the feedline, it does not matter whether the LC network (tuner) is at the feedpoint, or in the shack. The natural resonant frequency of the antenna IS MODIFIED nonetheless through the tuning network. This is what makes it possible to use a 75-meter dipole on 17 through a tuner, or a dipole cut for the phone portion of 75 on the CW portion as well. The tuner allows the antenna system's resonant frequency to be changed to our desired operating frequency without having to change its physical length. It does more than simply match impedances. Realizing a tuning network can modify a single antenna's resonant frequency makes for some VERY interesting possibilities. A pair of tuners properly diplexed into a single antenna can provide perfect resonance on two separate frequencies SIMULTANEOUSLY! That's right! Here's a "real world" example: http://www.fybush.com/site-030424.html This web page describes the operation of two radio stations, WFAN and WCBS, both 50 kW AM stations, 220 kHz apart in frequency, that operate SIMULTANEOUSLY into a single radiating tower. There is a photo toward the bottom of the page that shows a SINGLE length of coaxial transmission line feeding the combined 100 kW carrier (400 kW PEP) from both transmitters into the base of the tower. Originally, the tower included parallel-tuned "traps" toward the top (just like a ham's trap vertical antenna) to establish individual points of resonance at each radio stations' frequency. However, the current arrangement that completely eliminates the traps and instead establishes points of resonance in the antenna tuning network for each transmitter has proven to be a superior approach. 73, de John, KD2BD
Reply to a comment by : KD2BD on 2007-03-01

W4LGH wrote: > Now if you truely believe a tuner in your shack > hooked to coax, will make a 75meter dipole resonant > on 17meters, you have no idea what resonant is or > means, and I can and will gladly show you "HARDCORE > PROOF" that this is NOT so! PROOF that you can see > with your OWN eyes! I don't "believe" a tuner in your shack connected to a coax-fed dipole cut for 75 can be made to resonate on 17. I know it for a fact. A 5/8ths wave vertical isn't a "natural" resonant length for a radiator. Yet, combined with a proper resonating and impedance matching network, it can not only resonate where we want, it also provides some gain (vertical directivity) over a "naturally resonant" quarter wavelength antenna without the additional matching network. So, go ahead. Start off simple. Demonstrate your "hardcore" proof that a 75-meter half-wave dipole fed with RG/8 through a well-designed tuner in the shack cannot become a resonant system on 18 MHz. First, please begin with your definition of "resonant". And please stay away from Wikipedia this time. I want to hear YOUR definition, because as you stated earlier, textbooks are only good as a "starting point". The floor is yours. 73, de John, KD2BD
Reply to a comment by : W4LGH on 2007-02-28

KD2BD wrote..."Standing Wave antennas, on the other hand, are resonant, including operating on 17 meters with a 75 meter coax fed dipole through a tuner. Adjusting the antenna tuner in the shack for a 50 ohm resistive output impedance in this case MAKES THE 75-METER ANTENNA SYSTEM RESONANT ON 17 METERS! And you were proven otherwise. Many times." ======== I fail to see where I have been PROVEN wrong at all. No proof has been offered, other than whats been written in books, and some standard math formulas, that we all know. And I have said, they are great for a starting point. Now if you truely believe a tuner in your shack hooked to coax, will make a 75meter dipole resonant on 17meters, you have no idea what resonant is or means, and I can and will gladly show you "HARDCORE PROOF" that this is NOT so! PROOF that you can see with your OWN eyes! Now will it make it work? To some degree, by fooling your transmitter to load into the tuner, which again, you could do with a 48" whip hooked to it. You can post until you are BLUE that this is SO, and again, I will SHOW you PROOF that is is NOT! If it was SO, there would be (1)antenna manufacture that would build 1 antenna the same for everything out there and you then buy your antenna tuner and hook it up to load it. This simply isn't so, and MILLIONS of $$$ are spent every year to improve on antenna design & efficiency. I just don't understand why hams want to continue to live in the dark ages. All of what I have said is also documented and can simply be seen, just looking around. You can load your 80m dipole up on 2meters if you have enough capacitance & inductance to tune out the reactance at the end of the coax, but it doesn't make it resoanant or efficient on 2 meters. If what you and several others have been trying to make other believe, there is one (1) antenna to fit all, just plug in your tuner. NO..it doesn't work that way! And there is NO technical refferance that has ever supported that theory. Broadcaster, cell phone companys and Hams have certainly wasted lots of money going on what you are trying to say. Wake up and smell the coffee man...Stop misleading the hams on here and stop trying to make me look like a fool, neither is correct. You simply CAN NOT TUNE the resonant frequency of the antenna by changing the reactance/impedance or resistance with a tuner in your shack hooked to un-balanced coax. 73 de W4LGH - Alan http://www.w4lgh.com
Reply to a comment by : N4SL on 2007-02-28

I Like Cake.
Reply to a comment by : ONAIR on 2007-02-22

Interesting point. So a resonant vertical dipole would then be a lot more efficient than a vertical that you would need to tune?
N4SL2007-03-01
RE: Benchmarks
MUST LOOK AWAY.
MUST LOOK AWAY.
CANNOT DO IT.
Reply to a comment by : KD2BD on 2007-03-01

W4LGH wrote: > In the case of these 2 stations in NY, you even read > that one has a STRONGER signal than the other one, > why, because the antenna (tower) is closer to its > resonance. WRONG. It has nothing to do with resonance. It has everything to do with antenna radiation PATTERN! It is the same reason a quarter-wave vertical will produce a stronger groundwave signal than a 3/4 wave vertical. Both are natural resonant lengths, but the 3/4 wave vertical produces greater radiation at higher elevation angles than does the quarter wave, thereby producing a weaker groundwave signal. Wrong again, Al. Wrong again... I'm still waiting for your "hardcore" proof that a 75-meter half-wave dipole fed with RG/8 through a well-designed tuner in the shack cannot become a resonant system on 18 MHz. Where is it? 73, de John, KD2BD
Reply to a comment by : KD2BD on 2007-03-01

N4KC wrote: > John, I wasn't very clear in my statement. I believe > what you are actually bringing to resonance with a > tuner is the antenna system, not just the antenna. > Correct me if I misspoke. After 45 years as a ham, > I'm STILL learning about antennas. So's everyone else. :-) You are correct. The combination of the tuner, the transmission line, and the radiator are brought into resonance, and the resulting impedance matched to the transmitter with proper use of the tuner, regardless of its location in the system. > Also, it is common for not only AM stations but also > broadcast FM and TV stations to use the same antenna > even though they are on very different frequencies. Correct. The difference between doing this on AM vs. FM or TV is that the FM or TV antennas used in diplexed applications have HUGE bandwidths, and are therefore resonant (and impedance matched, and provide a respectable antenna pattern (gain)) for each station sharing the common antenna. An AM tower on the other hand, is seldom more than 10 or so kHz wide in bandwidth, so the specific resonant frequencies in a diplexed AM installation must be established through LC networks in the "shack". The height of the tower in this case simply establishes the antenna's radiation pattern, not necessarily the antenna's resonant frequency. It's done MUCH more often in the FM and television world. In fact, with the advent of HDTV, many UHF broadcasters have replaced their single channel antennas (Pylons) with broadband panel arrays to be able to diplex both their analog and digital channels through a single antenna and feedline. This saves tower space, and helps to maintain equal coverage between each service. > And the diplexer is typically located at the > transmitters, on the ground, not a thousand feet > up the tower. Nor do they ever use open wire > feedline. Imagine that... :-) Some UHF broadcasters even use waveguide. :-O > Don N4KC 73, de John, KD2BD
Reply to a comment by : KD2BD on 2007-03-01

K1DA wrote: > The interesting about 660 and 880 am is that if you > live within groundwave range of them, 660 has a better > signal. They both have killer signals into Rhode Island > during the day. WFAN is stronger because the tower is slightly taller than it should be for optimum performance at 880 kHz. The antenna is a compromise in that regard. 73, de John, KD2BD
Reply to a comment by : K1DA on 2007-03-01

The interesting about 660 and 880 am is that if you live within groundwave range of them, 660 has a better signal. They both have killer signals into Rhode Island during the day.
Reply to a comment by : KD2BD on 2007-03-01

N4KC wrote: > I'm not sure anyone here has said that you can "tune > an antenna into resonance" with a "tuner." If they > did, they are incorrect. Don, actually, you CAN. It is well understood that an antenna's natural resonant frequency can easily be modified through an LC network at the feedpoint. It can ALSO be changed in the shack at the other end of the feedline using a similar network, or anywhere else in between, for that matter. Other than the additional loss incurred in the feedline, it does not matter whether the LC network (tuner) is at the feedpoint, or in the shack. The natural resonant frequency of the antenna IS MODIFIED nonetheless through the tuning network. This is what makes it possible to use a 75-meter dipole on 17 through a tuner, or a dipole cut for the phone portion of 75 on the CW portion as well. The tuner allows the antenna system's resonant frequency to be changed to our desired operating frequency without having to change its physical length. It does more than simply match impedances. Realizing a tuning network can modify a single antenna's resonant frequency makes for some VERY interesting possibilities. A pair of tuners properly diplexed into a single antenna can provide perfect resonance on two separate frequencies SIMULTANEOUSLY! That's right! Here's a "real world" example: http://www.fybush.com/site-030424.html This web page describes the operation of two radio stations, WFAN and WCBS, both 50 kW AM stations, 220 kHz apart in frequency, that operate SIMULTANEOUSLY into a single radiating tower. There is a photo toward the bottom of the page that shows a SINGLE length of coaxial transmission line feeding the combined 100 kW carrier (400 kW PEP) from both transmitters into the base of the tower. Originally, the tower included parallel-tuned "traps" toward the top (just like a ham's trap vertical antenna) to establish individual points of resonance at each radio stations' frequency. However, the current arrangement that completely eliminates the traps and instead establishes points of resonance in the antenna tuning network for each transmitter has proven to be a superior approach. 73, de John, KD2BD
Reply to a comment by : KD2BD on 2007-03-01

W4LGH wrote: > Now if you truely believe a tuner in your shack > hooked to coax, will make a 75meter dipole resonant > on 17meters, you have no idea what resonant is or > means, and I can and will gladly show you "HARDCORE > PROOF" that this is NOT so! PROOF that you can see > with your OWN eyes! I don't "believe" a tuner in your shack connected to a coax-fed dipole cut for 75 can be made to resonate on 17. I know it for a fact. A 5/8ths wave vertical isn't a "natural" resonant length for a radiator. Yet, combined with a proper resonating and impedance matching network, it can not only resonate where we want, it also provides some gain (vertical directivity) over a "naturally resonant" quarter wavelength antenna without the additional matching network. So, go ahead. Start off simple. Demonstrate your "hardcore" proof that a 75-meter half-wave dipole fed with RG/8 through a well-designed tuner in the shack cannot become a resonant system on 18 MHz. First, please begin with your definition of "resonant". And please stay away from Wikipedia this time. I want to hear YOUR definition, because as you stated earlier, textbooks are only good as a "starting point". The floor is yours. 73, de John, KD2BD
Reply to a comment by : W4LGH on 2007-02-28

KD2BD wrote..."Standing Wave antennas, on the other hand, are resonant, including operating on 17 meters with a 75 meter coax fed dipole through a tuner. Adjusting the antenna tuner in the shack for a 50 ohm resistive output impedance in this case MAKES THE 75-METER ANTENNA SYSTEM RESONANT ON 17 METERS! And you were proven otherwise. Many times." ======== I fail to see where I have been PROVEN wrong at all. No proof has been offered, other than whats been written in books, and some standard math formulas, that we all know. And I have said, they are great for a starting point. Now if you truely believe a tuner in your shack hooked to coax, will make a 75meter dipole resonant on 17meters, you have no idea what resonant is or means, and I can and will gladly show you "HARDCORE PROOF" that this is NOT so! PROOF that you can see with your OWN eyes! Now will it make it work? To some degree, by fooling your transmitter to load into the tuner, which again, you could do with a 48" whip hooked to it. You can post until you are BLUE that this is SO, and again, I will SHOW you PROOF that is is NOT! If it was SO, there would be (1)antenna manufacture that would build 1 antenna the same for everything out there and you then buy your antenna tuner and hook it up to load it. This simply isn't so, and MILLIONS of $$$ are spent every year to improve on antenna design & efficiency. I just don't understand why hams want to continue to live in the dark ages. All of what I have said is also documented and can simply be seen, just looking around. You can load your 80m dipole up on 2meters if you have enough capacitance & inductance to tune out the reactance at the end of the coax, but it doesn't make it resoanant or efficient on 2 meters. If what you and several others have been trying to make other believe, there is one (1) antenna to fit all, just plug in your tuner. NO..it doesn't work that way! And there is NO technical refferance that has ever supported that theory. Broadcaster, cell phone companys and Hams have certainly wasted lots of money going on what you are trying to say. Wake up and smell the coffee man...Stop misleading the hams on here and stop trying to make me look like a fool, neither is correct. You simply CAN NOT TUNE the resonant frequency of the antenna by changing the reactance/impedance or resistance with a tuner in your shack hooked to un-balanced coax. 73 de W4LGH - Alan http://www.w4lgh.com
Reply to a comment by : N4SL on 2007-02-28

I Like Cake.
Reply to a comment by : ONAIR on 2007-02-22

Interesting point. So a resonant vertical dipole would then be a lot more efficient than a vertical that you would need to tune?
W4LGH2007-03-01
RE: Benchmarks
KD2BD writes.."WRONG. It has nothing to do with resonance. It has everything to do with antenna radiation PATTERN!"
=======
You are digging at straws there bud. A signal tower fed with 2 transmitters will have the exact radiation pattern. Its the same antenna being fed as a 1/4wave vertical (or so it thinks it is with teh matching network) The tower is closer to resonance on one frequency than it is to the other, they should have changed the length to be in the middle of the 2 frequencies, then the resonance would be the same from the matching network.

Now if they had 2 towers on this little island then they would affect the radiation pattern dramaticly!
This is probably why they do NOT have 2 seperate antennas.

KD2BD continues..."I'm still waiting for your "hardcore" proof that a 75-meter half-wave dipole fed with RG/8 through a well-designed tuner in the shack cannot become a resonant system on 18 MHz.
Where is it?
============
Get in your car, plane, train or bis and come on down. I will supply the meters, or you can. I have 50 acres out back, and we'll put up your 75m wire, feed it with RG8 and hook it to the tuner of your choice in the shack. We'll also put up a wire cut to 17m feed with the same rg8 coax, no tuner and we will transmit the exact same power levels. Measure each in the shack, measure each at the antenna, and see the difference. We will then do the same thing using a field strength meter and look at the effective radiation patters, and signals. At this point you will see higher levels of radiation off the 17m dipole when operated @ it resonate frequency. You will also see a more predicted radiation pattern off the resonant antenna. Whenever you want to do it. Bring CASH money too, cause I am going to take it away from you. Or..you are welcome to do this at your location, as I already know what the out come is going to be, have done it many times. And I'll even take your word for it, as I think once you SEE it for yourself you will be big enough to admit it.

de W4LGH
http://www.w4lgh.com

Reply to a comment by : KD2BD on 2007-03-01

W4LGH wrote: > In the case of these 2 stations in NY, you even read > that one has a STRONGER signal than the other one, > why, because the antenna (tower) is closer to its > resonance. WRONG. It has nothing to do with resonance. It has everything to do with antenna radiation PATTERN! It is the same reason a quarter-wave vertical will produce a stronger groundwave signal than a 3/4 wave vertical. Both are natural resonant lengths, but the 3/4 wave vertical produces greater radiation at higher elevation angles than does the quarter wave, thereby producing a weaker groundwave signal. Wrong again, Al. Wrong again... I'm still waiting for your "hardcore" proof that a 75-meter half-wave dipole fed with RG/8 through a well-designed tuner in the shack cannot become a resonant system on 18 MHz. Where is it? 73, de John, KD2BD
Reply to a comment by : KD2BD on 2007-03-01

N4KC wrote: > John, I wasn't very clear in my statement. I believe > what you are actually bringing to resonance with a > tuner is the antenna system, not just the antenna. > Correct me if I misspoke. After 45 years as a ham, > I'm STILL learning about antennas. So's everyone else. :-) You are correct. The combination of the tuner, the transmission line, and the radiator are brought into resonance, and the resulting impedance matched to the transmitter with proper use of the tuner, regardless of its location in the system. > Also, it is common for not only AM stations but also > broadcast FM and TV stations to use the same antenna > even though they are on very different frequencies. Correct. The difference between doing this on AM vs. FM or TV is that the FM or TV antennas used in diplexed applications have HUGE bandwidths, and are therefore resonant (and impedance matched, and provide a respectable antenna pattern (gain)) for each station sharing the common antenna. An AM tower on the other hand, is seldom more than 10 or so kHz wide in bandwidth, so the specific resonant frequencies in a diplexed AM installation must be established through LC networks in the "shack". The height of the tower in this case simply establishes the antenna's radiation pattern, not necessarily the antenna's resonant frequency. It's done MUCH more often in the FM and television world. In fact, with the advent of HDTV, many UHF broadcasters have replaced their single channel antennas (Pylons) with broadband panel arrays to be able to diplex both their analog and digital channels through a single antenna and feedline. This saves tower space, and helps to maintain equal coverage between each service. > And the diplexer is typically located at the > transmitters, on the ground, not a thousand feet > up the tower. Nor do they ever use open wire > feedline. Imagine that... :-) Some UHF broadcasters even use waveguide. :-O > Don N4KC 73, de John, KD2BD
Reply to a comment by : KD2BD on 2007-03-01

K1DA wrote: > The interesting about 660 and 880 am is that if you > live within groundwave range of them, 660 has a better > signal. They both have killer signals into Rhode Island > during the day. WFAN is stronger because the tower is slightly taller than it should be for optimum performance at 880 kHz. The antenna is a compromise in that regard. 73, de John, KD2BD
Reply to a comment by : K1DA on 2007-03-01

The interesting about 660 and 880 am is that if you live within groundwave range of them, 660 has a better signal. They both have killer signals into Rhode Island during the day.
Reply to a comment by : KD2BD on 2007-03-01

N4KC wrote: > I'm not sure anyone here has said that you can "tune > an antenna into resonance" with a "tuner." If they > did, they are incorrect. Don, actually, you CAN. It is well understood that an antenna's natural resonant frequency can easily be modified through an LC network at the feedpoint. It can ALSO be changed in the shack at the other end of the feedline using a similar network, or anywhere else in between, for that matter. Other than the additional loss incurred in the feedline, it does not matter whether the LC network (tuner) is at the feedpoint, or in the shack. The natural resonant frequency of the antenna IS MODIFIED nonetheless through the tuning network. This is what makes it possible to use a 75-meter dipole on 17 through a tuner, or a dipole cut for the phone portion of 75 on the CW portion as well. The tuner allows the antenna system's resonant frequency to be changed to our desired operating frequency without having to change its physical length. It does more than simply match impedances. Realizing a tuning network can modify a single antenna's resonant frequency makes for some VERY interesting possibilities. A pair of tuners properly diplexed into a single antenna can provide perfect resonance on two separate frequencies SIMULTANEOUSLY! That's right! Here's a "real world" example: http://www.fybush.com/site-030424.html This web page describes the operation of two radio stations, WFAN and WCBS, both 50 kW AM stations, 220 kHz apart in frequency, that operate SIMULTANEOUSLY into a single radiating tower. There is a photo toward the bottom of the page that shows a SINGLE length of coaxial transmission line feeding the combined 100 kW carrier (400 kW PEP) from both transmitters into the base of the tower. Originally, the tower included parallel-tuned "traps" toward the top (just like a ham's trap vertical antenna) to establish individual points of resonance at each radio stations' frequency. However, the current arrangement that completely eliminates the traps and instead establishes points of resonance in the antenna tuning network for each transmitter has proven to be a superior approach. 73, de John, KD2BD
Reply to a comment by : KD2BD on 2007-03-01

W4LGH wrote: > Now if you truely believe a tuner in your shack > hooked to coax, will make a 75meter dipole resonant > on 17meters, you have no idea what resonant is or > means, and I can and will gladly show you "HARDCORE > PROOF" that this is NOT so! PROOF that you can see > with your OWN eyes! I don't "believe" a tuner in your shack connected to a coax-fed dipole cut for 75 can be made to resonate on 17. I know it for a fact. A 5/8ths wave vertical isn't a "natural" resonant length for a radiator. Yet, combined with a proper resonating and impedance matching network, it can not only resonate where we want, it also provides some gain (vertical directivity) over a "naturally resonant" quarter wavelength antenna without the additional matching network. So, go ahead. Start off simple. Demonstrate your "hardcore" proof that a 75-meter half-wave dipole fed with RG/8 through a well-designed tuner in the shack cannot become a resonant system on 18 MHz. First, please begin with your definition of "resonant". And please stay away from Wikipedia this time. I want to hear YOUR definition, because as you stated earlier, textbooks are only good as a "starting point". The floor is yours. 73, de John, KD2BD
Reply to a comment by : W4LGH on 2007-02-28

KD2BD wrote..."Standing Wave antennas, on the other hand, are resonant, including operating on 17 meters with a 75 meter coax fed dipole through a tuner. Adjusting the antenna tuner in the shack for a 50 ohm resistive output impedance in this case MAKES THE 75-METER ANTENNA SYSTEM RESONANT ON 17 METERS! And you were proven otherwise. Many times." ======== I fail to see where I have been PROVEN wrong at all. No proof has been offered, other than whats been written in books, and some standard math formulas, that we all know. And I have said, they are great for a starting point. Now if you truely believe a tuner in your shack hooked to coax, will make a 75meter dipole resonant on 17meters, you have no idea what resonant is or means, and I can and will gladly show you "HARDCORE PROOF" that this is NOT so! PROOF that you can see with your OWN eyes! Now will it make it work? To some degree, by fooling your transmitter to load into the tuner, which again, you could do with a 48" whip hooked to it. You can post until you are BLUE that this is SO, and again, I will SHOW you PROOF that is is NOT! If it was SO, there would be (1)antenna manufacture that would build 1 antenna the same for everything out there and you then buy your antenna tuner and hook it up to load it. This simply isn't so, and MILLIONS of $$$ are spent every year to improve on antenna design & efficiency. I just don't understand why hams want to continue to live in the dark ages. All of what I have said is also documented and can simply be seen, just looking around. You can load your 80m dipole up on 2meters if you have enough capacitance & inductance to tune out the reactance at the end of the coax, but it doesn't make it resoanant or efficient on 2 meters. If what you and several others have been trying to make other believe, there is one (1) antenna to fit all, just plug in your tuner. NO..it doesn't work that way! And there is NO technical refferance that has ever supported that theory. Broadcaster, cell phone companys and Hams have certainly wasted lots of money going on what you are trying to say. Wake up and smell the coffee man...Stop misleading the hams on here and stop trying to make me look like a fool, neither is correct. You simply CAN NOT TUNE the resonant frequency of the antenna by changing the reactance/impedance or resistance with a tuner in your shack hooked to un-balanced coax. 73 de W4LGH - Alan http://www.w4lgh.com
Reply to a comment by : N4SL on 2007-02-28

I Like Cake.
Reply to a comment by : ONAIR on 2007-02-22

Interesting point. So a resonant vertical dipole would then be a lot more efficient than a vertical that you would need to tune?
KD2BD2007-03-01
RE: Benchmarks
W4LGH wrote:

> In the case of these 2 stations in NY, you even read
> that one has a STRONGER signal than the other one,
> why, because the antenna (tower) is closer to its
> resonance.

WRONG. It has nothing to do with resonance. It has everything to do with antenna radiation PATTERN!

It is the same reason a quarter-wave vertical will produce a stronger groundwave signal than a 3/4 wave vertical.

Both are natural resonant lengths, but the 3/4 wave vertical produces greater radiation at higher elevation angles than does the quarter wave, thereby producing a weaker groundwave signal.

Wrong again, Al. Wrong again...

I'm still waiting for your "hardcore" proof that a 75-meter half-wave dipole fed with RG/8 through a well-designed tuner in the shack cannot become a resonant system on 18 MHz.

Where is it?


73, de John, KD2BD
Reply to a comment by : KD2BD on 2007-03-01

N4KC wrote: > John, I wasn't very clear in my statement. I believe > what you are actually bringing to resonance with a > tuner is the antenna system, not just the antenna. > Correct me if I misspoke. After 45 years as a ham, > I'm STILL learning about antennas. So's everyone else. :-) You are correct. The combination of the tuner, the transmission line, and the radiator are brought into resonance, and the resulting impedance matched to the transmitter with proper use of the tuner, regardless of its location in the system. > Also, it is common for not only AM stations but also > broadcast FM and TV stations to use the same antenna > even though they are on very different frequencies. Correct. The difference between doing this on AM vs. FM or TV is that the FM or TV antennas used in diplexed applications have HUGE bandwidths, and are therefore resonant (and impedance matched, and provide a respectable antenna pattern (gain)) for each station sharing the common antenna. An AM tower on the other hand, is seldom more than 10 or so kHz wide in bandwidth, so the specific resonant frequencies in a diplexed AM installation must be established through LC networks in the "shack". The height of the tower in this case simply establishes the antenna's radiation pattern, not necessarily the antenna's resonant frequency. It's done MUCH more often in the FM and television world. In fact, with the advent of HDTV, many UHF broadcasters have replaced their single channel antennas (Pylons) with broadband panel arrays to be able to diplex both their analog and digital channels through a single antenna and feedline. This saves tower space, and helps to maintain equal coverage between each service. > And the diplexer is typically located at the > transmitters, on the ground, not a thousand feet > up the tower. Nor do they ever use open wire > feedline. Imagine that... :-) Some UHF broadcasters even use waveguide. :-O > Don N4KC 73, de John, KD2BD
Reply to a comment by : KD2BD on 2007-03-01

K1DA wrote: > The interesting about 660 and 880 am is that if you > live within groundwave range of them, 660 has a better > signal. They both have killer signals into Rhode Island > during the day. WFAN is stronger because the tower is slightly taller than it should be for optimum performance at 880 kHz. The antenna is a compromise in that regard. 73, de John, KD2BD
Reply to a comment by : K1DA on 2007-03-01

The interesting about 660 and 880 am is that if you live within groundwave range of them, 660 has a better signal. They both have killer signals into Rhode Island during the day.
Reply to a comment by : KD2BD on 2007-03-01

N4KC wrote: > I'm not sure anyone here has said that you can "tune > an antenna into resonance" with a "tuner." If they > did, they are incorrect. Don, actually, you CAN. It is well understood that an antenna's natural resonant frequency can easily be modified through an LC network at the feedpoint. It can ALSO be changed in the shack at the other end of the feedline using a similar network, or anywhere else in between, for that matter. Other than the additional loss incurred in the feedline, it does not matter whether the LC network (tuner) is at the feedpoint, or in the shack. The natural resonant frequency of the antenna IS MODIFIED nonetheless through the tuning network. This is what makes it possible to use a 75-meter dipole on 17 through a tuner, or a dipole cut for the phone portion of 75 on the CW portion as well. The tuner allows the antenna system's resonant frequency to be changed to our desired operating frequency without having to change its physical length. It does more than simply match impedances. Realizing a tuning network can modify a single antenna's resonant frequency makes for some VERY interesting possibilities. A pair of tuners properly diplexed into a single antenna can provide perfect resonance on two separate frequencies SIMULTANEOUSLY! That's right! Here's a "real world" example: http://www.fybush.com/site-030424.html This web page describes the operation of two radio stations, WFAN and WCBS, both 50 kW AM stations, 220 kHz apart in frequency, that operate SIMULTANEOUSLY into a single radiating tower. There is a photo toward the bottom of the page that shows a SINGLE length of coaxial transmission line feeding the combined 100 kW carrier (400 kW PEP) from both transmitters into the base of the tower. Originally, the tower included parallel-tuned "traps" toward the top (just like a ham's trap vertical antenna) to establish individual points of resonance at each radio stations' frequency. However, the current arrangement that completely eliminates the traps and instead establishes points of resonance in the antenna tuning network for each transmitter has proven to be a superior approach. 73, de John, KD2BD
Reply to a comment by : KD2BD on 2007-03-01

W4LGH wrote: > Now if you truely believe a tuner in your shack > hooked to coax, will make a 75meter dipole resonant > on 17meters, you have no idea what resonant is or > means, and I can and will gladly show you "HARDCORE > PROOF" that this is NOT so! PROOF that you can see > with your OWN eyes! I don't "believe" a tuner in your shack connected to a coax-fed dipole cut for 75 can be made to resonate on 17. I know it for a fact. A 5/8ths wave vertical isn't a "natural" resonant length for a radiator. Yet, combined with a proper resonating and impedance matching network, it can not only resonate where we want, it also provides some gain (vertical directivity) over a "naturally resonant" quarter wavelength antenna without the additional matching network. So, go ahead. Start off simple. Demonstrate your "hardcore" proof that a 75-meter half-wave dipole fed with RG/8 through a well-designed tuner in the shack cannot become a resonant system on 18 MHz. First, please begin with your definition of "resonant". And please stay away from Wikipedia this time. I want to hear YOUR definition, because as you stated earlier, textbooks are only good as a "starting point". The floor is yours. 73, de John, KD2BD
Reply to a comment by : W4LGH on 2007-02-28

KD2BD wrote..."Standing Wave antennas, on the other hand, are resonant, including operating on 17 meters with a 75 meter coax fed dipole through a tuner. Adjusting the antenna tuner in the shack for a 50 ohm resistive output impedance in this case MAKES THE 75-METER ANTENNA SYSTEM RESONANT ON 17 METERS! And you were proven otherwise. Many times." ======== I fail to see where I have been PROVEN wrong at all. No proof has been offered, other than whats been written in books, and some standard math formulas, that we all know. And I have said, they are great for a starting point. Now if you truely believe a tuner in your shack hooked to coax, will make a 75meter dipole resonant on 17meters, you have no idea what resonant is or means, and I can and will gladly show you "HARDCORE PROOF" that this is NOT so! PROOF that you can see with your OWN eyes! Now will it make it work? To some degree, by fooling your transmitter to load into the tuner, which again, you could do with a 48" whip hooked to it. You can post until you are BLUE that this is SO, and again, I will SHOW you PROOF that is is NOT! If it was SO, there would be (1)antenna manufacture that would build 1 antenna the same for everything out there and you then buy your antenna tuner and hook it up to load it. This simply isn't so, and MILLIONS of $$$ are spent every year to improve on antenna design & efficiency. I just don't understand why hams want to continue to live in the dark ages. All of what I have said is also documented and can simply be seen, just looking around. You can load your 80m dipole up on 2meters if you have enough capacitance & inductance to tune out the reactance at the end of the coax, but it doesn't make it resoanant or efficient on 2 meters. If what you and several others have been trying to make other believe, there is one (1) antenna to fit all, just plug in your tuner. NO..it doesn't work that way! And there is NO technical refferance that has ever supported that theory. Broadcaster, cell phone companys and Hams have certainly wasted lots of money going on what you are trying to say. Wake up and smell the coffee man...Stop misleading the hams on here and stop trying to make me look like a fool, neither is correct. You simply CAN NOT TUNE the resonant frequency of the antenna by changing the reactance/impedance or resistance with a tuner in your shack hooked to un-balanced coax. 73 de W4LGH - Alan http://www.w4lgh.com
Reply to a comment by : N4SL on 2007-02-28

I Like Cake.
Reply to a comment by : ONAIR on 2007-02-22

Interesting point. So a resonant vertical dipole would then be a lot more efficient than a vertical that you would need to tune?
W4LGH2007-03-01
RE: Benchmarks
KD2BD wrote.."The tower is resonant at BOTH 660 kHz AND 880 kHz SIMULTANEOUSLY."
======================
You see, you just don't get it. The Antenna (tower) can NOT be RESONANT on either frequency! The Antenna System ,thru the magic of the diplexer, is being matched to both frequencies, and the xmitter, diplexer and any additional matching devices are all together in the "DOG HOUSE" which is right NEXT to the tower. The xmitters thinks(fooled)they are hooked to a resonant load. Again, it is serving a purpose, but NOT the best antenna for the jobs. Two seperate antennas (towers) would be better for both, but NOT cost effective! The diplexer itself has a pretty good loss, but they have power to spare. If we as hams had 50KW worth of antenna current to burn, we too could afford the waste. Running 1500watts helps, but when you are limited to 100watts you can NOT afford this loss much less @ QRP levels.

To have any loading effect on the antenna, the matching device has to be at the antenna, otherwise you are just matching impedance at your radio, and wasting power.

I have installed several diplexed stations, one has 2 AM stations on the HOT tower and 2 FM station on the side mounted FM antenna. Matching for the FM is no problem as the FM antenna is 10mhz broad. The tower was lengthened 25' to throw it out of resonance on both AM frequencies, so both xmitters would have equal loading amd an equal shot at the same antenna.
The tricky part of the FM is the RF choke in the feed line to suck both AM freqs off it, since it is on the HOT tower.

In the case of these 2 stations in NY, you even read that one has a STRONGER signal than the other one, why, because the antenna (tower) is closer to its resonance.

73 de W4LGH - Alan
http://www.w4lgh.com

PS..And I will BET, if you could find any of the original engineers, they would tell you it had a better signal on both stations when the antenna was seperated and loaded for both. It even says it was done away with so that the engineer didn't have to climb the tower for load issues. Read it again!



Reply to a comment by : N4KC on 2007-03-01

John, I wasn't very clear in my statement. I believe what you are actually bringing to resonance with a tuner is the antenna system, not just the antenna. Correct me if I misspoke. After 45 years as a ham, I'm STILL learning about antennas. Also, it is common for not only AM stations but also broadcast FM and TV stations to use the same antenna even though they are on very different frequencies. And the diplexer is typically located at the transmitters, on the ground, not a thousand feet up the tower. Nor do they ever use open wire feedline. Don N4KC www.donkeith.com/n4kc.htm
Reply to a comment by : KD2BD on 2007-03-01

W4LGH wrote: > The antenna matching is done within this diplexer, > and the transmitters are in the DOG HOUSE too! Not > 100' of coax away from the antenna. Exactly. The antenna tuning units and the transmitters share the same building -- something you have repeatedly stated cannot be done unless open wire line is used to feed the antenna. It looks like Heliax was used in this case. The tower is resonant at BOTH 660 kHz AND 880 kHz SIMULTANEOUSLY. And the transmitter's aren't being "fooled". 73, de John, KD2BD
Reply to a comment by : KD2BD on 2007-03-01

N4KC wrote: > I'm not sure anyone here has said that you can "tune > an antenna into resonance" with a "tuner." If they > did, they are incorrect. Don, actually, you CAN. It is well understood that an antenna's natural resonant frequency can easily be modified through an LC network at the feedpoint. It can ALSO be changed in the shack at the other end of the feedline using a similar network, or anywhere else in between, for that matter. Other than the additional loss incurred in the feedline, it does not matter whether the LC network (tuner) is at the feedpoint, or in the shack. The natural resonant frequency of the antenna IS MODIFIED nonetheless through the tuning network. This is what makes it possible to use a 75-meter dipole on 17 through a tuner, or a dipole cut for the phone portion of 75 on the CW portion as well. The tuner allows the antenna system's resonant frequency to be changed to our desired operating frequency without having to change its physical length. It does more than simply match impedances. Realizing a tuning network can modify a single antenna's resonant frequency makes for some VERY interesting possibilities. A pair of tuners properly diplexed into a single antenna can provide perfect resonance on two separate frequencies SIMULTANEOUSLY! That's right! Here's a "real world" example: http://www.fybush.com/site-030424.html This web page describes the operation of two radio stations, WFAN and WCBS, both 50 kW AM stations, 220 kHz apart in frequency, that operate SIMULTANEOUSLY into a single radiating tower. There is a photo toward the bottom of the page that shows a SINGLE length of coaxial transmission line feeding the combined 100 kW carrier (400 kW PEP) from both transmitters into the base of the tower. Originally, the tower included parallel-tuned "traps" toward the top (just like a ham's trap vertical antenna) to establish individual points of resonance at each radio stations' frequency. However, the current arrangement that completely eliminates the traps and instead establishes points of resonance in the antenna tuning network for each transmitter has proven to be a superior approach. 73, de John, KD2BD
Reply to a comment by : KD2BD on 2007-03-01

W4LGH wrote: > Now if you truely believe a tuner in your shack > hooked to coax, will make a 75meter dipole resonant > on 17meters, you have no idea what resonant is or > means, and I can and will gladly show you "HARDCORE > PROOF" that this is NOT so! PROOF that you can see > with your OWN eyes! I don't "believe" a tuner in your shack connected to a coax-fed dipole cut for 75 can be made to resonate on 17. I know it for a fact. A 5/8ths wave vertical isn't a "natural" resonant length for a radiator. Yet, combined with a proper resonating and impedance matching network, it can not only resonate where we want, it also provides some gain (vertical directivity) over a "naturally resonant" quarter wavelength antenna without the additional matching network. So, go ahead. Start off simple. Demonstrate your "hardcore" proof that a 75-meter half-wave dipole fed with RG/8 through a well-designed tuner in the shack cannot become a resonant system on 18 MHz. First, please begin with your definition of "resonant". And please stay away from Wikipedia this time. I want to hear YOUR definition, because as you stated earlier, textbooks are only good as a "starting point". The floor is yours. 73, de John, KD2BD
Reply to a comment by : W4LGH on 2007-02-28

KD2BD wrote..."Standing Wave antennas, on the other hand, are resonant, including operating on 17 meters with a 75 meter coax fed dipole through a tuner. Adjusting the antenna tuner in the shack for a 50 ohm resistive output impedance in this case MAKES THE 75-METER ANTENNA SYSTEM RESONANT ON 17 METERS! And you were proven otherwise. Many times." ======== I fail to see where I have been PROVEN wrong at all. No proof has been offered, other than whats been written in books, and some standard math formulas, that we all know. And I have said, they are great for a starting point. Now if you truely believe a tuner in your shack hooked to coax, will make a 75meter dipole resonant on 17meters, you have no idea what resonant is or means, and I can and will gladly show you "HARDCORE PROOF" that this is NOT so! PROOF that you can see with your OWN eyes! Now will it make it work? To some degree, by fooling your transmitter to load into the tuner, which again, you could do with a 48" whip hooked to it. You can post until you are BLUE that this is SO, and again, I will SHOW you PROOF that is is NOT! If it was SO, there would be (1)antenna manufacture that would build 1 antenna the same for everything out there and you then buy your antenna tuner and hook it up to load it. This simply isn't so, and MILLIONS of $$$ are spent every year to improve on antenna design & efficiency. I just don't understand why hams want to continue to live in the dark ages. All of what I have said is also documented and can simply be seen, just looking around. You can load your 80m dipole up on 2meters if you have enough capacitance & inductance to tune out the reactance at the end of the coax, but it doesn't make it resoanant or efficient on 2 meters. If what you and several others have been trying to make other believe, there is one (1) antenna to fit all, just plug in your tuner. NO..it doesn't work that way! And there is NO technical refferance that has ever supported that theory. Broadcaster, cell phone companys and Hams have certainly wasted lots of money going on what you are trying to say. Wake up and smell the coffee man...Stop misleading the hams on here and stop trying to make me look like a fool, neither is correct. You simply CAN NOT TUNE the resonant frequency of the antenna by changing the reactance/impedance or resistance with a tuner in your shack hooked to un-balanced coax. 73 de W4LGH - Alan http://www.w4lgh.com
Reply to a comment by : N4SL on 2007-02-28

I Like Cake.
Reply to a comment by : ONAIR on 2007-02-22

Interesting point. So a resonant vertical dipole would then be a lot more efficient than a vertical that you would need to tune?
KD2BD2007-03-01
RE: Benchmarks
N4KC wrote:

> John, I wasn't very clear in my statement. I believe
> what you are actually bringing to resonance with a
> tuner is the antenna system, not just the antenna.
> Correct me if I misspoke. After 45 years as a ham,
> I'm STILL learning about antennas.

So's everyone else. :-)

You are correct. The combination of the tuner, the transmission line, and the radiator are brought into resonance, and the resulting impedance matched to the transmitter with proper use of the tuner, regardless of its location in the system.

> Also, it is common for not only AM stations but also
> broadcast FM and TV stations to use the same antenna
> even though they are on very different frequencies.

Correct. The difference between doing this on AM vs. FM or TV is that the FM or TV antennas used in diplexed applications have HUGE bandwidths, and are therefore resonant (and impedance matched, and provide a respectable antenna pattern (gain)) for each station sharing the common antenna.

An AM tower on the other hand, is seldom more than 10 or so kHz wide in bandwidth, so the specific resonant frequencies in a diplexed AM installation must be established through LC networks in the "shack". The height of the tower in this case simply establishes the antenna's radiation pattern, not necessarily the antenna's resonant frequency.

It's done MUCH more often in the FM and television world.

In fact, with the advent of HDTV, many UHF broadcasters have replaced their single channel antennas (Pylons) with broadband panel arrays to be able to diplex both their analog and digital channels through a single antenna and feedline. This saves tower space, and helps to maintain equal coverage between each service.

> And the diplexer is typically located at the
> transmitters, on the ground, not a thousand feet
> up the tower. Nor do they ever use open wire
> feedline.

Imagine that... :-)

Some UHF broadcasters even use waveguide. :-O

> Don N4KC


73, de John, KD2BD
Reply to a comment by : KD2BD on 2007-03-01

K1DA wrote: > The interesting about 660 and 880 am is that if you > live within groundwave range of them, 660 has a better > signal. They both have killer signals into Rhode Island > during the day. WFAN is stronger because the tower is slightly taller than it should be for optimum performance at 880 kHz. The antenna is a compromise in that regard. 73, de John, KD2BD
Reply to a comment by : K1DA on 2007-03-01

The interesting about 660 and 880 am is that if you live within groundwave range of them, 660 has a better signal. They both have killer signals into Rhode Island during the day.
Reply to a comment by : KD2BD on 2007-03-01

N4KC wrote: > I'm not sure anyone here has said that you can "tune > an antenna into resonance" with a "tuner." If they > did, they are incorrect. Don, actually, you CAN. It is well understood that an antenna's natural resonant frequency can easily be modified through an LC network at the feedpoint. It can ALSO be changed in the shack at the other end of the feedline using a similar network, or anywhere else in between, for that matter. Other than the additional loss incurred in the feedline, it does not matter whether the LC network (tuner) is at the feedpoint, or in the shack. The natural resonant frequency of the antenna IS MODIFIED nonetheless through the tuning network. This is what makes it possible to use a 75-meter dipole on 17 through a tuner, or a dipole cut for the phone portion of 75 on the CW portion as well. The tuner allows the antenna system's resonant frequency to be changed to our desired operating frequency without having to change its physical length. It does more than simply match impedances. Realizing a tuning network can modify a single antenna's resonant frequency makes for some VERY interesting possibilities. A pair of tuners properly diplexed into a single antenna can provide perfect resonance on two separate frequencies SIMULTANEOUSLY! That's right! Here's a "real world" example: http://www.fybush.com/site-030424.html This web page describes the operation of two radio stations, WFAN and WCBS, both 50 kW AM stations, 220 kHz apart in frequency, that operate SIMULTANEOUSLY into a single radiating tower. There is a photo toward the bottom of the page that shows a SINGLE length of coaxial transmission line feeding the combined 100 kW carrier (400 kW PEP) from both transmitters into the base of the tower. Originally, the tower included parallel-tuned "traps" toward the top (just like a ham's trap vertical antenna) to establish individual points of resonance at each radio stations' frequency. However, the current arrangement that completely eliminates the traps and instead establishes points of resonance in the antenna tuning network for each transmitter has proven to be a superior approach. 73, de John, KD2BD
Reply to a comment by : KD2BD on 2007-03-01

W4LGH wrote: > Now if you truely believe a tuner in your shack > hooked to coax, will make a 75meter dipole resonant > on 17meters, you have no idea what resonant is or > means, and I can and will gladly show you "HARDCORE > PROOF" that this is NOT so! PROOF that you can see > with your OWN eyes! I don't "believe" a tuner in your shack connected to a coax-fed dipole cut for 75 can be made to resonate on 17. I know it for a fact. A 5/8ths wave vertical isn't a "natural" resonant length for a radiator. Yet, combined with a proper resonating and impedance matching network, it can not only resonate where we want, it also provides some gain (vertical directivity) over a "naturally resonant" quarter wavelength antenna without the additional matching network. So, go ahead. Start off simple. Demonstrate your "hardcore" proof that a 75-meter half-wave dipole fed with RG/8 through a well-designed tuner in the shack cannot become a resonant system on 18 MHz. First, please begin with your definition of "resonant". And please stay away from Wikipedia this time. I want to hear YOUR definition, because as you stated earlier, textbooks are only good as a "starting point". The floor is yours. 73, de John, KD2BD
Reply to a comment by : W4LGH on 2007-02-28

KD2BD wrote..."Standing Wave antennas, on the other hand, are resonant, including operating on 17 meters with a 75 meter coax fed dipole through a tuner. Adjusting the antenna tuner in the shack for a 50 ohm resistive output impedance in this case MAKES THE 75-METER ANTENNA SYSTEM RESONANT ON 17 METERS! And you were proven otherwise. Many times." ======== I fail to see where I have been PROVEN wrong at all. No proof has been offered, other than whats been written in books, and some standard math formulas, that we all know. And I have said, they are great for a starting point. Now if you truely believe a tuner in your shack hooked to coax, will make a 75meter dipole resonant on 17meters, you have no idea what resonant is or means, and I can and will gladly show you "HARDCORE PROOF" that this is NOT so! PROOF that you can see with your OWN eyes! Now will it make it work? To some degree, by fooling your transmitter to load into the tuner, which again, you could do with a 48" whip hooked to it. You can post until you are BLUE that this is SO, and again, I will SHOW you PROOF that is is NOT! If it was SO, there would be (1)antenna manufacture that would build 1 antenna the same for everything out there and you then buy your antenna tuner and hook it up to load it. This simply isn't so, and MILLIONS of $$$ are spent every year to improve on antenna design & efficiency. I just don't understand why hams want to continue to live in the dark ages. All of what I have said is also documented and can simply be seen, just looking around. You can load your 80m dipole up on 2meters if you have enough capacitance & inductance to tune out the reactance at the end of the coax, but it doesn't make it resoanant or efficient on 2 meters. If what you and several others have been trying to make other believe, there is one (1) antenna to fit all, just plug in your tuner. NO..it doesn't work that way! And there is NO technical refferance that has ever supported that theory. Broadcaster, cell phone companys and Hams have certainly wasted lots of money going on what you are trying to say. Wake up and smell the coffee man...Stop misleading the hams on here and stop trying to make me look like a fool, neither is correct. You simply CAN NOT TUNE the resonant frequency of the antenna by changing the reactance/impedance or resistance with a tuner in your shack hooked to un-balanced coax. 73 de W4LGH - Alan http://www.w4lgh.com
Reply to a comment by : N4SL on 2007-02-28

I Like Cake.
Reply to a comment by : ONAIR on 2007-02-22

Interesting point. So a resonant vertical dipole would then be a lot more efficient than a vertical that you would need to tune?
K6IOU2007-03-01
RE: Benchmarks
Hi Al [W4LGH],

I'm going to cut/paste directly from some of your previous posts so I can't be accused of misquoting. Again, all the statements in double quotes are yours:
__________

"The idea of an antenna tuner hooked to an un-balanced line (coax) is absurd."

Al . . . this is exactly what you have in your station when you use some of that beautiful old tube gear of yours.
__________


"The mis-match at the antenna still exsists and is still very REAL!!"

Yes that is correct! And the only result of this is the formation of standing waves and the resultant signal loss because of losses in the feedline. Not a problem with open-wire feedline even with extreme mis-matches. Lots of loss with 'any' type of coax when the SWR rises much above 6:1. No one could expect to radiate much of a signal on 80m with a dipole cut to 66' and with 'any' lengthy piece of coax. No one in this forum has suggested doing this with coax. Again, open feedline . . . no problem.
___________


"I could explain WHY your solid-state rig has a built in antenna tuner, but I am NOT going there, instead.."

They feature a built-in tuner so that they can match 'antenna systems' that are not too far from resonance e.g. the ends of the 80m band when the antenna is cut for mid-band. Probably due to size limitations, however, they can't match as wide a range of impedances as your boat anchor tank circuits.
______________


" I simply said that you can NOT tune your antenna with a tuner in your shack being fed with un-balanced line. (Coax) Now balanced lines are a completely different story, and the feedline becomes part of the antenna."

Sorry Al . . . but currents on a feedline are 'feedline currents' and do not radiate. A balanced feedline never becomes part of the antenna. And this will be repeated more than once . . . YES you can tune your ANTENNA SYSTEM [coax or open wire feedline] with a tuner in the shack.
___________


"You are right that I do enjoy operating vintage Drake equipment, and in one way one could call the tunable tank circuit an antenna tuner, but it really isn't. It is more a matching network for the hi-impedance of the tube outputs to match the low impedance of the antenna, so it is more of an antenna coupler than a tuner."

Whose foolin' who here Al? Call your matching network anything you want but it is no different than a 'transmatch' or 'antenna tuner' or any of a half-dozen names for the same thing.<g>
___________


"We have been talking about transmitting antennas, I would like to know a specific purpose for using a non-resonant antenna on a transmitter."

I can think of several. Probably the most popular is to have one antenna, with balanced feedline, operate on multiple bands with little loss. Another would be for those who don't have the space to put up a full-size antenna.
_____________


"If one truely understands resonance, I don't understand how anything can be as efficient as one that is resonant. And it is proven to you everytime you load up a transmitter."

I believe this is the point! Your ANTENNA SYSTEM is resonant after properly adjusting your antenna tuner. Read Maxwell's treatise on conjugate matching.
_______________


"When I say that an antenna is most efficient at resonance, I am saying the wire is cut to some multiple of the main frequency, 1/4wave, 1/2wave, fullwave etc. being resonate has nothing to do with the feed impedance or an SWR match."

Sure it does. By definition, at resonance the feedpoint impedance is 100% resistive.
____________


"OK, I guess no one is understanding that "The Antenna" is the antenna system, and the entire system HAS to be RESONANT! "

Bingo! That is exactly the purpose of an antenna tuner [external or internal] or your tube gear's tank circuit.
______________


"There is no double standard, it is 2 complely different feed systems. Open or balanced line has comsiderable less loss, its non-shielded so it can and does radiate."

Shielding has nothing to do with it radiating . . . only 'balance' does.
_________________


"Coax is shielded and technically does NOT radiate, you can have common mode currents ride the shield back into the shack, especially if your antenna is not resonant, but this energy is rarely if ever radiated"

Common-mode currents are created by imbalance, resonance has nothing to do with it. And common mode currents certainly do radiate . . . they become part of the antenna.
_______________


"When a tuner is hooked to a coax in your shack, and this coax runs out 100' to your non-resonant antenna, you are NOT tuning your antenna, it is still off resonanace, and it is bouncing currents back into the coax, which can add up to a considerable loss of the actual energy radiated"

It isn't the lack of resonance that is 'bouncing currents' back into the coax. It is the impedance mismatch and ONLY the impedance mismatch between the Zo of the feedline and the input impedance of the antenna that creates SWR. And yes . . . the RF bouncing back and forth between the antenna and tuner loses some energy due to resistive losses in the feedline. That's why balanced line with its insignificant losses gives the best results when trying to operate a dipole far from resonance. And as has been pointed out to you Al, resonance [within a single HF band] only occurs at a single point. When you QSY even a little . . . your precious resonance is gone. I like to keep it 'touched-up' with an antenna tuner.
______________


" Now if you truely believe a tuner in your shack hooked to coax, will make a 75meter dipole resonant on 17meters, you have no idea what resonant is or means,"

Actually it will achieve resonance! Problem is the loss in the coax . . . which will be so extreme that your radiated signal will be zip. Use open-wire feeder and you are back in business! Losses are low and you will actually see some gain in certain directions [offset by the nulls in other directions].
_______________


"You simply CAN NOT TUNE the resonant frequency of the antenna by changing the reactance/impedance or resistance with a tuner in your shack hooked to un-balanced coax."

Once again . . . you CAN tune the reactance out of your ANTENNA SYSTEM so it is, by definition, resonant. You can NOT tune out the SWR between the tuner and antenna with an antenna tuner however. But so what . . . with balanced feedline it really doesn't matter.
_______________


"Now if you have a wire up for , I believe the freq was 3.500mhz and you want to tweak it with an inside antenna tuner for use on 3.850mhz, OK, but you shouldn't have to use a tuner to do this UNLESS you want to see a 1:1 match in your shack, the loss in the tuner could be greater than the loss @ 2:1 ratio"

Problem is Al . . . the SWR would be greater than 2:1 with that frequency deviation. Modern solid-state rigs [most of them anyway] won't deliver full power into that mismatch. Enter the tuner. Of course with your tube gear you can easily QSY and 'match it' with your tank circuit [i.e. antenna tuner].

_______________

Sorry about the long post folks.

DON
K6IOU




Reply to a comment by : W4LGH on 2007-03-01

As I said in an earlier post, I am going to ignor the previous post. I went to the site and read the entire page about 2 transmitters on one tower. This have been done many times, and there are 2 of them right here in the north Florida area. The secret is the diplexer in the "DOG HOUSE" notice that it is sitting AT the antenna? The antenna matching is done within this diplexer, and the transmitters are in the DOG HOUSE too! Not 100' of coax away from the antenna. You can NOT tune the ANTENNA with a tuner hooked to coax from inside your shack. Put the tuner @ the antenna, you can. In the shack, you are only match the impedance on the coax, and a simple SWR meter hooked at the antenna will show this! 73 de W4LGH Alan http://www.w4lgh.com
Reply to a comment by : K9IUQ on 2007-03-01

W4LGH Says :Stanley, simply not understanding, and taking cheap jabs at my knowledge. ...................................................... Stanley taking cheap Jabs?? The Jabs WERE at your knowledge because your knowledge is faulty. These are all YOUR words Cheap Jab AL NO Spin, here are YOUR direct Quotes Al W4LGH Taking Cheap jabs, not at my knowledge but at me Personally: I have some wonderful ocean front property in Arizona that I want to sell you really CHEAP! And I'll even finance it to you! If you call right now, I'll double this offer...2 acres for the price of one! But you have to call in the next 10 minutes, have your CREDIT CARD READY! I guess those infomercials really work! Pay NO attention to the man behind the curtain. I give up here, this guy just isn't with the program... And if N9IUQ wore the covers off the Reflections, it must have been from looking at the pictures and not from reading the text, so the reason they put antenna tuners in radios is so F#$KING IDIOTS like you will BUY THEM!! so the reason they put antenna tuners in radios is so F#$KING IDIOTS like you will BUY THEM!! Well W8JI...I guess the laugh is on you.So I guess you are smarter than all the researchers out there. Thats good, cuz we need more smart people in radio Why is that Stan, did you just learn you are a F#^KING IDIOT? Would you like some cheese to go with that wine? Jesus H Crist Stan...GROW UP! I still say you sir are an IDIOT, and I still think you should buy the ocean front properity in Azronia, while its still a bargin I will send you some cheese to go with your wine, but you can have it all to yourself so go suck an egg!! calling you a F#*KING IDIOT in public So it only took you 45 years to upgrade from General to Extra, ok, thats a little longer than most. ..................................................... Do you even feel a little remorse at how nasty you have been to me? K9IUQ
N4KC2007-03-01
RE: Benchmarks
John, I wasn't very clear in my statement. I believe what you are actually bringing to resonance with a tuner is the antenna system, not just the antenna. Correct me if I misspoke. After 45 years as a ham, I'm STILL learning about antennas.

Also, it is common for not only AM stations but also broadcast FM and TV stations to use the same antenna even though they are on very different frequencies. And the diplexer is typically located at the transmitters, on the ground, not a thousand feet up the tower. Nor do they ever use open wire feedline.

Don N4KC
www.donkeith.com/n4kc.htm
Reply to a comment by : KD2BD on 2007-03-01

W4LGH wrote: > The antenna matching is done within this diplexer, > and the transmitters are in the DOG HOUSE too! Not > 100' of coax away from the antenna. Exactly. The antenna tuning units and the transmitters share the same building -- something you have repeatedly stated cannot be done unless open wire line is used to feed the antenna. It looks like Heliax was used in this case. The tower is resonant at BOTH 660 kHz AND 880 kHz SIMULTANEOUSLY. And the transmitter's aren't being "fooled". 73, de John, KD2BD
Reply to a comment by : KD2BD on 2007-03-01

N4KC wrote: > I'm not sure anyone here has said that you can "tune > an antenna into resonance" with a "tuner." If they > did, they are incorrect. Don, actually, you CAN. It is well understood that an antenna's natural resonant frequency can easily be modified through an LC network at the feedpoint. It can ALSO be changed in the shack at the other end of the feedline using a similar network, or anywhere else in between, for that matter. Other than the additional loss incurred in the feedline, it does not matter whether the LC network (tuner) is at the feedpoint, or in the shack. The natural resonant frequency of the antenna IS MODIFIED nonetheless through the tuning network. This is what makes it possible to use a 75-meter dipole on 17 through a tuner, or a dipole cut for the phone portion of 75 on the CW portion as well. The tuner allows the antenna system's resonant frequency to be changed to our desired operating frequency without having to change its physical length. It does more than simply match impedances. Realizing a tuning network can modify a single antenna's resonant frequency makes for some VERY interesting possibilities. A pair of tuners properly diplexed into a single antenna can provide perfect resonance on two separate frequencies SIMULTANEOUSLY! That's right! Here's a "real world" example: http://www.fybush.com/site-030424.html This web page describes the operation of two radio stations, WFAN and WCBS, both 50 kW AM stations, 220 kHz apart in frequency, that operate SIMULTANEOUSLY into a single radiating tower. There is a photo toward the bottom of the page that shows a SINGLE length of coaxial transmission line feeding the combined 100 kW carrier (400 kW PEP) from both transmitters into the base of the tower. Originally, the tower included parallel-tuned "traps" toward the top (just like a ham's trap vertical antenna) to establish individual points of resonance at each radio stations' frequency. However, the current arrangement that completely eliminates the traps and instead establishes points of resonance in the antenna tuning network for each transmitter has proven to be a superior approach. 73, de John, KD2BD
Reply to a comment by : KD2BD on 2007-03-01

W4LGH wrote: > Now if you truely believe a tuner in your shack > hooked to coax, will make a 75meter dipole resonant > on 17meters, you have no idea what resonant is or > means, and I can and will gladly show you "HARDCORE > PROOF" that this is NOT so! PROOF that you can see > with your OWN eyes! I don't "believe" a tuner in your shack connected to a coax-fed dipole cut for 75 can be made to resonate on 17. I know it for a fact. A 5/8ths wave vertical isn't a "natural" resonant length for a radiator. Yet, combined with a proper resonating and impedance matching network, it can not only resonate where we want, it also provides some gain (vertical directivity) over a "naturally resonant" quarter wavelength antenna without the additional matching network. So, go ahead. Start off simple. Demonstrate your "hardcore" proof that a 75-meter half-wave dipole fed with RG/8 through a well-designed tuner in the shack cannot become a resonant system on 18 MHz. First, please begin with your definition of "resonant". And please stay away from Wikipedia this time. I want to hear YOUR definition, because as you stated earlier, textbooks are only good as a "starting point". The floor is yours. 73, de John, KD2BD
Reply to a comment by : W4LGH on 2007-02-28

KD2BD wrote..."Standing Wave antennas, on the other hand, are resonant, including operating on 17 meters with a 75 meter coax fed dipole through a tuner. Adjusting the antenna tuner in the shack for a 50 ohm resistive output impedance in this case MAKES THE 75-METER ANTENNA SYSTEM RESONANT ON 17 METERS! And you were proven otherwise. Many times." ======== I fail to see where I have been PROVEN wrong at all. No proof has been offered, other than whats been written in books, and some standard math formulas, that we all know. And I have said, they are great for a starting point. Now if you truely believe a tuner in your shack hooked to coax, will make a 75meter dipole resonant on 17meters, you have no idea what resonant is or means, and I can and will gladly show you "HARDCORE PROOF" that this is NOT so! PROOF that you can see with your OWN eyes! Now will it make it work? To some degree, by fooling your transmitter to load into the tuner, which again, you could do with a 48" whip hooked to it. You can post until you are BLUE that this is SO, and again, I will SHOW you PROOF that is is NOT! If it was SO, there would be (1)antenna manufacture that would build 1 antenna the same for everything out there and you then buy your antenna tuner and hook it up to load it. This simply isn't so, and MILLIONS of $$$ are spent every year to improve on antenna design & efficiency. I just don't understand why hams want to continue to live in the dark ages. All of what I have said is also documented and can simply be seen, just looking around. You can load your 80m dipole up on 2meters if you have enough capacitance & inductance to tune out the reactance at the end of the coax, but it doesn't make it resoanant or efficient on 2 meters. If what you and several others have been trying to make other believe, there is one (1) antenna to fit all, just plug in your tuner. NO..it doesn't work that way! And there is NO technical refferance that has ever supported that theory. Broadcaster, cell phone companys and Hams have certainly wasted lots of money going on what you are trying to say. Wake up and smell the coffee man...Stop misleading the hams on here and stop trying to make me look like a fool, neither is correct. You simply CAN NOT TUNE the resonant frequency of the antenna by changing the reactance/impedance or resistance with a tuner in your shack hooked to un-balanced coax. 73 de W4LGH - Alan http://www.w4lgh.com
Reply to a comment by : N4SL on 2007-02-28

I Like Cake.
Reply to a comment by : ONAIR on 2007-02-22

Interesting point. So a resonant vertical dipole would then be a lot more efficient than a vertical that you would need to tune?
KD2BD2007-03-01
RE: Benchmarks
K1DA wrote:

> The interesting about 660 and 880 am is that if you
> live within groundwave range of them, 660 has a better
> signal. They both have killer signals into Rhode Island
> during the day.

WFAN is stronger because the tower is slightly taller than it should be for optimum performance at 880 kHz. The antenna is a compromise in that regard.


73, de John, KD2BD
Reply to a comment by : K1DA on 2007-03-01

The interesting about 660 and 880 am is that if you live within groundwave range of them, 660 has a better signal. They both have killer signals into Rhode Island during the day.
Reply to a comment by : KD2BD on 2007-03-01

N4KC wrote: > I'm not sure anyone here has said that you can "tune > an antenna into resonance" with a "tuner." If they > did, they are incorrect. Don, actually, you CAN. It is well understood that an antenna's natural resonant frequency can easily be modified through an LC network at the feedpoint. It can ALSO be changed in the shack at the other end of the feedline using a similar network, or anywhere else in between, for that matter. Other than the additional loss incurred in the feedline, it does not matter whether the LC network (tuner) is at the feedpoint, or in the shack. The natural resonant frequency of the antenna IS MODIFIED nonetheless through the tuning network. This is what makes it possible to use a 75-meter dipole on 17 through a tuner, or a dipole cut for the phone portion of 75 on the CW portion as well. The tuner allows the antenna system's resonant frequency to be changed to our desired operating frequency without having to change its physical length. It does more than simply match impedances. Realizing a tuning network can modify a single antenna's resonant frequency makes for some VERY interesting possibilities. A pair of tuners properly diplexed into a single antenna can provide perfect resonance on two separate frequencies SIMULTANEOUSLY! That's right! Here's a "real world" example: http://www.fybush.com/site-030424.html This web page describes the operation of two radio stations, WFAN and WCBS, both 50 kW AM stations, 220 kHz apart in frequency, that operate SIMULTANEOUSLY into a single radiating tower. There is a photo toward the bottom of the page that shows a SINGLE length of coaxial transmission line feeding the combined 100 kW carrier (400 kW PEP) from both transmitters into the base of the tower. Originally, the tower included parallel-tuned "traps" toward the top (just like a ham's trap vertical antenna) to establish individual points of resonance at each radio stations' frequency. However, the current arrangement that completely eliminates the traps and instead establishes points of resonance in the antenna tuning network for each transmitter has proven to be a superior approach. 73, de John, KD2BD
Reply to a comment by : KD2BD on 2007-03-01

W4LGH wrote: > Now if you truely believe a tuner in your shack > hooked to coax, will make a 75meter dipole resonant > on 17meters, you have no idea what resonant is or > means, and I can and will gladly show you "HARDCORE > PROOF" that this is NOT so! PROOF that you can see > with your OWN eyes! I don't "believe" a tuner in your shack connected to a coax-fed dipole cut for 75 can be made to resonate on 17. I know it for a fact. A 5/8ths wave vertical isn't a "natural" resonant length for a radiator. Yet, combined with a proper resonating and impedance matching network, it can not only resonate where we want, it also provides some gain (vertical directivity) over a "naturally resonant" quarter wavelength antenna without the additional matching network. So, go ahead. Start off simple. Demonstrate your "hardcore" proof that a 75-meter half-wave dipole fed with RG/8 through a well-designed tuner in the shack cannot become a resonant system on 18 MHz. First, please begin with your definition of "resonant". And please stay away from Wikipedia this time. I want to hear YOUR definition, because as you stated earlier, textbooks are only good as a "starting point". The floor is yours. 73, de John, KD2BD
Reply to a comment by : W4LGH on 2007-02-28

KD2BD wrote..."Standing Wave antennas, on the other hand, are resonant, including operating on 17 meters with a 75 meter coax fed dipole through a tuner. Adjusting the antenna tuner in the shack for a 50 ohm resistive output impedance in this case MAKES THE 75-METER ANTENNA SYSTEM RESONANT ON 17 METERS! And you were proven otherwise. Many times." ======== I fail to see where I have been PROVEN wrong at all. No proof has been offered, other than whats been written in books, and some standard math formulas, that we all know. And I have said, they are great for a starting point. Now if you truely believe a tuner in your shack hooked to coax, will make a 75meter dipole resonant on 17meters, you have no idea what resonant is or means, and I can and will gladly show you "HARDCORE PROOF" that this is NOT so! PROOF that you can see with your OWN eyes! Now will it make it work? To some degree, by fooling your transmitter to load into the tuner, which again, you could do with a 48" whip hooked to it. You can post until you are BLUE that this is SO, and again, I will SHOW you PROOF that is is NOT! If it was SO, there would be (1)antenna manufacture that would build 1 antenna the same for everything out there and you then buy your antenna tuner and hook it up to load it. This simply isn't so, and MILLIONS of $$$ are spent every year to improve on antenna design & efficiency. I just don't understand why hams want to continue to live in the dark ages. All of what I have said is also documented and can simply be seen, just looking around. You can load your 80m dipole up on 2meters if you have enough capacitance & inductance to tune out the reactance at the end of the coax, but it doesn't make it resoanant or efficient on 2 meters. If what you and several others have been trying to make other believe, there is one (1) antenna to fit all, just plug in your tuner. NO..it doesn't work that way! And there is NO technical refferance that has ever supported that theory. Broadcaster, cell phone companys and Hams have certainly wasted lots of money going on what you are trying to say. Wake up and smell the coffee man...Stop misleading the hams on here and stop trying to make me look like a fool, neither is correct. You simply CAN NOT TUNE the resonant frequency of the antenna by changing the reactance/impedance or resistance with a tuner in your shack hooked to un-balanced coax. 73 de W4LGH - Alan http://www.w4lgh.com
Reply to a comment by : N4SL on 2007-02-28

I Like Cake.
Reply to a comment by : ONAIR on 2007-02-22

Interesting point. So a resonant vertical dipole would then be a lot more efficient than a vertical that you would need to tune?
KD2BD2007-03-01
RE: Benchmarks
W4LGH wrote:

> The antenna matching is done within this diplexer,
> and the transmitters are in the DOG HOUSE too! Not
> 100' of coax away from the antenna.

Exactly. The antenna tuning units and the transmitters share the same building -- something you have repeatedly stated cannot be done unless open wire line is used to feed the antenna.

It looks like Heliax was used in this case.

The tower is resonant at BOTH 660 kHz AND 880 kHz SIMULTANEOUSLY.

And the transmitter's aren't being "fooled".


73, de John, KD2BD
Reply to a comment by : KD2BD on 2007-03-01

N4KC wrote: > I'm not sure anyone here has said that you can "tune > an antenna into resonance" with a "tuner." If they > did, they are incorrect. Don, actually, you CAN. It is well understood that an antenna's natural resonant frequency can easily be modified through an LC network at the feedpoint. It can ALSO be changed in the shack at the other end of the feedline using a similar network, or anywhere else in between, for that matter. Other than the additional loss incurred in the feedline, it does not matter whether the LC network (tuner) is at the feedpoint, or in the shack. The natural resonant frequency of the antenna IS MODIFIED nonetheless through the tuning network. This is what makes it possible to use a 75-meter dipole on 17 through a tuner, or a dipole cut for the phone portion of 75 on the CW portion as well. The tuner allows the antenna system's resonant frequency to be changed to our desired operating frequency without having to change its physical length. It does more than simply match impedances. Realizing a tuning network can modify a single antenna's resonant frequency makes for some VERY interesting possibilities. A pair of tuners properly diplexed into a single antenna can provide perfect resonance on two separate frequencies SIMULTANEOUSLY! That's right! Here's a "real world" example: http://www.fybush.com/site-030424.html This web page describes the operation of two radio stations, WFAN and WCBS, both 50 kW AM stations, 220 kHz apart in frequency, that operate SIMULTANEOUSLY into a single radiating tower. There is a photo toward the bottom of the page that shows a SINGLE length of coaxial transmission line feeding the combined 100 kW carrier (400 kW PEP) from both transmitters into the base of the tower. Originally, the tower included parallel-tuned "traps" toward the top (just like a ham's trap vertical antenna) to establish individual points of resonance at each radio stations' frequency. However, the current arrangement that completely eliminates the traps and instead establishes points of resonance in the antenna tuning network for each transmitter has proven to be a superior approach. 73, de John, KD2BD
Reply to a comment by : KD2BD on 2007-03-01

W4LGH wrote: > Now if you truely believe a tuner in your shack > hooked to coax, will make a 75meter dipole resonant > on 17meters, you have no idea what resonant is or > means, and I can and will gladly show you "HARDCORE > PROOF" that this is NOT so! PROOF that you can see > with your OWN eyes! I don't "believe" a tuner in your shack connected to a coax-fed dipole cut for 75 can be made to resonate on 17. I know it for a fact. A 5/8ths wave vertical isn't a "natural" resonant length for a radiator. Yet, combined with a proper resonating and impedance matching network, it can not only resonate where we want, it also provides some gain (vertical directivity) over a "naturally resonant" quarter wavelength antenna without the additional matching network. So, go ahead. Start off simple. Demonstrate your "hardcore" proof that a 75-meter half-wave dipole fed with RG/8 through a well-designed tuner in the shack cannot become a resonant system on 18 MHz. First, please begin with your definition of "resonant". And please stay away from Wikipedia this time. I want to hear YOUR definition, because as you stated earlier, textbooks are only good as a "starting point". The floor is yours. 73, de John, KD2BD
Reply to a comment by : W4LGH on 2007-02-28

KD2BD wrote..."Standing Wave antennas, on the other hand, are resonant, including operating on 17 meters with a 75 meter coax fed dipole through a tuner. Adjusting the antenna tuner in the shack for a 50 ohm resistive output impedance in this case MAKES THE 75-METER ANTENNA SYSTEM RESONANT ON 17 METERS! And you were proven otherwise. Many times." ======== I fail to see where I have been PROVEN wrong at all. No proof has been offered, other than whats been written in books, and some standard math formulas, that we all know. And I have said, they are great for a starting point. Now if you truely believe a tuner in your shack hooked to coax, will make a 75meter dipole resonant on 17meters, you have no idea what resonant is or means, and I can and will gladly show you "HARDCORE PROOF" that this is NOT so! PROOF that you can see with your OWN eyes! Now will it make it work? To some degree, by fooling your transmitter to load into the tuner, which again, you could do with a 48" whip hooked to it. You can post until you are BLUE that this is SO, and again, I will SHOW you PROOF that is is NOT! If it was SO, there would be (1)antenna manufacture that would build 1 antenna the same for everything out there and you then buy your antenna tuner and hook it up to load it. This simply isn't so, and MILLIONS of $$$ are spent every year to improve on antenna design & efficiency. I just don't understand why hams want to continue to live in the dark ages. All of what I have said is also documented and can simply be seen, just looking around. You can load your 80m dipole up on 2meters if you have enough capacitance & inductance to tune out the reactance at the end of the coax, but it doesn't make it resoanant or efficient on 2 meters. If what you and several others have been trying to make other believe, there is one (1) antenna to fit all, just plug in your tuner. NO..it doesn't work that way! And there is NO technical refferance that has ever supported that theory. Broadcaster, cell phone companys and Hams have certainly wasted lots of money going on what you are trying to say. Wake up and smell the coffee man...Stop misleading the hams on here and stop trying to make me look like a fool, neither is correct. You simply CAN NOT TUNE the resonant frequency of the antenna by changing the reactance/impedance or resistance with a tuner in your shack hooked to un-balanced coax. 73 de W4LGH - Alan http://www.w4lgh.com
Reply to a comment by : N4SL on 2007-02-28

I Like Cake.
Reply to a comment by : ONAIR on 2007-02-22

Interesting point. So a resonant vertical dipole would then be a lot more efficient than a vertical that you would need to tune?
K1DA2007-03-01
RE: Benchmarks
The interesting about 660 and 880 am is that if you live within groundwave range of them, 660 has a better signal. They both have killer signals into Rhode Island during the day.
Reply to a comment by : KD2BD on 2007-03-01

N4KC wrote: > I'm not sure anyone here has said that you can "tune > an antenna into resonance" with a "tuner." If they > did, they are incorrect. Don, actually, you CAN. It is well understood that an antenna's natural resonant frequency can easily be modified through an LC network at the feedpoint. It can ALSO be changed in the shack at the other end of the feedline using a similar network, or anywhere else in between, for that matter. Other than the additional loss incurred in the feedline, it does not matter whether the LC network (tuner) is at the feedpoint, or in the shack. The natural resonant frequency of the antenna IS MODIFIED nonetheless through the tuning network. This is what makes it possible to use a 75-meter dipole on 17 through a tuner, or a dipole cut for the phone portion of 75 on the CW portion as well. The tuner allows the antenna system's resonant frequency to be changed to our desired operating frequency without having to change its physical length. It does more than simply match impedances. Realizing a tuning network can modify a single antenna's resonant frequency makes for some VERY interesting possibilities. A pair of tuners properly diplexed into a single antenna can provide perfect resonance on two separate frequencies SIMULTANEOUSLY! That's right! Here's a "real world" example: http://www.fybush.com/site-030424.html This web page describes the operation of two radio stations, WFAN and WCBS, both 50 kW AM stations, 220 kHz apart in frequency, that operate SIMULTANEOUSLY into a single radiating tower. There is a photo toward the bottom of the page that shows a SINGLE length of coaxial transmission line feeding the combined 100 kW carrier (400 kW PEP) from both transmitters into the base of the tower. Originally, the tower included parallel-tuned "traps" toward the top (just like a ham's trap vertical antenna) to establish individual points of resonance at each radio stations' frequency. However, the current arrangement that completely eliminates the traps and instead establishes points of resonance in the antenna tuning network for each transmitter has proven to be a superior approach. 73, de John, KD2BD
Reply to a comment by : KD2BD on 2007-03-01

W4LGH wrote: > Now if you truely believe a tuner in your shack > hooked to coax, will make a 75meter dipole resonant > on 17meters, you have no idea what resonant is or > means, and I can and will gladly show you "HARDCORE > PROOF" that this is NOT so! PROOF that you can see > with your OWN eyes! I don't "believe" a tuner in your shack connected to a coax-fed dipole cut for 75 can be made to resonate on 17. I know it for a fact. A 5/8ths wave vertical isn't a "natural" resonant length for a radiator. Yet, combined with a proper resonating and impedance matching network, it can not only resonate where we want, it also provides some gain (vertical directivity) over a "naturally resonant" quarter wavelength antenna without the additional matching network. So, go ahead. Start off simple. Demonstrate your "hardcore" proof that a 75-meter half-wave dipole fed with RG/8 through a well-designed tuner in the shack cannot become a resonant system on 18 MHz. First, please begin with your definition of "resonant". And please stay away from Wikipedia this time. I want to hear YOUR definition, because as you stated earlier, textbooks are only good as a "starting point". The floor is yours. 73, de John, KD2BD
Reply to a comment by : W4LGH on 2007-02-28

KD2BD wrote..."Standing Wave antennas, on the other hand, are resonant, including operating on 17 meters with a 75 meter coax fed dipole through a tuner. Adjusting the antenna tuner in the shack for a 50 ohm resistive output impedance in this case MAKES THE 75-METER ANTENNA SYSTEM RESONANT ON 17 METERS! And you were proven otherwise. Many times." ======== I fail to see where I have been PROVEN wrong at all. No proof has been offered, other than whats been written in books, and some standard math formulas, that we all know. And I have said, they are great for a starting point. Now if you truely believe a tuner in your shack hooked to coax, will make a 75meter dipole resonant on 17meters, you have no idea what resonant is or means, and I can and will gladly show you "HARDCORE PROOF" that this is NOT so! PROOF that you can see with your OWN eyes! Now will it make it work? To some degree, by fooling your transmitter to load into the tuner, which again, you could do with a 48" whip hooked to it. You can post until you are BLUE that this is SO, and again, I will SHOW you PROOF that is is NOT! If it was SO, there would be (1)antenna manufacture that would build 1 antenna the same for everything out there and you then buy your antenna tuner and hook it up to load it. This simply isn't so, and MILLIONS of $$$ are spent every year to improve on antenna design & efficiency. I just don't understand why hams want to continue to live in the dark ages. All of what I have said is also documented and can simply be seen, just looking around. You can load your 80m dipole up on 2meters if you have enough capacitance & inductance to tune out the reactance at the end of the coax, but it doesn't make it resoanant or efficient on 2 meters. If what you and several others have been trying to make other believe, there is one (1) antenna to fit all, just plug in your tuner. NO..it doesn't work that way! And there is NO technical refferance that has ever supported that theory. Broadcaster, cell phone companys and Hams have certainly wasted lots of money going on what you are trying to say. Wake up and smell the coffee man...Stop misleading the hams on here and stop trying to make me look like a fool, neither is correct. You simply CAN NOT TUNE the resonant frequency of the antenna by changing the reactance/impedance or resistance with a tuner in your shack hooked to un-balanced coax. 73 de W4LGH - Alan http://www.w4lgh.com
Reply to a comment by : N4SL on 2007-02-28

I Like Cake.
Reply to a comment by : ONAIR on 2007-02-22

Interesting point. So a resonant vertical dipole would then be a lot more efficient than a vertical that you would need to tune?
K9IUQ2007-03-01
Benchmarks
W4LGH says: As I said in an earlier post, I am going to ignor the previous post.
...........................................

I dont blame you, if I said all that stupid nasty stuff I would want to ignore it too.

K9IUQ
W4LGH2007-03-01
RE: Benchmarks
As I said in an earlier post, I am going to ignor the previous post. I went to the site and read the entire page about 2 transmitters on one tower. This have been done many times, and there are 2 of them right here in the north Florida area. The secret is the diplexer in the "DOG HOUSE" notice that it is sitting AT the antenna? The antenna matching is done within this diplexer, and the transmitters are in the DOG HOUSE too! Not 100' of coax away from the antenna.

You can NOT tune the ANTENNA with a tuner hooked to coax from inside your shack. Put the tuner @ the antenna, you can. In the shack, you are only match the impedance on the coax, and a simple SWR meter hooked at the antenna will show this!

73 de W4LGH Alan
http://www.w4lgh.com

Reply to a comment by : K9IUQ on 2007-03-01

W4LGH Says :Stanley, simply not understanding, and taking cheap jabs at my knowledge. ...................................................... Stanley taking cheap Jabs?? The Jabs WERE at your knowledge because your knowledge is faulty. These are all YOUR words Cheap Jab AL NO Spin, here are YOUR direct Quotes Al W4LGH Taking Cheap jabs, not at my knowledge but at me Personally: I have some wonderful ocean front property in Arizona that I want to sell you really CHEAP! And I'll even finance it to you! If you call right now, I'll double this offer...2 acres for the price of one! But you have to call in the next 10 minutes, have your CREDIT CARD READY! I guess those infomercials really work! Pay NO attention to the man behind the curtain. I give up here, this guy just isn't with the program... And if N9IUQ wore the covers off the Reflections, it must have been from looking at the pictures and not from reading the text, so the reason they put antenna tuners in radios is so F#$KING IDIOTS like you will BUY THEM!! so the reason they put antenna tuners in radios is so F#$KING IDIOTS like you will BUY THEM!! Well W8JI...I guess the laugh is on you.So I guess you are smarter than all the researchers out there. Thats good, cuz we need more smart people in radio Why is that Stan, did you just learn you are a F#^KING IDIOT? Would you like some cheese to go with that wine? Jesus H Crist Stan...GROW UP! I still say you sir are an IDIOT, and I still think you should buy the ocean front properity in Azronia, while its still a bargin I will send you some cheese to go with your wine, but you can have it all to yourself so go suck an egg!! calling you a F#*KING IDIOT in public So it only took you 45 years to upgrade from General to Extra, ok, thats a little longer than most. ..................................................... Do you even feel a little remorse at how nasty you have been to me? K9IUQ
K9IUQ2007-03-01
Benchmarks
W4LGH Says :Stanley, simply not understanding, and taking cheap jabs at my knowledge.

......................................................
Stanley taking cheap Jabs?? The Jabs WERE at your knowledge because your knowledge is faulty.

These are all YOUR words Cheap Jab AL


NO Spin, here are YOUR direct Quotes Al
W4LGH Taking Cheap jabs, not at my knowledge but at me Personally:

I have some wonderful ocean front property in Arizona that I want to sell you really CHEAP! And I'll even finance it to you! If you call right now, I'll double this offer...2 acres for the price of one! But you have to call in the next 10 minutes, have your CREDIT CARD READY!

I guess those infomercials really work!
Pay NO attention to the man behind the curtain.

I give up here, this guy just isn't with the program...

And if N9IUQ wore the covers off the Reflections, it must have been from looking at the pictures and not from reading the text,

so the reason they put antenna tuners in radios is so F#$KING IDIOTS like you will BUY THEM!!
so the reason they put antenna tuners in radios is so F#$KING IDIOTS like you will BUY THEM!!

Well W8JI...I guess the laugh is on you.So I guess you are smarter than all the researchers out there. Thats good, cuz we need more smart people in radio

Why is that Stan, did you just learn you are a F#^KING IDIOT? Would you like some cheese to go with that wine?

Jesus H Crist Stan...GROW UP!

I still
say you sir are an IDIOT, and I still think you should buy the ocean front properity in Azronia, while its still a bargin

I will send you some cheese to go with your wine, but you can have it all to yourself

so go suck an egg!!

calling you a F#*KING IDIOT in public

So it only took you 45 years to upgrade from General to Extra, ok, thats a little longer than most.

.....................................................
Do you even feel a little remorse at how nasty you have been to me?

K9IUQ











KD2BD2007-03-01
RE: Benchmarks
N4KC wrote:

> I'm not sure anyone here has said that you can "tune
> an antenna into resonance" with a "tuner." If they
> did, they are incorrect.

Don, actually, you CAN. It is well understood that an antenna's natural resonant frequency can easily be modified through an LC network at the feedpoint. It can ALSO be changed in the shack at the other end of the feedline using a similar network, or anywhere else in between, for that matter.

Other than the additional loss incurred in the feedline, it does not matter whether the LC network (tuner) is at the feedpoint, or in the shack. The natural resonant frequency of the antenna IS MODIFIED nonetheless through the tuning network.

This is what makes it possible to use a 75-meter dipole on 17 through a tuner, or a dipole cut for the phone portion of 75 on the CW portion as well. The tuner allows the antenna system's resonant frequency to be changed to our desired operating frequency without having to change its physical length. It does more than simply match impedances.

Realizing a tuning network can modify a single antenna's resonant frequency makes for some VERY interesting possibilities. A pair of tuners properly diplexed into a single antenna can provide perfect resonance on two separate frequencies SIMULTANEOUSLY!

That's right!

Here's a "real world" example:

http://www.fybush.com/site-030424.html

This web page describes the operation of two radio stations, WFAN and WCBS, both 50 kW AM stations, 220 kHz apart in frequency, that operate SIMULTANEOUSLY into a single radiating tower.

There is a photo toward the bottom of the page that shows a SINGLE length of coaxial transmission line feeding the combined 100 kW carrier (400 kW PEP) from both transmitters into the base of the tower.

Originally, the tower included parallel-tuned "traps" toward the top (just like a ham's trap vertical antenna) to establish individual points of resonance at each radio stations' frequency. However, the current arrangement that completely eliminates the traps and instead establishes points of resonance in the antenna tuning network for each transmitter has proven to be a superior approach.


73, de John, KD2BD
Reply to a comment by : KD2BD on 2007-03-01

W4LGH wrote: > Now if you truely believe a tuner in your shack > hooked to coax, will make a 75meter dipole resonant > on 17meters, you have no idea what resonant is or > means, and I can and will gladly show you "HARDCORE > PROOF" that this is NOT so! PROOF that you can see > with your OWN eyes! I don't "believe" a tuner in your shack connected to a coax-fed dipole cut for 75 can be made to resonate on 17. I know it for a fact. A 5/8ths wave vertical isn't a "natural" resonant length for a radiator. Yet, combined with a proper resonating and impedance matching network, it can not only resonate where we want, it also provides some gain (vertical directivity) over a "naturally resonant" quarter wavelength antenna without the additional matching network. So, go ahead. Start off simple. Demonstrate your "hardcore" proof that a 75-meter half-wave dipole fed with RG/8 through a well-designed tuner in the shack cannot become a resonant system on 18 MHz. First, please begin with your definition of "resonant". And please stay away from Wikipedia this time. I want to hear YOUR definition, because as you stated earlier, textbooks are only good as a "starting point". The floor is yours. 73, de John, KD2BD
Reply to a comment by : W4LGH on 2007-02-28

KD2BD wrote..."Standing Wave antennas, on the other hand, are resonant, including operating on 17 meters with a 75 meter coax fed dipole through a tuner. Adjusting the antenna tuner in the shack for a 50 ohm resistive output impedance in this case MAKES THE 75-METER ANTENNA SYSTEM RESONANT ON 17 METERS! And you were proven otherwise. Many times." ======== I fail to see where I have been PROVEN wrong at all. No proof has been offered, other than whats been written in books, and some standard math formulas, that we all know. And I have said, they are great for a starting point. Now if you truely believe a tuner in your shack hooked to coax, will make a 75meter dipole resonant on 17meters, you have no idea what resonant is or means, and I can and will gladly show you "HARDCORE PROOF" that this is NOT so! PROOF that you can see with your OWN eyes! Now will it make it work? To some degree, by fooling your transmitter to load into the tuner, which again, you could do with a 48" whip hooked to it. You can post until you are BLUE that this is SO, and again, I will SHOW you PROOF that is is NOT! If it was SO, there would be (1)antenna manufacture that would build 1 antenna the same for everything out there and you then buy your antenna tuner and hook it up to load it. This simply isn't so, and MILLIONS of $$$ are spent every year to improve on antenna design & efficiency. I just don't understand why hams want to continue to live in the dark ages. All of what I have said is also documented and can simply be seen, just looking around. You can load your 80m dipole up on 2meters if you have enough capacitance & inductance to tune out the reactance at the end of the coax, but it doesn't make it resoanant or efficient on 2 meters. If what you and several others have been trying to make other believe, there is one (1) antenna to fit all, just plug in your tuner. NO..it doesn't work that way! And there is NO technical refferance that has ever supported that theory. Broadcaster, cell phone companys and Hams have certainly wasted lots of money going on what you are trying to say. Wake up and smell the coffee man...Stop misleading the hams on here and stop trying to make me look like a fool, neither is correct. You simply CAN NOT TUNE the resonant frequency of the antenna by changing the reactance/impedance or resistance with a tuner in your shack hooked to un-balanced coax. 73 de W4LGH - Alan http://www.w4lgh.com
Reply to a comment by : N4SL on 2007-02-28

I Like Cake.
Reply to a comment by : ONAIR on 2007-02-22

Interesting point. So a resonant vertical dipole would then be a lot more efficient than a vertical that you would need to tune?
N4KC2007-03-01
RE: Benchmarks
Alan, "discourse" means "communicating on a subject by words," and is not a negative thing! In fact, it beats communicating with bullets and butcher knives!

I still don't agree with your original statement as you quoted it: "The idea of an antenna tuner hooked to an un-balanced line (coax) is absurd." I think we have seen many instances where it is a smart and effective thing to do. And though I'm sure some hams think things are hunky-dory, regardless of what is on the other end of the coax so long as the cross-needle meter shows low SWR, most of us are aware that using a matching device to overcome a big mismatch and high SWR...with COAX feedlines...is a compromise, the magnitude of which depends on many factors. We are not fooled at all. We merely do what we must.

My point is, you don't have to "change the antenna." Use transmission line that is low loss enough that standing waves are virtually no factor and a good enough matching device...wherever it is located...to allow your transmitter to emit full power without spittin' and sparkin'.

I don't recall your offering the qualification you gave us in this latest post: "I am spreaking of 1 frequency, lets say 3850khz on a wire that is cut to that freq. This will work better than a 66' wire fed with 100' of rg8x coax into an antenna tuner, tuned so that the radio is putting out full power." Can't say I'd argue with that statement at all, and that's NOT what all these guys have been saying either.

Again:
-- There are times and setups where using a "tuner" with coax is not only NOT "absurd" but downright useful.

-- A non-resonant antenna, in a whole bunch of ways, can be more effective than a resonant one.

-- Within reason and with the proper setup (feedline, matching device), the relative resonance of a radiator or the standing waves generated on an antenna system are virtually immaterial in its use or efficiency.

Agreed?

Don N4KC
www.donkeith.com/n4kc.htm

Reply to a comment by : W4LGH on 2007-03-01

Don...here is a clip of what my first post stated.... "The idea of an antenna tuner hooked to an un-balanced line (coax) is absurd. The only thing you are tuning is the impedance at the shack end of the coax. The mis-match at the antenna still exsists and is still very REAL!! It may allow you to do something you couldn't without it, but you are only fooling yourself!" Now after some 100+ post of everyone saying something else, its starting to turn around. Just like I said with mobile antennas, the matching device has to be at the antenna end to change the antenna. With the use of varible inductance at the antenna, you can change its resonant freq. I guess where I screwed up in the first post, as I assumed everyone would follow, but guess not, would have been to finsh the line "but you are only fooling yourself, if you think you are tuning the antenna!" I have never said what was being done didn't work, I said there were induced losses. Yes when I say RESONANT is better, I am spreaking of 1 frequency, lets say 3850khz on a wire that is cut to that freq. This will work better than a 66' wire fed with 100' of rg8x coax into an antenna tuner, tuned so that the radio is putting out full power. This is where the better comes from. And I have seen this over and over, and these guys actually believe they are yuning their antenna. This simply is NOT true. So I thank you Don, as so far you are starting to understand where I have been coming from from the begining. No, My intent was NOT to cause discontent in this thread. Most of that was due to Stanley, simply not understanding, and taking cheap jabs at my knowledge. Over and over he has had some stupid comment to make about what I said, when he himself did not understand what I was saying. So I am big enough to applogize for causing this discontent, but one can only take so many stupid jabs. 73 de W4LGH Alan http://www.w4lgh.com
Reply to a comment by : N4KC on 2007-03-01

Alan, funny thing is, we all probably agree on more than we realize. I think it is just the degree to which you take a few of your ideas that are offputting to some. W4EF pointed out a perfect example. Using a tuner to try to match a long run of coax to a dipole that is way, way out of resonance will not give sterling performance. We agree on that. Using a tuner to get a match to a reasonable run of coax to stretch the usefulness of an antenna system that is not so far out of resonance is not "stupid" or "absurd." In the latter case, the loss of the standing waves in the coaxial feedline can range from negligible to tolerable, and it is an easy compromise for most of us to make if we are unable to erect an antenna that is resonant everywhere we desire to operate. I think you are admitting in your last post that you acknowledge that the formulae and theories we've been arguing about for the last week are actually valid and useful. Yes, results may vary, depending on many, many factors. And ultimately, the proof is in the pudding. That's why we put up antennas based on tried and true formulae, but then we test and measure and tweak. I'm not sure anyone here has said that you can "tune an antenna into resonance" with a "tuner." If they did, they are incorrect. An antenna system is resonant at a given frequency or it is not. You can change that point of resonance in some ways, such as by trimming or adding some wire, for example. A matching device, which can be what we typically call a "tuner," can be employed to allow the operator to match the output impedance of his rig to whatever the impedance of the antenna system is...on the desk, along the transmission line, or at the feedpoint of the antenna itself, all in an effort to use the antenna system on more than just the resonant frequency. Results can be good or they can be horrible, depending on several factors. I think we're mostly all still in agreement, right? Here's the biggie, though. You still maintain that a resonant antenna is "better" than a non-resonant one, and that you get more gain from a resonant one. Am I quoting you correctly? You are sort of right on the first point if, by "better" you mean the op is using coax and desires to operate only on the resonant frequency of his antenna system and with no matching device in the line. But it is a long-proven fact that if the operator uses a feedline with considerably less loss, resonance of the system is much less of a factor. And in that case, resonance is not necessarily better than non-resonance. Our fascination and obsession with low SWR--whether promulgated by equipment manufacturers who wanted to sell us gear or by those who came to ham radio from other services without an understanding of standing waves and antenna theory--has led us to chase a number that does not necessarily have much bearing at all on how well an antenna system performs. A long doublet, cut close to resonance or longer on the lowest band for which it will be operated, fed with low-loss open wire line, matched to the output of a transmitter with some sort of a tuning device, will be at least very close to a resonant antenna in every respect on a wide variety of frequencies and bands. But as the operating frequency gets higher and the antenna remains the same length, the system will begin to show more and more gain in increasing numbers of nodes, with corresponding sharp null points. That makes the antenna system much better in some respects than the resonant version, even though it is not even close to resonant at a huge number of spots on the bands. It is still better than the resonant antenna, even in the nulls, because the coax-fed, no-matching-device system won't even begin to work at most of those frequencies! Again, as repeatedly discussed here, the reflected waves are not a serious factor in this setup because they are not lost--for the most part--in the feedline due to its low loss. Depending on the actual reactance at a frequency and the loss that does exist in the ladder line/window line/open wire line, it is probable that MOST of the reflected waves are eventually radiated into space. This is NOT theory. It is proven fact. And the "tuner?" If the matching device is of sufficient design, its loss will be more than tolerable and an easy trade-off for the convenience and effectiveness of having a single multi-band antenna system, efficiently useable...with GAIN...on many ham frequencies. Once again, I agree that there will be frequencies where, due to a lot of different factors, the reactance will be more than even the heftiest matching device can handle. Still, I'll take being able to have a potent signal on all 10 HF ham bands, even if there are 500 kHz of 160 and about 700 kHz of 10 meters that defy my matching device. Now, where do we disagree? 73, Don N4KC www.donkeith.com/n4kc.htm PS: Alan, you have done more for encouraging discourse on this great subject than anyone else I've seen in a long time! I hope that was your real intent!
Reply to a comment by : W4LGH on 2007-03-01

Ok..one last time, and lets see if I can say what I want to say so most will understand it. First, I never said I can disprove the known formulas, and I have said many times that are a great place to start! I have said that in the real world, there are many hidden varibles that change what the formula says. The changes could be minor, or they could be major, one has to try it and see what the actual results are. Many on here have eluded that one can hang a wire in the air, hook coax to it, run it into their shack and hook it to an antenna tuner, and TUNE the antenna into RESONANCE. This is simply NOT TRUE, and if you believe this you are only fooling yourself, and the tuner is a JOKE! Can you match the impedance of the coax in the shack, YES you can, but you are doing NOTHING to the antenna. Will this antenna radiate, YES, it will radiate something, but at a considerable loss. This can be PHYCIALLY PROVEN very easy with the aid of a SWR/WATT METER, and a simple Field Strength Meter. Now if you have a wire up for , I believe the freq was 3.500mhz and you want to tweak it with an inside antenna tuner for use on 3.850mhz, OK, but you shouldn't have to use a tuner to do this UNLESS you want to see a 1:1 match in your shack, the loss in the tuner could be greater than the loss @ 2:1 ratio. Some on here have eluded to the fact that for all practical purposes, one antenna can be used for all frequencies, when hooked to a tuner, YES it can, but the further away from the antennas resonant freq. the loss will continue to increase to a point where it becomes unuseable. Again, you are only fooling yourself. So One last time I will say...You CAN NOT TUNE the ANTENNA into resonance with coax hooked to a tuner in your shack. You are only matching the impedance between your radio and the tuner. I also never said you have to have 50 antenna cut to resonance to play radio. I DID say, using your wire matched with your tuner in your shack, and using a wire cut to the resonant freq. would have less loss, hence more gain, both transmit and receive. I also said that an antenna is reciprocal as to its transmit and receive in a perfect world, which we know does NOT exsist! Now, if you still do NOT understand where I am coming form, I am sorry, as I don't know how to explain it any better. There simply is NOT (1) one antenna fits all out there, and NO tuner in the world will make it so! Maybe my examples are to extreme for some of you to relate to HAM radio, but the principles are 100% the same, and are in all the books referenced here. If you can live with the losses, and you accept what you have @ the antenna thru the tuner, then so be it. I say there is something better than using the tuner and taking the losses. And the world isn't Flat, but it certainly isn't round either! And all LAWS/RULES/FORMULA's are not 100% black & white, there is always an area of gray, if for nothing else, a matter of Interpretation! 73 de W4LGH - Alan http://www.w4lgh.com
Reply to a comment by : W4EF on 2007-02-28

W4LGH wrote >>If what you and several others have been trying to make others believe, is true, then there is one (1) antenna to fit all, just plug in your tuner. NO..it doesn't work that way! And there is NO technical reference that has ever supported that theory.<< I agree completely, Alan. I don't think that anyone who knows anything about antennas will argue with what you have stated above. I am not sure who made the claims you referring to, as I don't recall seeing any such claims in this thread. What I take issue with is your claim that transmission line equations can't be used to accurately predict losses in a tuned system (mismatched antenna fed through a length of coaxial cable and tuned at the transmitter with a matching network). As long as you use the correct values for the complex propagation constant (alpha + jBeta), then they provide very accurate results as these equations can be readily derived directly from Maxwell's equations (James Clerk, not Walt)[See Kraus, J.D. "Electromagnetics", 3rd edition, chapter 10, section 2, pp 380 - 382. The complex propagation constant (alpha + j beta) derive directly from the velocity factor and loss of the cable. If you really think you have solid evidence that contradicts Maxwell's equations, then I suggest you submit your results to a peer reviewed journal (IEEE transactions on Antennas and Propagation, for example). If you are correct, then you probably will be flying home from Stockholm soon with a check for $1 million bucks in your hands (good luck). Nobody who knows anything about antennas is going to suggest that it's always a good idea to match any antenna through any length of coaxial cable using a tuner in the shack. For example, as most hams know, matching an 80 meter 1/2 wave dipole on 40 meters through a significant length of coaxial cable is very inefficient. This is easily predicted using the transmission line equations and typical input impedance for a center-fed 1 wavelength long dipole. In my experience, the predicted performance hit is in good agreement with on air performance. You will be able to work people, but you will be typically down 6 to 10dB from a 1/2 wave 40 meter dipole at the same height. On the other hand, matching an inverted-vee cut for 3.50 MHz in the shack with a matching network (aka Tuner) so that you can operate at 3.85 MHz with low VSWR is a pretty good tradeoff. I've done this through 100ft of RG-213 and through 1300ft of 7/8" hardline. In both cases, the antennas were just as competitive on SSB as they were on CW. Again this result is easily predicted using the transmission line equations or more conveniently a computer program like N6BV's TLW that is based on the transmission line equations. The short of it is this: it is misleading to claim that you can't use analytical tools to accurately predict feed system losses in amateur antenna installations. It is also misleading to claim that matching an antenna with a "tuner" through a length of coax is always a "joke". In some cases it is (equating "joke" with high system loss) and in some cases it is a sensible tradeoff. Simple analytical tools exist to make the determination. If you don't believe a dumb Eastern-Ohio hillbilly like me, ask an bonafide expert like Walt Maxwell, Dean Straw, or Roy Lewallen. Gotta get back to my day job now (it keeps spilling into my night time). 73, Mike W4EF.......................
Reply to a comment by : K1DA on 2007-02-28

But I want it to be clear that I don't agree with the "it must be resonant" theory. Not so. The SYSTEM must be configured so that the transmitter can generate proper power and that power can be sent through the feedline with low loss to whatever is out there as an antenna. Now if we want to talk about what different radiation PATTERNS different hunks of metal have, well that is an interesting topic UNRELATED to whether or not that chunk of metal is "resonant". The charts of radiation patterns of vetical antennas of different heights (some NON RESONANT lengths) show us how radiation patterns change but no where in those diagrms is "resonance a factor. As I said, YOU tell me how far away from the "resonant frequency" does the antenna loose it's magic and WHY ..__..
Reply to a comment by : K1DA on 2007-02-28

I agree. As I have said before WHEN does an antenna BECOME "nonresonant"??? How about 1 cycle off the design frequency unless you can tell me what extraordinary attempts have been made to increase bandwidth. Where does the now "nonresonant" antenna begin to show signs of signal radiation dropoff? How about when your 50 ohm transmitter can't deliver full output any more. And if compensation is introduced (what a misnomer "antenna tuner" is" ) and the feedline is low loss-- back to full radiation we go. Resonance and global warming, two of the most misunderstood concepts on the planet.
Reply to a comment by : K9IUQ on 2007-02-22

One TRUE statement was made, a RESONATE antenna will work BETTER than a NON_RESONATE antenna. People do NOT understand resonance ..................................................... The above is an false statement. An Antenna is resonant at ONLY ONE frequency. At any other frequency it is non-resonant. We all use non-resonant antennas (including you) on a daily basis. We make the antenna SYSTEM resonant with a tuner of one kind or another or live with SWR higher than 1:1. Agreed - the whole SYSTEM must be resonance -from the radio to the antenna. It makes little difference if the antenna itself is resonance or not.Many of the best performing wire antennas are non-resonant fed with open wire feeders and an antenna tuner. Also resonance of the SYSTEM has nothing to do with how well the antenna radiates. This is determined by MANY other factors. I have a wonderful Dummy load antenna under my desk that is resonant on all HF bands, however it doesnt seem to radiate very well since I haven't worked too many people with it. Please Pick Up an antenna Book like "Reflections" and learn the facts instead of trying to sell me 'some wonderful ocean front property in Arizona " K9IUQ
W4LGH2007-03-01
RE: Benchmarks
Don...here is a clip of what my first post stated....
"The idea of an antenna tuner hooked to an un-balanced line (coax) is absurd. The only thing you are tuning is the impedance at the shack end of the coax. The mis-match at the antenna still exsists and is still very REAL!! It may allow you to do something you couldn't without it, but you are only fooling yourself!"

Now after some 100+ post of everyone saying something else, its starting to turn around. Just like I said with mobile antennas, the matching device has to be at the antenna end to change the antenna. With the use of varible inductance at the antenna, you can change its resonant freq. I guess where I screwed up in the first post, as I assumed everyone would follow, but guess not, would have been to finsh the line "but you are only fooling yourself, if you think you are tuning the antenna!"

I have never said what was being done didn't work, I said there were induced losses. Yes when I say RESONANT is better, I am spreaking of 1 frequency, lets say 3850khz on a wire that is cut to that freq. This will work better than a 66' wire fed with 100' of rg8x coax into an antenna tuner, tuned so that the radio is putting out full power. This is where the better comes from. And I have seen this over and over, and these guys actually believe they are yuning their antenna. This simply is NOT true.

So I thank you Don, as so far you are starting to understand where I have been coming from from the begining. No, My intent was NOT to cause discontent
in this thread. Most of that was due to Stanley, simply not understanding, and taking cheap jabs at my knowledge. Over and over he has had some stupid comment to make about what I said, when he himself did not understand what I was saying.

So I am big enough to applogize for causing this discontent, but one can only take so many stupid jabs.

73 de W4LGH Alan
http://www.w4lgh.com
Reply to a comment by : N4KC on 2007-03-01

Alan, funny thing is, we all probably agree on more than we realize. I think it is just the degree to which you take a few of your ideas that are offputting to some. W4EF pointed out a perfect example. Using a tuner to try to match a long run of coax to a dipole that is way, way out of resonance will not give sterling performance. We agree on that. Using a tuner to get a match to a reasonable run of coax to stretch the usefulness of an antenna system that is not so far out of resonance is not "stupid" or "absurd." In the latter case, the loss of the standing waves in the coaxial feedline can range from negligible to tolerable, and it is an easy compromise for most of us to make if we are unable to erect an antenna that is resonant everywhere we desire to operate. I think you are admitting in your last post that you acknowledge that the formulae and theories we've been arguing about for the last week are actually valid and useful. Yes, results may vary, depending on many, many factors. And ultimately, the proof is in the pudding. That's why we put up antennas based on tried and true formulae, but then we test and measure and tweak. I'm not sure anyone here has said that you can "tune an antenna into resonance" with a "tuner." If they did, they are incorrect. An antenna system is resonant at a given frequency or it is not. You can change that point of resonance in some ways, such as by trimming or adding some wire, for example. A matching device, which can be what we typically call a "tuner," can be employed to allow the operator to match the output impedance of his rig to whatever the impedance of the antenna system is...on the desk, along the transmission line, or at the feedpoint of the antenna itself, all in an effort to use the antenna system on more than just the resonant frequency. Results can be good or they can be horrible, depending on several factors. I think we're mostly all still in agreement, right? Here's the biggie, though. You still maintain that a resonant antenna is "better" than a non-resonant one, and that you get more gain from a resonant one. Am I quoting you correctly? You are sort of right on the first point if, by "better" you mean the op is using coax and desires to operate only on the resonant frequency of his antenna system and with no matching device in the line. But it is a long-proven fact that if the operator uses a feedline with considerably less loss, resonance of the system is much less of a factor. And in that case, resonance is not necessarily better than non-resonance. Our fascination and obsession with low SWR--whether promulgated by equipment manufacturers who wanted to sell us gear or by those who came to ham radio from other services without an understanding of standing waves and antenna theory--has led us to chase a number that does not necessarily have much bearing at all on how well an antenna system performs. A long doublet, cut close to resonance or longer on the lowest band for which it will be operated, fed with low-loss open wire line, matched to the output of a transmitter with some sort of a tuning device, will be at least very close to a resonant antenna in every respect on a wide variety of frequencies and bands. But as the operating frequency gets higher and the antenna remains the same length, the system will begin to show more and more gain in increasing numbers of nodes, with corresponding sharp null points. That makes the antenna system much better in some respects than the resonant version, even though it is not even close to resonant at a huge number of spots on the bands. It is still better than the resonant antenna, even in the nulls, because the coax-fed, no-matching-device system won't even begin to work at most of those frequencies! Again, as repeatedly discussed here, the reflected waves are not a serious factor in this setup because they are not lost--for the most part--in the feedline due to its low loss. Depending on the actual reactance at a frequency and the loss that does exist in the ladder line/window line/open wire line, it is probable that MOST of the reflected waves are eventually radiated into space. This is NOT theory. It is proven fact. And the "tuner?" If the matching device is of sufficient design, its loss will be more than tolerable and an easy trade-off for the convenience and effectiveness of having a single multi-band antenna system, efficiently useable...with GAIN...on many ham frequencies. Once again, I agree that there will be frequencies where, due to a lot of different factors, the reactance will be more than even the heftiest matching device can handle. Still, I'll take being able to have a potent signal on all 10 HF ham bands, even if there are 500 kHz of 160 and about 700 kHz of 10 meters that defy my matching device. Now, where do we disagree? 73, Don N4KC www.donkeith.com/n4kc.htm PS: Alan, you have done more for encouraging discourse on this great subject than anyone else I've seen in a long time! I hope that was your real intent!
Reply to a comment by : W4LGH on 2007-03-01

Ok..one last time, and lets see if I can say what I want to say so most will understand it. First, I never said I can disprove the known formulas, and I have said many times that are a great place to start! I have said that in the real world, there are many hidden varibles that change what the formula says. The changes could be minor, or they could be major, one has to try it and see what the actual results are. Many on here have eluded that one can hang a wire in the air, hook coax to it, run it into their shack and hook it to an antenna tuner, and TUNE the antenna into RESONANCE. This is simply NOT TRUE, and if you believe this you are only fooling yourself, and the tuner is a JOKE! Can you match the impedance of the coax in the shack, YES you can, but you are doing NOTHING to the antenna. Will this antenna radiate, YES, it will radiate something, but at a considerable loss. This can be PHYCIALLY PROVEN very easy with the aid of a SWR/WATT METER, and a simple Field Strength Meter. Now if you have a wire up for , I believe the freq was 3.500mhz and you want to tweak it with an inside antenna tuner for use on 3.850mhz, OK, but you shouldn't have to use a tuner to do this UNLESS you want to see a 1:1 match in your shack, the loss in the tuner could be greater than the loss @ 2:1 ratio. Some on here have eluded to the fact that for all practical purposes, one antenna can be used for all frequencies, when hooked to a tuner, YES it can, but the further away from the antennas resonant freq. the loss will continue to increase to a point where it becomes unuseable. Again, you are only fooling yourself. So One last time I will say...You CAN NOT TUNE the ANTENNA into resonance with coax hooked to a tuner in your shack. You are only matching the impedance between your radio and the tuner. I also never said you have to have 50 antenna cut to resonance to play radio. I DID say, using your wire matched with your tuner in your shack, and using a wire cut to the resonant freq. would have less loss, hence more gain, both transmit and receive. I also said that an antenna is reciprocal as to its transmit and receive in a perfect world, which we know does NOT exsist! Now, if you still do NOT understand where I am coming form, I am sorry, as I don't know how to explain it any better. There simply is NOT (1) one antenna fits all out there, and NO tuner in the world will make it so! Maybe my examples are to extreme for some of you to relate to HAM radio, but the principles are 100% the same, and are in all the books referenced here. If you can live with the losses, and you accept what you have @ the antenna thru the tuner, then so be it. I say there is something better than using the tuner and taking the losses. And the world isn't Flat, but it certainly isn't round either! And all LAWS/RULES/FORMULA's are not 100% black & white, there is always an area of gray, if for nothing else, a matter of Interpretation! 73 de W4LGH - Alan http://www.w4lgh.com
Reply to a comment by : W4EF on 2007-02-28

W4LGH wrote >>If what you and several others have been trying to make others believe, is true, then there is one (1) antenna to fit all, just plug in your tuner. NO..it doesn't work that way! And there is NO technical reference that has ever supported that theory.<< I agree completely, Alan. I don't think that anyone who knows anything about antennas will argue with what you have stated above. I am not sure who made the claims you referring to, as I don't recall seeing any such claims in this thread. What I take issue with is your claim that transmission line equations can't be used to accurately predict losses in a tuned system (mismatched antenna fed through a length of coaxial cable and tuned at the transmitter with a matching network). As long as you use the correct values for the complex propagation constant (alpha + jBeta), then they provide very accurate results as these equations can be readily derived directly from Maxwell's equations (James Clerk, not Walt)[See Kraus, J.D. "Electromagnetics", 3rd edition, chapter 10, section 2, pp 380 - 382. The complex propagation constant (alpha + j beta) derive directly from the velocity factor and loss of the cable. If you really think you have solid evidence that contradicts Maxwell's equations, then I suggest you submit your results to a peer reviewed journal (IEEE transactions on Antennas and Propagation, for example). If you are correct, then you probably will be flying home from Stockholm soon with a check for $1 million bucks in your hands (good luck). Nobody who knows anything about antennas is going to suggest that it's always a good idea to match any antenna through any length of coaxial cable using a tuner in the shack. For example, as most hams know, matching an 80 meter 1/2 wave dipole on 40 meters through a significant length of coaxial cable is very inefficient. This is easily predicted using the transmission line equations and typical input impedance for a center-fed 1 wavelength long dipole. In my experience, the predicted performance hit is in good agreement with on air performance. You will be able to work people, but you will be typically down 6 to 10dB from a 1/2 wave 40 meter dipole at the same height. On the other hand, matching an inverted-vee cut for 3.50 MHz in the shack with a matching network (aka Tuner) so that you can operate at 3.85 MHz with low VSWR is a pretty good tradeoff. I've done this through 100ft of RG-213 and through 1300ft of 7/8" hardline. In both cases, the antennas were just as competitive on SSB as they were on CW. Again this result is easily predicted using the transmission line equations or more conveniently a computer program like N6BV's TLW that is based on the transmission line equations. The short of it is this: it is misleading to claim that you can't use analytical tools to accurately predict feed system losses in amateur antenna installations. It is also misleading to claim that matching an antenna with a "tuner" through a length of coax is always a "joke". In some cases it is (equating "joke" with high system loss) and in some cases it is a sensible tradeoff. Simple analytical tools exist to make the determination. If you don't believe a dumb Eastern-Ohio hillbilly like me, ask an bonafide expert like Walt Maxwell, Dean Straw, or Roy Lewallen. Gotta get back to my day job now (it keeps spilling into my night time). 73, Mike W4EF.......................
Reply to a comment by : K1DA on 2007-02-28

But I want it to be clear that I don't agree with the "it must be resonant" theory. Not so. The SYSTEM must be configured so that the transmitter can generate proper power and that power can be sent through the feedline with low loss to whatever is out there as an antenna. Now if we want to talk about what different radiation PATTERNS different hunks of metal have, well that is an interesting topic UNRELATED to whether or not that chunk of metal is "resonant". The charts of radiation patterns of vetical antennas of different heights (some NON RESONANT lengths) show us how radiation patterns change but no where in those diagrms is "resonance a factor. As I said, YOU tell me how far away from the "resonant frequency" does the antenna loose it's magic and WHY ..__..
Reply to a comment by : K1DA on 2007-02-28

I agree. As I have said before WHEN does an antenna BECOME "nonresonant"??? How about 1 cycle off the design frequency unless you can tell me what extraordinary attempts have been made to increase bandwidth. Where does the now "nonresonant" antenna begin to show signs of signal radiation dropoff? How about when your 50 ohm transmitter can't deliver full output any more. And if compensation is introduced (what a misnomer "antenna tuner" is" ) and the feedline is low loss-- back to full radiation we go. Resonance and global warming, two of the most misunderstood concepts on the planet.
Reply to a comment by : K9IUQ on 2007-02-22

One TRUE statement was made, a RESONATE antenna will work BETTER than a NON_RESONATE antenna. People do NOT understand resonance ..................................................... The above is an false statement. An Antenna is resonant at ONLY ONE frequency. At any other frequency it is non-resonant. We all use non-resonant antennas (including you) on a daily basis. We make the antenna SYSTEM resonant with a tuner of one kind or another or live with SWR higher than 1:1. Agreed - the whole SYSTEM must be resonance -from the radio to the antenna. It makes little difference if the antenna itself is resonance or not.Many of the best performing wire antennas are non-resonant fed with open wire feeders and an antenna tuner. Also resonance of the SYSTEM has nothing to do with how well the antenna radiates. This is determined by MANY other factors. I have a wonderful Dummy load antenna under my desk that is resonant on all HF bands, however it doesnt seem to radiate very well since I haven't worked too many people with it. Please Pick Up an antenna Book like "Reflections" and learn the facts instead of trying to sell me 'some wonderful ocean front property in Arizona " K9IUQ
N4KC2007-03-01
RE: Benchmarks
Alan, funny thing is, we all probably agree on more than we realize. I think it is just the degree to which you take a few of your ideas that are offputting to some. W4EF pointed out a perfect example. Using a tuner to try to match a long run of coax to a dipole that is way, way out of resonance will not give sterling performance. We agree on that. Using a tuner to get a match to a reasonable run of coax to stretch the usefulness of an antenna system that is not so far out of resonance is not "stupid" or "absurd." In the latter case, the loss of the standing waves in the coaxial feedline can range from negligible to tolerable, and it is an easy compromise for most of us to make if we are unable to erect an antenna that is resonant everywhere we desire to operate.

I think you are admitting in your last post that you acknowledge that the formulae and theories we've been arguing about for the last week are actually valid and useful. Yes, results may vary, depending on many, many factors. And ultimately, the proof is in the pudding. That's why we put up antennas based on tried and true formulae, but then we test and measure and tweak.

I'm not sure anyone here has said that you can "tune an antenna into resonance" with a "tuner." If they did, they are incorrect. An antenna system is resonant at a given frequency or it is not. You can change that point of resonance in some ways, such as by trimming or adding some wire, for example. A matching device, which can be what we typically call a "tuner," can be employed to allow the operator to match the output impedance of his rig to whatever the impedance of the antenna system is...on the desk, along the transmission line, or at the feedpoint of the antenna itself, all in an effort to use the antenna system on more than just the resonant frequency. Results can be good or they can be horrible, depending on several factors.

I think we're mostly all still in agreement, right?

Here's the biggie, though. You still maintain that a resonant antenna is "better" than a non-resonant one, and that you get more gain from a resonant one. Am I quoting you correctly?

You are sort of right on the first point if, by "better" you mean the op is using coax and desires to operate only on the resonant frequency of his antenna system and with no matching device in the line. But it is a long-proven fact that if the operator uses a feedline with considerably less loss, resonance of the system is much less of a factor. And in that case, resonance is not necessarily better than non-resonance.

Our fascination and obsession with low SWR--whether promulgated by equipment manufacturers who wanted to sell us gear or by those who came to ham radio from other services without an understanding of standing waves and antenna theory--has led us to chase a number that does not necessarily have much bearing at all on how well an antenna system performs. A long doublet, cut close to resonance or longer on the lowest band for which it will be operated, fed with low-loss open wire line, matched to the output of a transmitter with some sort of a tuning device, will be at least very close to a resonant antenna in every respect on a wide variety of frequencies and bands. But as the operating frequency gets higher and the antenna remains the same length, the system will begin to show more and more gain in increasing numbers of nodes, with corresponding sharp null points.

That makes the antenna system much better in some respects than the resonant version, even though it is not even close to resonant at a huge number of spots on the bands. It is still better than the resonant antenna, even in the nulls, because the coax-fed, no-matching-device system won't even begin to work at most of those frequencies!

Again, as repeatedly discussed here, the reflected waves are not a serious factor in this setup because they are not lost--for the most part--in the feedline due to its low loss. Depending on the actual reactance at a frequency and the loss that does exist in the ladder line/window line/open wire line, it is probable that MOST of the reflected waves are eventually radiated into space. This is NOT theory. It is proven fact. And the "tuner?" If the matching device is of sufficient design, its loss will be more than tolerable and an easy trade-off for the convenience and effectiveness of having a single multi-band antenna system, efficiently useable...with GAIN...on many ham frequencies.

Once again, I agree that there will be frequencies where, due to a lot of different factors, the reactance will be more than even the heftiest matching device can handle. Still, I'll take being able to have a potent signal on all 10 HF ham bands, even if there are 500 kHz of 160 and about 700 kHz of 10 meters that defy my matching device.

Now, where do we disagree?

73,

Don N4KC
www.donkeith.com/n4kc.htm

PS: Alan, you have done more for encouraging discourse on this great subject than anyone else I've seen in a long time! I hope that was your real intent!




Reply to a comment by : W4LGH on 2007-03-01

Ok..one last time, and lets see if I can say what I want to say so most will understand it. First, I never said I can disprove the known formulas, and I have said many times that are a great place to start! I have said that in the real world, there are many hidden varibles that change what the formula says. The changes could be minor, or they could be major, one has to try it and see what the actual results are. Many on here have eluded that one can hang a wire in the air, hook coax to it, run it into their shack and hook it to an antenna tuner, and TUNE the antenna into RESONANCE. This is simply NOT TRUE, and if you believe this you are only fooling yourself, and the tuner is a JOKE! Can you match the impedance of the coax in the shack, YES you can, but you are doing NOTHING to the antenna. Will this antenna radiate, YES, it will radiate something, but at a considerable loss. This can be PHYCIALLY PROVEN very easy with the aid of a SWR/WATT METER, and a simple Field Strength Meter. Now if you have a wire up for , I believe the freq was 3.500mhz and you want to tweak it with an inside antenna tuner for use on 3.850mhz, OK, but you shouldn't have to use a tuner to do this UNLESS you want to see a 1:1 match in your shack, the loss in the tuner could be greater than the loss @ 2:1 ratio. Some on here have eluded to the fact that for all practical purposes, one antenna can be used for all frequencies, when hooked to a tuner, YES it can, but the further away from the antennas resonant freq. the loss will continue to increase to a point where it becomes unuseable. Again, you are only fooling yourself. So One last time I will say...You CAN NOT TUNE the ANTENNA into resonance with coax hooked to a tuner in your shack. You are only matching the impedance between your radio and the tuner. I also never said you have to have 50 antenna cut to resonance to play radio. I DID say, using your wire matched with your tuner in your shack, and using a wire cut to the resonant freq. would have less loss, hence more gain, both transmit and receive. I also said that an antenna is reciprocal as to its transmit and receive in a perfect world, which we know does NOT exsist! Now, if you still do NOT understand where I am coming form, I am sorry, as I don't know how to explain it any better. There simply is NOT (1) one antenna fits all out there, and NO tuner in the world will make it so! Maybe my examples are to extreme for some of you to relate to HAM radio, but the principles are 100% the same, and are in all the books referenced here. If you can live with the losses, and you accept what you have @ the antenna thru the tuner, then so be it. I say there is something better than using the tuner and taking the losses. And the world isn't Flat, but it certainly isn't round either! And all LAWS/RULES/FORMULA's are not 100% black & white, there is always an area of gray, if for nothing else, a matter of Interpretation! 73 de W4LGH - Alan http://www.w4lgh.com
Reply to a comment by : W4EF on 2007-02-28

W4LGH wrote >>If what you and several others have been trying to make others believe, is true, then there is one (1) antenna to fit all, just plug in your tuner. NO..it doesn't work that way! And there is NO technical reference that has ever supported that theory.<< I agree completely, Alan. I don't think that anyone who knows anything about antennas will argue with what you have stated above. I am not sure who made the claims you referring to, as I don't recall seeing any such claims in this thread. What I take issue with is your claim that transmission line equations can't be used to accurately predict losses in a tuned system (mismatched antenna fed through a length of coaxial cable and tuned at the transmitter with a matching network). As long as you use the correct values for the complex propagation constant (alpha + jBeta), then they provide very accurate results as these equations can be readily derived directly from Maxwell's equations (James Clerk, not Walt)[See Kraus, J.D. "Electromagnetics", 3rd edition, chapter 10, section 2, pp 380 - 382. The complex propagation constant (alpha + j beta) derive directly from the velocity factor and loss of the cable. If you really think you have solid evidence that contradicts Maxwell's equations, then I suggest you submit your results to a peer reviewed journal (IEEE transactions on Antennas and Propagation, for example). If you are correct, then you probably will be flying home from Stockholm soon with a check for $1 million bucks in your hands (good luck). Nobody who knows anything about antennas is going to suggest that it's always a good idea to match any antenna through any length of coaxial cable using a tuner in the shack. For example, as most hams know, matching an 80 meter 1/2 wave dipole on 40 meters through a significant length of coaxial cable is very inefficient. This is easily predicted using the transmission line equations and typical input impedance for a center-fed 1 wavelength long dipole. In my experience, the predicted performance hit is in good agreement with on air performance. You will be able to work people, but you will be typically down 6 to 10dB from a 1/2 wave 40 meter dipole at the same height. On the other hand, matching an inverted-vee cut for 3.50 MHz in the shack with a matching network (aka Tuner) so that you can operate at 3.85 MHz with low VSWR is a pretty good tradeoff. I've done this through 100ft of RG-213 and through 1300ft of 7/8" hardline. In both cases, the antennas were just as competitive on SSB as they were on CW. Again this result is easily predicted using the transmission line equations or more conveniently a computer program like N6BV's TLW that is based on the transmission line equations. The short of it is this: it is misleading to claim that you can't use analytical tools to accurately predict feed system losses in amateur antenna installations. It is also misleading to claim that matching an antenna with a "tuner" through a length of coax is always a "joke". In some cases it is (equating "joke" with high system loss) and in some cases it is a sensible tradeoff. Simple analytical tools exist to make the determination. If you don't believe a dumb Eastern-Ohio hillbilly like me, ask an bonafide expert like Walt Maxwell, Dean Straw, or Roy Lewallen. Gotta get back to my day job now (it keeps spilling into my night time). 73, Mike W4EF.......................
Reply to a comment by : K1DA on 2007-02-28

But I want it to be clear that I don't agree with the "it must be resonant" theory. Not so. The SYSTEM must be configured so that the transmitter can generate proper power and that power can be sent through the feedline with low loss to whatever is out there as an antenna. Now if we want to talk about what different radiation PATTERNS different hunks of metal have, well that is an interesting topic UNRELATED to whether or not that chunk of metal is "resonant". The charts of radiation patterns of vetical antennas of different heights (some NON RESONANT lengths) show us how radiation patterns change but no where in those diagrms is "resonance a factor. As I said, YOU tell me how far away from the "resonant frequency" does the antenna loose it's magic and WHY ..__..
Reply to a comment by : K1DA on 2007-02-28

I agree. As I have said before WHEN does an antenna BECOME "nonresonant"??? How about 1 cycle off the design frequency unless you can tell me what extraordinary attempts have been made to increase bandwidth. Where does the now "nonresonant" antenna begin to show signs of signal radiation dropoff? How about when your 50 ohm transmitter can't deliver full output any more. And if compensation is introduced (what a misnomer "antenna tuner" is" ) and the feedline is low loss-- back to full radiation we go. Resonance and global warming, two of the most misunderstood concepts on the planet.
Reply to a comment by : K9IUQ on 2007-02-22

One TRUE statement was made, a RESONATE antenna will work BETTER than a NON_RESONATE antenna. People do NOT understand resonance ..................................................... The above is an false statement. An Antenna is resonant at ONLY ONE frequency. At any other frequency it is non-resonant. We all use non-resonant antennas (including you) on a daily basis. We make the antenna SYSTEM resonant with a tuner of one kind or another or live with SWR higher than 1:1. Agreed - the whole SYSTEM must be resonance -from the radio to the antenna. It makes little difference if the antenna itself is resonance or not.Many of the best performing wire antennas are non-resonant fed with open wire feeders and an antenna tuner. Also resonance of the SYSTEM has nothing to do with how well the antenna radiates. This is determined by MANY other factors. I have a wonderful Dummy load antenna under my desk that is resonant on all HF bands, however it doesnt seem to radiate very well since I haven't worked too many people with it. Please Pick Up an antenna Book like "Reflections" and learn the facts instead of trying to sell me 'some wonderful ocean front property in Arizona " K9IUQ
K9IUQ2007-03-01
Benchmarks
W4LGH says : Keep on with your personal attacks Stanley!

.....................................................
I have NEVER attacked you personally or attacked your character. BUT YOU have attacked ME PERSONALLY, called me vulgar names and continue to do so. And you are WAY out of line.....

I have attacked your views and opinions.


W4GLH says: So it only took you 45 years to upgrade from General to Extra



I am proud of my Extra class, like everyone I worked hard for it.BUT

Ham Class does not relate to intelligence or knowledge, you have proved this time and again..

Stan K9IUQ


W4LGH2007-03-01
RE: Benchmarks
Keep on with your personal attacks Stanley!
So it only took you 45 years to upgrade from General to Extra, ok, thats a little longer than most. Maybe in another 45 years, if you live that long, you'll start to understand what I am talking about! But probably not. It ok not to be technical, its a lot easier to let someone else figure it out and then copy it. Don't forget to DIP that Plate, so your TANK coil is RESONANT on that Vintage gear, we don't want ya pulling to much current an straining yourself.

I don't know why I keep on trying, you'll never get it. There are a lot of people on here that KNOW what I am talking about, and truely understand what I have been saying. However you continue to take cheap stabs at me, forcing me to come back at you, hence running most of the intelligent people away from here.

You continue to hang with your cronies, and do what you've alway done, and always get the same results and Life as you know it is GOOD!

Hang in there buddy, another 45 years and ya might just get it, but IT won't matter then!

This will be my LAST response to you Stanley. I am way past trying to get you to OPEN your EYES and MIND and actually learn something.

You can continue to jab at me if you wish, maybe it makes you feel like a young school boy again, maybe it makes you feel intelligent, who knows and who cares.

de W4LGH - Alan
http://www.w4lgh.com
Reply to a comment by : K9IUQ on 2007-03-01

W4LGH says: unless you consider your statement, "If tuners weren't any good the manufactures wouldn't build them into their radios." ....................................................... AL That isn't what I said and you know it. If you are going to quote me, quote me direct dont spin my words, I am really getting tired of it. Here is an example of cut and paste: W4LGH said "The idea of an antenna tuner hooked to an un-balanced line (coax) is absurd" And K9IUQ said: "If this was true we wouldn't have built-in antenna tuners in our rigs." ................................................... I assume you know how to cut and paste since You plagiarized Wiki. K9IUQ
KD2BD2007-03-01
RE: Benchmarks
W4LGH wrote:

> Now if you truely believe a tuner in your shack
> hooked to coax, will make a 75meter dipole resonant
> on 17meters, you have no idea what resonant is or
> means, and I can and will gladly show you "HARDCORE
> PROOF" that this is NOT so! PROOF that you can see
> with your OWN eyes!

I don't "believe" a tuner in your shack connected to a coax-fed dipole cut for 75 can be made to resonate on 17.

I know it for a fact.

A 5/8ths wave vertical isn't a "natural" resonant length for a radiator. Yet, combined with a proper resonating and impedance matching network, it can not only resonate where we want, it also provides some gain (vertical directivity) over a "naturally resonant" quarter wavelength antenna without the additional matching network.

So, go ahead. Start off simple. Demonstrate your "hardcore" proof that a 75-meter half-wave dipole fed with RG/8 through a well-designed tuner in the shack cannot become a resonant system on 18 MHz.

First, please begin with your definition of "resonant". And please stay away from Wikipedia this time. I want to hear YOUR definition, because as you stated earlier, textbooks are only good as a "starting point".

The floor is yours.


73, de John, KD2BD
Reply to a comment by : W4LGH on 2007-02-28

KD2BD wrote..."Standing Wave antennas, on the other hand, are resonant, including operating on 17 meters with a 75 meter coax fed dipole through a tuner. Adjusting the antenna tuner in the shack for a 50 ohm resistive output impedance in this case MAKES THE 75-METER ANTENNA SYSTEM RESONANT ON 17 METERS! And you were proven otherwise. Many times." ======== I fail to see where I have been PROVEN wrong at all. No proof has been offered, other than whats been written in books, and some standard math formulas, that we all know. And I have said, they are great for a starting point. Now if you truely believe a tuner in your shack hooked to coax, will make a 75meter dipole resonant on 17meters, you have no idea what resonant is or means, and I can and will gladly show you "HARDCORE PROOF" that this is NOT so! PROOF that you can see with your OWN eyes! Now will it make it work? To some degree, by fooling your transmitter to load into the tuner, which again, you could do with a 48" whip hooked to it. You can post until you are BLUE that this is SO, and again, I will SHOW you PROOF that is is NOT! If it was SO, there would be (1)antenna manufacture that would build 1 antenna the same for everything out there and you then buy your antenna tuner and hook it up to load it. This simply isn't so, and MILLIONS of $$$ are spent every year to improve on antenna design & efficiency. I just don't understand why hams want to continue to live in the dark ages. All of what I have said is also documented and can simply be seen, just looking around. You can load your 80m dipole up on 2meters if you have enough capacitance & inductance to tune out the reactance at the end of the coax, but it doesn't make it resoanant or efficient on 2 meters. If what you and several others have been trying to make other believe, there is one (1) antenna to fit all, just plug in your tuner. NO..it doesn't work that way! And there is NO technical refferance that has ever supported that theory. Broadcaster, cell phone companys and Hams have certainly wasted lots of money going on what you are trying to say. Wake up and smell the coffee man...Stop misleading the hams on here and stop trying to make me look like a fool, neither is correct. You simply CAN NOT TUNE the resonant frequency of the antenna by changing the reactance/impedance or resistance with a tuner in your shack hooked to un-balanced coax. 73 de W4LGH - Alan http://www.w4lgh.com
Reply to a comment by : N4SL on 2007-02-28

I Like Cake.
Reply to a comment by : ONAIR on 2007-02-22

Interesting point. So a resonant vertical dipole would then be a lot more efficient than a vertical that you would need to tune?
K9IUQ2007-03-01
Benchmarks
W4LGH says: unless you consider your statement, "If tuners weren't any good the manufactures wouldn't build them into their radios."
.......................................................

AL That isn't what I said and you know it. If you are going to quote me, quote me direct dont spin my words, I am really getting tired of it.


Here is an example of cut and paste:

W4LGH said "The idea of an antenna tuner hooked to an un-balanced line (coax) is absurd"

And K9IUQ said:

"If this was true we wouldn't have built-in antenna tuners in our rigs."

...................................................

I assume you know how to cut and paste since You plagiarized Wiki.

K9IUQ








K9IUQ2007-03-01
Benchmarks
W4LGH says: Keep hanging on to others coat tails

Unlike you Al I know my limitations. Which is why I hold on to Walter Maxwell "Reflections", ARRL Antenna handbook,Eznec Software, AND other smart hams coat tails like KD2BD, W4EF,N4KC, N9OX, W6TH ,AA4PB,Ke4ZHN, W8JI,K0IZ,KA0GKT,W0IVJ,N0EW,K6IOU, And many other hams on this thread.

I also hold onto (in)famous Kurt N. Sterba's musings......

ALL of the above have shown you to be wrong, you just arern't smart enough to see it....

Sad, so sad
Stan K9IUQ
W4LGH2007-03-01
RE: Benchmarks
Stan K9IUQ writes... "HEHEHEHEHEHE Really Al, you are WAY too funny. Rolling on the Floor LMAO"
==============
Enjoy yourself Stan...just remember he who laughs last, laughs the best! I haven't seen you add much technical knowledge to this thread, unless you consider your statement, "If tuners weren't any good the manufactures wouldn't build them into their radios." They laughed at the Steamboat, and the most sofisticated nuclear ships out there today are still powered by steam, They laughed at Edison, Westinghouse, hell they even laughed when we said we were going to moon, but who had the last laugh. Laughing like this only shows ones ignorance, or inability to comprehend, or at the very least, ones unwillingness to accept or learn. So keep on laughing Stanley! Keep hanging on to others coat tails!

My statements come from real world experience, some from textbooks over the years, and a lot of common sense to be able to apply rules and real world when needed.

Laugh it up Stan!

73 de W4LGH - Alan
http://www.w4lgh.com
Reply to a comment by : W4LGH on 2007-03-01

Ok..one last time, and lets see if I can say what I want to say so most will understand it. First, I never said I can disprove the known formulas, and I have said many times that are a great place to start! I have said that in the real world, there are many hidden varibles that change what the formula says. The changes could be minor, or they could be major, one has to try it and see what the actual results are. Many on here have eluded that one can hang a wire in the air, hook coax to it, run it into their shack and hook it to an antenna tuner, and TUNE the antenna into RESONANCE. This is simply NOT TRUE, and if you believe this you are only fooling yourself, and the tuner is a JOKE! Can you match the impedance of the coax in the shack, YES you can, but you are doing NOTHING to the antenna. Will this antenna radiate, YES, it will radiate something, but at a considerable loss. This can be PHYCIALLY PROVEN very easy with the aid of a SWR/WATT METER, and a simple Field Strength Meter. Now if you have a wire up for , I believe the freq was 3.500mhz and you want to tweak it with an inside antenna tuner for use on 3.850mhz, OK, but you shouldn't have to use a tuner to do this UNLESS you want to see a 1:1 match in your shack, the loss in the tuner could be greater than the loss @ 2:1 ratio. Some on here have eluded to the fact that for all practical purposes, one antenna can be used for all frequencies, when hooked to a tuner, YES it can, but the further away from the antennas resonant freq. the loss will continue to increase to a point where it becomes unuseable. Again, you are only fooling yourself. So One last time I will say...You CAN NOT TUNE the ANTENNA into resonance with coax hooked to a tuner in your shack. You are only matching the impedance between your radio and the tuner. I also never said you have to have 50 antenna cut to resonance to play radio. I DID say, using your wire matched with your tuner in your shack, and using a wire cut to the resonant freq. would have less loss, hence more gain, both transmit and receive. I also said that an antenna is reciprocal as to its transmit and receive in a perfect world, which we know does NOT exsist! Now, if you still do NOT understand where I am coming form, I am sorry, as I don't know how to explain it any better. There simply is NOT (1) one antenna fits all out there, and NO tuner in the world will make it so! Maybe my examples are to extreme for some of you to relate to HAM radio, but the principles are 100% the same, and are in all the books referenced here. If you can live with the losses, and you accept what you have @ the antenna thru the tuner, then so be it. I say there is something better than using the tuner and taking the losses. And the world isn't Flat, but it certainly isn't round either! And all LAWS/RULES/FORMULA's are not 100% black & white, there is always an area of gray, if for nothing else, a matter of Interpretation! 73 de W4LGH - Alan http://www.w4lgh.com
Reply to a comment by : W4EF on 2007-02-28

W4LGH wrote >>If what you and several others have been trying to make others believe, is true, then there is one (1) antenna to fit all, just plug in your tuner. NO..it doesn't work that way! And there is NO technical reference that has ever supported that theory.<< I agree completely, Alan. I don't think that anyone who knows anything about antennas will argue with what you have stated above. I am not sure who made the claims you referring to, as I don't recall seeing any such claims in this thread. What I take issue with is your claim that transmission line equations can't be used to accurately predict losses in a tuned system (mismatched antenna fed through a length of coaxial cable and tuned at the transmitter with a matching network). As long as you use the correct values for the complex propagation constant (alpha + jBeta), then they provide very accurate results as these equations can be readily derived directly from Maxwell's equations (James Clerk, not Walt)[See Kraus, J.D. "Electromagnetics", 3rd edition, chapter 10, section 2, pp 380 - 382. The complex propagation constant (alpha + j beta) derive directly from the velocity factor and loss of the cable. If you really think you have solid evidence that contradicts Maxwell's equations, then I suggest you submit your results to a peer reviewed journal (IEEE transactions on Antennas and Propagation, for example). If you are correct, then you probably will be flying home from Stockholm soon with a check for $1 million bucks in your hands (good luck). Nobody who knows anything about antennas is going to suggest that it's always a good idea to match any antenna through any length of coaxial cable using a tuner in the shack. For example, as most hams know, matching an 80 meter 1/2 wave dipole on 40 meters through a significant length of coaxial cable is very inefficient. This is easily predicted using the transmission line equations and typical input impedance for a center-fed 1 wavelength long dipole. In my experience, the predicted performance hit is in good agreement with on air performance. You will be able to work people, but you will be typically down 6 to 10dB from a 1/2 wave 40 meter dipole at the same height. On the other hand, matching an inverted-vee cut for 3.50 MHz in the shack with a matching network (aka Tuner) so that you can operate at 3.85 MHz with low VSWR is a pretty good tradeoff. I've done this through 100ft of RG-213 and through 1300ft of 7/8" hardline. In both cases, the antennas were just as competitive on SSB as they were on CW. Again this result is easily predicted using the transmission line equations or more conveniently a computer program like N6BV's TLW that is based on the transmission line equations. The short of it is this: it is misleading to claim that you can't use analytical tools to accurately predict feed system losses in amateur antenna installations. It is also misleading to claim that matching an antenna with a "tuner" through a length of coax is always a "joke". In some cases it is (equating "joke" with high system loss) and in some cases it is a sensible tradeoff. Simple analytical tools exist to make the determination. If you don't believe a dumb Eastern-Ohio hillbilly like me, ask an bonafide expert like Walt Maxwell, Dean Straw, or Roy Lewallen. Gotta get back to my day job now (it keeps spilling into my night time). 73, Mike W4EF.......................
Reply to a comment by : K1DA on 2007-02-28

But I want it to be clear that I don't agree with the "it must be resonant" theory. Not so. The SYSTEM must be configured so that the transmitter can generate proper power and that power can be sent through the feedline with low loss to whatever is out there as an antenna. Now if we want to talk about what different radiation PATTERNS different hunks of metal have, well that is an interesting topic UNRELATED to whether or not that chunk of metal is "resonant". The charts of radiation patterns of vetical antennas of different heights (some NON RESONANT lengths) show us how radiation patterns change but no where in those diagrms is "resonance a factor. As I said, YOU tell me how far away from the "resonant frequency" does the antenna loose it's magic and WHY ..__..
Reply to a comment by : K1DA on 2007-02-28

I agree. As I have said before WHEN does an antenna BECOME "nonresonant"??? How about 1 cycle off the design frequency unless you can tell me what extraordinary attempts have been made to increase bandwidth. Where does the now "nonresonant" antenna begin to show signs of signal radiation dropoff? How about when your 50 ohm transmitter can't deliver full output any more. And if compensation is introduced (what a misnomer "antenna tuner" is" ) and the feedline is low loss-- back to full radiation we go. Resonance and global warming, two of the most misunderstood concepts on the planet.
Reply to a comment by : K9IUQ on 2007-02-22

One TRUE statement was made, a RESONATE antenna will work BETTER than a NON_RESONATE antenna. People do NOT understand resonance ..................................................... The above is an false statement. An Antenna is resonant at ONLY ONE frequency. At any other frequency it is non-resonant. We all use non-resonant antennas (including you) on a daily basis. We make the antenna SYSTEM resonant with a tuner of one kind or another or live with SWR higher than 1:1. Agreed - the whole SYSTEM must be resonance -from the radio to the antenna. It makes little difference if the antenna itself is resonance or not.Many of the best performing wire antennas are non-resonant fed with open wire feeders and an antenna tuner. Also resonance of the SYSTEM has nothing to do with how well the antenna radiates. This is determined by MANY other factors. I have a wonderful Dummy load antenna under my desk that is resonant on all HF bands, however it doesnt seem to radiate very well since I haven't worked too many people with it. Please Pick Up an antenna Book like "Reflections" and learn the facts instead of trying to sell me 'some wonderful ocean front property in Arizona " K9IUQ
W4LGH2007-03-01
RE: Benchmarks
Ok..one last time, and lets see if I can say what I want to say so most will understand it. First, I never said I can disprove the known formulas, and I have said many times that are a great place to start!
I have said that in the real world, there are many hidden varibles that change what the formula says. The changes could be minor, or they could be major, one has to try it and see what the actual results are.

Many on here have eluded that one can hang a wire in the air, hook coax to it, run it into their shack and hook it to an antenna tuner, and TUNE the antenna into RESONANCE. This is simply NOT TRUE, and if you believe this you are only fooling yourself, and the tuner is a JOKE! Can you match the impedance of the coax in the shack, YES you can, but you are doing NOTHING to the antenna. Will this antenna radiate, YES, it will radiate something, but at a considerable loss. This can be PHYCIALLY PROVEN very easy with the aid of a SWR/WATT METER, and a simple Field Strength Meter.

Now if you have a wire up for , I believe the freq was 3.500mhz and you want to tweak it with an inside antenna tuner for use on 3.850mhz, OK, but you shouldn't have to use a tuner to do this UNLESS you want to see a 1:1 match in your shack, the loss in the tuner could be greater than the loss @ 2:1 ratio.

Some on here have eluded to the fact that for all practical purposes, one antenna can be used for all frequencies, when hooked to a tuner, YES it can, but the further away from the antennas resonant freq. the loss will continue to increase to a point where it becomes unuseable. Again, you are only fooling yourself.

So One last time I will say...You CAN NOT TUNE the ANTENNA into resonance with coax hooked to a tuner in your shack. You are only matching the impedance between your radio and the tuner.

I also never said you have to have 50 antenna cut to resonance to play radio. I DID say, using your wire matched with your tuner in your shack, and using a wire cut to the resonant freq. would have less loss, hence more gain, both transmit and receive. I also said that an antenna is reciprocal as to its transmit and receive in a perfect world, which we know does NOT exsist!

Now, if you still do NOT understand where I am coming form, I am sorry, as I don't know how to explain it any better. There simply is NOT (1) one antenna fits all out there, and NO tuner in the world will make it so! Maybe my examples are to extreme for some of you to relate to HAM radio, but the principles are 100% the same, and are in all the books referenced here.

If you can live with the losses, and you accept what you have @ the antenna thru the tuner, then so be it. I say there is something better than using the tuner and taking the losses.

And the world isn't Flat, but it certainly isn't round either! And all LAWS/RULES/FORMULA's are not 100% black & white, there is always an area of gray, if for nothing else, a matter of Interpretation!

73 de W4LGH - Alan
http://www.w4lgh.com
Reply to a comment by : W4EF on 2007-02-28

W4LGH wrote >>If what you and several others have been trying to make others believe, is true, then there is one (1) antenna to fit all, just plug in your tuner. NO..it doesn't work that way! And there is NO technical reference that has ever supported that theory.<< I agree completely, Alan. I don't think that anyone who knows anything about antennas will argue with what you have stated above. I am not sure who made the claims you referring to, as I don't recall seeing any such claims in this thread. What I take issue with is your claim that transmission line equations can't be used to accurately predict losses in a tuned system (mismatched antenna fed through a length of coaxial cable and tuned at the transmitter with a matching network). As long as you use the correct values for the complex propagation constant (alpha + jBeta), then they provide very accurate results as these equations can be readily derived directly from Maxwell's equations (James Clerk, not Walt)[See Kraus, J.D. "Electromagnetics", 3rd edition, chapter 10, section 2, pp 380 - 382. The complex propagation constant (alpha + j beta) derive directly from the velocity factor and loss of the cable. If you really think you have solid evidence that contradicts Maxwell's equations, then I suggest you submit your results to a peer reviewed journal (IEEE transactions on Antennas and Propagation, for example). If you are correct, then you probably will be flying home from Stockholm soon with a check for $1 million bucks in your hands (good luck). Nobody who knows anything about antennas is going to suggest that it's always a good idea to match any antenna through any length of coaxial cable using a tuner in the shack. For example, as most hams know, matching an 80 meter 1/2 wave dipole on 40 meters through a significant length of coaxial cable is very inefficient. This is easily predicted using the transmission line equations and typical input impedance for a center-fed 1 wavelength long dipole. In my experience, the predicted performance hit is in good agreement with on air performance. You will be able to work people, but you will be typically down 6 to 10dB from a 1/2 wave 40 meter dipole at the same height. On the other hand, matching an inverted-vee cut for 3.50 MHz in the shack with a matching network (aka Tuner) so that you can operate at 3.85 MHz with low VSWR is a pretty good tradeoff. I've done this through 100ft of RG-213 and through 1300ft of 7/8" hardline. In both cases, the antennas were just as competitive on SSB as they were on CW. Again this result is easily predicted using the transmission line equations or more conveniently a computer program like N6BV's TLW that is based on the transmission line equations. The short of it is this: it is misleading to claim that you can't use analytical tools to accurately predict feed system losses in amateur antenna installations. It is also misleading to claim that matching an antenna with a "tuner" through a length of coax is always a "joke". In some cases it is (equating "joke" with high system loss) and in some cases it is a sensible tradeoff. Simple analytical tools exist to make the determination. If you don't believe a dumb Eastern-Ohio hillbilly like me, ask an bonafide expert like Walt Maxwell, Dean Straw, or Roy Lewallen. Gotta get back to my day job now (it keeps spilling into my night time). 73, Mike W4EF.......................
Reply to a comment by : K1DA on 2007-02-28

But I want it to be clear that I don't agree with the "it must be resonant" theory. Not so. The SYSTEM must be configured so that the transmitter can generate proper power and that power can be sent through the feedline with low loss to whatever is out there as an antenna. Now if we want to talk about what different radiation PATTERNS different hunks of metal have, well that is an interesting topic UNRELATED to whether or not that chunk of metal is "resonant". The charts of radiation patterns of vetical antennas of different heights (some NON RESONANT lengths) show us how radiation patterns change but no where in those diagrms is "resonance a factor. As I said, YOU tell me how far away from the "resonant frequency" does the antenna loose it's magic and WHY ..__..
Reply to a comment by : K1DA on 2007-02-28

I agree. As I have said before WHEN does an antenna BECOME "nonresonant"??? How about 1 cycle off the design frequency unless you can tell me what extraordinary attempts have been made to increase bandwidth. Where does the now "nonresonant" antenna begin to show signs of signal radiation dropoff? How about when your 50 ohm transmitter can't deliver full output any more. And if compensation is introduced (what a misnomer "antenna tuner" is" ) and the feedline is low loss-- back to full radiation we go. Resonance and global warming, two of the most misunderstood concepts on the planet.
Reply to a comment by : K9IUQ on 2007-02-22

One TRUE statement was made, a RESONATE antenna will work BETTER than a NON_RESONATE antenna. People do NOT understand resonance ..................................................... The above is an false statement. An Antenna is resonant at ONLY ONE frequency. At any other frequency it is non-resonant. We all use non-resonant antennas (including you) on a daily basis. We make the antenna SYSTEM resonant with a tuner of one kind or another or live with SWR higher than 1:1. Agreed - the whole SYSTEM must be resonance -from the radio to the antenna. It makes little difference if the antenna itself is resonance or not.Many of the best performing wire antennas are non-resonant fed with open wire feeders and an antenna tuner. Also resonance of the SYSTEM has nothing to do with how well the antenna radiates. This is determined by MANY other factors. I have a wonderful Dummy load antenna under my desk that is resonant on all HF bands, however it doesnt seem to radiate very well since I haven't worked too many people with it. Please Pick Up an antenna Book like "Reflections" and learn the facts instead of trying to sell me 'some wonderful ocean front property in Arizona " K9IUQ
W8JII2007-03-01
RE: Benchmarks
Where's W8JI when you need him???????????Oh well, maybe no one will believe him either.
Reply to a comment by : K9IUQ on 2007-03-01

W4LGH continues making us laugh: I fail to see where I have been PROVEN wrong at all. No proof has been offered, other than whats been written in books, ......................................................... HEHEHEHEHEHE Really Al, you are WAY too funny. Rolling on the Floor LMAO Stan K9IUQ
K9IUQ2007-03-01
Benchmarks
W4LGH continues making us laugh: I fail to see where I have been PROVEN wrong at all. No proof has been offered, other than whats been written in books,

.........................................................

HEHEHEHEHEHE

Really Al, you are WAY too funny.

Rolling on the Floor LMAO

Stan K9IUQ
W4EF2007-02-28
RE: Benchmarks
W4LGH wrote

>>If what you and several others have been trying to make others believe, is true, then there is one (1) antenna to fit all, just plug in your tuner. NO..it doesn't work that way! And there is NO technical reference that has ever supported that theory.<<

I agree completely, Alan. I don't think that anyone who knows anything about antennas will argue with what you have stated above. I am not sure who made the claims you referring to, as I don't recall seeing any such claims in this thread.

What I take issue with is your claim that transmission line equations can't be used to accurately predict losses in a tuned system (mismatched antenna fed through a length of coaxial cable and tuned at the transmitter with a matching network). As long as you use the correct values for the complex propagation constant (alpha + jBeta), then they provide very accurate results as these equations can be readily derived directly from Maxwell's equations (James Clerk, not Walt)[See Kraus, J.D. "Electromagnetics", 3rd edition, chapter 10, section 2, pp 380 - 382. The complex propagation constant (alpha + j beta) derive directly from the velocity factor and loss of the cable. If you really think you have solid evidence that contradicts Maxwell's equations, then I suggest you submit your results to a peer reviewed journal (IEEE transactions on Antennas and Propagation, for example). If you are correct, then you probably will be flying home from Stockholm soon with a check for $1 million bucks in your hands (good luck).

Nobody who knows anything about antennas is going to suggest that it's always a good idea to match any antenna through any length of coaxial cable using a tuner in the shack. For example, as most hams know, matching an 80 meter 1/2 wave dipole on 40 meters through a significant length of coaxial cable is very inefficient. This is easily predicted using the transmission line equations and typical input impedance for a center-fed 1 wavelength long dipole. In my experience, the predicted performance hit is in good agreement with on air performance. You will be able to work people, but you will be typically down 6 to 10dB from a 1/2 wave 40 meter dipole at the same height. On the other hand, matching an inverted-vee cut for 3.50 MHz in the shack with a matching network (aka Tuner) so that you can operate at 3.85 MHz with low VSWR is a pretty good tradeoff. I've done this through 100ft of RG-213 and through 1300ft of 7/8" hardline. In both cases, the antennas were just as competitive on SSB as they were on CW. Again this result is easily predicted using the transmission line equations or more conveniently a computer program like N6BV's TLW that is based on the transmission line equations.

The short of it is this: it is misleading to claim that you can't use analytical tools to accurately predict feed system losses in amateur antenna installations. It is also misleading to claim that matching an antenna with a "tuner" through a length of coax is always a "joke". In some cases it is (equating "joke" with high system loss) and in some cases it is a sensible tradeoff. Simple analytical tools exist to make the determination.

If you don't believe a dumb Eastern-Ohio hillbilly like me, ask an bonafide expert like Walt Maxwell, Dean Straw, or Roy Lewallen.

Gotta get back to my day job now (it keeps spilling into my night time).

73, Mike W4EF.......................
Reply to a comment by : K1DA on 2007-02-28

But I want it to be clear that I don't agree with the "it must be resonant" theory. Not so. The SYSTEM must be configured so that the transmitter can generate proper power and that power can be sent through the feedline with low loss to whatever is out there as an antenna. Now if we want to talk about what different radiation PATTERNS different hunks of metal have, well that is an interesting topic UNRELATED to whether or not that chunk of metal is "resonant". The charts of radiation patterns of vetical antennas of different heights (some NON RESONANT lengths) show us how radiation patterns change but no where in those diagrms is "resonance a factor. As I said, YOU tell me how far away from the "resonant frequency" does the antenna loose it's magic and WHY ..__..
Reply to a comment by : K1DA on 2007-02-28

I agree. As I have said before WHEN does an antenna BECOME "nonresonant"??? How about 1 cycle off the design frequency unless you can tell me what extraordinary attempts have been made to increase bandwidth. Where does the now "nonresonant" antenna begin to show signs of signal radiation dropoff? How about when your 50 ohm transmitter can't deliver full output any more. And if compensation is introduced (what a misnomer "antenna tuner" is" ) and the feedline is low loss-- back to full radiation we go. Resonance and global warming, two of the most misunderstood concepts on the planet.
Reply to a comment by : K9IUQ on 2007-02-22

One TRUE statement was made, a RESONATE antenna will work BETTER than a NON_RESONATE antenna. People do NOT understand resonance ..................................................... The above is an false statement. An Antenna is resonant at ONLY ONE frequency. At any other frequency it is non-resonant. We all use non-resonant antennas (including you) on a daily basis. We make the antenna SYSTEM resonant with a tuner of one kind or another or live with SWR higher than 1:1. Agreed - the whole SYSTEM must be resonance -from the radio to the antenna. It makes little difference if the antenna itself is resonance or not.Many of the best performing wire antennas are non-resonant fed with open wire feeders and an antenna tuner. Also resonance of the SYSTEM has nothing to do with how well the antenna radiates. This is determined by MANY other factors. I have a wonderful Dummy load antenna under my desk that is resonant on all HF bands, however it doesnt seem to radiate very well since I haven't worked too many people with it. Please Pick Up an antenna Book like "Reflections" and learn the facts instead of trying to sell me 'some wonderful ocean front property in Arizona " K9IUQ
K1DA2007-02-28
RE: Benchmarks
But I want it to be clear that I don't agree with the "it must be resonant" theory. Not so. The SYSTEM must be configured so that the transmitter can generate proper power and that power can be sent through the feedline with low loss to whatever is out there as an antenna. Now if we want to talk about what different radiation PATTERNS different hunks of metal have, well that is an interesting topic UNRELATED to whether or not that chunk of metal is "resonant". The charts of radiation patterns of vetical antennas of different heights (some NON RESONANT lengths) show us how radiation patterns change
but no where in those diagrms is "resonance a factor. As I said, YOU tell me how far away from the "resonant frequency" does the antenna loose it's magic and WHY ..__..
Reply to a comment by : K1DA on 2007-02-28

I agree. As I have said before WHEN does an antenna BECOME "nonresonant"??? How about 1 cycle off the design frequency unless you can tell me what extraordinary attempts have been made to increase bandwidth. Where does the now "nonresonant" antenna begin to show signs of signal radiation dropoff? How about when your 50 ohm transmitter can't deliver full output any more. And if compensation is introduced (what a misnomer "antenna tuner" is" ) and the feedline is low loss-- back to full radiation we go. Resonance and global warming, two of the most misunderstood concepts on the planet.
Reply to a comment by : K9IUQ on 2007-02-22

One TRUE statement was made, a RESONATE antenna will work BETTER than a NON_RESONATE antenna. People do NOT understand resonance ..................................................... The above is an false statement. An Antenna is resonant at ONLY ONE frequency. At any other frequency it is non-resonant. We all use non-resonant antennas (including you) on a daily basis. We make the antenna SYSTEM resonant with a tuner of one kind or another or live with SWR higher than 1:1. Agreed - the whole SYSTEM must be resonance -from the radio to the antenna. It makes little difference if the antenna itself is resonance or not.Many of the best performing wire antennas are non-resonant fed with open wire feeders and an antenna tuner. Also resonance of the SYSTEM has nothing to do with how well the antenna radiates. This is determined by MANY other factors. I have a wonderful Dummy load antenna under my desk that is resonant on all HF bands, however it doesnt seem to radiate very well since I haven't worked too many people with it. Please Pick Up an antenna Book like "Reflections" and learn the facts instead of trying to sell me 'some wonderful ocean front property in Arizona " K9IUQ
K1DA2007-02-28
RE: Benchmarks
I agree. As I have said before WHEN does an antenna BECOME "nonresonant"??? How about 1 cycle off the design frequency unless you can tell me what extraordinary attempts have been made to increase bandwidth. Where does the now "nonresonant" antenna
begin to show signs of signal radiation dropoff? How about when your 50 ohm transmitter can't deliver full output any more. And if compensation is introduced (what a misnomer "antenna tuner" is" ) and the feedline is low loss-- back to full radiation we go.
Resonance and global warming, two of the most misunderstood concepts on the planet.
Reply to a comment by : K9IUQ on 2007-02-22

One TRUE statement was made, a RESONATE antenna will work BETTER than a NON_RESONATE antenna. People do NOT understand resonance ..................................................... The above is an false statement. An Antenna is resonant at ONLY ONE frequency. At any other frequency it is non-resonant. We all use non-resonant antennas (including you) on a daily basis. We make the antenna SYSTEM resonant with a tuner of one kind or another or live with SWR higher than 1:1. Agreed - the whole SYSTEM must be resonance -from the radio to the antenna. It makes little difference if the antenna itself is resonance or not.Many of the best performing wire antennas are non-resonant fed with open wire feeders and an antenna tuner. Also resonance of the SYSTEM has nothing to do with how well the antenna radiates. This is determined by MANY other factors. I have a wonderful Dummy load antenna under my desk that is resonant on all HF bands, however it doesnt seem to radiate very well since I haven't worked too many people with it. Please Pick Up an antenna Book like "Reflections" and learn the facts instead of trying to sell me 'some wonderful ocean front property in Arizona " K9IUQ
W4LGH2007-02-28
RE: Benchmarks
KD2BD wrote..."Standing Wave antennas, on the other hand, are resonant, including operating on 17 meters with a 75 meter coax fed dipole through a tuner.
Adjusting the antenna tuner in the shack for a 50 ohm resistive output impedance in this case MAKES THE 75-METER ANTENNA SYSTEM RESONANT ON 17 METERS! And you were proven otherwise. Many times."
========
I fail to see where I have been PROVEN wrong at all. No proof has been offered, other than whats been written in books, and some standard math formulas, that we all know. And I have said, they are great for a starting point. Now if you truely believe a tuner in your shack hooked to coax, will make a 75meter dipole resonant on 17meters, you have no idea what resonant is or means, and I can and will gladly show you "HARDCORE PROOF" that this is NOT so! PROOF that you can see with your OWN eyes! Now will it make it work? To some degree, by fooling your transmitter to load into the tuner, which again, you could do with a 48" whip hooked to it. You can post until you are BLUE that this is SO, and again, I will SHOW you PROOF that is is NOT! If it was SO, there would be (1)antenna manufacture that would build 1 antenna the same for everything out there and you then buy your antenna tuner and hook it up to load it. This simply isn't so, and MILLIONS of $$$ are spent every year to improve on antenna design & efficiency. I just don't understand why hams want to continue to live in the dark ages. All of what I have said is also documented and can simply be seen, just looking around. You can load your 80m dipole up on 2meters if you have enough capacitance & inductance to tune out the reactance at the end of the coax, but it doesn't make it resoanant
or efficient on 2 meters.

If what you and several others have been trying to make other believe, there is one (1) antenna to fit all, just plug in your tuner. NO..it doesn't work that way! And there is NO technical refferance that has ever supported that theory. Broadcaster, cell phone companys and Hams have certainly wasted lots of money going on what you are trying to say.

Wake up and smell the coffee man...Stop misleading the hams on here and stop trying to make me look like a fool, neither is correct.

You simply CAN NOT TUNE the resonant frequency of the antenna by changing the reactance/impedance or resistance with a tuner in your shack hooked to un-balanced coax.

73 de W4LGH - Alan
http://www.w4lgh.com
Reply to a comment by : N4SL on 2007-02-28

I Like Cake.
Reply to a comment by : ONAIR on 2007-02-22

Interesting point. So a resonant vertical dipole would then be a lot more efficient than a vertical that you would need to tune?
WB5PLJ2007-02-28
RE: Benchmarks
Do you people not understand the difference between Subjective and Objective? between qualitative and quantitative?

I hurt now!


And I like Cake too..
Reply to a comment by : KD2BD on 2007-02-28

W4LGH wrote: > > I have said that a resonant antenna was a better > antenna, The only non-resonant antennas you are likely to find in wide Amateur Radio use are the Beverage and the Rhombic. These are part of a family of radiators known as Traveling Wave Antennas. Standing Wave antennas, on the other hand, are resonant, including operating on 17 meters with a 75 meter coax fed dipole through a tuner. Adjusting the antenna tuner in the shack for a 50 ohm resistive output impedance in this case MAKES THE 75-METER ANTENNA SYSTEM RESONANT ON 17 METERS! That's not "just a theory". It's reality. > I have said hooking an antenna tuner to an > un-balanced (coax)line is a joke, And you were proven otherwise. Many times. > and thru out this entire thread, I have not changed > my opinion. Why not? Why are your beliefs are so tightly held that they can NEVER be challenged through reason? > Boy , where would we be today, if no one ever > challenged previous theories and accepted things > for the way they were. We'd still be in the dark > ages! > Thank GOD for all those who dared to challenge and > make improvements, and new developements, or we would > be 100 years behind. Thank you. I could not have made my point better myself. > I quoted the important parts of the defination from > WIKI, and I never claimed them to be mine. Denying reality, again, Al? The posting in question clearly ended as follows: 73 de W4LGH - Alan http://www.w4lgh.com This is how we properly cite quotes and references: "The fact that an opinion has been widely held is no evidence that it is not utterly absurd; indeed, in view of the silliness of the majority of mankind, a widespread belief is more often likely to be foolish than sensible." -- Betrand Russell, in "Marriage and Morals", 1929 And since you like Wikipedia: http://en.wikipedia.org/wiki/Plagiarism > Good nite Stan! I can't wait to hear what you have > to say, or copy next! You have for sure proven you > are the EXPERT with COPY/PASTE functions, hands down! That one's just too easy... 73, de John, KD2BD
Reply to a comment by : KD2BD on 2007-02-28

W4LGH wrote: >> John, KD2BD wrote..."It's not an issue of belief. >> It's not an issue of blind faith. What we're >> discussing isn't black magic, voodoo, or religion. >> Its Science." > > Here we go with this perfect world again. They are > THEORIES in Science/Physics! Does your transmitter operate through proven theories of math and science, or through an arbitrary belief system? > In physics, the term theory is generally used for > a "mathematical framework" - derived from a small > set of basic principles... Thanks for the explanation. However, you lifted it directly from Wikipedia without citing it as a source. Sad. Very sad... 73, de John, KD2BD
Reply to a comment by : W4LGH on 2007-02-28

John, KD2BD wrote..."It's not an issue of belief. It's not an issue of blind faith. What we're discussing isn't black magic, voodoo, or religion. Its Science." Here we go with this perfect world again. They are THEORIES in Science/Physics! In physics, the term theory is generally used for a "mathematical framework", derived from a small set of basic principles (usually symmetries - like equality of locations in space or in time, or identity of electrons, etc), which is capable of producing experimental "predictions" for a given category of physical systems. A good example is electromagnetic theory, which encompasses the results that can be derived from gauge symmetry (sometimes called gauge invariance) in a form of a few equations called Maxwell's equations. Another name for this theory is classical electromagnetism. Note that the specific theoretical aspects of classical electromagnetic theory, which have been consistently and successfully replicated for well over a century, are termed "laws of electromagnetism", reflecting the fact that they are today "taken as granted". Within electromagnetic theory generally, there are numerous hypotheses about how electromagnetism applies to "specific situations". Many of these hypotheses are already considered to be adequately tested, with "new ones always in the making", and perhaps untested as yet. So do what you want, take what has been said for the past 100 years for granted, or understand that the math does not fit every "specific situation" or go back to your perfect world, and totally believe that the "LAWS of ELECTROMAGNETISM" are and will always be the same for every application, without any chance of improvement. Boy , where would we be today, if no one ever challenged previous theories and accepted things for the way they were. We'd still be in the dark ages! Certainly wouldn't be any Ham radio, tv, internet... Thank GOD for all those who dared to challenge and make improvements, and new developements, or we would be 100 years behind. If you always do what you have always done, you will always get what you have always gotten. Now there's a fact for you! This is getting old now, for there is a serious lack of imagination for without which, there can be no future! 73 de W4LGH - Alan http://www.w4lgh.com
Reply to a comment by : KD2BD on 2007-02-28

W4EF wrote: > W4LGH wrote: >> >> walk alone it and watch it light! Coax is shielded >> and technically does NOT radiate, you can have >> common mode currents ride the shield back into the >> shack, especially if your antenna is not resonant, >> but this energy is rarely if ever radiated, >> therefore it can NOT be tuned into the antenna >> system. > > Alan, this just simply isn't true. By definition, > common-mode current flows on the outside of the coax > shield. It always causes radiation. And besides, > common-mode current is a red herring with regard to > this debate. Antenna feedpoint mismatch doesn't > automatically imply common mode feedline current. > You can have very high VSWR on both coax and > open-wire lines without having feeder current > imbalance (i.e. common-mode current). > > Your comments are so off base on all of this stuff, > I simply don't know where to begin. Agreed. Current flow on the outside of the coax's shield is NOT the result of an impedance mismatch at the feed point, or the antenna being off resonance. It is the result of feeding a balanced antenna with an unbalanced transmission line. When we feed a perfectly balanced dipole (and it doesn't even have to be resonant), and wish to maintain its balance, we feed each half with equal and opposite voltages and currents. (Differential feed.) If we could feed just one side of the dipole (with respect to ground) and see what happens in slow motion, we would see that as the RF voltage begins to rise in a positive direction on the left side of the dipole, an equal and opposite voltage will start to develop on the right. This is not unlike the way a child's seesaw operates. If we push down on one end, the other end moves up by an equal amount. We cannot push down or lift both ends at the same time with the same amount of force and expect the seesaw to move. A transmitter places the shield of its coaxial feed at the same potential as its chassis, close to what IT considers to be an RF ground. This potential is maintained all the way to the end of the feed line, IF it is terminated in an unbalanced load, regardless of the impedance. What happens when we feed a dipole with coax? Remember that neither side of the dipole's feed point is at RF ground potential. If, at one instant of time, we apply +70 volts through the inner conductor to the right side of the dipole, left side will respond by developing -70 volts. Connecting the coax shield directly to either side of the dipole places an RF voltage on the shield where none should exist. This improper feed arrangement causes imbalance in the antenna, radiation and current flow along the outside of the shield of the line, and could lead to "RF feedback" and "RF burn" situations in the shack. The good news is that a balun at the feed point will help alleviate the problem. However, unless the coax is brought down exactly perpendicular with respect to the dipole, it will tend to interact (slightly couple to) one side of the dipole more than the other, resulting in a slight imbalance of the antenna, and some RF current flow along the outside of the coax's shield below the point of the balun due to this coupling. What if we were to feed the dipole with balanced line? First of all, is the dipole perfectly balanced? (Are both halves under the EXACT same influence of the ground and other surrounding objects?) Probably not. Is the feedline run exactly perpendicular to the antenna (as was needed in the case with coax) and kept far away from influencing objects? If either one of these conditions are not fully met, then the antenna SYSTEM is not perfectly balanced, even though your balanced tuner is mistakingly assuming it is! I think the issues that affect balanced lines can be minimized somewhat by simply twisting the line, maybe one turn every couple of feet. This will tend to give each leg a fairly equal opportunity to couple into one side of the dipole or the other, minimizing any "bias" toward any one side. W4LGH wrote: > You guys do whatever you want to do, believe whatever > you want to believe. It's not an issue of belief. It's not an issue of blind faith. What we're discussing isn't black magic, voodoo, or religion. It's science. You can BELIEVE that open wire line "becomes part of the antenna" while coax does not, and that a variable impedance matching device connected to a coaxial transmission line does nothing more than "fool the transmitter"... But that simply does not make it a REALITY. 73, de John, KD2BD
Reply to a comment by : W4EF on 2007-02-27

W4LGH wrote: >> walk alone it and watch it light! Coax is shielded and technically does NOT radiate, you can have common mode currents ride the shield back into the shack, especially if your antenna is not resonant, but this energy is rarely if ever radiated, therefore it can NOT be tuned into the antenna system. << Alan, this just simply isn't true. By definition, common-mode current flows on the outside of the coax shield. It always causes radiation. And besides, common-mode current is a red herring with regard to this debate. Antenna feedpoint mismatch doesn't automatically imply common mode feedline current. You can have very high VSWR on both coax and open-wire lines without having feeder current imbalance (i.e. common-mode current). Your comments are so off base on all of this stuff, I simply don't know where to begin. Because, I am working 12 to 14 hour days on my day job, I just don't have time to thoroughly respond to all of the wrong-headed ideas you are presenting here, so I suggest you do the following "real world experiment": Since you hold Walt Maxwell in such high esteem (as do I), send him a synopsys of all your claims in this thread. I'd bet the ranch that he will take exception to much of what you are claiming, especially your notions of common-mode current and antenna resonance. Thanks for the spirited debate. Gotta go (work is calling). 73, Mike W4EF.........................
Reply to a comment by : W4LGH on 2007-02-27

KD2BD writes... "But, remember: This isn't about loss. :-) It's about a claim that a variable impedance matching device at the transmitter operates in a different manner depending on whether the antenna system is coax or open-wire fed, and that open-wire feed "becomes part of the antenna", whereas coax does not. Why the double-standard?" There is no double standard, it is 2 complely different feed systems. Open or balanced line has comsiderable less loss, its non-shielded so it can and does radiate. Simple proof test there too. Take a floursent bulb out and hold it next to the feed line , walk alone it and watch it light! Coax is shielded and technically does NOT radiate, you can have common mode currents ride the shield back into the shack, especially if your antenna is not resonant, but this energy is rarely if ever radiated, therefore it can NOT be tuned into the antenna system. The balanced feed line can and does radiate, so it can be effectively tuned into the antenna system. So there is no dual standard, its 2 completely different ways of getting your RF to the antenna. One works ok with acceptable trade off's, and the other one doesn't. 73 de W4LGH - Alan http://www.w4lgh.com And I am really done this time. This is getting way to old now.
Reply to a comment by : W4LGH on 2007-02-27

K9IUQ wrote~"Finally something we can agree on."~ Now thats damn scary! There is nothing magical about any antenna. If what you have works for you ,then so be it! All antennas are trade off's, even the resonant dipole, you trade off use on other bands. I have the luxury of having resonant dipoles for the major bands I work, my benchmarks so me more power being radiated, and higher receive signals. The losses were to great using a tuner inside for me.
Reply to a comment by : K9IUQ on 2007-02-27

W4LGH says: f you put something up, and it seems to work great, and you can talk to everyone you hear, this is NOT a BENCHMARK...as you don't know who you are NOT hearing. .................................................... Finally something we can agree on. When testing antennas you should always test a new antenna against a known well performing antenna. As one who has put up (and taken down) over a hundred different antennas in his lifetime, the well used term "I can work them if I can hear em " is NOT a benchmark. I have tested your valued resonant coax fed dipole against MANY other antennas in my lifetime. Contrary to what you believe I am not an idiot. Having tested and used over a hundred different antennas, resonant, non resonant and even your valued trap dipole, I can assure you the resonant coax dipole has NO magical properties over many other antennas with or without a tuner. If a resonant coax dipole was magical, better than other antennas, I would be using one. Alas it is not so, hence my present antenna farm looks much like Walter Maxwell's. Not because Walter said so BUT I did my own bencharks thru many years and proved to myself what works best. K9IUQ
WB5PLJ2007-02-28
RE: Benchmarks
<W4LGH quote>
And I still say using a tuner in your shack hooked to un-balanced line (coax) is ABSURD! You are only fooling yourself and your radio. You are NOT making your antenna work any better! Put the tuner/matching network @ the antenna, then you are doing something. Feed a dippole with open lead (balanced line) into your shack to a tuner, then you are tuning the feed line into the antenna, and that works somewhat.

Install a resonant antenna system fed with low loss coax and now you really have something nice, and its done the right way. I have said that from the begining, and I stand by what I say. I have not changed my opinion, nor have I put any spin on words.

I still say if Stan truely believes that the manufactures build in antenna tuners into the new rigs, and that how he justifies that antenna tuners hooked to un-balanced line are good and work, I still
say you sir are an IDIOT, and I still think you should buy the ocean front properity in Azronia, while its still a bargin! Stan you can spin it anyway you want, say whatever you want, its a free country. I know what I have said, and I know what everyone else on here has said, including you sir. I am done with this silly ass you said, he said, they said, BS.
I will send you some cheese to go with your wine, but you can have it all to yourself. Say you won if you want, call it whatever, but I am not longer going to play your silly game.


My junk works, I have no tuners on ANY lines, my antenna systems are resonant. You do what you want!

73 de W4LGH - ALan
http://www.w4lgh.com


</quote>

Wow I am always amazed by the human race. Just about the time you have seen the most absurd things the most times, another cow comes along and shows you the same cow pie! You my friend should have your licence revoked! just on grounds of no ability to learn or rationalize. Come to think of that you should have your Drivers licence revoked as well, and your diploma if you have one. Just to be on the safe side. neuter him before he breads! support natural selection!

Now to explain (no to much to explain, I will sum up) again what so many others on this thread have said already. you can not have a perfectly resonate system in the real world no matter how hard you try. So what is it you are going on about? If you are transmitting voice you will be operating in a bandwidth based on the amplitude of the signal (or frequency response if it is FM as opposed to AM/SSB). If you are transmitting CW you will have a bandwidth based on the amplitude of your signal. Until you have a completely isolated environment to construct your antenna system in, and the ability to cut your antenna to extremely finite lengths (maybe if you developer some kind of nanite technology to actually build the antenna for you, you could achieve this level of accuracy) you can develop a completely resonant system. Of course if you have a completely isolated environment in which to construct this fanciful antenna system you will have removed all of the elements that RF Radiation uses as a medium to travel through! Congratulations you have just made the first Isotropic radiator, But one of the little things they don't tell you about Isotropic radiators is they don't Radiate! Their is no environment for the radiator to radiate into! Sure their is nothing in the environment that will adversely affect the radiator but! their is nothing in the environment conducive to the Radiator!!!!!! thus making your perfect antenna system completely redundant and useless. much like your apparently superfluous bran.

On the other hand you could devote your entire life to trying to work out the calculations needed to account for the field effects on your (perfect nanite built) antenna system as it runs in the real world and then have your little nanite army modify your antenna to account for the environment. Of course you realize that would mean you would have to be able to predict (amongst other things) the weather perfectly as the state of the atmosphere has a direct affect on resonance of your antenna and oh my god we couldn't possibly run an antenna that is not perfectly resonate!

Now I will leave it up to your staggering intellect to work out how to modulate any transmissions without out taking up more than an infinitesimally small amount of bandwidth!

By the Way Alan, you do not have a resonate antenna system! you have a kind of resonate system, or a somewhat resonate system! A perfectly resonate antenna system that you can use with any ham radio form of modulation can not function in a resonate way. This is fundamentally impossible!

And by the way sir! you started calling people names without having your facts strait so for once I am snapping back at you and just pointing out how much of an idiot you are. Please for the love of god STOP BREATHING MY AIR!!!!!!!


Reply to a comment by : W4LGH on 2007-02-25

And I still say using a tuner in your shack hooked to un-balanced line (coax) is ABSURD! You are only fooling yourself and your radio. You are NOT making your antenna work any better! Put the tuner/matching network @ the antenna, then you are doing something. Feed a dippole with open lead (balanced line) into your shack to a tuner, then you are tuning the feed line into the antenna, and that works somewhat. Install a resonant antenna system fed with low loss coax and now you really have something nice, and its done the right way. I have said that from the begining, and I stand by what I say. I have not changed my opinion, nor have I put any spin on words. I still say if Stan truely believes that the manufactures build in antenna tuners into the new rigs, and that how he justifies that antenna tuners hooked to un-balanced line are good and work, I still say you sir are an IDIOT, and I still think you should buy the ocean front properity in Azronia, while its still a bargin! Stan you can spin it anyway you want, say whatever you want, its a free country. I know what I have said, and I know what everyone else on here has said, including you sir. I am done with this silly ass you said, he said, they said, BS. I will send you some cheese to go with your wine, but you can have it all to yourself. Say you won if you want, call it whatever, but I am not longer going to play your silly game. My junk works, I have no tuners on ANY lines, my antenna systems are resonant. You do what you want! 73 de W4LGH - ALan http://www.w4lgh.com
Reply to a comment by : KC8QFP on 2007-02-25

IMO, Tuners are something that I'd rather do without. I'd like to do away with all the damn wire and the infamous matchbox for good! I don't understand why hams seem to like the darn things, maybe its the two big knobs to play with or something? I was thinking about setting up a shack like in a treehouse so I would not need the coax and matchbox. Then I could connect the antenna directly to my rig. Just call me Tarzan! Hi Hi! I don't know if it is Murphy's Law or what, but wire seems to always get all tangled up in a mess. It's worse than a garden hose! Just drop a wire on the floor, and it's a tangled mess of knots! All the wires on my confuser, my hifi system, TV/VCR, ham radio junk, PA system (for music), and the XMAS lights (don't forget the XMAS lights)! If it were to be a choice between a matched antenna or a matchbox, I go with the proper antenna hands down! As for benchmark numbers and specs vs actual performance, that is sort of like when you put up your antenna, avoid perfect weather, it doesn't work right, you have to put your antenna up when the weather is bad for it to work right! Cheerz! Don
Reply to a comment by : K9IUQ on 2007-02-25

W4GLH continues with his ranting: You made the statemant if tuners weren't any good, why did they put them in radios? K9IUQ says without vulgarity: Don't try to spin what I say, like you do with your comments. You want to quote what I say in past posts, fine. Since you don't seem to know how to use the find key in a Browser, here is what was said word for word NO SPIN and DIRECT QUOTES: .................. You W4LGH said: The idea of an antenna tuner hooked to an un-balanced line (coax) is absurd And K9IUQ replied : If this was true we wouldn't have built-in antenna tuners in our rigs. Stan K9IUQ
Reply to a comment by : W4LGH on 2007-02-25

Stan K9IUQ wrote.. But remember W4LGH said The idea of an antenna tuner hooked to an un-balanced line (coax) is absurd. And w4LGH said the reason they put antenna tuners in radios is so F#$KING IDIOTS like you will BUY THEM!! Statements like that I have a REAL problem with. ================ Why is that Stan, did you just learn you are a F#^KING IDIOT? Would you like some cheese to go with that wine? W4LGH said this and W4LGH said that... Jesus H Crist Stan...GROW UP! You made the statemant if tuners weren't any good, why did they put them in radios? If that statement is the basis of your logic, I rest my case! Damn I hate it when someone pushes me into calling them names, but I guess if the shoe fits...
Reply to a comment by : KC8QFP on 2007-02-25

There was a discussion on the ""Where will Ham Radio be 50 Years from Now"" about remote control wireless link between the shack and tower, i.e. no more need for feedline! You'd have a control head or PC remote that might use IR, low powered RF, or LASER to send signals to the tower for xceiver remote control, rotor, and perhaps even linear. So the tower would onlyneed a power source (120/220VAC 10g line). They do this with X-10 cameras, I was thinking about mounting one of those up on my tower. A simple way to direct couple the transmitter to the antenna! WOW! I sure would like to see TenTec or Drake make such a rig! YaeComWood already has full spectrum HT's, and TenTec has a PC controlled xceiver, with a few mods, this would be a great RC rig (if it has a USB port). I sure would like to see Drake get back into ham radio with such a rig! 73, Don
Reply to a comment by : K9IUQ on 2007-02-25

N3OX says It's also a *fact* that feeding a 20m dipole on 40m (14-j1000) through 30 feet of RG-8/X coax leads to 16dB feedline loss. Both of these cases (good coax, 5:1 SWR and common, cheap coax, 670:1 SWR) are encountered in amateur radio every day. The first one by people who are sensibly trying to stretch the frequency coverage of their 75m/80m dipole without complicated tricks at the antenna, and the latter by people who find that they can "find a match" on 40m with their 20m dipole and they can hear stations. In the former case, it's fine to use the tuner on your coax fed antenna. In the latter, it's absurd. ......................................................... I agree with you 100 percent, there is a time and place for an antenna tuner on coax. But remember W4LGH said The idea of an antenna tuner hooked to an un-balanced line (coax) is absurd. And w4LGH said the reason they put antenna tuners in radios is so F#$KING IDIOTS like you will BUY THEM!! Statements like that I have a REAL problem with. Stan K9IUQ
N4SL2007-02-28
RE: Benchmarks
I Like Cake.
Reply to a comment by : ONAIR on 2007-02-22

Interesting point. So a resonant vertical dipole would then be a lot more efficient than a vertical that you would need to tune?
KD2BD2007-02-28
RE: Benchmarks
W4LGH wrote:
>
> I have said that a resonant antenna was a better
> antenna,

The only non-resonant antennas you are likely to find in wide Amateur Radio use are the Beverage and the Rhombic. These are part of a family of radiators known as Traveling Wave Antennas.

Standing Wave antennas, on the other hand, are resonant, including operating on 17 meters with a 75 meter coax fed dipole through a tuner.

Adjusting the antenna tuner in the shack for a 50 ohm resistive output impedance in this case MAKES THE 75-METER ANTENNA SYSTEM RESONANT ON 17 METERS!

That's not "just a theory". It's reality.

> I have said hooking an antenna tuner to an
> un-balanced (coax)line is a joke,

And you were proven otherwise. Many times.

> and thru out this entire thread, I have not changed
> my opinion.

Why not? Why are your beliefs are so tightly held that they can NEVER be challenged through reason?

> Boy , where would we be today, if no one ever
> challenged previous theories and accepted things
> for the way they were. We'd still be in the dark
> ages!

> Thank GOD for all those who dared to challenge and
> make improvements, and new developements, or we would
> be 100 years behind.

Thank you. I could not have made my point better myself.

> I quoted the important parts of the defination from
> WIKI, and I never claimed them to be mine.

Denying reality, again, Al? The posting in question clearly ended as follows:

73 de W4LGH - Alan
http://www.w4lgh.com

This is how we properly cite quotes and references:

"The fact that an opinion has been widely held is no evidence that it is not utterly absurd; indeed, in view of the silliness of the majority of mankind, a widespread belief is more often likely to be foolish than sensible."

-- Betrand Russell, in "Marriage and Morals", 1929

And since you like Wikipedia:

http://en.wikipedia.org/wiki/Plagiarism

> Good nite Stan! I can't wait to hear what you have
> to say, or copy next! You have for sure proven you
> are the EXPERT with COPY/PASTE functions, hands down!

That one's just too easy...


73, de John, KD2BD
Reply to a comment by : KD2BD on 2007-02-28

W4LGH wrote: >> John, KD2BD wrote..."It's not an issue of belief. >> It's not an issue of blind faith. What we're >> discussing isn't black magic, voodoo, or religion. >> Its Science." > > Here we go with this perfect world again. They are > THEORIES in Science/Physics! Does your transmitter operate through proven theories of math and science, or through an arbitrary belief system? > In physics, the term theory is generally used for > a "mathematical framework" - derived from a small > set of basic principles... Thanks for the explanation. However, you lifted it directly from Wikipedia without citing it as a source. Sad. Very sad... 73, de John, KD2BD
Reply to a comment by : W4LGH on 2007-02-28

John, KD2BD wrote..."It's not an issue of belief. It's not an issue of blind faith. What we're discussing isn't black magic, voodoo, or religion. Its Science." Here we go with this perfect world again. They are THEORIES in Science/Physics! In physics, the term theory is generally used for a "mathematical framework", derived from a small set of basic principles (usually symmetries - like equality of locations in space or in time, or identity of electrons, etc), which is capable of producing experimental "predictions" for a given category of physical systems. A good example is electromagnetic theory, which encompasses the results that can be derived from gauge symmetry (sometimes called gauge invariance) in a form of a few equations called Maxwell's equations. Another name for this theory is classical electromagnetism. Note that the specific theoretical aspects of classical electromagnetic theory, which have been consistently and successfully replicated for well over a century, are termed "laws of electromagnetism", reflecting the fact that they are today "taken as granted". Within electromagnetic theory generally, there are numerous hypotheses about how electromagnetism applies to "specific situations". Many of these hypotheses are already considered to be adequately tested, with "new ones always in the making", and perhaps untested as yet. So do what you want, take what has been said for the past 100 years for granted, or understand that the math does not fit every "specific situation" or go back to your perfect world, and totally believe that the "LAWS of ELECTROMAGNETISM" are and will always be the same for every application, without any chance of improvement. Boy , where would we be today, if no one ever challenged previous theories and accepted things for the way they were. We'd still be in the dark ages! Certainly wouldn't be any Ham radio, tv, internet... Thank GOD for all those who dared to challenge and make improvements, and new developements, or we would be 100 years behind. If you always do what you have always done, you will always get what you have always gotten. Now there's a fact for you! This is getting old now, for there is a serious lack of imagination for without which, there can be no future! 73 de W4LGH - Alan http://www.w4lgh.com
Reply to a comment by : KD2BD on 2007-02-28

W4EF wrote: > W4LGH wrote: >> >> walk alone it and watch it light! Coax is shielded >> and technically does NOT radiate, you can have >> common mode currents ride the shield back into the >> shack, especially if your antenna is not resonant, >> but this energy is rarely if ever radiated, >> therefore it can NOT be tuned into the antenna >> system. > > Alan, this just simply isn't true. By definition, > common-mode current flows on the outside of the coax > shield. It always causes radiation. And besides, > common-mode current is a red herring with regard to > this debate. Antenna feedpoint mismatch doesn't > automatically imply common mode feedline current. > You can have very high VSWR on both coax and > open-wire lines without having feeder current > imbalance (i.e. common-mode current). > > Your comments are so off base on all of this stuff, > I simply don't know where to begin. Agreed. Current flow on the outside of the coax's shield is NOT the result of an impedance mismatch at the feed point, or the antenna being off resonance. It is the result of feeding a balanced antenna with an unbalanced transmission line. When we feed a perfectly balanced dipole (and it doesn't even have to be resonant), and wish to maintain its balance, we feed each half with equal and opposite voltages and currents. (Differential feed.) If we could feed just one side of the dipole (with respect to ground) and see what happens in slow motion, we would see that as the RF voltage begins to rise in a positive direction on the left side of the dipole, an equal and opposite voltage will start to develop on the right. This is not unlike the way a child's seesaw operates. If we push down on one end, the other end moves up by an equal amount. We cannot push down or lift both ends at the same time with the same amount of force and expect the seesaw to move. A transmitter places the shield of its coaxial feed at the same potential as its chassis, close to what IT considers to be an RF ground. This potential is maintained all the way to the end of the feed line, IF it is terminated in an unbalanced load, regardless of the impedance. What happens when we feed a dipole with coax? Remember that neither side of the dipole's feed point is at RF ground potential. If, at one instant of time, we apply +70 volts through the inner conductor to the right side of the dipole, left side will respond by developing -70 volts. Connecting the coax shield directly to either side of the dipole places an RF voltage on the shield where none should exist. This improper feed arrangement causes imbalance in the antenna, radiation and current flow along the outside of the shield of the line, and could lead to "RF feedback" and "RF burn" situations in the shack. The good news is that a balun at the feed point will help alleviate the problem. However, unless the coax is brought down exactly perpendicular with respect to the dipole, it will tend to interact (slightly couple to) one side of the dipole more than the other, resulting in a slight imbalance of the antenna, and some RF current flow along the outside of the coax's shield below the point of the balun due to this coupling. What if we were to feed the dipole with balanced line? First of all, is the dipole perfectly balanced? (Are both halves under the EXACT same influence of the ground and other surrounding objects?) Probably not. Is the feedline run exactly perpendicular to the antenna (as was needed in the case with coax) and kept far away from influencing objects? If either one of these conditions are not fully met, then the antenna SYSTEM is not perfectly balanced, even though your balanced tuner is mistakingly assuming it is! I think the issues that affect balanced lines can be minimized somewhat by simply twisting the line, maybe one turn every couple of feet. This will tend to give each leg a fairly equal opportunity to couple into one side of the dipole or the other, minimizing any "bias" toward any one side. W4LGH wrote: > You guys do whatever you want to do, believe whatever > you want to believe. It's not an issue of belief. It's not an issue of blind faith. What we're discussing isn't black magic, voodoo, or religion. It's science. You can BELIEVE that open wire line "becomes part of the antenna" while coax does not, and that a variable impedance matching device connected to a coaxial transmission line does nothing more than "fool the transmitter"... But that simply does not make it a REALITY. 73, de John, KD2BD
Reply to a comment by : W4EF on 2007-02-27

W4LGH wrote: >> walk alone it and watch it light! Coax is shielded and technically does NOT radiate, you can have common mode currents ride the shield back into the shack, especially if your antenna is not resonant, but this energy is rarely if ever radiated, therefore it can NOT be tuned into the antenna system. << Alan, this just simply isn't true. By definition, common-mode current flows on the outside of the coax shield. It always causes radiation. And besides, common-mode current is a red herring with regard to this debate. Antenna feedpoint mismatch doesn't automatically imply common mode feedline current. You can have very high VSWR on both coax and open-wire lines without having feeder current imbalance (i.e. common-mode current). Your comments are so off base on all of this stuff, I simply don't know where to begin. Because, I am working 12 to 14 hour days on my day job, I just don't have time to thoroughly respond to all of the wrong-headed ideas you are presenting here, so I suggest you do the following "real world experiment": Since you hold Walt Maxwell in such high esteem (as do I), send him a synopsys of all your claims in this thread. I'd bet the ranch that he will take exception to much of what you are claiming, especially your notions of common-mode current and antenna resonance. Thanks for the spirited debate. Gotta go (work is calling). 73, Mike W4EF.........................
Reply to a comment by : W4LGH on 2007-02-27

KD2BD writes... "But, remember: This isn't about loss. :-) It's about a claim that a variable impedance matching device at the transmitter operates in a different manner depending on whether the antenna system is coax or open-wire fed, and that open-wire feed "becomes part of the antenna", whereas coax does not. Why the double-standard?" There is no double standard, it is 2 complely different feed systems. Open or balanced line has comsiderable less loss, its non-shielded so it can and does radiate. Simple proof test there too. Take a floursent bulb out and hold it next to the feed line , walk alone it and watch it light! Coax is shielded and technically does NOT radiate, you can have common mode currents ride the shield back into the shack, especially if your antenna is not resonant, but this energy is rarely if ever radiated, therefore it can NOT be tuned into the antenna system. The balanced feed line can and does radiate, so it can be effectively tuned into the antenna system. So there is no dual standard, its 2 completely different ways of getting your RF to the antenna. One works ok with acceptable trade off's, and the other one doesn't. 73 de W4LGH - Alan http://www.w4lgh.com And I am really done this time. This is getting way to old now.
Reply to a comment by : W4LGH on 2007-02-27

K9IUQ wrote~"Finally something we can agree on."~ Now thats damn scary! There is nothing magical about any antenna. If what you have works for you ,then so be it! All antennas are trade off's, even the resonant dipole, you trade off use on other bands. I have the luxury of having resonant dipoles for the major bands I work, my benchmarks so me more power being radiated, and higher receive signals. The losses were to great using a tuner inside for me.
Reply to a comment by : K9IUQ on 2007-02-27

W4LGH says: f you put something up, and it seems to work great, and you can talk to everyone you hear, this is NOT a BENCHMARK...as you don't know who you are NOT hearing. .................................................... Finally something we can agree on. When testing antennas you should always test a new antenna against a known well performing antenna. As one who has put up (and taken down) over a hundred different antennas in his lifetime, the well used term "I can work them if I can hear em " is NOT a benchmark. I have tested your valued resonant coax fed dipole against MANY other antennas in my lifetime. Contrary to what you believe I am not an idiot. Having tested and used over a hundred different antennas, resonant, non resonant and even your valued trap dipole, I can assure you the resonant coax dipole has NO magical properties over many other antennas with or without a tuner. If a resonant coax dipole was magical, better than other antennas, I would be using one. Alas it is not so, hence my present antenna farm looks much like Walter Maxwell's. Not because Walter said so BUT I did my own bencharks thru many years and proved to myself what works best. K9IUQ
K6IOU2007-02-28
RE: Benchmarks
Sorry all . . . the link above no longer appears to be valid. I should have tested it before posting.

DON
K6IOU
Reply to a comment by : K6IOU on 2007-02-28

To all: The link below provides some interesting reading concerning the things that have been discussed above. The author relates complicated concepts in an easy to understand and sometimes humorous way. He clears-up, at least to my way of thinking, many of the old wives tales that have been bandied about here lately. http://members.dslextreme.com/users/w6wqc/antenna.html DON K6IOU
Reply to a comment by : K9IUQ on 2007-02-28

K6IOU says With all due respect Al [W4LGH], You are disputing some of the most basic concepts of antenna design and operation, concepts that have been proven time and time again. How can this be? ........................................................ This a MOST interesting question, one I have been trying to figure out for 47 years. The Antenna Truths are there for us all to read. So why do Hams like W4LGH continue to spew myths and untruths? Certainly Al is not dumb, he says is a "BroadCast Engineer", he must have *some* education in antenna theory. So why does he believe the way he does? Contrary to what has been proven time and again in the antenna literature. Is it because he *thinks* he is smarter than all the antenna books? Is his ego so strong he just has to be right, never admitting he could be wrong. I have heard countless discussions on the air that spew the same myths and untruths that we have heard Al say. WHY???? There must be an answer somewhere. Stan K9IUQ
Reply to a comment by : K6IOU on 2007-02-28

Hi again Al [W4LGH], On a positive note . . . you did a very nice job with your website. Great pics, organization. Certainly a station to be proud of. I also agree with you on your choice of audio: I also use a Behringer mixer and studio mic [Oktava MC 012]. DON K6IOU
Reply to a comment by : K6IOU on 2007-02-28

With all due respect Al [W4LGH], the issues being discussed here and contradictory to some of your statements are well covered in the ARRL Antenna Handbook . . . a reference book that all hams should have, study, and attempt to understand. I think it is fair to say that the Handbook is a culmination of a hundred years or so of math, research and antenna experimentation. The issues discussed have been studied and tested in the real world by a wide variety of experts in the field. It includes both the theoretical and 'real world' data. You are disputing some of the most basic concepts of antenna design and operation, concepts that have been proven time and time again. How can this be? Perhaps we [antenna experimenters] would be even further ahead if mis-information such as yours was not continually espoused as truth. DON K6IOU
Reply to a comment by : KD2BD on 2007-02-28

W4LGH wrote: >> John, KD2BD wrote..."It's not an issue of belief. >> It's not an issue of blind faith. What we're >> discussing isn't black magic, voodoo, or religion. >> Its Science." > > Here we go with this perfect world again. They are > THEORIES in Science/Physics! Does your transmitter operate through proven theories of math and science, or through an arbitrary belief system? > In physics, the term theory is generally used for > a "mathematical framework" - derived from a small > set of basic principles... Thanks for the explanation. However, you lifted it directly from Wikipedia without citing it as a source. Sad. Very sad... 73, de John, KD2BD
Reply to a comment by : W4LGH on 2007-02-28

John, KD2BD wrote..."It's not an issue of belief. It's not an issue of blind faith. What we're discussing isn't black magic, voodoo, or religion. Its Science." Here we go with this perfect world again. They are THEORIES in Science/Physics! In physics, the term theory is generally used for a "mathematical framework", derived from a small set of basic principles (usually symmetries - like equality of locations in space or in time, or identity of electrons, etc), which is capable of producing experimental "predictions" for a given category of physical systems. A good example is electromagnetic theory, which encompasses the results that can be derived from gauge symmetry (sometimes called gauge invariance) in a form of a few equations called Maxwell's equations. Another name for this theory is classical electromagnetism. Note that the specific theoretical aspects of classical electromagnetic theory, which have been consistently and successfully replicated for well over a century, are termed "laws of electromagnetism", reflecting the fact that they are today "taken as granted". Within electromagnetic theory generally, there are numerous hypotheses about how electromagnetism applies to "specific situations". Many of these hypotheses are already considered to be adequately tested, with "new ones always in the making", and perhaps untested as yet. So do what you want, take what has been said for the past 100 years for granted, or understand that the math does not fit every "specific situation" or go back to your perfect world, and totally believe that the "LAWS of ELECTROMAGNETISM" are and will always be the same for every application, without any chance of improvement. Boy , where would we be today, if no one ever challenged previous theories and accepted things for the way they were. We'd still be in the dark ages! Certainly wouldn't be any Ham radio, tv, internet... Thank GOD for all those who dared to challenge and make improvements, and new developements, or we would be 100 years behind. If you always do what you have always done, you will always get what you have always gotten. Now there's a fact for you! This is getting old now, for there is a serious lack of imagination for without which, there can be no future! 73 de W4LGH - Alan http://www.w4lgh.com
Reply to a comment by : KD2BD on 2007-02-28

W4EF wrote: > W4LGH wrote: >> >> walk alone it and watch it light! Coax is shielded >> and technically does NOT radiate, you can have >> common mode currents ride the shield back into the >> shack, especially if your antenna is not resonant, >> but this energy is rarely if ever radiated, >> therefore it can NOT be tuned into the antenna >> system. > > Alan, this just simply isn't true. By definition, > common-mode current flows on the outside of the coax > shield. It always causes radiation. And besides, > common-mode current is a red herring with regard to > this debate. Antenna feedpoint mismatch doesn't > automatically imply common mode feedline current. > You can have very high VSWR on both coax and > open-wire lines without having feeder current > imbalance (i.e. common-mode current). > > Your comments are so off base on all of this stuff, > I simply don't know where to begin. Agreed. Current flow on the outside of the coax's shield is NOT the result of an impedance mismatch at the feed point, or the antenna being off resonance. It is the result of feeding a balanced antenna with an unbalanced transmission line. When we feed a perfectly balanced dipole (and it doesn't even have to be resonant), and wish to maintain its balance, we feed each half with equal and opposite voltages and currents. (Differential feed.) If we could feed just one side of the dipole (with respect to ground) and see what happens in slow motion, we would see that as the RF voltage begins to rise in a positive direction on the left side of the dipole, an equal and opposite voltage will start to develop on the right. This is not unlike the way a child's seesaw operates. If we push down on one end, the other end moves up by an equal amount. We cannot push down or lift both ends at the same time with the same amount of force and expect the seesaw to move. A transmitter places the shield of its coaxial feed at the same potential as its chassis, close to what IT considers to be an RF ground. This potential is maintained all the way to the end of the feed line, IF it is terminated in an unbalanced load, regardless of the impedance. What happens when we feed a dipole with coax? Remember that neither side of the dipole's feed point is at RF ground potential. If, at one instant of time, we apply +70 volts through the inner conductor to the right side of the dipole, left side will respond by developing -70 volts. Connecting the coax shield directly to either side of the dipole places an RF voltage on the shield where none should exist. This improper feed arrangement causes imbalance in the antenna, radiation and current flow along the outside of the shield of the line, and could lead to "RF feedback" and "RF burn" situations in the shack. The good news is that a balun at the feed point will help alleviate the problem. However, unless the coax is brought down exactly perpendicular with respect to the dipole, it will tend to interact (slightly couple to) one side of the dipole more than the other, resulting in a slight imbalance of the antenna, and some RF current flow along the outside of the coax's shield below the point of the balun due to this coupling. What if we were to feed the dipole with balanced line? First of all, is the dipole perfectly balanced? (Are both halves under the EXACT same influence of the ground and other surrounding objects?) Probably not. Is the feedline run exactly perpendicular to the antenna (as was needed in the case with coax) and kept far away from influencing objects? If either one of these conditions are not fully met, then the antenna SYSTEM is not perfectly balanced, even though your balanced tuner is mistakingly assuming it is! I think the issues that affect balanced lines can be minimized somewhat by simply twisting the line, maybe one turn every couple of feet. This will tend to give each leg a fairly equal opportunity to couple into one side of the dipole or the other, minimizing any "bias" toward any one side. W4LGH wrote: > You guys do whatever you want to do, believe whatever > you want to believe. It's not an issue of belief. It's not an issue of blind faith. What we're discussing isn't black magic, voodoo, or religion. It's science. You can BELIEVE that open wire line "becomes part of the antenna" while coax does not, and that a variable impedance matching device connected to a coaxial transmission line does nothing more than "fool the transmitter"... But that simply does not make it a REALITY. 73, de John, KD2BD
Reply to a comment by : W4EF on 2007-02-27

W4LGH wrote: >> walk alone it and watch it light! Coax is shielded and technically does NOT radiate, you can have common mode currents ride the shield back into the shack, especially if your antenna is not resonant, but this energy is rarely if ever radiated, therefore it can NOT be tuned into the antenna system. << Alan, this just simply isn't true. By definition, common-mode current flows on the outside of the coax shield. It always causes radiation. And besides, common-mode current is a red herring with regard to this debate. Antenna feedpoint mismatch doesn't automatically imply common mode feedline current. You can have very high VSWR on both coax and open-wire lines without having feeder current imbalance (i.e. common-mode current). Your comments are so off base on all of this stuff, I simply don't know where to begin. Because, I am working 12 to 14 hour days on my day job, I just don't have time to thoroughly respond to all of the wrong-headed ideas you are presenting here, so I suggest you do the following "real world experiment": Since you hold Walt Maxwell in such high esteem (as do I), send him a synopsys of all your claims in this thread. I'd bet the ranch that he will take exception to much of what you are claiming, especially your notions of common-mode current and antenna resonance. Thanks for the spirited debate. Gotta go (work is calling). 73, Mike W4EF.........................
Reply to a comment by : W4LGH on 2007-02-27

KD2BD writes... "But, remember: This isn't about loss. :-) It's about a claim that a variable impedance matching device at the transmitter operates in a different manner depending on whether the antenna system is coax or open-wire fed, and that open-wire feed "becomes part of the antenna", whereas coax does not. Why the double-standard?" There is no double standard, it is 2 complely different feed systems. Open or balanced line has comsiderable less loss, its non-shielded so it can and does radiate. Simple proof test there too. Take a floursent bulb out and hold it next to the feed line , walk alone it and watch it light! Coax is shielded and technically does NOT radiate, you can have common mode currents ride the shield back into the shack, especially if your antenna is not resonant, but this energy is rarely if ever radiated, therefore it can NOT be tuned into the antenna system. The balanced feed line can and does radiate, so it can be effectively tuned into the antenna system. So there is no dual standard, its 2 completely different ways of getting your RF to the antenna. One works ok with acceptable trade off's, and the other one doesn't. 73 de W4LGH - Alan http://www.w4lgh.com And I am really done this time. This is getting way to old now.
Reply to a comment by : W4LGH on 2007-02-27

K9IUQ wrote~"Finally something we can agree on."~ Now thats damn scary! There is nothing magical about any antenna. If what you have works for you ,then so be it! All antennas are trade off's, even the resonant dipole, you trade off use on other bands. I have the luxury of having resonant dipoles for the major bands I work, my benchmarks so me more power being radiated, and higher receive signals. The losses were to great using a tuner inside for me.
Reply to a comment by : K9IUQ on 2007-02-27

W4LGH says: f you put something up, and it seems to work great, and you can talk to everyone you hear, this is NOT a BENCHMARK...as you don't know who you are NOT hearing. .................................................... Finally something we can agree on. When testing antennas you should always test a new antenna against a known well performing antenna. As one who has put up (and taken down) over a hundred different antennas in his lifetime, the well used term "I can work them if I can hear em " is NOT a benchmark. I have tested your valued resonant coax fed dipole against MANY other antennas in my lifetime. Contrary to what you believe I am not an idiot. Having tested and used over a hundred different antennas, resonant, non resonant and even your valued trap dipole, I can assure you the resonant coax dipole has NO magical properties over many other antennas with or without a tuner. If a resonant coax dipole was magical, better than other antennas, I would be using one. Alas it is not so, hence my present antenna farm looks much like Walter Maxwell's. Not because Walter said so BUT I did my own bencharks thru many years and proved to myself what works best. K9IUQ
K6IOU2007-02-28
RE: Benchmarks
To all:

The link below provides some interesting reading concerning the things that have been discussed above. The author relates complicated concepts in an easy to understand and sometimes humorous way.

He clears-up, at least to my way of thinking, many of the old wives tales that have been bandied about here lately.

http://members.dslextreme.com/users/w6wqc/antenna.html

DON
K6IOU
Reply to a comment by : K9IUQ on 2007-02-28

K6IOU says With all due respect Al [W4LGH], You are disputing some of the most basic concepts of antenna design and operation, concepts that have been proven time and time again. How can this be? ........................................................ This a MOST interesting question, one I have been trying to figure out for 47 years. The Antenna Truths are there for us all to read. So why do Hams like W4LGH continue to spew myths and untruths? Certainly Al is not dumb, he says is a "BroadCast Engineer", he must have *some* education in antenna theory. So why does he believe the way he does? Contrary to what has been proven time and again in the antenna literature. Is it because he *thinks* he is smarter than all the antenna books? Is his ego so strong he just has to be right, never admitting he could be wrong. I have heard countless discussions on the air that spew the same myths and untruths that we have heard Al say. WHY???? There must be an answer somewhere. Stan K9IUQ
Reply to a comment by : K6IOU on 2007-02-28

Hi again Al [W4LGH], On a positive note . . . you did a very nice job with your website. Great pics, organization. Certainly a station to be proud of. I also agree with you on your choice of audio: I also use a Behringer mixer and studio mic [Oktava MC 012]. DON K6IOU
Reply to a comment by : K6IOU on 2007-02-28

With all due respect Al [W4LGH], the issues being discussed here and contradictory to some of your statements are well covered in the ARRL Antenna Handbook . . . a reference book that all hams should have, study, and attempt to understand. I think it is fair to say that the Handbook is a culmination of a hundred years or so of math, research and antenna experimentation. The issues discussed have been studied and tested in the real world by a wide variety of experts in the field. It includes both the theoretical and 'real world' data. You are disputing some of the most basic concepts of antenna design and operation, concepts that have been proven time and time again. How can this be? Perhaps we [antenna experimenters] would be even further ahead if mis-information such as yours was not continually espoused as truth. DON K6IOU
Reply to a comment by : KD2BD on 2007-02-28

W4LGH wrote: >> John, KD2BD wrote..."It's not an issue of belief. >> It's not an issue of blind faith. What we're >> discussing isn't black magic, voodoo, or religion. >> Its Science." > > Here we go with this perfect world again. They are > THEORIES in Science/Physics! Does your transmitter operate through proven theories of math and science, or through an arbitrary belief system? > In physics, the term theory is generally used for > a "mathematical framework" - derived from a small > set of basic principles... Thanks for the explanation. However, you lifted it directly from Wikipedia without citing it as a source. Sad. Very sad... 73, de John, KD2BD
Reply to a comment by : W4LGH on 2007-02-28

John, KD2BD wrote..."It's not an issue of belief. It's not an issue of blind faith. What we're discussing isn't black magic, voodoo, or religion. Its Science." Here we go with this perfect world again. They are THEORIES in Science/Physics! In physics, the term theory is generally used for a "mathematical framework", derived from a small set of basic principles (usually symmetries - like equality of locations in space or in time, or identity of electrons, etc), which is capable of producing experimental "predictions" for a given category of physical systems. A good example is electromagnetic theory, which encompasses the results that can be derived from gauge symmetry (sometimes called gauge invariance) in a form of a few equations called Maxwell's equations. Another name for this theory is classical electromagnetism. Note that the specific theoretical aspects of classical electromagnetic theory, which have been consistently and successfully replicated for well over a century, are termed "laws of electromagnetism", reflecting the fact that they are today "taken as granted". Within electromagnetic theory generally, there are numerous hypotheses about how electromagnetism applies to "specific situations". Many of these hypotheses are already considered to be adequately tested, with "new ones always in the making", and perhaps untested as yet. So do what you want, take what has been said for the past 100 years for granted, or understand that the math does not fit every "specific situation" or go back to your perfect world, and totally believe that the "LAWS of ELECTROMAGNETISM" are and will always be the same for every application, without any chance of improvement. Boy , where would we be today, if no one ever challenged previous theories and accepted things for the way they were. We'd still be in the dark ages! Certainly wouldn't be any Ham radio, tv, internet... Thank GOD for all those who dared to challenge and make improvements, and new developements, or we would be 100 years behind. If you always do what you have always done, you will always get what you have always gotten. Now there's a fact for you! This is getting old now, for there is a serious lack of imagination for without which, there can be no future! 73 de W4LGH - Alan http://www.w4lgh.com
Reply to a comment by : KD2BD on 2007-02-28

W4EF wrote: > W4LGH wrote: >> >> walk alone it and watch it light! Coax is shielded >> and technically does NOT radiate, you can have >> common mode currents ride the shield back into the >> shack, especially if your antenna is not resonant, >> but this energy is rarely if ever radiated, >> therefore it can NOT be tuned into the antenna >> system. > > Alan, this just simply isn't true. By definition, > common-mode current flows on the outside of the coax > shield. It always causes radiation. And besides, > common-mode current is a red herring with regard to > this debate. Antenna feedpoint mismatch doesn't > automatically imply common mode feedline current. > You can have very high VSWR on both coax and > open-wire lines without having feeder current > imbalance (i.e. common-mode current). > > Your comments are so off base on all of this stuff, > I simply don't know where to begin. Agreed. Current flow on the outside of the coax's shield is NOT the result of an impedance mismatch at the feed point, or the antenna being off resonance. It is the result of feeding a balanced antenna with an unbalanced transmission line. When we feed a perfectly balanced dipole (and it doesn't even have to be resonant), and wish to maintain its balance, we feed each half with equal and opposite voltages and currents. (Differential feed.) If we could feed just one side of the dipole (with respect to ground) and see what happens in slow motion, we would see that as the RF voltage begins to rise in a positive direction on the left side of the dipole, an equal and opposite voltage will start to develop on the right. This is not unlike the way a child's seesaw operates. If we push down on one end, the other end moves up by an equal amount. We cannot push down or lift both ends at the same time with the same amount of force and expect the seesaw to move. A transmitter places the shield of its coaxial feed at the same potential as its chassis, close to what IT considers to be an RF ground. This potential is maintained all the way to the end of the feed line, IF it is terminated in an unbalanced load, regardless of the impedance. What happens when we feed a dipole with coax? Remember that neither side of the dipole's feed point is at RF ground potential. If, at one instant of time, we apply +70 volts through the inner conductor to the right side of the dipole, left side will respond by developing -70 volts. Connecting the coax shield directly to either side of the dipole places an RF voltage on the shield where none should exist. This improper feed arrangement causes imbalance in the antenna, radiation and current flow along the outside of the shield of the line, and could lead to "RF feedback" and "RF burn" situations in the shack. The good news is that a balun at the feed point will help alleviate the problem. However, unless the coax is brought down exactly perpendicular with respect to the dipole, it will tend to interact (slightly couple to) one side of the dipole more than the other, resulting in a slight imbalance of the antenna, and some RF current flow along the outside of the coax's shield below the point of the balun due to this coupling. What if we were to feed the dipole with balanced line? First of all, is the dipole perfectly balanced? (Are both halves under the EXACT same influence of the ground and other surrounding objects?) Probably not. Is the feedline run exactly perpendicular to the antenna (as was needed in the case with coax) and kept far away from influencing objects? If either one of these conditions are not fully met, then the antenna SYSTEM is not perfectly balanced, even though your balanced tuner is mistakingly assuming it is! I think the issues that affect balanced lines can be minimized somewhat by simply twisting the line, maybe one turn every couple of feet. This will tend to give each leg a fairly equal opportunity to couple into one side of the dipole or the other, minimizing any "bias" toward any one side. W4LGH wrote: > You guys do whatever you want to do, believe whatever > you want to believe. It's not an issue of belief. It's not an issue of blind faith. What we're discussing isn't black magic, voodoo, or religion. It's science. You can BELIEVE that open wire line "becomes part of the antenna" while coax does not, and that a variable impedance matching device connected to a coaxial transmission line does nothing more than "fool the transmitter"... But that simply does not make it a REALITY. 73, de John, KD2BD
Reply to a comment by : W4EF on 2007-02-27

W4LGH wrote: >> walk alone it and watch it light! Coax is shielded and technically does NOT radiate, you can have common mode currents ride the shield back into the shack, especially if your antenna is not resonant, but this energy is rarely if ever radiated, therefore it can NOT be tuned into the antenna system. << Alan, this just simply isn't true. By definition, common-mode current flows on the outside of the coax shield. It always causes radiation. And besides, common-mode current is a red herring with regard to this debate. Antenna feedpoint mismatch doesn't automatically imply common mode feedline current. You can have very high VSWR on both coax and open-wire lines without having feeder current imbalance (i.e. common-mode current). Your comments are so off base on all of this stuff, I simply don't know where to begin. Because, I am working 12 to 14 hour days on my day job, I just don't have time to thoroughly respond to all of the wrong-headed ideas you are presenting here, so I suggest you do the following "real world experiment": Since you hold Walt Maxwell in such high esteem (as do I), send him a synopsys of all your claims in this thread. I'd bet the ranch that he will take exception to much of what you are claiming, especially your notions of common-mode current and antenna resonance. Thanks for the spirited debate. Gotta go (work is calling). 73, Mike W4EF.........................
Reply to a comment by : W4LGH on 2007-02-27

KD2BD writes... "But, remember: This isn't about loss. :-) It's about a claim that a variable impedance matching device at the transmitter operates in a different manner depending on whether the antenna system is coax or open-wire fed, and that open-wire feed "becomes part of the antenna", whereas coax does not. Why the double-standard?" There is no double standard, it is 2 complely different feed systems. Open or balanced line has comsiderable less loss, its non-shielded so it can and does radiate. Simple proof test there too. Take a floursent bulb out and hold it next to the feed line , walk alone it and watch it light! Coax is shielded and technically does NOT radiate, you can have common mode currents ride the shield back into the shack, especially if your antenna is not resonant, but this energy is rarely if ever radiated, therefore it can NOT be tuned into the antenna system. The balanced feed line can and does radiate, so it can be effectively tuned into the antenna system. So there is no dual standard, its 2 completely different ways of getting your RF to the antenna. One works ok with acceptable trade off's, and the other one doesn't. 73 de W4LGH - Alan http://www.w4lgh.com And I am really done this time. This is getting way to old now.
Reply to a comment by : W4LGH on 2007-02-27

K9IUQ wrote~"Finally something we can agree on."~ Now thats damn scary! There is nothing magical about any antenna. If what you have works for you ,then so be it! All antennas are trade off's, even the resonant dipole, you trade off use on other bands. I have the luxury of having resonant dipoles for the major bands I work, my benchmarks so me more power being radiated, and higher receive signals. The losses were to great using a tuner inside for me.
Reply to a comment by : K9IUQ on 2007-02-27

W4LGH says: f you put something up, and it seems to work great, and you can talk to everyone you hear, this is NOT a BENCHMARK...as you don't know who you are NOT hearing. .................................................... Finally something we can agree on. When testing antennas you should always test a new antenna against a known well performing antenna. As one who has put up (and taken down) over a hundred different antennas in his lifetime, the well used term "I can work them if I can hear em " is NOT a benchmark. I have tested your valued resonant coax fed dipole against MANY other antennas in my lifetime. Contrary to what you believe I am not an idiot. Having tested and used over a hundred different antennas, resonant, non resonant and even your valued trap dipole, I can assure you the resonant coax dipole has NO magical properties over many other antennas with or without a tuner. If a resonant coax dipole was magical, better than other antennas, I would be using one. Alas it is not so, hence my present antenna farm looks much like Walter Maxwell's. Not because Walter said so BUT I did my own bencharks thru many years and proved to myself what works best. K9IUQ
W4LGH2007-02-28
RE: Benchmarks
You know, you guys are something else. What you say could be turned around and directed to all of you as well. I quoted the important parts of the defination from WIKI, and I never claimed them to be mine. I used something that is considered a standard. I have never disputed any of the facts, I have said that a resonant antenna was a better antenna, I have said hooking an antenna tuner to an un-balanced (coax)line is a joke, and thru out this entire thread, I have not changed my opinion. I have never said any of the other types of antennas didn't work, I questioned at what effeciency in the real world, not the prefect world that just about all textbooks work in. I have tried all the different type of antennas in the handbooks, some worked ok, some didn't work worth a damn. I have always gone back to a resonant antenna, fed with the lowest loss coax I could afford, and hooked directly to my transmitter. It has the least trade offs for me.

I have made a damn nice living in the electronics field and have been in it for 35+ years so I must be doing something right? Electronics has not only been my hobby, as it is for some of you, but has also been my profession, and still is.

What some of you are really saying is you don't care about whatever loss you have. If this wasn't the case, how come hams use Screwdriver antennas with a 48" whip...the matching device is at the antenna, why not use a 48" whip hooked to coax and put your antenna tuner inside your car, next to the radio, its the same difference, but the answer is, you can NOT afford the loss. Its the same with any other mobile HF antenna, the matching is done at the antenna, to decrease the loss! Someone would laugh you out of the county if you used a tuner in your car hooked to a 48" whip. Its the same difference doing it in your shack, but you have a larger capture area, and don't care about the loss!! But the loss is there!

I have tried my best to get you guys to open your eyes and see the forrest for the trees, but you keep coming back saying I don't know what I am talking about, throwing quoted formulas around trying to prove yourself. We certainly would not have advanced in technology if we all sat back and accepted everytime that was ever printed in a book. As we advance, we learn new ways of doing things that we thought just a year back was impossible. Stop taking everthing as a personal threat to your manhood. One day, someone will come out with another book and will show you how to improve antenna effciencies from 50% to maybe 70%, who knows, but not if we accept everything as it is. People have always looked down on others to dared to challenge the way things were, until they proved themselves. Hell the exsistance of this country is proof of that, but we have all become complacient...no future in that.

As a caveat'... there has been no name calling, no one singled out, and all the words above are mine, mispelled or not, no animals were harmed in this writing, and batteries are NOT included. Taxes ,tags and title fees extra. Lighten up guys....challenge the system, it might be you that makes the next major break thru!

73 to all and to all a good nite!
de W4LGH - Alan
http://www.w4lgh.com
Reply to a comment by : K6IOU on 2007-02-28

With all due respect Al [W4LGH], the issues being discussed here and contradictory to some of your statements are well covered in the ARRL Antenna Handbook . . . a reference book that all hams should have, study, and attempt to understand. I think it is fair to say that the Handbook is a culmination of a hundred years or so of math, research and antenna experimentation. The issues discussed have been studied and tested in the real world by a wide variety of experts in the field. It includes both the theoretical and 'real world' data. You are disputing some of the most basic concepts of antenna design and operation, concepts that have been proven time and time again. How can this be? Perhaps we [antenna experimenters] would be even further ahead if mis-information such as yours was not continually espoused as truth. DON K6IOU
Reply to a comment by : KD2BD on 2007-02-28

W4LGH wrote: >> John, KD2BD wrote..."It's not an issue of belief. >> It's not an issue of blind faith. What we're >> discussing isn't black magic, voodoo, or religion. >> Its Science." > > Here we go with this perfect world again. They are > THEORIES in Science/Physics! Does your transmitter operate through proven theories of math and science, or through an arbitrary belief system? > In physics, the term theory is generally used for > a "mathematical framework" - derived from a small > set of basic principles... Thanks for the explanation. However, you lifted it directly from Wikipedia without citing it as a source. Sad. Very sad... 73, de John, KD2BD
Reply to a comment by : W4LGH on 2007-02-28

John, KD2BD wrote..."It's not an issue of belief. It's not an issue of blind faith. What we're discussing isn't black magic, voodoo, or religion. Its Science." Here we go with this perfect world again. They are THEORIES in Science/Physics! In physics, the term theory is generally used for a "mathematical framework", derived from a small set of basic principles (usually symmetries - like equality of locations in space or in time, or identity of electrons, etc), which is capable of producing experimental "predictions" for a given category of physical systems. A good example is electromagnetic theory, which encompasses the results that can be derived from gauge symmetry (sometimes called gauge invariance) in a form of a few equations called Maxwell's equations. Another name for this theory is classical electromagnetism. Note that the specific theoretical aspects of classical electromagnetic theory, which have been consistently and successfully replicated for well over a century, are termed "laws of electromagnetism", reflecting the fact that they are today "taken as granted". Within electromagnetic theory generally, there are numerous hypotheses about how electromagnetism applies to "specific situations". Many of these hypotheses are already considered to be adequately tested, with "new ones always in the making", and perhaps untested as yet. So do what you want, take what has been said for the past 100 years for granted, or understand that the math does not fit every "specific situation" or go back to your perfect world, and totally believe that the "LAWS of ELECTROMAGNETISM" are and will always be the same for every application, without any chance of improvement. Boy , where would we be today, if no one ever challenged previous theories and accepted things for the way they were. We'd still be in the dark ages! Certainly wouldn't be any Ham radio, tv, internet... Thank GOD for all those who dared to challenge and make improvements, and new developements, or we would be 100 years behind. If you always do what you have always done, you will always get what you have always gotten. Now there's a fact for you! This is getting old now, for there is a serious lack of imagination for without which, there can be no future! 73 de W4LGH - Alan http://www.w4lgh.com
Reply to a comment by : KD2BD on 2007-02-28

W4EF wrote: > W4LGH wrote: >> >> walk alone it and watch it light! Coax is shielded >> and technically does NOT radiate, you can have >> common mode currents ride the shield back into the >> shack, especially if your antenna is not resonant, >> but this energy is rarely if ever radiated, >> therefore it can NOT be tuned into the antenna >> system. > > Alan, this just simply isn't true. By definition, > common-mode current flows on the outside of the coax > shield. It always causes radiation. And besides, > common-mode current is a red herring with regard to > this debate. Antenna feedpoint mismatch doesn't > automatically imply common mode feedline current. > You can have very high VSWR on both coax and > open-wire lines without having feeder current > imbalance (i.e. common-mode current). > > Your comments are so off base on all of this stuff, > I simply don't know where to begin. Agreed. Current flow on the outside of the coax's shield is NOT the result of an impedance mismatch at the feed point, or the antenna being off resonance. It is the result of feeding a balanced antenna with an unbalanced transmission line. When we feed a perfectly balanced dipole (and it doesn't even have to be resonant), and wish to maintain its balance, we feed each half with equal and opposite voltages and currents. (Differential feed.) If we could feed just one side of the dipole (with respect to ground) and see what happens in slow motion, we would see that as the RF voltage begins to rise in a positive direction on the left side of the dipole, an equal and opposite voltage will start to develop on the right. This is not unlike the way a child's seesaw operates. If we push down on one end, the other end moves up by an equal amount. We cannot push down or lift both ends at the same time with the same amount of force and expect the seesaw to move. A transmitter places the shield of its coaxial feed at the same potential as its chassis, close to what IT considers to be an RF ground. This potential is maintained all the way to the end of the feed line, IF it is terminated in an unbalanced load, regardless of the impedance. What happens when we feed a dipole with coax? Remember that neither side of the dipole's feed point is at RF ground potential. If, at one instant of time, we apply +70 volts through the inner conductor to the right side of the dipole, left side will respond by developing -70 volts. Connecting the coax shield directly to either side of the dipole places an RF voltage on the shield where none should exist. This improper feed arrangement causes imbalance in the antenna, radiation and current flow along the outside of the shield of the line, and could lead to "RF feedback" and "RF burn" situations in the shack. The good news is that a balun at the feed point will help alleviate the problem. However, unless the coax is brought down exactly perpendicular with respect to the dipole, it will tend to interact (slightly couple to) one side of the dipole more than the other, resulting in a slight imbalance of the antenna, and some RF current flow along the outside of the coax's shield below the point of the balun due to this coupling. What if we were to feed the dipole with balanced line? First of all, is the dipole perfectly balanced? (Are both halves under the EXACT same influence of the ground and other surrounding objects?) Probably not. Is the feedline run exactly perpendicular to the antenna (as was needed in the case with coax) and kept far away from influencing objects? If either one of these conditions are not fully met, then the antenna SYSTEM is not perfectly balanced, even though your balanced tuner is mistakingly assuming it is! I think the issues that affect balanced lines can be minimized somewhat by simply twisting the line, maybe one turn every couple of feet. This will tend to give each leg a fairly equal opportunity to couple into one side of the dipole or the other, minimizing any "bias" toward any one side. W4LGH wrote: > You guys do whatever you want to do, believe whatever > you want to believe. It's not an issue of belief. It's not an issue of blind faith. What we're discussing isn't black magic, voodoo, or religion. It's science. You can BELIEVE that open wire line "becomes part of the antenna" while coax does not, and that a variable impedance matching device connected to a coaxial transmission line does nothing more than "fool the transmitter"... But that simply does not make it a REALITY. 73, de John, KD2BD
Reply to a comment by : W4EF on 2007-02-27

W4LGH wrote: >> walk alone it and watch it light! Coax is shielded and technically does NOT radiate, you can have common mode currents ride the shield back into the shack, especially if your antenna is not resonant, but this energy is rarely if ever radiated, therefore it can NOT be tuned into the antenna system. << Alan, this just simply isn't true. By definition, common-mode current flows on the outside of the coax shield. It always causes radiation. And besides, common-mode current is a red herring with regard to this debate. Antenna feedpoint mismatch doesn't automatically imply common mode feedline current. You can have very high VSWR on both coax and open-wire lines without having feeder current imbalance (i.e. common-mode current). Your comments are so off base on all of this stuff, I simply don't know where to begin. Because, I am working 12 to 14 hour days on my day job, I just don't have time to thoroughly respond to all of the wrong-headed ideas you are presenting here, so I suggest you do the following "real world experiment": Since you hold Walt Maxwell in such high esteem (as do I), send him a synopsys of all your claims in this thread. I'd bet the ranch that he will take exception to much of what you are claiming, especially your notions of common-mode current and antenna resonance. Thanks for the spirited debate. Gotta go (work is calling). 73, Mike W4EF.........................
Reply to a comment by : W4LGH on 2007-02-27

KD2BD writes... "But, remember: This isn't about loss. :-) It's about a claim that a variable impedance matching device at the transmitter operates in a different manner depending on whether the antenna system is coax or open-wire fed, and that open-wire feed "becomes part of the antenna", whereas coax does not. Why the double-standard?" There is no double standard, it is 2 complely different feed systems. Open or balanced line has comsiderable less loss, its non-shielded so it can and does radiate. Simple proof test there too. Take a floursent bulb out and hold it next to the feed line , walk alone it and watch it light! Coax is shielded and technically does NOT radiate, you can have common mode currents ride the shield back into the shack, especially if your antenna is not resonant, but this energy is rarely if ever radiated, therefore it can NOT be tuned into the antenna system. The balanced feed line can and does radiate, so it can be effectively tuned into the antenna system. So there is no dual standard, its 2 completely different ways of getting your RF to the antenna. One works ok with acceptable trade off's, and the other one doesn't. 73 de W4LGH - Alan http://www.w4lgh.com And I am really done this time. This is getting way to old now.
Reply to a comment by : W4LGH on 2007-02-27

K9IUQ wrote~"Finally something we can agree on."~ Now thats damn scary! There is nothing magical about any antenna. If what you have works for you ,then so be it! All antennas are trade off's, even the resonant dipole, you trade off use on other bands. I have the luxury of having resonant dipoles for the major bands I work, my benchmarks so me more power being radiated, and higher receive signals. The losses were to great using a tuner inside for me.
Reply to a comment by : K9IUQ on 2007-02-27

W4LGH says: f you put something up, and it seems to work great, and you can talk to everyone you hear, this is NOT a BENCHMARK...as you don't know who you are NOT hearing. .................................................... Finally something we can agree on. When testing antennas you should always test a new antenna against a known well performing antenna. As one who has put up (and taken down) over a hundred different antennas in his lifetime, the well used term "I can work them if I can hear em " is NOT a benchmark. I have tested your valued resonant coax fed dipole against MANY other antennas in my lifetime. Contrary to what you believe I am not an idiot. Having tested and used over a hundred different antennas, resonant, non resonant and even your valued trap dipole, I can assure you the resonant coax dipole has NO magical properties over many other antennas with or without a tuner. If a resonant coax dipole was magical, better than other antennas, I would be using one. Alas it is not so, hence my present antenna farm looks much like Walter Maxwell's. Not because Walter said so BUT I did my own bencharks thru many years and proved to myself what works best. K9IUQ
K9IUQ2007-02-28
RE: Benchmarks
K6IOU says
With all due respect Al [W4LGH],
You are disputing some of the most basic concepts of antenna design and operation, concepts that have been proven time and time again.

How can this be?

........................................................
This a MOST interesting question, one I have been trying to figure out for 47 years. The Antenna Truths are there for us all to read. So why do Hams like W4LGH continue to spew myths and untruths? Certainly Al is not dumb, he says is a "BroadCast Engineer", he must have *some* education in antenna theory.

So why does he believe the way he does? Contrary to what has been proven time and again in the antenna literature. Is it because he *thinks* he is smarter than all the antenna books? Is his ego so strong he just has to be right, never admitting he could be wrong.

I have heard countless discussions on the air that spew the same myths and untruths that we have heard Al say.

WHY????

There must be an answer somewhere.

Stan K9IUQ

Reply to a comment by : K6IOU on 2007-02-28

Hi again Al [W4LGH], On a positive note . . . you did a very nice job with your website. Great pics, organization. Certainly a station to be proud of. I also agree with you on your choice of audio: I also use a Behringer mixer and studio mic [Oktava MC 012]. DON K6IOU
Reply to a comment by : K6IOU on 2007-02-28

With all due respect Al [W4LGH], the issues being discussed here and contradictory to some of your statements are well covered in the ARRL Antenna Handbook . . . a reference book that all hams should have, study, and attempt to understand. I think it is fair to say that the Handbook is a culmination of a hundred years or so of math, research and antenna experimentation. The issues discussed have been studied and tested in the real world by a wide variety of experts in the field. It includes both the theoretical and 'real world' data. You are disputing some of the most basic concepts of antenna design and operation, concepts that have been proven time and time again. How can this be? Perhaps we [antenna experimenters] would be even further ahead if mis-information such as yours was not continually espoused as truth. DON K6IOU
Reply to a comment by : KD2BD on 2007-02-28

W4LGH wrote: >> John, KD2BD wrote..."It's not an issue of belief. >> It's not an issue of blind faith. What we're >> discussing isn't black magic, voodoo, or religion. >> Its Science." > > Here we go with this perfect world again. They are > THEORIES in Science/Physics! Does your transmitter operate through proven theories of math and science, or through an arbitrary belief system? > In physics, the term theory is generally used for > a "mathematical framework" - derived from a small > set of basic principles... Thanks for the explanation. However, you lifted it directly from Wikipedia without citing it as a source. Sad. Very sad... 73, de John, KD2BD
Reply to a comment by : W4LGH on 2007-02-28

John, KD2BD wrote..."It's not an issue of belief. It's not an issue of blind faith. What we're discussing isn't black magic, voodoo, or religion. Its Science." Here we go with this perfect world again. They are THEORIES in Science/Physics! In physics, the term theory is generally used for a "mathematical framework", derived from a small set of basic principles (usually symmetries - like equality of locations in space or in time, or identity of electrons, etc), which is capable of producing experimental "predictions" for a given category of physical systems. A good example is electromagnetic theory, which encompasses the results that can be derived from gauge symmetry (sometimes called gauge invariance) in a form of a few equations called Maxwell's equations. Another name for this theory is classical electromagnetism. Note that the specific theoretical aspects of classical electromagnetic theory, which have been consistently and successfully replicated for well over a century, are termed "laws of electromagnetism", reflecting the fact that they are today "taken as granted". Within electromagnetic theory generally, there are numerous hypotheses about how electromagnetism applies to "specific situations". Many of these hypotheses are already considered to be adequately tested, with "new ones always in the making", and perhaps untested as yet. So do what you want, take what has been said for the past 100 years for granted, or understand that the math does not fit every "specific situation" or go back to your perfect world, and totally believe that the "LAWS of ELECTROMAGNETISM" are and will always be the same for every application, without any chance of improvement. Boy , where would we be today, if no one ever challenged previous theories and accepted things for the way they were. We'd still be in the dark ages! Certainly wouldn't be any Ham radio, tv, internet... Thank GOD for all those who dared to challenge and make improvements, and new developements, or we would be 100 years behind. If you always do what you have always done, you will always get what you have always gotten. Now there's a fact for you! This is getting old now, for there is a serious lack of imagination for without which, there can be no future! 73 de W4LGH - Alan http://www.w4lgh.com
Reply to a comment by : KD2BD on 2007-02-28

W4EF wrote: > W4LGH wrote: >> >> walk alone it and watch it light! Coax is shielded >> and technically does NOT radiate, you can have >> common mode currents ride the shield back into the >> shack, especially if your antenna is not resonant, >> but this energy is rarely if ever radiated, >> therefore it can NOT be tuned into the antenna >> system. > > Alan, this just simply isn't true. By definition, > common-mode current flows on the outside of the coax > shield. It always causes radiation. And besides, > common-mode current is a red herring with regard to > this debate. Antenna feedpoint mismatch doesn't > automatically imply common mode feedline current. > You can have very high VSWR on both coax and > open-wire lines without having feeder current > imbalance (i.e. common-mode current). > > Your comments are so off base on all of this stuff, > I simply don't know where to begin. Agreed. Current flow on the outside of the coax's shield is NOT the result of an impedance mismatch at the feed point, or the antenna being off resonance. It is the result of feeding a balanced antenna with an unbalanced transmission line. When we feed a perfectly balanced dipole (and it doesn't even have to be resonant), and wish to maintain its balance, we feed each half with equal and opposite voltages and currents. (Differential feed.) If we could feed just one side of the dipole (with respect to ground) and see what happens in slow motion, we would see that as the RF voltage begins to rise in a positive direction on the left side of the dipole, an equal and opposite voltage will start to develop on the right. This is not unlike the way a child's seesaw operates. If we push down on one end, the other end moves up by an equal amount. We cannot push down or lift both ends at the same time with the same amount of force and expect the seesaw to move. A transmitter places the shield of its coaxial feed at the same potential as its chassis, close to what IT considers to be an RF ground. This potential is maintained all the way to the end of the feed line, IF it is terminated in an unbalanced load, regardless of the impedance. What happens when we feed a dipole with coax? Remember that neither side of the dipole's feed point is at RF ground potential. If, at one instant of time, we apply +70 volts through the inner conductor to the right side of the dipole, left side will respond by developing -70 volts. Connecting the coax shield directly to either side of the dipole places an RF voltage on the shield where none should exist. This improper feed arrangement causes imbalance in the antenna, radiation and current flow along the outside of the shield of the line, and could lead to "RF feedback" and "RF burn" situations in the shack. The good news is that a balun at the feed point will help alleviate the problem. However, unless the coax is brought down exactly perpendicular with respect to the dipole, it will tend to interact (slightly couple to) one side of the dipole more than the other, resulting in a slight imbalance of the antenna, and some RF current flow along the outside of the coax's shield below the point of the balun due to this coupling. What if we were to feed the dipole with balanced line? First of all, is the dipole perfectly balanced? (Are both halves under the EXACT same influence of the ground and other surrounding objects?) Probably not. Is the feedline run exactly perpendicular to the antenna (as was needed in the case with coax) and kept far away from influencing objects? If either one of these conditions are not fully met, then the antenna SYSTEM is not perfectly balanced, even though your balanced tuner is mistakingly assuming it is! I think the issues that affect balanced lines can be minimized somewhat by simply twisting the line, maybe one turn every couple of feet. This will tend to give each leg a fairly equal opportunity to couple into one side of the dipole or the other, minimizing any "bias" toward any one side. W4LGH wrote: > You guys do whatever you want to do, believe whatever > you want to believe. It's not an issue of belief. It's not an issue of blind faith. What we're discussing isn't black magic, voodoo, or religion. It's science. You can BELIEVE that open wire line "becomes part of the antenna" while coax does not, and that a variable impedance matching device connected to a coaxial transmission line does nothing more than "fool the transmitter"... But that simply does not make it a REALITY. 73, de John, KD2BD
Reply to a comment by : W4EF on 2007-02-27

W4LGH wrote: >> walk alone it and watch it light! Coax is shielded and technically does NOT radiate, you can have common mode currents ride the shield back into the shack, especially if your antenna is not resonant, but this energy is rarely if ever radiated, therefore it can NOT be tuned into the antenna system. << Alan, this just simply isn't true. By definition, common-mode current flows on the outside of the coax shield. It always causes radiation. And besides, common-mode current is a red herring with regard to this debate. Antenna feedpoint mismatch doesn't automatically imply common mode feedline current. You can have very high VSWR on both coax and open-wire lines without having feeder current imbalance (i.e. common-mode current). Your comments are so off base on all of this stuff, I simply don't know where to begin. Because, I am working 12 to 14 hour days on my day job, I just don't have time to thoroughly respond to all of the wrong-headed ideas you are presenting here, so I suggest you do the following "real world experiment": Since you hold Walt Maxwell in such high esteem (as do I), send him a synopsys of all your claims in this thread. I'd bet the ranch that he will take exception to much of what you are claiming, especially your notions of common-mode current and antenna resonance. Thanks for the spirited debate. Gotta go (work is calling). 73, Mike W4EF.........................
Reply to a comment by : W4LGH on 2007-02-27

KD2BD writes... "But, remember: This isn't about loss. :-) It's about a claim that a variable impedance matching device at the transmitter operates in a different manner depending on whether the antenna system is coax or open-wire fed, and that open-wire feed "becomes part of the antenna", whereas coax does not. Why the double-standard?" There is no double standard, it is 2 complely different feed systems. Open or balanced line has comsiderable less loss, its non-shielded so it can and does radiate. Simple proof test there too. Take a floursent bulb out and hold it next to the feed line , walk alone it and watch it light! Coax is shielded and technically does NOT radiate, you can have common mode currents ride the shield back into the shack, especially if your antenna is not resonant, but this energy is rarely if ever radiated, therefore it can NOT be tuned into the antenna system. The balanced feed line can and does radiate, so it can be effectively tuned into the antenna system. So there is no dual standard, its 2 completely different ways of getting your RF to the antenna. One works ok with acceptable trade off's, and the other one doesn't. 73 de W4LGH - Alan http://www.w4lgh.com And I am really done this time. This is getting way to old now.
Reply to a comment by : W4LGH on 2007-02-27

K9IUQ wrote~"Finally something we can agree on."~ Now thats damn scary! There is nothing magical about any antenna. If what you have works for you ,then so be it! All antennas are trade off's, even the resonant dipole, you trade off use on other bands. I have the luxury of having resonant dipoles for the major bands I work, my benchmarks so me more power being radiated, and higher receive signals. The losses were to great using a tuner inside for me.
Reply to a comment by : K9IUQ on 2007-02-27

W4LGH says: f you put something up, and it seems to work great, and you can talk to everyone you hear, this is NOT a BENCHMARK...as you don't know who you are NOT hearing. .................................................... Finally something we can agree on. When testing antennas you should always test a new antenna against a known well performing antenna. As one who has put up (and taken down) over a hundred different antennas in his lifetime, the well used term "I can work them if I can hear em " is NOT a benchmark. I have tested your valued resonant coax fed dipole against MANY other antennas in my lifetime. Contrary to what you believe I am not an idiot. Having tested and used over a hundred different antennas, resonant, non resonant and even your valued trap dipole, I can assure you the resonant coax dipole has NO magical properties over many other antennas with or without a tuner. If a resonant coax dipole was magical, better than other antennas, I would be using one. Alas it is not so, hence my present antenna farm looks much like Walter Maxwell's. Not because Walter said so BUT I did my own bencharks thru many years and proved to myself what works best. K9IUQ
K6IOU2007-02-28
RE: Benchmarks
Hi again Al [W4LGH],

On a positive note . . . you did a very nice job with your website. Great pics, organization. Certainly a station to be proud of.

I also agree with you on your choice of audio: I also use a Behringer mixer and studio mic [Oktava MC 012].

DON
K6IOU
Reply to a comment by : K6IOU on 2007-02-28

With all due respect Al [W4LGH], the issues being discussed here and contradictory to some of your statements are well covered in the ARRL Antenna Handbook . . . a reference book that all hams should have, study, and attempt to understand. I think it is fair to say that the Handbook is a culmination of a hundred years or so of math, research and antenna experimentation. The issues discussed have been studied and tested in the real world by a wide variety of experts in the field. It includes both the theoretical and 'real world' data. You are disputing some of the most basic concepts of antenna design and operation, concepts that have been proven time and time again. How can this be? Perhaps we [antenna experimenters] would be even further ahead if mis-information such as yours was not continually espoused as truth. DON K6IOU
Reply to a comment by : KD2BD on 2007-02-28

W4LGH wrote: >> John, KD2BD wrote..."It's not an issue of belief. >> It's not an issue of blind faith. What we're >> discussing isn't black magic, voodoo, or religion. >> Its Science." > > Here we go with this perfect world again. They are > THEORIES in Science/Physics! Does your transmitter operate through proven theories of math and science, or through an arbitrary belief system? > In physics, the term theory is generally used for > a "mathematical framework" - derived from a small > set of basic principles... Thanks for the explanation. However, you lifted it directly from Wikipedia without citing it as a source. Sad. Very sad... 73, de John, KD2BD
Reply to a comment by : W4LGH on 2007-02-28

John, KD2BD wrote..."It's not an issue of belief. It's not an issue of blind faith. What we're discussing isn't black magic, voodoo, or religion. Its Science." Here we go with this perfect world again. They are THEORIES in Science/Physics! In physics, the term theory is generally used for a "mathematical framework", derived from a small set of basic principles (usually symmetries - like equality of locations in space or in time, or identity of electrons, etc), which is capable of producing experimental "predictions" for a given category of physical systems. A good example is electromagnetic theory, which encompasses the results that can be derived from gauge symmetry (sometimes called gauge invariance) in a form of a few equations called Maxwell's equations. Another name for this theory is classical electromagnetism. Note that the specific theoretical aspects of classical electromagnetic theory, which have been consistently and successfully replicated for well over a century, are termed "laws of electromagnetism", reflecting the fact that they are today "taken as granted". Within electromagnetic theory generally, there are numerous hypotheses about how electromagnetism applies to "specific situations". Many of these hypotheses are already considered to be adequately tested, with "new ones always in the making", and perhaps untested as yet. So do what you want, take what has been said for the past 100 years for granted, or understand that the math does not fit every "specific situation" or go back to your perfect world, and totally believe that the "LAWS of ELECTROMAGNETISM" are and will always be the same for every application, without any chance of improvement. Boy , where would we be today, if no one ever challenged previous theories and accepted things for the way they were. We'd still be in the dark ages! Certainly wouldn't be any Ham radio, tv, internet... Thank GOD for all those who dared to challenge and make improvements, and new developements, or we would be 100 years behind. If you always do what you have always done, you will always get what you have always gotten. Now there's a fact for you! This is getting old now, for there is a serious lack of imagination for without which, there can be no future! 73 de W4LGH - Alan http://www.w4lgh.com
Reply to a comment by : KD2BD on 2007-02-28

W4EF wrote: > W4LGH wrote: >> >> walk alone it and watch it light! Coax is shielded >> and technically does NOT radiate, you can have >> common mode currents ride the shield back into the >> shack, especially if your antenna is not resonant, >> but this energy is rarely if ever radiated, >> therefore it can NOT be tuned into the antenna >> system. > > Alan, this just simply isn't true. By definition, > common-mode current flows on the outside of the coax > shield. It always causes radiation. And besides, > common-mode current is a red herring with regard to > this debate. Antenna feedpoint mismatch doesn't > automatically imply common mode feedline current. > You can have very high VSWR on both coax and > open-wire lines without having feeder current > imbalance (i.e. common-mode current). > > Your comments are so off base on all of this stuff, > I simply don't know where to begin. Agreed. Current flow on the outside of the coax's shield is NOT the result of an impedance mismatch at the feed point, or the antenna being off resonance. It is the result of feeding a balanced antenna with an unbalanced transmission line. When we feed a perfectly balanced dipole (and it doesn't even have to be resonant), and wish to maintain its balance, we feed each half with equal and opposite voltages and currents. (Differential feed.) If we could feed just one side of the dipole (with respect to ground) and see what happens in slow motion, we would see that as the RF voltage begins to rise in a positive direction on the left side of the dipole, an equal and opposite voltage will start to develop on the right. This is not unlike the way a child's seesaw operates. If we push down on one end, the other end moves up by an equal amount. We cannot push down or lift both ends at the same time with the same amount of force and expect the seesaw to move. A transmitter places the shield of its coaxial feed at the same potential as its chassis, close to what IT considers to be an RF ground. This potential is maintained all the way to the end of the feed line, IF it is terminated in an unbalanced load, regardless of the impedance. What happens when we feed a dipole with coax? Remember that neither side of the dipole's feed point is at RF ground potential. If, at one instant of time, we apply +70 volts through the inner conductor to the right side of the dipole, left side will respond by developing -70 volts. Connecting the coax shield directly to either side of the dipole places an RF voltage on the shield where none should exist. This improper feed arrangement causes imbalance in the antenna, radiation and current flow along the outside of the shield of the line, and could lead to "RF feedback" and "RF burn" situations in the shack. The good news is that a balun at the feed point will help alleviate the problem. However, unless the coax is brought down exactly perpendicular with respect to the dipole, it will tend to interact (slightly couple to) one side of the dipole more than the other, resulting in a slight imbalance of the antenna, and some RF current flow along the outside of the coax's shield below the point of the balun due to this coupling. What if we were to feed the dipole with balanced line? First of all, is the dipole perfectly balanced? (Are both halves under the EXACT same influence of the ground and other surrounding objects?) Probably not. Is the feedline run exactly perpendicular to the antenna (as was needed in the case with coax) and kept far away from influencing objects? If either one of these conditions are not fully met, then the antenna SYSTEM is not perfectly balanced, even though your balanced tuner is mistakingly assuming it is! I think the issues that affect balanced lines can be minimized somewhat by simply twisting the line, maybe one turn every couple of feet. This will tend to give each leg a fairly equal opportunity to couple into one side of the dipole or the other, minimizing any "bias" toward any one side. W4LGH wrote: > You guys do whatever you want to do, believe whatever > you want to believe. It's not an issue of belief. It's not an issue of blind faith. What we're discussing isn't black magic, voodoo, or religion. It's science. You can BELIEVE that open wire line "becomes part of the antenna" while coax does not, and that a variable impedance matching device connected to a coaxial transmission line does nothing more than "fool the transmitter"... But that simply does not make it a REALITY. 73, de John, KD2BD
Reply to a comment by : W4EF on 2007-02-27

W4LGH wrote: >> walk alone it and watch it light! Coax is shielded and technically does NOT radiate, you can have common mode currents ride the shield back into the shack, especially if your antenna is not resonant, but this energy is rarely if ever radiated, therefore it can NOT be tuned into the antenna system. << Alan, this just simply isn't true. By definition, common-mode current flows on the outside of the coax shield. It always causes radiation. And besides, common-mode current is a red herring with regard to this debate. Antenna feedpoint mismatch doesn't automatically imply common mode feedline current. You can have very high VSWR on both coax and open-wire lines without having feeder current imbalance (i.e. common-mode current). Your comments are so off base on all of this stuff, I simply don't know where to begin. Because, I am working 12 to 14 hour days on my day job, I just don't have time to thoroughly respond to all of the wrong-headed ideas you are presenting here, so I suggest you do the following "real world experiment": Since you hold Walt Maxwell in such high esteem (as do I), send him a synopsys of all your claims in this thread. I'd bet the ranch that he will take exception to much of what you are claiming, especially your notions of common-mode current and antenna resonance. Thanks for the spirited debate. Gotta go (work is calling). 73, Mike W4EF.........................
Reply to a comment by : W4LGH on 2007-02-27

KD2BD writes... "But, remember: This isn't about loss. :-) It's about a claim that a variable impedance matching device at the transmitter operates in a different manner depending on whether the antenna system is coax or open-wire fed, and that open-wire feed "becomes part of the antenna", whereas coax does not. Why the double-standard?" There is no double standard, it is 2 complely different feed systems. Open or balanced line has comsiderable less loss, its non-shielded so it can and does radiate. Simple proof test there too. Take a floursent bulb out and hold it next to the feed line , walk alone it and watch it light! Coax is shielded and technically does NOT radiate, you can have common mode currents ride the shield back into the shack, especially if your antenna is not resonant, but this energy is rarely if ever radiated, therefore it can NOT be tuned into the antenna system. The balanced feed line can and does radiate, so it can be effectively tuned into the antenna system. So there is no dual standard, its 2 completely different ways of getting your RF to the antenna. One works ok with acceptable trade off's, and the other one doesn't. 73 de W4LGH - Alan http://www.w4lgh.com And I am really done this time. This is getting way to old now.
Reply to a comment by : W4LGH on 2007-02-27

K9IUQ wrote~"Finally something we can agree on."~ Now thats damn scary! There is nothing magical about any antenna. If what you have works for you ,then so be it! All antennas are trade off's, even the resonant dipole, you trade off use on other bands. I have the luxury of having resonant dipoles for the major bands I work, my benchmarks so me more power being radiated, and higher receive signals. The losses were to great using a tuner inside for me.
Reply to a comment by : K9IUQ on 2007-02-27

W4LGH says: f you put something up, and it seems to work great, and you can talk to everyone you hear, this is NOT a BENCHMARK...as you don't know who you are NOT hearing. .................................................... Finally something we can agree on. When testing antennas you should always test a new antenna against a known well performing antenna. As one who has put up (and taken down) over a hundred different antennas in his lifetime, the well used term "I can work them if I can hear em " is NOT a benchmark. I have tested your valued resonant coax fed dipole against MANY other antennas in my lifetime. Contrary to what you believe I am not an idiot. Having tested and used over a hundred different antennas, resonant, non resonant and even your valued trap dipole, I can assure you the resonant coax dipole has NO magical properties over many other antennas with or without a tuner. If a resonant coax dipole was magical, better than other antennas, I would be using one. Alas it is not so, hence my present antenna farm looks much like Walter Maxwell's. Not because Walter said so BUT I did my own bencharks thru many years and proved to myself what works best. K9IUQ
K6IOU2007-02-28
RE: Benchmarks
With all due respect Al [W4LGH], the issues being discussed here and contradictory to some of your statements are well covered in the ARRL Antenna Handbook . . . a reference book that all hams should have, study, and attempt to understand.

I think it is fair to say that the Handbook is a culmination of a hundred years or so of math, research and antenna experimentation. The issues discussed have been studied and tested in the real world by a wide variety of experts in the field. It includes both the theoretical and 'real world' data.

You are disputing some of the most basic concepts of antenna design and operation, concepts that have been proven time and time again.

How can this be? Perhaps we [antenna experimenters] would be even further ahead if mis-information such as yours was not continually espoused as truth.

DON
K6IOU
Reply to a comment by : KD2BD on 2007-02-28

W4LGH wrote: >> John, KD2BD wrote..."It's not an issue of belief. >> It's not an issue of blind faith. What we're >> discussing isn't black magic, voodoo, or religion. >> Its Science." > > Here we go with this perfect world again. They are > THEORIES in Science/Physics! Does your transmitter operate through proven theories of math and science, or through an arbitrary belief system? > In physics, the term theory is generally used for > a "mathematical framework" - derived from a small > set of basic principles... Thanks for the explanation. However, you lifted it directly from Wikipedia without citing it as a source. Sad. Very sad... 73, de John, KD2BD
Reply to a comment by : W4LGH on 2007-02-28

John, KD2BD wrote..."It's not an issue of belief. It's not an issue of blind faith. What we're discussing isn't black magic, voodoo, or religion. Its Science." Here we go with this perfect world again. They are THEORIES in Science/Physics! In physics, the term theory is generally used for a "mathematical framework", derived from a small set of basic principles (usually symmetries - like equality of locations in space or in time, or identity of electrons, etc), which is capable of producing experimental "predictions" for a given category of physical systems. A good example is electromagnetic theory, which encompasses the results that can be derived from gauge symmetry (sometimes called gauge invariance) in a form of a few equations called Maxwell's equations. Another name for this theory is classical electromagnetism. Note that the specific theoretical aspects of classical electromagnetic theory, which have been consistently and successfully replicated for well over a century, are termed "laws of electromagnetism", reflecting the fact that they are today "taken as granted". Within electromagnetic theory generally, there are numerous hypotheses about how electromagnetism applies to "specific situations". Many of these hypotheses are already considered to be adequately tested, with "new ones always in the making", and perhaps untested as yet. So do what you want, take what has been said for the past 100 years for granted, or understand that the math does not fit every "specific situation" or go back to your perfect world, and totally believe that the "LAWS of ELECTROMAGNETISM" are and will always be the same for every application, without any chance of improvement. Boy , where would we be today, if no one ever challenged previous theories and accepted things for the way they were. We'd still be in the dark ages! Certainly wouldn't be any Ham radio, tv, internet... Thank GOD for all those who dared to challenge and make improvements, and new developements, or we would be 100 years behind. If you always do what you have always done, you will always get what you have always gotten. Now there's a fact for you! This is getting old now, for there is a serious lack of imagination for without which, there can be no future! 73 de W4LGH - Alan http://www.w4lgh.com
Reply to a comment by : KD2BD on 2007-02-28

W4EF wrote: > W4LGH wrote: >> >> walk alone it and watch it light! Coax is shielded >> and technically does NOT radiate, you can have >> common mode currents ride the shield back into the >> shack, especially if your antenna is not resonant, >> but this energy is rarely if ever radiated, >> therefore it can NOT be tuned into the antenna >> system. > > Alan, this just simply isn't true. By definition, > common-mode current flows on the outside of the coax > shield. It always causes radiation. And besides, > common-mode current is a red herring with regard to > this debate. Antenna feedpoint mismatch doesn't > automatically imply common mode feedline current. > You can have very high VSWR on both coax and > open-wire lines without having feeder current > imbalance (i.e. common-mode current). > > Your comments are so off base on all of this stuff, > I simply don't know where to begin. Agreed. Current flow on the outside of the coax's shield is NOT the result of an impedance mismatch at the feed point, or the antenna being off resonance. It is the result of feeding a balanced antenna with an unbalanced transmission line. When we feed a perfectly balanced dipole (and it doesn't even have to be resonant), and wish to maintain its balance, we feed each half with equal and opposite voltages and currents. (Differential feed.) If we could feed just one side of the dipole (with respect to ground) and see what happens in slow motion, we would see that as the RF voltage begins to rise in a positive direction on the left side of the dipole, an equal and opposite voltage will start to develop on the right. This is not unlike the way a child's seesaw operates. If we push down on one end, the other end moves up by an equal amount. We cannot push down or lift both ends at the same time with the same amount of force and expect the seesaw to move. A transmitter places the shield of its coaxial feed at the same potential as its chassis, close to what IT considers to be an RF ground. This potential is maintained all the way to the end of the feed line, IF it is terminated in an unbalanced load, regardless of the impedance. What happens when we feed a dipole with coax? Remember that neither side of the dipole's feed point is at RF ground potential. If, at one instant of time, we apply +70 volts through the inner conductor to the right side of the dipole, left side will respond by developing -70 volts. Connecting the coax shield directly to either side of the dipole places an RF voltage on the shield where none should exist. This improper feed arrangement causes imbalance in the antenna, radiation and current flow along the outside of the shield of the line, and could lead to "RF feedback" and "RF burn" situations in the shack. The good news is that a balun at the feed point will help alleviate the problem. However, unless the coax is brought down exactly perpendicular with respect to the dipole, it will tend to interact (slightly couple to) one side of the dipole more than the other, resulting in a slight imbalance of the antenna, and some RF current flow along the outside of the coax's shield below the point of the balun due to this coupling. What if we were to feed the dipole with balanced line? First of all, is the dipole perfectly balanced? (Are both halves under the EXACT same influence of the ground and other surrounding objects?) Probably not. Is the feedline run exactly perpendicular to the antenna (as was needed in the case with coax) and kept far away from influencing objects? If either one of these conditions are not fully met, then the antenna SYSTEM is not perfectly balanced, even though your balanced tuner is mistakingly assuming it is! I think the issues that affect balanced lines can be minimized somewhat by simply twisting the line, maybe one turn every couple of feet. This will tend to give each leg a fairly equal opportunity to couple into one side of the dipole or the other, minimizing any "bias" toward any one side. W4LGH wrote: > You guys do whatever you want to do, believe whatever > you want to believe. It's not an issue of belief. It's not an issue of blind faith. What we're discussing isn't black magic, voodoo, or religion. It's science. You can BELIEVE that open wire line "becomes part of the antenna" while coax does not, and that a variable impedance matching device connected to a coaxial transmission line does nothing more than "fool the transmitter"... But that simply does not make it a REALITY. 73, de John, KD2BD
Reply to a comment by : W4EF on 2007-02-27

W4LGH wrote: >> walk alone it and watch it light! Coax is shielded and technically does NOT radiate, you can have common mode currents ride the shield back into the shack, especially if your antenna is not resonant, but this energy is rarely if ever radiated, therefore it can NOT be tuned into the antenna system. << Alan, this just simply isn't true. By definition, common-mode current flows on the outside of the coax shield. It always causes radiation. And besides, common-mode current is a red herring with regard to this debate. Antenna feedpoint mismatch doesn't automatically imply common mode feedline current. You can have very high VSWR on both coax and open-wire lines without having feeder current imbalance (i.e. common-mode current). Your comments are so off base on all of this stuff, I simply don't know where to begin. Because, I am working 12 to 14 hour days on my day job, I just don't have time to thoroughly respond to all of the wrong-headed ideas you are presenting here, so I suggest you do the following "real world experiment": Since you hold Walt Maxwell in such high esteem (as do I), send him a synopsys of all your claims in this thread. I'd bet the ranch that he will take exception to much of what you are claiming, especially your notions of common-mode current and antenna resonance. Thanks for the spirited debate. Gotta go (work is calling). 73, Mike W4EF.........................
Reply to a comment by : W4LGH on 2007-02-27

KD2BD writes... "But, remember: This isn't about loss. :-) It's about a claim that a variable impedance matching device at the transmitter operates in a different manner depending on whether the antenna system is coax or open-wire fed, and that open-wire feed "becomes part of the antenna", whereas coax does not. Why the double-standard?" There is no double standard, it is 2 complely different feed systems. Open or balanced line has comsiderable less loss, its non-shielded so it can and does radiate. Simple proof test there too. Take a floursent bulb out and hold it next to the feed line , walk alone it and watch it light! Coax is shielded and technically does NOT radiate, you can have common mode currents ride the shield back into the shack, especially if your antenna is not resonant, but this energy is rarely if ever radiated, therefore it can NOT be tuned into the antenna system. The balanced feed line can and does radiate, so it can be effectively tuned into the antenna system. So there is no dual standard, its 2 completely different ways of getting your RF to the antenna. One works ok with acceptable trade off's, and the other one doesn't. 73 de W4LGH - Alan http://www.w4lgh.com And I am really done this time. This is getting way to old now.
Reply to a comment by : W4LGH on 2007-02-27

K9IUQ wrote~"Finally something we can agree on."~ Now thats damn scary! There is nothing magical about any antenna. If what you have works for you ,then so be it! All antennas are trade off's, even the resonant dipole, you trade off use on other bands. I have the luxury of having resonant dipoles for the major bands I work, my benchmarks so me more power being radiated, and higher receive signals. The losses were to great using a tuner inside for me.
Reply to a comment by : K9IUQ on 2007-02-27

W4LGH says: f you put something up, and it seems to work great, and you can talk to everyone you hear, this is NOT a BENCHMARK...as you don't know who you are NOT hearing. .................................................... Finally something we can agree on. When testing antennas you should always test a new antenna against a known well performing antenna. As one who has put up (and taken down) over a hundred different antennas in his lifetime, the well used term "I can work them if I can hear em " is NOT a benchmark. I have tested your valued resonant coax fed dipole against MANY other antennas in my lifetime. Contrary to what you believe I am not an idiot. Having tested and used over a hundred different antennas, resonant, non resonant and even your valued trap dipole, I can assure you the resonant coax dipole has NO magical properties over many other antennas with or without a tuner. If a resonant coax dipole was magical, better than other antennas, I would be using one. Alas it is not so, hence my present antenna farm looks much like Walter Maxwell's. Not because Walter said so BUT I did my own bencharks thru many years and proved to myself what works best. K9IUQ
K9IUQ2007-02-28
Benchmarks
KD@BD says Thanks for the explanation. However, you lifted it directly from Wikipedia without citing it as a source.

Sad. Very sad...
.....................................................

WOW, I knew W4LGH didn't write it since it had perfect grammar and spelling. He lifted the WHOLE thing from WIKI. He didnt credit WIKI because he wanted us to think he wrote it.

Sad, Very Very Sad

Stan K9IUQ
KD2BD2007-02-28
RE: Benchmarks
W4LGH wrote:

>> John, KD2BD wrote..."It's not an issue of belief.
>> It's not an issue of blind faith. What we're
>> discussing isn't black magic, voodoo, or religion.
>> Its Science."
>
> Here we go with this perfect world again. They are
> THEORIES in Science/Physics!

Does your transmitter operate through proven theories of math and science, or through an arbitrary belief system?

> In physics, the term theory is generally used for
> a "mathematical framework" - derived from a small
> set of basic principles...

Thanks for the explanation. However, you lifted it directly from Wikipedia without citing it as a source.

Sad. Very sad...


73, de John, KD2BD
Reply to a comment by : W4LGH on 2007-02-28

John, KD2BD wrote..."It's not an issue of belief. It's not an issue of blind faith. What we're discussing isn't black magic, voodoo, or religion. Its Science." Here we go with this perfect world again. They are THEORIES in Science/Physics! In physics, the term theory is generally used for a "mathematical framework", derived from a small set of basic principles (usually symmetries - like equality of locations in space or in time, or identity of electrons, etc), which is capable of producing experimental "predictions" for a given category of physical systems. A good example is electromagnetic theory, which encompasses the results that can be derived from gauge symmetry (sometimes called gauge invariance) in a form of a few equations called Maxwell's equations. Another name for this theory is classical electromagnetism. Note that the specific theoretical aspects of classical electromagnetic theory, which have been consistently and successfully replicated for well over a century, are termed "laws of electromagnetism", reflecting the fact that they are today "taken as granted". Within electromagnetic theory generally, there are numerous hypotheses about how electromagnetism applies to "specific situations". Many of these hypotheses are already considered to be adequately tested, with "new ones always in the making", and perhaps untested as yet. So do what you want, take what has been said for the past 100 years for granted, or understand that the math does not fit every "specific situation" or go back to your perfect world, and totally believe that the "LAWS of ELECTROMAGNETISM" are and will always be the same for every application, without any chance of improvement. Boy , where would we be today, if no one ever challenged previous theories and accepted things for the way they were. We'd still be in the dark ages! Certainly wouldn't be any Ham radio, tv, internet... Thank GOD for all those who dared to challenge and make improvements, and new developements, or we would be 100 years behind. If you always do what you have always done, you will always get what you have always gotten. Now there's a fact for you! This is getting old now, for there is a serious lack of imagination for without which, there can be no future! 73 de W4LGH - Alan http://www.w4lgh.com
Reply to a comment by : KD2BD on 2007-02-28

W4EF wrote: > W4LGH wrote: >> >> walk alone it and watch it light! Coax is shielded >> and technically does NOT radiate, you can have >> common mode currents ride the shield back into the >> shack, especially if your antenna is not resonant, >> but this energy is rarely if ever radiated, >> therefore it can NOT be tuned into the antenna >> system. > > Alan, this just simply isn't true. By definition, > common-mode current flows on the outside of the coax > shield. It always causes radiation. And besides, > common-mode current is a red herring with regard to > this debate. Antenna feedpoint mismatch doesn't > automatically imply common mode feedline current. > You can have very high VSWR on both coax and > open-wire lines without having feeder current > imbalance (i.e. common-mode current). > > Your comments are so off base on all of this stuff, > I simply don't know where to begin. Agreed. Current flow on the outside of the coax's shield is NOT the result of an impedance mismatch at the feed point, or the antenna being off resonance. It is the result of feeding a balanced antenna with an unbalanced transmission line. When we feed a perfectly balanced dipole (and it doesn't even have to be resonant), and wish to maintain its balance, we feed each half with equal and opposite voltages and currents. (Differential feed.) If we could feed just one side of the dipole (with respect to ground) and see what happens in slow motion, we would see that as the RF voltage begins to rise in a positive direction on the left side of the dipole, an equal and opposite voltage will start to develop on the right. This is not unlike the way a child's seesaw operates. If we push down on one end, the other end moves up by an equal amount. We cannot push down or lift both ends at the same time with the same amount of force and expect the seesaw to move. A transmitter places the shield of its coaxial feed at the same potential as its chassis, close to what IT considers to be an RF ground. This potential is maintained all the way to the end of the feed line, IF it is terminated in an unbalanced load, regardless of the impedance. What happens when we feed a dipole with coax? Remember that neither side of the dipole's feed point is at RF ground potential. If, at one instant of time, we apply +70 volts through the inner conductor to the right side of the dipole, left side will respond by developing -70 volts. Connecting the coax shield directly to either side of the dipole places an RF voltage on the shield where none should exist. This improper feed arrangement causes imbalance in the antenna, radiation and current flow along the outside of the shield of the line, and could lead to "RF feedback" and "RF burn" situations in the shack. The good news is that a balun at the feed point will help alleviate the problem. However, unless the coax is brought down exactly perpendicular with respect to the dipole, it will tend to interact (slightly couple to) one side of the dipole more than the other, resulting in a slight imbalance of the antenna, and some RF current flow along the outside of the coax's shield below the point of the balun due to this coupling. What if we were to feed the dipole with balanced line? First of all, is the dipole perfectly balanced? (Are both halves under the EXACT same influence of the ground and other surrounding objects?) Probably not. Is the feedline run exactly perpendicular to the antenna (as was needed in the case with coax) and kept far away from influencing objects? If either one of these conditions are not fully met, then the antenna SYSTEM is not perfectly balanced, even though your balanced tuner is mistakingly assuming it is! I think the issues that affect balanced lines can be minimized somewhat by simply twisting the line, maybe one turn every couple of feet. This will tend to give each leg a fairly equal opportunity to couple into one side of the dipole or the other, minimizing any "bias" toward any one side. W4LGH wrote: > You guys do whatever you want to do, believe whatever > you want to believe. It's not an issue of belief. It's not an issue of blind faith. What we're discussing isn't black magic, voodoo, or religion. It's science. You can BELIEVE that open wire line "becomes part of the antenna" while coax does not, and that a variable impedance matching device connected to a coaxial transmission line does nothing more than "fool the transmitter"... But that simply does not make it a REALITY. 73, de John, KD2BD
Reply to a comment by : W4EF on 2007-02-27

W4LGH wrote: >> walk alone it and watch it light! Coax is shielded and technically does NOT radiate, you can have common mode currents ride the shield back into the shack, especially if your antenna is not resonant, but this energy is rarely if ever radiated, therefore it can NOT be tuned into the antenna system. << Alan, this just simply isn't true. By definition, common-mode current flows on the outside of the coax shield. It always causes radiation. And besides, common-mode current is a red herring with regard to this debate. Antenna feedpoint mismatch doesn't automatically imply common mode feedline current. You can have very high VSWR on both coax and open-wire lines without having feeder current imbalance (i.e. common-mode current). Your comments are so off base on all of this stuff, I simply don't know where to begin. Because, I am working 12 to 14 hour days on my day job, I just don't have time to thoroughly respond to all of the wrong-headed ideas you are presenting here, so I suggest you do the following "real world experiment": Since you hold Walt Maxwell in such high esteem (as do I), send him a synopsys of all your claims in this thread. I'd bet the ranch that he will take exception to much of what you are claiming, especially your notions of common-mode current and antenna resonance. Thanks for the spirited debate. Gotta go (work is calling). 73, Mike W4EF.........................
Reply to a comment by : W4LGH on 2007-02-27

KD2BD writes... "But, remember: This isn't about loss. :-) It's about a claim that a variable impedance matching device at the transmitter operates in a different manner depending on whether the antenna system is coax or open-wire fed, and that open-wire feed "becomes part of the antenna", whereas coax does not. Why the double-standard?" There is no double standard, it is 2 complely different feed systems. Open or balanced line has comsiderable less loss, its non-shielded so it can and does radiate. Simple proof test there too. Take a floursent bulb out and hold it next to the feed line , walk alone it and watch it light! Coax is shielded and technically does NOT radiate, you can have common mode currents ride the shield back into the shack, especially if your antenna is not resonant, but this energy is rarely if ever radiated, therefore it can NOT be tuned into the antenna system. The balanced feed line can and does radiate, so it can be effectively tuned into the antenna system. So there is no dual standard, its 2 completely different ways of getting your RF to the antenna. One works ok with acceptable trade off's, and the other one doesn't. 73 de W4LGH - Alan http://www.w4lgh.com And I am really done this time. This is getting way to old now.
Reply to a comment by : W4LGH on 2007-02-27

K9IUQ wrote~"Finally something we can agree on."~ Now thats damn scary! There is nothing magical about any antenna. If what you have works for you ,then so be it! All antennas are trade off's, even the resonant dipole, you trade off use on other bands. I have the luxury of having resonant dipoles for the major bands I work, my benchmarks so me more power being radiated, and higher receive signals. The losses were to great using a tuner inside for me.
Reply to a comment by : K9IUQ on 2007-02-27

W4LGH says: f you put something up, and it seems to work great, and you can talk to everyone you hear, this is NOT a BENCHMARK...as you don't know who you are NOT hearing. .................................................... Finally something we can agree on. When testing antennas you should always test a new antenna against a known well performing antenna. As one who has put up (and taken down) over a hundred different antennas in his lifetime, the well used term "I can work them if I can hear em " is NOT a benchmark. I have tested your valued resonant coax fed dipole against MANY other antennas in my lifetime. Contrary to what you believe I am not an idiot. Having tested and used over a hundred different antennas, resonant, non resonant and even your valued trap dipole, I can assure you the resonant coax dipole has NO magical properties over many other antennas with or without a tuner. If a resonant coax dipole was magical, better than other antennas, I would be using one. Alas it is not so, hence my present antenna farm looks much like Walter Maxwell's. Not because Walter said so BUT I did my own bencharks thru many years and proved to myself what works best. K9IUQ
K9IUQ2007-02-28
Benchmarks
W4LGH says: You have for sure proven you are the EXPERT with COPY/PASTE functions, hands down!

........................................................
Thanks AL!! Here is a little cut and paste for you, wanted to make sure you didnt miss it. It pretty well sums up your views......

>From KD2BD "you just can't reason with people who want to believe what they want to believe. Let the facts be dammed. The truth only causes them confusion by challenging their belief system -- something they keep VERY WELL protected through ignorance."

>And a direct quote from an earlier Post from K9IUQ:
"past experience has taught me people don't want to take the time to study the antenna literature and learn the truth. Trying to convince Hams like W4LGH that they are wrong is like trying to convince a Republican that a Democrat can govern better. It just isn't going to happen."

LMAO
Stan K9IUQ
KD2BD2007-02-28
RE: Benchmarks
K9IUQ wrote:

> The de-bunking of wifes tales continues. John I know
> you have written many articles, I wonder if you have
> written much about antennas? The reason I ask is you
> really have a knack for describing *in simple terms*
> how things work with antennas. Even I easily
> understand the concepts you have been writing about.

Thank you, Stan, for your kind words.

I remember writing an article on antennas a while back for "Satellite Times" magazine, but it concentrated on radiation patterns of dipoles used for Low Earth Orbiting satellite reception.

One concept I remember illustrating in that particular article is that an antenna perfectly matched to its transmission line, that's perfectly matched to a receiver's front end (1:1 VSWR), using lossless transmission line, is a system can achieve no more than 50% efficiency. :-O

Half the signal received by the antenna gets delivered to the receiver under these ideal conditions. The other half gets radiated back into space by the antennna.

And it's perfectly normal.

This is one of the properties behind the operation of 900 MHz RFID readers and transponders.

It is also the property behind the action of parasitic elements in a yagi.

Other than that, no antenna articles.

I once had a neighbor who accused me of interfering with this telephone. He even went to the extent of singling out the antenna that was causing him his grief. He explained to me that knew a thing or two about radio. He was a CBer.

In reality, the antenna he pointed out was an end-fed wire I used for general coverage HF RECEPTION! The far end of the wire was suspended by a tree -- something my knowledgeable neighbor informed me was illegal (because I was using it to transmit.) He was nice enough not to turn me in.

The biggest lesson I learned from that experience is that you just can't reason with people who want to believe what they want to believe. Let the facts be dammed. The truth only causes them confusion by challenging their belief system -- something they keep VERY WELL protected through ignorance.

The Earth is flat. Claims of it being otherwise are just a theory...

Sound familiar? :-)


73, de John, KD2BD
Reply to a comment by : K9IUQ on 2007-02-27

KD2BD says Sorry. None of that is true. Not even close. 73, de John KD2BD ...................................................... The de-bunking of wifes tales continues. John I know you have written many articles, I wonder if you have written much about antennas? The reason I ask is you really have a knack for describing *in simple terms* how things work with antennas. Even I easily understand the concepts you have been writing about. I have read much of Reflections by Walter Maxwell many times. It is an excellent book but I understand only about half of it. I always hunger for more factual information on antennas, and if you have written anything on the subject I want to read it. 73 Stan K9IUQ
W4LGH2007-02-28
RE: Benchmarks
John, KD2BD wrote..."It's not an issue of belief. It's not an issue of blind faith. What we're discussing isn't black magic, voodoo, or religion. Its Science."

Here we go with this perfect world again. They are THEORIES in Science/Physics! In physics, the term theory is generally used for a "mathematical framework", derived from a small set of basic principles (usually symmetries - like equality of locations in space or in time, or identity of electrons, etc), which is capable of producing experimental "predictions" for a given category of physical systems. A good example is electromagnetic theory, which encompasses the results that can be derived from gauge symmetry (sometimes called gauge invariance) in a form of a few equations called Maxwell's equations. Another name for this theory is classical electromagnetism. Note that the specific theoretical aspects of classical electromagnetic theory, which have been consistently and successfully replicated for well over a century, are termed "laws of electromagnetism", reflecting the fact that they are today "taken as granted". Within electromagnetic theory generally, there are numerous hypotheses about how electromagnetism applies to "specific situations". Many of these hypotheses are already considered to be adequately tested, with "new ones always in the making", and perhaps untested as yet.

So do what you want, take what has been said for the past 100 years for granted, or understand that the math does not fit every "specific situation" or go back to your perfect world, and totally believe that the "LAWS of ELECTROMAGNETISM" are and will always be the same for every application, without any chance of improvement.

Boy , where would we be today, if no one ever challenged previous theories and accepted things for the way they were. We'd still be in the dark ages!
Certainly wouldn't be any Ham radio, tv, internet...

Thank GOD for all those who dared to challenge and make improvements, and new developements, or we would be 100 years behind.

If you always do what you have always done, you will always get what you have always gotten. Now there's a fact for you!

This is getting old now, for there is a serious lack of imagination for without which, there can be no future!

73 de W4LGH - Alan
http://www.w4lgh.com


Reply to a comment by : KD2BD on 2007-02-28

W4EF wrote: > W4LGH wrote: >> >> walk alone it and watch it light! Coax is shielded >> and technically does NOT radiate, you can have >> common mode currents ride the shield back into the >> shack, especially if your antenna is not resonant, >> but this energy is rarely if ever radiated, >> therefore it can NOT be tuned into the antenna >> system. > > Alan, this just simply isn't true. By definition, > common-mode current flows on the outside of the coax > shield. It always causes radiation. And besides, > common-mode current is a red herring with regard to > this debate. Antenna feedpoint mismatch doesn't > automatically imply common mode feedline current. > You can have very high VSWR on both coax and > open-wire lines without having feeder current > imbalance (i.e. common-mode current). > > Your comments are so off base on all of this stuff, > I simply don't know where to begin. Agreed. Current flow on the outside of the coax's shield is NOT the result of an impedance mismatch at the feed point, or the antenna being off resonance. It is the result of feeding a balanced antenna with an unbalanced transmission line. When we feed a perfectly balanced dipole (and it doesn't even have to be resonant), and wish to maintain its balance, we feed each half with equal and opposite voltages and currents. (Differential feed.) If we could feed just one side of the dipole (with respect to ground) and see what happens in slow motion, we would see that as the RF voltage begins to rise in a positive direction on the left side of the dipole, an equal and opposite voltage will start to develop on the right. This is not unlike the way a child's seesaw operates. If we push down on one end, the other end moves up by an equal amount. We cannot push down or lift both ends at the same time with the same amount of force and expect the seesaw to move. A transmitter places the shield of its coaxial feed at the same potential as its chassis, close to what IT considers to be an RF ground. This potential is maintained all the way to the end of the feed line, IF it is terminated in an unbalanced load, regardless of the impedance. What happens when we feed a dipole with coax? Remember that neither side of the dipole's feed point is at RF ground potential. If, at one instant of time, we apply +70 volts through the inner conductor to the right side of the dipole, left side will respond by developing -70 volts. Connecting the coax shield directly to either side of the dipole places an RF voltage on the shield where none should exist. This improper feed arrangement causes imbalance in the antenna, radiation and current flow along the outside of the shield of the line, and could lead to "RF feedback" and "RF burn" situations in the shack. The good news is that a balun at the feed point will help alleviate the problem. However, unless the coax is brought down exactly perpendicular with respect to the dipole, it will tend to interact (slightly couple to) one side of the dipole more than the other, resulting in a slight imbalance of the antenna, and some RF current flow along the outside of the coax's shield below the point of the balun due to this coupling. What if we were to feed the dipole with balanced line? First of all, is the dipole perfectly balanced? (Are both halves under the EXACT same influence of the ground and other surrounding objects?) Probably not. Is the feedline run exactly perpendicular to the antenna (as was needed in the case with coax) and kept far away from influencing objects? If either one of these conditions are not fully met, then the antenna SYSTEM is not perfectly balanced, even though your balanced tuner is mistakingly assuming it is! I think the issues that affect balanced lines can be minimized somewhat by simply twisting the line, maybe one turn every couple of feet. This will tend to give each leg a fairly equal opportunity to couple into one side of the dipole or the other, minimizing any "bias" toward any one side. W4LGH wrote: > You guys do whatever you want to do, believe whatever > you want to believe. It's not an issue of belief. It's not an issue of blind faith. What we're discussing isn't black magic, voodoo, or religion. It's science. You can BELIEVE that open wire line "becomes part of the antenna" while coax does not, and that a variable impedance matching device connected to a coaxial transmission line does nothing more than "fool the transmitter"... But that simply does not make it a REALITY. 73, de John, KD2BD
Reply to a comment by : W4EF on 2007-02-27

W4LGH wrote: >> walk alone it and watch it light! Coax is shielded and technically does NOT radiate, you can have common mode currents ride the shield back into the shack, especially if your antenna is not resonant, but this energy is rarely if ever radiated, therefore it can NOT be tuned into the antenna system. << Alan, this just simply isn't true. By definition, common-mode current flows on the outside of the coax shield. It always causes radiation. And besides, common-mode current is a red herring with regard to this debate. Antenna feedpoint mismatch doesn't automatically imply common mode feedline current. You can have very high VSWR on both coax and open-wire lines without having feeder current imbalance (i.e. common-mode current). Your comments are so off base on all of this stuff, I simply don't know where to begin. Because, I am working 12 to 14 hour days on my day job, I just don't have time to thoroughly respond to all of the wrong-headed ideas you are presenting here, so I suggest you do the following "real world experiment": Since you hold Walt Maxwell in such high esteem (as do I), send him a synopsys of all your claims in this thread. I'd bet the ranch that he will take exception to much of what you are claiming, especially your notions of common-mode current and antenna resonance. Thanks for the spirited debate. Gotta go (work is calling). 73, Mike W4EF.........................
Reply to a comment by : W4LGH on 2007-02-27

KD2BD writes... "But, remember: This isn't about loss. :-) It's about a claim that a variable impedance matching device at the transmitter operates in a different manner depending on whether the antenna system is coax or open-wire fed, and that open-wire feed "becomes part of the antenna", whereas coax does not. Why the double-standard?" There is no double standard, it is 2 complely different feed systems. Open or balanced line has comsiderable less loss, its non-shielded so it can and does radiate. Simple proof test there too. Take a floursent bulb out and hold it next to the feed line , walk alone it and watch it light! Coax is shielded and technically does NOT radiate, you can have common mode currents ride the shield back into the shack, especially if your antenna is not resonant, but this energy is rarely if ever radiated, therefore it can NOT be tuned into the antenna system. The balanced feed line can and does radiate, so it can be effectively tuned into the antenna system. So there is no dual standard, its 2 completely different ways of getting your RF to the antenna. One works ok with acceptable trade off's, and the other one doesn't. 73 de W4LGH - Alan http://www.w4lgh.com And I am really done this time. This is getting way to old now.
Reply to a comment by : W4LGH on 2007-02-27

K9IUQ wrote~"Finally something we can agree on."~ Now thats damn scary! There is nothing magical about any antenna. If what you have works for you ,then so be it! All antennas are trade off's, even the resonant dipole, you trade off use on other bands. I have the luxury of having resonant dipoles for the major bands I work, my benchmarks so me more power being radiated, and higher receive signals. The losses were to great using a tuner inside for me.
Reply to a comment by : K9IUQ on 2007-02-27

W4LGH says: f you put something up, and it seems to work great, and you can talk to everyone you hear, this is NOT a BENCHMARK...as you don't know who you are NOT hearing. .................................................... Finally something we can agree on. When testing antennas you should always test a new antenna against a known well performing antenna. As one who has put up (and taken down) over a hundred different antennas in his lifetime, the well used term "I can work them if I can hear em " is NOT a benchmark. I have tested your valued resonant coax fed dipole against MANY other antennas in my lifetime. Contrary to what you believe I am not an idiot. Having tested and used over a hundred different antennas, resonant, non resonant and even your valued trap dipole, I can assure you the resonant coax dipole has NO magical properties over many other antennas with or without a tuner. If a resonant coax dipole was magical, better than other antennas, I would be using one. Alas it is not so, hence my present antenna farm looks much like Walter Maxwell's. Not because Walter said so BUT I did my own bencharks thru many years and proved to myself what works best. K9IUQ
K9IUQ2007-02-28
Benchmarks
W4LGH continues with nonsense:And for a 3 element StepIR to go head to head with your LOG, and its many elements says a LOT for the StepIR! Wonder why that is? RESONANCE...hahahahahahahahahahahahaha

.....................................................
Al your lack of antenna knowledge knows NO bounds.

My Log Periodic Antenna is resonance and if it were not my tuner WOULD resonate it. Mine has 6 elements and not ALL the elements are in use at a given band. Have you NOT read ANY antenna books?

I wonder how long you have been a ham AL? You have a vanity call. Are you a Newbie ham, you certainly act like one...

Shaking his head,
Stan (47 years hamming) K9IUQ - Non Vanity Call
KD2BD2007-02-28
RE: Benchmarks
W4EF wrote:

> W4LGH wrote:
>>
>> walk alone it and watch it light! Coax is shielded
>> and technically does NOT radiate, you can have
>> common mode currents ride the shield back into the
>> shack, especially if your antenna is not resonant,
>> but this energy is rarely if ever radiated,
>> therefore it can NOT be tuned into the antenna
>> system.
>
> Alan, this just simply isn't true. By definition,
> common-mode current flows on the outside of the coax
> shield. It always causes radiation. And besides,
> common-mode current is a red herring with regard to
> this debate. Antenna feedpoint mismatch doesn't
> automatically imply common mode feedline current.
> You can have very high VSWR on both coax and
> open-wire lines without having feeder current
> imbalance (i.e. common-mode current).
>
> Your comments are so off base on all of this stuff,
> I simply don't know where to begin.

Agreed.

Current flow on the outside of the coax's shield is NOT the result of an impedance mismatch at the feed point, or the antenna being off resonance. It is the result of feeding a balanced antenna with an unbalanced transmission line.

When we feed a perfectly balanced dipole (and it doesn't even have to be resonant), and wish to maintain its balance, we feed each half with equal and opposite voltages and currents. (Differential feed.)

If we could feed just one side of the dipole (with respect to ground) and see what happens in slow motion, we would see that as the RF voltage begins to rise in a positive direction on the left side of the dipole, an equal and opposite voltage will start to develop on the right.

This is not unlike the way a child's seesaw operates. If we push down on one end, the other end moves up by an equal amount. We cannot push down or lift both ends at the same time with the same amount of force and expect the seesaw to move.

A transmitter places the shield of its coaxial feed at the same potential as its chassis, close to what IT considers to be an RF ground. This potential is maintained all the way to the end of the feed line, IF it is terminated in an unbalanced load, regardless of the impedance.

What happens when we feed a dipole with coax?

Remember that neither side of the dipole's feed point is at RF ground potential. If, at one instant of time, we apply +70 volts through the inner conductor to the right side of the dipole, left side will respond by developing -70 volts.

Connecting the coax shield directly to either side of the dipole places an RF voltage on the shield where none should exist.

This improper feed arrangement causes imbalance in the antenna, radiation and current flow along the outside of the shield of the line, and could lead to "RF feedback" and "RF burn" situations in the shack.

The good news is that a balun at the feed point will help alleviate the problem.

However, unless the coax is brought down exactly perpendicular with respect to the dipole, it will tend to interact (slightly couple to) one side of the dipole more than the other, resulting in a slight imbalance of the antenna, and some RF current flow along the outside of the coax's shield below the point of the balun due to this coupling.

What if we were to feed the dipole with balanced line?

First of all, is the dipole perfectly balanced? (Are both halves under the EXACT same influence of the ground and other surrounding objects?) Probably not.

Is the feedline run exactly perpendicular to the antenna (as was needed in the case with coax) and kept far away from influencing objects?

If either one of these conditions are not fully met, then the antenna SYSTEM is not perfectly balanced, even though your balanced tuner is mistakingly assuming it is!

I think the issues that affect balanced lines can be minimized somewhat by simply twisting the line, maybe one turn every couple of feet. This will tend to give each leg a fairly equal opportunity to couple into one side of the dipole or the other, minimizing any "bias" toward any one side.

W4LGH wrote:

> You guys do whatever you want to do, believe whatever
> you want to believe.

It's not an issue of belief. It's not an issue of blind faith. What we're discussing isn't black magic, voodoo, or religion.

It's science.

You can BELIEVE that open wire line "becomes part of the antenna" while coax does not, and that a variable impedance matching device connected to a coaxial transmission line does nothing more than "fool the transmitter"...

But that simply does not make it a REALITY.


73, de John, KD2BD
Reply to a comment by : W4EF on 2007-02-27

W4LGH wrote: >> walk alone it and watch it light! Coax is shielded and technically does NOT radiate, you can have common mode currents ride the shield back into the shack, especially if your antenna is not resonant, but this energy is rarely if ever radiated, therefore it can NOT be tuned into the antenna system. << Alan, this just simply isn't true. By definition, common-mode current flows on the outside of the coax shield. It always causes radiation. And besides, common-mode current is a red herring with regard to this debate. Antenna feedpoint mismatch doesn't automatically imply common mode feedline current. You can have very high VSWR on both coax and open-wire lines without having feeder current imbalance (i.e. common-mode current). Your comments are so off base on all of this stuff, I simply don't know where to begin. Because, I am working 12 to 14 hour days on my day job, I just don't have time to thoroughly respond to all of the wrong-headed ideas you are presenting here, so I suggest you do the following "real world experiment": Since you hold Walt Maxwell in such high esteem (as do I), send him a synopsys of all your claims in this thread. I'd bet the ranch that he will take exception to much of what you are claiming, especially your notions of common-mode current and antenna resonance. Thanks for the spirited debate. Gotta go (work is calling). 73, Mike W4EF.........................
Reply to a comment by : W4LGH on 2007-02-27

KD2BD writes... "But, remember: This isn't about loss. :-) It's about a claim that a variable impedance matching device at the transmitter operates in a different manner depending on whether the antenna system is coax or open-wire fed, and that open-wire feed "becomes part of the antenna", whereas coax does not. Why the double-standard?" There is no double standard, it is 2 complely different feed systems. Open or balanced line has comsiderable less loss, its non-shielded so it can and does radiate. Simple proof test there too. Take a floursent bulb out and hold it next to the feed line , walk alone it and watch it light! Coax is shielded and technically does NOT radiate, you can have common mode currents ride the shield back into the shack, especially if your antenna is not resonant, but this energy is rarely if ever radiated, therefore it can NOT be tuned into the antenna system. The balanced feed line can and does radiate, so it can be effectively tuned into the antenna system. So there is no dual standard, its 2 completely different ways of getting your RF to the antenna. One works ok with acceptable trade off's, and the other one doesn't. 73 de W4LGH - Alan http://www.w4lgh.com And I am really done this time. This is getting way to old now.
Reply to a comment by : W4LGH on 2007-02-27

K9IUQ wrote~"Finally something we can agree on."~ Now thats damn scary! There is nothing magical about any antenna. If what you have works for you ,then so be it! All antennas are trade off's, even the resonant dipole, you trade off use on other bands. I have the luxury of having resonant dipoles for the major bands I work, my benchmarks so me more power being radiated, and higher receive signals. The losses were to great using a tuner inside for me.
Reply to a comment by : K9IUQ on 2007-02-27

W4LGH says: f you put something up, and it seems to work great, and you can talk to everyone you hear, this is NOT a BENCHMARK...as you don't know who you are NOT hearing. .................................................... Finally something we can agree on. When testing antennas you should always test a new antenna against a known well performing antenna. As one who has put up (and taken down) over a hundred different antennas in his lifetime, the well used term "I can work them if I can hear em " is NOT a benchmark. I have tested your valued resonant coax fed dipole against MANY other antennas in my lifetime. Contrary to what you believe I am not an idiot. Having tested and used over a hundred different antennas, resonant, non resonant and even your valued trap dipole, I can assure you the resonant coax dipole has NO magical properties over many other antennas with or without a tuner. If a resonant coax dipole was magical, better than other antennas, I would be using one. Alas it is not so, hence my present antenna farm looks much like Walter Maxwell's. Not because Walter said so BUT I did my own bencharks thru many years and proved to myself what works best. K9IUQ
W4LGH2007-02-28
RE: Benchmarks
Your Ham friend..Stan K9IUQ wrote..."I can understand why you dont like me Al. I , along with a LOT of help from you and many other very smart hams have shown your views to be untruths,and BS, sprinkled with old wifes tales."~~~

I knew we wouldn't be that lucky. Just like a bad penny..oh well...Stan you and several others on here are just way to smart for me. Yall know it all, have done it all, and have answers for everything. Read all the right books, and worked the proper math, and above all, live in this perfect world.

No sir, way out of my class. I have to roll my sleeves up and get down and dirty and do actual performance tests and real time compairsons to get my proofs. The math is a great place to get a starting point, but when you leave that perfect world, the theories (non-proven truths) just don't seem to work the same. Your .1db losses soon become 10db losses.

Nope, I just can't seem to get into this perfect world, its always out of my reach. And for a 3 element StepIR to go head to head with your LOG, and its many elements says a LOT for the StepIR! Wonder why that is? RESONANCE...hahahahahahahahahahahahaha

Good nite Stan! I can't wait to hear what you have to say, or copy next! You have for sure proven you are the EXPERT with COPY/PASTE functions, hands down!

73 de W4LGH - Alan

Reply to a comment by : K9IUQ on 2007-02-28

W4LGH says Ok, where's Stan??? I can't wait to hear what he has to say next?? He's a PLATHERA of information! Maybe he did sell his junk off, took down his non-rez loop? Nawwwwww...we wouldn't be that lucky! ..................................................... I can understand why you dont like me Al. I , along with a LOT of help from you and many other very smart hams have shown your views to be untruths,and BS, sprinkled with old wifes tales. You have done a real service for many Hams Al. I have had much fun with you. You have made me laugh harder than I have in years. I dont dislike you Al. You are just another ham , misguided perhaps.Since we both like some of the same things- Vintage Ham Gear for instance, we probably would enjoy talking to each other on the air - provided you didnt mention antennas. Your Ham friend Stan K9IUQ
W4LGH2007-02-28
RE: Benchmarks
Don't go to cheap on your wire. A good 12gauge wire is hard to beat and will with stand a lot of abuse.
Smaller wires will break very easy. Also Lowe's sells a black bungee cord that is 4' long un-stretched, and will stretch out to 10'. Use 2 of these on the ends of your wires if in trees, and it will keep the antenna tight, but allow for tree sway. My wires went thru the the 4 hurricanes we had a couple years back.
We had 70mph winds with gusts to 90mph. Proof enough for me.

Another idea for your auto antenna is to use 2 self winding 100' measuring tapes, then use only 2 winding spools with black dacron rope to pull it out, rev the motor and the tapes will wind back in. If you worked it out right, you could use just one winding spool.

73 de W4LGH Alan
Reply to a comment by : KC8QFP on 2007-02-28

PS: I wanted to mention that some guys on hfpack/yahoo groups were talking about good places to get cheap wire for antennaes. One looks pretty good to me, the wire used for INVISIBLE FENCE to keep the mutt in the yard. I think they said it is about $40.00 for a spool of 500 feet of the stuff. Don
Reply to a comment by : KC8QFP on 2007-02-28

I've had bad luck with numbers for a long time. It didn't take me long to figure out that the specs you see in the rag sheets almost never work right. When I first got my ticket, I got the ARRL handbook, subscribed to QST, 73 and CQ, and also read a lotta books at the library when I endevered on various projects. The last debacle was an antenna that I saw in an artical, perhaps in 73, about some sort of folded back multiband dipole (I forget the author's name for it). I was maticulous about the measurements and following his directions. It was a rather short and sweet artical, so I did not have much to go on, but it was adequite. I did do as suggested, with the formulas, to tune it for the portions of the bands I wanted to use. When I got it up, it was fine for 80m, and needed a trim for 40m, but the rest of the bands were WAY OFF! All that extra wire and trouble amounted to a two-bander, and narrow bandwidth at that. The sun UV and wind blew all the taped cable-ties apart, so it ended up with wires dangling all over the place. (I used the black cable ties too, although cheapie ones). After all the troubles I had with it, I decided to go with KISS. When the weather breaks, I plan to trim off all that wire, and make it a single wire inverted VEE, but also want something better, and may just start all over again. All this explanation to say why I do not have a lotta confidence in the paper BS. 73, Don
Reply to a comment by : KC8QFP on 2007-02-28

I've never seen the Steppir in action. I thought they were Yagi's, but I really don't know much about them. I also was under the impression that they are very $$$, the sky's the limit for many hams, but I am cost conscientious. My little idea can be made CHEAPly. I cannot afford beams, and again I feel the little bit of gain you get for a beam is lost in cost. I like beams and verticals for the VHF and above crowd. And I go with the quad over the Yagi, I have a four el home brew (quad quad) for 2m that works great. Anyhow, I'm am not anti-vertical, but it is difficult to get the length for lower than 40m on a vertical. Wires are easy and cheap. I was going to try two antennaes for 80/40m. (I don't have 160, may consider that some day). I like either mono-bander, offset feed dipoles or inverted vees. Another variation would be a loop. But the antenna that has my attention now and one that I have not tried yet is the HALF SQUARE. That seems to be the better choice for 40m to me. I'll probably keep the Hustler for the higher freqs. I have a dipole for 80, but it tunes for the lower sec of 80m. I want something a little more broad banded with good capture, perhaps a delta loop? Just tossin' ideas about here, that what the facts and figures are all about. Numbers are nice on paper, but real world tends to mess with the numbers, so many variables. I've learned that it is sort of a give and take situation, to get somethings, you usually have to sacrifice something else, i.e. broadband usually means less gain. But I think the Steppir is more like a Cadillac, and I have a Yugo budget! Cheerz, Don
Reply to a comment by : K9IUQ on 2007-02-28

Kc8QFP says Howz about ONE tunable antenna? One antenna that you can change its length. .................................................. Can you spell Steppir? They havent done it with a horizontal dipole yet but they do make a vertical that changes length. I have been the Vertical antenna route many times in my ham career. Have had a Hustler, hygain, Butternut and a couple different Gaps. Most of them never worked as well as my 130ft centerfed with open feedline (with ABSURD antenna tuner). Seems to me at one time I saw a commercial changeable length dipole for sale. You had to change the length manually though which would be a major pain. "One good working antenna that does it all! A Ham's dream come true!" K9IUQ says There are many to pick from, but a resonant dipole is not among of them.... K9IUQ
Reply to a comment by : KC8QFP on 2007-02-28

<<<<< Now can someone tell me how I am going to put 5 reasonant dipoles on only a 1 acre lot?? I dont want no trap dipole or fan dipole either. How do you guys do it if you just have a 50 x 100 ft city lot? There MUST be a trick here I am mising. HELP I wannna throw out that damn ABSURD tuner. Where is W4LGH when you need him? Stan K9IUQ >>>>> Howz about ONE tunable antenna? One antenna that you can change its length. I have a much smaller yard than you, and presently have the Hustler 5BTV which is worthless on 80m. So I have a dipole for that. I tried to tune it for mid band, and my transmitter can handle 3:1. I was going to go with the GAP since it seems so many hams are vertical these days. But I am working on an idea to make a tunable antenna. Counter weights hanging from pulleys at the ends will compensate for the various lengths (but you must have enough height). I got that idea from the counter weights on my windows. The real tricky part would be the feedpoint, a couple of spools (as in a fishing reel) to mechanically adjust the antenna length. A slow RPM motor (I have an old electric screwdriver for that part) would rotate the spools either way (in or out). I was thinking of using BARE wire and metal spools, so as to shunt the coils created by the spools. It may need a cap to nix the impedance bump at the feedpoint, but I think it can work. Of course there must be a contact surface (perhaps brushes) for moving electrical connections. I suppose that it's been tried and true (or not true)? Usually things like this idea needs the kinks worked out, but this is a way to do it with ONE antenna. I bet the SWL's would buy it! The antenna would be the variable inverted VEE or VIV. I am a simple guy (KISS), so you guys with all the brains take it from here. One good working antenna that does it all! A Ham's dream come true! 73, Don
Reply to a comment by : K9IUQ on 2007-02-28

Practical Considerations and the Radio Amateur Ok I give up. W4LGH is right, everyone else is wrong. I am going to take down my 130ft centerfed antenna with open feeders (and a ABSURD antenna tuner)that I use for 75,60,40,30 mtrs. And put up REASONANT coax fed dipoles for each band. But wait I know from past experience a dipole won't cover the whole 75 mtr band. I want to to talk to my buddies on the high end of 75 AND pound brass on 3515. So I will need 2 antennas for 75mtr because no way am I going to use the ABSURD antenna tuner and give up half my signal. I surveyed my lot this morning. I have 1 1/2 acre but 1/2 acre is in woods and unsuitable for antennas. I also have a large metal pole barn, which I know will not help my antennas , so I have to stay away from that. Also my powerline is overhead coming in the front of the house. Gotta stay away from that too, plus my xyl doesn't want ANY antenna in the front yard.Also I have a tower with a Log Peridioc beam, I dont want to miss up my dx on 20 mtrs so I have to stay away from that too. Now can someone tell me how I am going to put 5 reasonant dipoles on only a 1 acre lot?? I dont want no trap dipole or fan dipole either. How do you guys do it if you just have a 50 x 100 ft city lot? There MUST be a trick here I am mising. HELP I wannna throw out that damn ABSURD tuner. Where is W4LGH when you need him? Stan K9IUQ
K9IUQ2007-02-28
Benchmarks
W4LGH says Ok, where's Stan??? I can't wait to hear what he has to say next?? He's a PLATHERA of information! Maybe he did sell his junk off, took down his non-rez loop?

Nawwwwww...we wouldn't be that lucky!

.....................................................
I can understand why you dont like me Al. I , along with a LOT of help from you and many other very smart hams have shown your views to be untruths,and BS, sprinkled with old wifes tales. You have done a real service for many Hams Al. I have had much fun with you. You have made me laugh harder than I have in years.

I dont dislike you Al. You are just another ham , misguided perhaps.Since we both like some of the same things- Vintage Ham Gear for instance, we probably would enjoy talking to each other on the air - provided you didnt mention antennas.

Your Ham friend
Stan K9IUQ


K9IUQ2007-02-28
RE: Benchmarks
KC8QFB says I've never seen the Steppir in action. I thought they were Yagi's, but I really don't know much about them. I also was under the impression that they are very $$$,
.......................................................
They are very $$$ figure about $1600 for a 3 element yagi . I have a friend that has one here locally. They are nice antennas. there is nothing magical about them. Performance wise, My Log is the equal of his Steppir, we have tested both head to head.

Steppir also makes a couple of Vertical antennas, same idea as their yagis.

>>Kc8QFB says I cannot afford beams, and again I feel the little bit of gain you get for a beam is lost in cost.>>>>

NOT TRUE. You just dont know how much you are missing until you get a beam. Even a small Beam like a Cushcraft
Ma5B will be a tremendous improvement over a non-gain antenna.

Stan K9IUQ



Reply to a comment by : KC8QFP on 2007-02-28

I've never seen the Steppir in action. I thought they were Yagi's, but I really don't know much about them. I also was under the impression that they are very $$$, the sky's the limit for many hams, but I am cost conscientious. My little idea can be made CHEAPly. I cannot afford beams, and again I feel the little bit of gain you get for a beam is lost in cost. I like beams and verticals for the VHF and above crowd. And I go with the quad over the Yagi, I have a four el home brew (quad quad) for 2m that works great. Anyhow, I'm am not anti-vertical, but it is difficult to get the length for lower than 40m on a vertical. Wires are easy and cheap. I was going to try two antennaes for 80/40m. (I don't have 160, may consider that some day). I like either mono-bander, offset feed dipoles or inverted vees. Another variation would be a loop. But the antenna that has my attention now and one that I have not tried yet is the HALF SQUARE. That seems to be the better choice for 40m to me. I'll probably keep the Hustler for the higher freqs. I have a dipole for 80, but it tunes for the lower sec of 80m. I want something a little more broad banded with good capture, perhaps a delta loop? Just tossin' ideas about here, that what the facts and figures are all about. Numbers are nice on paper, but real world tends to mess with the numbers, so many variables. I've learned that it is sort of a give and take situation, to get somethings, you usually have to sacrifice something else, i.e. broadband usually means less gain. But I think the Steppir is more like a Cadillac, and I have a Yugo budget! Cheerz, Don
Reply to a comment by : K9IUQ on 2007-02-28

Kc8QFP says Howz about ONE tunable antenna? One antenna that you can change its length. .................................................. Can you spell Steppir? They havent done it with a horizontal dipole yet but they do make a vertical that changes length. I have been the Vertical antenna route many times in my ham career. Have had a Hustler, hygain, Butternut and a couple different Gaps. Most of them never worked as well as my 130ft centerfed with open feedline (with ABSURD antenna tuner). Seems to me at one time I saw a commercial changeable length dipole for sale. You had to change the length manually though which would be a major pain. "One good working antenna that does it all! A Ham's dream come true!" K9IUQ says There are many to pick from, but a resonant dipole is not among of them.... K9IUQ
Reply to a comment by : KC8QFP on 2007-02-28

<<<<< Now can someone tell me how I am going to put 5 reasonant dipoles on only a 1 acre lot?? I dont want no trap dipole or fan dipole either. How do you guys do it if you just have a 50 x 100 ft city lot? There MUST be a trick here I am mising. HELP I wannna throw out that damn ABSURD tuner. Where is W4LGH when you need him? Stan K9IUQ >>>>> Howz about ONE tunable antenna? One antenna that you can change its length. I have a much smaller yard than you, and presently have the Hustler 5BTV which is worthless on 80m. So I have a dipole for that. I tried to tune it for mid band, and my transmitter can handle 3:1. I was going to go with the GAP since it seems so many hams are vertical these days. But I am working on an idea to make a tunable antenna. Counter weights hanging from pulleys at the ends will compensate for the various lengths (but you must have enough height). I got that idea from the counter weights on my windows. The real tricky part would be the feedpoint, a couple of spools (as in a fishing reel) to mechanically adjust the antenna length. A slow RPM motor (I have an old electric screwdriver for that part) would rotate the spools either way (in or out). I was thinking of using BARE wire and metal spools, so as to shunt the coils created by the spools. It may need a cap to nix the impedance bump at the feedpoint, but I think it can work. Of course there must be a contact surface (perhaps brushes) for moving electrical connections. I suppose that it's been tried and true (or not true)? Usually things like this idea needs the kinks worked out, but this is a way to do it with ONE antenna. I bet the SWL's would buy it! The antenna would be the variable inverted VEE or VIV. I am a simple guy (KISS), so you guys with all the brains take it from here. One good working antenna that does it all! A Ham's dream come true! 73, Don
Reply to a comment by : K9IUQ on 2007-02-28

Practical Considerations and the Radio Amateur Ok I give up. W4LGH is right, everyone else is wrong. I am going to take down my 130ft centerfed antenna with open feeders (and a ABSURD antenna tuner)that I use for 75,60,40,30 mtrs. And put up REASONANT coax fed dipoles for each band. But wait I know from past experience a dipole won't cover the whole 75 mtr band. I want to to talk to my buddies on the high end of 75 AND pound brass on 3515. So I will need 2 antennas for 75mtr because no way am I going to use the ABSURD antenna tuner and give up half my signal. I surveyed my lot this morning. I have 1 1/2 acre but 1/2 acre is in woods and unsuitable for antennas. I also have a large metal pole barn, which I know will not help my antennas , so I have to stay away from that. Also my powerline is overhead coming in the front of the house. Gotta stay away from that too, plus my xyl doesn't want ANY antenna in the front yard.Also I have a tower with a Log Peridioc beam, I dont want to miss up my dx on 20 mtrs so I have to stay away from that too. Now can someone tell me how I am going to put 5 reasonant dipoles on only a 1 acre lot?? I dont want no trap dipole or fan dipole either. How do you guys do it if you just have a 50 x 100 ft city lot? There MUST be a trick here I am mising. HELP I wannna throw out that damn ABSURD tuner. Where is W4LGH when you need him? Stan K9IUQ
KC8QFP2007-02-28
RE: Benchmarks
PS: I wanted to mention that some guys on hfpack/yahoo groups were talking about good places to get cheap wire for antennaes. One looks pretty good to me, the wire used for INVISIBLE FENCE to keep the mutt in the yard. I think they said it is about $40.00 for a spool of 500 feet of the stuff.

Don
Reply to a comment by : KC8QFP on 2007-02-28

I've had bad luck with numbers for a long time. It didn't take me long to figure out that the specs you see in the rag sheets almost never work right. When I first got my ticket, I got the ARRL handbook, subscribed to QST, 73 and CQ, and also read a lotta books at the library when I endevered on various projects. The last debacle was an antenna that I saw in an artical, perhaps in 73, about some sort of folded back multiband dipole (I forget the author's name for it). I was maticulous about the measurements and following his directions. It was a rather short and sweet artical, so I did not have much to go on, but it was adequite. I did do as suggested, with the formulas, to tune it for the portions of the bands I wanted to use. When I got it up, it was fine for 80m, and needed a trim for 40m, but the rest of the bands were WAY OFF! All that extra wire and trouble amounted to a two-bander, and narrow bandwidth at that. The sun UV and wind blew all the taped cable-ties apart, so it ended up with wires dangling all over the place. (I used the black cable ties too, although cheapie ones). After all the troubles I had with it, I decided to go with KISS. When the weather breaks, I plan to trim off all that wire, and make it a single wire inverted VEE, but also want something better, and may just start all over again. All this explanation to say why I do not have a lotta confidence in the paper BS. 73, Don
Reply to a comment by : KC8QFP on 2007-02-28

I've never seen the Steppir in action. I thought they were Yagi's, but I really don't know much about them. I also was under the impression that they are very $$$, the sky's the limit for many hams, but I am cost conscientious. My little idea can be made CHEAPly. I cannot afford beams, and again I feel the little bit of gain you get for a beam is lost in cost. I like beams and verticals for the VHF and above crowd. And I go with the quad over the Yagi, I have a four el home brew (quad quad) for 2m that works great. Anyhow, I'm am not anti-vertical, but it is difficult to get the length for lower than 40m on a vertical. Wires are easy and cheap. I was going to try two antennaes for 80/40m. (I don't have 160, may consider that some day). I like either mono-bander, offset feed dipoles or inverted vees. Another variation would be a loop. But the antenna that has my attention now and one that I have not tried yet is the HALF SQUARE. That seems to be the better choice for 40m to me. I'll probably keep the Hustler for the higher freqs. I have a dipole for 80, but it tunes for the lower sec of 80m. I want something a little more broad banded with good capture, perhaps a delta loop? Just tossin' ideas about here, that what the facts and figures are all about. Numbers are nice on paper, but real world tends to mess with the numbers, so many variables. I've learned that it is sort of a give and take situation, to get somethings, you usually have to sacrifice something else, i.e. broadband usually means less gain. But I think the Steppir is more like a Cadillac, and I have a Yugo budget! Cheerz, Don
Reply to a comment by : K9IUQ on 2007-02-28

Kc8QFP says Howz about ONE tunable antenna? One antenna that you can change its length. .................................................. Can you spell Steppir? They havent done it with a horizontal dipole yet but they do make a vertical that changes length. I have been the Vertical antenna route many times in my ham career. Have had a Hustler, hygain, Butternut and a couple different Gaps. Most of them never worked as well as my 130ft centerfed with open feedline (with ABSURD antenna tuner). Seems to me at one time I saw a commercial changeable length dipole for sale. You had to change the length manually though which would be a major pain. "One good working antenna that does it all! A Ham's dream come true!" K9IUQ says There are many to pick from, but a resonant dipole is not among of them.... K9IUQ
Reply to a comment by : KC8QFP on 2007-02-28

<<<<< Now can someone tell me how I am going to put 5 reasonant dipoles on only a 1 acre lot?? I dont want no trap dipole or fan dipole either. How do you guys do it if you just have a 50 x 100 ft city lot? There MUST be a trick here I am mising. HELP I wannna throw out that damn ABSURD tuner. Where is W4LGH when you need him? Stan K9IUQ >>>>> Howz about ONE tunable antenna? One antenna that you can change its length. I have a much smaller yard than you, and presently have the Hustler 5BTV which is worthless on 80m. So I have a dipole for that. I tried to tune it for mid band, and my transmitter can handle 3:1. I was going to go with the GAP since it seems so many hams are vertical these days. But I am working on an idea to make a tunable antenna. Counter weights hanging from pulleys at the ends will compensate for the various lengths (but you must have enough height). I got that idea from the counter weights on my windows. The real tricky part would be the feedpoint, a couple of spools (as in a fishing reel) to mechanically adjust the antenna length. A slow RPM motor (I have an old electric screwdriver for that part) would rotate the spools either way (in or out). I was thinking of using BARE wire and metal spools, so as to shunt the coils created by the spools. It may need a cap to nix the impedance bump at the feedpoint, but I think it can work. Of course there must be a contact surface (perhaps brushes) for moving electrical connections. I suppose that it's been tried and true (or not true)? Usually things like this idea needs the kinks worked out, but this is a way to do it with ONE antenna. I bet the SWL's would buy it! The antenna would be the variable inverted VEE or VIV. I am a simple guy (KISS), so you guys with all the brains take it from here. One good working antenna that does it all! A Ham's dream come true! 73, Don
Reply to a comment by : K9IUQ on 2007-02-28

Practical Considerations and the Radio Amateur Ok I give up. W4LGH is right, everyone else is wrong. I am going to take down my 130ft centerfed antenna with open feeders (and a ABSURD antenna tuner)that I use for 75,60,40,30 mtrs. And put up REASONANT coax fed dipoles for each band. But wait I know from past experience a dipole won't cover the whole 75 mtr band. I want to to talk to my buddies on the high end of 75 AND pound brass on 3515. So I will need 2 antennas for 75mtr because no way am I going to use the ABSURD antenna tuner and give up half my signal. I surveyed my lot this morning. I have 1 1/2 acre but 1/2 acre is in woods and unsuitable for antennas. I also have a large metal pole barn, which I know will not help my antennas , so I have to stay away from that. Also my powerline is overhead coming in the front of the house. Gotta stay away from that too, plus my xyl doesn't want ANY antenna in the front yard.Also I have a tower with a Log Peridioc beam, I dont want to miss up my dx on 20 mtrs so I have to stay away from that too. Now can someone tell me how I am going to put 5 reasonant dipoles on only a 1 acre lot?? I dont want no trap dipole or fan dipole either. How do you guys do it if you just have a 50 x 100 ft city lot? There MUST be a trick here I am mising. HELP I wannna throw out that damn ABSURD tuner. Where is W4LGH when you need him? Stan K9IUQ
KC8QFP2007-02-28
RE: Benchmarks
I've had bad luck with numbers for a long time. It didn't take me long to figure out that the specs you see in the rag sheets almost never work right. When I first got my ticket, I got the ARRL handbook, subscribed to QST, 73 and CQ, and also read a lotta books at the library when I endevered on various projects. The last debacle was an antenna that I saw in an artical, perhaps in 73, about some sort of folded back multiband dipole (I forget the author's name for it). I was maticulous about the measurements and following his directions. It was a rather short and sweet artical, so I did not have much to go on, but it was adequite. I did do as suggested, with the formulas, to tune it for the portions of the bands I wanted to use. When I got it up, it was fine for 80m, and needed a trim for 40m, but the rest of the bands were WAY OFF! All that extra wire and trouble amounted to a two-bander, and narrow bandwidth at that. The sun UV and wind blew all the taped cable-ties apart, so it ended up with wires dangling all over the place. (I used the black cable ties too, although cheapie ones). After all the troubles I had with it, I decided to go with KISS. When the weather breaks, I plan to trim off all that wire, and make it a single wire inverted VEE, but also want something better, and may just start all over again. All this explanation to say why I do not have a lotta confidence in the paper BS.

73, Don
Reply to a comment by : KC8QFP on 2007-02-28

I've never seen the Steppir in action. I thought they were Yagi's, but I really don't know much about them. I also was under the impression that they are very $$$, the sky's the limit for many hams, but I am cost conscientious. My little idea can be made CHEAPly. I cannot afford beams, and again I feel the little bit of gain you get for a beam is lost in cost. I like beams and verticals for the VHF and above crowd. And I go with the quad over the Yagi, I have a four el home brew (quad quad) for 2m that works great. Anyhow, I'm am not anti-vertical, but it is difficult to get the length for lower than 40m on a vertical. Wires are easy and cheap. I was going to try two antennaes for 80/40m. (I don't have 160, may consider that some day). I like either mono-bander, offset feed dipoles or inverted vees. Another variation would be a loop. But the antenna that has my attention now and one that I have not tried yet is the HALF SQUARE. That seems to be the better choice for 40m to me. I'll probably keep the Hustler for the higher freqs. I have a dipole for 80, but it tunes for the lower sec of 80m. I want something a little more broad banded with good capture, perhaps a delta loop? Just tossin' ideas about here, that what the facts and figures are all about. Numbers are nice on paper, but real world tends to mess with the numbers, so many variables. I've learned that it is sort of a give and take situation, to get somethings, you usually have to sacrifice something else, i.e. broadband usually means less gain. But I think the Steppir is more like a Cadillac, and I have a Yugo budget! Cheerz, Don
Reply to a comment by : K9IUQ on 2007-02-28

Kc8QFP says Howz about ONE tunable antenna? One antenna that you can change its length. .................................................. Can you spell Steppir? They havent done it with a horizontal dipole yet but they do make a vertical that changes length. I have been the Vertical antenna route many times in my ham career. Have had a Hustler, hygain, Butternut and a couple different Gaps. Most of them never worked as well as my 130ft centerfed with open feedline (with ABSURD antenna tuner). Seems to me at one time I saw a commercial changeable length dipole for sale. You had to change the length manually though which would be a major pain. "One good working antenna that does it all! A Ham's dream come true!" K9IUQ says There are many to pick from, but a resonant dipole is not among of them.... K9IUQ
Reply to a comment by : KC8QFP on 2007-02-28

<<<<< Now can someone tell me how I am going to put 5 reasonant dipoles on only a 1 acre lot?? I dont want no trap dipole or fan dipole either. How do you guys do it if you just have a 50 x 100 ft city lot? There MUST be a trick here I am mising. HELP I wannna throw out that damn ABSURD tuner. Where is W4LGH when you need him? Stan K9IUQ >>>>> Howz about ONE tunable antenna? One antenna that you can change its length. I have a much smaller yard than you, and presently have the Hustler 5BTV which is worthless on 80m. So I have a dipole for that. I tried to tune it for mid band, and my transmitter can handle 3:1. I was going to go with the GAP since it seems so many hams are vertical these days. But I am working on an idea to make a tunable antenna. Counter weights hanging from pulleys at the ends will compensate for the various lengths (but you must have enough height). I got that idea from the counter weights on my windows. The real tricky part would be the feedpoint, a couple of spools (as in a fishing reel) to mechanically adjust the antenna length. A slow RPM motor (I have an old electric screwdriver for that part) would rotate the spools either way (in or out). I was thinking of using BARE wire and metal spools, so as to shunt the coils created by the spools. It may need a cap to nix the impedance bump at the feedpoint, but I think it can work. Of course there must be a contact surface (perhaps brushes) for moving electrical connections. I suppose that it's been tried and true (or not true)? Usually things like this idea needs the kinks worked out, but this is a way to do it with ONE antenna. I bet the SWL's would buy it! The antenna would be the variable inverted VEE or VIV. I am a simple guy (KISS), so you guys with all the brains take it from here. One good working antenna that does it all! A Ham's dream come true! 73, Don
Reply to a comment by : K9IUQ on 2007-02-28

Practical Considerations and the Radio Amateur Ok I give up. W4LGH is right, everyone else is wrong. I am going to take down my 130ft centerfed antenna with open feeders (and a ABSURD antenna tuner)that I use for 75,60,40,30 mtrs. And put up REASONANT coax fed dipoles for each band. But wait I know from past experience a dipole won't cover the whole 75 mtr band. I want to to talk to my buddies on the high end of 75 AND pound brass on 3515. So I will need 2 antennas for 75mtr because no way am I going to use the ABSURD antenna tuner and give up half my signal. I surveyed my lot this morning. I have 1 1/2 acre but 1/2 acre is in woods and unsuitable for antennas. I also have a large metal pole barn, which I know will not help my antennas , so I have to stay away from that. Also my powerline is overhead coming in the front of the house. Gotta stay away from that too, plus my xyl doesn't want ANY antenna in the front yard.Also I have a tower with a Log Peridioc beam, I dont want to miss up my dx on 20 mtrs so I have to stay away from that too. Now can someone tell me how I am going to put 5 reasonant dipoles on only a 1 acre lot?? I dont want no trap dipole or fan dipole either. How do you guys do it if you just have a 50 x 100 ft city lot? There MUST be a trick here I am mising. HELP I wannna throw out that damn ABSURD tuner. Where is W4LGH when you need him? Stan K9IUQ
W4LGH2007-02-28
RE: Benchmarks
Ok, where's Stan??? I can't wait to hear what he has to say next?? He's a PLATHERA of information! Maybe he did sell his junk off, took down his non-rez loop?

Nawwwwww...we wouldn't be that lucky!

73 de W4LGH - Alan
Reply to a comment by : KC8QFP on 2007-02-28

I've never seen the Steppir in action. I thought they were Yagi's, but I really don't know much about them. I also was under the impression that they are very $$$, the sky's the limit for many hams, but I am cost conscientious. My little idea can be made CHEAPly. I cannot afford beams, and again I feel the little bit of gain you get for a beam is lost in cost. I like beams and verticals for the VHF and above crowd. And I go with the quad over the Yagi, I have a four el home brew (quad quad) for 2m that works great. Anyhow, I'm am not anti-vertical, but it is difficult to get the length for lower than 40m on a vertical. Wires are easy and cheap. I was going to try two antennaes for 80/40m. (I don't have 160, may consider that some day). I like either mono-bander, offset feed dipoles or inverted vees. Another variation would be a loop. But the antenna that has my attention now and one that I have not tried yet is the HALF SQUARE. That seems to be the better choice for 40m to me. I'll probably keep the Hustler for the higher freqs. I have a dipole for 80, but it tunes for the lower sec of 80m. I want something a little more broad banded with good capture, perhaps a delta loop? Just tossin' ideas about here, that what the facts and figures are all about. Numbers are nice on paper, but real world tends to mess with the numbers, so many variables. I've learned that it is sort of a give and take situation, to get somethings, you usually have to sacrifice something else, i.e. broadband usually means less gain. But I think the Steppir is more like a Cadillac, and I have a Yugo budget! Cheerz, Don
Reply to a comment by : K9IUQ on 2007-02-28

Kc8QFP says Howz about ONE tunable antenna? One antenna that you can change its length. .................................................. Can you spell Steppir? They havent done it with a horizontal dipole yet but they do make a vertical that changes length. I have been the Vertical antenna route many times in my ham career. Have had a Hustler, hygain, Butternut and a couple different Gaps. Most of them never worked as well as my 130ft centerfed with open feedline (with ABSURD antenna tuner). Seems to me at one time I saw a commercial changeable length dipole for sale. You had to change the length manually though which would be a major pain. "One good working antenna that does it all! A Ham's dream come true!" K9IUQ says There are many to pick from, but a resonant dipole is not among of them.... K9IUQ
Reply to a comment by : KC8QFP on 2007-02-28

<<<<< Now can someone tell me how I am going to put 5 reasonant dipoles on only a 1 acre lot?? I dont want no trap dipole or fan dipole either. How do you guys do it if you just have a 50 x 100 ft city lot? There MUST be a trick here I am mising. HELP I wannna throw out that damn ABSURD tuner. Where is W4LGH when you need him? Stan K9IUQ >>>>> Howz about ONE tunable antenna? One antenna that you can change its length. I have a much smaller yard than you, and presently have the Hustler 5BTV which is worthless on 80m. So I have a dipole for that. I tried to tune it for mid band, and my transmitter can handle 3:1. I was going to go with the GAP since it seems so many hams are vertical these days. But I am working on an idea to make a tunable antenna. Counter weights hanging from pulleys at the ends will compensate for the various lengths (but you must have enough height). I got that idea from the counter weights on my windows. The real tricky part would be the feedpoint, a couple of spools (as in a fishing reel) to mechanically adjust the antenna length. A slow RPM motor (I have an old electric screwdriver for that part) would rotate the spools either way (in or out). I was thinking of using BARE wire and metal spools, so as to shunt the coils created by the spools. It may need a cap to nix the impedance bump at the feedpoint, but I think it can work. Of course there must be a contact surface (perhaps brushes) for moving electrical connections. I suppose that it's been tried and true (or not true)? Usually things like this idea needs the kinks worked out, but this is a way to do it with ONE antenna. I bet the SWL's would buy it! The antenna would be the variable inverted VEE or VIV. I am a simple guy (KISS), so you guys with all the brains take it from here. One good working antenna that does it all! A Ham's dream come true! 73, Don
Reply to a comment by : K9IUQ on 2007-02-28

Practical Considerations and the Radio Amateur Ok I give up. W4LGH is right, everyone else is wrong. I am going to take down my 130ft centerfed antenna with open feeders (and a ABSURD antenna tuner)that I use for 75,60,40,30 mtrs. And put up REASONANT coax fed dipoles for each band. But wait I know from past experience a dipole won't cover the whole 75 mtr band. I want to to talk to my buddies on the high end of 75 AND pound brass on 3515. So I will need 2 antennas for 75mtr because no way am I going to use the ABSURD antenna tuner and give up half my signal. I surveyed my lot this morning. I have 1 1/2 acre but 1/2 acre is in woods and unsuitable for antennas. I also have a large metal pole barn, which I know will not help my antennas , so I have to stay away from that. Also my powerline is overhead coming in the front of the house. Gotta stay away from that too, plus my xyl doesn't want ANY antenna in the front yard.Also I have a tower with a Log Peridioc beam, I dont want to miss up my dx on 20 mtrs so I have to stay away from that too. Now can someone tell me how I am going to put 5 reasonant dipoles on only a 1 acre lot?? I dont want no trap dipole or fan dipole either. How do you guys do it if you just have a 50 x 100 ft city lot? There MUST be a trick here I am mising. HELP I wannna throw out that damn ABSURD tuner. Where is W4LGH when you need him? Stan K9IUQ
KC8QFP2007-02-28
RE: Benchmarks
I've never seen the Steppir in action. I thought they were Yagi's, but I really don't know much about them. I also was under the impression that they are very $$$, the sky's the limit for many hams, but I am cost conscientious. My little idea can be made CHEAPly. I cannot afford beams, and again I feel the little bit of gain you get for a beam is lost in cost. I like beams and verticals for the VHF and above crowd. And I go with the quad over the Yagi, I have a four el home brew (quad quad) for 2m that works great. Anyhow, I'm am not anti-vertical, but it is difficult to get the length for lower than 40m on a vertical. Wires are easy and cheap. I was going to try two antennaes for 80/40m. (I don't have 160, may consider that some day). I like either mono-bander, offset feed dipoles or inverted vees. Another variation would be a loop. But the antenna that has my attention now and one that I have not tried yet is the HALF SQUARE. That seems to be the better choice for 40m to me. I'll probably keep the Hustler for the higher freqs. I have a dipole for 80, but it tunes for the lower sec of 80m. I want something a little more broad banded with good capture, perhaps a delta loop? Just tossin' ideas about here, that what the facts and figures are all about. Numbers are nice on paper, but real world tends to mess with the numbers, so many variables. I've learned that it is sort of a give and take situation, to get somethings, you usually have to sacrifice something else, i.e. broadband usually means less gain. But I think the Steppir is more like a Cadillac, and I have a Yugo budget!

Cheerz, Don
Reply to a comment by : K9IUQ on 2007-02-28

Kc8QFP says Howz about ONE tunable antenna? One antenna that you can change its length. .................................................. Can you spell Steppir? They havent done it with a horizontal dipole yet but they do make a vertical that changes length. I have been the Vertical antenna route many times in my ham career. Have had a Hustler, hygain, Butternut and a couple different Gaps. Most of them never worked as well as my 130ft centerfed with open feedline (with ABSURD antenna tuner). Seems to me at one time I saw a commercial changeable length dipole for sale. You had to change the length manually though which would be a major pain. "One good working antenna that does it all! A Ham's dream come true!" K9IUQ says There are many to pick from, but a resonant dipole is not among of them.... K9IUQ
Reply to a comment by : KC8QFP on 2007-02-28

<<<<< Now can someone tell me how I am going to put 5 reasonant dipoles on only a 1 acre lot?? I dont want no trap dipole or fan dipole either. How do you guys do it if you just have a 50 x 100 ft city lot? There MUST be a trick here I am mising. HELP I wannna throw out that damn ABSURD tuner. Where is W4LGH when you need him? Stan K9IUQ >>>>> Howz about ONE tunable antenna? One antenna that you can change its length. I have a much smaller yard than you, and presently have the Hustler 5BTV which is worthless on 80m. So I have a dipole for that. I tried to tune it for mid band, and my transmitter can handle 3:1. I was going to go with the GAP since it seems so many hams are vertical these days. But I am working on an idea to make a tunable antenna. Counter weights hanging from pulleys at the ends will compensate for the various lengths (but you must have enough height). I got that idea from the counter weights on my windows. The real tricky part would be the feedpoint, a couple of spools (as in a fishing reel) to mechanically adjust the antenna length. A slow RPM motor (I have an old electric screwdriver for that part) would rotate the spools either way (in or out). I was thinking of using BARE wire and metal spools, so as to shunt the coils created by the spools. It may need a cap to nix the impedance bump at the feedpoint, but I think it can work. Of course there must be a contact surface (perhaps brushes) for moving electrical connections. I suppose that it's been tried and true (or not true)? Usually things like this idea needs the kinks worked out, but this is a way to do it with ONE antenna. I bet the SWL's would buy it! The antenna would be the variable inverted VEE or VIV. I am a simple guy (KISS), so you guys with all the brains take it from here. One good working antenna that does it all! A Ham's dream come true! 73, Don
Reply to a comment by : K9IUQ on 2007-02-28

Practical Considerations and the Radio Amateur Ok I give up. W4LGH is right, everyone else is wrong. I am going to take down my 130ft centerfed antenna with open feeders (and a ABSURD antenna tuner)that I use for 75,60,40,30 mtrs. And put up REASONANT coax fed dipoles for each band. But wait I know from past experience a dipole won't cover the whole 75 mtr band. I want to to talk to my buddies on the high end of 75 AND pound brass on 3515. So I will need 2 antennas for 75mtr because no way am I going to use the ABSURD antenna tuner and give up half my signal. I surveyed my lot this morning. I have 1 1/2 acre but 1/2 acre is in woods and unsuitable for antennas. I also have a large metal pole barn, which I know will not help my antennas , so I have to stay away from that. Also my powerline is overhead coming in the front of the house. Gotta stay away from that too, plus my xyl doesn't want ANY antenna in the front yard.Also I have a tower with a Log Peridioc beam, I dont want to miss up my dx on 20 mtrs so I have to stay away from that too. Now can someone tell me how I am going to put 5 reasonant dipoles on only a 1 acre lot?? I dont want no trap dipole or fan dipole either. How do you guys do it if you just have a 50 x 100 ft city lot? There MUST be a trick here I am mising. HELP I wannna throw out that damn ABSURD tuner. Where is W4LGH when you need him? Stan K9IUQ
W4LGH2007-02-28
RE: Benchmarks
KC8QFP wrote~" Howz about ONE tunable antenna? One antenna that you can change its length."~

Don...already built one of these, long before StepIr.
You have to use 4 spools, 2 to spool out and 2 to spool in, all in sync from the same motor. On the lower bands it becomes a folded dipole, which broaden the bandwidth, and works out pretty good. When I built mine I used a magnet on one spool to work a reed counter to get it somewhere close, then just rocked it back and forth to tune to RESONANCE. When I built this I was still in Virginia, and we had ice and snow, and it didn't work well as the spools would freeze. However it works GREAT in Florida! Nothing like a RESONANT antenna on every band! But people in this thread don't believe that, guess they don't own StepIRs or talked to someone using one. Also designed one that was a 35' vertical from 40m up, but it didn't work that well, even with radials under it.

The major drawbacks are in freezing weather, the spools freeze up, and it was a tough job mounting the motor/spool assemblies 35/40' in the air, except when you had tower. Trees were a bitch!

73 de W4LGH Alan
http://www.w4lgh.com

Reply to a comment by : K9IUQ on 2007-02-28

Kc8QFP says Howz about ONE tunable antenna? One antenna that you can change its length. .................................................. Can you spell Steppir? They havent done it with a horizontal dipole yet but they do make a vertical that changes length. I have been the Vertical antenna route many times in my ham career. Have had a Hustler, hygain, Butternut and a couple different Gaps. Most of them never worked as well as my 130ft centerfed with open feedline (with ABSURD antenna tuner). Seems to me at one time I saw a commercial changeable length dipole for sale. You had to change the length manually though which would be a major pain. "One good working antenna that does it all! A Ham's dream come true!" K9IUQ says There are many to pick from, but a resonant dipole is not among of them.... K9IUQ
Reply to a comment by : KC8QFP on 2007-02-28

<<<<< Now can someone tell me how I am going to put 5 reasonant dipoles on only a 1 acre lot?? I dont want no trap dipole or fan dipole either. How do you guys do it if you just have a 50 x 100 ft city lot? There MUST be a trick here I am mising. HELP I wannna throw out that damn ABSURD tuner. Where is W4LGH when you need him? Stan K9IUQ >>>>> Howz about ONE tunable antenna? One antenna that you can change its length. I have a much smaller yard than you, and presently have the Hustler 5BTV which is worthless on 80m. So I have a dipole for that. I tried to tune it for mid band, and my transmitter can handle 3:1. I was going to go with the GAP since it seems so many hams are vertical these days. But I am working on an idea to make a tunable antenna. Counter weights hanging from pulleys at the ends will compensate for the various lengths (but you must have enough height). I got that idea from the counter weights on my windows. The real tricky part would be the feedpoint, a couple of spools (as in a fishing reel) to mechanically adjust the antenna length. A slow RPM motor (I have an old electric screwdriver for that part) would rotate the spools either way (in or out). I was thinking of using BARE wire and metal spools, so as to shunt the coils created by the spools. It may need a cap to nix the impedance bump at the feedpoint, but I think it can work. Of course there must be a contact surface (perhaps brushes) for moving electrical connections. I suppose that it's been tried and true (or not true)? Usually things like this idea needs the kinks worked out, but this is a way to do it with ONE antenna. I bet the SWL's would buy it! The antenna would be the variable inverted VEE or VIV. I am a simple guy (KISS), so you guys with all the brains take it from here. One good working antenna that does it all! A Ham's dream come true! 73, Don
Reply to a comment by : K9IUQ on 2007-02-28

Practical Considerations and the Radio Amateur Ok I give up. W4LGH is right, everyone else is wrong. I am going to take down my 130ft centerfed antenna with open feeders (and a ABSURD antenna tuner)that I use for 75,60,40,30 mtrs. And put up REASONANT coax fed dipoles for each band. But wait I know from past experience a dipole won't cover the whole 75 mtr band. I want to to talk to my buddies on the high end of 75 AND pound brass on 3515. So I will need 2 antennas for 75mtr because no way am I going to use the ABSURD antenna tuner and give up half my signal. I surveyed my lot this morning. I have 1 1/2 acre but 1/2 acre is in woods and unsuitable for antennas. I also have a large metal pole barn, which I know will not help my antennas , so I have to stay away from that. Also my powerline is overhead coming in the front of the house. Gotta stay away from that too, plus my xyl doesn't want ANY antenna in the front yard.Also I have a tower with a Log Peridioc beam, I dont want to miss up my dx on 20 mtrs so I have to stay away from that too. Now can someone tell me how I am going to put 5 reasonant dipoles on only a 1 acre lot?? I dont want no trap dipole or fan dipole either. How do you guys do it if you just have a 50 x 100 ft city lot? There MUST be a trick here I am mising. HELP I wannna throw out that damn ABSURD tuner. Where is W4LGH when you need him? Stan K9IUQ
K9IUQ2007-02-28
RE: Benchmarks
Kc8QFP says Howz about ONE tunable antenna? One antenna that you can change its length.

..................................................
Can you spell Steppir? They havent done it with a horizontal dipole yet but they do make a vertical that changes length.

I have been the Vertical antenna route many times in my ham career. Have had a Hustler, hygain, Butternut and a couple different Gaps. Most of them never worked as well as my 130ft centerfed with open feedline (with ABSURD antenna tuner).

Seems to me at one time I saw a commercial changeable length dipole for sale. You had to change the length manually though which would be a major pain.


"One good working antenna that does it all! A Ham's dream come true!"

K9IUQ says There are many to pick from, but a resonant dipole is not among of them....

K9IUQ








Reply to a comment by : KC8QFP on 2007-02-28

<<<<< Now can someone tell me how I am going to put 5 reasonant dipoles on only a 1 acre lot?? I dont want no trap dipole or fan dipole either. How do you guys do it if you just have a 50 x 100 ft city lot? There MUST be a trick here I am mising. HELP I wannna throw out that damn ABSURD tuner. Where is W4LGH when you need him? Stan K9IUQ >>>>> Howz about ONE tunable antenna? One antenna that you can change its length. I have a much smaller yard than you, and presently have the Hustler 5BTV which is worthless on 80m. So I have a dipole for that. I tried to tune it for mid band, and my transmitter can handle 3:1. I was going to go with the GAP since it seems so many hams are vertical these days. But I am working on an idea to make a tunable antenna. Counter weights hanging from pulleys at the ends will compensate for the various lengths (but you must have enough height). I got that idea from the counter weights on my windows. The real tricky part would be the feedpoint, a couple of spools (as in a fishing reel) to mechanically adjust the antenna length. A slow RPM motor (I have an old electric screwdriver for that part) would rotate the spools either way (in or out). I was thinking of using BARE wire and metal spools, so as to shunt the coils created by the spools. It may need a cap to nix the impedance bump at the feedpoint, but I think it can work. Of course there must be a contact surface (perhaps brushes) for moving electrical connections. I suppose that it's been tried and true (or not true)? Usually things like this idea needs the kinks worked out, but this is a way to do it with ONE antenna. I bet the SWL's would buy it! The antenna would be the variable inverted VEE or VIV. I am a simple guy (KISS), so you guys with all the brains take it from here. One good working antenna that does it all! A Ham's dream come true! 73, Don
Reply to a comment by : K9IUQ on 2007-02-28

Practical Considerations and the Radio Amateur Ok I give up. W4LGH is right, everyone else is wrong. I am going to take down my 130ft centerfed antenna with open feeders (and a ABSURD antenna tuner)that I use for 75,60,40,30 mtrs. And put up REASONANT coax fed dipoles for each band. But wait I know from past experience a dipole won't cover the whole 75 mtr band. I want to to talk to my buddies on the high end of 75 AND pound brass on 3515. So I will need 2 antennas for 75mtr because no way am I going to use the ABSURD antenna tuner and give up half my signal. I surveyed my lot this morning. I have 1 1/2 acre but 1/2 acre is in woods and unsuitable for antennas. I also have a large metal pole barn, which I know will not help my antennas , so I have to stay away from that. Also my powerline is overhead coming in the front of the house. Gotta stay away from that too, plus my xyl doesn't want ANY antenna in the front yard.Also I have a tower with a Log Peridioc beam, I dont want to miss up my dx on 20 mtrs so I have to stay away from that too. Now can someone tell me how I am going to put 5 reasonant dipoles on only a 1 acre lot?? I dont want no trap dipole or fan dipole either. How do you guys do it if you just have a 50 x 100 ft city lot? There MUST be a trick here I am mising. HELP I wannna throw out that damn ABSURD tuner. Where is W4LGH when you need him? Stan K9IUQ
KC8QFP2007-02-28
RE: Benchmarks
<<<<< Now can someone tell me how I am going to put 5 reasonant dipoles on only a 1 acre lot?? I dont want no trap dipole or fan dipole either. How do you guys do it if you just have a 50 x 100 ft city lot? There MUST be a trick here I am mising. HELP I wannna throw out that damn ABSURD tuner. Where is W4LGH when you need him?

Stan K9IUQ >>>>>

Howz about ONE tunable antenna? One antenna that you can change its length. I have a much smaller yard than you, and presently have the Hustler 5BTV which is worthless on 80m. So I have a dipole for that. I tried to tune it for mid band, and my transmitter can handle 3:1. I was going to go with the GAP since it seems so many hams are vertical these days.

But I am working on an idea to make a tunable antenna. Counter weights hanging from pulleys at the ends will compensate for the various lengths (but you must have enough height). I got that idea from the counter weights on my windows.

The real tricky part would be the feedpoint, a couple of spools (as in a fishing reel) to mechanically adjust the antenna length. A slow RPM motor (I have an old electric screwdriver for that part) would rotate the spools either way (in or out). I was thinking of using BARE wire and metal spools, so as to shunt the coils created by the spools. It may need a cap to nix the impedance bump at the feedpoint, but I think it can work. Of course there must be a contact surface (perhaps brushes) for moving electrical connections.

I suppose that it's been tried and true (or not true)? Usually things like this idea needs the kinks worked out, but this is a way to do it with ONE antenna. I bet the SWL's would buy it! The antenna would be the variable inverted VEE or VIV.

I am a simple guy (KISS), so you guys with all the brains take it from here. One good working antenna that does it all! A Ham's dream come true!

73, Don
Reply to a comment by : K9IUQ on 2007-02-28

Practical Considerations and the Radio Amateur Ok I give up. W4LGH is right, everyone else is wrong. I am going to take down my 130ft centerfed antenna with open feeders (and a ABSURD antenna tuner)that I use for 75,60,40,30 mtrs. And put up REASONANT coax fed dipoles for each band. But wait I know from past experience a dipole won't cover the whole 75 mtr band. I want to to talk to my buddies on the high end of 75 AND pound brass on 3515. So I will need 2 antennas for 75mtr because no way am I going to use the ABSURD antenna tuner and give up half my signal. I surveyed my lot this morning. I have 1 1/2 acre but 1/2 acre is in woods and unsuitable for antennas. I also have a large metal pole barn, which I know will not help my antennas , so I have to stay away from that. Also my powerline is overhead coming in the front of the house. Gotta stay away from that too, plus my xyl doesn't want ANY antenna in the front yard.Also I have a tower with a Log Peridioc beam, I dont want to miss up my dx on 20 mtrs so I have to stay away from that too. Now can someone tell me how I am going to put 5 reasonant dipoles on only a 1 acre lot?? I dont want no trap dipole or fan dipole either. How do you guys do it if you just have a 50 x 100 ft city lot? There MUST be a trick here I am mising. HELP I wannna throw out that damn ABSURD tuner. Where is W4LGH when you need him? Stan K9IUQ
K8MHZ2007-02-28
RE: Benchmarks
"Since you hold Walt Maxwell in such high esteem (as do I), send him a synopsys of all your claims in this thread."

I have had the great pleasure of meeting Walt. He is a great guy and would probably love to be a part of such a discussion....so long as it is kept civil. He has some great stories about WWII and the FCC. The guy really knows his stuff, too!
Reply to a comment by : W4EF on 2007-02-27

W4LGH wrote: >> walk alone it and watch it light! Coax is shielded and technically does NOT radiate, you can have common mode currents ride the shield back into the shack, especially if your antenna is not resonant, but this energy is rarely if ever radiated, therefore it can NOT be tuned into the antenna system. << Alan, this just simply isn't true. By definition, common-mode current flows on the outside of the coax shield. It always causes radiation. And besides, common-mode current is a red herring with regard to this debate. Antenna feedpoint mismatch doesn't automatically imply common mode feedline current. You can have very high VSWR on both coax and open-wire lines without having feeder current imbalance (i.e. common-mode current). Your comments are so off base on all of this stuff, I simply don't know where to begin. Because, I am working 12 to 14 hour days on my day job, I just don't have time to thoroughly respond to all of the wrong-headed ideas you are presenting here, so I suggest you do the following "real world experiment": Since you hold Walt Maxwell in such high esteem (as do I), send him a synopsys of all your claims in this thread. I'd bet the ranch that he will take exception to much of what you are claiming, especially your notions of common-mode current and antenna resonance. Thanks for the spirited debate. Gotta go (work is calling). 73, Mike W4EF.........................
Reply to a comment by : W4LGH on 2007-02-27

KD2BD writes... "But, remember: This isn't about loss. :-) It's about a claim that a variable impedance matching device at the transmitter operates in a different manner depending on whether the antenna system is coax or open-wire fed, and that open-wire feed "becomes part of the antenna", whereas coax does not. Why the double-standard?" There is no double standard, it is 2 complely different feed systems. Open or balanced line has comsiderable less loss, its non-shielded so it can and does radiate. Simple proof test there too. Take a floursent bulb out and hold it next to the feed line , walk alone it and watch it light! Coax is shielded and technically does NOT radiate, you can have common mode currents ride the shield back into the shack, especially if your antenna is not resonant, but this energy is rarely if ever radiated, therefore it can NOT be tuned into the antenna system. The balanced feed line can and does radiate, so it can be effectively tuned into the antenna system. So there is no dual standard, its 2 completely different ways of getting your RF to the antenna. One works ok with acceptable trade off's, and the other one doesn't. 73 de W4LGH - Alan http://www.w4lgh.com And I am really done this time. This is getting way to old now.
Reply to a comment by : W4LGH on 2007-02-27

K9IUQ wrote~"Finally something we can agree on."~ Now thats damn scary! There is nothing magical about any antenna. If what you have works for you ,then so be it! All antennas are trade off's, even the resonant dipole, you trade off use on other bands. I have the luxury of having resonant dipoles for the major bands I work, my benchmarks so me more power being radiated, and higher receive signals. The losses were to great using a tuner inside for me.
Reply to a comment by : K9IUQ on 2007-02-27

W4LGH says: f you put something up, and it seems to work great, and you can talk to everyone you hear, this is NOT a BENCHMARK...as you don't know who you are NOT hearing. .................................................... Finally something we can agree on. When testing antennas you should always test a new antenna against a known well performing antenna. As one who has put up (and taken down) over a hundred different antennas in his lifetime, the well used term "I can work them if I can hear em " is NOT a benchmark. I have tested your valued resonant coax fed dipole against MANY other antennas in my lifetime. Contrary to what you believe I am not an idiot. Having tested and used over a hundred different antennas, resonant, non resonant and even your valued trap dipole, I can assure you the resonant coax dipole has NO magical properties over many other antennas with or without a tuner. If a resonant coax dipole was magical, better than other antennas, I would be using one. Alas it is not so, hence my present antenna farm looks much like Walter Maxwell's. Not because Walter said so BUT I did my own bencharks thru many years and proved to myself what works best. K9IUQ
W4LGH2007-02-28
RE: Benchmarks
Maybe with a delima this big, you should just sell off your junk and get out of the hobby? The Govt is ultimately going to give it all away anyway.

You guys do whatever you want to do, believe whatever you want to believe. If you are happy with your signal, then so be it. Yall are worse than a lot of the station owners I have worked for over the years, until I proved to them, and showed them better signals in their area.

Any of yall are more than welcome to come over and operate my station, and see for yourself if it works or not. If what you ahve makes you happy then go with it. I done, have fun...gonna go play radio now.

73 de W4LGH - Alan
http://www.w4lgh.com

Reply to a comment by : K9IUQ on 2007-02-28

Practical Considerations and the Radio Amateur Ok I give up. W4LGH is right, everyone else is wrong. I am going to take down my 130ft centerfed antenna with open feeders (and a ABSURD antenna tuner)that I use for 75,60,40,30 mtrs. And put up REASONANT coax fed dipoles for each band. But wait I know from past experience a dipole won't cover the whole 75 mtr band. I want to to talk to my buddies on the high end of 75 AND pound brass on 3515. So I will need 2 antennas for 75mtr because no way am I going to use the ABSURD antenna tuner and give up half my signal. I surveyed my lot this morning. I have 1 1/2 acre but 1/2 acre is in woods and unsuitable for antennas. I also have a large metal pole barn, which I know will not help my antennas , so I have to stay away from that. Also my powerline is overhead coming in the front of the house. Gotta stay away from that too, plus my xyl doesn't want ANY antenna in the front yard.Also I have a tower with a Log Peridioc beam, I dont want to miss up my dx on 20 mtrs so I have to stay away from that too. Now can someone tell me how I am going to put 5 reasonant dipoles on only a 1 acre lot?? I dont want no trap dipole or fan dipole either. How do you guys do it if you just have a 50 x 100 ft city lot? There MUST be a trick here I am mising. HELP I wannna throw out that damn ABSURD tuner. Where is W4LGH when you need him? Stan K9IUQ
K9IUQ2007-02-28
Benchmarks
Practical Considerations and the Radio Amateur

Ok I give up. W4LGH is right, everyone else is wrong. I am going to take down my 130ft centerfed antenna with open feeders (and a ABSURD antenna tuner)that I use for 75,60,40,30 mtrs. And put up REASONANT coax fed dipoles for each band. But wait I know from past experience a dipole won't cover the whole 75 mtr band. I want to to talk to my buddies on the high end of 75 AND pound brass on 3515. So I will need 2 antennas for 75mtr because no way am I going to use the ABSURD antenna tuner and give up half my signal.

I surveyed my lot this morning. I have 1 1/2 acre but 1/2 acre is in woods and unsuitable for antennas. I also have a large metal pole barn, which I know will not help my antennas , so I have to stay away from that. Also my powerline is overhead coming in the front of the house. Gotta stay away from that too, plus my xyl doesn't want ANY antenna in the front yard.Also I have a tower with a Log Peridioc beam, I dont want to miss up my dx on 20 mtrs so I have to stay away from that too.

Now can someone tell me how I am going to put 5 reasonant dipoles on only a 1 acre lot?? I dont want no trap dipole or fan dipole either. How do you guys do it if you just have a 50 x 100 ft city lot? There MUST be a trick here I am mising. HELP I wannna throw out that damn ABSURD tuner. Where is W4LGH when you need him?

Stan K9IUQ
W4EF2007-02-27
RE: Benchmarks
W4LGH wrote:

>> walk alone it and watch it light! Coax is shielded and technically does NOT radiate, you can have common mode currents ride the shield back into the shack, especially if your antenna is not resonant, but this energy is rarely if ever radiated, therefore it can NOT be tuned into the antenna system. <<

Alan, this just simply isn't true. By definition, common-mode current flows on the outside of the coax shield. It always causes radiation. And besides, common-mode current is a red herring with regard to this debate. Antenna feedpoint mismatch doesn't automatically imply common mode feedline current. You can have very high VSWR on both coax and open-wire lines without having feeder current imbalance (i.e. common-mode current).

Your comments are so off base on all of this stuff, I simply don't know where to begin. Because, I am working 12 to 14 hour days on my day job, I just don't have time to thoroughly respond to all of the wrong-headed ideas you are presenting here, so I suggest you do the following "real world experiment": Since you hold Walt Maxwell in such high esteem (as do I), send him a synopsys of all your claims in this thread. I'd bet the ranch that he will take exception to much of what you are claiming, especially your notions of common-mode current and antenna resonance.

Thanks for the spirited debate. Gotta go (work is calling).

73, Mike W4EF.........................
Reply to a comment by : W4LGH on 2007-02-27

KD2BD writes... "But, remember: This isn't about loss. :-) It's about a claim that a variable impedance matching device at the transmitter operates in a different manner depending on whether the antenna system is coax or open-wire fed, and that open-wire feed "becomes part of the antenna", whereas coax does not. Why the double-standard?" There is no double standard, it is 2 complely different feed systems. Open or balanced line has comsiderable less loss, its non-shielded so it can and does radiate. Simple proof test there too. Take a floursent bulb out and hold it next to the feed line , walk alone it and watch it light! Coax is shielded and technically does NOT radiate, you can have common mode currents ride the shield back into the shack, especially if your antenna is not resonant, but this energy is rarely if ever radiated, therefore it can NOT be tuned into the antenna system. The balanced feed line can and does radiate, so it can be effectively tuned into the antenna system. So there is no dual standard, its 2 completely different ways of getting your RF to the antenna. One works ok with acceptable trade off's, and the other one doesn't. 73 de W4LGH - Alan http://www.w4lgh.com And I am really done this time. This is getting way to old now.
Reply to a comment by : W4LGH on 2007-02-27

K9IUQ wrote~"Finally something we can agree on."~ Now thats damn scary! There is nothing magical about any antenna. If what you have works for you ,then so be it! All antennas are trade off's, even the resonant dipole, you trade off use on other bands. I have the luxury of having resonant dipoles for the major bands I work, my benchmarks so me more power being radiated, and higher receive signals. The losses were to great using a tuner inside for me.
Reply to a comment by : K9IUQ on 2007-02-27

W4LGH says: f you put something up, and it seems to work great, and you can talk to everyone you hear, this is NOT a BENCHMARK...as you don't know who you are NOT hearing. .................................................... Finally something we can agree on. When testing antennas you should always test a new antenna against a known well performing antenna. As one who has put up (and taken down) over a hundred different antennas in his lifetime, the well used term "I can work them if I can hear em " is NOT a benchmark. I have tested your valued resonant coax fed dipole against MANY other antennas in my lifetime. Contrary to what you believe I am not an idiot. Having tested and used over a hundred different antennas, resonant, non resonant and even your valued trap dipole, I can assure you the resonant coax dipole has NO magical properties over many other antennas with or without a tuner. If a resonant coax dipole was magical, better than other antennas, I would be using one. Alas it is not so, hence my present antenna farm looks much like Walter Maxwell's. Not because Walter said so BUT I did my own bencharks thru many years and proved to myself what works best. K9IUQ
K9IUQ2007-02-27
Benchmarks
KD2BD says Sorry. None of that is true. Not even close.


73, de John KD2BD
......................................................

The de-bunking of wifes tales continues. John I know you have written many articles, I wonder if you have written much about antennas? The reason I ask is you really have a knack for describing *in simple terms* how things work with antennas. Even I easily understand the concepts you have been writing about. I have read much of Reflections by Walter Maxwell many times. It is an excellent book but I understand only about half of it.

I always hunger for more factual information on antennas, and if you have written anything on the subject I want to read it.

73
Stan K9IUQ

KD2BD2007-02-27
RE: Benchmarks
W4LGH wrote:
>
>> KD2BD writes... "But, remember: This isn't about
>> loss. :-) It's about a claim that a variable
>> impedance matching device at the transmitter
>> operates in a different manner depending on
>> whether the antenna system is coax or open-wire
>> fed, and that open-wire feed "becomes part of the
>> antenna", whereas coax does not. Why the
>> double-standard?"
>
> There is no double standard, it is 2 complely
> different feed systems. Open or balanced line has
> comsiderable less loss, its non-shielded so it can
> and does radiate.

Okay... How can a transmission line radiate, yet be considered to have low loss?

> Simple proof test there too. Take a floursent bulb
> out and hold it next to the feed line , walk alone
> it and watch it light!

(Thankfully, we have more scientific methods of testing RF systems, but, okay, I'll bite.)

The fluorescent lamp lights due to the high electrostatic field (high RF voltage) surrounding the feed line's conductors WITH RESPECT TO THE LAMP'S POTENTIAL, which is somewhat close to a lossy ground potential, especially if you're holding the other end with your hand. This is normal.

You could also coil up a few turns of wire, connect the coil in parallel with a #47 6 volt incandescent lamp, and find it lights when placed close to one side of the feed line, too. That's simply an indication that RF current is flowing through the line. This is also normal behavior.

Neither of these observations proves that the feed line is radiating any substantial amount of electromagnetic energy into anything but the immediate vicinity of the line. All it proves is that there is RF voltage present, and RF current is flowing through the conductors. That doesn't necessarily mean that any significant amount of RF radiation is taking place from the line.

What these simple tests DON'T tell you is the instantaneous phase and direction of current flow (and voltage potential) along the line.

We need to know this to see what's really going on.

A balanced transmission line is (should be) fed DIFFERENTIALLY in terms of current and voltage. At any instant of time, if the left leg is 600 volts positive (with respect to ground), the right leg will be exactly 600 volts negative (with respect to ground).

(The same differential relation applies to current as well.)

A fluorescent lamp (snicker) can't show this.

If you were to stand at a point equidistant from both conductors, you would see a net radiation of ZERO coming from the line because the line's parallel conductors are carrying RF voltages and currents of equal magnitude and opposite polarity, and are very closely spaced in terms of wavelength.

Very close to the line, the situation is different because you are seeing the effects of each conductor individually. (That's why you are supposed to keep twin lead as far away from nearby objects as possible along the run of the line.)

How is this condition being met if you're holding a fluorescent lamp up next to it? What does that say about the validity of the test?

> Coax is shielded and technically does NOT radiate,
> you can have common mode currents ride the shield
> back into the shack, especially if your antenna is
> not resonant, but this energy is rarely if ever
> radiated, therefore it can NOT be tuned into the
> antenna system. The balanced feed line can and does
> radiate, so it can be effectively tuned into the
> antenna system.

Sorry. None of that is true. Not even close.


73, de John KD2BD
Reply to a comment by : W4LGH on 2007-02-27

KD2BD writes... "But, remember: This isn't about loss. :-) It's about a claim that a variable impedance matching device at the transmitter operates in a different manner depending on whether the antenna system is coax or open-wire fed, and that open-wire feed "becomes part of the antenna", whereas coax does not. Why the double-standard?" There is no double standard, it is 2 complely different feed systems. Open or balanced line has comsiderable less loss, its non-shielded so it can and does radiate. Simple proof test there too. Take a floursent bulb out and hold it next to the feed line , walk alone it and watch it light! Coax is shielded and technically does NOT radiate, you can have common mode currents ride the shield back into the shack, especially if your antenna is not resonant, but this energy is rarely if ever radiated, therefore it can NOT be tuned into the antenna system. The balanced feed line can and does radiate, so it can be effectively tuned into the antenna system. So there is no dual standard, its 2 completely different ways of getting your RF to the antenna. One works ok with acceptable trade off's, and the other one doesn't. 73 de W4LGH - Alan http://www.w4lgh.com And I am really done this time. This is getting way to old now.
Reply to a comment by : W4LGH on 2007-02-27

K9IUQ wrote~"Finally something we can agree on."~ Now thats damn scary! There is nothing magical about any antenna. If what you have works for you ,then so be it! All antennas are trade off's, even the resonant dipole, you trade off use on other bands. I have the luxury of having resonant dipoles for the major bands I work, my benchmarks so me more power being radiated, and higher receive signals. The losses were to great using a tuner inside for me.
Reply to a comment by : K9IUQ on 2007-02-27

W4LGH says: f you put something up, and it seems to work great, and you can talk to everyone you hear, this is NOT a BENCHMARK...as you don't know who you are NOT hearing. .................................................... Finally something we can agree on. When testing antennas you should always test a new antenna against a known well performing antenna. As one who has put up (and taken down) over a hundred different antennas in his lifetime, the well used term "I can work them if I can hear em " is NOT a benchmark. I have tested your valued resonant coax fed dipole against MANY other antennas in my lifetime. Contrary to what you believe I am not an idiot. Having tested and used over a hundred different antennas, resonant, non resonant and even your valued trap dipole, I can assure you the resonant coax dipole has NO magical properties over many other antennas with or without a tuner. If a resonant coax dipole was magical, better than other antennas, I would be using one. Alas it is not so, hence my present antenna farm looks much like Walter Maxwell's. Not because Walter said so BUT I did my own bencharks thru many years and proved to myself what works best. K9IUQ
KC8QFP2007-02-27
RE: Benchmarks
Simple, IF you can get most of your RF to radiate from your antenna... BINGO! Badda-bing-badda-boom!

73, Don
Reply to a comment by : N4KC on 2007-02-27

Alan, thank you for posting the details of your tests. Of course, a system that includes a matching device on the transmitter end of a coax feedline that goes to an antenna that is not resonant will show loss commensurate with how far out of resonance the antenna is and how long the coax run is, among other factors. There will also be some loss in the matching device(s), too. It is also true that there will be far less power emitted as RF from the antenna in the above setup than will happen with an antenna operated at one of its resonant frequencies, fed with coax and with no matching device in the line. But furthermore, in the first case, if the antenna is operated at its resonant frequencies, with or without the matching devices in the line, the only real loss will be from the "tuner" and the coax, and it should be low enough to not be a factor. I think where you are catching all the heat is when you say a resonant antenna is always "better" than a non-resonant one. Or that using a "tuner" with coax is "always" a bad thing. Neither statement is true, thanks to the words "better" and "always." If fed with coax and operated only at its resonant frequencies, the coax-fed antenna system is "better" than the same system operated at non-resonant frequencies...but there are a staggering number of those where we can legally operate! If fed with low-loss balanced feedline and matched with a well-designed matching device or devices, the question of resonance is, for all practical purposes, moot. Yes, there will be some places in the spectrum where the system will present complicated reactance combinations that are beyond the capability of a reasonable matching device. But there are plenty of spots where the system will work beautifully. But here's the pregnant question: why would I want to limit myself to only operating on a limited set of frequencies when I could install a single long enough piece of wire in the sky to give me gain on myriad bands and frequencies, and which requires no antenna switching...just a relatively low-loss matching device somewhere in the line? Why would I only consider using resonant antennas and denigrate those who use systems that are non-resonant? I'll answer my own question. The convenience and reliability of coax cable. PL259s are good connectors. I save the couple of hundred bucks a good tuner costs or the time and effort it takes to build a suitable matching device. I don't have access to variable capacitors or inductors. Even if I did, I wouldn't have a clue how to hook them up. I never operate more than a few kHz from the same frequencies anyway, so why bother? Or--and here's the crux of the argument--despite all the evidence to the contrary, I'm still firmly convinced non-resonance is an inherently bad thing--in music, personal relationships, and antennas. I don't believe for a second that non-resonant antenna systems can be just as effective as radiators of RF as resonant ones can. I'm further convinced that standing waves are evil and must be avoided at all costs because that RF energy, once it becomes reflected, is lost forever. 1:1 SWR is not only a worthy goal but the Holy Grail! Some of those are good reasons. Others are woefully misguided. Laws of physics are what they are. It's not a theory. It is fact. Within reasonable systems (no trying to load ten-penny nails or a linguini noodle!), the resonance of an antenna system is a consideration in direct proportion to the loss of the feedline employed as a part of that system. Let me close by saying I use a resonant antenna. It's a telescoping vertical, currently deployed at a quarter wavelength for 15 meters. It is a resonant antenna because it is paired with a field of 85 radials beneath it, each cut to be a quarter wavelength long so the antenna operates efficiently as high as 40 meters (when so telescoped). It presents an SWR of 1.5:1 or better over a reasonable portion of the band. It is fed with coax and I do not use a tuner with it...unless I decide to drop down to 10 meters, where the SWR is considerably higher. The loss in the 100 feet of coax out to the vertical's base is not too bad, but I know I'm losing some energy on 10 meters due to the lost standing waves coursing up and down the coax, becoming less and less virile each trip. But it gets me on 10 for a quick ragchew if I so desire. I also use an antenna that is decidedly non-resonant on literally countless amateur radio frequencies--a horizontal loop, 475 feet long. Yes, there are frequencies--some of them even inside a legal ham band--where even this long hank of wire is resonant. But for the most part, like when I jump from 1.968 on 160 meters, chatting with the gang, to try to catch the Djibouti dxpedition on 30 meters, I have to rely on an external combination of capacitance and inductance to match the output of my TS-2000 to the antenna system for each frequency. It does, very effectively and very quickly (it's a memory tuner), and shows me and my beloved transceiver an SWR of less than 1.5:1. Oh, I'm not kidding myself. There are still standing waves racing down the feedline because the antenna is likely non-resonant at both of those spots in the spectrum. And those standing waves get bounced right back up the feedline at the speed of light. But I'm only losing an infinitesimal amount of that energy on each trip up and down because the feedline is 450-ohm balanced line, with very little resistance to the flow of energy at radio frequencies. And that reflected RF energy eventually gets emitted into space, careening around the ionosphere all the way to Djibouti, where the guys heard my (original) 100 watts well enough to give me a signal report (599, by the way, but I'm not kidding myself about that either!). Oh, I worked them on 15, too, with the resonant vertical. And again with the non-resonant loop. The signal was better on the loop, by the way, which proves nothing except for that path, at that time, considering all the variables involved, the loop was the better antenna system. It might be totally different right now, tomorrow, or next week! Sorry for the long-windedness but I feel passionately about these things. I want everyone in the hobby--or those considering joining the hobby who stick their toe into this swamp we call eHam--to understand the basics of--in this case--antenna systems. It only took me 40 years of ham radio before I finally developed an interest in this part of the hobby, and for me to study enough to grasp the concepts. I appreciate people like the original Alan, who started this chain-yank, W2DU, W4RNL, W8JI, KD2BD, N0AH and others--including W4LGH--for their efforts in doing the experiments and attempting to explain their points of view to those of us who are not EEs or broadcast engineers or have simply not been able to do all that research and study on our own. I still maintain the discourse has been a valuable one for those who have followed it. 73, Don N4KC www.donkeith.com
Reply to a comment by : W4LGH on 2007-02-27

K9IUQ wrote~"Finally something we can agree on."~ Now thats damn scary! There is nothing magical about any antenna. If what you have works for you ,then so be it! All antennas are trade off's, even the resonant dipole, you trade off use on other bands. I have the luxury of having resonant dipoles for the major bands I work, my benchmarks so me more power being radiated, and higher receive signals. The losses were to great using a tuner inside for me.
Reply to a comment by : K9IUQ on 2007-02-27

W4LGH says: f you put something up, and it seems to work great, and you can talk to everyone you hear, this is NOT a BENCHMARK...as you don't know who you are NOT hearing. .................................................... Finally something we can agree on. When testing antennas you should always test a new antenna against a known well performing antenna. As one who has put up (and taken down) over a hundred different antennas in his lifetime, the well used term "I can work them if I can hear em " is NOT a benchmark. I have tested your valued resonant coax fed dipole against MANY other antennas in my lifetime. Contrary to what you believe I am not an idiot. Having tested and used over a hundred different antennas, resonant, non resonant and even your valued trap dipole, I can assure you the resonant coax dipole has NO magical properties over many other antennas with or without a tuner. If a resonant coax dipole was magical, better than other antennas, I would be using one. Alas it is not so, hence my present antenna farm looks much like Walter Maxwell's. Not because Walter said so BUT I did my own bencharks thru many years and proved to myself what works best. K9IUQ
W4LGH2007-02-27
RE: Benchmarks
Well Don, N4KC, I applaude your efforts in this discussion. Especially about the path, and /or band conditions. Which I am affraid is the way most test their antennas, ie: try one today, then one tomorrow and not side by side, @ the same times.

The experiments that I described are real world tests and will do some real world proofs. You also say you are feeding your antennas with balanced line, which I have said from the begining is ok. I still maintain that balanced line hardly stays balanced, in the typical installation and hooked to non-resonant radiators. All of these factors tend to throw the balance off quiet a bit. So when tuning, you are in effect tuning the feed line as well. I have been trying to keep this in the "REAL" world and not in the land where isotropic antennas exsist.

When a tuner is hooked to a coax in your shack, and this coax runs out 100' to your non-resonant antenna, you are NOT tuning your antenna, it is still off resonanace, and it is bouncing currents back into the coax, which can add up to a considerable loss of the actual energy radiated. All you are doing is tuning out the reactance/resistance and matching the impedance back to somewhere around 50ohms, so your transmitter is happy, you are happy, as I think due to urban legends, that most hams really think they are tuning their antenna into resonance and everything is working 100%. This is why I say a turner hooked to coax in your shack is ABSURD. Now the Resonance is always "better" comes from real world tests and actual measurements of the effectiveness of the above non-resonant antenna hooked to 100' of coax to a tuner in your shack, opposed to the same 100' of coax hooked directly to your transmitter on one end and to a resonant antenna on the other end. And you can do this same test over and over in any part of the country and the results will always come out about the same. Maybe this helps explain the "ABSURD" and "BETTER" in my previous posts.

Also I find it interesting that in MOST tuners that I have seen, the balun for feed open line is a 4:1 balun, which will also show loss as you are feeding 450ohms with 200ohms! You can always feed a HIGH with a LOW, but with a LOSS in energy transfered. Anyway..
thats is where I am coming from. Been tried and tested many times...

Enjoy!
de W4LGH - Alan
http://www.w4lgh.com
Reply to a comment by : N4KC on 2007-02-27

Alan, thank you for posting the details of your tests. Of course, a system that includes a matching device on the transmitter end of a coax feedline that goes to an antenna that is not resonant will show loss commensurate with how far out of resonance the antenna is and how long the coax run is, among other factors. There will also be some loss in the matching device(s), too. It is also true that there will be far less power emitted as RF from the antenna in the above setup than will happen with an antenna operated at one of its resonant frequencies, fed with coax and with no matching device in the line. But furthermore, in the first case, if the antenna is operated at its resonant frequencies, with or without the matching devices in the line, the only real loss will be from the "tuner" and the coax, and it should be low enough to not be a factor. I think where you are catching all the heat is when you say a resonant antenna is always "better" than a non-resonant one. Or that using a "tuner" with coax is "always" a bad thing. Neither statement is true, thanks to the words "better" and "always." If fed with coax and operated only at its resonant frequencies, the coax-fed antenna system is "better" than the same system operated at non-resonant frequencies...but there are a staggering number of those where we can legally operate! If fed with low-loss balanced feedline and matched with a well-designed matching device or devices, the question of resonance is, for all practical purposes, moot. Yes, there will be some places in the spectrum where the system will present complicated reactance combinations that are beyond the capability of a reasonable matching device. But there are plenty of spots where the system will work beautifully. But here's the pregnant question: why would I want to limit myself to only operating on a limited set of frequencies when I could install a single long enough piece of wire in the sky to give me gain on myriad bands and frequencies, and which requires no antenna switching...just a relatively low-loss matching device somewhere in the line? Why would I only consider using resonant antennas and denigrate those who use systems that are non-resonant? I'll answer my own question. The convenience and reliability of coax cable. PL259s are good connectors. I save the couple of hundred bucks a good tuner costs or the time and effort it takes to build a suitable matching device. I don't have access to variable capacitors or inductors. Even if I did, I wouldn't have a clue how to hook them up. I never operate more than a few kHz from the same frequencies anyway, so why bother? Or--and here's the crux of the argument--despite all the evidence to the contrary, I'm still firmly convinced non-resonance is an inherently bad thing--in music, personal relationships, and antennas. I don't believe for a second that non-resonant antenna systems can be just as effective as radiators of RF as resonant ones can. I'm further convinced that standing waves are evil and must be avoided at all costs because that RF energy, once it becomes reflected, is lost forever. 1:1 SWR is not only a worthy goal but the Holy Grail! Some of those are good reasons. Others are woefully misguided. Laws of physics are what they are. It's not a theory. It is fact. Within reasonable systems (no trying to load ten-penny nails or a linguini noodle!), the resonance of an antenna system is a consideration in direct proportion to the loss of the feedline employed as a part of that system. Let me close by saying I use a resonant antenna. It's a telescoping vertical, currently deployed at a quarter wavelength for 15 meters. It is a resonant antenna because it is paired with a field of 85 radials beneath it, each cut to be a quarter wavelength long so the antenna operates efficiently as high as 40 meters (when so telescoped). It presents an SWR of 1.5:1 or better over a reasonable portion of the band. It is fed with coax and I do not use a tuner with it...unless I decide to drop down to 10 meters, where the SWR is considerably higher. The loss in the 100 feet of coax out to the vertical's base is not too bad, but I know I'm losing some energy on 10 meters due to the lost standing waves coursing up and down the coax, becoming less and less virile each trip. But it gets me on 10 for a quick ragchew if I so desire. I also use an antenna that is decidedly non-resonant on literally countless amateur radio frequencies--a horizontal loop, 475 feet long. Yes, there are frequencies--some of them even inside a legal ham band--where even this long hank of wire is resonant. But for the most part, like when I jump from 1.968 on 160 meters, chatting with the gang, to try to catch the Djibouti dxpedition on 30 meters, I have to rely on an external combination of capacitance and inductance to match the output of my TS-2000 to the antenna system for each frequency. It does, very effectively and very quickly (it's a memory tuner), and shows me and my beloved transceiver an SWR of less than 1.5:1. Oh, I'm not kidding myself. There are still standing waves racing down the feedline because the antenna is likely non-resonant at both of those spots in the spectrum. And those standing waves get bounced right back up the feedline at the speed of light. But I'm only losing an infinitesimal amount of that energy on each trip up and down because the feedline is 450-ohm balanced line, with very little resistance to the flow of energy at radio frequencies. And that reflected RF energy eventually gets emitted into space, careening around the ionosphere all the way to Djibouti, where the guys heard my (original) 100 watts well enough to give me a signal report (599, by the way, but I'm not kidding myself about that either!). Oh, I worked them on 15, too, with the resonant vertical. And again with the non-resonant loop. The signal was better on the loop, by the way, which proves nothing except for that path, at that time, considering all the variables involved, the loop was the better antenna system. It might be totally different right now, tomorrow, or next week! Sorry for the long-windedness but I feel passionately about these things. I want everyone in the hobby--or those considering joining the hobby who stick their toe into this swamp we call eHam--to understand the basics of--in this case--antenna systems. It only took me 40 years of ham radio before I finally developed an interest in this part of the hobby, and for me to study enough to grasp the concepts. I appreciate people like the original Alan, who started this chain-yank, W2DU, W4RNL, W8JI, KD2BD, N0AH and others--including W4LGH--for their efforts in doing the experiments and attempting to explain their points of view to those of us who are not EEs or broadcast engineers or have simply not been able to do all that research and study on our own. I still maintain the discourse has been a valuable one for those who have followed it. 73, Don N4KC www.donkeith.com
Reply to a comment by : W4LGH on 2007-02-27

K9IUQ wrote~"Finally something we can agree on."~ Now thats damn scary! There is nothing magical about any antenna. If what you have works for you ,then so be it! All antennas are trade off's, even the resonant dipole, you trade off use on other bands. I have the luxury of having resonant dipoles for the major bands I work, my benchmarks so me more power being radiated, and higher receive signals. The losses were to great using a tuner inside for me.
Reply to a comment by : K9IUQ on 2007-02-27

W4LGH says: f you put something up, and it seems to work great, and you can talk to everyone you hear, this is NOT a BENCHMARK...as you don't know who you are NOT hearing. .................................................... Finally something we can agree on. When testing antennas you should always test a new antenna against a known well performing antenna. As one who has put up (and taken down) over a hundred different antennas in his lifetime, the well used term "I can work them if I can hear em " is NOT a benchmark. I have tested your valued resonant coax fed dipole against MANY other antennas in my lifetime. Contrary to what you believe I am not an idiot. Having tested and used over a hundred different antennas, resonant, non resonant and even your valued trap dipole, I can assure you the resonant coax dipole has NO magical properties over many other antennas with or without a tuner. If a resonant coax dipole was magical, better than other antennas, I would be using one. Alas it is not so, hence my present antenna farm looks much like Walter Maxwell's. Not because Walter said so BUT I did my own bencharks thru many years and proved to myself what works best. K9IUQ
N4KC2007-02-27
RE: Benchmarks
Alan, thank you for posting the details of your tests. Of course, a system that includes a matching device on the transmitter end of a coax feedline that goes to an antenna that is not resonant will show loss commensurate with how far out of resonance the antenna is and how long the coax run is, among other factors. There will also be some loss in the matching device(s), too.

It is also true that there will be far less power emitted as RF from the antenna in the above setup than will happen with an antenna operated at one of its resonant frequencies, fed with coax and with no matching device in the line.

But furthermore, in the first case, if the antenna is operated at its resonant frequencies, with or without the matching devices in the line, the only real loss will be from the "tuner" and the coax, and it should be low enough to not be a factor.

I think where you are catching all the heat is when you say a resonant antenna is always "better" than a non-resonant one. Or that using a "tuner" with coax is "always" a bad thing. Neither statement is true, thanks to the words "better" and "always." If fed with coax and operated only at its resonant frequencies, the coax-fed antenna system is "better" than the same system operated at non-resonant frequencies...but there are a staggering number of those where we can legally operate!

If fed with low-loss balanced feedline and matched with a well-designed matching device or devices, the question of resonance is, for all practical purposes, moot. Yes, there will be some places in the spectrum where the system will present complicated reactance combinations that are beyond the capability of a reasonable matching device. But there are plenty of spots where the system will work beautifully.

But here's the pregnant question: why would I want to limit myself to only operating on a limited set of frequencies when I could install a single long enough piece of wire in the sky to give me gain on myriad bands and frequencies, and which requires no antenna switching...just a relatively low-loss matching device somewhere in the line?

Why would I only consider using resonant antennas and denigrate those who use systems that are non-resonant?

I'll answer my own question. The convenience and reliability of coax cable. PL259s are good connectors. I save the couple of hundred bucks a good tuner costs or the time and effort it takes to build a suitable matching device. I don't have access to variable capacitors or inductors. Even if I did, I wouldn't have a clue how to hook them up. I never operate more than a few kHz from the same frequencies anyway, so why bother?

Or--and here's the crux of the argument--despite all the evidence to the contrary, I'm still firmly convinced non-resonance is an inherently bad thing--in music, personal relationships, and antennas. I don't believe for a second that non-resonant antenna systems can be just as effective as radiators of RF as resonant ones can. I'm further convinced that standing waves are evil and must be avoided at all costs because that RF energy, once it becomes reflected, is lost forever. 1:1 SWR is not only a worthy goal but the Holy Grail!

Some of those are good reasons. Others are woefully misguided. Laws of physics are what they are. It's not a theory. It is fact. Within reasonable systems (no trying to load ten-penny nails or a linguini noodle!), the resonance of an antenna system is a consideration in direct proportion to the loss of the feedline employed as a part of that system.

Let me close by saying I use a resonant antenna. It's a telescoping vertical, currently deployed at a quarter wavelength for 15 meters. It is a resonant antenna because it is paired with a field of 85 radials beneath it, each cut to be a quarter wavelength long so the antenna operates efficiently as high as 40 meters (when so telescoped). It presents an SWR of 1.5:1 or better over a reasonable portion of the band. It is fed with coax and I do not use a tuner with it...unless I decide to drop down to 10 meters, where the SWR is considerably higher. The loss in the 100 feet of coax out to the vertical's base is not too bad, but I know I'm losing some energy on 10 meters due to the lost standing waves coursing up and down the coax, becoming less and less virile each trip. But it gets me on 10 for a quick ragchew if I so desire.

I also use an antenna that is decidedly non-resonant on literally countless amateur radio frequencies--a horizontal loop, 475 feet long. Yes, there are frequencies--some of them even inside a legal ham band--where even this long hank of wire is resonant. But for the most part, like when I jump from 1.968 on 160 meters, chatting with the gang, to try to catch the Djibouti dxpedition on 30 meters, I have to rely on an external combination of capacitance and inductance to match the output of my TS-2000 to the antenna system for each frequency. It does, very effectively and very quickly (it's a memory tuner), and shows me and my beloved transceiver an SWR of less than 1.5:1.

Oh, I'm not kidding myself. There are still standing waves racing down the feedline because the antenna is likely non-resonant at both of those spots in the spectrum. And those standing waves get bounced right back up the feedline at the speed of light. But I'm only losing an infinitesimal amount of that energy on each trip up and down because the feedline is 450-ohm balanced line, with very little resistance to the flow of energy at radio frequencies. And that reflected RF energy eventually gets emitted into space, careening around the ionosphere all the way to Djibouti, where the guys heard my (original) 100 watts well enough to give me a signal report (599, by the way, but I'm not kidding myself about that either!).

Oh, I worked them on 15, too, with the resonant vertical. And again with the non-resonant loop. The signal was better on the loop, by the way, which proves nothing except for that path, at that time, considering all the variables involved, the loop was the better antenna system. It might be totally different right now, tomorrow, or next week!

Sorry for the long-windedness but I feel passionately about these things. I want everyone in the hobby--or those considering joining the hobby who stick their toe into this swamp we call eHam--to understand the basics of--in this case--antenna systems. It only took me 40 years of ham radio before I finally developed an interest in this part of the hobby, and for me to study enough to grasp the concepts. I appreciate people like the original Alan, who started this chain-yank, W2DU, W4RNL, W8JI, KD2BD, N0AH and others--including W4LGH--for their efforts in doing the experiments and attempting to explain their points of view to those of us who are not EEs or broadcast engineers or have simply not been able to do all that research and study on our own.

I still maintain the discourse has been a valuable one for those who have followed it.

73,

Don N4KC
www.donkeith.com




Reply to a comment by : W4LGH on 2007-02-27

K9IUQ wrote~"Finally something we can agree on."~ Now thats damn scary! There is nothing magical about any antenna. If what you have works for you ,then so be it! All antennas are trade off's, even the resonant dipole, you trade off use on other bands. I have the luxury of having resonant dipoles for the major bands I work, my benchmarks so me more power being radiated, and higher receive signals. The losses were to great using a tuner inside for me.
Reply to a comment by : K9IUQ on 2007-02-27

W4LGH says: f you put something up, and it seems to work great, and you can talk to everyone you hear, this is NOT a BENCHMARK...as you don't know who you are NOT hearing. .................................................... Finally something we can agree on. When testing antennas you should always test a new antenna against a known well performing antenna. As one who has put up (and taken down) over a hundred different antennas in his lifetime, the well used term "I can work them if I can hear em " is NOT a benchmark. I have tested your valued resonant coax fed dipole against MANY other antennas in my lifetime. Contrary to what you believe I am not an idiot. Having tested and used over a hundred different antennas, resonant, non resonant and even your valued trap dipole, I can assure you the resonant coax dipole has NO magical properties over many other antennas with or without a tuner. If a resonant coax dipole was magical, better than other antennas, I would be using one. Alas it is not so, hence my present antenna farm looks much like Walter Maxwell's. Not because Walter said so BUT I did my own bencharks thru many years and proved to myself what works best. K9IUQ
K9IUQ2007-02-27
Benchmarks
K6IOU says Open wire balanced feedlines DO NOT radiate if they remain balanced.

Just when I thought there was an upper limit to the mis-information that Alan [W4LGH] could propagate he surprises me with more.
..................................................

I was just getting ready to say the same thing. ANYONE that has read ANY antenna handbook KNOWS the first statement is correct.

Unfortunately the W4LGH's of the world continue to spew their mis-information unwilling to read even a basic antenna book. Fortunately when some one like W4LGH speaks in a public forum like eham his mis-information is shown for what it really is.

W4LGH *might* get his antenna crap lies to fly with his buddies on 75 mtrs but on eham where there are MANY very smart hams it is easy to prove him wrong.

Stan K9IUQ




K6IOU2007-02-27
RE: Benchmarks
Jeez . . .

Just when I thought there was an upper limit to the mis-information that Alan [W4LGH] could propagate he surprises me with more.

Open wire balanced feedlines DO NOT radiate if they remain balanced. Admittedly in most amateur installations they 'may' not be perfectly balanced . . . but 'that' is the reason they radiate, not because they are 'not shielded'.

Common mode currents on the outside shield of coax most definitely DO radiate.

Finally . . . SWR on a feedline does not cause it to radiate. Imbalance does.

Re-read the ARRL Antenna Handbook!

[120' CF Dipole, 405 ohm balanced line, antenna tuner. Work all bands 80m thru 10m]

DON
K6IOU
Reply to a comment by : W4LGH on 2007-02-27

KD2BD writes... "But, remember: This isn't about loss. :-) It's about a claim that a variable impedance matching device at the transmitter operates in a different manner depending on whether the antenna system is coax or open-wire fed, and that open-wire feed "becomes part of the antenna", whereas coax does not. Why the double-standard?" There is no double standard, it is 2 complely different feed systems. Open or balanced line has comsiderable less loss, its non-shielded so it can and does radiate. Simple proof test there too. Take a floursent bulb out and hold it next to the feed line , walk alone it and watch it light! Coax is shielded and technically does NOT radiate, you can have common mode currents ride the shield back into the shack, especially if your antenna is not resonant, but this energy is rarely if ever radiated, therefore it can NOT be tuned into the antenna system. The balanced feed line can and does radiate, so it can be effectively tuned into the antenna system. So there is no dual standard, its 2 completely different ways of getting your RF to the antenna. One works ok with acceptable trade off's, and the other one doesn't. 73 de W4LGH - Alan http://www.w4lgh.com And I am really done this time. This is getting way to old now.
Reply to a comment by : W4LGH on 2007-02-27

K9IUQ wrote~"Finally something we can agree on."~ Now thats damn scary! There is nothing magical about any antenna. If what you have works for you ,then so be it! All antennas are trade off's, even the resonant dipole, you trade off use on other bands. I have the luxury of having resonant dipoles for the major bands I work, my benchmarks so me more power being radiated, and higher receive signals. The losses were to great using a tuner inside for me.
Reply to a comment by : K9IUQ on 2007-02-27

W4LGH says: f you put something up, and it seems to work great, and you can talk to everyone you hear, this is NOT a BENCHMARK...as you don't know who you are NOT hearing. .................................................... Finally something we can agree on. When testing antennas you should always test a new antenna against a known well performing antenna. As one who has put up (and taken down) over a hundred different antennas in his lifetime, the well used term "I can work them if I can hear em " is NOT a benchmark. I have tested your valued resonant coax fed dipole against MANY other antennas in my lifetime. Contrary to what you believe I am not an idiot. Having tested and used over a hundred different antennas, resonant, non resonant and even your valued trap dipole, I can assure you the resonant coax dipole has NO magical properties over many other antennas with or without a tuner. If a resonant coax dipole was magical, better than other antennas, I would be using one. Alas it is not so, hence my present antenna farm looks much like Walter Maxwell's. Not because Walter said so BUT I did my own bencharks thru many years and proved to myself what works best. K9IUQ
W4LGH2007-02-27
RE: Benchmarks
KD2BD writes... "But, remember: This isn't about loss. :-) It's about a claim that a variable impedance matching device at the transmitter operates in a different manner depending on whether the antenna system is coax or open-wire fed, and that open-wire feed "becomes part of the antenna", whereas coax does not. Why the double-standard?"

There is no double standard, it is 2 complely different feed systems. Open or balanced line has comsiderable less loss, its non-shielded so it can and does radiate. Simple proof test there too. Take a floursent bulb out and hold it next to the feed line , walk alone it and watch it light! Coax is shielded and technically does NOT radiate, you can have common mode currents ride the shield back into the shack, especially if your antenna is not resonant, but this energy is rarely if ever radiated, therefore it can NOT be tuned into the antenna system. The balanced feed line can and does radiate, so it can be effectively tuned into the antenna system. So there is no dual standard, its 2 completely different ways of getting your RF to the antenna.

One works ok with acceptable trade off's, and the other one doesn't.

73 de W4LGH - Alan
http://www.w4lgh.com

And I am really done this time. This is getting way to old now.
Reply to a comment by : W4LGH on 2007-02-27

K9IUQ wrote~"Finally something we can agree on."~ Now thats damn scary! There is nothing magical about any antenna. If what you have works for you ,then so be it! All antennas are trade off's, even the resonant dipole, you trade off use on other bands. I have the luxury of having resonant dipoles for the major bands I work, my benchmarks so me more power being radiated, and higher receive signals. The losses were to great using a tuner inside for me.
Reply to a comment by : K9IUQ on 2007-02-27

W4LGH says: f you put something up, and it seems to work great, and you can talk to everyone you hear, this is NOT a BENCHMARK...as you don't know who you are NOT hearing. .................................................... Finally something we can agree on. When testing antennas you should always test a new antenna against a known well performing antenna. As one who has put up (and taken down) over a hundred different antennas in his lifetime, the well used term "I can work them if I can hear em " is NOT a benchmark. I have tested your valued resonant coax fed dipole against MANY other antennas in my lifetime. Contrary to what you believe I am not an idiot. Having tested and used over a hundred different antennas, resonant, non resonant and even your valued trap dipole, I can assure you the resonant coax dipole has NO magical properties over many other antennas with or without a tuner. If a resonant coax dipole was magical, better than other antennas, I would be using one. Alas it is not so, hence my present antenna farm looks much like Walter Maxwell's. Not because Walter said so BUT I did my own bencharks thru many years and proved to myself what works best. K9IUQ
W4LGH2007-02-27
RE: Benchmarks
K9IUQ wrote~"Finally something we can agree on."~

Now thats damn scary! There is nothing magical about any antenna. If what you have works for you ,then so be it!

All antennas are trade off's, even the resonant dipole, you trade off use on other bands. I have the luxury of having resonant dipoles for the major bands I work, my benchmarks so me more power being radiated, and higher receive signals.

The losses were to great using a tuner inside for me.

Reply to a comment by : K9IUQ on 2007-02-27

W4LGH says: f you put something up, and it seems to work great, and you can talk to everyone you hear, this is NOT a BENCHMARK...as you don't know who you are NOT hearing. .................................................... Finally something we can agree on. When testing antennas you should always test a new antenna against a known well performing antenna. As one who has put up (and taken down) over a hundred different antennas in his lifetime, the well used term "I can work them if I can hear em " is NOT a benchmark. I have tested your valued resonant coax fed dipole against MANY other antennas in my lifetime. Contrary to what you believe I am not an idiot. Having tested and used over a hundred different antennas, resonant, non resonant and even your valued trap dipole, I can assure you the resonant coax dipole has NO magical properties over many other antennas with or without a tuner. If a resonant coax dipole was magical, better than other antennas, I would be using one. Alas it is not so, hence my present antenna farm looks much like Walter Maxwell's. Not because Walter said so BUT I did my own bencharks thru many years and proved to myself what works best. K9IUQ
KD2BD2007-02-27
RE: Benchmarks
N3OX wrote:

>> KD2BD says:
>>
>>
>> "What if we increased the length to 1 foot? How
>> about 10 feet? How about 100 feet? At what magic
>> length would you say the use of coaxial line would
>> start to have a detrimental effect on the tuning
>> of the system over an identical length of ladder
>> line? "
>
> Exactly!
>
> (I'd answer "One dB" except that I don't want to
> muddy the waters too much... everyone knows a dB
> isn't a length ;-) )
>
>
> And I'd have to take out the "tuning of the system"
> part to answer 1dB.

Absolutely.

But, remember: This isn't about loss. :-) It's about a claim that a variable impedance matching device at the transmitter operates in a different manner depending on whether the antenna system is coax or open-wire fed, and that open-wire feed "becomes part of the antenna", whereas coax does not.

Why the double-standard?

W4LGH is not the first to make these claims. I've heard them too, many times in my early days as a ham, and believed them myself for a length of time I would be too embarrassed to admit.

But they were wrong. And I was wrong for blindly believing them without questioning their validity.

RF is tricky business. We are fortunate to be part of a Radio Service that allows us to dig our hands into the innermost workings of a communications system, and see first hand what works, how it works, and share our experiences with others.

Sometimes this process fosters confusion because what we see (and come to believe through our experiences) does not always accurately describe what's really going on.

It is encouraging to see those who DO see and understand the "big picture" take time in this discussion to help explain what's really going on, and to try to dispel some of the many Urban Legends that are part of the culture of Amateur Radio.


73, de John, KD2BD
Reply to a comment by : N3OX on 2007-02-26

KD2BD says: "What if we increased the length to 1 foot? How about 10 feet? How about 100 feet? At what magic length would you say the use of coaxial line would start to have a detrimental effect on the tuning of the system over an identical length of ladder line? " Exactly! (I'd answer "One dB" except that I don't want to muddy the waters too much... everyone knows a dB isn't a length ;-) ) Dan
Reply to a comment by : KC8QFP on 2007-02-26

Trivial PS: I noticed that in my list of ancient antique confusers, I forgot to mention the Compaq, IBM PC and its clones. The IBM SIG was the place to be! 73, Don
Reply to a comment by : KC8QFP on 2007-02-26

I learned something a long time ago on the Cleveland Freenet (the beginnings of the public access to the internet before there was the WWW). Some of the professors and engineers at CWRU (Case Western Reserve University was home of Cleve Freenet) were the guru's of the computer SIG, and we that had Tandy 1000's - Coco's - Trash 80's, Kaypro's, Apple II's (Freenet originally ran on an Apple ii), even Timex, Commies, Atari, and perhaps the infamous TI99/4 could get on and pick their brains. Same with the law and med students/professors. I learned that these brilliant people DONATED their time for us morons like me. They got a lot of $$$ to teach, lecture, and for any other use of their time. But I got to know some of these guys personally, truely amazing people, and I really appreciated their helping me out with their expertise. I have a lot of respect and admiration for those talanted people that ""elmered"" many a student to have a great career in engineering or whatever. It was sort of like getting some college education for FREE, thanks to their generousity. But I also learn that there were some jerks that did not really appreciate the Freenet, and they did the slamming, flaming, and other typical making an ass of themselves. I was a sysop, and I had to kick some of those jerks off the Freenet because we tried to keep a bar of integrity. My old email was ab064@freenet.org, and aa960 as handicap sigop ID. He are benefitted here on eham with some professional people that freely give their time, and at least I appreciate it. There's always a smartass in the crowd, and we had plenty on Freenet, especially in its chat rooms (I was not interesed in the chat, but heard plenty about it at Freenet get togethers). Thankfully the guru's did not say the hell with it and let the bozo's spoil it for the rest of the decent people. So that's it for soapbox speeches, let's show some grattitude to the guys that we can learn something from. This should not be a battle of nit-witts, but rather compairring notes and sharring of ideas. Now play nice boyzzz! Don
Reply to a comment by : W4LGH on 2007-02-26

K9IUQ wrote...There is a very good reason for this. Professional Installations DONT change frequency. Most ham are frequency agile, that is they don't stay on one frequency like a Professional Installation Does. When you change frequencys like most hams do, the situation changes, hence a tuner in the shack. Hahahahahahahahahaha...now thats about as good of logic as manufactures building ant. tuners into the radios because they are a good thing! Stan you are grabing at straws but you are still sinking into the quicksand. I have changed frequencies on many professional installation, walk out and re-tune the transmatch. The fact the tuner is at the antenna is because it is more effeceint and it actually LOADS the antenna into resonance! YOu're still trying to push, but I am not gonna move. I appologized to you for letting you push me into calling you a F#*KING IDIOT in public, and I sincerely appologize for that, as I should have been bigger than that, but it certainly doesn't change how I feel about you, and you just keep proving it! Maybe one day the light will come on... NOT!!! Modist or not modist, I am proud of my knowledge, and I only share it to try and help others. Do as you wish, its no sweat off my back, and you are probably afraid to try the simple experiments I described earlier as they WILL bust your bubble! Been there done that and have the T-Shirt! Long hard road..and you can keep busting your head along the way. This is it, you are going to believe what you want to, and this ole world is just like BurgerKing...you can have it your way. 73 de W4LGH - ALan http://www.w4lgh.com
Reply to a comment by : K9IUQ on 2007-02-26

Kd2BD says A little bit. :-) ....................................................... Why is it the truly smart hams are so modest and the ones that *think* they are smart and want everyone to know it say I am a BROADCAST ENGINEER (at least 6 times) and put their website in every post so everyone sees how smart they are? I respect you John, but you are too modest. I will help you, here is John's credentials: http://www.qsl.net/kd2bd/index.html Stan K9IUQ
K9IUQ2007-02-27
Benchmarks
W4LGH says: f you put something up, and it seems to work great, and you can talk to everyone you hear, this is NOT a BENCHMARK...as you don't know who you are NOT hearing.

....................................................
Finally something we can agree on. When testing antennas you should always test a new antenna against a known well performing antenna. As one who has put up (and taken down) over a hundred different antennas in his lifetime, the well used term "I can work them if I can hear em " is NOT a benchmark.

I have tested your valued resonant coax fed dipole against MANY other antennas in my lifetime. Contrary to what you believe I am not an idiot. Having tested and used over a hundred different antennas, resonant, non resonant and even your valued trap dipole, I can assure you the resonant coax dipole has NO magical properties over many other antennas with or without a tuner.

If a resonant coax dipole was magical, better than other antennas, I would be using one. Alas it is not so, hence my present antenna farm looks much like Walter Maxwell's. Not because Walter said so BUT I did my own bencharks thru many years and proved to myself what works best.

K9IUQ
W4LGH2007-02-27
RE: Benchmarks
If everyone would go back to the original article and READ it, it is about setting BENCHMARKS. The tests I described above set up these BENCHMARKS. I never said a random wire fed with coax into a tuner did NOT work, I said a RESONANT antenna fed the same way was better.

If you put something up, and it seems to work great, and you can talk to everyone you hear, this is NOT a BENCHMARK...as you don't know who you are NOT hearing.

I still say that using an antenna tuner in your shack fed with un-balanced coax, in the typical shack installation, that you are only fooling yourself. 75%
of the installs I have seen, use RG-8X, own an MFJ tuner with a preset selectable inductor. It will look like its loading the antenna system, but maybe only radiating 15 or your 100watts, due to losses. So with that I say it is still "absurd" to do this.

In a perfect world an antenna is reciprocal from tranmit to receive, but we don't live in this perfect world, and many varibles come into play. Just like an Isotropic antenna, that mystery antenna that doesn't exsist, but everything is compaired to.

Try it...
73 de W4LGH Alan
http://www.w4lgh.com
Reply to a comment by : K9IUQ on 2007-02-27

N4KC says Truism #10: A wire dipole, cut to at least a half wavelength long on the lowest proposed operating frequency, and fed with ladder/window/open wire feedline, properly matched with a good matching device that may include a current balun, is a very good antenna system for both transmitting and receiving. The higher above ground it is hung, the better (with a few exceptions that affect angle of radiation). It is at least the equal of a resonant dipole, fed with good quality coax, that is being operated on its "resonant" frequency. It is certainly better than that coax-fed dipole once the operator ventures off that resonant spot in the spectrum. ....................................................... I have used just such an antenna off and on for 46 years. A 130 ft wire fed with open feeders and (horrors) a tuner. It is probably the best all band antenna you can use. This antenna is actually better (it has gain) than a resonant coax fed dipoles on all band 40 mtrs and higher. You can prove this by modeling it in EZNEC software as I have done many times.This antenna is timeless, hams 70 yrs ago knew it worked great and smart hams today know it too, in spite of wifes tales like "resonant coax fed antennas are better". Your example of loops fed with open fedders is right on also. I also have a 277 ft loop fed with open feeders and a (horrors) tuner. This antenna is the equal to the 130ft and is also quieter on rx. I suspect it also has gain on 40mtrs and higher but haven't modeled it in EZNEC yet. I use the above antennas on 75,40,60,30 mtrs with great success. Stan K9IUQ
K9IUQ2007-02-27
Benchmarks
N4KC says Truism #10: A wire dipole, cut to at least a half wavelength long on the lowest proposed operating frequency, and fed with ladder/window/open wire feedline, properly matched with a good matching device that may include a current balun, is a very good antenna system for both transmitting and receiving. The higher above ground it is hung, the better (with a few exceptions that affect angle of radiation). It is at least the equal of a resonant dipole, fed with good quality coax, that is being operated on its "resonant" frequency. It is certainly better than that coax-fed dipole once the operator ventures off that resonant spot in the spectrum.
.......................................................
I have used just such an antenna off and on for 46 years. A 130 ft wire fed with open feeders and (horrors) a tuner. It is probably the best all band antenna you can use. This antenna is actually better (it has gain) than a resonant coax fed dipoles on all band 40 mtrs and higher. You can prove this by modeling it in EZNEC software as I have done many times.This antenna is timeless, hams 70 yrs ago knew it worked great and smart hams today know it too, in spite of wifes tales like "resonant coax fed antennas are better".

Your example of loops fed with open fedders is right on also. I also have a 277 ft loop fed with open feeders and a (horrors) tuner. This antenna is the equal to the 130ft and is also quieter on rx. I suspect it also has gain on 40mtrs and higher but haven't modeled it in EZNEC yet.

I use the above antennas on 75,40,60,30 mtrs with great success.

Stan K9IUQ





N4SL2007-02-27
RE: Benchmarks
Deer gawd,

Thahank yew fer theese thread.
Aye lauf en lauf eveery day
wen aye reed iit.

Steeve
Reply to a comment by : W9PMZ on 2007-02-22

"antennas are NOT reciprocal in their transmit verses receive performance" Rewriting text books? Most antenna books that I have been privy to read starts the treatment of antennas by making a statement: "In this section we show that the radiation pattern of an antenna is the same whether it is used as a transmitting antenna or a receiving antenna. Reciprocity allows the calculation or measurement of an antenna pattern in either the transmit or receive case." (from Antenna Theory and Design by Stutzman and Thiele, page 40) Propagation at HF makes the antennas properties (height, length, etc) the issue, but the antenna still obeys reciprocity. 73, Carl - W9PMZ
Reply to a comment by : ONAIR on 2007-02-22

Interesting point. So a resonant vertical dipole would then be a lot more efficient than a vertical that you would need to tune?
W4LGH2007-02-27
RE: Benchmarks
Mike W4EF wrote....
For Zl = 100 - j 601 (62:1 VSWR - I was in error before on the VSWR) the delta loss is 8.3dB. Okay that's "absurd". Time to move the matching network out to the antenna feedpoint.

Can you elaborate on your "simple tests". This is a long thread and I couldn't find what you were referring to.
===============
Well, I said I wasn't going to post to this thread anymore, but you asked so here ya go...

Test#1..Install a watt/swr meter -after- your antenna tuner, load your tuner to a good match, then view the meter after the tuner and see whats really happening.

Test#2..Now move the Watt/swr meter out to the antenna and repeat test#1. This will show you your real world actual loss.

Test#3..A little more involved, but a GREAT test, Now take a Field Strength meter, set it on a fixed resonant antenna for a given freq., and measure the RF. Now repeat this on a non-resonant antenna, being matched with you tuner in the shack, and see how much less RF is being radiated.

These are all real world tests done everyday to do proofs on a stations real performance. The same applies to HAM radio as well.

Also I have one multi-band antenna, it uses traps to isolate each freq. section from another. Yes traps have some loss, but it works well, hears good and I get good reports back. However, when I switch to a single band resonant antenna for the same freq. My receive signals are anywhere from 1 to 2 S-units higher on a calibrated S-Meter. That is 6 to 12DB more signal, and does make a difference as to whether you can hear a station or not. The 2 antennas are the same height, configured in the same direction and only 30 apart from each other. On transmit, I have gotten test reports back from 1 to 5 S-Units higher, again a big increase. These tests were done at the same time, as I could switch between antennas. This was also tested when I had a G5RV antenna up in the same place as the trapped antenna, the G5RV being fed with coax and hooked to a tuner in the shack. The results were just about the same.

6 to 12DB of signal loss is NOT acceptable to me, it may be to someone else, but it certainly can make a difference of hearing someone or not. And if you can't hear them, you are certainly not going to talk to them.The G5RV was taken down, the tuner disconnected, and NOT used. The math won't show this amount of loss, to many hidden varibles as I said, actual coaz loss/velocity, and many other factors that just can't be figured in. These were real world tests, and showed GREAT amounts of difference to the better. Try it...you will be amazed!

73, now maybe I am done.
de W4LGH - Alan
http://www.w4lgh.com

Reply to a comment by : W4EF on 2007-02-26

N3OX wrote >> Antenna tuners at the shack end of the coax are the work of a longstanding collaboration between the radio manufacturers and the Lord of Darkness himself and should never be admitted into discussion. << Yes, I just opened up my ATR-30 and I found and pentagram silkscreened on the inside of the top cover. Then I put a crucifix near the tuner and the VSWR went wild. Truly frightening. Mike, W4EF.................
Reply to a comment by : W4EF on 2007-02-26

>>Thats pretty good if you are using Andrew 7/8 hardline, now do the math using RG-8X that 90% of the hams use. The figures shift a bit! And they do make balanced line current meters that will read all sorts of info on your balanced line.<< Good point, Alan. Here are the numbers with the higher dielectric constant Belden RG-8X (the LMR-240 RG-8X has lower loss, but is more expensive): For Zl = 100 - j 117 (5:1 VSWR) the delta loss is 1.0dB. Not bad, but enough to raise an eyebrow. For Zl = 100 - j 601 (62:1 VSWR - I was in error before on the VSWR) the delta loss is 8.3dB. Okay that's "absurd". Time to move the matching network out to the antenna feedpoint. >>Math is good, and you can figure everything in life out with Math, but the math only works in a perfect world<< Well, I don't live in a perfect world, Alan, but I do use math all the time and it works surprisingly well. >>, in a REAL world there are lots of hidden varibles that come into play.<< Yes, of course, that's part of the art of applying analysis to REAL world problems. Because almost all analytical tools are only approximations, doesn't mean you throw them out the window. It just means that you have to be aware of limitations of a particular analytical model when applying it. The transmission line equations used in TLW for calculating loss of mis-matched lines work very well, for instance. >>Do your math, then try my simple tests, and see how close your math comes to the real world. I wouldn't expect you to admit to anything, as it is evident that we all have to much pride to do so. But ya just might learn something. << Well, no, if I am wrong I don't mind eating a little crow (pride and haughty spirit goeth before a fall, and all that). Can you elaborate on your "simple tests". This is a long thread and I couldn't find what you were referring to. 73, Mike W4EF.......................
Reply to a comment by : W4LGH on 2007-02-26

W4EF says: "Expanding on our real world example with the 100 - j 115 antenna feedpoint impedance (5:1 VSWR), if we assume 180 degrees of Andrew 7/8 inch hardline at 1.8 MHz, then the additional system loss incurred when moving the matching network from the antenna feedpoint to the other end of ~74.1 meters of the Andrew hardline will be a whopping 0.154dB!! Hardly "absurd"." ======== Thats pretty good if you are using Andrew 7/8 hardline, now do the math using RG-8X that 90% of the hams use. The figures shift a bit! And they do make balanced line current meters that will read all sorts of info on your balanced line. ========= Math is good, and you can figure everything in life out with Math, but the math only works in a perfect world, in a REAL world there are lots of hidden varibles that come into play. Do your math, then try my simple tests, and see how close your math comes to the real world. I wouldn't expect you to admit to anything, as it is evident that we all have to much pride to do so. But ya just might learn something. ========= As I said you do whatever you want, if you can accept the loss, so be it. The concept of losing something you don't have to is beyond me. Its like throwing your money in the wind. This is it, the last post on this subject for me. You can pick it apart if you like, or you can try my simple tests and see for yourself. Its your call have fun! 73 de W4LGH - Alan http://www.w4lgh.com
Reply to a comment by : N3OX on 2007-02-26

W4EF says: "Expanding on our real world example with the 100 - j 115 antenna feedpoint impedance (5:1 VSWR), if we assume 180 degrees of Andrew 7/8 inch hardline at 1.8 MHz, then the additional system loss incurred when moving the matching network from the antenna feedpoint to the other end of ~74.1 meters of the Andrew hardline will be a whopping 0.154dB!! Hardly "absurd"." Clearly a lie ;-) Mustn't be true. Poppycock! I am shocked at your prevarications! And this from a true ham?! I think not! I'm sorry, but this is a black and white issue on which I must put my foot down. It doesn't matter if you are using just ten feet of four inch O.D. silver plated copper, air dielectric, water cooled, dry nitrogen purged coaxial cable. Antenna tuners at the shack end of the coax are the work of a longstanding collaboration between the radio manufacturers and the Lord of Darkness himself and should never be admitted into discussion. "having the matchbox remote from the antenna feedpoint isn't looking so good anymore." Thank you, that's more like it! Dan (For those without a sense of humor, this is a joke. Not sure it's safe to go disclaimerless around here) He who uses the matching garbage can wins: http://www.n3ox.net/projects/sixtyvert
Reply to a comment by : N3OX on 2007-02-26

And I'd have to take out the "tuning of the system" part to answer 1dB.
Reply to a comment by : N3OX on 2007-02-26

KD2BD says: "What if we increased the length to 1 foot? How about 10 feet? How about 100 feet? At what magic length would you say the use of coaxial line would start to have a detrimental effect on the tuning of the system over an identical length of ladder line? " Exactly! (I'd answer "One dB" except that I don't want to muddy the waters too much... everyone knows a dB isn't a length ;-) ) Dan
Reply to a comment by : KC8QFP on 2007-02-26

Trivial PS: I noticed that in my list of ancient antique confusers, I forgot to mention the Compaq, IBM PC and its clones. The IBM SIG was the place to be! 73, Don
Reply to a comment by : KC8QFP on 2007-02-26

I learned something a long time ago on the Cleveland Freenet (the beginnings of the public access to the internet before there was the WWW). Some of the professors and engineers at CWRU (Case Western Reserve University was home of Cleve Freenet) were the guru's of the computer SIG, and we that had Tandy 1000's - Coco's - Trash 80's, Kaypro's, Apple II's (Freenet originally ran on an Apple ii), even Timex, Commies, Atari, and perhaps the infamous TI99/4 could get on and pick their brains. Same with the law and med students/professors. I learned that these brilliant people DONATED their time for us morons like me. They got a lot of $$$ to teach, lecture, and for any other use of their time. But I got to know some of these guys personally, truely amazing people, and I really appreciated their helping me out with their expertise. I have a lot of respect and admiration for those talanted people that ""elmered"" many a student to have a great career in engineering or whatever. It was sort of like getting some college education for FREE, thanks to their generousity. But I also learn that there were some jerks that did not really appreciate the Freenet, and they did the slamming, flaming, and other typical making an ass of themselves. I was a sysop, and I had to kick some of those jerks off the Freenet because we tried to keep a bar of integrity. My old email was ab064@freenet.org, and aa960 as handicap sigop ID. He are benefitted here on eham with some professional people that freely give their time, and at least I appreciate it. There's always a smartass in the crowd, and we had plenty on Freenet, especially in its chat rooms (I was not interesed in the chat, but heard plenty about it at Freenet get togethers). Thankfully the guru's did not say the hell with it and let the bozo's spoil it for the rest of the decent people. So that's it for soapbox speeches, let's show some grattitude to the guys that we can learn something from. This should not be a battle of nit-witts, but rather compairring notes and sharring of ideas. Now play nice boyzzz! Don
Reply to a comment by : W4LGH on 2007-02-26

K9IUQ wrote...There is a very good reason for this. Professional Installations DONT change frequency. Most ham are frequency agile, that is they don't stay on one frequency like a Professional Installation Does. When you change frequencys like most hams do, the situation changes, hence a tuner in the shack. Hahahahahahahahahaha...now thats about as good of logic as manufactures building ant. tuners into the radios because they are a good thing! Stan you are grabing at straws but you are still sinking into the quicksand. I have changed frequencies on many professional installation, walk out and re-tune the transmatch. The fact the tuner is at the antenna is because it is more effeceint and it actually LOADS the antenna into resonance! YOu're still trying to push, but I am not gonna move. I appologized to you for letting you push me into calling you a F#*KING IDIOT in public, and I sincerely appologize for that, as I should have been bigger than that, but it certainly doesn't change how I feel about you, and you just keep proving it! Maybe one day the light will come on... NOT!!! Modist or not modist, I am proud of my knowledge, and I only share it to try and help others. Do as you wish, its no sweat off my back, and you are probably afraid to try the simple experiments I described earlier as they WILL bust your bubble! Been there done that and have the T-Shirt! Long hard road..and you can keep busting your head along the way. This is it, you are going to believe what you want to, and this ole world is just like BurgerKing...you can have it your way. 73 de W4LGH - ALan http://www.w4lgh.com
Reply to a comment by : K9IUQ on 2007-02-26

Kd2BD says A little bit. :-) ....................................................... Why is it the truly smart hams are so modest and the ones that *think* they are smart and want everyone to know it say I am a BROADCAST ENGINEER (at least 6 times) and put their website in every post so everyone sees how smart they are? I respect you John, but you are too modest. I will help you, here is John's credentials: http://www.qsl.net/kd2bd/index.html Stan K9IUQ
W4EF2007-02-26
RE: Benchmarks
N3OX wrote

>> Antenna tuners at the shack end of the coax are the work of a longstanding collaboration between the radio manufacturers and the Lord of Darkness himself and should never be admitted into discussion. <<

Yes, I just opened up my ATR-30 and I found and pentagram silkscreened on the inside of the top cover. Then I put a crucifix near the tuner and the VSWR went wild. Truly frightening.

Mike, W4EF.................
Reply to a comment by : W4EF on 2007-02-26

>>Thats pretty good if you are using Andrew 7/8 hardline, now do the math using RG-8X that 90% of the hams use. The figures shift a bit! And they do make balanced line current meters that will read all sorts of info on your balanced line.<< Good point, Alan. Here are the numbers with the higher dielectric constant Belden RG-8X (the LMR-240 RG-8X has lower loss, but is more expensive): For Zl = 100 - j 117 (5:1 VSWR) the delta loss is 1.0dB. Not bad, but enough to raise an eyebrow. For Zl = 100 - j 601 (62:1 VSWR - I was in error before on the VSWR) the delta loss is 8.3dB. Okay that's "absurd". Time to move the matching network out to the antenna feedpoint. >>Math is good, and you can figure everything in life out with Math, but the math only works in a perfect world<< Well, I don't live in a perfect world, Alan, but I do use math all the time and it works surprisingly well. >>, in a REAL world there are lots of hidden varibles that come into play.<< Yes, of course, that's part of the art of applying analysis to REAL world problems. Because almost all analytical tools are only approximations, doesn't mean you throw them out the window. It just means that you have to be aware of limitations of a particular analytical model when applying it. The transmission line equations used in TLW for calculating loss of mis-matched lines work very well, for instance. >>Do your math, then try my simple tests, and see how close your math comes to the real world. I wouldn't expect you to admit to anything, as it is evident that we all have to much pride to do so. But ya just might learn something. << Well, no, if I am wrong I don't mind eating a little crow (pride and haughty spirit goeth before a fall, and all that). Can you elaborate on your "simple tests". This is a long thread and I couldn't find what you were referring to. 73, Mike W4EF.......................
Reply to a comment by : W4LGH on 2007-02-26

W4EF says: "Expanding on our real world example with the 100 - j 115 antenna feedpoint impedance (5:1 VSWR), if we assume 180 degrees of Andrew 7/8 inch hardline at 1.8 MHz, then the additional system loss incurred when moving the matching network from the antenna feedpoint to the other end of ~74.1 meters of the Andrew hardline will be a whopping 0.154dB!! Hardly "absurd"." ======== Thats pretty good if you are using Andrew 7/8 hardline, now do the math using RG-8X that 90% of the hams use. The figures shift a bit! And they do make balanced line current meters that will read all sorts of info on your balanced line. ========= Math is good, and you can figure everything in life out with Math, but the math only works in a perfect world, in a REAL world there are lots of hidden varibles that come into play. Do your math, then try my simple tests, and see how close your math comes to the real world. I wouldn't expect you to admit to anything, as it is evident that we all have to much pride to do so. But ya just might learn something. ========= As I said you do whatever you want, if you can accept the loss, so be it. The concept of losing something you don't have to is beyond me. Its like throwing your money in the wind. This is it, the last post on this subject for me. You can pick it apart if you like, or you can try my simple tests and see for yourself. Its your call have fun! 73 de W4LGH - Alan http://www.w4lgh.com
Reply to a comment by : N3OX on 2007-02-26

W4EF says: "Expanding on our real world example with the 100 - j 115 antenna feedpoint impedance (5:1 VSWR), if we assume 180 degrees of Andrew 7/8 inch hardline at 1.8 MHz, then the additional system loss incurred when moving the matching network from the antenna feedpoint to the other end of ~74.1 meters of the Andrew hardline will be a whopping 0.154dB!! Hardly "absurd"." Clearly a lie ;-) Mustn't be true. Poppycock! I am shocked at your prevarications! And this from a true ham?! I think not! I'm sorry, but this is a black and white issue on which I must put my foot down. It doesn't matter if you are using just ten feet of four inch O.D. silver plated copper, air dielectric, water cooled, dry nitrogen purged coaxial cable. Antenna tuners at the shack end of the coax are the work of a longstanding collaboration between the radio manufacturers and the Lord of Darkness himself and should never be admitted into discussion. "having the matchbox remote from the antenna feedpoint isn't looking so good anymore." Thank you, that's more like it! Dan (For those without a sense of humor, this is a joke. Not sure it's safe to go disclaimerless around here) He who uses the matching garbage can wins: http://www.n3ox.net/projects/sixtyvert
Reply to a comment by : N3OX on 2007-02-26

And I'd have to take out the "tuning of the system" part to answer 1dB.
Reply to a comment by : N3OX on 2007-02-26

KD2BD says: "What if we increased the length to 1 foot? How about 10 feet? How about 100 feet? At what magic length would you say the use of coaxial line would start to have a detrimental effect on the tuning of the system over an identical length of ladder line? " Exactly! (I'd answer "One dB" except that I don't want to muddy the waters too much... everyone knows a dB isn't a length ;-) ) Dan
Reply to a comment by : KC8QFP on 2007-02-26

Trivial PS: I noticed that in my list of ancient antique confusers, I forgot to mention the Compaq, IBM PC and its clones. The IBM SIG was the place to be! 73, Don
Reply to a comment by : KC8QFP on 2007-02-26

I learned something a long time ago on the Cleveland Freenet (the beginnings of the public access to the internet before there was the WWW). Some of the professors and engineers at CWRU (Case Western Reserve University was home of Cleve Freenet) were the guru's of the computer SIG, and we that had Tandy 1000's - Coco's - Trash 80's, Kaypro's, Apple II's (Freenet originally ran on an Apple ii), even Timex, Commies, Atari, and perhaps the infamous TI99/4 could get on and pick their brains. Same with the law and med students/professors. I learned that these brilliant people DONATED their time for us morons like me. They got a lot of $$$ to teach, lecture, and for any other use of their time. But I got to know some of these guys personally, truely amazing people, and I really appreciated their helping me out with their expertise. I have a lot of respect and admiration for those talanted people that ""elmered"" many a student to have a great career in engineering or whatever. It was sort of like getting some college education for FREE, thanks to their generousity. But I also learn that there were some jerks that did not really appreciate the Freenet, and they did the slamming, flaming, and other typical making an ass of themselves. I was a sysop, and I had to kick some of those jerks off the Freenet because we tried to keep a bar of integrity. My old email was ab064@freenet.org, and aa960 as handicap sigop ID. He are benefitted here on eham with some professional people that freely give their time, and at least I appreciate it. There's always a smartass in the crowd, and we had plenty on Freenet, especially in its chat rooms (I was not interesed in the chat, but heard plenty about it at Freenet get togethers). Thankfully the guru's did not say the hell with it and let the bozo's spoil it for the rest of the decent people. So that's it for soapbox speeches, let's show some grattitude to the guys that we can learn something from. This should not be a battle of nit-witts, but rather compairring notes and sharring of ideas. Now play nice boyzzz! Don
Reply to a comment by : W4LGH on 2007-02-26

K9IUQ wrote...There is a very good reason for this. Professional Installations DONT change frequency. Most ham are frequency agile, that is they don't stay on one frequency like a Professional Installation Does. When you change frequencys like most hams do, the situation changes, hence a tuner in the shack. Hahahahahahahahahaha...now thats about as good of logic as manufactures building ant. tuners into the radios because they are a good thing! Stan you are grabing at straws but you are still sinking into the quicksand. I have changed frequencies on many professional installation, walk out and re-tune the transmatch. The fact the tuner is at the antenna is because it is more effeceint and it actually LOADS the antenna into resonance! YOu're still trying to push, but I am not gonna move. I appologized to you for letting you push me into calling you a F#*KING IDIOT in public, and I sincerely appologize for that, as I should have been bigger than that, but it certainly doesn't change how I feel about you, and you just keep proving it! Maybe one day the light will come on... NOT!!! Modist or not modist, I am proud of my knowledge, and I only share it to try and help others. Do as you wish, its no sweat off my back, and you are probably afraid to try the simple experiments I described earlier as they WILL bust your bubble! Been there done that and have the T-Shirt! Long hard road..and you can keep busting your head along the way. This is it, you are going to believe what you want to, and this ole world is just like BurgerKing...you can have it your way. 73 de W4LGH - ALan http://www.w4lgh.com
Reply to a comment by : K9IUQ on 2007-02-26

Kd2BD says A little bit. :-) ....................................................... Why is it the truly smart hams are so modest and the ones that *think* they are smart and want everyone to know it say I am a BROADCAST ENGINEER (at least 6 times) and put their website in every post so everyone sees how smart they are? I respect you John, but you are too modest. I will help you, here is John's credentials: http://www.qsl.net/kd2bd/index.html Stan K9IUQ
W4EF2007-02-26
RE: Benchmarks
>>Thats pretty good if you are using Andrew 7/8 hardline, now do the math using RG-8X that 90% of the hams use. The figures shift a bit! And they do make balanced line current meters that will read all sorts of info on your balanced line.<<

Good point, Alan. Here are the numbers with the higher dielectric constant Belden RG-8X (the LMR-240 RG-8X has lower loss, but is more expensive):

For Zl = 100 - j 117 (5:1 VSWR) the delta loss is 1.0dB. Not bad, but enough to raise an eyebrow.

For Zl = 100 - j 601 (62:1 VSWR - I was in error before on the VSWR) the delta loss is 8.3dB. Okay that's "absurd". Time to move the matching network out to the antenna feedpoint.

>>Math is good, and you can figure everything in life out with Math, but the math only works in a perfect world<<

Well, I don't live in a perfect world, Alan, but I do use math all the time and it works surprisingly well.

>>, in a REAL world there are lots of hidden varibles that come into play.<<

Yes, of course, that's part of the art of applying analysis to REAL world problems. Because almost all analytical tools are only approximations, doesn't mean you throw them out the window. It just means that you have to be aware of limitations of a particular analytical model when applying it. The transmission line equations used in TLW for calculating loss of mis-matched lines work very well, for instance.

>>Do your math, then try my simple tests, and see how close your math comes to the real world. I wouldn't expect you to admit to anything, as it is evident that we all have to much pride to do so. But ya just might learn something. <<

Well, no, if I am wrong I don't mind eating a little crow (pride and haughty spirit goeth before a fall, and all that). Can you elaborate on your "simple tests". This is a long thread and I couldn't find what you were referring to.

73, Mike W4EF.......................

Reply to a comment by : W4LGH on 2007-02-26

W4EF says: "Expanding on our real world example with the 100 - j 115 antenna feedpoint impedance (5:1 VSWR), if we assume 180 degrees of Andrew 7/8 inch hardline at 1.8 MHz, then the additional system loss incurred when moving the matching network from the antenna feedpoint to the other end of ~74.1 meters of the Andrew hardline will be a whopping 0.154dB!! Hardly "absurd"." ======== Thats pretty good if you are using Andrew 7/8 hardline, now do the math using RG-8X that 90% of the hams use. The figures shift a bit! And they do make balanced line current meters that will read all sorts of info on your balanced line. ========= Math is good, and you can figure everything in life out with Math, but the math only works in a perfect world, in a REAL world there are lots of hidden varibles that come into play. Do your math, then try my simple tests, and see how close your math comes to the real world. I wouldn't expect you to admit to anything, as it is evident that we all have to much pride to do so. But ya just might learn something. ========= As I said you do whatever you want, if you can accept the loss, so be it. The concept of losing something you don't have to is beyond me. Its like throwing your money in the wind. This is it, the last post on this subject for me. You can pick it apart if you like, or you can try my simple tests and see for yourself. Its your call have fun! 73 de W4LGH - Alan http://www.w4lgh.com
Reply to a comment by : N3OX on 2007-02-26

W4EF says: "Expanding on our real world example with the 100 - j 115 antenna feedpoint impedance (5:1 VSWR), if we assume 180 degrees of Andrew 7/8 inch hardline at 1.8 MHz, then the additional system loss incurred when moving the matching network from the antenna feedpoint to the other end of ~74.1 meters of the Andrew hardline will be a whopping 0.154dB!! Hardly "absurd"." Clearly a lie ;-) Mustn't be true. Poppycock! I am shocked at your prevarications! And this from a true ham?! I think not! I'm sorry, but this is a black and white issue on which I must put my foot down. It doesn't matter if you are using just ten feet of four inch O.D. silver plated copper, air dielectric, water cooled, dry nitrogen purged coaxial cable. Antenna tuners at the shack end of the coax are the work of a longstanding collaboration between the radio manufacturers and the Lord of Darkness himself and should never be admitted into discussion. "having the matchbox remote from the antenna feedpoint isn't looking so good anymore." Thank you, that's more like it! Dan (For those without a sense of humor, this is a joke. Not sure it's safe to go disclaimerless around here) He who uses the matching garbage can wins: http://www.n3ox.net/projects/sixtyvert
Reply to a comment by : N3OX on 2007-02-26

And I'd have to take out the "tuning of the system" part to answer 1dB.
Reply to a comment by : N3OX on 2007-02-26

KD2BD says: "What if we increased the length to 1 foot? How about 10 feet? How about 100 feet? At what magic length would you say the use of coaxial line would start to have a detrimental effect on the tuning of the system over an identical length of ladder line? " Exactly! (I'd answer "One dB" except that I don't want to muddy the waters too much... everyone knows a dB isn't a length ;-) ) Dan
Reply to a comment by : KC8QFP on 2007-02-26

Trivial PS: I noticed that in my list of ancient antique confusers, I forgot to mention the Compaq, IBM PC and its clones. The IBM SIG was the place to be! 73, Don
Reply to a comment by : KC8QFP on 2007-02-26

I learned something a long time ago on the Cleveland Freenet (the beginnings of the public access to the internet before there was the WWW). Some of the professors and engineers at CWRU (Case Western Reserve University was home of Cleve Freenet) were the guru's of the computer SIG, and we that had Tandy 1000's - Coco's - Trash 80's, Kaypro's, Apple II's (Freenet originally ran on an Apple ii), even Timex, Commies, Atari, and perhaps the infamous TI99/4 could get on and pick their brains. Same with the law and med students/professors. I learned that these brilliant people DONATED their time for us morons like me. They got a lot of $$$ to teach, lecture, and for any other use of their time. But I got to know some of these guys personally, truely amazing people, and I really appreciated their helping me out with their expertise. I have a lot of respect and admiration for those talanted people that ""elmered"" many a student to have a great career in engineering or whatever. It was sort of like getting some college education for FREE, thanks to their generousity. But I also learn that there were some jerks that did not really appreciate the Freenet, and they did the slamming, flaming, and other typical making an ass of themselves. I was a sysop, and I had to kick some of those jerks off the Freenet because we tried to keep a bar of integrity. My old email was ab064@freenet.org, and aa960 as handicap sigop ID. He are benefitted here on eham with some professional people that freely give their time, and at least I appreciate it. There's always a smartass in the crowd, and we had plenty on Freenet, especially in its chat rooms (I was not interesed in the chat, but heard plenty about it at Freenet get togethers). Thankfully the guru's did not say the hell with it and let the bozo's spoil it for the rest of the decent people. So that's it for soapbox speeches, let's show some grattitude to the guys that we can learn something from. This should not be a battle of nit-witts, but rather compairring notes and sharring of ideas. Now play nice boyzzz! Don
Reply to a comment by : W4LGH on 2007-02-26

K9IUQ wrote...There is a very good reason for this. Professional Installations DONT change frequency. Most ham are frequency agile, that is they don't stay on one frequency like a Professional Installation Does. When you change frequencys like most hams do, the situation changes, hence a tuner in the shack. Hahahahahahahahahaha...now thats about as good of logic as manufactures building ant. tuners into the radios because they are a good thing! Stan you are grabing at straws but you are still sinking into the quicksand. I have changed frequencies on many professional installation, walk out and re-tune the transmatch. The fact the tuner is at the antenna is because it is more effeceint and it actually LOADS the antenna into resonance! YOu're still trying to push, but I am not gonna move. I appologized to you for letting you push me into calling you a F#*KING IDIOT in public, and I sincerely appologize for that, as I should have been bigger than that, but it certainly doesn't change how I feel about you, and you just keep proving it! Maybe one day the light will come on... NOT!!! Modist or not modist, I am proud of my knowledge, and I only share it to try and help others. Do as you wish, its no sweat off my back, and you are probably afraid to try the simple experiments I described earlier as they WILL bust your bubble! Been there done that and have the T-Shirt! Long hard road..and you can keep busting your head along the way. This is it, you are going to believe what you want to, and this ole world is just like BurgerKing...you can have it your way. 73 de W4LGH - ALan http://www.w4lgh.com
Reply to a comment by : K9IUQ on 2007-02-26

Kd2BD says A little bit. :-) ....................................................... Why is it the truly smart hams are so modest and the ones that *think* they are smart and want everyone to know it say I am a BROADCAST ENGINEER (at least 6 times) and put their website in every post so everyone sees how smart they are? I respect you John, but you are too modest. I will help you, here is John's credentials: http://www.qsl.net/kd2bd/index.html Stan K9IUQ
N3OX2007-02-26
RE: Benchmarks
W4LGH says: "Thats pretty good if you are using Andrew 7/8 hardline, now do the math using RG-8X that 90% of the hams use."

Now there's something we can agree on! Doesn't require any nastiness, either.

"Math is good, and you can figure everything in life out with Math, but the math only works in a perfect world, in a REAL world there are lots of hidden varibles that come into play."

I would say that the model is only as good as your knowledge its limitations and the range of applicability, not simply that "there are a lot of hidden variables"

Oversimplification is called OVERsimplification for a reason.

Dan
Reply to a comment by : W4LGH on 2007-02-26

W4EF says: "Expanding on our real world example with the 100 - j 115 antenna feedpoint impedance (5:1 VSWR), if we assume 180 degrees of Andrew 7/8 inch hardline at 1.8 MHz, then the additional system loss incurred when moving the matching network from the antenna feedpoint to the other end of ~74.1 meters of the Andrew hardline will be a whopping 0.154dB!! Hardly "absurd"." ======== Thats pretty good if you are using Andrew 7/8 hardline, now do the math using RG-8X that 90% of the hams use. The figures shift a bit! And they do make balanced line current meters that will read all sorts of info on your balanced line. ========= Math is good, and you can figure everything in life out with Math, but the math only works in a perfect world, in a REAL world there are lots of hidden varibles that come into play. Do your math, then try my simple tests, and see how close your math comes to the real world. I wouldn't expect you to admit to anything, as it is evident that we all have to much pride to do so. But ya just might learn something. ========= As I said you do whatever you want, if you can accept the loss, so be it. The concept of losing something you don't have to is beyond me. Its like throwing your money in the wind. This is it, the last post on this subject for me. You can pick it apart if you like, or you can try my simple tests and see for yourself. Its your call have fun! 73 de W4LGH - Alan http://www.w4lgh.com
Reply to a comment by : N3OX on 2007-02-26

W4EF says: "Expanding on our real world example with the 100 - j 115 antenna feedpoint impedance (5:1 VSWR), if we assume 180 degrees of Andrew 7/8 inch hardline at 1.8 MHz, then the additional system loss incurred when moving the matching network from the antenna feedpoint to the other end of ~74.1 meters of the Andrew hardline will be a whopping 0.154dB!! Hardly "absurd"." Clearly a lie ;-) Mustn't be true. Poppycock! I am shocked at your prevarications! And this from a true ham?! I think not! I'm sorry, but this is a black and white issue on which I must put my foot down. It doesn't matter if you are using just ten feet of four inch O.D. silver plated copper, air dielectric, water cooled, dry nitrogen purged coaxial cable. Antenna tuners at the shack end of the coax are the work of a longstanding collaboration between the radio manufacturers and the Lord of Darkness himself and should never be admitted into discussion. "having the matchbox remote from the antenna feedpoint isn't looking so good anymore." Thank you, that's more like it! Dan (For those without a sense of humor, this is a joke. Not sure it's safe to go disclaimerless around here) He who uses the matching garbage can wins: http://www.n3ox.net/projects/sixtyvert
Reply to a comment by : N3OX on 2007-02-26

And I'd have to take out the "tuning of the system" part to answer 1dB.
Reply to a comment by : N3OX on 2007-02-26

KD2BD says: "What if we increased the length to 1 foot? How about 10 feet? How about 100 feet? At what magic length would you say the use of coaxial line would start to have a detrimental effect on the tuning of the system over an identical length of ladder line? " Exactly! (I'd answer "One dB" except that I don't want to muddy the waters too much... everyone knows a dB isn't a length ;-) ) Dan
Reply to a comment by : KC8QFP on 2007-02-26

Trivial PS: I noticed that in my list of ancient antique confusers, I forgot to mention the Compaq, IBM PC and its clones. The IBM SIG was the place to be! 73, Don
Reply to a comment by : KC8QFP on 2007-02-26

I learned something a long time ago on the Cleveland Freenet (the beginnings of the public access to the internet before there was the WWW). Some of the professors and engineers at CWRU (Case Western Reserve University was home of Cleve Freenet) were the guru's of the computer SIG, and we that had Tandy 1000's - Coco's - Trash 80's, Kaypro's, Apple II's (Freenet originally ran on an Apple ii), even Timex, Commies, Atari, and perhaps the infamous TI99/4 could get on and pick their brains. Same with the law and med students/professors. I learned that these brilliant people DONATED their time for us morons like me. They got a lot of $$$ to teach, lecture, and for any other use of their time. But I got to know some of these guys personally, truely amazing people, and I really appreciated their helping me out with their expertise. I have a lot of respect and admiration for those talanted people that ""elmered"" many a student to have a great career in engineering or whatever. It was sort of like getting some college education for FREE, thanks to their generousity. But I also learn that there were some jerks that did not really appreciate the Freenet, and they did the slamming, flaming, and other typical making an ass of themselves. I was a sysop, and I had to kick some of those jerks off the Freenet because we tried to keep a bar of integrity. My old email was ab064@freenet.org, and aa960 as handicap sigop ID. He are benefitted here on eham with some professional people that freely give their time, and at least I appreciate it. There's always a smartass in the crowd, and we had plenty on Freenet, especially in its chat rooms (I was not interesed in the chat, but heard plenty about it at Freenet get togethers). Thankfully the guru's did not say the hell with it and let the bozo's spoil it for the rest of the decent people. So that's it for soapbox speeches, let's show some grattitude to the guys that we can learn something from. This should not be a battle of nit-witts, but rather compairring notes and sharring of ideas. Now play nice boyzzz! Don
Reply to a comment by : W4LGH on 2007-02-26

K9IUQ wrote...There is a very good reason for this. Professional Installations DONT change frequency. Most ham are frequency agile, that is they don't stay on one frequency like a Professional Installation Does. When you change frequencys like most hams do, the situation changes, hence a tuner in the shack. Hahahahahahahahahaha...now thats about as good of logic as manufactures building ant. tuners into the radios because they are a good thing! Stan you are grabing at straws but you are still sinking into the quicksand. I have changed frequencies on many professional installation, walk out and re-tune the transmatch. The fact the tuner is at the antenna is because it is more effeceint and it actually LOADS the antenna into resonance! YOu're still trying to push, but I am not gonna move. I appologized to you for letting you push me into calling you a F#*KING IDIOT in public, and I sincerely appologize for that, as I should have been bigger than that, but it certainly doesn't change how I feel about you, and you just keep proving it! Maybe one day the light will come on... NOT!!! Modist or not modist, I am proud of my knowledge, and I only share it to try and help others. Do as you wish, its no sweat off my back, and you are probably afraid to try the simple experiments I described earlier as they WILL bust your bubble! Been there done that and have the T-Shirt! Long hard road..and you can keep busting your head along the way. This is it, you are going to believe what you want to, and this ole world is just like BurgerKing...you can have it your way. 73 de W4LGH - ALan http://www.w4lgh.com
Reply to a comment by : K9IUQ on 2007-02-26

Kd2BD says A little bit. :-) ....................................................... Why is it the truly smart hams are so modest and the ones that *think* they are smart and want everyone to know it say I am a BROADCAST ENGINEER (at least 6 times) and put their website in every post so everyone sees how smart they are? I respect you John, but you are too modest. I will help you, here is John's credentials: http://www.qsl.net/kd2bd/index.html Stan K9IUQ
W4LGH2007-02-26
RE: Benchmarks
W4EF says: "Expanding on our real world example with the 100 - j 115 antenna feedpoint impedance (5:1 VSWR), if we assume 180 degrees of Andrew 7/8 inch hardline at 1.8 MHz, then the additional system loss incurred when moving the matching network from the antenna feedpoint to the other end of ~74.1 meters of the Andrew hardline will be a whopping 0.154dB!! Hardly "absurd"."
========
Thats pretty good if you are using Andrew 7/8 hardline, now do the math using RG-8X that 90% of the hams use. The figures shift a bit! And they do make balanced line current meters that will read all sorts of info on your balanced line.
=========
Math is good, and you can figure everything in life out with Math, but the math only works in a perfect world, in a REAL world there are lots of hidden varibles that come into play. Do your math, then try my simple tests, and see how close your math comes to the real world. I wouldn't expect you to admit to anything, as it is evident that we all have to much pride to do so. But ya just might learn something.
=========
As I said you do whatever you want, if you can accept the loss, so be it. The concept of losing something you don't have to is beyond me. Its like throwing your money in the wind.

This is it, the last post on this subject for me. You can pick it apart if you like, or you can try my simple tests and see for yourself. Its your call have fun!

73 de W4LGH - Alan
http://www.w4lgh.com

Reply to a comment by : N3OX on 2007-02-26

W4EF says: "Expanding on our real world example with the 100 - j 115 antenna feedpoint impedance (5:1 VSWR), if we assume 180 degrees of Andrew 7/8 inch hardline at 1.8 MHz, then the additional system loss incurred when moving the matching network from the antenna feedpoint to the other end of ~74.1 meters of the Andrew hardline will be a whopping 0.154dB!! Hardly "absurd"." Clearly a lie ;-) Mustn't be true. Poppycock! I am shocked at your prevarications! And this from a true ham?! I think not! I'm sorry, but this is a black and white issue on which I must put my foot down. It doesn't matter if you are using just ten feet of four inch O.D. silver plated copper, air dielectric, water cooled, dry nitrogen purged coaxial cable. Antenna tuners at the shack end of the coax are the work of a longstanding collaboration between the radio manufacturers and the Lord of Darkness himself and should never be admitted into discussion. "having the matchbox remote from the antenna feedpoint isn't looking so good anymore." Thank you, that's more like it! Dan (For those without a sense of humor, this is a joke. Not sure it's safe to go disclaimerless around here) He who uses the matching garbage can wins: http://www.n3ox.net/projects/sixtyvert
Reply to a comment by : N3OX on 2007-02-26

And I'd have to take out the "tuning of the system" part to answer 1dB.
Reply to a comment by : N3OX on 2007-02-26

KD2BD says: "What if we increased the length to 1 foot? How about 10 feet? How about 100 feet? At what magic length would you say the use of coaxial line would start to have a detrimental effect on the tuning of the system over an identical length of ladder line? " Exactly! (I'd answer "One dB" except that I don't want to muddy the waters too much... everyone knows a dB isn't a length ;-) ) Dan
Reply to a comment by : KC8QFP on 2007-02-26

Trivial PS: I noticed that in my list of ancient antique confusers, I forgot to mention the Compaq, IBM PC and its clones. The IBM SIG was the place to be! 73, Don
Reply to a comment by : KC8QFP on 2007-02-26

I learned something a long time ago on the Cleveland Freenet (the beginnings of the public access to the internet before there was the WWW). Some of the professors and engineers at CWRU (Case Western Reserve University was home of Cleve Freenet) were the guru's of the computer SIG, and we that had Tandy 1000's - Coco's - Trash 80's, Kaypro's, Apple II's (Freenet originally ran on an Apple ii), even Timex, Commies, Atari, and perhaps the infamous TI99/4 could get on and pick their brains. Same with the law and med students/professors. I learned that these brilliant people DONATED their time for us morons like me. They got a lot of $$$ to teach, lecture, and for any other use of their time. But I got to know some of these guys personally, truely amazing people, and I really appreciated their helping me out with their expertise. I have a lot of respect and admiration for those talanted people that ""elmered"" many a student to have a great career in engineering or whatever. It was sort of like getting some college education for FREE, thanks to their generousity. But I also learn that there were some jerks that did not really appreciate the Freenet, and they did the slamming, flaming, and other typical making an ass of themselves. I was a sysop, and I had to kick some of those jerks off the Freenet because we tried to keep a bar of integrity. My old email was ab064@freenet.org, and aa960 as handicap sigop ID. He are benefitted here on eham with some professional people that freely give their time, and at least I appreciate it. There's always a smartass in the crowd, and we had plenty on Freenet, especially in its chat rooms (I was not interesed in the chat, but heard plenty about it at Freenet get togethers). Thankfully the guru's did not say the hell with it and let the bozo's spoil it for the rest of the decent people. So that's it for soapbox speeches, let's show some grattitude to the guys that we can learn something from. This should not be a battle of nit-witts, but rather compairring notes and sharring of ideas. Now play nice boyzzz! Don
Reply to a comment by : W4LGH on 2007-02-26

K9IUQ wrote...There is a very good reason for this. Professional Installations DONT change frequency. Most ham are frequency agile, that is they don't stay on one frequency like a Professional Installation Does. When you change frequencys like most hams do, the situation changes, hence a tuner in the shack. Hahahahahahahahahaha...now thats about as good of logic as manufactures building ant. tuners into the radios because they are a good thing! Stan you are grabing at straws but you are still sinking into the quicksand. I have changed frequencies on many professional installation, walk out and re-tune the transmatch. The fact the tuner is at the antenna is because it is more effeceint and it actually LOADS the antenna into resonance! YOu're still trying to push, but I am not gonna move. I appologized to you for letting you push me into calling you a F#*KING IDIOT in public, and I sincerely appologize for that, as I should have been bigger than that, but it certainly doesn't change how I feel about you, and you just keep proving it! Maybe one day the light will come on... NOT!!! Modist or not modist, I am proud of my knowledge, and I only share it to try and help others. Do as you wish, its no sweat off my back, and you are probably afraid to try the simple experiments I described earlier as they WILL bust your bubble! Been there done that and have the T-Shirt! Long hard road..and you can keep busting your head along the way. This is it, you are going to believe what you want to, and this ole world is just like BurgerKing...you can have it your way. 73 de W4LGH - ALan http://www.w4lgh.com
Reply to a comment by : K9IUQ on 2007-02-26

Kd2BD says A little bit. :-) ....................................................... Why is it the truly smart hams are so modest and the ones that *think* they are smart and want everyone to know it say I am a BROADCAST ENGINEER (at least 6 times) and put their website in every post so everyone sees how smart they are? I respect you John, but you are too modest. I will help you, here is John's credentials: http://www.qsl.net/kd2bd/index.html Stan K9IUQ
N3OX2007-02-26
RE: Benchmarks
W4EF says: "Expanding on our real world example with the 100 - j 115 antenna feedpoint impedance (5:1 VSWR), if we assume 180 degrees of Andrew 7/8 inch hardline at 1.8 MHz, then the additional system loss incurred when moving the matching network from the antenna feedpoint to the other end of ~74.1 meters of the Andrew hardline will be a whopping 0.154dB!! Hardly "absurd"."

Clearly a lie ;-) Mustn't be true. Poppycock! I am shocked at your prevarications! And this from a true ham?! I think not!

I'm sorry, but this is a black and white issue on which I must put my foot down. It doesn't matter if you are using just ten feet of four inch O.D. silver plated copper, air dielectric, water cooled, dry nitrogen purged coaxial cable. Antenna tuners at the shack end of the coax are the work of a longstanding collaboration between the radio manufacturers and the Lord of Darkness himself and should never be admitted into discussion.

"having the matchbox remote from the antenna feedpoint isn't looking so good anymore."

Thank you, that's more like it!

Dan

(For those without a sense of humor, this is a joke. Not sure it's safe to go disclaimerless around here)

He who uses the matching garbage can wins:

http://www.n3ox.net/projects/sixtyvert
Reply to a comment by : N3OX on 2007-02-26

And I'd have to take out the "tuning of the system" part to answer 1dB.
Reply to a comment by : N3OX on 2007-02-26

KD2BD says: "What if we increased the length to 1 foot? How about 10 feet? How about 100 feet? At what magic length would you say the use of coaxial line would start to have a detrimental effect on the tuning of the system over an identical length of ladder line? " Exactly! (I'd answer "One dB" except that I don't want to muddy the waters too much... everyone knows a dB isn't a length ;-) ) Dan
Reply to a comment by : KC8QFP on 2007-02-26

Trivial PS: I noticed that in my list of ancient antique confusers, I forgot to mention the Compaq, IBM PC and its clones. The IBM SIG was the place to be! 73, Don
Reply to a comment by : KC8QFP on 2007-02-26

I learned something a long time ago on the Cleveland Freenet (the beginnings of the public access to the internet before there was the WWW). Some of the professors and engineers at CWRU (Case Western Reserve University was home of Cleve Freenet) were the guru's of the computer SIG, and we that had Tandy 1000's - Coco's - Trash 80's, Kaypro's, Apple II's (Freenet originally ran on an Apple ii), even Timex, Commies, Atari, and perhaps the infamous TI99/4 could get on and pick their brains. Same with the law and med students/professors. I learned that these brilliant people DONATED their time for us morons like me. They got a lot of $$$ to teach, lecture, and for any other use of their time. But I got to know some of these guys personally, truely amazing people, and I really appreciated their helping me out with their expertise. I have a lot of respect and admiration for those talanted people that ""elmered"" many a student to have a great career in engineering or whatever. It was sort of like getting some college education for FREE, thanks to their generousity. But I also learn that there were some jerks that did not really appreciate the Freenet, and they did the slamming, flaming, and other typical making an ass of themselves. I was a sysop, and I had to kick some of those jerks off the Freenet because we tried to keep a bar of integrity. My old email was ab064@freenet.org, and aa960 as handicap sigop ID. He are benefitted here on eham with some professional people that freely give their time, and at least I appreciate it. There's always a smartass in the crowd, and we had plenty on Freenet, especially in its chat rooms (I was not interesed in the chat, but heard plenty about it at Freenet get togethers). Thankfully the guru's did not say the hell with it and let the bozo's spoil it for the rest of the decent people. So that's it for soapbox speeches, let's show some grattitude to the guys that we can learn something from. This should not be a battle of nit-witts, but rather compairring notes and sharring of ideas. Now play nice boyzzz! Don
Reply to a comment by : W4LGH on 2007-02-26

K9IUQ wrote...There is a very good reason for this. Professional Installations DONT change frequency. Most ham are frequency agile, that is they don't stay on one frequency like a Professional Installation Does. When you change frequencys like most hams do, the situation changes, hence a tuner in the shack. Hahahahahahahahahaha...now thats about as good of logic as manufactures building ant. tuners into the radios because they are a good thing! Stan you are grabing at straws but you are still sinking into the quicksand. I have changed frequencies on many professional installation, walk out and re-tune the transmatch. The fact the tuner is at the antenna is because it is more effeceint and it actually LOADS the antenna into resonance! YOu're still trying to push, but I am not gonna move. I appologized to you for letting you push me into calling you a F#*KING IDIOT in public, and I sincerely appologize for that, as I should have been bigger than that, but it certainly doesn't change how I feel about you, and you just keep proving it! Maybe one day the light will come on... NOT!!! Modist or not modist, I am proud of my knowledge, and I only share it to try and help others. Do as you wish, its no sweat off my back, and you are probably afraid to try the simple experiments I described earlier as they WILL bust your bubble! Been there done that and have the T-Shirt! Long hard road..and you can keep busting your head along the way. This is it, you are going to believe what you want to, and this ole world is just like BurgerKing...you can have it your way. 73 de W4LGH - ALan http://www.w4lgh.com
Reply to a comment by : K9IUQ on 2007-02-26

Kd2BD says A little bit. :-) ....................................................... Why is it the truly smart hams are so modest and the ones that *think* they are smart and want everyone to know it say I am a BROADCAST ENGINEER (at least 6 times) and put their website in every post so everyone sees how smart they are? I respect you John, but you are too modest. I will help you, here is John's credentials: http://www.qsl.net/kd2bd/index.html Stan K9IUQ
N3OX2007-02-26
RE: Benchmarks
And I'd have to take out the "tuning of the system" part to answer 1dB.
Reply to a comment by : N3OX on 2007-02-26

KD2BD says: "What if we increased the length to 1 foot? How about 10 feet? How about 100 feet? At what magic length would you say the use of coaxial line would start to have a detrimental effect on the tuning of the system over an identical length of ladder line? " Exactly! (I'd answer "One dB" except that I don't want to muddy the waters too much... everyone knows a dB isn't a length ;-) ) Dan
Reply to a comment by : KC8QFP on 2007-02-26

Trivial PS: I noticed that in my list of ancient antique confusers, I forgot to mention the Compaq, IBM PC and its clones. The IBM SIG was the place to be! 73, Don
Reply to a comment by : KC8QFP on 2007-02-26

I learned something a long time ago on the Cleveland Freenet (the beginnings of the public access to the internet before there was the WWW). Some of the professors and engineers at CWRU (Case Western Reserve University was home of Cleve Freenet) were the guru's of the computer SIG, and we that had Tandy 1000's - Coco's - Trash 80's, Kaypro's, Apple II's (Freenet originally ran on an Apple ii), even Timex, Commies, Atari, and perhaps the infamous TI99/4 could get on and pick their brains. Same with the law and med students/professors. I learned that these brilliant people DONATED their time for us morons like me. They got a lot of $$$ to teach, lecture, and for any other use of their time. But I got to know some of these guys personally, truely amazing people, and I really appreciated their helping me out with their expertise. I have a lot of respect and admiration for those talanted people that ""elmered"" many a student to have a great career in engineering or whatever. It was sort of like getting some college education for FREE, thanks to their generousity. But I also learn that there were some jerks that did not really appreciate the Freenet, and they did the slamming, flaming, and other typical making an ass of themselves. I was a sysop, and I had to kick some of those jerks off the Freenet because we tried to keep a bar of integrity. My old email was ab064@freenet.org, and aa960 as handicap sigop ID. He are benefitted here on eham with some professional people that freely give their time, and at least I appreciate it. There's always a smartass in the crowd, and we had plenty on Freenet, especially in its chat rooms (I was not interesed in the chat, but heard plenty about it at Freenet get togethers). Thankfully the guru's did not say the hell with it and let the bozo's spoil it for the rest of the decent people. So that's it for soapbox speeches, let's show some grattitude to the guys that we can learn something from. This should not be a battle of nit-witts, but rather compairring notes and sharring of ideas. Now play nice boyzzz! Don
Reply to a comment by : W4LGH on 2007-02-26

K9IUQ wrote...There is a very good reason for this. Professional Installations DONT change frequency. Most ham are frequency agile, that is they don't stay on one frequency like a Professional Installation Does. When you change frequencys like most hams do, the situation changes, hence a tuner in the shack. Hahahahahahahahahaha...now thats about as good of logic as manufactures building ant. tuners into the radios because they are a good thing! Stan you are grabing at straws but you are still sinking into the quicksand. I have changed frequencies on many professional installation, walk out and re-tune the transmatch. The fact the tuner is at the antenna is because it is more effeceint and it actually LOADS the antenna into resonance! YOu're still trying to push, but I am not gonna move. I appologized to you for letting you push me into calling you a F#*KING IDIOT in public, and I sincerely appologize for that, as I should have been bigger than that, but it certainly doesn't change how I feel about you, and you just keep proving it! Maybe one day the light will come on... NOT!!! Modist or not modist, I am proud of my knowledge, and I only share it to try and help others. Do as you wish, its no sweat off my back, and you are probably afraid to try the simple experiments I described earlier as they WILL bust your bubble! Been there done that and have the T-Shirt! Long hard road..and you can keep busting your head along the way. This is it, you are going to believe what you want to, and this ole world is just like BurgerKing...you can have it your way. 73 de W4LGH - ALan http://www.w4lgh.com
Reply to a comment by : K9IUQ on 2007-02-26

Kd2BD says A little bit. :-) ....................................................... Why is it the truly smart hams are so modest and the ones that *think* they are smart and want everyone to know it say I am a BROADCAST ENGINEER (at least 6 times) and put their website in every post so everyone sees how smart they are? I respect you John, but you are too modest. I will help you, here is John's credentials: http://www.qsl.net/kd2bd/index.html Stan K9IUQ
N3OX2007-02-26
RE: Benchmarks
KD2BD says:

"What if we increased the length to 1 foot? How about 10 feet? How about 100 feet? At what magic length would you say the use of coaxial line would start to have a detrimental effect on the tuning of the system over an identical length of ladder line? "

Exactly!

(I'd answer "One dB" except that I don't want to muddy the waters too much... everyone knows a dB isn't a length ;-) )

Dan
Reply to a comment by : KC8QFP on 2007-02-26

Trivial PS: I noticed that in my list of ancient antique confusers, I forgot to mention the Compaq, IBM PC and its clones. The IBM SIG was the place to be! 73, Don
Reply to a comment by : KC8QFP on 2007-02-26

I learned something a long time ago on the Cleveland Freenet (the beginnings of the public access to the internet before there was the WWW). Some of the professors and engineers at CWRU (Case Western Reserve University was home of Cleve Freenet) were the guru's of the computer SIG, and we that had Tandy 1000's - Coco's - Trash 80's, Kaypro's, Apple II's (Freenet originally ran on an Apple ii), even Timex, Commies, Atari, and perhaps the infamous TI99/4 could get on and pick their brains. Same with the law and med students/professors. I learned that these brilliant people DONATED their time for us morons like me. They got a lot of $$$ to teach, lecture, and for any other use of their time. But I got to know some of these guys personally, truely amazing people, and I really appreciated their helping me out with their expertise. I have a lot of respect and admiration for those talanted people that ""elmered"" many a student to have a great career in engineering or whatever. It was sort of like getting some college education for FREE, thanks to their generousity. But I also learn that there were some jerks that did not really appreciate the Freenet, and they did the slamming, flaming, and other typical making an ass of themselves. I was a sysop, and I had to kick some of those jerks off the Freenet because we tried to keep a bar of integrity. My old email was ab064@freenet.org, and aa960 as handicap sigop ID. He are benefitted here on eham with some professional people that freely give their time, and at least I appreciate it. There's always a smartass in the crowd, and we had plenty on Freenet, especially in its chat rooms (I was not interesed in the chat, but heard plenty about it at Freenet get togethers). Thankfully the guru's did not say the hell with it and let the bozo's spoil it for the rest of the decent people. So that's it for soapbox speeches, let's show some grattitude to the guys that we can learn something from. This should not be a battle of nit-witts, but rather compairring notes and sharring of ideas. Now play nice boyzzz! Don
Reply to a comment by : W4LGH on 2007-02-26

K9IUQ wrote...There is a very good reason for this. Professional Installations DONT change frequency. Most ham are frequency agile, that is they don't stay on one frequency like a Professional Installation Does. When you change frequencys like most hams do, the situation changes, hence a tuner in the shack. Hahahahahahahahahaha...now thats about as good of logic as manufactures building ant. tuners into the radios because they are a good thing! Stan you are grabing at straws but you are still sinking into the quicksand. I have changed frequencies on many professional installation, walk out and re-tune the transmatch. The fact the tuner is at the antenna is because it is more effeceint and it actually LOADS the antenna into resonance! YOu're still trying to push, but I am not gonna move. I appologized to you for letting you push me into calling you a F#*KING IDIOT in public, and I sincerely appologize for that, as I should have been bigger than that, but it certainly doesn't change how I feel about you, and you just keep proving it! Maybe one day the light will come on... NOT!!! Modist or not modist, I am proud of my knowledge, and I only share it to try and help others. Do as you wish, its no sweat off my back, and you are probably afraid to try the simple experiments I described earlier as they WILL bust your bubble! Been there done that and have the T-Shirt! Long hard road..and you can keep busting your head along the way. This is it, you are going to believe what you want to, and this ole world is just like BurgerKing...you can have it your way. 73 de W4LGH - ALan http://www.w4lgh.com
Reply to a comment by : K9IUQ on 2007-02-26

Kd2BD says A little bit. :-) ....................................................... Why is it the truly smart hams are so modest and the ones that *think* they are smart and want everyone to know it say I am a BROADCAST ENGINEER (at least 6 times) and put their website in every post so everyone sees how smart they are? I respect you John, but you are too modest. I will help you, here is John's credentials: http://www.qsl.net/kd2bd/index.html Stan K9IUQ
KC8QFP2007-02-26
RE: Benchmarks
Trivial PS: I noticed that in my list of ancient antique confusers, I forgot to mention the Compaq, IBM PC and its clones. The IBM SIG was the place to be!

73, Don
Reply to a comment by : KC8QFP on 2007-02-26

I learned something a long time ago on the Cleveland Freenet (the beginnings of the public access to the internet before there was the WWW). Some of the professors and engineers at CWRU (Case Western Reserve University was home of Cleve Freenet) were the guru's of the computer SIG, and we that had Tandy 1000's - Coco's - Trash 80's, Kaypro's, Apple II's (Freenet originally ran on an Apple ii), even Timex, Commies, Atari, and perhaps the infamous TI99/4 could get on and pick their brains. Same with the law and med students/professors. I learned that these brilliant people DONATED their time for us morons like me. They got a lot of $$$ to teach, lecture, and for any other use of their time. But I got to know some of these guys personally, truely amazing people, and I really appreciated their helping me out with their expertise. I have a lot of respect and admiration for those talanted people that ""elmered"" many a student to have a great career in engineering or whatever. It was sort of like getting some college education for FREE, thanks to their generousity. But I also learn that there were some jerks that did not really appreciate the Freenet, and they did the slamming, flaming, and other typical making an ass of themselves. I was a sysop, and I had to kick some of those jerks off the Freenet because we tried to keep a bar of integrity. My old email was ab064@freenet.org, and aa960 as handicap sigop ID. He are benefitted here on eham with some professional people that freely give their time, and at least I appreciate it. There's always a smartass in the crowd, and we had plenty on Freenet, especially in its chat rooms (I was not interesed in the chat, but heard plenty about it at Freenet get togethers). Thankfully the guru's did not say the hell with it and let the bozo's spoil it for the rest of the decent people. So that's it for soapbox speeches, let's show some grattitude to the guys that we can learn something from. This should not be a battle of nit-witts, but rather compairring notes and sharring of ideas. Now play nice boyzzz! Don
Reply to a comment by : W4LGH on 2007-02-26

K9IUQ wrote...There is a very good reason for this. Professional Installations DONT change frequency. Most ham are frequency agile, that is they don't stay on one frequency like a Professional Installation Does. When you change frequencys like most hams do, the situation changes, hence a tuner in the shack. Hahahahahahahahahaha...now thats about as good of logic as manufactures building ant. tuners into the radios because they are a good thing! Stan you are grabing at straws but you are still sinking into the quicksand. I have changed frequencies on many professional installation, walk out and re-tune the transmatch. The fact the tuner is at the antenna is because it is more effeceint and it actually LOADS the antenna into resonance! YOu're still trying to push, but I am not gonna move. I appologized to you for letting you push me into calling you a F#*KING IDIOT in public, and I sincerely appologize for that, as I should have been bigger than that, but it certainly doesn't change how I feel about you, and you just keep proving it! Maybe one day the light will come on... NOT!!! Modist or not modist, I am proud of my knowledge, and I only share it to try and help others. Do as you wish, its no sweat off my back, and you are probably afraid to try the simple experiments I described earlier as they WILL bust your bubble! Been there done that and have the T-Shirt! Long hard road..and you can keep busting your head along the way. This is it, you are going to believe what you want to, and this ole world is just like BurgerKing...you can have it your way. 73 de W4LGH - ALan http://www.w4lgh.com
Reply to a comment by : K9IUQ on 2007-02-26

Kd2BD says A little bit. :-) ....................................................... Why is it the truly smart hams are so modest and the ones that *think* they are smart and want everyone to know it say I am a BROADCAST ENGINEER (at least 6 times) and put their website in every post so everyone sees how smart they are? I respect you John, but you are too modest. I will help you, here is John's credentials: http://www.qsl.net/kd2bd/index.html Stan K9IUQ
KC8QFP2007-02-26
RE: Benchmarks
I learned something a long time ago on the Cleveland Freenet (the beginnings of the public access to the internet before there was the WWW). Some of the professors and engineers at CWRU (Case Western Reserve University was home of Cleve Freenet) were the guru's of the computer SIG, and we that had Tandy 1000's - Coco's - Trash 80's, Kaypro's, Apple II's (Freenet originally ran on an Apple ii), even Timex, Commies, Atari, and perhaps the infamous TI99/4 could get on and pick their brains. Same with the law and med students/professors. I learned that these brilliant people DONATED their time for us morons like me. They got a lot of $$$ to teach, lecture, and for any other use of their time. But I got to know some of these guys personally, truely amazing people, and I really appreciated their helping me out with their expertise. I have a lot of respect and admiration for those talanted people that ""elmered"" many a student to have a great career in engineering or whatever. It was sort of like getting some college education for FREE, thanks to their generousity. But I also learn that there were some jerks that did not really appreciate the Freenet, and they did the slamming, flaming, and other typical making an ass of themselves. I was a sysop, and I had to kick some of those jerks off the Freenet because we tried to keep a bar of integrity. My old email was ab064@freenet.org, and aa960 as handicap sigop ID. He are benefitted here on eham with some professional people that freely give their time, and at least I appreciate it. There's always a smartass in the crowd, and we had plenty on Freenet, especially in its chat rooms (I was not interesed in the chat, but heard plenty about it at Freenet get togethers). Thankfully the guru's did not say the hell with it and let the bozo's spoil it for the rest of the decent people. So that's it for soapbox speeches, let's show some grattitude to the guys that we can learn something from. This should not be a battle of nit-witts, but rather compairring notes and sharring of ideas.

Now play nice boyzzz! Don
Reply to a comment by : W4LGH on 2007-02-26

K9IUQ wrote...There is a very good reason for this. Professional Installations DONT change frequency. Most ham are frequency agile, that is they don't stay on one frequency like a Professional Installation Does. When you change frequencys like most hams do, the situation changes, hence a tuner in the shack. Hahahahahahahahahaha...now thats about as good of logic as manufactures building ant. tuners into the radios because they are a good thing! Stan you are grabing at straws but you are still sinking into the quicksand. I have changed frequencies on many professional installation, walk out and re-tune the transmatch. The fact the tuner is at the antenna is because it is more effeceint and it actually LOADS the antenna into resonance! YOu're still trying to push, but I am not gonna move. I appologized to you for letting you push me into calling you a F#*KING IDIOT in public, and I sincerely appologize for that, as I should have been bigger than that, but it certainly doesn't change how I feel about you, and you just keep proving it! Maybe one day the light will come on... NOT!!! Modist or not modist, I am proud of my knowledge, and I only share it to try and help others. Do as you wish, its no sweat off my back, and you are probably afraid to try the simple experiments I described earlier as they WILL bust your bubble! Been there done that and have the T-Shirt! Long hard road..and you can keep busting your head along the way. This is it, you are going to believe what you want to, and this ole world is just like BurgerKing...you can have it your way. 73 de W4LGH - ALan http://www.w4lgh.com
Reply to a comment by : K9IUQ on 2007-02-26

Kd2BD says A little bit. :-) ....................................................... Why is it the truly smart hams are so modest and the ones that *think* they are smart and want everyone to know it say I am a BROADCAST ENGINEER (at least 6 times) and put their website in every post so everyone sees how smart they are? I respect you John, but you are too modest. I will help you, here is John's credentials: http://www.qsl.net/kd2bd/index.html Stan K9IUQ
W4EF2007-02-26
RE: Benchmarks
W4LGH wrote:

>> The fact the tuner is at the antenna is because it is more effeceint <<

Grammer and spelling aside, I agree that the above is true in general. In the case of a modest mismatch, the penalty for moving the matching network to the shack end of a coax run is small. The convenience of doing this may outway the small loss penalty (that is my situation at my own QTH). In the case of a BC station where the electricity for the transmitter can cost many thousands of dollars per month, and you aren't retuning every 2 minutes as a ham radio contester or DXer might, but rather every few months (if even that often), leaving the matching network at the base of the antenna is likely the better choice.

<<and it actually LOADS the antenna into resonance! <<

When you put a matching network at the feedpoint of an antenna, you are doing nothing more than transforming the input impedance of the antenna from something undesireable (100 - j 117 for instance) into something that is compatible with the transmitter and or feedline (50 + j 0 ). You can call that impedance transformation process "ANTENNA LOADING" when it occurs at the antenna feedpoint and pretend that this is a different physical process than the process that occurs in the matching network when a 180 degree length of coaxial cable is installed between that same matching network and that same antenna feedpoint, but doing so is just arguing semantics. The matchbox is stupid, it can't tell the difference. In either case, the matchbox see's ~ 100 - j117 at its output terminals, and in both cases, it transforms this impedance from 100 - j117 into 50 + j0. The current distribution on the antenna is the same in both cases, and the only difference in gain will be due to the additional mismatch loss in the 180 degree length of coaxial cable.

Expanding on our real world example with the 100 - j 115 antenna feedpoint impedance (5:1 VSWR), if we assume 180 degrees of Andrew 7/8 inch hardline at 1.8 MHz, then the additional system loss incurred when moving the matching network from the antenna feedpoint to the other end of ~74.1 meters of the Andrew hardline will be a whopping 0.154dB!! Hardly "absurd".

Now if we repeat the same experiment using an antenna feedpoint impedance of 100 - j 604 (40:1 VSWR), the additional loss incurred by moving the matchbox to the other side of the 74.1 meter length of Andrew 7/8" hardline is 2.6dB. This is not the end of the world from a ham's perspective, but it's enough extra loss that the tradeoff of having the matchbox remote from the antenna feedpoint isn't looking so good anymore.

73, Mike W4EF..........................
Reply to a comment by : N4KC on 2007-02-26

We love our antennas, don't we? This topic has--I think--more responses than anything since the "no-code" threads. Good news: we obviously recognize the importance of our antenna systems, and we have some very intelligent people contributing to the debate. Bad news: we got a bit childish there for a while! Maybe I can sum up some things here that I see as truisms. Others may consider them heresy. At any rate, if responses continue as above, I'm confident we'll all learn, even if we don't change our points of view. Truism #1: 100 watts of RF energy at the output of a transmitter is 100 watts, regardless of what impedance or the nature of the load it will soon encounter at that point. Truism #2: Most of today's transmitters will not operate properly if that impedance deviates too much from 50 ohms. Truism #3: We are better to speak of an antenna SYSTEM. An "antenna" does no work unless it is hooked to some kind of feedline to transfer energy to and from the antenna, or is, in the case of a long wire, hooked to a matching unit, a receiver, and/or a transmitter. Still, there is much more to a SYSTEM than antenna and feedline...matching devices (if any), other objects in the near field, the dirt or liquid beneath it, nearby terrain and manmade structures, and--in the broadest interpretation--the atmosphere of the earth. Truism #4: All antenna systems are compromises. Few of us live over a salt marsh. Many are not lucky enough to hang resonant wire antennas for every possible frequency we would want to operate, especially at today's copper prices! And forget getting a 160-meter antenna a half-wavelength off the ground! Truism #5: If an operator wishes to use an antenna on more than one band, it must either be designed to be extremely broadbanded or has to be fed in such a way that the resultant standing waves created by the lack of resonance are not lost due to loss in the feedline. Truism #5A: a very broadbanded antenna often has too many other faults to make it practical. Truism #5B: coax--regardless of the quality and promised loss figures--is rarely a better choice for low-loss feedline than air- or plastic-dielectric balanced line. Truism #6: If coax feedline is employed, its loss becomes problematic as frequency increases, as its length goes up, and, in some cases, as its diameter is reduced. On the other hand, coax is easy to work with, can be run near metal objects with little coupling, and has convenient screw-on fittings that make strong attachment to other devices. However, if the coax feedline is used with a non-resonant antenna (and the antenna is more and more non-resonant as the operating frequency deviates from the aerial's design frequency) standing waves that course up and down the cable become victims of that loss. It is dissipated in the form of heat, not radiated from the antenna in the form of useful RF, flung in the direction of a DX station. Truism #7: As a compromise, it is perfectly all right to use a feedline matching device (sometimes referred to as an "antenna tuner") to match a transmitter's 50 ohm output to the feedline, whatever type it might be. The operator acknowledges that there is some loss of energy in the matching device itself, and some of his RF will be lost in the feedline. Almost any conductor has loss. But that's what often happens in a compromise. You do the best you can and you move on. The DX station will never hear you if you don't quit worrying about how much RF you are losing and go ahead and put the key down! Truism #7A: It is NOT idiotic to use an antenna system matching device to allow a transmitter to work into an otherwise mismatched load, but the operator should be aware of what he or she is sacrificing for the convenience of using coax and a non-resonant antenna. In many cases (the 75/80-meter band, for example), being able to match the load usefully at the nether reaches of the band are much better accomplished with a "tuner" than with one or two more antennas in the sky. Truism #7B: Most operators will not be happy with the results if they attempt to use RG-8X coax to run several hundred feet to a proposed multi-band antenna that has been cut much too short for some of the bands on which he or she intends to operate. The coax and the tuner will likely become quite warm, depending on the amount of power run to the system. And signal reports may be disappointing. Truism #8: Hams knew 75 years ago that low loss "open-wire" balanced feedlines had many desireable benefits. Convenience and ease of routing and handling aside, long runs of such feedline carried more RF energy to distant antennas. When coax came along, it was clear the newer stuff had advantages. Having lower loss than the tried-and-true was not one of them. Truism #8A: Balanced air- or plastic-dielectric feedlines can be used with multiband wire antennas to make them possible to use on many amateur bands, simply because the SWR loss in the feedline is much, much less than with coax. Truism #8B: There is still the necessity to match a wide range of reactance presented by a multi-band antenna to the transmitter output and the receiver input. That is another valid use of a matching device, whether it is a tuner in the radio, a tuner on the table next to the radio, a tuner somewhere in the feedline, a tuner at the antenna feedpoint, or some other combination of variable inductive and capacitive reactance that the operator can manipulate somehow. Truism #8C: Balanced feedline has come back into vogue, in my opinion, primarily because many of us wanted an antenna system that could be used on all 10 HF ham bands...and that we could use to switch quickly from one band to another with as little compromise as possible. I don't have the option to put up 10 "resonant" antennas, and a 10-band fan dipole would present something of a navigation hazard to the songbirds (not to mention the neighborhood kids) in my area. Truism #9: There is absolutely a place in any ham shack for a matching device ("tuner"). Even if all the operator's antennas are cut to resonance and fed with low loss coax, there may be frequencies the operator desires to transmit or receive at which the antenna is no longer comfortably near resonance. Truism #10: A wire dipole, cut to at least a half wavelength long on the lowest proposed operating frequency, and fed with ladder/window/open wire feedline, properly matched with a good matching device that may include a current balun, is a very good antenna system for both transmitting and receiving. The higher above ground it is hung, the better (with a few exceptions that affect angle of radiation). It is at least the equal of a resonant dipole, fed with good quality coax, that is being operated on its "resonant" frequency. It is certainly better than that coax-fed dipole once the operator ventures off that resonant spot in the spectrum. Truism #10A: Other wire antennas, such as the horizontal full- or two-wavelength loop, fed with low loss balanced line, are actually better than that coax-fed dipole...including on many, many frequencies at which the balanced antenna is decidedly non-resonant. These are some of the things I believe to be true. Anybody have any quibbles? 73, Don N4KC www.donkeith.com www.donkeith.com/n4kc.htm (under construction)
Reply to a comment by : K9IUQ on 2007-02-26

Kd2BD says Are we to believe these impedance matching networks, that are present in nearly EVERY transmitter, are FOOLING the tubes and/or transistors they contain because they transform impedances and terminate in an SO-239? Of course not. Should it make a difference whether the impedance matching network is contained inside or outside of the rig's cabinet? Of course not. 73, de John, KD2BD ....................................................... John, WOW. What an excellent explanation. I havent looked you up in QRZ.com yet but I bet you have plenty of background to back up what you just said. When intelligent hams speak with such clarity as you just did , less smart hams (like myself) take notice. Stan K9IUQ
KD2BD2007-02-26
RE: Benchmarks
W4LGH wrote:

> KD2BD wrote~~~ If we were to take a half-wave dipole that has been
> properly cut for resonance at a particular operating frequency, we would
> expect to see a feed point impedance of about 60 ohms resistive.
> ============
>
>
> Actually it is closer to 72ohms @ the feed point and not 60.

If we are talking about an infinitely thin dipole in free space, then YES, I would agree that in theory, 72 ohms is correct.

When using the size of conductors we typically use in real-world antenna installations, the impedance becomes closer to 60 ohms. When we include dipole "end effects", the proximity of the ground and other surrounding objects, it will likely vary even more (maybe 50 to 100 ohms).

The exact value is moot. It's still a very small number compared to 600 ohms and will produce a very high VSWR condition on the open wire line.

If the electrical length doesn't happen to be a multiple of a quarter wavelength at our operating frequency, the impedance at the near end of the feed line will be REACTIVE and will require an LC matching network in the shack TO RE-ESTABLISH SYSTEM RESONANCE (even though the dipole was initially resonant) and transform the impedance to 50 ohms resistive so it to accept power from the transmitter.

That is no different than what happens with a coaxial feed arrangement and a non-resonant dipole.

The characteristic impedance of a transmission line is given as the square root of L over C. Whether the impedance of the line is 50 ohms, 300 ohms, 450 ohms, or 600 ohms doesn't matter. The distributed L and C constants change, but the action and behavior of the line remains exactly the same.

> The pi network on your tubes were designed to bring the 3000ohm output of
> the tube down to 50ohms to match the coax. Now if you have some weird
> impedance on your coax, you will not get it to tune. It is there to match
> the output to a known impedance of an antenna feed line.

The tuning and loading controls allowed for some "wiggle room" with respect to impedance matching. If you could "dip and load" to the proper level of plate current, the actual impedance of the antenna and/or transmission line really didn't matter (within reasonable bounds, of course).

> And you would be better off loss wise to feed the tube with a higher
> impedance open line, but the tradeoffs aren't worth it.

Transformers convert and match impedances for maximum power transfer to help maintain high system efficiency. Would you prefer electrical utility companies stop using power transformers?

> When you feed an antenna with an open line such as 300 or 450ohm line,
> you have effectively moved the antenna tuner out the the antenna. As
> you tune your tuner for the best possible match, you are tuning out all
> the reactance and impedance differences from the back of the tuner, so
> this includes the balanced feed line into the antenna. When you do this
> with coax, you are only tuning out the reactance at the END of the COAX,
> the mis-matches still apply along the coax and the antenna.

The mismatch still exists under a balanced feed system as well, and may be significantly worse than coaxial feed if the antenna feedpoint impedance is low.

Just because Bird Electronic Corporation doesn't make a directional wattmeter for 600 ohm balanced line doesn't mean balanced lines don't undergo high VSWR conditions.

Why do you feel coax behaves so much differently than balanced line?

What if we connected a dipole to a tuner through just 1 inch of RG/8? Would you still feel the tuner was just "tuning the coax", not the antenna?

What if we increased the length to 1 foot? How about 10 feet? How about 100 feet? At what magic length would you say the use of coaxial line would start to have a detrimental effect on the tuning of the system over an identical length of ladder line?

And why?


73, de John, KD2BD
Reply to a comment by : W4LGH on 2007-02-26

KD2DB wrote~~~ If we were to take a half-wave dipole that has been properly cut for resonance at a particular operating frequency, we would expect to see a feed point impedance of about 60 ohms resistive. ============ Actually it is closer to 72ohms @ the feed point and not 60. The pi network on your tubes were designed to bring the 3000ohm output of the tube down to 50ohms to match the coax. Now if you have some weird impedance on your coax, you will not get it to tune. It is there to match the output to a known impedance of an antenna feed line. And you would be better off loss wise to feed the tube with a higher impedance open line, but the tradeoffs aren't worth it. When you feed an antenna with an open line such as 300 or 450ohm line, you have effectively moved the antenna tuner out the the antenna. As you tune your tuner for the best possible match, you are tuning out all the reactance and impedance differences from the back of the tuner, so this includes the balanced feed line into the antenna. When you do this with coax, you are only tuning out the reactance at the END of the COAX, the mis-matches still apply along the coax and the antenna. All of you do as you wish, and think as you wish, this is why on EVERY professional installation, the transmatch/tuner will be out at the antenna and NOT in the transmitter room, unless the antenna is being fed with open line. Do whatever, I am tired of trying to explain this, as it is evident some of you just do get it. The loss may be low, or the loss may be HIGH, why have anymore loss than you should have. 1db can make a difference in being heard or not. Try the experiments I described earlier...you just see the light then. Especially the one where you completely disconnect your coax from your antenna, then tune your antenna tuner to a perfect match! See who you can talk to?? Also try this on your tube amp, remove the coax and see if you can load it up. Watch out for sparks! Load up your coax with your tuner to you see 100watts, then go out to the antenna and insert the watt meter and see what you have. Very easy things to do, but do as you wish, as I am done trying to turn the lights on, as you can lead a horse to water, but you can't make him drink. 73 de W4LGH - ALan http://www.w4lgh.com
Reply to a comment by : KD2BD on 2007-02-26

W4LGH wrote on February 26, 2007: > I have said all along that you can tune your antenna somewhat > using open feed line, as it becomes part of the antenna. It becomes "part of the antenna"? How so? What it is about coaxial line that keeps it "separate" from the antenna? If we were to take a half-wave dipole that has been properly cut for resonance at a particular operating frequency, we would expect to see a feed point impedance of about 60 ohms resistive. If we were to attach a length of 600 ohm balanced line to the antenna and bring it into the shack, the VSWR will be 10:1 throughout the entire length of the line. Unless the electrical length of the line just happens to be a multiple of a quarter wavelength at our operating frequency, the impedance we would see in the shack would be REACTIVE. In other words, it would be indicative of an antenna system that is NOT resonant at the design frequency, and would be no different in this regard than if we had cut the dipole too long or too short and fed it with coax. If we wish to properly terminate a 50 ohm transmitter into either one of these loads, we must "tune out" the reactance using an LC network (such as a tuner) TO ESTABLISH SYSTEM RESONANCE, and then transform the resistive component of the impedance to 50 ohms. And there's nothing wrong with that. > I still say that hooking un-balanced (coax) to your tuner is a JOKE. It is no more of a joke than using a Pi Network in a tube rig to match a 3000 ohm plate impedance to a 50 ohm unbalanced (coaxial) line. It is no more of a joke than using a broadband transformer in a solid state rig to match a 7 ohm collector impedance to a 50 ohm unbalanced (coaxial) line. Are we to believe these impedance matching networks, that are present in nearly EVERY transmitter, are FOOLING the tubes and/or transistors they contain because they transform impedances and terminate in an SO-239? Of course not. Should it make a difference whether the impedance matching network is contained inside or outside of the rig's cabinet? Of course not. 73, de John, KD2BD
Reply to a comment by : W4LGH on 2007-02-26

Stan K9IUQ wrote~~ And AL says "And to Stan, I appologize to you, for letting you push me to my limits." K9IUQ says there may be hope for you Al, the first step is admitting you can be wrong..... ================= Never said I was wrong, I said I apologize to you for letting you push me to far. I won't budge anymore. And M. Walter Maxwell did his studies back in the 1930's, he joined RCA in 1949, in 1958 he bcame a charter member of RCA's Astro-Electronics Center, and 1960 to his retirement, he was at the RCA Space Center in Princeton NJ. I know who he is, and what he said. And if you look at his current setup he uses an 80m dipole up at 65' fed with OPEN LINE (450ohm) hooked to a Balanced Trans-Match to tune it. He also has a 7 band folded unipole, again fed with OPEN LEAD (450ohm) to a 3KW BALANCED Trans-Match. Now I wonder why the "Expert" didn't bring in coax to his tuners/trans-match. He also states that he 80M dipole is RESONANT on 80M, and his Unipole is RESONANT on 160M. I have said all along that you can tune your antenna somewhat using open feed line, as it becomes part of the antenna. I still say that hooking un-balanced (coax) to your tuner is a JOKE...and it seems the expert does too as actions always speak louder than words. I said from the begining, and I still say, a RESONANT antenna will work better on the frequency it is resonant for than one that is non-resonant. The key words here are "BETTER" as I never said it wouldn't work, that RESONANT was better, and you CAN'T tune your antenna with a tuner in your shack hooked to COAX!. You can tune an Antenna, you can Tune a Guitar, BUT, you CAN NOT TUNAFISH! 73..Now go play radio! W4LGH - Alan http://www.w4lgh.com
Reply to a comment by : WB2WIK on 2007-02-26

>Benchmarks Reply by K9IUQ on February 26, 2007 Mail this to a friend! W4LGH Says "Also keep in mind that when all these experts like "Maxwell" was doing his thing, it was accepted that transmittions above 30 mhz were useless. And we all know how WRONG that was!" ..................................................... The Reflections book written by Maxwell was originally was written as articles in QST magazine during the 1970's. The original Reflections book which I own was published by the ARRL in 1991. It has been updated in Reflections II and III. Make no Mistake, Maxwell was and still is considered an expert.< ::Right you are. Walt Maxwell is still with us and his writings are recent and relevant. The *other* Maxwell, James Clerk Maxwell, whose work helped defined electromagnetic theory forever, died in 1879 before the first wireless radio contact had ever been made... WB2WIK/6
Reply to a comment by : K9IUQ on 2007-02-26

W4LGH Says "Also keep in mind that when all these experts like "Maxwell" was doing his thing, it was accepted that transmittions above 30 mhz were useless. And we all know how WRONG that was!" ..................................................... The Reflections book written by Maxwell was originally was written as articles in QST magazine during the 1970's. The original Reflections book which I own was published by the ARRL in 1991. It has been updated in Reflections II and III. Make no Mistake, Maxwell was and still is considered an expert. And AL says "And to Stan, I appologize to you, for letting you push me to my limits." K9IUQ says there may be hope for you Al, the first step is admitting you can be wrong..... Stan K9IUQ
K9IUQ2007-02-26
Benchmarks
W4LGH continues entertaining: Modist or not modist, I am proud of my knowledge,

.....................................................
Al my friend, the next time you want to appear to be intelligent in a public forum either get a spell checker or stop drinking.

Stan K9IUQ
K9IUQ2007-02-26
Benchmarks
These are some of the things I believe to be true. Anybody have any quibbles?

73,

Don N4KC

........................................................
Don
Thanks for sorting the wheat from the chaff, the BS from the Truth. GREAT JOB.If only EVERY newbie ham will only read your post and forget all the others.. You should have posted this a few days ago and we wouldn't have had to read all the wife's tales and Myths that still persist.

Stan K9IUQ
N4KC2007-02-26
RE: Benchmarks
We love our antennas, don't we? This topic has--I think--more responses than anything since the "no-code" threads.

Good news: we obviously recognize the importance of our antenna systems, and we have some very intelligent people contributing to the debate.

Bad news: we got a bit childish there for a while!

Maybe I can sum up some things here that I see as truisms. Others may consider them heresy. At any rate, if responses continue as above, I'm confident we'll all learn, even if we don't change our points of view.

Truism #1: 100 watts of RF energy at the output of a transmitter is 100 watts, regardless of what impedance or the nature of the load it will soon encounter at that point.

Truism #2: Most of today's transmitters will not operate properly if that impedance deviates too much from 50 ohms.

Truism #3: We are better to speak of an antenna SYSTEM. An "antenna" does no work unless it is hooked to some kind of feedline to transfer energy to and from the antenna, or is, in the case of a long wire, hooked to a matching unit, a receiver, and/or a transmitter. Still, there is much more to a SYSTEM than antenna and feedline...matching devices (if any), other objects in the near field, the dirt or liquid beneath it, nearby terrain and manmade structures, and--in the broadest interpretation--the atmosphere of the earth.

Truism #4: All antenna systems are compromises. Few of us live over a salt marsh. Many are not lucky enough to hang resonant wire antennas for every possible frequency we would want to operate, especially at today's copper prices! And forget getting a 160-meter antenna a half-wavelength off the ground!

Truism #5: If an operator wishes to use an antenna on more than one band, it must either be designed to be extremely broadbanded or has to be fed in such a way that the resultant standing waves created by the lack of resonance are not lost due to loss in the feedline.
Truism #5A: a very broadbanded antenna often has too many other faults to make it practical.
Truism #5B: coax--regardless of the quality and promised loss figures--is rarely a better choice for low-loss feedline than air- or plastic-dielectric balanced line.

Truism #6: If coax feedline is employed, its loss becomes problematic as frequency increases, as its length goes up, and, in some cases, as its diameter is reduced. On the other hand, coax is easy to work with, can be run near metal objects with little coupling, and has convenient screw-on fittings that make strong attachment to other devices. However, if the coax feedline is used with a non-resonant antenna (and the antenna is more and more non-resonant as the operating frequency deviates from the aerial's design frequency) standing waves that course up and down the cable become victims of that loss. It is dissipated in the form of heat, not radiated from the antenna in the form of useful RF, flung in the direction of a DX station.

Truism #7: As a compromise, it is perfectly all right to use a feedline matching device (sometimes referred to as an "antenna tuner") to match a transmitter's 50 ohm output to the feedline, whatever type it might be. The operator acknowledges that there is some loss of energy in the matching device itself, and some of his RF will be lost in the feedline. Almost any conductor has loss. But that's what often happens in a compromise. You do the best you can and you move on. The DX station will never hear you if you don't quit worrying about how much RF you are losing and go ahead and put the key down!
Truism #7A: It is NOT idiotic to use an antenna system matching device to allow a transmitter to work into an otherwise mismatched load, but the operator should be aware of what he or she is sacrificing for the convenience of using coax and a non-resonant antenna. In many cases (the 75/80-meter band, for example), being able to match the load usefully at the nether reaches of the band are much better accomplished with a "tuner" than with one or two more antennas in the sky.
Truism #7B: Most operators will not be happy with the results if they attempt to use RG-8X coax to run several hundred feet to a proposed multi-band antenna that has been cut much too short for some of the bands on which he or she intends to operate. The coax and the tuner will likely become quite warm, depending on the amount of power run to the system. And signal reports may be disappointing.

Truism #8: Hams knew 75 years ago that low loss "open-wire" balanced feedlines had many desireable benefits. Convenience and ease of routing and handling aside, long runs of such feedline carried more RF energy to distant antennas. When coax came along, it was clear the newer stuff had advantages. Having lower loss than the tried-and-true was not one of them.
Truism #8A: Balanced air- or plastic-dielectric feedlines can be used with multiband wire antennas to make them possible to use on many amateur bands, simply because the SWR loss in the feedline is much, much less than with coax.
Truism #8B: There is still the necessity to match a wide range of reactance presented by a multi-band antenna to the transmitter output and the receiver input. That is another valid use of a matching device, whether it is a tuner in the radio, a tuner on the table next to the radio, a tuner somewhere in the feedline, a tuner at the antenna feedpoint, or some other combination of variable inductive and capacitive reactance that the operator can manipulate somehow.
Truism #8C: Balanced feedline has come back into vogue, in my opinion, primarily because many of us wanted an antenna system that could be used on all 10 HF ham bands...and that we could use to switch quickly from one band to another with as little compromise as possible. I don't have the option to put up 10 "resonant" antennas, and a 10-band fan dipole would present something of a navigation hazard to the songbirds (not to mention the neighborhood kids) in my area.

Truism #9: There is absolutely a place in any ham shack for a matching device ("tuner"). Even if all the operator's antennas are cut to resonance and fed with low loss coax, there may be frequencies the operator desires to transmit or receive at which the antenna is no longer comfortably near resonance.

Truism #10: A wire dipole, cut to at least a half wavelength long on the lowest proposed operating frequency, and fed with ladder/window/open wire feedline, properly matched with a good matching device that may include a current balun, is a very good antenna system for both transmitting and receiving. The higher above ground it is hung, the better (with a few exceptions that affect angle of radiation). It is at least the equal of a resonant dipole, fed with good quality coax, that is being operated on its "resonant" frequency. It is certainly better than that coax-fed dipole once the operator ventures off that resonant spot in the spectrum.

Truism #10A: Other wire antennas, such as the horizontal full- or two-wavelength loop, fed with low loss balanced line, are actually better than that coax-fed dipole...including on many, many frequencies at which the balanced antenna is decidedly non-resonant.

These are some of the things I believe to be true. Anybody have any quibbles?

73,

Don N4KC
www.donkeith.com
www.donkeith.com/n4kc.htm (under construction)
Reply to a comment by : K9IUQ on 2007-02-26

Kd2BD says Are we to believe these impedance matching networks, that are present in nearly EVERY transmitter, are FOOLING the tubes and/or transistors they contain because they transform impedances and terminate in an SO-239? Of course not. Should it make a difference whether the impedance matching network is contained inside or outside of the rig's cabinet? Of course not. 73, de John, KD2BD ....................................................... John, WOW. What an excellent explanation. I havent looked you up in QRZ.com yet but I bet you have plenty of background to back up what you just said. When intelligent hams speak with such clarity as you just did , less smart hams (like myself) take notice. Stan K9IUQ
W4LGH2007-02-26
RE: Benchmarks
K9IUQ wrote...There is a very good reason for this. Professional Installations DONT change frequency. Most ham are frequency agile, that is they don't stay on one frequency like a Professional Installation Does. When you change frequencys like most hams do, the situation changes, hence a tuner in the shack.

Hahahahahahahahahaha...now thats about as good of logic as manufactures building ant. tuners into the radios because they are a good thing! Stan you are grabing at straws but you are still sinking into the quicksand. I have changed frequencies on many professional installation, walk out and re-tune the transmatch. The fact the tuner is at the antenna is because it is more effeceint and it actually LOADS the antenna into resonance!

YOu're still trying to push, but I am not gonna move. I appologized to you for letting you push me into calling you a F#*KING IDIOT in public, and I sincerely appologize for that, as I should have been bigger than that, but it certainly doesn't change how I feel about you, and you just keep proving it!

Maybe one day the light will come on... NOT!!!
Modist or not modist, I am proud of my knowledge, and I only share it to try and help others. Do as you wish, its no sweat off my back, and you are probably afraid to try the simple experiments I described earlier as they WILL bust your bubble! Been there done that and have the T-Shirt! Long hard road..and you can keep busting your head along the way.

This is it, you are going to believe what you want to, and this ole world is just like BurgerKing...you can have it your way.

73 de W4LGH - ALan
http://www.w4lgh.com
Reply to a comment by : K9IUQ on 2007-02-26

Kd2BD says A little bit. :-) ....................................................... Why is it the truly smart hams are so modest and the ones that *think* they are smart and want everyone to know it say I am a BROADCAST ENGINEER (at least 6 times) and put their website in every post so everyone sees how smart they are? I respect you John, but you are too modest. I will help you, here is John's credentials: http://www.qsl.net/kd2bd/index.html Stan K9IUQ
K9IUQ2007-02-26
Benchmarks
Kd2BD says A little bit. :-)

.......................................................
Why is it the truly smart hams are so modest and the ones that *think* they are smart and want everyone to know it say I am a BROADCAST ENGINEER (at least 6 times) and put their website in every post so everyone sees how smart they are?

I respect you John, but you are too modest. I will help you, here is John's credentials:

http://www.qsl.net/kd2bd/index.html

Stan K9IUQ
N3OX2007-02-26
RE: Benchmarks
W4LGH maintains: "I said from the begining, and I still say, a RESONANT antenna will work better on the frequency it is resonant for than one that is non-resonant. The key words here are "BETTER" as I never said it wouldn't work, that RESONANT was better. "

Gawd.
Reply to a comment by : KD2BD on 2007-02-26

Stan, K9IUQ wrote: > John, WOW. What an excellent explanation. I havent > looked you up in QRZ.com yet but I bet you have > plenty of background to back up what you just said. A little bit. :-) > When intelligent hams speak with such clarity as you > just did , less smart hams (like myself) take notice. > > Stan K9IUQ Thank you very much for the compliment and your kind words, Stan. I hope my little explanation helped you to see through some of the "Old Wives Tales" that are so prevalent wherever Hams gather and chat. 73, de John, KD2BD
Reply to a comment by : K9IUQ on 2007-02-26

Kd2BD says Are we to believe these impedance matching networks, that are present in nearly EVERY transmitter, are FOOLING the tubes and/or transistors they contain because they transform impedances and terminate in an SO-239? Of course not. Should it make a difference whether the impedance matching network is contained inside or outside of the rig's cabinet? Of course not. 73, de John, KD2BD ....................................................... John, WOW. What an excellent explanation. I havent looked you up in QRZ.com yet but I bet you have plenty of background to back up what you just said. When intelligent hams speak with such clarity as you just did , less smart hams (like myself) take notice. Stan K9IUQ
K9IUQ2007-02-26
Benchmarks
W4LGH gives up and says: I am done trying to turn the lights on,

.....................................................
Al PLEASE don't leave the thread, you have been VERY entertaining.

ROTFL

K9IUQ
KD2BD2007-02-26
RE: Benchmarks
Stan, K9IUQ wrote:

> John, WOW. What an excellent explanation. I havent
> looked you up in QRZ.com yet but I bet you have
> plenty of background to back up what you just said.

A little bit. :-)

> When intelligent hams speak with such clarity as you
> just did , less smart hams (like myself) take notice.
>
> Stan K9IUQ

Thank you very much for the compliment and your kind words, Stan.

I hope my little explanation helped you to see through some of the "Old Wives Tales" that are so prevalent wherever Hams gather and chat.


73, de John, KD2BD
Reply to a comment by : K9IUQ on 2007-02-26

Kd2BD says Are we to believe these impedance matching networks, that are present in nearly EVERY transmitter, are FOOLING the tubes and/or transistors they contain because they transform impedances and terminate in an SO-239? Of course not. Should it make a difference whether the impedance matching network is contained inside or outside of the rig's cabinet? Of course not. 73, de John, KD2BD ....................................................... John, WOW. What an excellent explanation. I havent looked you up in QRZ.com yet but I bet you have plenty of background to back up what you just said. When intelligent hams speak with such clarity as you just did , less smart hams (like myself) take notice. Stan K9IUQ
K9IUQ2007-02-26
Benchmarks
W4LGH doesnt give up and says: EVERY professional installation, the transmatch/tuner will be out at the antenna and NOT in the transmitter room, unless the antenna is being fed with open line.

..........................................

There is a very good reason for this. Professional Installations DONT change frequency. Most ham are frequency agile, that is they don't stay on one frequency like a Professional Installation Does.

When you change frequencys like most hams do, the situation changes, hence a tuner in the shack.

K9IUQ
W4LGH2007-02-26
RE: Benchmarks
KD2DB wrote~~~ If we were to take a half-wave dipole that has been properly cut for resonance at a particular operating frequency, we would expect to see a feed point impedance of about 60 ohms resistive.
============

Actually it is closer to 72ohms @ the feed point and not 60. The pi network on your tubes were designed to bring the 3000ohm output of the tube down to 50ohms to match the coax. Now if you have some weird impedance on your coax, you will not get it to tune. It is there to match the output to a known impedance of an antenna feed line. And you would be better off loss wise to feed the tube with a higher impedance open line, but the tradeoffs aren't worth it.

When you feed an antenna with an open line such as 300 or 450ohm line, you have effectively moved the antenna tuner out the the antenna. As you tune your tuner for the best possible match, you are tuning out all the reactance and impedance differences from the back of the tuner, so this includes the balanced feed line into the antenna. When you do this with coax, you are only tuning out the reactance at the END of the COAX, the mis-matches still apply along the coax and the antenna.

All of you do as you wish, and think as you wish, this is why on EVERY professional installation, the transmatch/tuner will be out at the antenna and NOT in the transmitter room, unless the antenna is being fed with open line.

Do whatever, I am tired of trying to explain this, as it is evident some of you just do get it. The loss may be low, or the loss may be HIGH, why have anymore loss than you should have. 1db can make a difference in being heard or not. Try the experiments I described earlier...you just see the light then. Especially the one where you completely disconnect your coax from your antenna, then tune your antenna tuner to a perfect match! See who you can talk to??
Also try this on your tube amp, remove the coax and see if you can load it up. Watch out for sparks!
Load up your coax with your tuner to you see 100watts, then go out to the antenna and insert the watt meter and see what you have. Very easy things to do, but do as you wish, as I am done trying to turn the lights on, as you can lead a horse to water, but you can't make him drink.

73 de W4LGH - ALan
http://www.w4lgh.com



Reply to a comment by : KD2BD on 2007-02-26

W4LGH wrote on February 26, 2007: > I have said all along that you can tune your antenna somewhat > using open feed line, as it becomes part of the antenna. It becomes "part of the antenna"? How so? What it is about coaxial line that keeps it "separate" from the antenna? If we were to take a half-wave dipole that has been properly cut for resonance at a particular operating frequency, we would expect to see a feed point impedance of about 60 ohms resistive. If we were to attach a length of 600 ohm balanced line to the antenna and bring it into the shack, the VSWR will be 10:1 throughout the entire length of the line. Unless the electrical length of the line just happens to be a multiple of a quarter wavelength at our operating frequency, the impedance we would see in the shack would be REACTIVE. In other words, it would be indicative of an antenna system that is NOT resonant at the design frequency, and would be no different in this regard than if we had cut the dipole too long or too short and fed it with coax. If we wish to properly terminate a 50 ohm transmitter into either one of these loads, we must "tune out" the reactance using an LC network (such as a tuner) TO ESTABLISH SYSTEM RESONANCE, and then transform the resistive component of the impedance to 50 ohms. And there's nothing wrong with that. > I still say that hooking un-balanced (coax) to your tuner is a JOKE. It is no more of a joke than using a Pi Network in a tube rig to match a 3000 ohm plate impedance to a 50 ohm unbalanced (coaxial) line. It is no more of a joke than using a broadband transformer in a solid state rig to match a 7 ohm collector impedance to a 50 ohm unbalanced (coaxial) line. Are we to believe these impedance matching networks, that are present in nearly EVERY transmitter, are FOOLING the tubes and/or transistors they contain because they transform impedances and terminate in an SO-239? Of course not. Should it make a difference whether the impedance matching network is contained inside or outside of the rig's cabinet? Of course not. 73, de John, KD2BD
Reply to a comment by : W4LGH on 2007-02-26

Stan K9IUQ wrote~~ And AL says "And to Stan, I appologize to you, for letting you push me to my limits." K9IUQ says there may be hope for you Al, the first step is admitting you can be wrong..... ================= Never said I was wrong, I said I apologize to you for letting you push me to far. I won't budge anymore. And M. Walter Maxwell did his studies back in the 1930's, he joined RCA in 1949, in 1958 he bcame a charter member of RCA's Astro-Electronics Center, and 1960 to his retirement, he was at the RCA Space Center in Princeton NJ. I know who he is, and what he said. And if you look at his current setup he uses an 80m dipole up at 65' fed with OPEN LINE (450ohm) hooked to a Balanced Trans-Match to tune it. He also has a 7 band folded unipole, again fed with OPEN LEAD (450ohm) to a 3KW BALANCED Trans-Match. Now I wonder why the "Expert" didn't bring in coax to his tuners/trans-match. He also states that he 80M dipole is RESONANT on 80M, and his Unipole is RESONANT on 160M. I have said all along that you can tune your antenna somewhat using open feed line, as it becomes part of the antenna. I still say that hooking un-balanced (coax) to your tuner is a JOKE...and it seems the expert does too as actions always speak louder than words. I said from the begining, and I still say, a RESONANT antenna will work better on the frequency it is resonant for than one that is non-resonant. The key words here are "BETTER" as I never said it wouldn't work, that RESONANT was better, and you CAN'T tune your antenna with a tuner in your shack hooked to COAX!. You can tune an Antenna, you can Tune a Guitar, BUT, you CAN NOT TUNAFISH! 73..Now go play radio! W4LGH - Alan http://www.w4lgh.com
Reply to a comment by : WB2WIK on 2007-02-26

>Benchmarks Reply by K9IUQ on February 26, 2007 Mail this to a friend! W4LGH Says "Also keep in mind that when all these experts like "Maxwell" was doing his thing, it was accepted that transmittions above 30 mhz were useless. And we all know how WRONG that was!" ..................................................... The Reflections book written by Maxwell was originally was written as articles in QST magazine during the 1970's. The original Reflections book which I own was published by the ARRL in 1991. It has been updated in Reflections II and III. Make no Mistake, Maxwell was and still is considered an expert.< ::Right you are. Walt Maxwell is still with us and his writings are recent and relevant. The *other* Maxwell, James Clerk Maxwell, whose work helped defined electromagnetic theory forever, died in 1879 before the first wireless radio contact had ever been made... WB2WIK/6
Reply to a comment by : K9IUQ on 2007-02-26

W4LGH Says "Also keep in mind that when all these experts like "Maxwell" was doing his thing, it was accepted that transmittions above 30 mhz were useless. And we all know how WRONG that was!" ..................................................... The Reflections book written by Maxwell was originally was written as articles in QST magazine during the 1970's. The original Reflections book which I own was published by the ARRL in 1991. It has been updated in Reflections II and III. Make no Mistake, Maxwell was and still is considered an expert. And AL says "And to Stan, I appologize to you, for letting you push me to my limits." K9IUQ says there may be hope for you Al, the first step is admitting you can be wrong..... Stan K9IUQ
N4SL2007-02-26
RE: Benchmarks
Please keep this thread alive, I laugh everytime I read it.
Reply to a comment by : K9IUQ on 2007-02-26

Kd2BD says Are we to believe these impedance matching networks, that are present in nearly EVERY transmitter, are FOOLING the tubes and/or transistors they contain because they transform impedances and terminate in an SO-239? Of course not. Should it make a difference whether the impedance matching network is contained inside or outside of the rig's cabinet? Of course not. 73, de John, KD2BD ....................................................... John, WOW. What an excellent explanation. I havent looked you up in QRZ.com yet but I bet you have plenty of background to back up what you just said. When intelligent hams speak with such clarity as you just did , less smart hams (like myself) take notice. Stan K9IUQ
K9IUQ2007-02-26
Benchmarks
Kd2BD says

Are we to believe these impedance matching networks, that are present in nearly EVERY transmitter, are FOOLING the tubes and/or transistors they contain because they transform impedances and terminate in an SO-239?

Of course not.

Should it make a difference whether the impedance matching network is contained inside or outside of the rig's cabinet?

Of course not.


73, de John, KD2BD

.......................................................

John, WOW. What an excellent explanation. I havent looked you up in QRZ.com yet but I bet you have plenty of background to back up what you just said. When intelligent hams speak with such clarity as you just did , less smart hams (like myself) take notice.

Stan K9IUQ



KD2BD2007-02-26
RE: Benchmarks
W4LGH wrote on February 26, 2007:

> I have said all along that you can tune your antenna somewhat
> using open feed line, as it becomes part of the antenna.

It becomes "part of the antenna"? How so? What it is about coaxial line that keeps it "separate" from the antenna?

If we were to take a half-wave dipole that has been properly cut for resonance at a particular operating frequency, we would expect to see a feed point impedance of about 60 ohms resistive.

If we were to attach a length of 600 ohm balanced line to the antenna and bring it into the shack, the VSWR will be 10:1 throughout the entire length of the line.

Unless the electrical length of the line just happens to be a multiple of a quarter wavelength at our operating frequency, the impedance we would see in the shack would be REACTIVE. In other words, it would be indicative of an antenna system that is NOT resonant at the design frequency, and would be no different in this regard than if we had cut the dipole too long or too short and fed it with coax.

If we wish to properly terminate a 50 ohm transmitter into either one of these loads, we must "tune out" the reactance using an LC network (such as a tuner) TO ESTABLISH SYSTEM RESONANCE, and then transform the resistive component of the impedance to 50 ohms.

And there's nothing wrong with that.

> I still say that hooking un-balanced (coax) to your tuner is a JOKE.

It is no more of a joke than using a Pi Network in a tube rig to match a 3000 ohm plate impedance to a 50 ohm unbalanced (coaxial) line.

It is no more of a joke than using a broadband transformer in a solid state rig to match a 7 ohm collector impedance to a 50 ohm unbalanced (coaxial) line.

Are we to believe these impedance matching networks, that are present in nearly EVERY transmitter, are FOOLING the tubes and/or transistors they contain because they transform impedances and terminate in an SO-239?

Of course not.

Should it make a difference whether the impedance matching network is contained inside or outside of the rig's cabinet?

Of course not.


73, de John, KD2BD
Reply to a comment by : W4LGH on 2007-02-26

Stan K9IUQ wrote~~ And AL says "And to Stan, I appologize to you, for letting you push me to my limits." K9IUQ says there may be hope for you Al, the first step is admitting you can be wrong..... ================= Never said I was wrong, I said I apologize to you for letting you push me to far. I won't budge anymore. And M. Walter Maxwell did his studies back in the 1930's, he joined RCA in 1949, in 1958 he bcame a charter member of RCA's Astro-Electronics Center, and 1960 to his retirement, he was at the RCA Space Center in Princeton NJ. I know who he is, and what he said. And if you look at his current setup he uses an 80m dipole up at 65' fed with OPEN LINE (450ohm) hooked to a Balanced Trans-Match to tune it. He also has a 7 band folded unipole, again fed with OPEN LEAD (450ohm) to a 3KW BALANCED Trans-Match. Now I wonder why the "Expert" didn't bring in coax to his tuners/trans-match. He also states that he 80M dipole is RESONANT on 80M, and his Unipole is RESONANT on 160M. I have said all along that you can tune your antenna somewhat using open feed line, as it becomes part of the antenna. I still say that hooking un-balanced (coax) to your tuner is a JOKE...and it seems the expert does too as actions always speak louder than words. I said from the begining, and I still say, a RESONANT antenna will work better on the frequency it is resonant for than one that is non-resonant. The key words here are "BETTER" as I never said it wouldn't work, that RESONANT was better, and you CAN'T tune your antenna with a tuner in your shack hooked to COAX!. You can tune an Antenna, you can Tune a Guitar, BUT, you CAN NOT TUNAFISH! 73..Now go play radio! W4LGH - Alan http://www.w4lgh.com
Reply to a comment by : WB2WIK on 2007-02-26

>Benchmarks Reply by K9IUQ on February 26, 2007 Mail this to a friend! W4LGH Says "Also keep in mind that when all these experts like "Maxwell" was doing his thing, it was accepted that transmittions above 30 mhz were useless. And we all know how WRONG that was!" ..................................................... The Reflections book written by Maxwell was originally was written as articles in QST magazine during the 1970's. The original Reflections book which I own was published by the ARRL in 1991. It has been updated in Reflections II and III. Make no Mistake, Maxwell was and still is considered an expert.< ::Right you are. Walt Maxwell is still with us and his writings are recent and relevant. The *other* Maxwell, James Clerk Maxwell, whose work helped defined electromagnetic theory forever, died in 1879 before the first wireless radio contact had ever been made... WB2WIK/6
Reply to a comment by : K9IUQ on 2007-02-26

W4LGH Says "Also keep in mind that when all these experts like "Maxwell" was doing his thing, it was accepted that transmittions above 30 mhz were useless. And we all know how WRONG that was!" ..................................................... The Reflections book written by Maxwell was originally was written as articles in QST magazine during the 1970's. The original Reflections book which I own was published by the ARRL in 1991. It has been updated in Reflections II and III. Make no Mistake, Maxwell was and still is considered an expert. And AL says "And to Stan, I appologize to you, for letting you push me to my limits." K9IUQ says there may be hope for you Al, the first step is admitting you can be wrong..... Stan K9IUQ
W4LGH2007-02-26
RE: Benchmarks
Stan K9IUQ wrote~~
And AL says "And to Stan, I appologize to you, for letting you push me to my limits."

K9IUQ says there may be hope for you Al, the first step is admitting you can be wrong.....
=================

Never said I was wrong, I said I apologize to you for letting you push me to far. I won't budge anymore. And M. Walter Maxwell did his studies back in the 1930's, he joined RCA in 1949, in 1958 he bcame a charter member of RCA's Astro-Electronics Center, and 1960 to his retirement, he was at the RCA Space Center in Princeton NJ. I know who he is, and what he said. And if you look at his current setup he uses an 80m dipole up at 65' fed with OPEN LINE (450ohm) hooked to a Balanced Trans-Match to tune it. He also has a 7 band folded unipole, again fed with OPEN LEAD (450ohm) to a 3KW BALANCED Trans-Match. Now I wonder why the "Expert" didn't bring in coax to his tuners/trans-match. He also states that he 80M dipole is RESONANT on 80M, and his Unipole is RESONANT on 160M.

I have said all along that you can tune your antenna somewhat using open feed line, as it becomes part of the antenna. I still say that hooking un-balanced (coax) to your tuner is a JOKE...and it seems the expert does too as actions always speak louder than words.

I said from the begining, and I still say, a RESONANT antenna will work better on the frequency it is resonant for than one that is non-resonant. The key words here are "BETTER" as I never said it wouldn't work, that RESONANT was better, and you CAN'T tune your antenna with a tuner in your shack hooked to COAX!.

You can tune an Antenna, you can Tune a Guitar, BUT, you CAN NOT TUNAFISH!

73..Now go play radio!
W4LGH - Alan
http://www.w4lgh.com


Reply to a comment by : WB2WIK on 2007-02-26

>Benchmarks Reply by K9IUQ on February 26, 2007 Mail this to a friend! W4LGH Says "Also keep in mind that when all these experts like "Maxwell" was doing his thing, it was accepted that transmittions above 30 mhz were useless. And we all know how WRONG that was!" ..................................................... The Reflections book written by Maxwell was originally was written as articles in QST magazine during the 1970's. The original Reflections book which I own was published by the ARRL in 1991. It has been updated in Reflections II and III. Make no Mistake, Maxwell was and still is considered an expert.< ::Right you are. Walt Maxwell is still with us and his writings are recent and relevant. The *other* Maxwell, James Clerk Maxwell, whose work helped defined electromagnetic theory forever, died in 1879 before the first wireless radio contact had ever been made... WB2WIK/6
Reply to a comment by : K9IUQ on 2007-02-26

W4LGH Says "Also keep in mind that when all these experts like "Maxwell" was doing his thing, it was accepted that transmittions above 30 mhz were useless. And we all know how WRONG that was!" ..................................................... The Reflections book written by Maxwell was originally was written as articles in QST magazine during the 1970's. The original Reflections book which I own was published by the ARRL in 1991. It has been updated in Reflections II and III. Make no Mistake, Maxwell was and still is considered an expert. And AL says "And to Stan, I appologize to you, for letting you push me to my limits." K9IUQ says there may be hope for you Al, the first step is admitting you can be wrong..... Stan K9IUQ
WB2WIK2007-02-26
RE: Benchmarks
>Benchmarks Reply
by K9IUQ on February 26, 2007 Mail this to a friend!
W4LGH Says "Also keep in mind that when all these experts like "Maxwell" was doing his thing, it was accepted that transmittions above 30 mhz were useless. And we all know how WRONG that was!"

.....................................................

The Reflections book written by Maxwell was originally was written as articles in QST magazine during the 1970's. The original Reflections book which I own was published by the ARRL in 1991. It has been updated in Reflections II and III. Make no Mistake, Maxwell was and still is considered an expert.<

::Right you are. Walt Maxwell is still with us and his writings are recent and relevant. The *other* Maxwell, James Clerk Maxwell, whose work helped defined electromagnetic theory forever, died in 1879 before the first wireless radio contact had ever been made...

WB2WIK/6
Reply to a comment by : K9IUQ on 2007-02-26

W4LGH Says "Also keep in mind that when all these experts like "Maxwell" was doing his thing, it was accepted that transmittions above 30 mhz were useless. And we all know how WRONG that was!" ..................................................... The Reflections book written by Maxwell was originally was written as articles in QST magazine during the 1970's. The original Reflections book which I own was published by the ARRL in 1991. It has been updated in Reflections II and III. Make no Mistake, Maxwell was and still is considered an expert. And AL says "And to Stan, I appologize to you, for letting you push me to my limits." K9IUQ says there may be hope for you Al, the first step is admitting you can be wrong..... Stan K9IUQ
K9IUQ2007-02-26
Benchmarks
W4LGH Says "Also keep in mind that when all these experts like "Maxwell" was doing his thing, it was accepted that transmittions above 30 mhz were useless. And we all know how WRONG that was!"

.....................................................

The Reflections book written by Maxwell was originally was written as articles in QST magazine during the 1970's. The original Reflections book which I own was published by the ARRL in 1991. It has been updated in Reflections II and III. Make no Mistake, Maxwell was and still is considered an expert.



And AL says "And to Stan, I appologize to you, for letting you push me to my limits."

K9IUQ says there may be hope for you Al, the first step is admitting you can be wrong.....


Stan K9IUQ



KC8QFP2007-02-26
RE: Benchmarks
Thanks for the input Al, very good! Saves me a lotta trouble. I'm gettin' older, and climbin' around on roofs doesn't thrill me much! This is a great example of how talkin' with other hams can really pay off.

And as for using a tuner, I use it because I prefer that the heat be there instead of in my transmitter. I prefer radiating RF more than heat, but at least the heat can go into the matchbox and not so much in my rig. If we were able to radiate most of the RF into the sky, that would be super. But there is gonna be some heat, nothing is 100% efficiant.

Don
Reply to a comment by : W4LGH on 2007-02-26

Just for the record, I installed a 4BTV on the roof of a poll barn. The roof is 25'x40' long and 100% metal. I use a 3' roof tripod to mount the antenna and bonded eveything to the roof. I thought this would make a super ground plane for the antenna, and it also put it about 30 feet in the air. I have NOT been able to get it to load up on all 4 bands. Can set any one of the bands and it works great then, however, the other 3 bands will not. The antenna worked fine sitting on a chainlinked fence. Just something to think about before you move yours. Its not my antenna, but at a friends house. We are gonna put it back on the fence and see if it is still working. 73 Alan
Reply to a comment by : KC8QFP on 2007-02-26

Mike, I feel that you are the exception rather than the common ham. I have to say that for some, traps and tuners are a necessary evil so to speak. We don't live in an ideal world, but we can dream. Like I said, for now, I have to use them too. I have to, but don't want to. Your whole situation is far different from mine, and I see your side and understand. But what I really appreciate about you on here, is that you demonstrate how this can be done properly and safely. Too many are careless and foolish with high power, and that can be DEADLY!!! In a way, it is a MUST to be fussy with tuners, traps, and high killerwatts. I will reitterate, since my $$ is tight, I'd prefer to invest in a really ""hot"" receiver in a rig. And I want an antenna that captures very well (I kinda like loops/quads). Maybe I am old fasioned, but for me, the more wire the better. At my old house (no alluminum siding there) I had a loop surrounding the roof of the house. And if a person has like a 50' deep backyard, that is pretty nice for many antennaes. I guess I dream of antenna farms amidst the trees. I am considering the alluminum siding as a ground plane, but it will not be ""matched"". I am debating taking the Hustler down and mounting it on the roof whereas all that siding, gutters, and chain-link fencing can be used as a ground plane, no wires underground! For now, all my 5BTV has is the fence. I have a ""benchmark"" dipole for 80m, and I want something better. All I am saying is that I am comofrtable with my barefoot rig, but need better antennaes. I feel no desire to blow a lot of cash on that other stuff. And I know traps are on the antenna, are they there to "trap birds"? I was referring to the linniker and tuner, aka "hot plate"! If your tuner is cool, that's kool! That shows that your antennaes are pretty close (not randumb wires). Your antennaes are probably mostly better than a XSWR of 3:1. Just keep in mind that many hams are clueless and think the tuner will solve everything and they can load up the ol' bedsprings! I bet you'll agree that tuners and traps are not for the ignorant, handle with care! 73, Don
Reply to a comment by : W4EF on 2007-02-25

KC8QFP wrote: >>My ears cannot tell the difference between a few db loss at the other end, that's my point. Some people feel they gotta spend a shitload of $$$ on tuners, feedline, traps, linears, and so on and it is not worth it, the guy at the other end will not be able to HEAR the difference between all that junk!<< Well, if you are rag chewing with a local on 75 meter SSB when band conditions are good, I would agree that a sh#%load of extra money spent on tuners, a "linniker", and the like doesn't buy you anything. In that case, 100 watts to a resonant dipole at 30 feet will usually do just fine. >>If you are using a 2KW linear, I would hope that you have the sense to have it connected to a very well matched antenna for goodnes sakes! Yes, there is a considerable db gain in such an amplifier. But I would think you had the sense to avoid a matchbox all the more with that kind of RF energy! Stray RF can be extreemly dangerous! Traps can explode, tuners arc, and shit gets mighty HOT with RF at even 1KW!<< Well if anything gets so hot that it explodes in my system, I take that as an indication that something is very wrong. The roller coil in my tuner gets a bit warm when I am running high power, but nothing dangerous. It's probably dissipating 0.3dB or something like that (60 watts out of 1000). With a carefully designed matching network at the feedpoint of the antenna, I could probably cut that in half. The mis-match at the antenna feedpoint after its transformed through the short coax is pretty modest, so I don't have any problems with the tuner arcing. I had an Alpha 91B in my shop recently and there were no problems running the tuner into the same mismatch at 1500 watts continuous. I don't have any problems with stray RF in the shack. That is mostly because I feed the vertical against a good counterpoise and I bring the coax feedline through a bulkhead which also connects to a good RF ground. Stray RF in the shack usually has more to do with common-mode current on feedlines than it does with where you do impedance matching. You can have a feedline with a very low SWR but lots of stray RF. And conversely, you can have a feedline with very high SWR, but no stray RF. >> But since you are a firm believer in traps and tuners, at least you won't need a microwave oven in your ham shack to keep your coffee and donuts warm.<< Traps are a bit of a compromise, but if properly designed they can work quite well. Personally I am not a "firm believer" in them pro or con. They are a tool which can be useful in certain instances. That's all. BTW, I am not sure how traps would keep my coffee and donuts warm. Perhaps that's why you have such a negative impression of them, Don. The really do work much better outdoors -:) >> I simply agree with Alan, you are better off without them (tuner/traps), even with a linear, better to a matched antenna!<< Well those things do cost money. So you shouldn't buy one if you don't need it. An antenna tuner is nothing more than a generalized matching network. You are more or less paying for the variable capacitors and variable inductor. In many cases, you can do a fixed matching network for less money (fixed inductors are cheap compared to roller inductors or even switched tapped inductors), but it won't have the flexibility of an antenna tuner. If you don't plan on changing anything and your cost conscious, I agree with you and Alan that a fixed network is the way to go. If on the other hand, you are changing things all the time, a tuner can be a convenient way to quickly realize an aribtrary matching network. I am always fiddling around with things, so for me, the tuner is a very useful tool. Manual antenna tuners are very cheap when you buy them used and they are simple, so usually there isn't anything wrong with them, and if there is, it's generally easy to fix. >>And even the 10db gain from your big linniker will not sound that dramatic to the other guy, he may not even notice much between you linear switched on or off, unless you tell him that is.<< That is certainly true when signal-to-noise ratios are high (again talking to your buddies on 75SSB). I don't use my amplifier when signals are strong for that very reason (in that case it's hard to argue that its anything but a waste of electricity). I use mine when the other guy can't hear me very well without it. In that case that extra 10dB of gain makes the difference between good copy and NO copy. I do a lot of CW DXing on 160 meters, so 9 times out of 10, I need the amplifier to make the contact (and many times I don't make the contact even with the linear). Thanks for your comments. 73, Mike W4EF......................
Reply to a comment by : N0EW on 2007-02-25

> And I still say using a tuner in your shack hooked to un-balanced line > (coax) is ABSURD! You are only fooling yourself and your radio. You are NOT > making your antenna work any better! This is one of my pet peeves, claiming that physics is some kind of underhanded trickery! Saying a "tuner" is able to "trick" another device -generally offered in terms of impedance matching- is like saying your power supply is "tricking" your transceiver into "thinking" it is getting something close to 12- or 13-volts dc, as opposed to the 120-volts ac that is coming out of the wall socket. It is madness! Now I'm all for trying to paint simple pictures to express basic ideas, I in fact do it quite often. However, at some point such short cuts actually create barriers to understanding. I feel this is one such example. Now, if we are all lucky, my computer will succeed in "tricking" the various other computers along the pathway between my home and the eHam server, and you will all get to read these words of wisdom, without which you would surely feel deprived (ya! right!) Heheh... Erik n0ew
Reply to a comment by : KD2BD on 2007-02-25

W4LGH wrote: > And I still say using a tuner in your shack hooked to un-balanced line > (coax) is ABSURD! You are only fooling yourself and your radio. You are NOT > making your antenna work any better! Not true. The tuner not only matching impedances, it also re-directs the reflected power in the transmission line back towards the antenna in the proper phase so it can be radiated along with the incident, forward power. The higher the SWR on the line, the more times the RF energy must bounce back and forth on the line before it is completely radiated by the antenna. Therefore, a low-loss line is very desirable under these circumstances. The tuner does not "fool" the transmitter or the operator. The voltage/current/power at the antenna terminals will, in fact, peak when the tuner is properly adjusted for the reasons stated above, and because the antenna SYSTEM has been brought into resonance, impedance matched to the transmitter, and tuned for maximum power transfer. Whether the tuner is located at the antenna, 5 feet down the line, 15 feet down the line, or 150 feet down the line doesn't matter (except for some additional feedline loss in the latter case because of the multiple bounces the RF must undergo on the line before every drop of RF is finally radiated by the antenna). While it may be difficult to remotely measure the voltage at the antenna terminals while you're adjusting the tuner, a simple relative field strength meter described in any edition of the ARRL Handbook would easily prove what I and others are saying is true. (And maximum radiated field strength is really what we're after, isn't it?) > Put the tuner/matching network @ the antenna, then you are doing something. This is a better approach, but it merely eliminates the additional loss incurred in the feedline due to the high VSWR. The Handbook illustrates how significant this additional loss is in the form of a series of curves. > Feed a dippole with open lead (balanced line) into your shack to a tuner, > then you are tuning the feed line into the antenna, and that works somewhat. "Tuning the feed line into the antenna"? What does THAT mean? :-) VSWR means the same thing and has the same effects whether the feedline is balanced or not. The only reason this approach works slightly better over RG/8 is because open wire line has very loss to begin with, and the additional transmission line loss produced by high VSWR is fairly insignificant to most HF operations. The wide spacing between the conductors yields a high breakdown voltage as well. > Install a resonant antenna system fed with low loss coax and now you > really have something nice, and its done the right way. Agreed. However, the approaches described earlier aren't nearly as bad as you're making them out to be. 73, de John, KD2BD
Reply to a comment by : N1EY on 2007-02-22

How is a vertical dipole more efficient? It would only depend on the ground system and the counterpoise. A regular vertical with a good ground and counterpoise is going to have positive dbI. A vertical dipole might not. N1EY
Reply to a comment by : ONAIR on 2007-02-22

Interesting point. So a resonant vertical dipole would then be a lot more efficient than a vertical that you would need to tune?
W4LGH2007-02-26
RE: Benchmarks
Just for the record, I installed a 4BTV on the roof of a poll barn. The roof is 25'x40' long and 100% metal. I use a 3' roof tripod to mount the antenna and bonded eveything to the roof. I thought this would make a super ground plane for the antenna, and it also put it about 30 feet in the air. I have NOT been able to get it to load up on all 4 bands. Can set any one of the bands and it works great then, however, the other 3 bands will not. The antenna worked fine sitting on a chainlinked fence. Just something to think about before you move yours. Its not my antenna, but at a friends house. We are gonna put it back on the fence and see if it is still working.

73 Alan
Reply to a comment by : KC8QFP on 2007-02-26

Mike, I feel that you are the exception rather than the common ham. I have to say that for some, traps and tuners are a necessary evil so to speak. We don't live in an ideal world, but we can dream. Like I said, for now, I have to use them too. I have to, but don't want to. Your whole situation is far different from mine, and I see your side and understand. But what I really appreciate about you on here, is that you demonstrate how this can be done properly and safely. Too many are careless and foolish with high power, and that can be DEADLY!!! In a way, it is a MUST to be fussy with tuners, traps, and high killerwatts. I will reitterate, since my $$ is tight, I'd prefer to invest in a really ""hot"" receiver in a rig. And I want an antenna that captures very well (I kinda like loops/quads). Maybe I am old fasioned, but for me, the more wire the better. At my old house (no alluminum siding there) I had a loop surrounding the roof of the house. And if a person has like a 50' deep backyard, that is pretty nice for many antennaes. I guess I dream of antenna farms amidst the trees. I am considering the alluminum siding as a ground plane, but it will not be ""matched"". I am debating taking the Hustler down and mounting it on the roof whereas all that siding, gutters, and chain-link fencing can be used as a ground plane, no wires underground! For now, all my 5BTV has is the fence. I have a ""benchmark"" dipole for 80m, and I want something better. All I am saying is that I am comofrtable with my barefoot rig, but need better antennaes. I feel no desire to blow a lot of cash on that other stuff. And I know traps are on the antenna, are they there to "trap birds"? I was referring to the linniker and tuner, aka "hot plate"! If your tuner is cool, that's kool! That shows that your antennaes are pretty close (not randumb wires). Your antennaes are probably mostly better than a XSWR of 3:1. Just keep in mind that many hams are clueless and think the tuner will solve everything and they can load up the ol' bedsprings! I bet you'll agree that tuners and traps are not for the ignorant, handle with care! 73, Don
Reply to a comment by : W4EF on 2007-02-25

KC8QFP wrote: >>My ears cannot tell the difference between a few db loss at the other end, that's my point. Some people feel they gotta spend a shitload of $$$ on tuners, feedline, traps, linears, and so on and it is not worth it, the guy at the other end will not be able to HEAR the difference between all that junk!<< Well, if you are rag chewing with a local on 75 meter SSB when band conditions are good, I would agree that a sh#%load of extra money spent on tuners, a "linniker", and the like doesn't buy you anything. In that case, 100 watts to a resonant dipole at 30 feet will usually do just fine. >>If you are using a 2KW linear, I would hope that you have the sense to have it connected to a very well matched antenna for goodnes sakes! Yes, there is a considerable db gain in such an amplifier. But I would think you had the sense to avoid a matchbox all the more with that kind of RF energy! Stray RF can be extreemly dangerous! Traps can explode, tuners arc, and shit gets mighty HOT with RF at even 1KW!<< Well if anything gets so hot that it explodes in my system, I take that as an indication that something is very wrong. The roller coil in my tuner gets a bit warm when I am running high power, but nothing dangerous. It's probably dissipating 0.3dB or something like that (60 watts out of 1000). With a carefully designed matching network at the feedpoint of the antenna, I could probably cut that in half. The mis-match at the antenna feedpoint after its transformed through the short coax is pretty modest, so I don't have any problems with the tuner arcing. I had an Alpha 91B in my shop recently and there were no problems running the tuner into the same mismatch at 1500 watts continuous. I don't have any problems with stray RF in the shack. That is mostly because I feed the vertical against a good counterpoise and I bring the coax feedline through a bulkhead which also connects to a good RF ground. Stray RF in the shack usually has more to do with common-mode current on feedlines than it does with where you do impedance matching. You can have a feedline with a very low SWR but lots of stray RF. And conversely, you can have a feedline with very high SWR, but no stray RF. >> But since you are a firm believer in traps and tuners, at least you won't need a microwave oven in your ham shack to keep your coffee and donuts warm.<< Traps are a bit of a compromise, but if properly designed they can work quite well. Personally I am not a "firm believer" in them pro or con. They are a tool which can be useful in certain instances. That's all. BTW, I am not sure how traps would keep my coffee and donuts warm. Perhaps that's why you have such a negative impression of them, Don. The really do work much better outdoors -:) >> I simply agree with Alan, you are better off without them (tuner/traps), even with a linear, better to a matched antenna!<< Well those things do cost money. So you shouldn't buy one if you don't need it. An antenna tuner is nothing more than a generalized matching network. You are more or less paying for the variable capacitors and variable inductor. In many cases, you can do a fixed matching network for less money (fixed inductors are cheap compared to roller inductors or even switched tapped inductors), but it won't have the flexibility of an antenna tuner. If you don't plan on changing anything and your cost conscious, I agree with you and Alan that a fixed network is the way to go. If on the other hand, you are changing things all the time, a tuner can be a convenient way to quickly realize an aribtrary matching network. I am always fiddling around with things, so for me, the tuner is a very useful tool. Manual antenna tuners are very cheap when you buy them used and they are simple, so usually there isn't anything wrong with them, and if there is, it's generally easy to fix. >>And even the 10db gain from your big linniker will not sound that dramatic to the other guy, he may not even notice much between you linear switched on or off, unless you tell him that is.<< That is certainly true when signal-to-noise ratios are high (again talking to your buddies on 75SSB). I don't use my amplifier when signals are strong for that very reason (in that case it's hard to argue that its anything but a waste of electricity). I use mine when the other guy can't hear me very well without it. In that case that extra 10dB of gain makes the difference between good copy and NO copy. I do a lot of CW DXing on 160 meters, so 9 times out of 10, I need the amplifier to make the contact (and many times I don't make the contact even with the linear). Thanks for your comments. 73, Mike W4EF......................
Reply to a comment by : N0EW on 2007-02-25

> And I still say using a tuner in your shack hooked to un-balanced line > (coax) is ABSURD! You are only fooling yourself and your radio. You are NOT > making your antenna work any better! This is one of my pet peeves, claiming that physics is some kind of underhanded trickery! Saying a "tuner" is able to "trick" another device -generally offered in terms of impedance matching- is like saying your power supply is "tricking" your transceiver into "thinking" it is getting something close to 12- or 13-volts dc, as opposed to the 120-volts ac that is coming out of the wall socket. It is madness! Now I'm all for trying to paint simple pictures to express basic ideas, I in fact do it quite often. However, at some point such short cuts actually create barriers to understanding. I feel this is one such example. Now, if we are all lucky, my computer will succeed in "tricking" the various other computers along the pathway between my home and the eHam server, and you will all get to read these words of wisdom, without which you would surely feel deprived (ya! right!) Heheh... Erik n0ew
Reply to a comment by : KD2BD on 2007-02-25

W4LGH wrote: > And I still say using a tuner in your shack hooked to un-balanced line > (coax) is ABSURD! You are only fooling yourself and your radio. You are NOT > making your antenna work any better! Not true. The tuner not only matching impedances, it also re-directs the reflected power in the transmission line back towards the antenna in the proper phase so it can be radiated along with the incident, forward power. The higher the SWR on the line, the more times the RF energy must bounce back and forth on the line before it is completely radiated by the antenna. Therefore, a low-loss line is very desirable under these circumstances. The tuner does not "fool" the transmitter or the operator. The voltage/current/power at the antenna terminals will, in fact, peak when the tuner is properly adjusted for the reasons stated above, and because the antenna SYSTEM has been brought into resonance, impedance matched to the transmitter, and tuned for maximum power transfer. Whether the tuner is located at the antenna, 5 feet down the line, 15 feet down the line, or 150 feet down the line doesn't matter (except for some additional feedline loss in the latter case because of the multiple bounces the RF must undergo on the line before every drop of RF is finally radiated by the antenna). While it may be difficult to remotely measure the voltage at the antenna terminals while you're adjusting the tuner, a simple relative field strength meter described in any edition of the ARRL Handbook would easily prove what I and others are saying is true. (And maximum radiated field strength is really what we're after, isn't it?) > Put the tuner/matching network @ the antenna, then you are doing something. This is a better approach, but it merely eliminates the additional loss incurred in the feedline due to the high VSWR. The Handbook illustrates how significant this additional loss is in the form of a series of curves. > Feed a dippole with open lead (balanced line) into your shack to a tuner, > then you are tuning the feed line into the antenna, and that works somewhat. "Tuning the feed line into the antenna"? What does THAT mean? :-) VSWR means the same thing and has the same effects whether the feedline is balanced or not. The only reason this approach works slightly better over RG/8 is because open wire line has very loss to begin with, and the additional transmission line loss produced by high VSWR is fairly insignificant to most HF operations. The wide spacing between the conductors yields a high breakdown voltage as well. > Install a resonant antenna system fed with low loss coax and now you > really have something nice, and its done the right way. Agreed. However, the approaches described earlier aren't nearly as bad as you're making them out to be. 73, de John, KD2BD
Reply to a comment by : N1EY on 2007-02-22

How is a vertical dipole more efficient? It would only depend on the ground system and the counterpoise. A regular vertical with a good ground and counterpoise is going to have positive dbI. A vertical dipole might not. N1EY
Reply to a comment by : ONAIR on 2007-02-22

Interesting point. So a resonant vertical dipole would then be a lot more efficient than a vertical that you would need to tune?
KC8QFP2007-02-26
RE: Benchmarks
I was pondering making a "variable antenna". I have an old Skil electric screwdriver that turns a nice slow RPM with lots of torque. If I were to mount a metal spool on the middle of a loop, the bare wire antenna could be lengthened or shortened by forward or reversing the screwdriver. It only takes a few VDC for it oo. The darn thing has been sittin' on my bench for years collecting dust (I'm a packrat and it is just another junkbox item). The slack or tension of the variable antenna can be taken up by using bungiee cords. At first I was thinking about mounting the screwdriver to a variable cap at the feedpoint. This has been done in magazine articals I've seen, and all I'd need is the cap. But I like the idea of using it like a fishing reel so to speak. Comments welcome!

Don
Reply to a comment by : KC8QFP on 2007-02-26

Mike, I feel that you are the exception rather than the common ham. I have to say that for some, traps and tuners are a necessary evil so to speak. We don't live in an ideal world, but we can dream. Like I said, for now, I have to use them too. I have to, but don't want to. Your whole situation is far different from mine, and I see your side and understand. But what I really appreciate about you on here, is that you demonstrate how this can be done properly and safely. Too many are careless and foolish with high power, and that can be DEADLY!!! In a way, it is a MUST to be fussy with tuners, traps, and high killerwatts. I will reitterate, since my $$ is tight, I'd prefer to invest in a really ""hot"" receiver in a rig. And I want an antenna that captures very well (I kinda like loops/quads). Maybe I am old fasioned, but for me, the more wire the better. At my old house (no alluminum siding there) I had a loop surrounding the roof of the house. And if a person has like a 50' deep backyard, that is pretty nice for many antennaes. I guess I dream of antenna farms amidst the trees. I am considering the alluminum siding as a ground plane, but it will not be ""matched"". I am debating taking the Hustler down and mounting it on the roof whereas all that siding, gutters, and chain-link fencing can be used as a ground plane, no wires underground! For now, all my 5BTV has is the fence. I have a ""benchmark"" dipole for 80m, and I want something better. All I am saying is that I am comofrtable with my barefoot rig, but need better antennaes. I feel no desire to blow a lot of cash on that other stuff. And I know traps are on the antenna, are they there to "trap birds"? I was referring to the linniker and tuner, aka "hot plate"! If your tuner is cool, that's kool! That shows that your antennaes are pretty close (not randumb wires). Your antennaes are probably mostly better than a XSWR of 3:1. Just keep in mind that many hams are clueless and think the tuner will solve everything and they can load up the ol' bedsprings! I bet you'll agree that tuners and traps are not for the ignorant, handle with care! 73, Don
Reply to a comment by : W4EF on 2007-02-25

KC8QFP wrote: >>My ears cannot tell the difference between a few db loss at the other end, that's my point. Some people feel they gotta spend a shitload of $$$ on tuners, feedline, traps, linears, and so on and it is not worth it, the guy at the other end will not be able to HEAR the difference between all that junk!<< Well, if you are rag chewing with a local on 75 meter SSB when band conditions are good, I would agree that a sh#%load of extra money spent on tuners, a "linniker", and the like doesn't buy you anything. In that case, 100 watts to a resonant dipole at 30 feet will usually do just fine. >>If you are using a 2KW linear, I would hope that you have the sense to have it connected to a very well matched antenna for goodnes sakes! Yes, there is a considerable db gain in such an amplifier. But I would think you had the sense to avoid a matchbox all the more with that kind of RF energy! Stray RF can be extreemly dangerous! Traps can explode, tuners arc, and shit gets mighty HOT with RF at even 1KW!<< Well if anything gets so hot that it explodes in my system, I take that as an indication that something is very wrong. The roller coil in my tuner gets a bit warm when I am running high power, but nothing dangerous. It's probably dissipating 0.3dB or something like that (60 watts out of 1000). With a carefully designed matching network at the feedpoint of the antenna, I could probably cut that in half. The mis-match at the antenna feedpoint after its transformed through the short coax is pretty modest, so I don't have any problems with the tuner arcing. I had an Alpha 91B in my shop recently and there were no problems running the tuner into the same mismatch at 1500 watts continuous. I don't have any problems with stray RF in the shack. That is mostly because I feed the vertical against a good counterpoise and I bring the coax feedline through a bulkhead which also connects to a good RF ground. Stray RF in the shack usually has more to do with common-mode current on feedlines than it does with where you do impedance matching. You can have a feedline with a very low SWR but lots of stray RF. And conversely, you can have a feedline with very high SWR, but no stray RF. >> But since you are a firm believer in traps and tuners, at least you won't need a microwave oven in your ham shack to keep your coffee and donuts warm.<< Traps are a bit of a compromise, but if properly designed they can work quite well. Personally I am not a "firm believer" in them pro or con. They are a tool which can be useful in certain instances. That's all. BTW, I am not sure how traps would keep my coffee and donuts warm. Perhaps that's why you have such a negative impression of them, Don. The really do work much better outdoors -:) >> I simply agree with Alan, you are better off without them (tuner/traps), even with a linear, better to a matched antenna!<< Well those things do cost money. So you shouldn't buy one if you don't need it. An antenna tuner is nothing more than a generalized matching network. You are more or less paying for the variable capacitors and variable inductor. In many cases, you can do a fixed matching network for less money (fixed inductors are cheap compared to roller inductors or even switched tapped inductors), but it won't have the flexibility of an antenna tuner. If you don't plan on changing anything and your cost conscious, I agree with you and Alan that a fixed network is the way to go. If on the other hand, you are changing things all the time, a tuner can be a convenient way to quickly realize an aribtrary matching network. I am always fiddling around with things, so for me, the tuner is a very useful tool. Manual antenna tuners are very cheap when you buy them used and they are simple, so usually there isn't anything wrong with them, and if there is, it's generally easy to fix. >>And even the 10db gain from your big linniker will not sound that dramatic to the other guy, he may not even notice much between you linear switched on or off, unless you tell him that is.<< That is certainly true when signal-to-noise ratios are high (again talking to your buddies on 75SSB). I don't use my amplifier when signals are strong for that very reason (in that case it's hard to argue that its anything but a waste of electricity). I use mine when the other guy can't hear me very well without it. In that case that extra 10dB of gain makes the difference between good copy and NO copy. I do a lot of CW DXing on 160 meters, so 9 times out of 10, I need the amplifier to make the contact (and many times I don't make the contact even with the linear). Thanks for your comments. 73, Mike W4EF......................
Reply to a comment by : N0EW on 2007-02-25

> And I still say using a tuner in your shack hooked to un-balanced line > (coax) is ABSURD! You are only fooling yourself and your radio. You are NOT > making your antenna work any better! This is one of my pet peeves, claiming that physics is some kind of underhanded trickery! Saying a "tuner" is able to "trick" another device -generally offered in terms of impedance matching- is like saying your power supply is "tricking" your transceiver into "thinking" it is getting something close to 12- or 13-volts dc, as opposed to the 120-volts ac that is coming out of the wall socket. It is madness! Now I'm all for trying to paint simple pictures to express basic ideas, I in fact do it quite often. However, at some point such short cuts actually create barriers to understanding. I feel this is one such example. Now, if we are all lucky, my computer will succeed in "tricking" the various other computers along the pathway between my home and the eHam server, and you will all get to read these words of wisdom, without which you would surely feel deprived (ya! right!) Heheh... Erik n0ew
Reply to a comment by : KD2BD on 2007-02-25

W4LGH wrote: > And I still say using a tuner in your shack hooked to un-balanced line > (coax) is ABSURD! You are only fooling yourself and your radio. You are NOT > making your antenna work any better! Not true. The tuner not only matching impedances, it also re-directs the reflected power in the transmission line back towards the antenna in the proper phase so it can be radiated along with the incident, forward power. The higher the SWR on the line, the more times the RF energy must bounce back and forth on the line before it is completely radiated by the antenna. Therefore, a low-loss line is very desirable under these circumstances. The tuner does not "fool" the transmitter or the operator. The voltage/current/power at the antenna terminals will, in fact, peak when the tuner is properly adjusted for the reasons stated above, and because the antenna SYSTEM has been brought into resonance, impedance matched to the transmitter, and tuned for maximum power transfer. Whether the tuner is located at the antenna, 5 feet down the line, 15 feet down the line, or 150 feet down the line doesn't matter (except for some additional feedline loss in the latter case because of the multiple bounces the RF must undergo on the line before every drop of RF is finally radiated by the antenna). While it may be difficult to remotely measure the voltage at the antenna terminals while you're adjusting the tuner, a simple relative field strength meter described in any edition of the ARRL Handbook would easily prove what I and others are saying is true. (And maximum radiated field strength is really what we're after, isn't it?) > Put the tuner/matching network @ the antenna, then you are doing something. This is a better approach, but it merely eliminates the additional loss incurred in the feedline due to the high VSWR. The Handbook illustrates how significant this additional loss is in the form of a series of curves. > Feed a dippole with open lead (balanced line) into your shack to a tuner, > then you are tuning the feed line into the antenna, and that works somewhat. "Tuning the feed line into the antenna"? What does THAT mean? :-) VSWR means the same thing and has the same effects whether the feedline is balanced or not. The only reason this approach works slightly better over RG/8 is because open wire line has very loss to begin with, and the additional transmission line loss produced by high VSWR is fairly insignificant to most HF operations. The wide spacing between the conductors yields a high breakdown voltage as well. > Install a resonant antenna system fed with low loss coax and now you > really have something nice, and its done the right way. Agreed. However, the approaches described earlier aren't nearly as bad as you're making them out to be. 73, de John, KD2BD
Reply to a comment by : N1EY on 2007-02-22

How is a vertical dipole more efficient? It would only depend on the ground system and the counterpoise. A regular vertical with a good ground and counterpoise is going to have positive dbI. A vertical dipole might not. N1EY
Reply to a comment by : ONAIR on 2007-02-22

Interesting point. So a resonant vertical dipole would then be a lot more efficient than a vertical that you would need to tune?
KC8QFP2007-02-26
RE: Benchmarks
Mike, I feel that you are the exception rather than the common ham. I have to say that for some, traps and tuners are a necessary evil so to speak. We don't live in an ideal world, but we can dream. Like I said, for now, I have to use them too. I have to, but don't want to. Your whole situation is far different from mine, and I see your side and understand. But what I really appreciate about you on here, is that you demonstrate how this can be done properly and safely. Too many are careless and foolish with high power, and that can be DEADLY!!! In a way, it is a MUST to be fussy with tuners, traps, and high killerwatts. I will reitterate, since my $$ is tight, I'd prefer to invest in a really ""hot"" receiver in a rig. And I want an antenna that captures very well (I kinda like loops/quads). Maybe I am old fasioned, but for me, the more wire the better. At my old house (no alluminum siding there) I had a loop surrounding the roof of the house. And if a person has like a 50' deep backyard, that is pretty nice for many antennaes. I guess I dream of antenna farms amidst the trees. I am considering the alluminum siding as a ground plane, but it will not be ""matched"". I am debating taking the Hustler down and mounting it on the roof whereas all that siding, gutters, and chain-link fencing can be used as a ground plane, no wires underground! For now, all my 5BTV has is the fence. I have a ""benchmark"" dipole for 80m, and I want something better. All I am saying is that I am comofrtable with my barefoot rig, but need better antennaes. I feel no desire to blow a lot of cash on that other stuff. And I know traps are on the antenna, are they there to "trap birds"? I was referring to the linniker and tuner, aka "hot plate"! If your tuner is cool, that's kool! That shows that your antennaes are pretty close (not randumb wires). Your antennaes are probably mostly better than a XSWR of 3:1. Just keep in mind that many hams are clueless and think the tuner will solve everything and they can load up the ol' bedsprings! I bet you'll agree that tuners and traps are not for the ignorant, handle with care!

73, Don
Reply to a comment by : W4EF on 2007-02-25

KC8QFP wrote: >>My ears cannot tell the difference between a few db loss at the other end, that's my point. Some people feel they gotta spend a shitload of $$$ on tuners, feedline, traps, linears, and so on and it is not worth it, the guy at the other end will not be able to HEAR the difference between all that junk!<< Well, if you are rag chewing with a local on 75 meter SSB when band conditions are good, I would agree that a sh#%load of extra money spent on tuners, a "linniker", and the like doesn't buy you anything. In that case, 100 watts to a resonant dipole at 30 feet will usually do just fine. >>If you are using a 2KW linear, I would hope that you have the sense to have it connected to a very well matched antenna for goodnes sakes! Yes, there is a considerable db gain in such an amplifier. But I would think you had the sense to avoid a matchbox all the more with that kind of RF energy! Stray RF can be extreemly dangerous! Traps can explode, tuners arc, and shit gets mighty HOT with RF at even 1KW!<< Well if anything gets so hot that it explodes in my system, I take that as an indication that something is very wrong. The roller coil in my tuner gets a bit warm when I am running high power, but nothing dangerous. It's probably dissipating 0.3dB or something like that (60 watts out of 1000). With a carefully designed matching network at the feedpoint of the antenna, I could probably cut that in half. The mis-match at the antenna feedpoint after its transformed through the short coax is pretty modest, so I don't have any problems with the tuner arcing. I had an Alpha 91B in my shop recently and there were no problems running the tuner into the same mismatch at 1500 watts continuous. I don't have any problems with stray RF in the shack. That is mostly because I feed the vertical against a good counterpoise and I bring the coax feedline through a bulkhead which also connects to a good RF ground. Stray RF in the shack usually has more to do with common-mode current on feedlines than it does with where you do impedance matching. You can have a feedline with a very low SWR but lots of stray RF. And conversely, you can have a feedline with very high SWR, but no stray RF. >> But since you are a firm believer in traps and tuners, at least you won't need a microwave oven in your ham shack to keep your coffee and donuts warm.<< Traps are a bit of a compromise, but if properly designed they can work quite well. Personally I am not a "firm believer" in them pro or con. They are a tool which can be useful in certain instances. That's all. BTW, I am not sure how traps would keep my coffee and donuts warm. Perhaps that's why you have such a negative impression of them, Don. The really do work much better outdoors -:) >> I simply agree with Alan, you are better off without them (tuner/traps), even with a linear, better to a matched antenna!<< Well those things do cost money. So you shouldn't buy one if you don't need it. An antenna tuner is nothing more than a generalized matching network. You are more or less paying for the variable capacitors and variable inductor. In many cases, you can do a fixed matching network for less money (fixed inductors are cheap compared to roller inductors or even switched tapped inductors), but it won't have the flexibility of an antenna tuner. If you don't plan on changing anything and your cost conscious, I agree with you and Alan that a fixed network is the way to go. If on the other hand, you are changing things all the time, a tuner can be a convenient way to quickly realize an aribtrary matching network. I am always fiddling around with things, so for me, the tuner is a very useful tool. Manual antenna tuners are very cheap when you buy them used and they are simple, so usually there isn't anything wrong with them, and if there is, it's generally easy to fix. >>And even the 10db gain from your big linniker will not sound that dramatic to the other guy, he may not even notice much between you linear switched on or off, unless you tell him that is.<< That is certainly true when signal-to-noise ratios are high (again talking to your buddies on 75SSB). I don't use my amplifier when signals are strong for that very reason (in that case it's hard to argue that its anything but a waste of electricity). I use mine when the other guy can't hear me very well without it. In that case that extra 10dB of gain makes the difference between good copy and NO copy. I do a lot of CW DXing on 160 meters, so 9 times out of 10, I need the amplifier to make the contact (and many times I don't make the contact even with the linear). Thanks for your comments. 73, Mike W4EF......................
Reply to a comment by : N0EW on 2007-02-25

> And I still say using a tuner in your shack hooked to un-balanced line > (coax) is ABSURD! You are only fooling yourself and your radio. You are NOT > making your antenna work any better! This is one of my pet peeves, claiming that physics is some kind of underhanded trickery! Saying a "tuner" is able to "trick" another device -generally offered in terms of impedance matching- is like saying your power supply is "tricking" your transceiver into "thinking" it is getting something close to 12- or 13-volts dc, as opposed to the 120-volts ac that is coming out of the wall socket. It is madness! Now I'm all for trying to paint simple pictures to express basic ideas, I in fact do it quite often. However, at some point such short cuts actually create barriers to understanding. I feel this is one such example. Now, if we are all lucky, my computer will succeed in "tricking" the various other computers along the pathway between my home and the eHam server, and you will all get to read these words of wisdom, without which you would surely feel deprived (ya! right!) Heheh... Erik n0ew
Reply to a comment by : KD2BD on 2007-02-25

W4LGH wrote: > And I still say using a tuner in your shack hooked to un-balanced line > (coax) is ABSURD! You are only fooling yourself and your radio. You are NOT > making your antenna work any better! Not true. The tuner not only matching impedances, it also re-directs the reflected power in the transmission line back towards the antenna in the proper phase so it can be radiated along with the incident, forward power. The higher the SWR on the line, the more times the RF energy must bounce back and forth on the line before it is completely radiated by the antenna. Therefore, a low-loss line is very desirable under these circumstances. The tuner does not "fool" the transmitter or the operator. The voltage/current/power at the antenna terminals will, in fact, peak when the tuner is properly adjusted for the reasons stated above, and because the antenna SYSTEM has been brought into resonance, impedance matched to the transmitter, and tuned for maximum power transfer. Whether the tuner is located at the antenna, 5 feet down the line, 15 feet down the line, or 150 feet down the line doesn't matter (except for some additional feedline loss in the latter case because of the multiple bounces the RF must undergo on the line before every drop of RF is finally radiated by the antenna). While it may be difficult to remotely measure the voltage at the antenna terminals while you're adjusting the tuner, a simple relative field strength meter described in any edition of the ARRL Handbook would easily prove what I and others are saying is true. (And maximum radiated field strength is really what we're after, isn't it?) > Put the tuner/matching network @ the antenna, then you are doing something. This is a better approach, but it merely eliminates the additional loss incurred in the feedline due to the high VSWR. The Handbook illustrates how significant this additional loss is in the form of a series of curves. > Feed a dippole with open lead (balanced line) into your shack to a tuner, > then you are tuning the feed line into the antenna, and that works somewhat. "Tuning the feed line into the antenna"? What does THAT mean? :-) VSWR means the same thing and has the same effects whether the feedline is balanced or not. The only reason this approach works slightly better over RG/8 is because open wire line has very loss to begin with, and the additional transmission line loss produced by high VSWR is fairly insignificant to most HF operations. The wide spacing between the conductors yields a high breakdown voltage as well. > Install a resonant antenna system fed with low loss coax and now you > really have something nice, and its done the right way. Agreed. However, the approaches described earlier aren't nearly as bad as you're making them out to be. 73, de John, KD2BD
Reply to a comment by : N1EY on 2007-02-22

How is a vertical dipole more efficient? It would only depend on the ground system and the counterpoise. A regular vertical with a good ground and counterpoise is going to have positive dbI. A vertical dipole might not. N1EY
Reply to a comment by : ONAIR on 2007-02-22

Interesting point. So a resonant vertical dipole would then be a lot more efficient than a vertical that you would need to tune?
W4LGH2007-02-26
RE: Benchmarks
Absoultly you can Stan, but you keep at it over and over and over, with your consistant winning, he said ,they said, you said, and everyone has their limits. You can keep on quoting whoever you want, I will not let you push anymore...so go suck an egg!!

Here are some interesting quotes that I found this weekend about antenna tuners in the shack on un-balanced lines. Found these quiet interestings. I also read "The Easy Way" with much info from Walter Maxwell....

From ARRL Website:

Yes, it's true-an antenna tuner doesn't really tune your antenna in the strict sense of the word. It does not, for example, adjust the lengths of your antenna elements, their heights above ground and so on. What an antenna tuner or transmatch does do, however, is transform the impedance at the feed line input to a value that your transceiver can handle (typically 50 Ohm-see Figure 1). When thinking about antenna tuners and SWR, it's important to remember that the tuner has no effect whatsoever on the SWR between itself and the antenna. It's the SWR between the tuner and the transceiver that changes.

In practical terms, all a tuner does is act as a kind of adjustable impedance transformer between the antenna system and the radio. It takes whatever impedance the antenna system presents and attempts to convert it to 50 Ohm--or something reasonably close to that value--for the transceiver. When the transceiver "sees" a 50 Ohm impedance, it is able to load its maximum RF output into the system. That power is transferred through the antenna tuner, to the feed line and, ultimately, to the antenna--minus any losses incurred along the way.

These losses are the reason that the highest efficiency feed-line for each individual case is desirable and why some amateurs use ladder line.
=======

No Tuner Antenna System
By Howard E. Cann, Jr., KA3MRX

Tuners are a compromise to fool your radio into thinking it is seeing a resonant antenna. It can be an inefficient way of working radio, since some of your precious power is being wasted in the tuner as heat. The amount varies, depending on the antenna and the frequency. Although there may not be a great amount wasted, you will want all the power to get to the antenna and out into the airwaves as you intend
========
From Hamuniverse.com
Yes, "TRICK" YOUR RIG!
WHAT IS AN ANTENNA TUNNER?

You have to learn how to hook them up to your tranceiver properly and tune them correctly to make your radio THINK that it is feeding it's signal into a "perfect or near perfect 50 ohm load called your antenna. An antenna tuner, (transmatch), doesn't really TUNE your antenna OR ANY PART OF IT!
=========

From Answers.com

Antenna Tuner
An antenna tuner, transmatch, antenna tuning unit, or ATU matches a transceiver with a fixed impedance (typically 50 ohms for modern transceivers) to a load (feed line and antenna) impedance which is unknown, complex or otherwise does not match. This mismatch is usually caused when using a non-resonant antenna, one that is not the correct electrical length as compared to the wavelength of the signal. An ATU allows the use of one antenna for a broad range of frequencies. A tuned antenna is never as good as a naturally resonant antenna due to additional induced losses on the feed line due to the SWR (multiple reflections), and losses in the ATU itself.

Strictly speaking the 'ATU' is only an antenna matching unit, as it is unable to change the RESONANT frequency of the aerial.

========

Some interesting points are made, but I still say you are only fooling yourself and radio. That the only way to go is a RESONANT antenna, antenna system for the frequency desired. I said it from the begining, and I have not changed my opinion.

A famous man once said "even a little rf radiated, is rf radiated, and someone will probably hear you!" I just like to get as much of my original rf produced radiated so others will hear me as well.

Next time you are playing with your antenna tuner in your shack try this simple experiment for yourself. Hook an SWR/POWER meter AFTER your tuner, switch your tuner in and adjust to your satisfaction, now look at the power meter after the tuner. Now switch the tuner in/out, watching the external meter, and note the difference, I think you will be shocked. Now if you have a remote meter that you can put at the far end of your coax, do the same thing, and note the difference. This will truely amaze you. Instead of taking the word of others, try some experimenting yourself, document the results and form your own conclusions. Another interesting experiment, disconnect your antenna completely, tune your tuner for a perfect match! You'll need a couple of watt meters, and a field strength meter.

Also keep in mind that when all these experts like "Maxwell" was doing his thing, it was accepted that transmittions above 30 mhz were useless. And we all know how WRONG that was! Math is math, but maybe some of the known varibles were incorrect?

Have fun and play radio!
73 de W4LGH - Alan
http://www.w4lgh.com

And to Stan, I appologize to you, for letting you push me to my limits.
Reply to a comment by : K9IUQ on 2007-02-26

W4LGH continues ranting : I still say you sir are an IDIOT, and I still think you should buy the ocean front properity in Azronia, while its still a bargin! Stan you can spin it anyway you want, say whatever you want, its a free country. I know what I have said, and I know what everyone else on here has said, including you sir. I am done with this silly ass you said, he said, they said, BS. I will send you some cheese to go with your wine, but you can have it all to yourself. Say you won if you want, call it whatever, but I am not longer going to play your silly game. ........................................................ Al, here are some words you wrote in your article on Eham titled Fraternal Brotherhood of Hams.Direct quote no spin. From friendly debater W4LGH: "I have always been told it is OK to disagree with a theory/idea, but on here it becomes a MAJOR event with slanderous comments and name-calling. I fail to see or understand why someone would get so upset about a comment and resort to these immature ways. If you don't like something, its OK to say, I don't like it and move on." ................. Al my friend YOU wrote the above. Can we BELIEVE anything you write????? K9IUQ
K9IUQ2007-02-26
Benchmarks
W4LGH continues ranting : I still
say you sir are an IDIOT, and I still think you should buy the ocean front properity in Azronia, while its still a bargin! Stan you can spin it anyway you want, say whatever you want, its a free country. I know what I have said, and I know what everyone else on here has said, including you sir. I am done with this silly ass you said, he said, they said, BS.
I will send you some cheese to go with your wine, but you can have it all to yourself. Say you won if you want, call it whatever, but I am not longer going to play your silly game.


........................................................

Al, here are some words you wrote in your article on Eham titled Fraternal Brotherhood of Hams.Direct quote no spin. From friendly debater W4LGH:

"I have always been told it is OK to disagree with a theory/idea, but on here it becomes a MAJOR event with slanderous comments and name-calling. I fail to see or understand why someone would get so upset about a comment and resort to these immature ways. If you don't like something, its OK to say, I don't like it and move on."

.................
Al my friend YOU wrote the above. Can we BELIEVE anything you write?????

K9IUQ


K9IUQ2007-02-26
Benchmarks
Lets put this "antenna tuner's on coax is bad" CRAP to bed. It has all been researched in the antenna literature many times.

Go to this link and read Matching at the Line input by Walter Maxwell.Its on page 7-5. It dispels much of what has been said here.This paragraph is in the chapter "My Antenna Tuner really Does Tune My Antenna. The chapter is interesting but much of it is directed at people smarter than I. But read "Matching at the Line input", it will be perfectly clear to most hams why tuners are not always bad boys.

http://www.w2du.com/Chapter07.pdf

If you REALLY want to learn the TRUTH about antennas, transmissions lines and Myths, read some of the other chapters on this website. www.w2du.com
Stan K9IUQ
W4EF2007-02-25
RE: Benchmarks
KC8QFP wrote:

>>My ears cannot tell the difference between a few db loss at the other end, that's my point. Some people feel they gotta spend a shitload of $$$ on tuners, feedline, traps, linears, and so on and it is not worth it, the guy at the other end will not be able to HEAR the difference between all that junk!<<

Well, if you are rag chewing with a local on 75 meter SSB when band conditions are good, I would agree that a sh#%load of extra money spent on tuners, a "linniker", and the like doesn't buy you anything. In that case, 100 watts to a resonant dipole at 30 feet will usually do just fine.

>>If you are using a 2KW linear, I would hope that you have the sense to have it connected to a very well matched antenna for goodnes sakes! Yes, there is a considerable db gain in such an amplifier. But I would think you had the sense to avoid a matchbox all the more with that kind of RF energy! Stray RF can be extreemly dangerous! Traps can explode, tuners arc, and shit gets mighty HOT with RF at even 1KW!<<

Well if anything gets so hot that it explodes in my system, I take that as an indication that something is very wrong. The roller coil in my tuner gets a bit warm when I am running high power, but nothing dangerous. It's probably dissipating 0.3dB or something like that (60 watts out of 1000). With a carefully designed matching network at the feedpoint of the antenna, I could probably cut that in half.

The mis-match at the antenna feedpoint after its transformed through the short coax is pretty modest, so I don't have any problems with the tuner arcing. I had an Alpha 91B in my shop recently and there were no problems running the tuner into the same mismatch at 1500 watts continuous.

I don't have any problems with stray RF in the shack.
That is mostly because I feed the vertical against a good counterpoise and I bring the coax feedline through a bulkhead which also connects to a good RF ground. Stray RF in the shack usually has more to do with common-mode current on feedlines than it does with where you do impedance matching. You can have a feedline with a very low SWR but lots of stray RF. And conversely, you can have a feedline with very high SWR, but no stray RF.

>> But since you are a firm believer in traps and tuners, at least you won't need a microwave oven in your ham shack to keep your coffee and donuts warm.<<

Traps are a bit of a compromise, but if properly designed they can work quite well. Personally I am not a "firm believer" in them pro or con. They are a tool which can be useful in certain instances. That's all.
BTW, I am not sure how traps would keep my coffee and donuts warm. Perhaps that's why you have such a negative impression of them, Don. The really do work much better outdoors -:)

>> I simply agree with Alan, you are better off without them (tuner/traps), even with a linear, better to a matched antenna!<<

Well those things do cost money. So you shouldn't buy one if you don't need it. An antenna tuner is nothing more than a generalized matching network. You are more or less paying for the variable capacitors and variable inductor. In many cases, you can do a fixed matching network for less money (fixed inductors are cheap compared to roller inductors or even switched tapped inductors), but it won't have the flexibility of an antenna tuner. If you don't plan on changing anything and your cost conscious, I agree with you and Alan that a fixed network is the way to go. If on the other hand, you are changing things all the time, a tuner can be a convenient way to quickly realize an aribtrary matching network. I am always fiddling around with things, so for me, the tuner is a very useful tool. Manual antenna tuners are very cheap when you buy them used and they are simple, so usually there isn't anything wrong with them, and if there is, it's generally easy to fix.


>>And even the 10db gain from your big linniker will not sound that dramatic to the other guy, he may not even notice much between you linear switched on or off, unless you tell him that is.<<

That is certainly true when signal-to-noise ratios are high (again talking to your buddies on 75SSB). I don't use my amplifier when signals are strong for that very reason (in that case it's hard to argue that its anything but a waste of electricity). I use mine when the other guy can't hear me very well without it. In that case that extra 10dB of gain makes the difference between good copy and NO copy. I do a lot of CW DXing on 160 meters, so 9 times out of 10, I need the amplifier to make the contact (and many times I don't make the contact even with the linear).

Thanks for your comments.

73, Mike W4EF......................
Reply to a comment by : N0EW on 2007-02-25

> And I still say using a tuner in your shack hooked to un-balanced line > (coax) is ABSURD! You are only fooling yourself and your radio. You are NOT > making your antenna work any better! This is one of my pet peeves, claiming that physics is some kind of underhanded trickery! Saying a "tuner" is able to "trick" another device -generally offered in terms of impedance matching- is like saying your power supply is "tricking" your transceiver into "thinking" it is getting something close to 12- or 13-volts dc, as opposed to the 120-volts ac that is coming out of the wall socket. It is madness! Now I'm all for trying to paint simple pictures to express basic ideas, I in fact do it quite often. However, at some point such short cuts actually create barriers to understanding. I feel this is one such example. Now, if we are all lucky, my computer will succeed in "tricking" the various other computers along the pathway between my home and the eHam server, and you will all get to read these words of wisdom, without which you would surely feel deprived (ya! right!) Heheh... Erik n0ew
Reply to a comment by : KD2BD on 2007-02-25

W4LGH wrote: > And I still say using a tuner in your shack hooked to un-balanced line > (coax) is ABSURD! You are only fooling yourself and your radio. You are NOT > making your antenna work any better! Not true. The tuner not only matching impedances, it also re-directs the reflected power in the transmission line back towards the antenna in the proper phase so it can be radiated along with the incident, forward power. The higher the SWR on the line, the more times the RF energy must bounce back and forth on the line before it is completely radiated by the antenna. Therefore, a low-loss line is very desirable under these circumstances. The tuner does not "fool" the transmitter or the operator. The voltage/current/power at the antenna terminals will, in fact, peak when the tuner is properly adjusted for the reasons stated above, and because the antenna SYSTEM has been brought into resonance, impedance matched to the transmitter, and tuned for maximum power transfer. Whether the tuner is located at the antenna, 5 feet down the line, 15 feet down the line, or 150 feet down the line doesn't matter (except for some additional feedline loss in the latter case because of the multiple bounces the RF must undergo on the line before every drop of RF is finally radiated by the antenna). While it may be difficult to remotely measure the voltage at the antenna terminals while you're adjusting the tuner, a simple relative field strength meter described in any edition of the ARRL Handbook would easily prove what I and others are saying is true. (And maximum radiated field strength is really what we're after, isn't it?) > Put the tuner/matching network @ the antenna, then you are doing something. This is a better approach, but it merely eliminates the additional loss incurred in the feedline due to the high VSWR. The Handbook illustrates how significant this additional loss is in the form of a series of curves. > Feed a dippole with open lead (balanced line) into your shack to a tuner, > then you are tuning the feed line into the antenna, and that works somewhat. "Tuning the feed line into the antenna"? What does THAT mean? :-) VSWR means the same thing and has the same effects whether the feedline is balanced or not. The only reason this approach works slightly better over RG/8 is because open wire line has very loss to begin with, and the additional transmission line loss produced by high VSWR is fairly insignificant to most HF operations. The wide spacing between the conductors yields a high breakdown voltage as well. > Install a resonant antenna system fed with low loss coax and now you > really have something nice, and its done the right way. Agreed. However, the approaches described earlier aren't nearly as bad as you're making them out to be. 73, de John, KD2BD
Reply to a comment by : N1EY on 2007-02-22

How is a vertical dipole more efficient? It would only depend on the ground system and the counterpoise. A regular vertical with a good ground and counterpoise is going to have positive dbI. A vertical dipole might not. N1EY
Reply to a comment by : ONAIR on 2007-02-22

Interesting point. So a resonant vertical dipole would then be a lot more efficient than a vertical that you would need to tune?
KC8QFP2007-02-25
RE: Benchmarks
The main reason that I am not into linears is safety. Those KILLER WATTS are very dangerous, even 200 watts of RF can really kick your ass! I am an accident waiting to happen (poor eyesight). And the bang for the buck is not that big of a deal even for 10db gain. I am far more comfortable with under 100 watts, and it is far more thrilling to talk somewhere around this world with less power than it is to contest with a big bad linniker.

I admit that I have an MFJ (I think it is a cheapie 941b versa tuner or something like that). I used to have a Dentron Jr. I just never like the damn things, something more to fuss with. It certainly does not make things better for the guy at the other side of the QSO. I also have a Hustler 5BTV (yes those damn traps and a virtical). The tuner goes with the vertical - YUK! I'm not made of money, and that was pretty much given to me, it's lossy, but better than nothing.

But when the weather gets better here in northern Ohio, I plan to make for a much better antenna system for my TenTec. Then kiss that Hustler and MFJ matchbox GOODBYE! I plan to use a few bands, and don't really care about having antennaes for all the bands on the rig. So a few wire antennaes will do fine, and I don't have to invest a lotta $$$ to get the job done, and done right!

I'll probably have just as much fun with my cheapie station as the guys that spend megabucks for their toys. That Tentec does pretty damn good with the shitty tuner and Hustler. I can't wait to connect it to a decent antenna! I'd buy one, but most commercial Cushcraft, MFJ, Gap, Hygain, etc. etc. etc. either use traps or cost a lot of $$$. The more they cost, the more skeptical I am about them. For a low band vertical (only because there are so many hams that use them on HF do to small yards), I like the Gap. I don't want to get into a beam, like I said, the small amount of gain is not worth the expense and fussin with a tower and rotor. My elmer is a SK, and I could probably get his old Mosley tri-bander and Ham IV rotor free for taking it down. Too much trouble for a trap monster. He did better with his dipole too! (his coax was old) Go figure? I wish I had his Drake TR3, nice rig. Somebody else got that gem.

So I think you get my point, for some it may be worth it to them to waste watts on tuners and traps. But not for me. If I am gonna blow a lotta money to talk on a radio, I will go for a really nice reciever. I never got to try a Drake TR7 or even the newer 8. I had a TR4 that was all screwed up (from a hamfest). I traded that for packet (MFJ 1278) a longtime ago. I know that TR3 was sweeeeet! I had the nip rigs, no biggie for me, but the Kenwood TS520 could hear pretty good to me. I never had any of the fancy big $$$ rigs. Give a good receiver a good antenna, much easier than all that other junk! 200 watts is adequite for me. Don't need to crunch specs (alligator) and spend megabucksto enjoy talkin' on a radidio!

Cheerz, Don
Reply to a comment by : KC8QFP on 2007-02-25

My ears cannot tell the difference between a few db loss at the other end, that's my point. Some people feel they gotta spend a shitload of $$$ on tuners, feedline, traps, linears, and so on and it is not worth it, the guy at the other end will not be able to HEAR the difference between all that junk! I was also talking about a low power linniker as in 500 watts. If you are using a 2KW linear, I would hope that you have the sense to have it connected to a very well matched antenna for goodnes sakes! Yes, there is a considerable db gain in such an amplifier. But I would think you had the sense to avoid a matchbox all the more with that kind of RF energy! Stray RF can be extreemly dangerous! Traps can explode, tuners arc, and shit gets mighty HOT with RF at even 1KW! But since you are a firm believer in traps and tuners, at least you won't need a microwave oven in your ham shack to keep your coffee and donuts warm. I simply agree with Alan, you are better off without them (tuner/traps), even with a linear, better to a matched antenna! And even the 10db gain from your big linniker will not sound that dramatic to the other guy, he may not even notice much between you linear switched on or off, unless you tell him that is.
Reply to a comment by : W4EF on 2007-02-25

KC8QFP wrote: >>My ears tell me more than numbers!<< I would agree that ears are very good for evaluating microphones, but please tell us how you measure tuner loss, antenna efficiency, or feedline loss to fractional dB accuracy using your ears? Must be some pretty impressive ears. >>The few db gain you get from a linniker is lost elsewhere, dare I repeat myself. Too many alligators out there crunching numbers.<< Really!! I don't know about your "linniker" but my amplifier gives me about 10dB of gain. If you can find 10dB of loss in my antenna system that is easily removed, then I will concede your argument. I can guarantee that you won't find that much in the antenna tuner (~0.5dB) nor the feedline (~0.2dB). You might find 6dB of loss in the ground system of my 160 antenna, but doing a good job of fixing that would require me to purchase about $2 million in real estate (the homes surrounding me), and then rent a Cat D9 to level the homes. Trust me, I would love to do that, but I figured the $400 I spent on a used Drake L-7 amplifier (~10dB of transmit gain) was a more cost effective way to make up that 6dB of ground system loss than destroying $2 million worth of real estate that I don't even own. 73, Mike W4EF...............
Reply to a comment by : KC8QFP on 2007-02-25

The TWO best investments would be the antenna and the receiver. Not the matchbox, microphone, and linear! A little known secret, IMO, the 2$ eletret condensor mic element (as from Rad Shaft) isn't much different than what you'll find in a Yaesu or Icom desk mic! And you'll sound like crap on sideband regardless of how good your mic is. My ears tell me more than numbers! If you want a really good mic, invest in an ElectroVoice RE-20 broadcast microphone, then do AM! But you better learn about phantom power condensor mics first! The few db gain you get from a linniker is lost elsewhere, dare I repeat myself. Too many alligators out there crunching numbers.
Reply to a comment by : KC8QFP on 2007-02-25

One thing that really gets me is how the number crunchers end up using traps, tuners, randumb wire antennaes, and such which pretty much makes their numbers moot! All that $$$ and talk to waste power! Well it keeps MFJ and AES happy, they are counting the numbers$$$ Get out your calculators (and slide rules for the OF's), do the math, talk it over with other walking calculators, then take your wallets to the candy store and pay lots of extra cold hard cash for traps, tuners, and fancy wire. Like I said, the 3 db gain (if that is for real) is lost in the traps, 200+ feet of wire, and most of all through the tuner. Enjoy your spec sheets! Don
Reply to a comment by : W4EF on 2007-02-25

"Free-space path-loss" is indeed a fictious quantity used in link budget calculations to account for the fact that for a given quantity of receive antenna gain, the "capture area" or "effective aperture" of that receive antenna goes down with the square of frequency. IOW, a receive antenna that has 10dBi of gain at 10MHz will capture 100 times the energy (at 10 MHz) than a receive antenna that has 10dBi gain at 100 MHz will capture (at 100 MHz). This makes sense since a 10dBi antenna at 10 MHz is generally a lot bigger than a 10dBi antenna at 100 MHz. If free-space link budgets used effective aperture for the specifying the receive antenna gain instead of gain in dBi, then there would be no-need for a frequency dependent free-space path loss term. For non-free space links, however, there may in fact be a frequency dependent path loss term needed in the link calculation. Unlike free-space path loss which is a misnomer since there is no such thing a free-space path-loss (well there is, but its always 0dB), the non-free space loss loss term actually refers the physical loss characteristics of the path. 73, Mike W4EF.................
Reply to a comment by : W4EF on 2007-02-25

W4LGH >>And I still say using a tuner in your shack hooked to un-balanced line (coax) is ABSURD! You are only fooling yourself and your radio. You are NOT making your antenna work any better!<< A long time ago (back when I was a real W4), I had tuning network at the feedpoint of my 160 meter Marconi. I didn't have servo's on the matching components, so when I wanted to QSY across a significant frequency range, I had to walk outside (sometimes in the rain) to adjust the matching network. Now that I am a fake W4 (/W6 in Southern California), I match my 160 meter inverted-L from the shack through about 30 feet of low-loss coax. This makes QSYing much easier (especially when it's raining). In my particular case, there is a very slight compromise (~0.2dB loss) associated with matching the antenna from the shack through the coax. The convenience, however, of matching from the shack far outways the miniscule performance hit. Perhaps in your view of things that makes me an "F#%king idiot", but in my view I'd like to think that I am just exercising good engineering judgement by making a sensible tradeoff (convenience vs. 0.2dB extra loss). And anyway, the "system", is in fact resonant, even if the antenna by itself is not. 73, Mike W4EF.........
Reply to a comment by : KD2BD on 2007-02-25

W8JI wrote: > Capture area must be a Ham term. Not true. It is an antenna engineering term that has been around for decades. See the references and the discussion in my post above. > All that aside, it is virtually meaningless for determining how good an antenna is for receiving. Not true. Effective capture area multiplied times received power density (in watts per square meter) yields the power delivered by a receiving antenna into a matched load. Ohm's Law will provide the terminal voltage knowing its impedance. This is a VERY important piece of information when designing a communications system. 73, de John, KD2BD
Reply to a comment by : W8JI on 2007-02-23

"Capture area" really has little to do with physical size of the antenna. It relates solidly only to frequency and gain. The somewhat questionable exception is in an aperture antenna like a horn or parabolic reflector antenna. Even in these special aperture based antennas the effective aperture differs significantly from actual aperture, ranging from 45% to 75% with 65% being considered a very good design. If I have two exactly identical antennas in every way except I make one from a more lossy material, the lossy antenna will have less "capture area". Effective aperture is nothing more than a way we can correct for the change in wavelength and gain of antennas. If I have two antennas 500 feet apart, they are twice as far apart in terms of the wavelength as frequency is doubled. Capture area must be a Ham term. All that aside, it is virtually meaningless for determining how good an antenna is for receiving. Once the system limits on external noise concerns about absolute power or effective aperture are pointless. The only thing that matters is the ratio of desired signal to undesired signal received, and that has nothing to do with effective aperture or gain. It is all about pattern shape, not pattern size.
Reply to a comment by : KY1V on 2007-02-23

>RE: Benchmarks Reply by KY1V on February 23, 2007 Mail this to a friend! Yeah, that's how I want to spend my weekends, picking through garbage for antenna wire... Good Grief! David ~ KY1V< ::I plan to spend my retirement dumpster diving, because I didn't get much of this earlier. :-) WB2WIK/6 ------------------------ Maybe you can find a hardly used CapcitiveReciprocityMicroHomeBrewCoaxialDynamic Antenna wire in one of those and talk to me in Jamaica! I think I can hear you on your dummy load! David ~ KY1V
Reply to a comment by : WB2WIK on 2007-02-23

>RE: Benchmarks Reply by KY1V on February 23, 2007 Mail this to a friend! Yeah, that's how I want to spend my weekends, picking through garbage for antenna wire... Good Grief! David ~ KY1V< ::I plan to spend my retirement dumpster diving, because I didn't get much of this earlier. :-) WB2WIK/6
Reply to a comment by : KY1V on 2007-02-23

Yeah, that's how I want to spend my weekends, picking through garbage for antenna wire... Good Grief! David ~ KY1V
Reply to a comment by : N0AH on 2007-02-23

I say plug in coax to radio. Then feed coax to antenna. Check for any potetial problems. Have fun...bench that-
N3OX2007-02-25
RE: Benchmarks
N0EW, you have a point about needing too many antennas to have a resonant one for every band... that's why I use matching networks here. It would be silly for me to have a seperate vertical for 160m, 80m, 40m, and 30m when it can all be rolled into one antenna. In my case, having a multiple-resonant antenna with traps is impossible, because I couldn't live with the weight of traps on my fiberglass support pole.

So, I stick a matching network for each band at the base and off I go. No need to use a different antenna for each... that would get me nothing but an impossible-to-navigate yard.

Same thing with my 20m delta loop. Why build another one for 17m when all I have to do is stick a couple of little L-networks at the feedpoint and use a relay to switch back and forth between bands.

A 20m delta loop used on 17m has more gain than a 17m delta loop anyway!

Dan
Reply to a comment by : N3OX on 2007-02-25

KC8QFP says: "I suppose that all this STRAY RF bouncing all over the place - the coax, tuner, transmitter, ground wireing, tower, YOU, and who knows where else - eventually finds its way to and out of a randumb length antenna?" All I have to say is "huh?" - - - - - - I will direct this one at the sky instead of at anyone in particular... but the adjective that goes with an antenna that shows a purely resistive feedpoint impedance at some frequency is "resonant" not "resonate." I'm gonna start an antenna company called Resonate and collect royalties from everyone who mentions a "Resonate dipole (TM)" Not trying to be mean, just makes me wince every time I see it. Dan
Reply to a comment by : N0EW on 2007-02-25

> And I still say using a tuner in your shack hooked to un-balanced line > (coax) is ABSURD! You are only fooling yourself and your radio. You are NOT > making your antenna work any better! This is one of my pet peeves, claiming that physics is some kind of underhanded trickery! Saying a "tuner" is able to "trick" another device -generally offered in terms of impedance matching- is like saying your power supply is "tricking" your transceiver into "thinking" it is getting something close to 12- or 13-volts dc, as opposed to the 120-volts ac that is coming out of the wall socket. It is madness! Now I'm all for trying to paint simple pictures to express basic ideas, I in fact do it quite often. However, at some point such short cuts actually create barriers to understanding. I feel this is one such example. Now, if we are all lucky, my computer will succeed in "tricking" the various other computers along the pathway between my home and the eHam server, and you will all get to read these words of wisdom, without which you would surely feel deprived (ya! right!) Heheh... Erik n0ew
Reply to a comment by : KD2BD on 2007-02-25

W4LGH wrote: > And I still say using a tuner in your shack hooked to un-balanced line > (coax) is ABSURD! You are only fooling yourself and your radio. You are NOT > making your antenna work any better! Not true. The tuner not only matching impedances, it also re-directs the reflected power in the transmission line back towards the antenna in the proper phase so it can be radiated along with the incident, forward power. The higher the SWR on the line, the more times the RF energy must bounce back and forth on the line before it is completely radiated by the antenna. Therefore, a low-loss line is very desirable under these circumstances. The tuner does not "fool" the transmitter or the operator. The voltage/current/power at the antenna terminals will, in fact, peak when the tuner is properly adjusted for the reasons stated above, and because the antenna SYSTEM has been brought into resonance, impedance matched to the transmitter, and tuned for maximum power transfer. Whether the tuner is located at the antenna, 5 feet down the line, 15 feet down the line, or 150 feet down the line doesn't matter (except for some additional feedline loss in the latter case because of the multiple bounces the RF must undergo on the line before every drop of RF is finally radiated by the antenna). While it may be difficult to remotely measure the voltage at the antenna terminals while you're adjusting the tuner, a simple relative field strength meter described in any edition of the ARRL Handbook would easily prove what I and others are saying is true. (And maximum radiated field strength is really what we're after, isn't it?) > Put the tuner/matching network @ the antenna, then you are doing something. This is a better approach, but it merely eliminates the additional loss incurred in the feedline due to the high VSWR. The Handbook illustrates how significant this additional loss is in the form of a series of curves. > Feed a dippole with open lead (balanced line) into your shack to a tuner, > then you are tuning the feed line into the antenna, and that works somewhat. "Tuning the feed line into the antenna"? What does THAT mean? :-) VSWR means the same thing and has the same effects whether the feedline is balanced or not. The only reason this approach works slightly better over RG/8 is because open wire line has very loss to begin with, and the additional transmission line loss produced by high VSWR is fairly insignificant to most HF operations. The wide spacing between the conductors yields a high breakdown voltage as well. > Install a resonant antenna system fed with low loss coax and now you > really have something nice, and its done the right way. Agreed. However, the approaches described earlier aren't nearly as bad as you're making them out to be. 73, de John, KD2BD
Reply to a comment by : N1EY on 2007-02-22

How is a vertical dipole more efficient? It would only depend on the ground system and the counterpoise. A regular vertical with a good ground and counterpoise is going to have positive dbI. A vertical dipole might not. N1EY
Reply to a comment by : ONAIR on 2007-02-22

Interesting point. So a resonant vertical dipole would then be a lot more efficient than a vertical that you would need to tune?
N3OX2007-02-25
RE: Benchmarks
KC8QFP says: "I suppose that all this STRAY RF bouncing all over the place - the coax, tuner, transmitter, ground wireing, tower, YOU, and who knows where else - eventually finds its way to and out of a randumb length antenna?"

All I have to say is "huh?"

- - - - - -

I will direct this one at the sky instead of at anyone in particular... but the adjective that goes with an antenna that shows a purely resistive feedpoint impedance at some frequency is "resonant" not "resonate."

I'm gonna start an antenna company called Resonate and collect royalties from everyone who mentions a "Resonate dipole (TM)"

Not trying to be mean, just makes me wince every time I see it.

Dan
Reply to a comment by : N0EW on 2007-02-25

> And I still say using a tuner in your shack hooked to un-balanced line > (coax) is ABSURD! You are only fooling yourself and your radio. You are NOT > making your antenna work any better! This is one of my pet peeves, claiming that physics is some kind of underhanded trickery! Saying a "tuner" is able to "trick" another device -generally offered in terms of impedance matching- is like saying your power supply is "tricking" your transceiver into "thinking" it is getting something close to 12- or 13-volts dc, as opposed to the 120-volts ac that is coming out of the wall socket. It is madness! Now I'm all for trying to paint simple pictures to express basic ideas, I in fact do it quite often. However, at some point such short cuts actually create barriers to understanding. I feel this is one such example. Now, if we are all lucky, my computer will succeed in "tricking" the various other computers along the pathway between my home and the eHam server, and you will all get to read these words of wisdom, without which you would surely feel deprived (ya! right!) Heheh... Erik n0ew
Reply to a comment by : KD2BD on 2007-02-25

W4LGH wrote: > And I still say using a tuner in your shack hooked to un-balanced line > (coax) is ABSURD! You are only fooling yourself and your radio. You are NOT > making your antenna work any better! Not true. The tuner not only matching impedances, it also re-directs the reflected power in the transmission line back towards the antenna in the proper phase so it can be radiated along with the incident, forward power. The higher the SWR on the line, the more times the RF energy must bounce back and forth on the line before it is completely radiated by the antenna. Therefore, a low-loss line is very desirable under these circumstances. The tuner does not "fool" the transmitter or the operator. The voltage/current/power at the antenna terminals will, in fact, peak when the tuner is properly adjusted for the reasons stated above, and because the antenna SYSTEM has been brought into resonance, impedance matched to the transmitter, and tuned for maximum power transfer. Whether the tuner is located at the antenna, 5 feet down the line, 15 feet down the line, or 150 feet down the line doesn't matter (except for some additional feedline loss in the latter case because of the multiple bounces the RF must undergo on the line before every drop of RF is finally radiated by the antenna). While it may be difficult to remotely measure the voltage at the antenna terminals while you're adjusting the tuner, a simple relative field strength meter described in any edition of the ARRL Handbook would easily prove what I and others are saying is true. (And maximum radiated field strength is really what we're after, isn't it?) > Put the tuner/matching network @ the antenna, then you are doing something. This is a better approach, but it merely eliminates the additional loss incurred in the feedline due to the high VSWR. The Handbook illustrates how significant this additional loss is in the form of a series of curves. > Feed a dippole with open lead (balanced line) into your shack to a tuner, > then you are tuning the feed line into the antenna, and that works somewhat. "Tuning the feed line into the antenna"? What does THAT mean? :-) VSWR means the same thing and has the same effects whether the feedline is balanced or not. The only reason this approach works slightly better over RG/8 is because open wire line has very loss to begin with, and the additional transmission line loss produced by high VSWR is fairly insignificant to most HF operations. The wide spacing between the conductors yields a high breakdown voltage as well. > Install a resonant antenna system fed with low loss coax and now you > really have something nice, and its done the right way. Agreed. However, the approaches described earlier aren't nearly as bad as you're making them out to be. 73, de John, KD2BD
Reply to a comment by : N1EY on 2007-02-22

How is a vertical dipole more efficient? It would only depend on the ground system and the counterpoise. A regular vertical with a good ground and counterpoise is going to have positive dbI. A vertical dipole might not. N1EY
Reply to a comment by : ONAIR on 2007-02-22

Interesting point. So a resonant vertical dipole would then be a lot more efficient than a vertical that you would need to tune?
N0EW2007-02-25
RE: Benchmarks
> And I still say using a tuner in your shack hooked to un-balanced line
> (coax) is ABSURD! You are only fooling yourself and your radio. You are NOT
> making your antenna work any better!

This is one of my pet peeves, claiming that physics is some kind of underhanded trickery!

Saying a "tuner" is able to "trick" another device -generally offered in terms of impedance matching- is like saying your power supply is "tricking" your transceiver into "thinking" it is getting something close to 12- or 13-volts dc, as opposed to the 120-volts ac that is coming out of the wall socket.

It is madness!

Now I'm all for trying to paint simple pictures to express basic ideas, I in fact do it quite often. However, at some point such short cuts actually create barriers to understanding. I feel this is one such example.

Now, if we are all lucky, my computer will succeed in "tricking" the various other computers along the pathway between my home and the eHam server, and you will all get to read these words of wisdom, without which you would surely feel deprived (ya! right!)

Heheh... Erik n0ew
Reply to a comment by : KD2BD on 2007-02-25

W4LGH wrote: > And I still say using a tuner in your shack hooked to un-balanced line > (coax) is ABSURD! You are only fooling yourself and your radio. You are NOT > making your antenna work any better! Not true. The tuner not only matching impedances, it also re-directs the reflected power in the transmission line back towards the antenna in the proper phase so it can be radiated along with the incident, forward power. The higher the SWR on the line, the more times the RF energy must bounce back and forth on the line before it is completely radiated by the antenna. Therefore, a low-loss line is very desirable under these circumstances. The tuner does not "fool" the transmitter or the operator. The voltage/current/power at the antenna terminals will, in fact, peak when the tuner is properly adjusted for the reasons stated above, and because the antenna SYSTEM has been brought into resonance, impedance matched to the transmitter, and tuned for maximum power transfer. Whether the tuner is located at the antenna, 5 feet down the line, 15 feet down the line, or 150 feet down the line doesn't matter (except for some additional feedline loss in the latter case because of the multiple bounces the RF must undergo on the line before every drop of RF is finally radiated by the antenna). While it may be difficult to remotely measure the voltage at the antenna terminals while you're adjusting the tuner, a simple relative field strength meter described in any edition of the ARRL Handbook would easily prove what I and others are saying is true. (And maximum radiated field strength is really what we're after, isn't it?) > Put the tuner/matching network @ the antenna, then you are doing something. This is a better approach, but it merely eliminates the additional loss incurred in the feedline due to the high VSWR. The Handbook illustrates how significant this additional loss is in the form of a series of curves. > Feed a dippole with open lead (balanced line) into your shack to a tuner, > then you are tuning the feed line into the antenna, and that works somewhat. "Tuning the feed line into the antenna"? What does THAT mean? :-) VSWR means the same thing and has the same effects whether the feedline is balanced or not. The only reason this approach works slightly better over RG/8 is because open wire line has very loss to begin with, and the additional transmission line loss produced by high VSWR is fairly insignificant to most HF operations. The wide spacing between the conductors yields a high breakdown voltage as well. > Install a resonant antenna system fed with low loss coax and now you > really have something nice, and its done the right way. Agreed. However, the approaches described earlier aren't nearly as bad as you're making them out to be. 73, de John, KD2BD
Reply to a comment by : N1EY on 2007-02-22

How is a vertical dipole more efficient? It would only depend on the ground system and the counterpoise. A regular vertical with a good ground and counterpoise is going to have positive dbI. A vertical dipole might not. N1EY
Reply to a comment by : ONAIR on 2007-02-22

Interesting point. So a resonant vertical dipole would then be a lot more efficient than a vertical that you would need to tune?
KC8QFP2007-02-25
RE: Benchmarks
My ears cannot tell the difference between a few db loss at the other end, that's my point. Some people feel they gotta spend a shitload of $$$ on tuners, feedline, traps, linears, and so on and it is not worth it, the guy at the other end will not be able to HEAR the difference between all that junk! I was also talking about a low power linniker as in 500 watts. If you are using a 2KW linear, I would hope that you have the sense to have it connected to a very well matched antenna for goodnes sakes! Yes, there is a considerable db gain in such an amplifier. But I would think you had the sense to avoid a matchbox all the more with that kind of RF energy! Stray RF can be extreemly dangerous! Traps can explode, tuners arc, and shit gets mighty HOT with RF at even 1KW! But since you are a firm believer in traps and tuners, at least you won't need a microwave oven in your ham shack to keep your coffee and donuts warm. I simply agree with Alan, you are better off without them (tuner/traps), even with a linear, better to a matched antenna! And even the 10db gain from your big linniker will not sound that dramatic to the other guy, he may not even notice much between you linear switched on or off, unless you tell him that is.
Reply to a comment by : W4EF on 2007-02-25

KC8QFP wrote: >>My ears tell me more than numbers!<< I would agree that ears are very good for evaluating microphones, but please tell us how you measure tuner loss, antenna efficiency, or feedline loss to fractional dB accuracy using your ears? Must be some pretty impressive ears. >>The few db gain you get from a linniker is lost elsewhere, dare I repeat myself. Too many alligators out there crunching numbers.<< Really!! I don't know about your "linniker" but my amplifier gives me about 10dB of gain. If you can find 10dB of loss in my antenna system that is easily removed, then I will concede your argument. I can guarantee that you won't find that much in the antenna tuner (~0.5dB) nor the feedline (~0.2dB). You might find 6dB of loss in the ground system of my 160 antenna, but doing a good job of fixing that would require me to purchase about $2 million in real estate (the homes surrounding me), and then rent a Cat D9 to level the homes. Trust me, I would love to do that, but I figured the $400 I spent on a used Drake L-7 amplifier (~10dB of transmit gain) was a more cost effective way to make up that 6dB of ground system loss than destroying $2 million worth of real estate that I don't even own. 73, Mike W4EF...............
Reply to a comment by : KC8QFP on 2007-02-25

The TWO best investments would be the antenna and the receiver. Not the matchbox, microphone, and linear! A little known secret, IMO, the 2$ eletret condensor mic element (as from Rad Shaft) isn't much different than what you'll find in a Yaesu or Icom desk mic! And you'll sound like crap on sideband regardless of how good your mic is. My ears tell me more than numbers! If you want a really good mic, invest in an ElectroVoice RE-20 broadcast microphone, then do AM! But you better learn about phantom power condensor mics first! The few db gain you get from a linniker is lost elsewhere, dare I repeat myself. Too many alligators out there crunching numbers.
Reply to a comment by : KC8QFP on 2007-02-25

One thing that really gets me is how the number crunchers end up using traps, tuners, randumb wire antennaes, and such which pretty much makes their numbers moot! All that $$$ and talk to waste power! Well it keeps MFJ and AES happy, they are counting the numbers$$$ Get out your calculators (and slide rules for the OF's), do the math, talk it over with other walking calculators, then take your wallets to the candy store and pay lots of extra cold hard cash for traps, tuners, and fancy wire. Like I said, the 3 db gain (if that is for real) is lost in the traps, 200+ feet of wire, and most of all through the tuner. Enjoy your spec sheets! Don
Reply to a comment by : W4EF on 2007-02-25

"Free-space path-loss" is indeed a fictious quantity used in link budget calculations to account for the fact that for a given quantity of receive antenna gain, the "capture area" or "effective aperture" of that receive antenna goes down with the square of frequency. IOW, a receive antenna that has 10dBi of gain at 10MHz will capture 100 times the energy (at 10 MHz) than a receive antenna that has 10dBi gain at 100 MHz will capture (at 100 MHz). This makes sense since a 10dBi antenna at 10 MHz is generally a lot bigger than a 10dBi antenna at 100 MHz. If free-space link budgets used effective aperture for the specifying the receive antenna gain instead of gain in dBi, then there would be no-need for a frequency dependent free-space path loss term. For non-free space links, however, there may in fact be a frequency dependent path loss term needed in the link calculation. Unlike free-space path loss which is a misnomer since there is no such thing a free-space path-loss (well there is, but its always 0dB), the non-free space loss loss term actually refers the physical loss characteristics of the path. 73, Mike W4EF.................
Reply to a comment by : W4EF on 2007-02-25

W4LGH >>And I still say using a tuner in your shack hooked to un-balanced line (coax) is ABSURD! You are only fooling yourself and your radio. You are NOT making your antenna work any better!<< A long time ago (back when I was a real W4), I had tuning network at the feedpoint of my 160 meter Marconi. I didn't have servo's on the matching components, so when I wanted to QSY across a significant frequency range, I had to walk outside (sometimes in the rain) to adjust the matching network. Now that I am a fake W4 (/W6 in Southern California), I match my 160 meter inverted-L from the shack through about 30 feet of low-loss coax. This makes QSYing much easier (especially when it's raining). In my particular case, there is a very slight compromise (~0.2dB loss) associated with matching the antenna from the shack through the coax. The convenience, however, of matching from the shack far outways the miniscule performance hit. Perhaps in your view of things that makes me an "F#%king idiot", but in my view I'd like to think that I am just exercising good engineering judgement by making a sensible tradeoff (convenience vs. 0.2dB extra loss). And anyway, the "system", is in fact resonant, even if the antenna by itself is not. 73, Mike W4EF.........
Reply to a comment by : KD2BD on 2007-02-25

W8JI wrote: > Capture area must be a Ham term. Not true. It is an antenna engineering term that has been around for decades. See the references and the discussion in my post above. > All that aside, it is virtually meaningless for determining how good an antenna is for receiving. Not true. Effective capture area multiplied times received power density (in watts per square meter) yields the power delivered by a receiving antenna into a matched load. Ohm's Law will provide the terminal voltage knowing its impedance. This is a VERY important piece of information when designing a communications system. 73, de John, KD2BD
Reply to a comment by : W8JI on 2007-02-23

"Capture area" really has little to do with physical size of the antenna. It relates solidly only to frequency and gain. The somewhat questionable exception is in an aperture antenna like a horn or parabolic reflector antenna. Even in these special aperture based antennas the effective aperture differs significantly from actual aperture, ranging from 45% to 75% with 65% being considered a very good design. If I have two exactly identical antennas in every way except I make one from a more lossy material, the lossy antenna will have less "capture area". Effective aperture is nothing more than a way we can correct for the change in wavelength and gain of antennas. If I have two antennas 500 feet apart, they are twice as far apart in terms of the wavelength as frequency is doubled. Capture area must be a Ham term. All that aside, it is virtually meaningless for determining how good an antenna is for receiving. Once the system limits on external noise concerns about absolute power or effective aperture are pointless. The only thing that matters is the ratio of desired signal to undesired signal received, and that has nothing to do with effective aperture or gain. It is all about pattern shape, not pattern size.
Reply to a comment by : KY1V on 2007-02-23

>RE: Benchmarks Reply by KY1V on February 23, 2007 Mail this to a friend! Yeah, that's how I want to spend my weekends, picking through garbage for antenna wire... Good Grief! David ~ KY1V< ::I plan to spend my retirement dumpster diving, because I didn't get much of this earlier. :-) WB2WIK/6 ------------------------ Maybe you can find a hardly used CapcitiveReciprocityMicroHomeBrewCoaxialDynamic Antenna wire in one of those and talk to me in Jamaica! I think I can hear you on your dummy load! David ~ KY1V
Reply to a comment by : WB2WIK on 2007-02-23

>RE: Benchmarks Reply by KY1V on February 23, 2007 Mail this to a friend! Yeah, that's how I want to spend my weekends, picking through garbage for antenna wire... Good Grief! David ~ KY1V< ::I plan to spend my retirement dumpster diving, because I didn't get much of this earlier. :-) WB2WIK/6
Reply to a comment by : KY1V on 2007-02-23

Yeah, that's how I want to spend my weekends, picking through garbage for antenna wire... Good Grief! David ~ KY1V
Reply to a comment by : N0AH on 2007-02-23

I say plug in coax to radio. Then feed coax to antenna. Check for any potetial problems. Have fun...bench that-
N0EW2007-02-25
RE: Benchmarks
KC8QFP, you may have a point. There just may be something about playing with a couple knobs that is in itself exciting. I'll bring this up at my next session ;) Hehehe...

Seriously, for me the fondness for transmatches generally falls into one of two categories:

1. Lack of land area for several resonate antennas for every band I like to play on. (After all, if you are going to be completely nuts about only using resonate antennas, you'll need more than one of them on every band, as the reactance will catch up to you as you digress from the single frequency for which it has been cut. Our totally obsessed friends will have to try to ignore the fact that a length of wire can only be truly resonate for a single frequency, and to be modulated to carry information, a greater width in their radiating signal is required; so for the purist there is no truly resonate antenna on this planet. At least not one that also transmits information. The rest of us will have to live with some compromise we are willing to suffer.)

2. Laziness. (Not much to rationalize here. I admit to caring less about how perfect my antenna system is radiating, than I am about jumping to a totally different band and rag chewing with someone for a while. Antenna systems are pretty forgiving in my opinion. You can make all kinds of things work as antennas and have a ton of fun talking to people.)

But now I'll never look at my transmatches knobs the same way again, nor take them for granted! Heheh.... Thanks (I think!)

Erik n0ew
Reply to a comment by : KC8QFP on 2007-02-25

IMO, Tuners are something that I'd rather do without. I'd like to do away with all the damn wire and the infamous matchbox for good! I don't understand why hams seem to like the darn things, maybe its the two big knobs to play with or something? I was thinking about setting up a shack like in a treehouse so I would not need the coax and matchbox. Then I could connect the antenna directly to my rig. Just call me Tarzan! Hi Hi! I don't know if it is Murphy's Law or what, but wire seems to always get all tangled up in a mess. It's worse than a garden hose! Just drop a wire on the floor, and it's a tangled mess of knots! All the wires on my confuser, my hifi system, TV/VCR, ham radio junk, PA system (for music), and the XMAS lights (don't forget the XMAS lights)! If it were to be a choice between a matched antenna or a matchbox, I go with the proper antenna hands down! As for benchmark numbers and specs vs actual performance, that is sort of like when you put up your antenna, avoid perfect weather, it doesn't work right, you have to put your antenna up when the weather is bad for it to work right! Cheerz! Don
Reply to a comment by : K9IUQ on 2007-02-25

W4GLH continues with his ranting: You made the statemant if tuners weren't any good, why did they put them in radios? K9IUQ says without vulgarity: Don't try to spin what I say, like you do with your comments. You want to quote what I say in past posts, fine. Since you don't seem to know how to use the find key in a Browser, here is what was said word for word NO SPIN and DIRECT QUOTES: .................. You W4LGH said: The idea of an antenna tuner hooked to an un-balanced line (coax) is absurd And K9IUQ replied : If this was true we wouldn't have built-in antenna tuners in our rigs. Stan K9IUQ
Reply to a comment by : W4LGH on 2007-02-25

Stan K9IUQ wrote.. But remember W4LGH said The idea of an antenna tuner hooked to an un-balanced line (coax) is absurd. And w4LGH said the reason they put antenna tuners in radios is so F#$KING IDIOTS like you will BUY THEM!! Statements like that I have a REAL problem with. ================ Why is that Stan, did you just learn you are a F#^KING IDIOT? Would you like some cheese to go with that wine? W4LGH said this and W4LGH said that... Jesus H Crist Stan...GROW UP! You made the statemant if tuners weren't any good, why did they put them in radios? If that statement is the basis of your logic, I rest my case! Damn I hate it when someone pushes me into calling them names, but I guess if the shoe fits...
Reply to a comment by : KC8QFP on 2007-02-25

There was a discussion on the ""Where will Ham Radio be 50 Years from Now"" about remote control wireless link between the shack and tower, i.e. no more need for feedline! You'd have a control head or PC remote that might use IR, low powered RF, or LASER to send signals to the tower for xceiver remote control, rotor, and perhaps even linear. So the tower would onlyneed a power source (120/220VAC 10g line). They do this with X-10 cameras, I was thinking about mounting one of those up on my tower. A simple way to direct couple the transmitter to the antenna! WOW! I sure would like to see TenTec or Drake make such a rig! YaeComWood already has full spectrum HT's, and TenTec has a PC controlled xceiver, with a few mods, this would be a great RC rig (if it has a USB port). I sure would like to see Drake get back into ham radio with such a rig! 73, Don
Reply to a comment by : K9IUQ on 2007-02-25

N3OX says It's also a *fact* that feeding a 20m dipole on 40m (14-j1000) through 30 feet of RG-8/X coax leads to 16dB feedline loss. Both of these cases (good coax, 5:1 SWR and common, cheap coax, 670:1 SWR) are encountered in amateur radio every day. The first one by people who are sensibly trying to stretch the frequency coverage of their 75m/80m dipole without complicated tricks at the antenna, and the latter by people who find that they can "find a match" on 40m with their 20m dipole and they can hear stations. In the former case, it's fine to use the tuner on your coax fed antenna. In the latter, it's absurd. ......................................................... I agree with you 100 percent, there is a time and place for an antenna tuner on coax. But remember W4LGH said The idea of an antenna tuner hooked to an un-balanced line (coax) is absurd. And w4LGH said the reason they put antenna tuners in radios is so F#$KING IDIOTS like you will BUY THEM!! Statements like that I have a REAL problem with. Stan K9IUQ
KC8QFP2007-02-25
RE: Benchmarks

<<<< Whether the tuner is located at the antenna, 5 feet down the line, 15 feet down the line, or 150 feet down the line doesn't matter (except for some additional feedline loss in the latter case because of the multiple bounces the RF must undergo on the line before every drop of RF is finally radiated by the antenna). >>>>


I suppose that all this STRAY RF bouncing all over the place - the coax, tuner, transmitter, ground wireing, tower, YOU, and who knows where else - eventually finds its way to and out of a randumb length antenna? GREAT! Use your gutters, same nonsense! Go buy yourself a $500.oo ""matchbox"" and enjoy it all you want! Good for you! IMO, wasted $$$ for wasted power!

And as for 80/160 meters, make a vertical with lots of traps to go with it! Don't forget a few radials underground and of course the ten foot ground-rod at its base. Paleeeeeeeeaze!

I'll admit that I would consider using a wasteful "matchbox" for 160m if I did not have the length to run the wire in my yard. But I would prefer having the tuner at the antenna feedpoint instead of in my shack. And that does not mean an auto tuner at considerable expense. A BALUN transformer, cap, or coil may do the job, depending on the location of the feedpoint. What I am saying here (anticipating your responses), a matchbox has variable caps and tapped (or variable) coil to handle multi-band mis-matches. For 160m, a fixed cap, coil, or transformer would be used for the working freq. Since it would not need adjustment, it need not be in the shack by your radio.

As I said, I think it is the two big knobs to play with! Waste your $$$, MFJ will be laughing all the way to the bank! And a ""tuner"" was an AM/FM receiver in your stereo system, or the guy that tuned accoustic pianees. EFJ called them "matchboxes", and MFJ calls them "tuners". And that's the name of that tune! Now I will go and tune my guitar with a tuner. Type tuner on ebay and see what you get a lot of, then type matchbox. Put that in your pipe and smoke it!

Don

PS: Yagi's and verticals are for VHF and above - and uusually without traps and tuners too. HF is for the wires all over the place!
Reply to a comment by : KD2BD on 2007-02-25

W4LGH wrote: > And I still say using a tuner in your shack hooked to un-balanced line > (coax) is ABSURD! You are only fooling yourself and your radio. You are NOT > making your antenna work any better! Not true. The tuner not only matching impedances, it also re-directs the reflected power in the transmission line back towards the antenna in the proper phase so it can be radiated along with the incident, forward power. The higher the SWR on the line, the more times the RF energy must bounce back and forth on the line before it is completely radiated by the antenna. Therefore, a low-loss line is very desirable under these circumstances. The tuner does not "fool" the transmitter or the operator. The voltage/current/power at the antenna terminals will, in fact, peak when the tuner is properly adjusted for the reasons stated above, and because the antenna SYSTEM has been brought into resonance, impedance matched to the transmitter, and tuned for maximum power transfer. Whether the tuner is located at the antenna, 5 feet down the line, 15 feet down the line, or 150 feet down the line doesn't matter (except for some additional feedline loss in the latter case because of the multiple bounces the RF must undergo on the line before every drop of RF is finally radiated by the antenna). While it may be difficult to remotely measure the voltage at the antenna terminals while you're adjusting the tuner, a simple relative field strength meter described in any edition of the ARRL Handbook would easily prove what I and others are saying is true. (And maximum radiated field strength is really what we're after, isn't it?) > Put the tuner/matching network @ the antenna, then you are doing something. This is a better approach, but it merely eliminates the additional loss incurred in the feedline due to the high VSWR. The Handbook illustrates how significant this additional loss is in the form of a series of curves. > Feed a dippole with open lead (balanced line) into your shack to a tuner, > then you are tuning the feed line into the antenna, and that works somewhat. "Tuning the feed line into the antenna"? What does THAT mean? :-) VSWR means the same thing and has the same effects whether the feedline is balanced or not. The only reason this approach works slightly better over RG/8 is because open wire line has very loss to begin with, and the additional transmission line loss produced by high VSWR is fairly insignificant to most HF operations. The wide spacing between the conductors yields a high breakdown voltage as well. > Install a resonant antenna system fed with low loss coax and now you > really have something nice, and its done the right way. Agreed. However, the approaches described earlier aren't nearly as bad as you're making them out to be. 73, de John, KD2BD
Reply to a comment by : N1EY on 2007-02-22

How is a vertical dipole more efficient? It would only depend on the ground system and the counterpoise. A regular vertical with a good ground and counterpoise is going to have positive dbI. A vertical dipole might not. N1EY
Reply to a comment by : ONAIR on 2007-02-22

Interesting point. So a resonant vertical dipole would then be a lot more efficient than a vertical that you would need to tune?
W4EF2007-02-25
RE: Benchmarks
KC8QFP wrote:

>>My ears tell me more than numbers!<<

I would agree that ears are very good for evaluating microphones, but please tell us how you measure tuner loss, antenna efficiency, or feedline loss to fractional dB accuracy using your ears? Must be some pretty impressive ears.

>>The few db gain you get from a linniker is lost elsewhere, dare I repeat myself. Too many alligators out there crunching numbers.<<

Really!! I don't know about your "linniker" but my amplifier gives me about 10dB of gain. If you can find 10dB of loss in my antenna system that is easily removed, then I will concede your argument. I can guarantee that you won't find that much in the antenna tuner (~0.5dB) nor the feedline (~0.2dB). You might find 6dB of loss in the ground system of my 160 antenna, but doing a good job of fixing that would require me to purchase about $2 million in real estate (the homes surrounding me), and then rent a Cat D9 to level the homes.

Trust me, I would love to do that, but I figured the $400 I spent on a used Drake L-7 amplifier (~10dB of transmit gain) was a more cost effective way to make up that 6dB of ground system loss than destroying $2 million worth of real estate that I don't even own.

73, Mike W4EF...............
Reply to a comment by : KC8QFP on 2007-02-25

The TWO best investments would be the antenna and the receiver. Not the matchbox, microphone, and linear! A little known secret, IMO, the 2$ eletret condensor mic element (as from Rad Shaft) isn't much different than what you'll find in a Yaesu or Icom desk mic! And you'll sound like crap on sideband regardless of how good your mic is. My ears tell me more than numbers! If you want a really good mic, invest in an ElectroVoice RE-20 broadcast microphone, then do AM! But you better learn about phantom power condensor mics first! The few db gain you get from a linniker is lost elsewhere, dare I repeat myself. Too many alligators out there crunching numbers.
Reply to a comment by : KC8QFP on 2007-02-25

One thing that really gets me is how the number crunchers end up using traps, tuners, randumb wire antennaes, and such which pretty much makes their numbers moot! All that $$$ and talk to waste power! Well it keeps MFJ and AES happy, they are counting the numbers$$$ Get out your calculators (and slide rules for the OF's), do the math, talk it over with other walking calculators, then take your wallets to the candy store and pay lots of extra cold hard cash for traps, tuners, and fancy wire. Like I said, the 3 db gain (if that is for real) is lost in the traps, 200+ feet of wire, and most of all through the tuner. Enjoy your spec sheets! Don
Reply to a comment by : W4EF on 2007-02-25

"Free-space path-loss" is indeed a fictious quantity used in link budget calculations to account for the fact that for a given quantity of receive antenna gain, the "capture area" or "effective aperture" of that receive antenna goes down with the square of frequency. IOW, a receive antenna that has 10dBi of gain at 10MHz will capture 100 times the energy (at 10 MHz) than a receive antenna that has 10dBi gain at 100 MHz will capture (at 100 MHz). This makes sense since a 10dBi antenna at 10 MHz is generally a lot bigger than a 10dBi antenna at 100 MHz. If free-space link budgets used effective aperture for the specifying the receive antenna gain instead of gain in dBi, then there would be no-need for a frequency dependent free-space path loss term. For non-free space links, however, there may in fact be a frequency dependent path loss term needed in the link calculation. Unlike free-space path loss which is a misnomer since there is no such thing a free-space path-loss (well there is, but its always 0dB), the non-free space loss loss term actually refers the physical loss characteristics of the path. 73, Mike W4EF.................
Reply to a comment by : W4EF on 2007-02-25

W4LGH >>And I still say using a tuner in your shack hooked to un-balanced line (coax) is ABSURD! You are only fooling yourself and your radio. You are NOT making your antenna work any better!<< A long time ago (back when I was a real W4), I had tuning network at the feedpoint of my 160 meter Marconi. I didn't have servo's on the matching components, so when I wanted to QSY across a significant frequency range, I had to walk outside (sometimes in the rain) to adjust the matching network. Now that I am a fake W4 (/W6 in Southern California), I match my 160 meter inverted-L from the shack through about 30 feet of low-loss coax. This makes QSYing much easier (especially when it's raining). In my particular case, there is a very slight compromise (~0.2dB loss) associated with matching the antenna from the shack through the coax. The convenience, however, of matching from the shack far outways the miniscule performance hit. Perhaps in your view of things that makes me an "F#%king idiot", but in my view I'd like to think that I am just exercising good engineering judgement by making a sensible tradeoff (convenience vs. 0.2dB extra loss). And anyway, the "system", is in fact resonant, even if the antenna by itself is not. 73, Mike W4EF.........
Reply to a comment by : KD2BD on 2007-02-25

W8JI wrote: > Capture area must be a Ham term. Not true. It is an antenna engineering term that has been around for decades. See the references and the discussion in my post above. > All that aside, it is virtually meaningless for determining how good an antenna is for receiving. Not true. Effective capture area multiplied times received power density (in watts per square meter) yields the power delivered by a receiving antenna into a matched load. Ohm's Law will provide the terminal voltage knowing its impedance. This is a VERY important piece of information when designing a communications system. 73, de John, KD2BD
Reply to a comment by : W8JI on 2007-02-23

"Capture area" really has little to do with physical size of the antenna. It relates solidly only to frequency and gain. The somewhat questionable exception is in an aperture antenna like a horn or parabolic reflector antenna. Even in these special aperture based antennas the effective aperture differs significantly from actual aperture, ranging from 45% to 75% with 65% being considered a very good design. If I have two exactly identical antennas in every way except I make one from a more lossy material, the lossy antenna will have less "capture area". Effective aperture is nothing more than a way we can correct for the change in wavelength and gain of antennas. If I have two antennas 500 feet apart, they are twice as far apart in terms of the wavelength as frequency is doubled. Capture area must be a Ham term. All that aside, it is virtually meaningless for determining how good an antenna is for receiving. Once the system limits on external noise concerns about absolute power or effective aperture are pointless. The only thing that matters is the ratio of desired signal to undesired signal received, and that has nothing to do with effective aperture or gain. It is all about pattern shape, not pattern size.
Reply to a comment by : KY1V on 2007-02-23

>RE: Benchmarks Reply by KY1V on February 23, 2007 Mail this to a friend! Yeah, that's how I want to spend my weekends, picking through garbage for antenna wire... Good Grief! David ~ KY1V< ::I plan to spend my retirement dumpster diving, because I didn't get much of this earlier. :-) WB2WIK/6 ------------------------ Maybe you can find a hardly used CapcitiveReciprocityMicroHomeBrewCoaxialDynamic Antenna wire in one of those and talk to me in Jamaica! I think I can hear you on your dummy load! David ~ KY1V
Reply to a comment by : WB2WIK on 2007-02-23

>RE: Benchmarks Reply by KY1V on February 23, 2007 Mail this to a friend! Yeah, that's how I want to spend my weekends, picking through garbage for antenna wire... Good Grief! David ~ KY1V< ::I plan to spend my retirement dumpster diving, because I didn't get much of this earlier. :-) WB2WIK/6
Reply to a comment by : KY1V on 2007-02-23

Yeah, that's how I want to spend my weekends, picking through garbage for antenna wire... Good Grief! David ~ KY1V
Reply to a comment by : N0AH on 2007-02-23

I say plug in coax to radio. Then feed coax to antenna. Check for any potetial problems. Have fun...bench that-
KD2BD2007-02-25
RE: Benchmarks
W4LGH wrote:

> And I still say using a tuner in your shack hooked to un-balanced line
> (coax) is ABSURD! You are only fooling yourself and your radio. You are NOT
> making your antenna work any better!

Not true. The tuner not only matching impedances, it also re-directs the reflected power in the transmission line back towards the antenna in the proper phase so it can be radiated along with the incident, forward power. The higher the SWR on the line, the more times the RF energy must bounce back and forth on the line before it is completely radiated by the antenna. Therefore, a low-loss line is very desirable under these circumstances.

The tuner does not "fool" the transmitter or the operator. The voltage/current/power at the antenna terminals will, in fact, peak when the tuner is properly adjusted for the reasons stated above, and because the antenna SYSTEM has been brought into resonance, impedance matched to the transmitter, and tuned for maximum power transfer.

Whether the tuner is located at the antenna, 5 feet down the line, 15 feet down the line, or 150 feet down the line doesn't matter (except for some additional feedline loss in the latter case because of the multiple bounces the RF must undergo on the line before every drop of RF is finally radiated by the antenna).

While it may be difficult to remotely measure the voltage at the antenna terminals while you're adjusting the tuner, a simple relative field strength meter described in any edition of the ARRL Handbook would easily prove what I and others are saying is true. (And maximum radiated field strength is really what we're after, isn't it?)

> Put the tuner/matching network @ the antenna, then you are doing something.

This is a better approach, but it merely eliminates the additional loss incurred in the feedline due to the high VSWR. The Handbook illustrates how significant this additional loss is in the form of a series of curves.

> Feed a dippole with open lead (balanced line) into your shack to a tuner,
> then you are tuning the feed line into the antenna, and that works somewhat.

"Tuning the feed line into the antenna"? What does THAT mean? :-)

VSWR means the same thing and has the same effects whether the feedline is balanced or not. The only reason this approach works slightly better over RG/8 is because open wire line has very loss to begin with, and the additional transmission line loss produced by high VSWR is fairly insignificant to most HF operations. The wide spacing between the conductors yields a high breakdown voltage as well.

> Install a resonant antenna system fed with low loss coax and now you
> really have something nice, and its done the right way.

Agreed. However, the approaches described earlier aren't nearly as bad as you're making them out to be.


73, de John, KD2BD
Reply to a comment by : N1EY on 2007-02-22

How is a vertical dipole more efficient? It would only depend on the ground system and the counterpoise. A regular vertical with a good ground and counterpoise is going to have positive dbI. A vertical dipole might not. N1EY
Reply to a comment by : ONAIR on 2007-02-22

Interesting point. So a resonant vertical dipole would then be a lot more efficient than a vertical that you would need to tune?
N3OX2007-02-25
RE: Benchmarks
"The few db gain you get from a linniker is lost elsewhere, dare I repeat myself."

Really? I use pretty efficient antennas. Of course, I don't have a linear but I'm going to build one for 80m/160m someday.

I use pretty good "matchboxes" too... I roll my own and put them right at the antenna... works great!

73,
Dan
Reply to a comment by : KC8QFP on 2007-02-25

The TWO best investments would be the antenna and the receiver. Not the matchbox, microphone, and linear! A little known secret, IMO, the 2$ eletret condensor mic element (as from Rad Shaft) isn't much different than what you'll find in a Yaesu or Icom desk mic! And you'll sound like crap on sideband regardless of how good your mic is. My ears tell me more than numbers! If you want a really good mic, invest in an ElectroVoice RE-20 broadcast microphone, then do AM! But you better learn about phantom power condensor mics first! The few db gain you get from a linniker is lost elsewhere, dare I repeat myself. Too many alligators out there crunching numbers.
Reply to a comment by : KC8QFP on 2007-02-25

One thing that really gets me is how the number crunchers end up using traps, tuners, randumb wire antennaes, and such which pretty much makes their numbers moot! All that $$$ and talk to waste power! Well it keeps MFJ and AES happy, they are counting the numbers$$$ Get out your calculators (and slide rules for the OF's), do the math, talk it over with other walking calculators, then take your wallets to the candy store and pay lots of extra cold hard cash for traps, tuners, and fancy wire. Like I said, the 3 db gain (if that is for real) is lost in the traps, 200+ feet of wire, and most of all through the tuner. Enjoy your spec sheets! Don
Reply to a comment by : W4EF on 2007-02-25

"Free-space path-loss" is indeed a fictious quantity used in link budget calculations to account for the fact that for a given quantity of receive antenna gain, the "capture area" or "effective aperture" of that receive antenna goes down with the square of frequency. IOW, a receive antenna that has 10dBi of gain at 10MHz will capture 100 times the energy (at 10 MHz) than a receive antenna that has 10dBi gain at 100 MHz will capture (at 100 MHz). This makes sense since a 10dBi antenna at 10 MHz is generally a lot bigger than a 10dBi antenna at 100 MHz. If free-space link budgets used effective aperture for the specifying the receive antenna gain instead of gain in dBi, then there would be no-need for a frequency dependent free-space path loss term. For non-free space links, however, there may in fact be a frequency dependent path loss term needed in the link calculation. Unlike free-space path loss which is a misnomer since there is no such thing a free-space path-loss (well there is, but its always 0dB), the non-free space loss loss term actually refers the physical loss characteristics of the path. 73, Mike W4EF.................
Reply to a comment by : W4EF on 2007-02-25

W4LGH >>And I still say using a tuner in your shack hooked to un-balanced line (coax) is ABSURD! You are only fooling yourself and your radio. You are NOT making your antenna work any better!<< A long time ago (back when I was a real W4), I had tuning network at the feedpoint of my 160 meter Marconi. I didn't have servo's on the matching components, so when I wanted to QSY across a significant frequency range, I had to walk outside (sometimes in the rain) to adjust the matching network. Now that I am a fake W4 (/W6 in Southern California), I match my 160 meter inverted-L from the shack through about 30 feet of low-loss coax. This makes QSYing much easier (especially when it's raining). In my particular case, there is a very slight compromise (~0.2dB loss) associated with matching the antenna from the shack through the coax. The convenience, however, of matching from the shack far outways the miniscule performance hit. Perhaps in your view of things that makes me an "F#%king idiot", but in my view I'd like to think that I am just exercising good engineering judgement by making a sensible tradeoff (convenience vs. 0.2dB extra loss). And anyway, the "system", is in fact resonant, even if the antenna by itself is not. 73, Mike W4EF.........
Reply to a comment by : KD2BD on 2007-02-25

W8JI wrote: > Capture area must be a Ham term. Not true. It is an antenna engineering term that has been around for decades. See the references and the discussion in my post above. > All that aside, it is virtually meaningless for determining how good an antenna is for receiving. Not true. Effective capture area multiplied times received power density (in watts per square meter) yields the power delivered by a receiving antenna into a matched load. Ohm's Law will provide the terminal voltage knowing its impedance. This is a VERY important piece of information when designing a communications system. 73, de John, KD2BD
Reply to a comment by : W8JI on 2007-02-23

"Capture area" really has little to do with physical size of the antenna. It relates solidly only to frequency and gain. The somewhat questionable exception is in an aperture antenna like a horn or parabolic reflector antenna. Even in these special aperture based antennas the effective aperture differs significantly from actual aperture, ranging from 45% to 75% with 65% being considered a very good design. If I have two exactly identical antennas in every way except I make one from a more lossy material, the lossy antenna will have less "capture area". Effective aperture is nothing more than a way we can correct for the change in wavelength and gain of antennas. If I have two antennas 500 feet apart, they are twice as far apart in terms of the wavelength as frequency is doubled. Capture area must be a Ham term. All that aside, it is virtually meaningless for determining how good an antenna is for receiving. Once the system limits on external noise concerns about absolute power or effective aperture are pointless. The only thing that matters is the ratio of desired signal to undesired signal received, and that has nothing to do with effective aperture or gain. It is all about pattern shape, not pattern size.
Reply to a comment by : KY1V on 2007-02-23

>RE: Benchmarks Reply by KY1V on February 23, 2007 Mail this to a friend! Yeah, that's how I want to spend my weekends, picking through garbage for antenna wire... Good Grief! David ~ KY1V< ::I plan to spend my retirement dumpster diving, because I didn't get much of this earlier. :-) WB2WIK/6 ------------------------ Maybe you can find a hardly used CapcitiveReciprocityMicroHomeBrewCoaxialDynamic Antenna wire in one of those and talk to me in Jamaica! I think I can hear you on your dummy load! David ~ KY1V
Reply to a comment by : WB2WIK on 2007-02-23

>RE: Benchmarks Reply by KY1V on February 23, 2007 Mail this to a friend! Yeah, that's how I want to spend my weekends, picking through garbage for antenna wire... Good Grief! David ~ KY1V< ::I plan to spend my retirement dumpster diving, because I didn't get much of this earlier. :-) WB2WIK/6
Reply to a comment by : KY1V on 2007-02-23

Yeah, that's how I want to spend my weekends, picking through garbage for antenna wire... Good Grief! David ~ KY1V
Reply to a comment by : N0AH on 2007-02-23

I say plug in coax to radio. Then feed coax to antenna. Check for any potetial problems. Have fun...bench that-
KC8QFP2007-02-25
RE: Benchmarks
The TWO best investments would be the antenna and the receiver. Not the matchbox, microphone, and linear! A little known secret, IMO, the 2$ eletret condensor mic element (as from Rad Shaft) isn't much different than what you'll find in a Yaesu or Icom desk mic! And you'll sound like crap on sideband regardless of how good your mic is. My ears tell me more than numbers! If you want a really good mic, invest in an ElectroVoice RE-20 broadcast microphone, then do AM! But you better learn about phantom power condensor mics first! The few db gain you get from a linniker is lost elsewhere, dare I repeat myself. Too many alligators out there crunching numbers.
Reply to a comment by : KC8QFP on 2007-02-25

One thing that really gets me is how the number crunchers end up using traps, tuners, randumb wire antennaes, and such which pretty much makes their numbers moot! All that $$$ and talk to waste power! Well it keeps MFJ and AES happy, they are counting the numbers$$$ Get out your calculators (and slide rules for the OF's), do the math, talk it over with other walking calculators, then take your wallets to the candy store and pay lots of extra cold hard cash for traps, tuners, and fancy wire. Like I said, the 3 db gain (if that is for real) is lost in the traps, 200+ feet of wire, and most of all through the tuner. Enjoy your spec sheets! Don
Reply to a comment by : W4EF on 2007-02-25

"Free-space path-loss" is indeed a fictious quantity used in link budget calculations to account for the fact that for a given quantity of receive antenna gain, the "capture area" or "effective aperture" of that receive antenna goes down with the square of frequency. IOW, a receive antenna that has 10dBi of gain at 10MHz will capture 100 times the energy (at 10 MHz) than a receive antenna that has 10dBi gain at 100 MHz will capture (at 100 MHz). This makes sense since a 10dBi antenna at 10 MHz is generally a lot bigger than a 10dBi antenna at 100 MHz. If free-space link budgets used effective aperture for the specifying the receive antenna gain instead of gain in dBi, then there would be no-need for a frequency dependent free-space path loss term. For non-free space links, however, there may in fact be a frequency dependent path loss term needed in the link calculation. Unlike free-space path loss which is a misnomer since there is no such thing a free-space path-loss (well there is, but its always 0dB), the non-free space loss loss term actually refers the physical loss characteristics of the path. 73, Mike W4EF.................
Reply to a comment by : W4EF on 2007-02-25

W4LGH >>And I still say using a tuner in your shack hooked to un-balanced line (coax) is ABSURD! You are only fooling yourself and your radio. You are NOT making your antenna work any better!<< A long time ago (back when I was a real W4), I had tuning network at the feedpoint of my 160 meter Marconi. I didn't have servo's on the matching components, so when I wanted to QSY across a significant frequency range, I had to walk outside (sometimes in the rain) to adjust the matching network. Now that I am a fake W4 (/W6 in Southern California), I match my 160 meter inverted-L from the shack through about 30 feet of low-loss coax. This makes QSYing much easier (especially when it's raining). In my particular case, there is a very slight compromise (~0.2dB loss) associated with matching the antenna from the shack through the coax. The convenience, however, of matching from the shack far outways the miniscule performance hit. Perhaps in your view of things that makes me an "F#%king idiot", but in my view I'd like to think that I am just exercising good engineering judgement by making a sensible tradeoff (convenience vs. 0.2dB extra loss). And anyway, the "system", is in fact resonant, even if the antenna by itself is not. 73, Mike W4EF.........
Reply to a comment by : KD2BD on 2007-02-25

W8JI wrote: > Capture area must be a Ham term. Not true. It is an antenna engineering term that has been around for decades. See the references and the discussion in my post above. > All that aside, it is virtually meaningless for determining how good an antenna is for receiving. Not true. Effective capture area multiplied times received power density (in watts per square meter) yields the power delivered by a receiving antenna into a matched load. Ohm's Law will provide the terminal voltage knowing its impedance. This is a VERY important piece of information when designing a communications system. 73, de John, KD2BD
Reply to a comment by : W8JI on 2007-02-23

"Capture area" really has little to do with physical size of the antenna. It relates solidly only to frequency and gain. The somewhat questionable exception is in an aperture antenna like a horn or parabolic reflector antenna. Even in these special aperture based antennas the effective aperture differs significantly from actual aperture, ranging from 45% to 75% with 65% being considered a very good design. If I have two exactly identical antennas in every way except I make one from a more lossy material, the lossy antenna will have less "capture area". Effective aperture is nothing more than a way we can correct for the change in wavelength and gain of antennas. If I have two antennas 500 feet apart, they are twice as far apart in terms of the wavelength as frequency is doubled. Capture area must be a Ham term. All that aside, it is virtually meaningless for determining how good an antenna is for receiving. Once the system limits on external noise concerns about absolute power or effective aperture are pointless. The only thing that matters is the ratio of desired signal to undesired signal received, and that has nothing to do with effective aperture or gain. It is all about pattern shape, not pattern size.
Reply to a comment by : KY1V on 2007-02-23

>RE: Benchmarks Reply by KY1V on February 23, 2007 Mail this to a friend! Yeah, that's how I want to spend my weekends, picking through garbage for antenna wire... Good Grief! David ~ KY1V< ::I plan to spend my retirement dumpster diving, because I didn't get much of this earlier. :-) WB2WIK/6 ------------------------ Maybe you can find a hardly used CapcitiveReciprocityMicroHomeBrewCoaxialDynamic Antenna wire in one of those and talk to me in Jamaica! I think I can hear you on your dummy load! David ~ KY1V
Reply to a comment by : WB2WIK on 2007-02-23

>RE: Benchmarks Reply by KY1V on February 23, 2007 Mail this to a friend! Yeah, that's how I want to spend my weekends, picking through garbage for antenna wire... Good Grief! David ~ KY1V< ::I plan to spend my retirement dumpster diving, because I didn't get much of this earlier. :-) WB2WIK/6
Reply to a comment by : KY1V on 2007-02-23

Yeah, that's how I want to spend my weekends, picking through garbage for antenna wire... Good Grief! David ~ KY1V
Reply to a comment by : N0AH on 2007-02-23

I say plug in coax to radio. Then feed coax to antenna. Check for any potetial problems. Have fun...bench that-
N3OX2007-02-25
RE: Benchmarks
"In Amateur Radio, effective capture area is an unfamiliar concept. We tend to prefer to think in terms of gain and efficiency, instead. This simplification leaves a lot out of the picture, and makes understanding concepts such radiated field density, field strength, path loss, gain, operating frequency, and the signal level delivered to a distant location more difficult to understand and accept. "

I think it gets left out of antenna descriptions entirely at HF because you never/almost never have to worry about being at the RX noise floor because you're not gathering enough signal.

In weak signal VHF/UHF work it's more sensible to start thinking about capture area and antenna aperature but gain and effective aperture are inseperable, right?

We don't ever have to guarantee delivery of a specific, prescribed minimum power to the receiver input... we do want to know how well our antennas work with respect to a reference dipole, though, so we talk about the gain of the antenna.

Good post on the subject, though... it's not something that I've been thinking about when I'm building antennas... but at VHF/UHF there really is a marked effect of not gathering enough signal.

Thanks!
Reply to a comment by : W4EF on 2007-02-25

"Free-space path-loss" is indeed a fictious quantity used in link budget calculations to account for the fact that for a given quantity of receive antenna gain, the "capture area" or "effective aperture" of that receive antenna goes down with the square of frequency. IOW, a receive antenna that has 10dBi of gain at 10MHz will capture 100 times the energy (at 10 MHz) than a receive antenna that has 10dBi gain at 100 MHz will capture (at 100 MHz). This makes sense since a 10dBi antenna at 10 MHz is generally a lot bigger than a 10dBi antenna at 100 MHz. If free-space link budgets used effective aperture for the specifying the receive antenna gain instead of gain in dBi, then there would be no-need for a frequency dependent free-space path loss term. For non-free space links, however, there may in fact be a frequency dependent path loss term needed in the link calculation. Unlike free-space path loss which is a misnomer since there is no such thing a free-space path-loss (well there is, but its always 0dB), the non-free space loss loss term actually refers the physical loss characteristics of the path. 73, Mike W4EF.................
Reply to a comment by : W4EF on 2007-02-25

W4LGH >>And I still say using a tuner in your shack hooked to un-balanced line (coax) is ABSURD! You are only fooling yourself and your radio. You are NOT making your antenna work any better!<< A long time ago (back when I was a real W4), I had tuning network at the feedpoint of my 160 meter Marconi. I didn't have servo's on the matching components, so when I wanted to QSY across a significant frequency range, I had to walk outside (sometimes in the rain) to adjust the matching network. Now that I am a fake W4 (/W6 in Southern California), I match my 160 meter inverted-L from the shack through about 30 feet of low-loss coax. This makes QSYing much easier (especially when it's raining). In my particular case, there is a very slight compromise (~0.2dB loss) associated with matching the antenna from the shack through the coax. The convenience, however, of matching from the shack far outways the miniscule performance hit. Perhaps in your view of things that makes me an "F#%king idiot", but in my view I'd like to think that I am just exercising good engineering judgement by making a sensible tradeoff (convenience vs. 0.2dB extra loss). And anyway, the "system", is in fact resonant, even if the antenna by itself is not. 73, Mike W4EF.........
Reply to a comment by : KD2BD on 2007-02-25

W8JI wrote: > Capture area must be a Ham term. Not true. It is an antenna engineering term that has been around for decades. See the references and the discussion in my post above. > All that aside, it is virtually meaningless for determining how good an antenna is for receiving. Not true. Effective capture area multiplied times received power density (in watts per square meter) yields the power delivered by a receiving antenna into a matched load. Ohm's Law will provide the terminal voltage knowing its impedance. This is a VERY important piece of information when designing a communications system. 73, de John, KD2BD
Reply to a comment by : W8JI on 2007-02-23

"Capture area" really has little to do with physical size of the antenna. It relates solidly only to frequency and gain. The somewhat questionable exception is in an aperture antenna like a horn or parabolic reflector antenna. Even in these special aperture based antennas the effective aperture differs significantly from actual aperture, ranging from 45% to 75% with 65% being considered a very good design. If I have two exactly identical antennas in every way except I make one from a more lossy material, the lossy antenna will have less "capture area". Effective aperture is nothing more than a way we can correct for the change in wavelength and gain of antennas. If I have two antennas 500 feet apart, they are twice as far apart in terms of the wavelength as frequency is doubled. Capture area must be a Ham term. All that aside, it is virtually meaningless for determining how good an antenna is for receiving. Once the system limits on external noise concerns about absolute power or effective aperture are pointless. The only thing that matters is the ratio of desired signal to undesired signal received, and that has nothing to do with effective aperture or gain. It is all about pattern shape, not pattern size.
Reply to a comment by : KY1V on 2007-02-23

>RE: Benchmarks Reply by KY1V on February 23, 2007 Mail this to a friend! Yeah, that's how I want to spend my weekends, picking through garbage for antenna wire... Good Grief! David ~ KY1V< ::I plan to spend my retirement dumpster diving, because I didn't get much of this earlier. :-) WB2WIK/6 ------------------------ Maybe you can find a hardly used CapcitiveReciprocityMicroHomeBrewCoaxialDynamic Antenna wire in one of those and talk to me in Jamaica! I think I can hear you on your dummy load! David ~ KY1V
Reply to a comment by : WB2WIK on 2007-02-23

>RE: Benchmarks Reply by KY1V on February 23, 2007 Mail this to a friend! Yeah, that's how I want to spend my weekends, picking through garbage for antenna wire... Good Grief! David ~ KY1V< ::I plan to spend my retirement dumpster diving, because I didn't get much of this earlier. :-) WB2WIK/6
Reply to a comment by : KY1V on 2007-02-23

Yeah, that's how I want to spend my weekends, picking through garbage for antenna wire... Good Grief! David ~ KY1V
Reply to a comment by : N0AH on 2007-02-23

I say plug in coax to radio. Then feed coax to antenna. Check for any potetial problems. Have fun...bench that-
KC8QFP2007-02-25
RE: Benchmarks
One thing that really gets me is how the number crunchers end up using traps, tuners, randumb wire antennaes, and such which pretty much makes their numbers moot! All that $$$ and talk to waste power! Well it keeps MFJ and AES happy, they are counting the numbers$$$ Get out your calculators (and slide rules for the OF's), do the math, talk it over with other walking calculators, then take your wallets to the candy store and pay lots of extra cold hard cash for traps, tuners, and fancy wire. Like I said, the 3 db gain (if that is for real) is lost in the traps, 200+ feet of wire, and most of all through the tuner. Enjoy your spec sheets! Don
Reply to a comment by : W4EF on 2007-02-25

"Free-space path-loss" is indeed a fictious quantity used in link budget calculations to account for the fact that for a given quantity of receive antenna gain, the "capture area" or "effective aperture" of that receive antenna goes down with the square of frequency. IOW, a receive antenna that has 10dBi of gain at 10MHz will capture 100 times the energy (at 10 MHz) than a receive antenna that has 10dBi gain at 100 MHz will capture (at 100 MHz). This makes sense since a 10dBi antenna at 10 MHz is generally a lot bigger than a 10dBi antenna at 100 MHz. If free-space link budgets used effective aperture for the specifying the receive antenna gain instead of gain in dBi, then there would be no-need for a frequency dependent free-space path loss term. For non-free space links, however, there may in fact be a frequency dependent path loss term needed in the link calculation. Unlike free-space path loss which is a misnomer since there is no such thing a free-space path-loss (well there is, but its always 0dB), the non-free space loss loss term actually refers the physical loss characteristics of the path. 73, Mike W4EF.................
Reply to a comment by : W4EF on 2007-02-25

W4LGH >>And I still say using a tuner in your shack hooked to un-balanced line (coax) is ABSURD! You are only fooling yourself and your radio. You are NOT making your antenna work any better!<< A long time ago (back when I was a real W4), I had tuning network at the feedpoint of my 160 meter Marconi. I didn't have servo's on the matching components, so when I wanted to QSY across a significant frequency range, I had to walk outside (sometimes in the rain) to adjust the matching network. Now that I am a fake W4 (/W6 in Southern California), I match my 160 meter inverted-L from the shack through about 30 feet of low-loss coax. This makes QSYing much easier (especially when it's raining). In my particular case, there is a very slight compromise (~0.2dB loss) associated with matching the antenna from the shack through the coax. The convenience, however, of matching from the shack far outways the miniscule performance hit. Perhaps in your view of things that makes me an "F#%king idiot", but in my view I'd like to think that I am just exercising good engineering judgement by making a sensible tradeoff (convenience vs. 0.2dB extra loss). And anyway, the "system", is in fact resonant, even if the antenna by itself is not. 73, Mike W4EF.........
Reply to a comment by : KD2BD on 2007-02-25

W8JI wrote: > Capture area must be a Ham term. Not true. It is an antenna engineering term that has been around for decades. See the references and the discussion in my post above. > All that aside, it is virtually meaningless for determining how good an antenna is for receiving. Not true. Effective capture area multiplied times received power density (in watts per square meter) yields the power delivered by a receiving antenna into a matched load. Ohm's Law will provide the terminal voltage knowing its impedance. This is a VERY important piece of information when designing a communications system. 73, de John, KD2BD
Reply to a comment by : W8JI on 2007-02-23

"Capture area" really has little to do with physical size of the antenna. It relates solidly only to frequency and gain. The somewhat questionable exception is in an aperture antenna like a horn or parabolic reflector antenna. Even in these special aperture based antennas the effective aperture differs significantly from actual aperture, ranging from 45% to 75% with 65% being considered a very good design. If I have two exactly identical antennas in every way except I make one from a more lossy material, the lossy antenna will have less "capture area". Effective aperture is nothing more than a way we can correct for the change in wavelength and gain of antennas. If I have two antennas 500 feet apart, they are twice as far apart in terms of the wavelength as frequency is doubled. Capture area must be a Ham term. All that aside, it is virtually meaningless for determining how good an antenna is for receiving. Once the system limits on external noise concerns about absolute power or effective aperture are pointless. The only thing that matters is the ratio of desired signal to undesired signal received, and that has nothing to do with effective aperture or gain. It is all about pattern shape, not pattern size.
Reply to a comment by : KY1V on 2007-02-23

>RE: Benchmarks Reply by KY1V on February 23, 2007 Mail this to a friend! Yeah, that's how I want to spend my weekends, picking through garbage for antenna wire... Good Grief! David ~ KY1V< ::I plan to spend my retirement dumpster diving, because I didn't get much of this earlier. :-) WB2WIK/6 ------------------------ Maybe you can find a hardly used CapcitiveReciprocityMicroHomeBrewCoaxialDynamic Antenna wire in one of those and talk to me in Jamaica! I think I can hear you on your dummy load! David ~ KY1V
Reply to a comment by : WB2WIK on 2007-02-23

>RE: Benchmarks Reply by KY1V on February 23, 2007 Mail this to a friend! Yeah, that's how I want to spend my weekends, picking through garbage for antenna wire... Good Grief! David ~ KY1V< ::I plan to spend my retirement dumpster diving, because I didn't get much of this earlier. :-) WB2WIK/6
Reply to a comment by : KY1V on 2007-02-23

Yeah, that's how I want to spend my weekends, picking through garbage for antenna wire... Good Grief! David ~ KY1V
Reply to a comment by : N0AH on 2007-02-23

I say plug in coax to radio. Then feed coax to antenna. Check for any potetial problems. Have fun...bench that-
W4EF2007-02-25
RE: Benchmarks
"Free-space path-loss" is indeed a fictious quantity used in link budget calculations to account for the fact that for a given quantity of receive antenna gain, the "capture area" or "effective aperture" of that receive antenna goes down with the square of frequency. IOW, a receive antenna that has 10dBi of gain at 10MHz will capture 100 times the energy (at 10 MHz) than a receive antenna that has 10dBi gain at 100 MHz will capture (at 100 MHz). This makes sense since a 10dBi antenna at 10 MHz is generally a lot bigger than a 10dBi antenna at 100 MHz. If free-space link budgets used effective aperture for the specifying the receive antenna gain instead of gain in dBi, then there would be no-need for a frequency dependent free-space path loss term. For non-free space links, however, there may in fact be a frequency dependent path loss term needed in the link calculation. Unlike free-space path loss which is a misnomer since there is no such thing a free-space path-loss (well there is, but its always 0dB), the non-free space loss loss term actually refers the physical loss characteristics of the path.

73, Mike W4EF.................
Reply to a comment by : W4EF on 2007-02-25

W4LGH >>And I still say using a tuner in your shack hooked to un-balanced line (coax) is ABSURD! You are only fooling yourself and your radio. You are NOT making your antenna work any better!<< A long time ago (back when I was a real W4), I had tuning network at the feedpoint of my 160 meter Marconi. I didn't have servo's on the matching components, so when I wanted to QSY across a significant frequency range, I had to walk outside (sometimes in the rain) to adjust the matching network. Now that I am a fake W4 (/W6 in Southern California), I match my 160 meter inverted-L from the shack through about 30 feet of low-loss coax. This makes QSYing much easier (especially when it's raining). In my particular case, there is a very slight compromise (~0.2dB loss) associated with matching the antenna from the shack through the coax. The convenience, however, of matching from the shack far outways the miniscule performance hit. Perhaps in your view of things that makes me an "F#%king idiot", but in my view I'd like to think that I am just exercising good engineering judgement by making a sensible tradeoff (convenience vs. 0.2dB extra loss). And anyway, the "system", is in fact resonant, even if the antenna by itself is not. 73, Mike W4EF.........
Reply to a comment by : KD2BD on 2007-02-25

W8JI wrote: > Capture area must be a Ham term. Not true. It is an antenna engineering term that has been around for decades. See the references and the discussion in my post above. > All that aside, it is virtually meaningless for determining how good an antenna is for receiving. Not true. Effective capture area multiplied times received power density (in watts per square meter) yields the power delivered by a receiving antenna into a matched load. Ohm's Law will provide the terminal voltage knowing its impedance. This is a VERY important piece of information when designing a communications system. 73, de John, KD2BD
Reply to a comment by : W8JI on 2007-02-23

"Capture area" really has little to do with physical size of the antenna. It relates solidly only to frequency and gain. The somewhat questionable exception is in an aperture antenna like a horn or parabolic reflector antenna. Even in these special aperture based antennas the effective aperture differs significantly from actual aperture, ranging from 45% to 75% with 65% being considered a very good design. If I have two exactly identical antennas in every way except I make one from a more lossy material, the lossy antenna will have less "capture area". Effective aperture is nothing more than a way we can correct for the change in wavelength and gain of antennas. If I have two antennas 500 feet apart, they are twice as far apart in terms of the wavelength as frequency is doubled. Capture area must be a Ham term. All that aside, it is virtually meaningless for determining how good an antenna is for receiving. Once the system limits on external noise concerns about absolute power or effective aperture are pointless. The only thing that matters is the ratio of desired signal to undesired signal received, and that has nothing to do with effective aperture or gain. It is all about pattern shape, not pattern size.
Reply to a comment by : KY1V on 2007-02-23

>RE: Benchmarks Reply by KY1V on February 23, 2007 Mail this to a friend! Yeah, that's how I want to spend my weekends, picking through garbage for antenna wire... Good Grief! David ~ KY1V< ::I plan to spend my retirement dumpster diving, because I didn't get much of this earlier. :-) WB2WIK/6 ------------------------ Maybe you can find a hardly used CapcitiveReciprocityMicroHomeBrewCoaxialDynamic Antenna wire in one of those and talk to me in Jamaica! I think I can hear you on your dummy load! David ~ KY1V
Reply to a comment by : WB2WIK on 2007-02-23

>RE: Benchmarks Reply by KY1V on February 23, 2007 Mail this to a friend! Yeah, that's how I want to spend my weekends, picking through garbage for antenna wire... Good Grief! David ~ KY1V< ::I plan to spend my retirement dumpster diving, because I didn't get much of this earlier. :-) WB2WIK/6
Reply to a comment by : KY1V on 2007-02-23

Yeah, that's how I want to spend my weekends, picking through garbage for antenna wire... Good Grief! David ~ KY1V
Reply to a comment by : N0AH on 2007-02-23

I say plug in coax to radio. Then feed coax to antenna. Check for any potetial problems. Have fun...bench that-
W4EF2007-02-25
RE: Benchmarks
W4LGH >>And I still say using a tuner in your shack hooked to un-balanced line (coax) is ABSURD! You are only fooling yourself and your radio. You are NOT making your antenna work any better!<<

A long time ago (back when I was a real W4), I had tuning network at the feedpoint of my 160 meter Marconi. I didn't have servo's on the matching components, so when I wanted to QSY across a significant frequency range, I had to walk outside (sometimes in the rain) to adjust the matching network.

Now that I am a fake W4 (/W6 in Southern California), I match my 160 meter inverted-L from the shack through about 30 feet of low-loss coax. This makes QSYing much easier (especially when it's raining). In my particular case, there is a very slight compromise (~0.2dB loss) associated with matching the antenna from the shack through the coax. The convenience, however, of matching from the shack far outways the miniscule performance hit.

Perhaps in your view of things that makes me an "F#%king idiot", but in my view I'd like to think that I am just exercising good engineering judgement by making a sensible tradeoff (convenience vs. 0.2dB extra loss). And anyway, the "system", is in fact resonant, even if the antenna by itself is not.

73, Mike W4EF.........

Reply to a comment by : KD2BD on 2007-02-25

W8JI wrote: > Capture area must be a Ham term. Not true. It is an antenna engineering term that has been around for decades. See the references and the discussion in my post above. > All that aside, it is virtually meaningless for determining how good an antenna is for receiving. Not true. Effective capture area multiplied times received power density (in watts per square meter) yields the power delivered by a receiving antenna into a matched load. Ohm's Law will provide the terminal voltage knowing its impedance. This is a VERY important piece of information when designing a communications system. 73, de John, KD2BD
Reply to a comment by : W8JI on 2007-02-23

"Capture area" really has little to do with physical size of the antenna. It relates solidly only to frequency and gain. The somewhat questionable exception is in an aperture antenna like a horn or parabolic reflector antenna. Even in these special aperture based antennas the effective aperture differs significantly from actual aperture, ranging from 45% to 75% with 65% being considered a very good design. If I have two exactly identical antennas in every way except I make one from a more lossy material, the lossy antenna will have less "capture area". Effective aperture is nothing more than a way we can correct for the change in wavelength and gain of antennas. If I have two antennas 500 feet apart, they are twice as far apart in terms of the wavelength as frequency is doubled. Capture area must be a Ham term. All that aside, it is virtually meaningless for determining how good an antenna is for receiving. Once the system limits on external noise concerns about absolute power or effective aperture are pointless. The only thing that matters is the ratio of desired signal to undesired signal received, and that has nothing to do with effective aperture or gain. It is all about pattern shape, not pattern size.
Reply to a comment by : KY1V on 2007-02-23

>RE: Benchmarks Reply by KY1V on February 23, 2007 Mail this to a friend! Yeah, that's how I want to spend my weekends, picking through garbage for antenna wire... Good Grief! David ~ KY1V< ::I plan to spend my retirement dumpster diving, because I didn't get much of this earlier. :-) WB2WIK/6 ------------------------ Maybe you can find a hardly used CapcitiveReciprocityMicroHomeBrewCoaxialDynamic Antenna wire in one of those and talk to me in Jamaica! I think I can hear you on your dummy load! David ~ KY1V
Reply to a comment by : WB2WIK on 2007-02-23

>RE: Benchmarks Reply by KY1V on February 23, 2007 Mail this to a friend! Yeah, that's how I want to spend my weekends, picking through garbage for antenna wire... Good Grief! David ~ KY1V< ::I plan to spend my retirement dumpster diving, because I didn't get much of this earlier. :-) WB2WIK/6
Reply to a comment by : KY1V on 2007-02-23

Yeah, that's how I want to spend my weekends, picking through garbage for antenna wire... Good Grief! David ~ KY1V
Reply to a comment by : N0AH on 2007-02-23

I say plug in coax to radio. Then feed coax to antenna. Check for any potetial problems. Have fun...bench that-
KC8QFP2007-02-25
RE: Benchmarks
I have to say that I'm with Alan on this topic too. One thing about being a ham, we are free to do as we please (within FCC limitations), in that we do not have to listen to the ""experts"". I am on a quest to do without the matchbox. I basically plan to use a remote switchobx so that multiple antennaes can be fed back to my shack via one feedline - to one multi-band rig. I really do not like multiband antennaes, especially with traps. I do not like randumb wires either. If one feels he must use a tuner, I think it is SBC that has a little relay filled box aka an auto-tuner. But that is supposed to be for randumb wire, not a matched antenna. Lots of $$$ to waste power! For me, KISS is the way to go with the antenna tuned for each band, or even section of a band. Verticals on 75/80, or even 40 is a pain in the ass. I think verticals are for the above thirty MHz crowd. Common sense, horizontal is much easier on HF. The few db that some gain from a three el tri-band beam, they lose in their traps and tuner at the other end! Better off with a half-square, and FAR CHEAPER TOO! Lot's of $$$ to waste watts, you can have your traps and tuners! Specs - huh!

Cheerz, Don
Reply to a comment by : W4LGH on 2007-02-25

And I still say using a tuner in your shack hooked to un-balanced line (coax) is ABSURD! You are only fooling yourself and your radio. You are NOT making your antenna work any better! Put the tuner/matching network @ the antenna, then you are doing something. Feed a dippole with open lead (balanced line) into your shack to a tuner, then you are tuning the feed line into the antenna, and that works somewhat. Install a resonant antenna system fed with low loss coax and now you really have something nice, and its done the right way. I have said that from the begining, and I stand by what I say. I have not changed my opinion, nor have I put any spin on words. I still say if Stan truely believes that the manufactures build in antenna tuners into the new rigs, and that how he justifies that antenna tuners hooked to un-balanced line are good and work, I still say you sir are an IDIOT, and I still think you should buy the ocean front properity in Azronia, while its still a bargin! Stan you can spin it anyway you want, say whatever you want, its a free country. I know what I have said, and I know what everyone else on here has said, including you sir. I am done with this silly ass you said, he said, they said, BS. I will send you some cheese to go with your wine, but you can have it all to yourself. Say you won if you want, call it whatever, but I am not longer going to play your silly game. My junk works, I have no tuners on ANY lines, my antenna systems are resonant. You do what you want! 73 de W4LGH - ALan http://www.w4lgh.com
Reply to a comment by : KC8QFP on 2007-02-25

IMO, Tuners are something that I'd rather do without. I'd like to do away with all the damn wire and the infamous matchbox for good! I don't understand why hams seem to like the darn things, maybe its the two big knobs to play with or something? I was thinking about setting up a shack like in a treehouse so I would not need the coax and matchbox. Then I could connect the antenna directly to my rig. Just call me Tarzan! Hi Hi! I don't know if it is Murphy's Law or what, but wire seems to always get all tangled up in a mess. It's worse than a garden hose! Just drop a wire on the floor, and it's a tangled mess of knots! All the wires on my confuser, my hifi system, TV/VCR, ham radio junk, PA system (for music), and the XMAS lights (don't forget the XMAS lights)! If it were to be a choice between a matched antenna or a matchbox, I go with the proper antenna hands down! As for benchmark numbers and specs vs actual performance, that is sort of like when you put up your antenna, avoid perfect weather, it doesn't work right, you have to put your antenna up when the weather is bad for it to work right! Cheerz! Don
Reply to a comment by : K9IUQ on 2007-02-25

W4GLH continues with his ranting: You made the statemant if tuners weren't any good, why did they put them in radios? K9IUQ says without vulgarity: Don't try to spin what I say, like you do with your comments. You want to quote what I say in past posts, fine. Since you don't seem to know how to use the find key in a Browser, here is what was said word for word NO SPIN and DIRECT QUOTES: .................. You W4LGH said: The idea of an antenna tuner hooked to an un-balanced line (coax) is absurd And K9IUQ replied : If this was true we wouldn't have built-in antenna tuners in our rigs. Stan K9IUQ
Reply to a comment by : W4LGH on 2007-02-25

Stan K9IUQ wrote.. But remember W4LGH said The idea of an antenna tuner hooked to an un-balanced line (coax) is absurd. And w4LGH said the reason they put antenna tuners in radios is so F#$KING IDIOTS like you will BUY THEM!! Statements like that I have a REAL problem with. ================ Why is that Stan, did you just learn you are a F#^KING IDIOT? Would you like some cheese to go with that wine? W4LGH said this and W4LGH said that... Jesus H Crist Stan...GROW UP! You made the statemant if tuners weren't any good, why did they put them in radios? If that statement is the basis of your logic, I rest my case! Damn I hate it when someone pushes me into calling them names, but I guess if the shoe fits...
Reply to a comment by : KC8QFP on 2007-02-25

There was a discussion on the ""Where will Ham Radio be 50 Years from Now"" about remote control wireless link between the shack and tower, i.e. no more need for feedline! You'd have a control head or PC remote that might use IR, low powered RF, or LASER to send signals to the tower for xceiver remote control, rotor, and perhaps even linear. So the tower would onlyneed a power source (120/220VAC 10g line). They do this with X-10 cameras, I was thinking about mounting one of those up on my tower. A simple way to direct couple the transmitter to the antenna! WOW! I sure would like to see TenTec or Drake make such a rig! YaeComWood already has full spectrum HT's, and TenTec has a PC controlled xceiver, with a few mods, this would be a great RC rig (if it has a USB port). I sure would like to see Drake get back into ham radio with such a rig! 73, Don
Reply to a comment by : K9IUQ on 2007-02-25

N3OX says It's also a *fact* that feeding a 20m dipole on 40m (14-j1000) through 30 feet of RG-8/X coax leads to 16dB feedline loss. Both of these cases (good coax, 5:1 SWR and common, cheap coax, 670:1 SWR) are encountered in amateur radio every day. The first one by people who are sensibly trying to stretch the frequency coverage of their 75m/80m dipole without complicated tricks at the antenna, and the latter by people who find that they can "find a match" on 40m with their 20m dipole and they can hear stations. In the former case, it's fine to use the tuner on your coax fed antenna. In the latter, it's absurd. ......................................................... I agree with you 100 percent, there is a time and place for an antenna tuner on coax. But remember W4LGH said The idea of an antenna tuner hooked to an un-balanced line (coax) is absurd. And w4LGH said the reason they put antenna tuners in radios is so F#$KING IDIOTS like you will BUY THEM!! Statements like that I have a REAL problem with. Stan K9IUQ
KD2BD2007-02-25
RE: Benchmarks
W8JI wrote:

> Capture area must be a Ham term.

Not true. It is an antenna engineering term that has been around for decades. See the references and the discussion in my post above.

> All that aside, it is virtually meaningless for determining how good an antenna is for receiving.

Not true. Effective capture area multiplied times received power density (in watts per square meter) yields the power delivered by a receiving antenna into a matched load. Ohm's Law will provide the terminal voltage knowing its impedance.

This is a VERY important piece of information when designing a communications system.


73, de John, KD2BD
Reply to a comment by : W8JI on 2007-02-23

"Capture area" really has little to do with physical size of the antenna. It relates solidly only to frequency and gain. The somewhat questionable exception is in an aperture antenna like a horn or parabolic reflector antenna. Even in these special aperture based antennas the effective aperture differs significantly from actual aperture, ranging from 45% to 75% with 65% being considered a very good design. If I have two exactly identical antennas in every way except I make one from a more lossy material, the lossy antenna will have less "capture area". Effective aperture is nothing more than a way we can correct for the change in wavelength and gain of antennas. If I have two antennas 500 feet apart, they are twice as far apart in terms of the wavelength as frequency is doubled. Capture area must be a Ham term. All that aside, it is virtually meaningless for determining how good an antenna is for receiving. Once the system limits on external noise concerns about absolute power or effective aperture are pointless. The only thing that matters is the ratio of desired signal to undesired signal received, and that has nothing to do with effective aperture or gain. It is all about pattern shape, not pattern size.
Reply to a comment by : KY1V on 2007-02-23

>RE: Benchmarks Reply by KY1V on February 23, 2007 Mail this to a friend! Yeah, that's how I want to spend my weekends, picking through garbage for antenna wire... Good Grief! David ~ KY1V< ::I plan to spend my retirement dumpster diving, because I didn't get much of this earlier. :-) WB2WIK/6 ------------------------ Maybe you can find a hardly used CapcitiveReciprocityMicroHomeBrewCoaxialDynamic Antenna wire in one of those and talk to me in Jamaica! I think I can hear you on your dummy load! David ~ KY1V
Reply to a comment by : WB2WIK on 2007-02-23

>RE: Benchmarks Reply by KY1V on February 23, 2007 Mail this to a friend! Yeah, that's how I want to spend my weekends, picking through garbage for antenna wire... Good Grief! David ~ KY1V< ::I plan to spend my retirement dumpster diving, because I didn't get much of this earlier. :-) WB2WIK/6
Reply to a comment by : KY1V on 2007-02-23

Yeah, that's how I want to spend my weekends, picking through garbage for antenna wire... Good Grief! David ~ KY1V
Reply to a comment by : N0AH on 2007-02-23

I say plug in coax to radio. Then feed coax to antenna. Check for any potetial problems. Have fun...bench that-
W4LGH2007-02-25
RE: Benchmarks
And I still say using a tuner in your shack hooked to un-balanced line (coax) is ABSURD! You are only fooling yourself and your radio. You are NOT making your antenna work any better! Put the tuner/matching network @ the antenna, then you are doing something. Feed a dippole with open lead (balanced line) into your shack to a tuner, then you are tuning the feed line into the antenna, and that works somewhat.

Install a resonant antenna system fed with low loss coax and now you really have something nice, and its done the right way. I have said that from the begining, and I stand by what I say. I have not changed my opinion, nor have I put any spin on words.

I still say if Stan truely believes that the manufactures build in antenna tuners into the new rigs, and that how he justifies that antenna tuners hooked to un-balanced line are good and work, I still
say you sir are an IDIOT, and I still think you should buy the ocean front properity in Azronia, while its still a bargin! Stan you can spin it anyway you want, say whatever you want, its a free country. I know what I have said, and I know what everyone else on here has said, including you sir. I am done with this silly ass you said, he said, they said, BS.
I will send you some cheese to go with your wine, but you can have it all to yourself. Say you won if you want, call it whatever, but I am not longer going to play your silly game.


My junk works, I have no tuners on ANY lines, my antenna systems are resonant. You do what you want!

73 de W4LGH - ALan
http://www.w4lgh.com
Reply to a comment by : KC8QFP on 2007-02-25

IMO, Tuners are something that I'd rather do without. I'd like to do away with all the damn wire and the infamous matchbox for good! I don't understand why hams seem to like the darn things, maybe its the two big knobs to play with or something? I was thinking about setting up a shack like in a treehouse so I would not need the coax and matchbox. Then I could connect the antenna directly to my rig. Just call me Tarzan! Hi Hi! I don't know if it is Murphy's Law or what, but wire seems to always get all tangled up in a mess. It's worse than a garden hose! Just drop a wire on the floor, and it's a tangled mess of knots! All the wires on my confuser, my hifi system, TV/VCR, ham radio junk, PA system (for music), and the XMAS lights (don't forget the XMAS lights)! If it were to be a choice between a matched antenna or a matchbox, I go with the proper antenna hands down! As for benchmark numbers and specs vs actual performance, that is sort of like when you put up your antenna, avoid perfect weather, it doesn't work right, you have to put your antenna up when the weather is bad for it to work right! Cheerz! Don
Reply to a comment by : K9IUQ on 2007-02-25

W4GLH continues with his ranting: You made the statemant if tuners weren't any good, why did they put them in radios? K9IUQ says without vulgarity: Don't try to spin what I say, like you do with your comments. You want to quote what I say in past posts, fine. Since you don't seem to know how to use the find key in a Browser, here is what was said word for word NO SPIN and DIRECT QUOTES: .................. You W4LGH said: The idea of an antenna tuner hooked to an un-balanced line (coax) is absurd And K9IUQ replied : If this was true we wouldn't have built-in antenna tuners in our rigs. Stan K9IUQ
Reply to a comment by : W4LGH on 2007-02-25

Stan K9IUQ wrote.. But remember W4LGH said The idea of an antenna tuner hooked to an un-balanced line (coax) is absurd. And w4LGH said the reason they put antenna tuners in radios is so F#$KING IDIOTS like you will BUY THEM!! Statements like that I have a REAL problem with. ================ Why is that Stan, did you just learn you are a F#^KING IDIOT? Would you like some cheese to go with that wine? W4LGH said this and W4LGH said that... Jesus H Crist Stan...GROW UP! You made the statemant if tuners weren't any good, why did they put them in radios? If that statement is the basis of your logic, I rest my case! Damn I hate it when someone pushes me into calling them names, but I guess if the shoe fits...
Reply to a comment by : KC8QFP on 2007-02-25

There was a discussion on the ""Where will Ham Radio be 50 Years from Now"" about remote control wireless link between the shack and tower, i.e. no more need for feedline! You'd have a control head or PC remote that might use IR, low powered RF, or LASER to send signals to the tower for xceiver remote control, rotor, and perhaps even linear. So the tower would onlyneed a power source (120/220VAC 10g line). They do this with X-10 cameras, I was thinking about mounting one of those up on my tower. A simple way to direct couple the transmitter to the antenna! WOW! I sure would like to see TenTec or Drake make such a rig! YaeComWood already has full spectrum HT's, and TenTec has a PC controlled xceiver, with a few mods, this would be a great RC rig (if it has a USB port). I sure would like to see Drake get back into ham radio with such a rig! 73, Don
Reply to a comment by : K9IUQ on 2007-02-25

N3OX says It's also a *fact* that feeding a 20m dipole on 40m (14-j1000) through 30 feet of RG-8/X coax leads to 16dB feedline loss. Both of these cases (good coax, 5:1 SWR and common, cheap coax, 670:1 SWR) are encountered in amateur radio every day. The first one by people who are sensibly trying to stretch the frequency coverage of their 75m/80m dipole without complicated tricks at the antenna, and the latter by people who find that they can "find a match" on 40m with their 20m dipole and they can hear stations. In the former case, it's fine to use the tuner on your coax fed antenna. In the latter, it's absurd. ......................................................... I agree with you 100 percent, there is a time and place for an antenna tuner on coax. But remember W4LGH said The idea of an antenna tuner hooked to an un-balanced line (coax) is absurd. And w4LGH said the reason they put antenna tuners in radios is so F#$KING IDIOTS like you will BUY THEM!! Statements like that I have a REAL problem with. Stan K9IUQ
W4EF2007-02-25
RE: Benchmarks
There are some very good simple-to-use analytical tools out there that can be used to determine the losses associated with using an antenna tuner on a mis-matched feedline:

1) Kevin Schmidt's antenna tuner java applet

http://fermi.la.asu.edu/w9cf/tuner/tuner.html

2) N6BV's TLW (Transmission Line for Windows) and

3) N6BV's AAT (Analyze Antenna Tuner)

Both (2) and (3) are included on the CD that comes with the ARRL Antenna Handbook.

Using these programs you can calculate how much additional loss is associated with matching an antenna in the shack with a tuner vs. doing the matching at the antenna feedpoint. In many cases using the tuner in the shack is a good tradeoff, in other cases (N3OX provides a good example) it's a huge performance hit. You really can't generalize about these things. You have to look at the application specifics.

73, Mike W4EF.....................
Reply to a comment by : KC8QFP on 2007-02-25

IMO, Tuners are something that I'd rather do without. I'd like to do away with all the damn wire and the infamous matchbox for good! I don't understand why hams seem to like the darn things, maybe its the two big knobs to play with or something? I was thinking about setting up a shack like in a treehouse so I would not need the coax and matchbox. Then I could connect the antenna directly to my rig. Just call me Tarzan! Hi Hi! I don't know if it is Murphy's Law or what, but wire seems to always get all tangled up in a mess. It's worse than a garden hose! Just drop a wire on the floor, and it's a tangled mess of knots! All the wires on my confuser, my hifi system, TV/VCR, ham radio junk, PA system (for music), and the XMAS lights (don't forget the XMAS lights)! If it were to be a choice between a matched antenna or a matchbox, I go with the proper antenna hands down! As for benchmark numbers and specs vs actual performance, that is sort of like when you put up your antenna, avoid perfect weather, it doesn't work right, you have to put your antenna up when the weather is bad for it to work right! Cheerz! Don
Reply to a comment by : K9IUQ on 2007-02-25

W4GLH continues with his ranting: You made the statemant if tuners weren't any good, why did they put them in radios? K9IUQ says without vulgarity: Don't try to spin what I say, like you do with your comments. You want to quote what I say in past posts, fine. Since you don't seem to know how to use the find key in a Browser, here is what was said word for word NO SPIN and DIRECT QUOTES: .................. You W4LGH said: The idea of an antenna tuner hooked to an un-balanced line (coax) is absurd And K9IUQ replied : If this was true we wouldn't have built-in antenna tuners in our rigs. Stan K9IUQ
Reply to a comment by : W4LGH on 2007-02-25

Stan K9IUQ wrote.. But remember W4LGH said The idea of an antenna tuner hooked to an un-balanced line (coax) is absurd. And w4LGH said the reason they put antenna tuners in radios is so F#$KING IDIOTS like you will BUY THEM!! Statements like that I have a REAL problem with. ================ Why is that Stan, did you just learn you are a F#^KING IDIOT? Would you like some cheese to go with that wine? W4LGH said this and W4LGH said that... Jesus H Crist Stan...GROW UP! You made the statemant if tuners weren't any good, why did they put them in radios? If that statement is the basis of your logic, I rest my case! Damn I hate it when someone pushes me into calling them names, but I guess if the shoe fits...
Reply to a comment by : KC8QFP on 2007-02-25

There was a discussion on the ""Where will Ham Radio be 50 Years from Now"" about remote control wireless link between the shack and tower, i.e. no more need for feedline! You'd have a control head or PC remote that might use IR, low powered RF, or LASER to send signals to the tower for xceiver remote control, rotor, and perhaps even linear. So the tower would onlyneed a power source (120/220VAC 10g line). They do this with X-10 cameras, I was thinking about mounting one of those up on my tower. A simple way to direct couple the transmitter to the antenna! WOW! I sure would like to see TenTec or Drake make such a rig! YaeComWood already has full spectrum HT's, and TenTec has a PC controlled xceiver, with a few mods, this would be a great RC rig (if it has a USB port). I sure would like to see Drake get back into ham radio with such a rig! 73, Don
Reply to a comment by : K9IUQ on 2007-02-25

N3OX says It's also a *fact* that feeding a 20m dipole on 40m (14-j1000) through 30 feet of RG-8/X coax leads to 16dB feedline loss. Both of these cases (good coax, 5:1 SWR and common, cheap coax, 670:1 SWR) are encountered in amateur radio every day. The first one by people who are sensibly trying to stretch the frequency coverage of their 75m/80m dipole without complicated tricks at the antenna, and the latter by people who find that they can "find a match" on 40m with their 20m dipole and they can hear stations. In the former case, it's fine to use the tuner on your coax fed antenna. In the latter, it's absurd. ......................................................... I agree with you 100 percent, there is a time and place for an antenna tuner on coax. But remember W4LGH said The idea of an antenna tuner hooked to an un-balanced line (coax) is absurd. And w4LGH said the reason they put antenna tuners in radios is so F#$KING IDIOTS like you will BUY THEM!! Statements like that I have a REAL problem with. Stan K9IUQ
KD2BD2007-02-25
RE: Benchmarks
WB2WIK/6 on February 23, 2007 wrote in reply to my earlier posting:

> I think what this calculation demonstrates is the reduction in a
> resonant antenna's effective capture area as frequency is raised.
> This is a property that most certainly obeys the theory of reciprocity.

::That's not true. Where'd you find this information?

It most certainly IS true, Steve.

Refer to the ITT "Reference Data For Radio Engineers", and/or "Antennas" by Kraus, and/or "The Antenna Engineering Handbook" by Jasik/Johnson and Equations 2 and 3 in this posting for verification.

> Antenna gain is directly related to effective capture area (and
> frequency). It is impossible for an antenna to have different gain
> on RX than it does on TX.

::That can be true if there is no transmission line, at all. As soon as you add a transmission line, this statement doesn't hold. Tom W8JI (posting above) explained why.

I'm not sure that's a significant enough of an effect to warrant serious consideration, but for the sake of discussion, let's say the system is well designed and properly matched on both ends.

> An antenna's effective capture area is most often a term that is absorbed
> into free space path loss calculations.

::It is? Where? Free space path loss is very well understood and calculable and isn't related to antennas used.

It is more than a simple coincidence that "free space path loss" varies in direct proportion to the change in an antenna's effective capture area with changing frequency while gain is held constant.

You are no doubt aware that there is a nearly 10 dB increase in "free space path loss" as we go from 144 MHz to 432 MHz:

Loss = 32.4 20 log (f) 20 log (d) (Equation 1)

...where "Loss" is in decibels, "f" is the frequency in MHz, and "d" is the free space path distance in kilometers (ARRL, "Satellite Experimenter's Handbook").

But the rise in path loss with increasing frequency is not an effect of free space, nor is it an effect of scattering or absorption at these frequencies.

So, where does the increase in line-of-sight path loss come from when we move to higher frequencies?

It comes from the fact that (for example) a 100% efficient, resonant, properly matched dipole exhibiting 0 dBd gain at 432 MHz has only about one tenth the effective capture area of an equivalent 0 dBd gain dipole at 144 MHz. It takes nearly a 10 dBd gain antenna at 432 MHz to exhibit the same effective capture area (and therefore deliver the same field
strength) as a dipole at 2-meters across the same distance of free space.

> It is well understood that as frequency is increased, the free
> space path loss also increases. In reality, free space is lossless.

::In a vacuum (no atmosphere, no ionosphere), this is close. But we don't work in free space.

I am well aware of that. :-) In fact, I've authored software that estimates 20 MHz to 20 GHz path loss over the Earth's surface using 3 arc-second digital terrain model data and the Longley-Rice Irregular Terrain Model (see: http://www.qsl.net/kd2bd/splat.html).

However, we cannot begin to understand what happens in the "real world" until we first understand some very basic properties of antennas, gain, "path loss", and capture area, and there seems to be some real misconceptions in these areas as evidenced by some of the remarks generated through this discussion.

With regard to free space, I earlier stated:

> It doesn't care about frequency. Signals traveling across free space
> get weaker as frequency is raised due to the reduction in effective capture
> areas of the antennas on each end of the RF circuit.

::What?

Feed one watt of RF into a resonant dipole at 144 MHz in free space. Place a a second dipole 5 miles away broadside to the first and measure the voltage induced into it from the 1-watt transmitter.

Repeat the experiment with resonant dipoles at some higher frequency.

The induced voltage will be measurably less, despite the fact the TX power is the same, the distance between the antennas is the same, the gain of the antennas is the same, their beamwidths are the same, their impedances are the same, and the "loss" across free space is the same.

> A parabolic dish is an exception to the rule. A parabolic dish maintains
> a constant effective capture area regardless of frequency. Dipoles, yagis,
> etc. do not.

::What?

And I would add panel antennas (broadside arrays), horn antennas, and corner reflectors as being very similar in behavior to parabolics across their (understandably narrower) design range.

Now, repeat the above experiment with parabolic dish antennas instead of dipoles. The induced voltage will very nearly be the same, despite the change in antenna gain and antenna beamwidth that occurred with the change in operating frequency.

Why the difference?

The effective capture area (in square feet) of a parabolic dish doesn't change as the operating frequency is changed. It is a fixed physical quantity (assuming a constant feed horn efficiency). Yet, we would expect it to have significantly higher gain (and consequently a sharper pattern) on 10 GHz than it would have on 2-meters without having to think twice about it. We would also expect a 10 dBd gain yagi on 20-meters to be much larger than a 10 dBd gain antenna on 432 MHz even though they both exhibit the same amount of gain and beamwidth.

How can the gain of a dish antenna increase with increasing frequency when its physical size remains exactly the same? Where does that increasing "gain" come from?

How can two 10 dB gain antennas have drastically different physical dimensions, yet similar beamwidths?

How can stacking yagis yield increasing gain when we're equally dividing the power split amongst all antennas in the array in the first place?

Is there an optimum stacking distance between yagis in the array, and is that distance dependent upon frequency and the gain of the individual yagis?

The answers to these questions can be found through an understanding of the following concept:

::Question: How do you calculate capture area? Let's see the formula you use.

Effective capture area = (Gain x Lambda Squared) / Four Pi (Equation 2)

Gain = (Four Pi x Effective Capture Area) / Lambda Squared (Equation 3)

...where Gain is expressed as a real number (not dB) referenced to an isotropic source, and Lambda is the wavelength in free space. Effective capture area is expressed in the same units as Lambda.

Notice there's no distinction whether the antenna is transmitting or receiving. As I started earlier, it is irrelevant. An antenna's capture area doesn't magically shrink or grow in size depending on whether it's transmitting or receiving. It obeys the law of reciprocity.

Plugging in some numbers, we find a dipole at 432 MHz has an effective capture area of approximately 0.0628 square meters, whereas a dipole at 144 MHz has an effective capture area of approximately 0.565 square meters. It takes nearly 10 dB more gain at 432 MHz to equal the effective capture area (and equal the radiated field strength) of antenna at 144 MHz.

This, incidentally, correlates exactly with the "path loss" predicted through Equation 1. The proof is left as an exercise for the student. :-)

A 22 dBd EME array on 2-meters has an effective capture area of around 89.6 square meters, while a simple dipole on 75-meters has an effective capture area of 732.7 square meters! No wonder those 75-meter signals are so strong!

In fact, a 75-meter dipole has the same capture area (signal gathering ability) as a 31 dBd gain antenna on 2-meters and a 40 dBd gain antenna on 70-cm.

75-meter QRP EME, anyone? :-) (Don't laugh. If not for the noise levels and the ionosphere, these figures suggest it would certainly be possible.)

While there are other factors at play, the optimum stacking distance between yagis in an array is generally the distance at which the effective capture area of each yagi (converted to the shape of a circle) just overlaps the next, just as you might stack parabolic dishes or panel antennas in an array to create a contiguous "wall" of RF.

As the gain of the individual yagis increases, the optimum stacking distance also increases. If the frequency decreases while the gain of each yagi (number of elements/boom length) remains the same, the stacking distance increases as well -- all because the effective capture area of each yagi increases with increasing gain and decreasing frequency.

The reason we get nearly a four-fold (6 dB) increase in gain when we stack 4 yagis in an H-frame arrangement (despite the fact we're feeding only a quarter of our total power into each yagi through our power divider and dispersing it over a wider area) is because we are feeding our total power into an array that has 4 times the effective capture area as that of any individual yagi. It is the increased capture area of the array as a whole and the dispersion of that RF over the increased surface area of the array that is providing the boost in gain.

In Amateur Radio, effective capture area is an unfamiliar concept. We tend to prefer to think in terms of gain and efficiency, instead. This simplification leaves a lot out of the picture, and makes understanding concepts such radiated field density, field strength, path loss, gain, operating frequency, and the signal level delivered to a distant location more difficult to understand and accept.


73, de John, KD2BD
Reply to a comment by : K9IUQ on 2007-02-25

KU2US says So put em' up, use them and be happy.. ........................................................ Truer words were never said about antennas. You could put up a text- book antenna and it might work better (or worse) than predicted because of things you cant control - like the surrounding environment. This whole thread has shown me that hams take antennas way to seriously. Do the best you can making and putting up antenna and dont worry if you cant get it textbook perfect. let me tell you a little story, that the oldtimers here will smile about.. Back around 1960 a young lad of 14 got a novice license. He didnt have much money, a paper route didnt pay much back then. He scraped up enough money to buy an Eico 720 kit and put it together. He didnt have any money for a Receiver, but after much begging his mother bought a Hammarlund HQ 100 on time payments - provided he paid for it out of his paper route money. This young lad was friends with the local TV Repairman who had a shop in town. EVERY day after school the lad would stop and talk to his tv repairman friend. The TV guy gave the lad parts, just all kind of good things. The Lad talked TV Guy into giving him some used 300 ohm tv line. this was the reall cheap stuff that no one would buy today. The lad also got some used wired and a knife switch from the tv guy. Now the Lad had everything for a station. He read all the antenna info he could and decided to put up a 130 wired fed in the center with the 300 ohm used elcheapo tv twinlead. He hooked the tv line up the the knife switch. This was so the Lad could go from rx to tx. The Eico 720 had a coax input, what to do. The lad couldnt afford coax, it was way exp$pen$ive back in 1960. So he talked his TV repairmen into getting him a pl259 cheep. The lad soldered the pl259 onto the tv line and screwed into the xmtr. Didnt have no internal antenna tuner, no the EICO just had a pi-network. Now if this lad would of had internet he would had 10 hams tell him that this just wasnt gonna work, no its against the laws of nature. But in 1960 internet was not around and the lad wasnt smart enough, (he was only 14 remember,) to know this antenna wasnt going to work. So the lad proceeded to work nearly 35 countries and made WAS with this antenna as a novice. Did I say that novices could only use crystals back then and the lad only had 2 crystals. Good thing that lad didnt have internet, he wouldnt tried and worked all that stuff called dx. I mean everyone knows you cant use cheap used 300ohm tv line on an antenna. This lad is smart now, he has learned never to believe much on the internet. He still does dumb things like use a Tuner with coax, make non-resonant antennas and feed them with 600 ohm feeders (he doesnt use tv line any more tho). Stan K9IUQ - ROTFL
KC8QFP2007-02-25
RE: Benchmarks
IMO, Tuners are something that I'd rather do without. I'd like to do away with all the damn wire and the infamous matchbox for good! I don't understand why hams seem to like the darn things, maybe its the two big knobs to play with or something? I was thinking about setting up a shack like in a treehouse so I would not need the coax and matchbox. Then I could connect the antenna directly to my rig. Just call me Tarzan! Hi Hi! I don't know if it is Murphy's Law or what, but wire seems to always get all tangled up in a mess. It's worse than a garden hose! Just drop a wire on the floor, and it's a tangled mess of knots! All the wires on my confuser, my hifi system, TV/VCR, ham radio junk, PA system (for music), and the XMAS lights (don't forget the XMAS lights)! If it were to be a choice between a matched antenna or a matchbox, I go with the proper antenna hands down! As for benchmark numbers and specs vs actual performance, that is sort of like when you put up your antenna, avoid perfect weather, it doesn't work right, you have to put your antenna up when the weather is bad for it to work right!

Cheerz! Don
Reply to a comment by : K9IUQ on 2007-02-25

W4GLH continues with his ranting: You made the statemant if tuners weren't any good, why did they put them in radios? K9IUQ says without vulgarity: Don't try to spin what I say, like you do with your comments. You want to quote what I say in past posts, fine. Since you don't seem to know how to use the find key in a Browser, here is what was said word for word NO SPIN and DIRECT QUOTES: .................. You W4LGH said: The idea of an antenna tuner hooked to an un-balanced line (coax) is absurd And K9IUQ replied : If this was true we wouldn't have built-in antenna tuners in our rigs. Stan K9IUQ
Reply to a comment by : W4LGH on 2007-02-25

Stan K9IUQ wrote.. But remember W4LGH said The idea of an antenna tuner hooked to an un-balanced line (coax) is absurd. And w4LGH said the reason they put antenna tuners in radios is so F#$KING IDIOTS like you will BUY THEM!! Statements like that I have a REAL problem with. ================ Why is that Stan, did you just learn you are a F#^KING IDIOT? Would you like some cheese to go with that wine? W4LGH said this and W4LGH said that... Jesus H Crist Stan...GROW UP! You made the statemant if tuners weren't any good, why did they put them in radios? If that statement is the basis of your logic, I rest my case! Damn I hate it when someone pushes me into calling them names, but I guess if the shoe fits...
Reply to a comment by : KC8QFP on 2007-02-25

There was a discussion on the ""Where will Ham Radio be 50 Years from Now"" about remote control wireless link between the shack and tower, i.e. no more need for feedline! You'd have a control head or PC remote that might use IR, low powered RF, or LASER to send signals to the tower for xceiver remote control, rotor, and perhaps even linear. So the tower would onlyneed a power source (120/220VAC 10g line). They do this with X-10 cameras, I was thinking about mounting one of those up on my tower. A simple way to direct couple the transmitter to the antenna! WOW! I sure would like to see TenTec or Drake make such a rig! YaeComWood already has full spectrum HT's, and TenTec has a PC controlled xceiver, with a few mods, this would be a great RC rig (if it has a USB port). I sure would like to see Drake get back into ham radio with such a rig! 73, Don
Reply to a comment by : K9IUQ on 2007-02-25

N3OX says It's also a *fact* that feeding a 20m dipole on 40m (14-j1000) through 30 feet of RG-8/X coax leads to 16dB feedline loss. Both of these cases (good coax, 5:1 SWR and common, cheap coax, 670:1 SWR) are encountered in amateur radio every day. The first one by people who are sensibly trying to stretch the frequency coverage of their 75m/80m dipole without complicated tricks at the antenna, and the latter by people who find that they can "find a match" on 40m with their 20m dipole and they can hear stations. In the former case, it's fine to use the tuner on your coax fed antenna. In the latter, it's absurd. ......................................................... I agree with you 100 percent, there is a time and place for an antenna tuner on coax. But remember W4LGH said The idea of an antenna tuner hooked to an un-balanced line (coax) is absurd. And w4LGH said the reason they put antenna tuners in radios is so F#$KING IDIOTS like you will BUY THEM!! Statements like that I have a REAL problem with. Stan K9IUQ
K9IUQ2007-02-25
Benchmarks
W4LGH says Damn I hate it when someone pushes me into calling them names, but I guess if the shoe fits...

...................................................
I can see you need help with this Al and I will help. The next time you get mad at somebody because they don't agree with you and they aint a 'Broadcast Engineer" so how could they ever know as much as you? And you feel the need to use words that have NO place on eham, IGNORE the person. Trust me Al, ignoring them will do wonders for you.You will not feel the need use those nasty words - that have NO place on a eham forum.


I tried to warn you Al. Many Posts back,I said "Better to Be Thought a Fool, than to open your mouth and Prove it." But you just wouldnt listen.

You have proved yourself many times over Al, great Job..

K9IUQ
K9IUQ2007-02-25
RE: Benchmarks
W4GLH continues with his ranting: You made the statemant if tuners weren't any good, why did they put them in radios?


K9IUQ says without vulgarity: Don't try to spin what I say, like you do with your comments. You want to quote what I say in past posts, fine.

Since you don't seem to know how to use the find key in a Browser, here is what was said word for word NO SPIN and DIRECT QUOTES:
..................
You W4LGH said: The idea of an antenna tuner hooked to an un-balanced line (coax) is absurd


And K9IUQ replied : If this was true we wouldn't have built-in antenna tuners in our rigs.

Stan K9IUQ


Reply to a comment by : W4LGH on 2007-02-25

Stan K9IUQ wrote.. But remember W4LGH said The idea of an antenna tuner hooked to an un-balanced line (coax) is absurd. And w4LGH said the reason they put antenna tuners in radios is so F#$KING IDIOTS like you will BUY THEM!! Statements like that I have a REAL problem with. ================ Why is that Stan, did you just learn you are a F#^KING IDIOT? Would you like some cheese to go with that wine? W4LGH said this and W4LGH said that... Jesus H Crist Stan...GROW UP! You made the statemant if tuners weren't any good, why did they put them in radios? If that statement is the basis of your logic, I rest my case! Damn I hate it when someone pushes me into calling them names, but I guess if the shoe fits...
Reply to a comment by : KC8QFP on 2007-02-25

There was a discussion on the ""Where will Ham Radio be 50 Years from Now"" about remote control wireless link between the shack and tower, i.e. no more need for feedline! You'd have a control head or PC remote that might use IR, low powered RF, or LASER to send signals to the tower for xceiver remote control, rotor, and perhaps even linear. So the tower would onlyneed a power source (120/220VAC 10g line). They do this with X-10 cameras, I was thinking about mounting one of those up on my tower. A simple way to direct couple the transmitter to the antenna! WOW! I sure would like to see TenTec or Drake make such a rig! YaeComWood already has full spectrum HT's, and TenTec has a PC controlled xceiver, with a few mods, this would be a great RC rig (if it has a USB port). I sure would like to see Drake get back into ham radio with such a rig! 73, Don
Reply to a comment by : K9IUQ on 2007-02-25

N3OX says It's also a *fact* that feeding a 20m dipole on 40m (14-j1000) through 30 feet of RG-8/X coax leads to 16dB feedline loss. Both of these cases (good coax, 5:1 SWR and common, cheap coax, 670:1 SWR) are encountered in amateur radio every day. The first one by people who are sensibly trying to stretch the frequency coverage of their 75m/80m dipole without complicated tricks at the antenna, and the latter by people who find that they can "find a match" on 40m with their 20m dipole and they can hear stations. In the former case, it's fine to use the tuner on your coax fed antenna. In the latter, it's absurd. ......................................................... I agree with you 100 percent, there is a time and place for an antenna tuner on coax. But remember W4LGH said The idea of an antenna tuner hooked to an un-balanced line (coax) is absurd. And w4LGH said the reason they put antenna tuners in radios is so F#$KING IDIOTS like you will BUY THEM!! Statements like that I have a REAL problem with. Stan K9IUQ
W4LGH2007-02-25
RE: Benchmarks
Stan K9IUQ wrote..

But remember W4LGH said The idea of an antenna tuner hooked to an un-balanced line (coax) is absurd. And w4LGH said the reason they put antenna tuners in radios is so F#$KING IDIOTS like you will BUY THEM!!

Statements like that I have a REAL problem with.
================

Why is that Stan, did you just learn you are a F#^KING IDIOT? Would you like some cheese to go with that wine? W4LGH said this and W4LGH said that...

Jesus H Crist Stan...GROW UP! You made the statemant if tuners weren't any good, why did they put them in radios? If that statement is the basis of your logic, I rest my case!

Damn I hate it when someone pushes me into calling them names, but I guess if the shoe fits...
Reply to a comment by : KC8QFP on 2007-02-25

There was a discussion on the ""Where will Ham Radio be 50 Years from Now"" about remote control wireless link between the shack and tower, i.e. no more need for feedline! You'd have a control head or PC remote that might use IR, low powered RF, or LASER to send signals to the tower for xceiver remote control, rotor, and perhaps even linear. So the tower would onlyneed a power source (120/220VAC 10g line). They do this with X-10 cameras, I was thinking about mounting one of those up on my tower. A simple way to direct couple the transmitter to the antenna! WOW! I sure would like to see TenTec or Drake make such a rig! YaeComWood already has full spectrum HT's, and TenTec has a PC controlled xceiver, with a few mods, this would be a great RC rig (if it has a USB port). I sure would like to see Drake get back into ham radio with such a rig! 73, Don
Reply to a comment by : K9IUQ on 2007-02-25

N3OX says It's also a *fact* that feeding a 20m dipole on 40m (14-j1000) through 30 feet of RG-8/X coax leads to 16dB feedline loss. Both of these cases (good coax, 5:1 SWR and common, cheap coax, 670:1 SWR) are encountered in amateur radio every day. The first one by people who are sensibly trying to stretch the frequency coverage of their 75m/80m dipole without complicated tricks at the antenna, and the latter by people who find that they can "find a match" on 40m with their 20m dipole and they can hear stations. In the former case, it's fine to use the tuner on your coax fed antenna. In the latter, it's absurd. ......................................................... I agree with you 100 percent, there is a time and place for an antenna tuner on coax. But remember W4LGH said The idea of an antenna tuner hooked to an un-balanced line (coax) is absurd. And w4LGH said the reason they put antenna tuners in radios is so F#$KING IDIOTS like you will BUY THEM!! Statements like that I have a REAL problem with. Stan K9IUQ
KC8QFP2007-02-25
RE: Benchmarks
There was a discussion on the ""Where will Ham Radio be 50 Years from Now"" about remote control wireless link between the shack and tower, i.e. no more need for feedline! You'd have a control head or PC remote that might use IR, low powered RF, or LASER to send signals to the tower for xceiver remote control, rotor, and perhaps even linear. So the tower would onlyneed a power source (120/220VAC 10g line). They do this with X-10 cameras, I was thinking about mounting one of those up on my tower. A simple way to direct couple the transmitter to the antenna! WOW! I sure would like to see TenTec or Drake make such a rig! YaeComWood already has full spectrum HT's, and TenTec has a PC controlled xceiver, with a few mods, this would be a great RC rig (if it has a USB port). I sure would like to see Drake get back into ham radio with such a rig!

73, Don
Reply to a comment by : K9IUQ on 2007-02-25

N3OX says It's also a *fact* that feeding a 20m dipole on 40m (14-j1000) through 30 feet of RG-8/X coax leads to 16dB feedline loss. Both of these cases (good coax, 5:1 SWR and common, cheap coax, 670:1 SWR) are encountered in amateur radio every day. The first one by people who are sensibly trying to stretch the frequency coverage of their 75m/80m dipole without complicated tricks at the antenna, and the latter by people who find that they can "find a match" on 40m with their 20m dipole and they can hear stations. In the former case, it's fine to use the tuner on your coax fed antenna. In the latter, it's absurd. ......................................................... I agree with you 100 percent, there is a time and place for an antenna tuner on coax. But remember W4LGH said The idea of an antenna tuner hooked to an un-balanced line (coax) is absurd. And w4LGH said the reason they put antenna tuners in radios is so F#$KING IDIOTS like you will BUY THEM!! Statements like that I have a REAL problem with. Stan K9IUQ
N3OX2007-02-25
RE: Benchmarks
Stan,

I sent an email to you at your listed address on qrz.com... if that's no good, can you send me one at n3ox.dan@gmail.com?

Dan
Reply to a comment by : N3OX on 2007-02-25

" Statements like that I have a REAL problem with. " Agreed.
Reply to a comment by : K9IUQ on 2007-02-25

N3OX says It's also a *fact* that feeding a 20m dipole on 40m (14-j1000) through 30 feet of RG-8/X coax leads to 16dB feedline loss. Both of these cases (good coax, 5:1 SWR and common, cheap coax, 670:1 SWR) are encountered in amateur radio every day. The first one by people who are sensibly trying to stretch the frequency coverage of their 75m/80m dipole without complicated tricks at the antenna, and the latter by people who find that they can "find a match" on 40m with their 20m dipole and they can hear stations. In the former case, it's fine to use the tuner on your coax fed antenna. In the latter, it's absurd. ......................................................... I agree with you 100 percent, there is a time and place for an antenna tuner on coax. But remember W4LGH said The idea of an antenna tuner hooked to an un-balanced line (coax) is absurd. And w4LGH said the reason they put antenna tuners in radios is so F#$KING IDIOTS like you will BUY THEM!! Statements like that I have a REAL problem with. Stan K9IUQ
N3OX2007-02-25
RE: Benchmarks
"
Statements like that I have a REAL problem with. "

Agreed.
Reply to a comment by : K9IUQ on 2007-02-25

N3OX says It's also a *fact* that feeding a 20m dipole on 40m (14-j1000) through 30 feet of RG-8/X coax leads to 16dB feedline loss. Both of these cases (good coax, 5:1 SWR and common, cheap coax, 670:1 SWR) are encountered in amateur radio every day. The first one by people who are sensibly trying to stretch the frequency coverage of their 75m/80m dipole without complicated tricks at the antenna, and the latter by people who find that they can "find a match" on 40m with their 20m dipole and they can hear stations. In the former case, it's fine to use the tuner on your coax fed antenna. In the latter, it's absurd. ......................................................... I agree with you 100 percent, there is a time and place for an antenna tuner on coax. But remember W4LGH said The idea of an antenna tuner hooked to an un-balanced line (coax) is absurd. And w4LGH said the reason they put antenna tuners in radios is so F#$KING IDIOTS like you will BUY THEM!! Statements like that I have a REAL problem with. Stan K9IUQ
K9IUQ2007-02-25
Benchmarks
N3OX says It's also a *fact* that feeding a 20m dipole on 40m (14-j1000) through 30 feet of RG-8/X coax leads to 16dB feedline loss.

Both of these cases (good coax, 5:1 SWR and common, cheap coax, 670:1 SWR) are encountered in amateur radio every day. The first one by people who are sensibly trying to stretch the frequency coverage of their 75m/80m dipole without complicated tricks at the antenna, and the latter by people who find that they can "find a match" on 40m with their 20m dipole and they can hear stations.

In the former case, it's fine to use the tuner on your coax fed antenna. In the latter, it's absurd.
.........................................................

I agree with you 100 percent, there is a time and place for an antenna tuner on coax.

But remember W4LGH said The idea of an antenna tuner hooked to an un-balanced line (coax) is absurd. And w4LGH said the reason they put antenna tuners in radios is so F#$KING IDIOTS like you will BUY THEM!!

Statements like that I have a REAL problem with.

Stan K9IUQ










K9IUQ2007-02-25
Benchmarks
KU2US says So put em' up, use them and be happy..

........................................................

Truer words were never said about antennas. You could put up a text- book antenna and it might work better (or worse) than predicted because of things you cant control - like the surrounding environment. This whole thread has shown me that hams take antennas way to seriously. Do the best you can making and putting up antenna and dont worry if you cant get it textbook perfect. let me tell you a little story, that the oldtimers here will smile about..

Back around 1960 a young lad of 14 got a novice license. He didnt have much money, a paper route didnt pay much back then. He scraped up enough money to buy an Eico 720 kit and put it together. He didnt have any money for a Receiver, but after much begging his mother bought a Hammarlund HQ 100 on time payments - provided he paid for it out of his paper route money. This young lad was friends with the local TV Repairman who had a shop in town. EVERY day after school the lad would stop and talk to his tv repairman friend. The TV guy gave the lad parts, just all kind of good things. The Lad talked TV Guy into giving him some used 300 ohm tv line. this was the reall cheap stuff that no one would buy today. The lad also got some used wired and a knife switch from the tv guy.

Now the Lad had everything for a station. He read all the antenna info he could and decided to put up a 130 wired fed in the center with the 300 ohm used elcheapo tv twinlead. He hooked the tv line up the the knife switch. This was so the Lad could go from rx to tx. The Eico 720 had a coax input, what to do. The lad couldnt afford coax, it was way exp$pen$ive back in 1960. So he talked his TV repairmen into getting him a pl259 cheep.

The lad soldered the pl259 onto the tv line and screwed into the xmtr. Didnt have no internal antenna tuner, no the EICO just had a pi-network. Now if this lad would of had internet he would had 10 hams tell him that this just wasnt gonna work, no its against the laws of nature. But in 1960 internet was not around and the lad wasnt smart enough, (he was only 14 remember,) to know this antenna wasnt going to work.

So the lad proceeded to work nearly 35 countries and made WAS with this antenna as a novice. Did I say that novices could only use crystals back then and the lad only had 2 crystals. Good thing that lad didnt have internet, he wouldnt tried and worked all that stuff called dx. I mean everyone knows you cant use cheap used 300ohm tv line on an antenna.

This lad is smart now, he has learned never to believe much on the internet.

He still does dumb things like use a Tuner with coax, make non-resonant antennas and feed them with 600 ohm feeders (he doesnt use tv line any more tho).


Stan K9IUQ - ROTFL
















N3OX2007-02-25
RE: Benchmarks
K9IUQ, I agree with everything you're saying, like:

"Couple that with the FACT that even at a 5:1 SWR on GOOD coax you will only lose maybe 1db "

However, I think we have to be careful and not entirely dismiss W4LGH's statement that hooking coax to the output of a tuner is absurd.

It's also a *fact* that feeding a 20m dipole on 40m (14-j1000) through 30 feet of RG-8/X coax leads to 16dB feedline loss.

Both of these cases (good coax, 5:1 SWR and common, cheap coax, 670:1 SWR) are encountered in amateur radio every day. The first one by people who are sensibly trying to stretch the frequency coverage of their 75m/80m dipole without complicated tricks at the antenna, and the latter by people who find that they can "find a match" on 40m with their 20m dipole and they can hear stations.

In the former case, it's fine to use the tuner on your coax fed antenna. In the latter, it's absurd.

I'd say that people that do the former tend to know what the ramifications of doing so are... they lose a dB in the coax as an educated tradeoff for limiting the complexity of the antenna. They, like you, read W4LGH's statement and say "wait a minute, it's no problem in my case"

People that do the latter almost certainly don't know that they're losing 16dB in the coax. They don't realize that they'd radiate 40 times the power if they just put up a 40m antenna. They may benefit strongly from a blanket statement like "don't use coax on the output of your tuner!"

We probably should stay away from overly generic rules of thumb about coax on the output of tuners, but if we have to pick, I'd pick "Don't EVER do it" because once you know the ramifications of doing it, you can make educated decisions about whether or not it's a good idea, but until you know, you'll have a better signal if you just avoid it entirely.

To that end (making educated decisions), I'll post my favorite transmission line calculator:

http://vk1od.net/tl/tllc.php

Stocked with many different flavors of transmission line, from homebrew open wire to window line, from RG-174 to heliax... will accept SWR as a mismatch or impedance in R+jX form for better accuracy. Gives you the SWR and impedances at the load, at the transmitter, and line loss.

73,
Dan
Reply to a comment by : K9IUQ on 2007-02-25

N0EW says I've only measured the losses through my medium quality transmatch a couple times (Mighty Fine Junk, MFJ-949E), but they have only been about 1dB loss. A little less than than in most cases. Almost no one can hear a 2dB loss in signal, let along a 1dB loss. ........................................................ I wonder how you arrived at the db figures? QST magazine does antenna tuner reviews regularly. They use % power lost in their antenna tuner review charts. These reviews are available to members on the ARRL Website. My Tuner is a Ten-Tec 238B which tested by them shows a 5-10 percent loss depending on the band. It seems like a 10 watt loss (with a 100 watt xmtr) is a small price to pay for a tuner. Couple that with the FACT that even at a 5:1 SWR on GOOD coax you will only lose maybe 1db - Referenced from Fig 1.1 "Refections" by Walter Maxwell. My Multiband wire antennas use open wire feedline, however I have a LoG Periodic which is Coax fed. This antenna has a 2:1 or little less SWR thruout its 14-30mhz range. I use a tuner with this antenna so my solidstate radio will put out full power I also have a solidstate amplifier. This amp will NOT tolerate a 2:1 SWR. My TEN-TEC 238B handles the chore nicely. Even tho I might be losing some power in the tuner and some in the coax, it doesnt seem to make much difference. I find the 100 wts or the Amp on does just fine on DX, Most of the other Tuners tested by the ARRL show an average of a 15% loss. This much loss can not be detected on the receiving end. If you dont believe me the next time you are running 100 wts ask the other fellow how you sound at 50 watts. Most will say no difference. So when you see really stupid statements like: "The idea of an antenna tuner hooked to an un-balanced line (coax) is absurd." Just keep laughing as you are working the dx.. Stan K9IUQ
KU2US2007-02-25
Benchmarks
WOW! tons of antenna info on this thread. I have two antennas, and use each to reference each other. A G5RV horizontal, and a 5BTV vertical with 9 radials ground mounted. Believe this or not, the G5RV hears better but is noisier than the vertical! I can switch back and forth between antennas in the shack and use the one that hears better to make the QSO. Sometimes I hear a station better on the G5RV, but switch to the vertical to transmit, back and forth, a pain I know, but it works. The XF2 station (New IOTA) I grabbed using the vertical, the G5RV was to noisy! The vertical is fed with 100' of RG8X to a tuner. Same with the G5RV but with 50' of coax. I know there is loss, but I made the contact, and that is what matters to me. I also have a Kenwood R-1000 reciever and SWL with it. I use the G5RV for this-it works great! The vertical is useless for SWL. Here is a Kicker, I also DX AM broadcast band AM stations. The vertical KILLS the G5RV, even though the "RV" is much longer in size (102') maybe vertical polarization of the broadcast stations antenna? So you see, all of these antenna calculations, theories, books, algebra, and opinions are relevent to making a good working antenna, BUT, all together this depends on one thing to work-MOTHER NATURE...propagation, sunspots, soil conductivity, ground, weather. things we cannot control, no matter how mathematically correct your antenna is. So put em' up, use them and be happy..
K9IUQ2007-02-25
Benchmarks
N0EW says I've only measured the losses through my medium quality transmatch a couple times (Mighty Fine Junk, MFJ-949E), but they have only been about 1dB loss. A little less than than in most cases. Almost no one can hear a 2dB loss in signal, let along a 1dB loss.

........................................................

I wonder how you arrived at the db figures? QST magazine does antenna tuner reviews regularly. They use % power lost in their antenna tuner review charts. These reviews are available to members on the ARRL Website.

My Tuner is a Ten-Tec 238B which tested by them shows a 5-10 percent loss depending on the band. It seems like a 10 watt loss (with a 100 watt xmtr) is a small price to pay for a tuner. Couple that with the FACT that even at a 5:1 SWR on GOOD coax you will only lose maybe 1db - Referenced from Fig 1.1 "Refections" by Walter Maxwell.

My Multiband wire antennas use open wire feedline, however I have a LoG Periodic which is Coax fed. This antenna has a 2:1 or little less SWR thruout its 14-30mhz range. I use a tuner with this antenna so my solidstate radio will put out full power I also have a solidstate amplifier. This amp will NOT tolerate a 2:1 SWR. My TEN-TEC 238B handles the chore nicely. Even tho I might be losing some power in the tuner and some in the coax, it doesnt seem to make much difference. I find the 100 wts or the Amp on does just fine on DX,

Most of the other Tuners tested by the ARRL show an average of a 15% loss. This much loss can not be detected on the receiving end. If you dont believe me the next time you are running 100 wts ask the other fellow how you sound at 50 watts. Most will say no difference.

So when you see really stupid statements like:

"The idea of an antenna tuner hooked to an un-balanced line (coax) is absurd."

Just keep laughing as you are working the dx..

Stan K9IUQ








K9IUQ2007-02-25
Benchmarks

W4LGH says - The idea of an antenna tuner hooked to an un-balanced line (coax) is absurd.

One TRUE statement was made, a RESONATE antenna will work BETTER than a NON_RESONATE antenna

I have some wonderful ocean front property in Arizona that I want to sell you really CHEAP! And I'll even finance it to you! If you call right now, I'll double this offer...2 acres for the price of one! But you have ato call in the next 10 minutes, have your CREDIT CARD READY!

No matter how well you try to write something they always find other things to read into it.

read what I said.

maybe a failure to communicate or lost in the translations

the reason they put antenna tuners in radios is so F#$KING IDIOTS like you will BUY THEM!!

No one understands friendly debate

.....................................................

Yes Al, you do have quite a way with words. You have communicated quite well, I mean when someone calls you a F**ing Idiot, its pretty clear. Yep , you been one friendly fellow too.

I found it interesting that in the discourse here, only you felt it necessary to attack character and use vulgarity to get your point across. You got your point across quite well judging from all the hams dismissing you.

K9IUQ -LMAO

N0EW2007-02-25
RE: Benchmarks
W4LGH:

I've only measured the losses through my medium quality transmatch a couple times (Mighty Fine Junk, MFJ-949E), but they have only been about 1dB loss. A little less than than in most cases. Almost no one can hear a 2dB loss in signal, let along a 1dB loss. (I'm tempted to say no one can, but I'll not go quite that far, as there are exceptional ears out there far and few apart.)

I think you are being over zealous in your characterzation of using a transmatch, even with coax. There is nothing inherently wrong with such a choice. Especially if the coax run is short, and the quality of the coax is good to high. (I too like LMR 400, or RG-213 type coax. But I'll use RatShack coax if either the need is immediate or the run is only a foot or two.)

Now I was transmitting into a "reasonable" antenna (either a non-resonate dipole being pushed out-of-band, or a 200+ foot horizontal loop above my house, in most cases). "Reasonalbe" of course is open to wide debate. In my case I simply mean reasonable to be an otherwise resonate antenna being used on bands for which it was not primarily designed to used upon.

By "reasonable" is do NOT mean such things as Lawn Chairs sitting on my roof (DX: Cape Verde, Africa), metal tape measures laying across my roof (DX: Kyrgyzstan) -which actually makes for a pretty good antenna in a pinch- or a chicken wire / trampoline semi-vertical antenna (DX: Italy and Germany). I would expect the transmatch losses may be higher forcing such strange things to work as antennas. However, work, they did.

The main thrust of Alan's article -in my opinion- is that we are dealing with antenna SYSTEMS and that any one number we care to observe (be it swr, output current, antenna gain, etc, etc, ad nausium) is in-and-of-itelf totally useless.

Said number(s) we care to observe are ONLY important after we take into consideration the interaction of all the components comprising the antenna SYSTEM. Only after taking into account this larger picture may we properly evaluate the meaningfulness (or lack thereof) of the chosen number(s).

Or to be brief:

Unqualified worship of any favorite number is folly.

Such are my beliefs. Add several bucks and you can get yourself an over-priced coffee (which, as with a perfect 1:1 swr, _must_ mean it is good!)

73-Erik n0ew
Reply to a comment by : W4LGH on 2007-02-22

This is a very interesting article, and touches on many points. The first is antenna GAIN. Altho I understand the principle very well, including how this gain is achieved, by beaming the radiated power more directional, I have always found the idea of saying an antenna has gain to be an oxymoron. When in fact an antenna (passive) can NOT produce any gain, it can however have less loss, but nothing is FREE, and once again compromises are made to get this gain. Another subject touched, DBI and DBD. Since you can NOT build an isotropic antenna on earth, and to my knowledge they haven't built one in free space yet, I find DBI to be an invalid rating and useless. DBD however is a more valid rating and since we CAN build dipoles on earth to compair to, the rating is more realistic. However you'll hardly ever is a DBD rating on an antenna. The idea of an antenna tuner hooked to an un-balanced line (coax) is absurd. The only thing you are tuning is the impedance at the shack end of the coax. The mis-match at the antenna still exsists and is still very REAL!! It may allow you to do something you couldn't without it, but you are only fooling yourself! Not to mention the other factor touched on, loss in the tuner..the best tuner made will have between an 11% to 15% loss!! Some of the cheaper tuners go way higher, as much as 40%!! Now you take your ant that has a 3:1 swr ratio, which is about a 25% loss, 3db loss in your coax, and a 15% loss in your tuner. Your meter on the tuner now shows 1:1 swr, output from your radio is showing a full 100watts, and you are HAPPY, but actually here is what you have...approx. 100-15(tuner loss)=85-42.5(3dbcoax)=42.5-10.5(3:1swr)= 32 watts!!! 1/3 of your power is being radiated!!! Not very good, but your meter says 100watts and you are happy. You will NOT find a tuner in use in my shack! I own a little MFJ941E piece of junk, but was using it to match a long wire to a receiver. Those figures above also work on your receiver too! Altho quite different, there is a big loss in your receive signal as well. Hope all this gives you something to think about. Al of my antennas are resonate, and are fed with LMR-400 cable (basically no loss @ HF) I have measured my power leaving the shack @ 100watts, and at the antenna there will be 98watts! This was done not so much for transmit, but for the receive side. If you can't hear them, you CAN NOT talk to them!!!! I do NOT claim my figures to be 100% accurate, but close enough to show an example of whats happening. 73 de W4LGH - Alan http://www.w4lgh.com
Reply to a comment by : NORTHCOUNTRY on 2007-02-22

My ant is monoband resonant on 40m but I use a tuner anyway. The tuner does not tune it on any other band. Picture here: http://i32.photobucket.com/albums/d43/Tom838/3-500Z%20pics/40mant.jpg
KY1V2007-02-24
RE: Benchmarks
N0AH wrote:

"anything else?"

If your insist on sticking your big toe into the gator cage, it will likely get bit...and you will have deserved it.

In other words, stop attacking others and you won't get it in return.

If you are in doubt, go back and read EVERY post and find one where I even mentioned your name or call...before you started in on me.


Kapish?

David ~ KY1V

PS: Now we can be friends!
Reply to a comment by : N0AH on 2007-02-24

Started VEC for the Denver Radio Club in 1998. Have taught several classes for new hams in past three years with local church. Served in Mississippi with RedCross after Katrina with other hams.Helped in Bridgecreek OK after 1999 tornadoes for 4 weeks- Google it up- . My daughters name is on my QSL card with mine .... anything else?
N0AH2007-02-24
Benchmarks
Geo,

No one is reading this thread any more- it is fished out- But I enjoyed your stuff-

Paul
K0FF2007-02-24
Benchmarks
SWR>
SWR measurements mean little if not applied properly.
Low SWR at the radio end of a coax line does not even indicate that there is an antenna connected at the other end. An open or shorted feedline can read a low SWR is the length to the fault is "tuned" by feedline length. Many antennas deliberately include a shorted stub right at their feedpoint.

Many antennas, like a 1/4 wave vertical are not 50 Ohm antennas. If you have a perfect SWR on an HF 1/4 wave vertical, the difference in the real antenna feedpoint impedance ( 20-28 Ohms) and the 50 Ohms you THINK you are seeing is the ground impedance. Try a wire Vert with 4 radials. Fed with 50 coax, shows 1:1 SWR. Add some more radials, watch the SWR climb. Why? You are reducing the ground portion of the impedance. Here is the classic case of "Low SWR for the WRONG Reason". See Maxwell's "REFLECTIONS". The HIGHER SWR version of the antenna will have a better efficiency than the lower SWR version.
Some of my antennas are designed to be fed with 75 Ohm coax. One reason is that the Ohmic losses are less than 50 Ohm cable. If the antenna system is fed from a tube type amplifier, the radio end will notice no differences. If fed by a solid state radio, this is one of the few reasons I would consider a rig mounted tuner useful, The other is to better match the broadband input of a tube amplifier, allowing more drive to be generated, and a better quality of signal to be transmitted.

DB> My antenna systems are designed for 1 dB feedline loss, and since I have many towers at different distances from the shack, each is designed for different frequencies and has different feedline. Some have 1-5/8 Heliax to keep the loss low. Others have 1-1/4” Heliax, 7/8” Heliax or ½” Heliax. For receive antennas, preamps are put at the antenna end where needed. Antennas themselves are designed more for angle of takeoff than max gain, although gain is important too. Sometimes stacking antennas is the only way to get the desired gain, but in general a single large antenna is better than the equivalent stacked antenna, as long as the stacking wasn’t for angle of takeoff optimization in the first place. Power is lost in the db factor of feedlines, no doubt about that. Transmit AND receive power.

Comparing different antennas> Just because one antenna works better than another IN A CERTAIN INSTANCE does not make it a better antenna. We Hams overlook ANGLE of Radiation way too much. It is a VERY important parameter when dealing with propagation. I have a variety of antennas, each is optimized for a different type of propagation mode. A long-haul low angle DX antenna with tremendous front-to-back ratio is not as good as a low mounted tribander, for certain applications. On 6 and 10 meters, your antennas can easily be TOO HIGH up in the air to take advantage of the prevailing DX conditions, while at other times, only the high mounted antenna will produce results at all ( Es Vs. F2). On other cases a NVIS antenna is preferred. It just depends on what your intended use is for the antenna.

Resonance: HAHA. Think a 3/8 X vert on 160 or a 5/8 on 40 aren't band busters? Yep the sure are, and they are not resonant. By the same token, try your 19 inch 2 Meter mobile n 440, It's a 3/4 wave and works great. True "Long wires", V beams, Rhombics and other “wave antennas” do not need to be resonant at all, still they work great. Don't confuse a wire that is long ( actually a random wire) with a LONGWIRE antenna.

Antenna Tuners> There are such things. Modern Ham radios do not have them. They have instead a "Coax Line Flattener". AN ANTENNA TUNER MUST BE AT THE ANTENNA. In the olden days, the antenna tuner was in the rig because the antenna started at the rig's antenna terminal. That piece of wire between the radio and the outside portion is part of the antenna. I have numerous photos of my shipboard radio operations that clearly demonstrate this feature. The 3/8 inch copper tubing-wire starts at the output terminal, goes by way of HV standoffs and feedthrough to the outside "flatop". Works great, just don't touch the feedwire! By the way, there is receive loss in internal tuners, especially on upper bands, check it out on marginal signals. Never use a tuner on 6M!

Grounding> Grounding and counterpoise are two different concepts. A radio station should be set up with a single-point-ground system. I personally treat counterpoises as a non-grounded antenna component. They are resonant and isolated from the earth. Grounding at the antenna has little to do with performance but everything to do with safety. I ground each tower leg to its own ground rod, tie all the ground rods together.
Coax leaving a tower should come all the way down to the ground before leaving the area. Even if the tower is right next to the house, the coax should go to the ground first. If it is absolutely necessary for the coax to leave the tower at some point above ground, e.g. for loss reduction, the shield part of the coax should be tapped and continue to ground at the tower. Same deal with rotor wires. A point only 10 feet above the ground could easily be at 10’s of thousands of Volts in a lightning strike.

Reciprocal?> Antennas are generally considered to be reciprocal but that does not mean that the
same antenna that might be good for transmitting will be best for receiving or visa-versa. Beverage and Loop antennas are great for receiving but make lousy DX transmit antennas. We usually use a Beverage on 160-80-40 receive and some sort of vertical for transmit ( LOW angle for DX, remember?)

Here’s MY BENCHMARKS:

Geo >K0FF
Original issue, not vanity
6M DXCC, WAS, WAC, WAZ#7
Only 160-6M DXCC in the Zero district
#1 W0 6M DXCC
#1 W0 to reach 336 countries
2M WAS, WAC, 35 countries
First Class FCC Radiotelephone/Radar
Life Member ARRL, AMSAT, NRA
SETI Honor Roll#1
DXCC Honor Roll #1 @337/351
N0AH2007-02-24
Benchmarks
Started VEC for the Denver Radio Club in 1998. Have taught several classes for new hams in past three years with local church. Served in Mississippi with RedCross after Katrina with other hams.Helped in Bridgecreek OK after 1999 tornadoes for 4 weeks- Google it up- . My daughters name is on my QSL card with mine .... anything else?
KY1V2007-02-24
RE: Benchmarks
Paul,

After 33 years of Ham radio, I think I have you beat...I have no (0) awards at all!

Chasing paper, such as 5BDXCC, 5BWAZ and the like is DULL!

I wouldn't even have the contest plaques if they didn't simply send them to me.

FYI, being a real ham isn't based on ones DXCC status.

Now, when you start an original program to help youth experience ham radio in some way not otherwise possbile for them, I will be impressed! I may even nominate you for Ham of the Year!

David ~ KY1V

PS:

Trancievers at 6Y1V: 60K+

Entire station at 6Y1V: 250K+

Reading N0AH's rhetoric on eHam: Priceless


Reply to a comment by : N0AH on 2007-02-24

KY1V: Here is a benchmark for you.....as soon as you have finished your 5BWAZ (200 that is) I'll just let you yack............if you have not noticed lately, I think we are the last two left on thread. Your Compradre, Paul 200 5BWAZ which is the only thing I have to hang from my wall....BTW, I've racked up over 46,000 miles on my DX'pedition travels. What's left? Oh yeah, I killed a snake on Lord Howe island abot to attack a native Laweelacker. Be Michael jackson and Beat That-
N0AH2007-02-24
Benchmarks
KY1V:

Here is a benchmark for you.....as soon as you have finished your 5BWAZ (200 that is) I'll just let you yack............if you have not noticed lately, I think we are the last two left on thread.

Your Compradre,

Paul 200 5BWAZ which is the only thing I have to hang from my wall....BTW, I've racked up over 46,000 miles on my DX'pedition travels. What's left? Oh yeah, I killed a snake on Lord Howe island abot to attack a native Laweelacker. Be Michael jackson and Beat That-

KY1V2007-02-24
RE: Benchmarks

By the way, the website, photos, QSL cards...it's all fake...just to try and fool you.

You got me man!

David ~ KY1V

Sorry, it's now KY1Y...even my call is faux!
Reply to a comment by : KY1V on 2007-02-24

N0AH wrote: "From all of your bravado- maybe you should just stay at home during the next contest and listen on how real contestors operate- That should act as a good bench mark for you- From the sounds of it, you wasted a lot of time in managing your pile ups- Its like the more you spout, the bigger the holes in your story become.......Did you really go to 6Y?" Tell me again? How do your stacks work? LOL While you're at it...please define a real contester! Last time I checked, I put several new plaques on the wall! I manage my pileups just fine. I don't let the Italians run over me like most inexperienced ops...and the US guys are the most polite, even standing by for a half hour to let me squeeze in a small pileup of Asian stations. But you on the other hand, seem to think you are an expert on everything and make conclusions that are completely incorrect, such as your silly remarks about my log, whom I was referring to in a previous post and now your question as to whether or not I ever go to 6Y. What a dot! Lay off the {insert chemical of choice here} man! David ~ KY1V
Reply to a comment by : N0AH on 2007-02-24

KY1Y: From all of your bravado- maybe you should just stay at home during the next contest and listen on how real contestors operate- That should act as a good bench mark for you- From the sounds of it, you wasted a lot of time in managing your pile ups- Its like the more you spout, the bigger the holes in your story become.......Did you really go to 6Y?
KY1V2007-02-24
RE: Benchmarks

N0AH wrote:

"From all of your bravado- maybe you should just stay at home during the next contest and listen on how real contestors operate- That should act as a good bench mark for you- From the sounds of it, you wasted a lot of time in managing your pile ups- Its like the more you spout, the bigger the holes in your story become.......Did you really go to 6Y?"

Tell me again? How do your stacks work? LOL

While you're at it...please define a real contester!

Last time I checked, I put several new plaques on the wall!

I manage my pileups just fine. I don't let the Italians run over me like most inexperienced ops...and the US guys are the most polite, even standing by for a half hour to let me squeeze in a small pileup of Asian stations.

But you on the other hand, seem to think you are an expert on everything and make conclusions that are completely incorrect, such as your silly remarks about my log, whom I was referring to in a previous post and now your question as to whether or not I ever go to 6Y. What a dot!

Lay off the {insert chemical of choice here} man!

David ~ KY1V


Reply to a comment by : N0AH on 2007-02-24

KY1Y: From all of your bravado- maybe you should just stay at home during the next contest and listen on how real contestors operate- That should act as a good bench mark for you- From the sounds of it, you wasted a lot of time in managing your pile ups- Its like the more you spout, the bigger the holes in your story become.......Did you really go to 6Y?
N3OX2007-02-24
RE: Benchmarks
"Did you really go to 6Y?"

I've worked 6Y1V.
Reply to a comment by : N0AH on 2007-02-24

KY1Y: From all of your bravado- maybe you should just stay at home during the next contest and listen on how real contestors operate- That should act as a good bench mark for you- From the sounds of it, you wasted a lot of time in managing your pile ups- Its like the more you spout, the bigger the holes in your story become.......Did you really go to 6Y?
N0AH2007-02-24
Benchmarks
KY1Y:

From all of your bravado- maybe you should just stay at home during the next contest and listen on how real contestors operate- That should act as a good bench mark for you- From the sounds of it, you wasted a lot of time in managing your pile ups- Its like the more you spout, the bigger the holes in your story become.......Did you really go to 6Y?
W4LGH2007-02-24
RE: Benchmarks
KC8QFP wrote..."but some people love to mince words on here."

How well I know that. No matter how well you try to write something they always find other things to read into it.

73 de W4LGH - Alan
http://www.w4lgh.com
Reply to a comment by : KY1V on 2007-02-24

N0AH Wrote: "KY1V and you are giving me a hard time about my call sign. Those who really know me tend to focus on the AH. So lets just keep the issues about our call signs separate- And thanks for the congrads on my extra ticket. I got that kind when I took a 20WPM CW test, written exam,you know.....those days." If you weren't so egotistical, you might have actually noticed the person I was teasing about the call sign and complimenting on getting their extra class license was WG8Z...NOT YOU! WG8Z wrote: "...130' #14awg thhn, Garbage picked..." To which KY1V wrote: "Yeah, that's how I want to spend my weekends, picking through garbage for antenna wire... By the way, nice vanity call...no wonder you couldn't afford wire!!! Perhaps next time move to Wales and go for GW4A.. "Garbage Wire 4 Antenna" wait... maybe Sicily...special event call... IS2D... "I Saved 2 Dollars" Oh, and don't get your panties in a wad...I am just joking! Congrats on getting your Extra class ticket!" David ~ KY1V
Reply to a comment by : KY1V on 2007-02-24

ooops.... "My logs are quite telling...if you knew anything about at all antennas." Should be... My logs are quite telling...if you knew anything at all about antennas.
Reply to a comment by : KY1V on 2007-02-24

N0AH wrote: "KY1V: Your 6Y log is pointless...blah blah...Why do you think lower yagi's on a stacked tower hear DX in the early morning better than the higher yagi's above." It is quite obvious that you don't have stacked yagis! My logs are quite telling...if you knew anything about at all antennas. Keep up the great work with the fan dipoles guys...lmao! David ~ KY1V
Reply to a comment by : N0AH on 2007-02-23

KY1V: Your 6Y log is pointless. This is my two cents. The chances of your angle of radiation going out at the same angle of radiation coming in is slight. Maybe close, but not exact. Why do you think lower yagi's on a stacked tower hear DX in the early morning better than the higher yagi's above. I guess we could all get Moon-Raker 4's to solve the issue.
KY1V2007-02-24
RE: Benchmarks
N0AH Wrote:

"KY1V and you are giving me a hard time about my call sign. Those who really know me tend to focus on the AH. So lets just keep the issues about our call signs separate-

And thanks for the congrads on my extra ticket. I got that kind when I took a 20WPM CW test, written exam,you know.....those days."


If you weren't so egotistical, you might have actually noticed the person I was teasing about the call sign and complimenting on getting their extra class license was WG8Z...NOT YOU!



WG8Z wrote:

"...130' #14awg thhn, Garbage picked..."



To which KY1V wrote:

"Yeah, that's how I want to spend my weekends, picking through garbage for antenna wire...

By the way, nice vanity call...no wonder you couldn't afford wire!!!

Perhaps next time move to Wales and go for GW4A.. "Garbage Wire 4 Antenna"

wait...

maybe Sicily...special event call...

IS2D... "I Saved 2 Dollars"

Oh, and don't get your panties in a wad...I am just joking!

Congrats on getting your Extra class ticket!"



David ~ KY1V
Reply to a comment by : KY1V on 2007-02-24

ooops.... "My logs are quite telling...if you knew anything about at all antennas." Should be... My logs are quite telling...if you knew anything at all about antennas.
Reply to a comment by : KY1V on 2007-02-24

N0AH wrote: "KY1V: Your 6Y log is pointless...blah blah...Why do you think lower yagi's on a stacked tower hear DX in the early morning better than the higher yagi's above." It is quite obvious that you don't have stacked yagis! My logs are quite telling...if you knew anything about at all antennas. Keep up the great work with the fan dipoles guys...lmao! David ~ KY1V
Reply to a comment by : N0AH on 2007-02-23

KY1V: Your 6Y log is pointless. This is my two cents. The chances of your angle of radiation going out at the same angle of radiation coming in is slight. Maybe close, but not exact. Why do you think lower yagi's on a stacked tower hear DX in the early morning better than the higher yagi's above. I guess we could all get Moon-Raker 4's to solve the issue.
KY1V2007-02-24
RE: Benchmarks
ooops....

"My logs are quite telling...if you knew anything about at all antennas."

Should be...

My logs are quite telling...if you knew anything at all about antennas.
Reply to a comment by : KY1V on 2007-02-24

N0AH wrote: "KY1V: Your 6Y log is pointless...blah blah...Why do you think lower yagi's on a stacked tower hear DX in the early morning better than the higher yagi's above." It is quite obvious that you don't have stacked yagis! My logs are quite telling...if you knew anything about at all antennas. Keep up the great work with the fan dipoles guys...lmao! David ~ KY1V
Reply to a comment by : N0AH on 2007-02-23

KY1V: Your 6Y log is pointless. This is my two cents. The chances of your angle of radiation going out at the same angle of radiation coming in is slight. Maybe close, but not exact. Why do you think lower yagi's on a stacked tower hear DX in the early morning better than the higher yagi's above. I guess we could all get Moon-Raker 4's to solve the issue.
KY1V2007-02-24
RE: Benchmarks

N0AH wrote:

"KY1V:

Your 6Y log is pointless...blah blah...Why do you think lower yagi's on a stacked tower hear DX in the early morning better than the higher yagi's above."

It is quite obvious that you don't have stacked yagis!

My logs are quite telling...if you knew anything about at all antennas.

Keep up the great work with the fan dipoles guys...lmao!

David ~ KY1V
Reply to a comment by : N0AH on 2007-02-23

KY1V: Your 6Y log is pointless. This is my two cents. The chances of your angle of radiation going out at the same angle of radiation coming in is slight. Maybe close, but not exact. Why do you think lower yagi's on a stacked tower hear DX in the early morning better than the higher yagi's above. I guess we could all get Moon-Raker 4's to solve the issue.
K9IUQ2007-02-24
Benchmarks
KC8QFP says
Could this be stray RF radiating off the coax? Did you get your cable from Radio Shack? HIHI! Howz about the grounding situation?

.....................................................
According to Alpha Delta's spec sheet there is 60db isolation at 30mhz between antenna inputs.

NO self respecting ham I know uses Radioshat Coax.

Since I operate 160 mtrs with a inverted L antenna my ground system is better than average and includes 4 ground rods and 45 100ft plus radials buried and all tied together.

Stan K9IUQ
KC8QFP2007-02-24
RE: Benchmarks
<<< And I also agree with the poster about speakers and antennas. A speaker to an AF amp is exactly the same as an antenna to an RF amp. The same principles apply only at lower audio frequencies. Everything in life is relative, and there is nothing new under the Sun!

73 de W4LGH Alan
http://www.w4lgh.com >>>

Thank you Alan, at least you seem to get the point I was trying to make. I was NOT saying that speakers are the same as antennaes, but some people love to mince words on here. It's the principal. Now I am going to connect my antenna system to my audio stereo amplifier so I can broadcast music!!! -OR- I suppose that I could connect a 50 ohm speaker to my transmitter so that I can listen to some CW on it!
Howz about this idea, I use an old speaker frame as a parabolic dish for a microwave antenna?

The three "R's":
What is reactance?
What is resonance?
What is resistance?
The "IC's":
What is inductance?
What is impedance?
What is capacitance?
What is conductance?

All these were on the FCC test, let's open this can of worms and see where this discusasion goes? NO cheating guys, react from what you know.

73, Don
Reply to a comment by : W4LGH on 2007-02-23

K0IZ wrote.."Not sure about your long-term broadcast experience, but ... Broadcast band antennas (towers) are rarely (if ever) full 1/4 wave verticals. No problem - a matching network at the base cancels the reactance. Other than slight loss in the network, all of the transmitter power is radiated. THe antenna is NOT resonant, the antenna system IS. So ... several thousand examples." I have been a broadcast engineer for 30+ years, Ham radio and 1st class license for 43+ years. Someone does understand where I have been coming from. Yes Am broadcast towers, except a few at the hi end of the band are less than a 1/4wave. You add a matching network to tune out the reactance, therefore making the antenna system resonant. Hams do the same thing. I also want to set the record staight, that I never said an antenna had to resonant to work, I said it was at it PEAK effeciency at resonance! I have also NEVER mentioned an SWR of 1:1 in order for it to work. My antennas are NOT 1:1 and anything under 3:1 works ok for me. I also said you CAN NOT tune your antenna with an antenna tuner in your shack hooked to un-balanced line(coax). You can however tune the antenna with a tuner or matching network AT the antenna, this is done all the time with load coils, and other matching networks, and these devices are used to make the antenna resonate, which has to do with resonance. And I also agree with the poster about speakers and antennas. A speaker to an AF amp is exactly the same as an antenna to an RF amp. The same principles apply only at lower audio frequencies. Everything in life is relative, and there is nothing new under the Sun! 73 de W4LGH Alan http://www.w4lgh.com
Reply to a comment by : KC8QFP on 2007-02-23

AA4PB sez, ""Think of a matchbox as an output transformer on an amplifier. It matches the impedance of the speaker load to the impedance of the output tubes or transistors. Yes, transformers are still used in commercial audio amplifiers, primarily to match to a 70V distributed paging speaker system."" I would compare an output transformer to a BALUN or torroidial transformer, and not so much the caps and coils that direct the stray RF to ground. An Lpad has a hi-wattage resistor (often coil type) that diverts some of the power through the resistor, and some to the speaker. i.e. a transformer converts as in 4:1 etc., and a matchbox DIVERTS the RF. A matchbox is more akin to filters than transformers. transformers - converts matchbox/filters - diverts Let's say you have a two ohm speaker that you would like to connect to an eight ohm amp. Here are a few ways to do it. One would be to put a six ohm resistor (Lpad/reostat) series inline to the speaker (like a matchbox to me). Another way would be to use a (impedance) transformer (this would be connected in parellel). Another would be to use more speakers in series (my preferred method, like a resonant antenna). Antenna feedline does radiate some of the stray reflected RF, but a lot of it either seeks a path to ground through a tuner or the transmitter. It is called standing wave because it does NOT radiate efficiantly like an antenna. So speaker wire is simular. Radiation and dicipation is simply electricity seeking the lowest path of resistance, i.e. finding its easiest way to complete the circuit. Some finds its way by radiating from an antenna, as RF through space, to the other guys antenna and then through his receiver so to speak. Some energy finds a shortcut to ground through a tuner. The lowest possible path of resistance would be a short circuit because it is the "shortest" or least path of resistance.
Reply to a comment by : AA4PB on 2007-02-23

Speakers and audio amplfiers are quite different than antennas and RF. The wires connecting the speakers are very short in terms of the wavelength of the audio and they do not act as transmission lines. You don't have to deal with standing waves and reflected power on the speaker wires. It is true however that maximum power is transferred from the source to the load when the load impedance matches the source impedance. That's akin to matching the antenna SYSTEM to the transmitter which is why matchboxes are often used. It doesn't relate to resonance of an antenna however. Think of a matchbox as an output transformer on an amplifier. It matches the impedance of the speaker load to the impedance of the output tubes or transistors. Yes, transformers are still used in commercial audio amplifiers, primarily to match to a 70V distributed paging speaker system.
Reply to a comment by : AA4PB on 2007-02-23

Alan, I submit that the ends of a dipole (resonant or not) are ALWAYS open and ALWAYS high impedance. That is exactly what makes the feed impedance of a dipole change as you change its physical length. When each side of a dipole is an exact odd multiple of 1/4 wavelength long then the standing wave on the antenna transforms the high impedance at the end to a fairly low impedance at the center. If the antenna is some other (non-resonant) length then the standing wave transforms the high impedance at the end to some other impedance at the center. As long as you can match that impedance to the feed line you can transfer power into the antenna. If you can transfer power into an antenna then most of it (less the small I*R loss in the resistance of the wire) will be radiated. An antenna has basically two ways to get rid of the power that gets applied to it. Either is is radiated or it is turned to heat. The only thing that can turn it to heat is the resistance of the wire. Since the resistance of the wire in a typical doublet antenna is very low, most of the power must be radiated. Making an antenna a non-resonant length does not change the resistance of the wire therefore it doesn't raise the amount of power disipated as heat by any significant amount.
Reply to a comment by : AD4U on 2007-02-23

Doing something to add 1 or 2 dB to your signal may not make much difference by itself. However if you have the $$ and the time and the expertise, making changes that add a dB here and a dB there and another dB somewhere else, collectively WILL make a noticeable difference. This is often what separates the BIG GUNS from the little pistols.
KC8QFP2007-02-24
RE: Benchmarks
<<< "I think I can hear you on your dummy load"! >>>

Could this be stray RF radiating off the coax? Did you get your cable from Radio Shack? HIHI! Howz about the grounding situation? I have to admit that MFJ "dummy loads" aka rubber duckies might get out a little too.

73 Don

PS: Thank God that we don't use Radio Shack or NFJ as a standard to use as a benchmark.
Reply to a comment by : K9IUQ on 2007-02-24

"I think I can hear you on your dummy load! David ~ KY1V" ...................................................... This actually can happen. A couple years ago the locals were having a conversation on 10 meters. I put the radio into the dummy load to adjust my power. I was heard by several people in a 15 mile range. We made some tests with me transmitting into a dummy load. I was heard perfectly by 4 or 5 hams. At first this really amazed us, I live on a high hill and we figured that was the reason for the good performance of my (MFJ)dummy load. After thinking about it for a while we figured out that *maybe* the reason I was able to be heard on the dummy load was I have my antennas connected thru a Alpha Delta 4 position antenna switch and the dummy load is on the switch too.. Some of the RF was probably leaking thru the switch to my beam....... Stan K9IUQ
K9IUQ2007-02-24
Benchmarks
"I think I can hear you on your dummy load!

David ~ KY1V"
......................................................
This actually can happen. A couple years ago the locals were having a conversation on 10 meters. I put the radio into the dummy load to adjust my power. I was heard by several people in a 15 mile range. We made some tests with me transmitting into a dummy load. I was heard perfectly by 4 or 5 hams. At first this really amazed us, I live on a high hill and we figured that was the reason for the good performance of my (MFJ)dummy load.

After thinking about it for a while we figured out that *maybe* the reason I was able to be heard on the dummy load was I have my antennas connected thru a Alpha Delta 4 position antenna switch and the dummy load is on the switch too.. Some of the RF was probably leaking thru the switch to my beam.......

Stan K9IUQ





W8JI2007-02-24
RE: Benchmarks
by N0AH on February 23, 2007 So Alan or Tom,

How do hybred couplers apply to this article? They seem like a perfect solution- Or are we using smoke and mirrors. >>

For what? Matching?

They have a place in the world but it is generally not in high power antenna systems.

I use them to split signal between receivers because power is almost free at receive levels. I don't care about loss. I'd almost never use them in a transmitting antenna.

73 Tom
Reply to a comment by : N0AH on 2007-02-23

So Alan or Tom, How do hybred couplers apply to this article? They seem like a perfect solution- Or are we using smoke and mirrors.
W8JI2007-02-24
RE: Benchmarks
by W4LGH on February 23, 2007 Well W8JI...I guess the laugh is on you. That quote was a quote taken from whatis.com on what the SKIN EFFECT is.>>

No, the laugh is on anone who swallows such obvious rubbish from a web site that goes around extracting misinformation from other non-peer reviewed websites.

Education now has shifted towards quoting nonsense offered on Internet instead of being based on direct experience, peer-reviewed textbooks, and old fashoned common sense.

Any reference that claims a conductor has reduced skin effect or skin effect based loss through use of twisted or stranded wire is seriously out of touch with the real world.

This includes whatis.com

<<Was not my quote, and I had it in quote marks. So I guess you are smarter than all the researchers out there. Thats good, cuz we need more smart people in radio!>>

Well, I certainly have no doubt whoever wrote that golden nugget you quoted doesn't understand behavior of conductors at radio frequencies. Anyone with half a brain who looks at lightning protection systems, transmission lines, tank circuits, and inductors can clearly see low loss high frequency systems employ smooth surface conductors for lowest loss for a given conductor size.

Anyone who understands the reason skin effect exists would know stranding only makes the issue worse, not better.

<<Remember you have to DIP the Plate to resonance get maximum energy transfer..! >>

Not necessarily. That's only true with a reasonably low loss tank, stable element voltages, no anode to input feedback, and a PA tube that conducts less than 360 degrees.

The only certain way to tune for maximum energy transfer in all cases is to tune for maximum energy transfer, and when it is peaked in one direction it does NOT mean the system is bilaterally tuned (matched in the reverse direction).

You can try this yourself with an antenna tuner. Tune the tuner into a perfect 50 ohm load. Note the 50 ohm SWR on the exciter. Now reverse the connections on the tuner. You will see, if the tuner has noticeable loss, it is NOT tuned the same in the reverse direction.

As a matter of fact tuner efficiency could be determined by analyzing the SWR error when the tuner is reversed.

Another example is coaxial cable. A cable short in terms of wavelength on lower frequencies has less loss when mismatched in a direction that reduces current levels.

Lossy systems are not always bilateral.

The real world is where the rubber meets the road and common sense takes over. Parroting books (or whatis.com) without a feel for the REAL behavior and the reasons behind it will often get us in trouble.

73 Tom
Reply to a comment by : W4LGH on 2007-02-23

Well W8JI...I guess the laugh is on you. That quote was a quote taken from whatis.com on what the SKIN EFFECT is. Was not my quote, and I had it in quote marks. So I guess you are smarter than all the researchers out there. Thats good, cuz we need more smart people in radio! Remember you have to DIP the Plate to resonance get get maximun energy transfer..!
Reply to a comment by : W8JI on 2007-02-23

"Capture area" really has little to do with physical size of the antenna. It relates solidly only to frequency and gain. The somewhat questionable exception is in an aperture antenna like a horn or parabolic reflector antenna. Even in these special aperture based antennas the effective aperture differs significantly from actual aperture, ranging from 45% to 75% with 65% being considered a very good design. If I have two exactly identical antennas in every way except I make one from a more lossy material, the lossy antenna will have less "capture area". Effective aperture is nothing more than a way we can correct for the change in wavelength and gain of antennas. If I have two antennas 500 feet apart, they are twice as far apart in terms of the wavelength as frequency is doubled. Capture area must be a Ham term. All that aside, it is virtually meaningless for determining how good an antenna is for receiving. Once the system limits on external noise concerns about absolute power or effective aperture are pointless. The only thing that matters is the ratio of desired signal to undesired signal received, and that has nothing to do with effective aperture or gain. It is all about pattern shape, not pattern size.
Reply to a comment by : KY1V on 2007-02-23

>RE: Benchmarks Reply by KY1V on February 23, 2007 Mail this to a friend! Yeah, that's how I want to spend my weekends, picking through garbage for antenna wire... Good Grief! David ~ KY1V< ::I plan to spend my retirement dumpster diving, because I didn't get much of this earlier. :-) WB2WIK/6 ------------------------ Maybe you can find a hardly used CapcitiveReciprocityMicroHomeBrewCoaxialDynamic Antenna wire in one of those and talk to me in Jamaica! I think I can hear you on your dummy load! David ~ KY1V
Reply to a comment by : WB2WIK on 2007-02-23

>RE: Benchmarks Reply by KY1V on February 23, 2007 Mail this to a friend! Yeah, that's how I want to spend my weekends, picking through garbage for antenna wire... Good Grief! David ~ KY1V< ::I plan to spend my retirement dumpster diving, because I didn't get much of this earlier. :-) WB2WIK/6
Reply to a comment by : KY1V on 2007-02-23

Yeah, that's how I want to spend my weekends, picking through garbage for antenna wire... Good Grief! David ~ KY1V
Reply to a comment by : N0AH on 2007-02-23

I say plug in coax to radio. Then feed coax to antenna. Check for any potetial problems. Have fun...bench that-
K4VVX2007-02-24
RE: Benchmarks
Forgot something-

"What a term or phrase means to me is not necessarily the same thing that it means to you"

This is due to the way we learned it and remembered it and geographical, regional and coloqial use.

Carl
Reply to a comment by : K4VVX on 2007-02-24

Wow, This has certainly been an interesting thread. I find that it is always informative to hear several intelligent and knowledgeable people discuss the "facts". A casual bystander who has no emotional axe to grind can learn a lot by reading this sort of thing. "Benchmarks" are something that we use and create every day. Every time that we perform an experiment, or take a measurement, we create a "Benchmark". It doesn't have to be tracable to NIST or even written down. It is still a "Benchmark" as in, "I can readily see that I turned that pot in the wrong direction". Our mental "Benchmark" told us to expect an increase, but our reading decreased. Our "Benchmark" in this case was created years ago when we took a similar measurement. We knew what to expect. This thread could have been about 1/3 the length that it is by the non-use of "interchangable" terms that are not really "interchangable" (Personal decision most of the time) Examples are: 1. "Antennas" versus "Antenna Systems" 2. "Reciprocity" versus "Perceived Reciprocity" 3. "Tuners" versus "Couplers" 4. "Antenna Tuning" versus "Impedance Matching" Very interesting and thought provoking article, Alan. Thank you for posting it. I don't think that there is a single person who didn't learn SOMETHING from it. It only resulted in a couple of personal attacks or flames and most of them were rightfully ignored. Thanks again, Alan. Bravo Zulu - Well Done. You made everybody THINK, and that is something that we all need to do more of. 73, Carl....k4vvx
Reply to a comment by : W7ETA on 2007-02-23

W2DU's book is on line. Heard a rumor that the reason why the universe's density varies is because the BIG BANG had more than one frequency. Resonant frequencies, with in the universe, were amplified, like sound waves in a tube. 73 Bob
Reply to a comment by : N0AH on 2007-02-23

Dave, KY1V and you are giving me a hard time about my call sign. Those who really know me tend to focus on the AH. So lets just keep the issues about our call signs separate- And thanks for the congrads on my extra ticket. I got that kind when I took a 20WPM CW test, written exam,you know.....those days. Now I just sit here and read all the BS on Eham by the multitude of pig farmers in Georgia. I have to admit, this Bench Mark thread has really hit the nerve of the puriest in the hobby. I don't think they are sleeping all that well. I worked some code this afternoon. I hit the keyer, the signal went to the antenna, then I heard the signal from the other station in my speaker- wow-
K4VVX2007-02-24
RE: Benchmarks
Wow, This has certainly been an interesting thread. I find that it is always informative to hear several intelligent and knowledgeable people discuss the "facts". A casual bystander who has no emotional axe to grind can learn a lot by reading this sort of thing. "Benchmarks" are something that we use and create every day. Every time that we perform an experiment, or take a measurement, we create a "Benchmark". It doesn't have to be tracable to NIST or even written down. It is still a "Benchmark" as in, "I can readily see that I turned that pot in the wrong direction". Our mental "Benchmark" told us to expect an increase, but our reading decreased. Our "Benchmark" in this case was created years ago when we took a similar measurement. We knew what to expect.

This thread could have been about 1/3 the length that it is by the non-use of "interchangable" terms that are not really "interchangable" (Personal decision most of the time) Examples are:

1. "Antennas" versus "Antenna Systems"
2. "Reciprocity" versus "Perceived Reciprocity"
3. "Tuners" versus "Couplers"
4. "Antenna Tuning" versus "Impedance Matching"

Very interesting and thought provoking article, Alan. Thank you for posting it. I don't think that there is a single person who didn't learn SOMETHING from it. It only resulted in a couple of personal attacks or flames and most of them were rightfully ignored.

Thanks again, Alan. Bravo Zulu - Well Done. You made everybody THINK, and that is something that we all need to do more of.

73, Carl....k4vvx
Reply to a comment by : W7ETA on 2007-02-23

W2DU's book is on line. Heard a rumor that the reason why the universe's density varies is because the BIG BANG had more than one frequency. Resonant frequencies, with in the universe, were amplified, like sound waves in a tube. 73 Bob
Reply to a comment by : N0AH on 2007-02-23

Dave, KY1V and you are giving me a hard time about my call sign. Those who really know me tend to focus on the AH. So lets just keep the issues about our call signs separate- And thanks for the congrads on my extra ticket. I got that kind when I took a 20WPM CW test, written exam,you know.....those days. Now I just sit here and read all the BS on Eham by the multitude of pig farmers in Georgia. I have to admit, this Bench Mark thread has really hit the nerve of the puriest in the hobby. I don't think they are sleeping all that well. I worked some code this afternoon. I hit the keyer, the signal went to the antenna, then I heard the signal from the other station in my speaker- wow-
W7ETA2007-02-23
RE: Benchmarks
W2DU's book is on line.

Heard a rumor that the reason why the universe's density varies is because the BIG BANG had more than one frequency. Resonant frequencies, with in the universe, were amplified, like sound waves in a tube.

73
Bob
Reply to a comment by : N0AH on 2007-02-23

Dave, KY1V and you are giving me a hard time about my call sign. Those who really know me tend to focus on the AH. So lets just keep the issues about our call signs separate- And thanks for the congrads on my extra ticket. I got that kind when I took a 20WPM CW test, written exam,you know.....those days. Now I just sit here and read all the BS on Eham by the multitude of pig farmers in Georgia. I have to admit, this Bench Mark thread has really hit the nerve of the puriest in the hobby. I don't think they are sleeping all that well. I worked some code this afternoon. I hit the keyer, the signal went to the antenna, then I heard the signal from the other station in my speaker- wow-
N0AH2007-02-23
Benchmarks
So Alan or Tom,

How do hybred couplers apply to this article? They seem like a perfect solution- Or are we using smoke and mirrors.
N0AH2007-02-23
Benchmarks
KY1V:

Your 6Y log is pointless.

This is my two cents. The chances of your angle of radiation going out at the same angle of radiation coming in is slight. Maybe close, but not exact. Why do you think lower yagi's on a stacked tower hear DX in the early morning better than the higher yagi's above.

I guess we could all get Moon-Raker 4's to solve the issue.
N0AH2007-02-23
Benchmarks
W4LGH:

While Tom, W8JI can sometimes have poor ham shack manners, he is most likely this country's leading expert on low band HF antennas.

As a researcher, I would be very learly of information from a web-sites, especially third party quotes. So you might want to expand your internet research.

I'm not saying you are right and he is wrong, but W8JI is an expert. A few years ago, I listened to him work at his grayline on 160M JT1CO. That was not luck- That was skill.
N0AH2007-02-23
Benchmarks
Dave,

KY1V and you are giving me a hard time about my call sign. Those who really know me tend to focus on the AH. So lets just keep the issues about our call signs separate-

And thanks for the congrads on my extra ticket. I got that kind when I took a 20WPM CW test, written exam,you know.....those days.

Now I just sit here and read all the BS on Eham by the multitude of pig farmers in Georgia.

I have to admit, this Bench Mark thread has really hit the nerve of the puriest in the hobby. I don't think they are sleeping all that well.

I worked some code this afternoon. I hit the keyer, the signal went to the antenna, then I heard the signal from the other station in my speaker- wow-
KA0GKT2007-02-23
RE: Benchmarks
Alex wrote:

"This site is such a waste of a resource that could be very valuable if the people who control this site would get off their asses and monitor it. This thread contains SOME excellent information but the MAJORITY of stuff posted is BS. The people who could learn the most don't know what is and what isn't BS so it all becomes worthless. Too bad! "


Alex....

===============


I wouldn't necessarily say it is a waste of resource if the discussion enlightens and the falacies are laid to rest.

So, you have stated that some of the information is excellent, but most is BS. Enlighten us. Help to filter the wheat from the chaff, the diamonds from the Bull.

The ball's now in your court. Prove to us that your statement isn't just another load of BS in this thread...Don't get me wrong, I don't necessarily disagree with your assessment of the validity of many of the RF wives tales which seem to rear their ugly heads whenever antennas are discussed, however I'm interested in hearing your assessment of what is BS and what isn't. Also include an indication of your curriculum vitae on the subject.

73 DE KAØGKT/7

--Steve
Reply to a comment by : SSB on 2007-02-23

This site is such a waste of a resource that could be very valuable if the people who control this site would get off their asses and monitor it. This thread contains SOME excellent information but the MAJORITY of stuff posted is BS. The people who could learn the most don't know what is and what isn't BS so it all becomes worthless. Too bad! Alex....
N3OX2007-02-23
RE: Benchmarks
"So I guess you are smarter than all the researchers out there. Thats good, cuz we need more smart people in radio! "

All the research on skin effect has been published on whatis.com in a concise half-page article! That's certainly a definitive reference if I've ever seen one.

You learn something new every day.

Dan
Reply to a comment by : N3OX on 2007-02-23

"I think I can hear you on your dummy load! David ~ KY1V" I think I can hear 6Y1V on a dummy load ;-) Must be my effective aperature.
Reply to a comment by : W8JI on 2007-02-23

"Capture area" really has little to do with physical size of the antenna. It relates solidly only to frequency and gain. The somewhat questionable exception is in an aperture antenna like a horn or parabolic reflector antenna. Even in these special aperture based antennas the effective aperture differs significantly from actual aperture, ranging from 45% to 75% with 65% being considered a very good design. If I have two exactly identical antennas in every way except I make one from a more lossy material, the lossy antenna will have less "capture area". Effective aperture is nothing more than a way we can correct for the change in wavelength and gain of antennas. If I have two antennas 500 feet apart, they are twice as far apart in terms of the wavelength as frequency is doubled. Capture area must be a Ham term. All that aside, it is virtually meaningless for determining how good an antenna is for receiving. Once the system limits on external noise concerns about absolute power or effective aperture are pointless. The only thing that matters is the ratio of desired signal to undesired signal received, and that has nothing to do with effective aperture or gain. It is all about pattern shape, not pattern size.
Reply to a comment by : KY1V on 2007-02-23

>RE: Benchmarks Reply by KY1V on February 23, 2007 Mail this to a friend! Yeah, that's how I want to spend my weekends, picking through garbage for antenna wire... Good Grief! David ~ KY1V< ::I plan to spend my retirement dumpster diving, because I didn't get much of this earlier. :-) WB2WIK/6 ------------------------ Maybe you can find a hardly used CapcitiveReciprocityMicroHomeBrewCoaxialDynamic Antenna wire in one of those and talk to me in Jamaica! I think I can hear you on your dummy load! David ~ KY1V
Reply to a comment by : WB2WIK on 2007-02-23

>RE: Benchmarks Reply by KY1V on February 23, 2007 Mail this to a friend! Yeah, that's how I want to spend my weekends, picking through garbage for antenna wire... Good Grief! David ~ KY1V< ::I plan to spend my retirement dumpster diving, because I didn't get much of this earlier. :-) WB2WIK/6
Reply to a comment by : KY1V on 2007-02-23

Yeah, that's how I want to spend my weekends, picking through garbage for antenna wire... Good Grief! David ~ KY1V
Reply to a comment by : N0AH on 2007-02-23

I say plug in coax to radio. Then feed coax to antenna. Check for any potetial problems. Have fun...bench that-
KY1V2007-02-23
RE: Benchmarks

W8JI Wrote:


"All that aside, it is virtually meaningless for determining how good an antenna is for receiving. Once the system limits on external noise concerns about absolute power or effective aperture are pointless. The only thing that matters is the ratio of desired signal to undesired signal received, and that has nothing to do with effective aperture or gain. It is all about pattern shape, not pattern size."

...and I concur...

http://www.6y1v.com/station.htm

Check out the pattern shape on these bad boys. Read em weep boys.

David ~ KY1V


PS: I better quit clowing around in here...this topic is getting heated! My dialetric is melting!

Reply to a comment by : W8JI on 2007-02-23

"Capture area" really has little to do with physical size of the antenna. It relates solidly only to frequency and gain. The somewhat questionable exception is in an aperture antenna like a horn or parabolic reflector antenna. Even in these special aperture based antennas the effective aperture differs significantly from actual aperture, ranging from 45% to 75% with 65% being considered a very good design. If I have two exactly identical antennas in every way except I make one from a more lossy material, the lossy antenna will have less "capture area". Effective aperture is nothing more than a way we can correct for the change in wavelength and gain of antennas. If I have two antennas 500 feet apart, they are twice as far apart in terms of the wavelength as frequency is doubled. Capture area must be a Ham term. All that aside, it is virtually meaningless for determining how good an antenna is for receiving. Once the system limits on external noise concerns about absolute power or effective aperture are pointless. The only thing that matters is the ratio of desired signal to undesired signal received, and that has nothing to do with effective aperture or gain. It is all about pattern shape, not pattern size.
Reply to a comment by : KY1V on 2007-02-23

>RE: Benchmarks Reply by KY1V on February 23, 2007 Mail this to a friend! Yeah, that's how I want to spend my weekends, picking through garbage for antenna wire... Good Grief! David ~ KY1V< ::I plan to spend my retirement dumpster diving, because I didn't get much of this earlier. :-) WB2WIK/6 ------------------------ Maybe you can find a hardly used CapcitiveReciprocityMicroHomeBrewCoaxialDynamic Antenna wire in one of those and talk to me in Jamaica! I think I can hear you on your dummy load! David ~ KY1V
Reply to a comment by : WB2WIK on 2007-02-23

>RE: Benchmarks Reply by KY1V on February 23, 2007 Mail this to a friend! Yeah, that's how I want to spend my weekends, picking through garbage for antenna wire... Good Grief! David ~ KY1V< ::I plan to spend my retirement dumpster diving, because I didn't get much of this earlier. :-) WB2WIK/6
Reply to a comment by : KY1V on 2007-02-23

Yeah, that's how I want to spend my weekends, picking through garbage for antenna wire... Good Grief! David ~ KY1V
Reply to a comment by : N0AH on 2007-02-23

I say plug in coax to radio. Then feed coax to antenna. Check for any potetial problems. Have fun...bench that-
N3OX2007-02-23
RE: Benchmarks
"I think I can hear you on your dummy load!

David ~ KY1V"

I think I can hear 6Y1V on a dummy load ;-)

Must be my effective aperature.
Reply to a comment by : W8JI on 2007-02-23

"Capture area" really has little to do with physical size of the antenna. It relates solidly only to frequency and gain. The somewhat questionable exception is in an aperture antenna like a horn or parabolic reflector antenna. Even in these special aperture based antennas the effective aperture differs significantly from actual aperture, ranging from 45% to 75% with 65% being considered a very good design. If I have two exactly identical antennas in every way except I make one from a more lossy material, the lossy antenna will have less "capture area". Effective aperture is nothing more than a way we can correct for the change in wavelength and gain of antennas. If I have two antennas 500 feet apart, they are twice as far apart in terms of the wavelength as frequency is doubled. Capture area must be a Ham term. All that aside, it is virtually meaningless for determining how good an antenna is for receiving. Once the system limits on external noise concerns about absolute power or effective aperture are pointless. The only thing that matters is the ratio of desired signal to undesired signal received, and that has nothing to do with effective aperture or gain. It is all about pattern shape, not pattern size.
Reply to a comment by : KY1V on 2007-02-23

>RE: Benchmarks Reply by KY1V on February 23, 2007 Mail this to a friend! Yeah, that's how I want to spend my weekends, picking through garbage for antenna wire... Good Grief! David ~ KY1V< ::I plan to spend my retirement dumpster diving, because I didn't get much of this earlier. :-) WB2WIK/6 ------------------------ Maybe you can find a hardly used CapcitiveReciprocityMicroHomeBrewCoaxialDynamic Antenna wire in one of those and talk to me in Jamaica! I think I can hear you on your dummy load! David ~ KY1V
Reply to a comment by : WB2WIK on 2007-02-23

>RE: Benchmarks Reply by KY1V on February 23, 2007 Mail this to a friend! Yeah, that's how I want to spend my weekends, picking through garbage for antenna wire... Good Grief! David ~ KY1V< ::I plan to spend my retirement dumpster diving, because I didn't get much of this earlier. :-) WB2WIK/6
Reply to a comment by : KY1V on 2007-02-23

Yeah, that's how I want to spend my weekends, picking through garbage for antenna wire... Good Grief! David ~ KY1V
Reply to a comment by : N0AH on 2007-02-23

I say plug in coax to radio. Then feed coax to antenna. Check for any potetial problems. Have fun...bench that-
W4LGH2007-02-23
RE: Benchmarks
Well W8JI...I guess the laugh is on you. That quote was a quote taken from whatis.com on what the SKIN EFFECT is. Was not my quote, and I had it in quote marks. So I guess you are smarter than all the researchers out there. Thats good, cuz we need more smart people in radio!

Remember you have to DIP the Plate to resonance get get maximun energy transfer..!

Reply to a comment by : W8JI on 2007-02-23

"Capture area" really has little to do with physical size of the antenna. It relates solidly only to frequency and gain. The somewhat questionable exception is in an aperture antenna like a horn or parabolic reflector antenna. Even in these special aperture based antennas the effective aperture differs significantly from actual aperture, ranging from 45% to 75% with 65% being considered a very good design. If I have two exactly identical antennas in every way except I make one from a more lossy material, the lossy antenna will have less "capture area". Effective aperture is nothing more than a way we can correct for the change in wavelength and gain of antennas. If I have two antennas 500 feet apart, they are twice as far apart in terms of the wavelength as frequency is doubled. Capture area must be a Ham term. All that aside, it is virtually meaningless for determining how good an antenna is for receiving. Once the system limits on external noise concerns about absolute power or effective aperture are pointless. The only thing that matters is the ratio of desired signal to undesired signal received, and that has nothing to do with effective aperture or gain. It is all about pattern shape, not pattern size.
Reply to a comment by : KY1V on 2007-02-23

>RE: Benchmarks Reply by KY1V on February 23, 2007 Mail this to a friend! Yeah, that's how I want to spend my weekends, picking through garbage for antenna wire... Good Grief! David ~ KY1V< ::I plan to spend my retirement dumpster diving, because I didn't get much of this earlier. :-) WB2WIK/6 ------------------------ Maybe you can find a hardly used CapcitiveReciprocityMicroHomeBrewCoaxialDynamic Antenna wire in one of those and talk to me in Jamaica! I think I can hear you on your dummy load! David ~ KY1V
Reply to a comment by : WB2WIK on 2007-02-23

>RE: Benchmarks Reply by KY1V on February 23, 2007 Mail this to a friend! Yeah, that's how I want to spend my weekends, picking through garbage for antenna wire... Good Grief! David ~ KY1V< ::I plan to spend my retirement dumpster diving, because I didn't get much of this earlier. :-) WB2WIK/6
Reply to a comment by : KY1V on 2007-02-23

Yeah, that's how I want to spend my weekends, picking through garbage for antenna wire... Good Grief! David ~ KY1V
Reply to a comment by : N0AH on 2007-02-23

I say plug in coax to radio. Then feed coax to antenna. Check for any potetial problems. Have fun...bench that-
W8JI2007-02-23
RE: Benchmarks
"Capture area" really has little to do with physical size of the antenna. It relates solidly only to frequency and gain.

The somewhat questionable exception is in an aperture antenna like a horn or parabolic reflector antenna. Even in these special aperture based antennas the effective aperture differs significantly from actual aperture, ranging from 45% to 75% with 65% being considered a very good design.

If I have two exactly identical antennas in every way except I make one from a more lossy material, the lossy antenna will have less "capture area".

Effective aperture is nothing more than a way we can correct for the change in wavelength and gain of antennas. If I have two antennas 500 feet apart, they are twice as far apart in terms of the wavelength as frequency is doubled.

Capture area must be a Ham term.

All that aside, it is virtually meaningless for determining how good an antenna is for receiving. Once the system limits on external noise concerns about absolute power or effective aperture are pointless. The only thing that matters is the ratio of desired signal to undesired signal received, and that has nothing to do with effective aperture or gain. It is all about pattern shape, not pattern size.
Reply to a comment by : KY1V on 2007-02-23

>RE: Benchmarks Reply by KY1V on February 23, 2007 Mail this to a friend! Yeah, that's how I want to spend my weekends, picking through garbage for antenna wire... Good Grief! David ~ KY1V< ::I plan to spend my retirement dumpster diving, because I didn't get much of this earlier. :-) WB2WIK/6 ------------------------ Maybe you can find a hardly used CapcitiveReciprocityMicroHomeBrewCoaxialDynamic Antenna wire in one of those and talk to me in Jamaica! I think I can hear you on your dummy load! David ~ KY1V
Reply to a comment by : WB2WIK on 2007-02-23

>RE: Benchmarks Reply by KY1V on February 23, 2007 Mail this to a friend! Yeah, that's how I want to spend my weekends, picking through garbage for antenna wire... Good Grief! David ~ KY1V< ::I plan to spend my retirement dumpster diving, because I didn't get much of this earlier. :-) WB2WIK/6
Reply to a comment by : KY1V on 2007-02-23

Yeah, that's how I want to spend my weekends, picking through garbage for antenna wire... Good Grief! David ~ KY1V
Reply to a comment by : N0AH on 2007-02-23

I say plug in coax to radio. Then feed coax to antenna. Check for any potetial problems. Have fun...bench that-
N4SL2007-02-23
RE: Benchmarks
Come on, let's get back to more interesting subjects like Flux Capacitors and Fan Dipoles.
Reply to a comment by : W8JI on 2007-02-23

by W4LGH on February 23, 2007 Seems we don't understand "Skin Effect" either.>> That's correct. It certainly seems some of us don't understand skin effect. Let me show why. You wrote: .Here's a deffination... skin effect Skin effect is a tendency for alternating current (AC) to flow mostly near the outer surface of a solid electrical conductor, such as metal wire, at frequencies above the audio range. The effect becomes more and more apparent as the frequency increases. The main problem with skin effect is that it increases the effective resistance of a wire for AC at moderate to high frequencies, compared with the resistance of the same wire at direct current (DC) and low AC frequencies. The effect is most pronounced in radio-frequency (RF) systems, especially antennas and transmission lines. But it can also affect the performance of high-fidelity sound equipment by causing attenuation in the treble range (the highest-pitched components of the audio).>> Anyone who understands skin effect would fall out of their chairs laughing at the last part of that quote. Very few people have 20 mile long 5" diameter low impedance speaker leads. In order for skin depth to have an effect on losses, the wire has to be very thick in terms of skin depth. It also has to be very long in proportion. That quote reads like something from an Audio-phoole page. Then it goes on to make this priceless misstatement of fact: <<Skin effect can be reduced by using stranded rather than solid wire. This increases the effective surface area of the wire for a given wire gauge. >> That's pure 100% bull. Skin depth is cause by flux density. The very center of a conductor is surrounded by more magnetic flux than the outside edges. This causes the center areas to have higher impedance than the outer areas. Stranded or smooth, the flux density at the center is the same for the same diameter and the same current. Current is still forced to the outer edges. The only difference is stranded wire has air gaps at the outer edge and has HIGHER resistance....NOT lower. If you doubt what I say and you believe the web page you extracted that priceless brown bull-nugget from, then just apply a little logic. At high frequencies where skin depth is most important, transmission lines use smooth surface conductors. They use smooth foil shields against the dielectric, and smooth center conductors. The lowest loss cables for a given size ALWAYS have smooth conductors, not woven or stranded. The same is true for leads in tank circuits. High Q tanks always use smooth conductors and low loss tank leads are always smooth ribbon. As a matter of fact a #14 solid buss wire has about the same loss per unit length as a #10 finely stranded wire and a 3/8" woven braid at 30MHz! If you have relay with properly sized leads to the armature at DC where the contact bars and leads heat evenly, the finely stranded flexible leads will melt long before the smooth bar heats at high frequencies!! Whoever wrote that page you are quoting hasn't a clue what they are talking about. As frequency and power increases we all know there is a huge push towards use of wide smooth conductors. This is because of skin effect. As a matter of fact stranded and solid wires are equal for a given conductor cross section only at DC. As frequency increases the stranded wire has a faster increase in resistance than the solid wire. This is because as skin effect forces current out onto outer strands, the air gap between outer edges of the strand actually reduces effective cross section carrying current. This is why HF tank coils use smooth conductor surface areas, why lightning protection conductors are much more effective when smooth, why transmission lines with lowest loss at high frequencies have smooth conductor surfaces on the inside of the shield and the outside of the center. These audio phools are ruining basic core understaning of electrical circuits with their audiophool nonsense! 73 Tom
Reply to a comment by : W4LGH on 2007-02-23

Seems we don't understand "Skin Effect" either..ok... Here's a deffination... skin effect Skin effect is a tendency for alternating current (AC) to flow mostly near the outer surface of a solid electrical conductor, such as metal wire, at frequencies above the audio range. The effect becomes more and more apparent as the frequency increases. The main problem with skin effect is that it increases the effective resistance of a wire for AC at moderate to high frequencies, compared with the resistance of the same wire at direct current (DC) and low AC frequencies. The effect is most pronounced in radio-frequency (RF) systems, especially antennas and transmission lines. But it can also affect the performance of high-fidelity sound equipment by causing attenuation in the treble range (the highest-pitched components of the audio). Skin effect can be reduced by using stranded rather than solid wire. This increases the effective surface area of the wire for a given wire gauge. Tinned wire should be avoided because tin has higher resistance than copper. In large RF antenna arrays, hollow tubing can be used in place of solid rods with little or no loss of efficiency; in this respect, skin effect is an asset. It also works in favor of the use of copper-clad steel wire for more modest antennas. Such wire is mechanically stronger than solid or stranded copper, because steel has a higher tensile strength than copper. The skin effect causes most of the current to flow through the copper cladding, which is a better electrical conductor than steel. -------- AA4PB wrote.. ~As long as you can match that impedance to the feed line you can transfer power into the antenna. If you can transfer power into an antenna then most of it (less the small I*R loss in the resistance of the wire) will be radiated. --------- What you say here holds some truth, if the non-resoanant antenna is not far off resonance. Case in point, you can load a 10penny nail up on 80 meters by matching its impedance, but I do NOT think you will radiate much power! --------- If you truely believe that the ends of an antenna are open at all times then what develops the standing waves on a non-resonant antenna. I submit that the ends look more electrically shorted thus reflecting the normally radiated energy back down the antenna. This reflected power also create changes at the feedpoint impedance. ---------- I liked the post about antennas and antenna systems. LIke I have been saying there is something being lost in the translation here. There is NOT a professional broadcaster out there using a non-resonant antenna, unless it is part or a multi-antenna system and it is being used out of phase to decouple other parts of the antenna. Stirba curtains/rombics & Beverages are all multi-antennas used to make up a single antenna system. The antenna system is resonant, even tho it is made up of both resonant and non-resonant elements. Here is another great link... http://www.radio-electronics.com/info/antennas/basics/resonance.php 73 de W4LGH - Alan http://www.w4lgh.com
Reply to a comment by : N1XBP on 2007-02-23

Sometimes I think eHam is a lost cause. I think this thread devolved after a bit of debate about receive/transmit performance not being equal on an antenna. Then someone misunderstood that as being false because of reciprocity of pattern and gain. Those are two seperate issues. If antennas transmit just as well as they receive, why don't we all transmit into beverages? Yes, reciprocity holds true for the pattern and gain, except in the real world the ground losses cause it to be a lousy transmit antenna. See the conceptual difference now? As for antenna resonance, there are circles being gone through here. The antenna and the antenna system are not exactly one in the same. I can have a resonant antenna system with a non resonant antenna element. Then, some people seem to think that you can't feed a non resonant antenna without a tuner. Not true if you pick a feed point that has the impedance you want for the frequency you intend to use. What your pattern will look like is another story. And last, 1:1 SWR isn't entirely related to resonance, since impedance is a complex number and a high non reactive componant will lower the SWR by lowering the Q of the tuned circuit the antenna system represents and burning up more of the power that would have been reflected as heat.
Reply to a comment by : AA4PB on 2007-02-23

Alan, I submit that the ends of a dipole (resonant or not) are ALWAYS open and ALWAYS high impedance. That is exactly what makes the feed impedance of a dipole change as you change its physical length. When each side of a dipole is an exact odd multiple of 1/4 wavelength long then the standing wave on the antenna transforms the high impedance at the end to a fairly low impedance at the center. If the antenna is some other (non-resonant) length then the standing wave transforms the high impedance at the end to some other impedance at the center. As long as you can match that impedance to the feed line you can transfer power into the antenna. If you can transfer power into an antenna then most of it (less the small I*R loss in the resistance of the wire) will be radiated. An antenna has basically two ways to get rid of the power that gets applied to it. Either is is radiated or it is turned to heat. The only thing that can turn it to heat is the resistance of the wire. Since the resistance of the wire in a typical doublet antenna is very low, most of the power must be radiated. Making an antenna a non-resonant length does not change the resistance of the wire therefore it doesn't raise the amount of power disipated as heat by any significant amount.
Reply to a comment by : AD4U on 2007-02-23

Doing something to add 1 or 2 dB to your signal may not make much difference by itself. However if you have the $$ and the time and the expertise, making changes that add a dB here and a dB there and another dB somewhere else, collectively WILL make a noticeable difference. This is often what separates the BIG GUNS from the little pistols.
W8JI2007-02-23
RE: Benchmarks
by W4LGH on February 23, 2007 Seems we don't understand "Skin Effect" either.>>

That's correct. It certainly seems some of us don't understand skin effect. Let me show why.


You wrote:
.Here's a deffination...
skin effect

Skin effect is a tendency for alternating current (AC) to flow mostly near the outer surface of
a solid electrical conductor, such as metal wire, at frequencies above the audio range. The effect
becomes more and more apparent as the frequency increases.
The main problem with skin effect is that it increases the effective resistance of a wire for AC
at moderate to high frequencies, compared with the resistance of the same wire at direct current (DC)
and low AC frequencies. The effect is most pronounced in radio-frequency (RF) systems, especially
antennas and transmission lines. But it can also affect the performance of high-fidelity sound
equipment by causing attenuation in the treble range (the highest-pitched components of the audio).>>

Anyone who understands skin effect would fall out of their chairs laughing at the last part of that quote. Very few people have 20 mile long 5" diameter low impedance speaker leads.

In order for skin depth to have an effect on losses, the wire has to be very thick in terms of skin depth. It also has to be very long in proportion.

That quote reads like something from an Audio-phoole page.

Then it goes on to make this priceless misstatement of fact:

<<Skin effect can be reduced by using stranded rather than solid wire. This increases the effective
surface area of the wire for a given wire gauge. >>

That's pure 100% bull. Skin depth is cause by flux density. The very center of a conductor is surrounded by more magnetic flux than the outside edges. This causes the center areas to have higher impedance than the outer areas.

Stranded or smooth, the flux density at the center is the same for the same diameter and the same current. Current is still forced to the outer edges. The only difference is stranded wire has air gaps at the outer edge and has HIGHER resistance....NOT lower.

If you doubt what I say and you believe the web page you extracted that priceless brown bull-nugget from, then just apply a little logic.

At high frequencies where skin depth is most important, transmission lines use smooth surface conductors. They use smooth foil shields against the dielectric, and smooth center conductors. The lowest loss cables for a given size ALWAYS have smooth conductors, not woven or stranded.

The same is true for leads in tank circuits. High Q tanks always use smooth conductors and low loss tank leads are always smooth ribbon. As a matter of fact a #14 solid buss wire has about the same loss per unit length as a #10 finely stranded wire and a 3/8" woven braid at 30MHz!

If you have relay with properly sized leads to the armature at DC where the contact bars and leads heat evenly, the finely stranded flexible leads will melt long before the smooth bar heats at high frequencies!!

Whoever wrote that page you are quoting hasn't a clue what they are talking about.

As frequency and power increases we all know there is a huge push towards use of wide smooth conductors. This is because of skin effect.

As a matter of fact stranded and solid wires are equal for a given conductor cross section only at DC. As frequency increases the stranded wire has a faster increase in resistance than the solid wire. This is because as skin effect forces current out onto outer strands, the air gap between outer edges of the strand actually reduces effective cross section carrying current.

This is why HF tank coils use smooth conductor surface areas, why lightning protection conductors are much more effective when smooth, why transmission lines with lowest loss at high frequencies have smooth conductor surfaces on the inside of the shield and the outside of the center.

These audio phools are ruining basic core understaning of electrical circuits with their audiophool nonsense!

73 Tom
Reply to a comment by : W4LGH on 2007-02-23

Seems we don't understand "Skin Effect" either..ok... Here's a deffination... skin effect Skin effect is a tendency for alternating current (AC) to flow mostly near the outer surface of a solid electrical conductor, such as metal wire, at frequencies above the audio range. The effect becomes more and more apparent as the frequency increases. The main problem with skin effect is that it increases the effective resistance of a wire for AC at moderate to high frequencies, compared with the resistance of the same wire at direct current (DC) and low AC frequencies. The effect is most pronounced in radio-frequency (RF) systems, especially antennas and transmission lines. But it can also affect the performance of high-fidelity sound equipment by causing attenuation in the treble range (the highest-pitched components of the audio). Skin effect can be reduced by using stranded rather than solid wire. This increases the effective surface area of the wire for a given wire gauge. Tinned wire should be avoided because tin has higher resistance than copper. In large RF antenna arrays, hollow tubing can be used in place of solid rods with little or no loss of efficiency; in this respect, skin effect is an asset. It also works in favor of the use of copper-clad steel wire for more modest antennas. Such wire is mechanically stronger than solid or stranded copper, because steel has a higher tensile strength than copper. The skin effect causes most of the current to flow through the copper cladding, which is a better electrical conductor than steel. -------- AA4PB wrote.. ~As long as you can match that impedance to the feed line you can transfer power into the antenna. If you can transfer power into an antenna then most of it (less the small I*R loss in the resistance of the wire) will be radiated. --------- What you say here holds some truth, if the non-resoanant antenna is not far off resonance. Case in point, you can load a 10penny nail up on 80 meters by matching its impedance, but I do NOT think you will radiate much power! --------- If you truely believe that the ends of an antenna are open at all times then what develops the standing waves on a non-resonant antenna. I submit that the ends look more electrically shorted thus reflecting the normally radiated energy back down the antenna. This reflected power also create changes at the feedpoint impedance. ---------- I liked the post about antennas and antenna systems. LIke I have been saying there is something being lost in the translation here. There is NOT a professional broadcaster out there using a non-resonant antenna, unless it is part or a multi-antenna system and it is being used out of phase to decouple other parts of the antenna. Stirba curtains/rombics & Beverages are all multi-antennas used to make up a single antenna system. The antenna system is resonant, even tho it is made up of both resonant and non-resonant elements. Here is another great link... http://www.radio-electronics.com/info/antennas/basics/resonance.php 73 de W4LGH - Alan http://www.w4lgh.com
Reply to a comment by : N1XBP on 2007-02-23

Sometimes I think eHam is a lost cause. I think this thread devolved after a bit of debate about receive/transmit performance not being equal on an antenna. Then someone misunderstood that as being false because of reciprocity of pattern and gain. Those are two seperate issues. If antennas transmit just as well as they receive, why don't we all transmit into beverages? Yes, reciprocity holds true for the pattern and gain, except in the real world the ground losses cause it to be a lousy transmit antenna. See the conceptual difference now? As for antenna resonance, there are circles being gone through here. The antenna and the antenna system are not exactly one in the same. I can have a resonant antenna system with a non resonant antenna element. Then, some people seem to think that you can't feed a non resonant antenna without a tuner. Not true if you pick a feed point that has the impedance you want for the frequency you intend to use. What your pattern will look like is another story. And last, 1:1 SWR isn't entirely related to resonance, since impedance is a complex number and a high non reactive componant will lower the SWR by lowering the Q of the tuned circuit the antenna system represents and burning up more of the power that would have been reflected as heat.
Reply to a comment by : AA4PB on 2007-02-23

Alan, I submit that the ends of a dipole (resonant or not) are ALWAYS open and ALWAYS high impedance. That is exactly what makes the feed impedance of a dipole change as you change its physical length. When each side of a dipole is an exact odd multiple of 1/4 wavelength long then the standing wave on the antenna transforms the high impedance at the end to a fairly low impedance at the center. If the antenna is some other (non-resonant) length then the standing wave transforms the high impedance at the end to some other impedance at the center. As long as you can match that impedance to the feed line you can transfer power into the antenna. If you can transfer power into an antenna then most of it (less the small I*R loss in the resistance of the wire) will be radiated. An antenna has basically two ways to get rid of the power that gets applied to it. Either is is radiated or it is turned to heat. The only thing that can turn it to heat is the resistance of the wire. Since the resistance of the wire in a typical doublet antenna is very low, most of the power must be radiated. Making an antenna a non-resonant length does not change the resistance of the wire therefore it doesn't raise the amount of power disipated as heat by any significant amount.
Reply to a comment by : AD4U on 2007-02-23

Doing something to add 1 or 2 dB to your signal may not make much difference by itself. However if you have the $$ and the time and the expertise, making changes that add a dB here and a dB there and another dB somewhere else, collectively WILL make a noticeable difference. This is often what separates the BIG GUNS from the little pistols.
W8JI2007-02-23
RE: Benchmarks
by W4LGH on February 23, 2007

I have been a broadcast engineer for 30+ years, Ham radio and 1st class license for 43+ years.

Someone does understand where I have been coming from. Yes Am broadcast towers, except a few at the hi end of the band are less than a 1/4wave.>>


Actually most AM BC towers were taller than 1/4 wave, not shorter.

In any even very few are intentionally made self-resonant. There are very few 85-90 degree tall towers.

73 Tom
Reply to a comment by : W4LGH on 2007-02-23

K0IZ wrote.."Not sure about your long-term broadcast experience, but ... Broadcast band antennas (towers) are rarely (if ever) full 1/4 wave verticals. No problem - a matching network at the base cancels the reactance. Other than slight loss in the network, all of the transmitter power is radiated. THe antenna is NOT resonant, the antenna system IS. So ... several thousand examples." I have been a broadcast engineer for 30+ years, Ham radio and 1st class license for 43+ years. Someone does understand where I have been coming from. Yes Am broadcast towers, except a few at the hi end of the band are less than a 1/4wave. You add a matching network to tune out the reactance, therefore making the antenna system resonant. Hams do the same thing. I also want to set the record staight, that I never said an antenna had to resonant to work, I said it was at it PEAK effeciency at resonance! I have also NEVER mentioned an SWR of 1:1 in order for it to work. My antennas are NOT 1:1 and anything under 3:1 works ok for me. I also said you CAN NOT tune your antenna with an antenna tuner in your shack hooked to un-balanced line(coax). You can however tune the antenna with a tuner or matching network AT the antenna, this is done all the time with load coils, and other matching networks, and these devices are used to make the antenna resonate, which has to do with resonance. And I also agree with the poster about speakers and antennas. A speaker to an AF amp is exactly the same as an antenna to an RF amp. The same principles apply only at lower audio frequencies. Everything in life is relative, and there is nothing new under the Sun! 73 de W4LGH Alan http://www.w4lgh.com
Reply to a comment by : KC8QFP on 2007-02-23

AA4PB sez, ""Think of a matchbox as an output transformer on an amplifier. It matches the impedance of the speaker load to the impedance of the output tubes or transistors. Yes, transformers are still used in commercial audio amplifiers, primarily to match to a 70V distributed paging speaker system."" I would compare an output transformer to a BALUN or torroidial transformer, and not so much the caps and coils that direct the stray RF to ground. An Lpad has a hi-wattage resistor (often coil type) that diverts some of the power through the resistor, and some to the speaker. i.e. a transformer converts as in 4:1 etc., and a matchbox DIVERTS the RF. A matchbox is more akin to filters than transformers. transformers - converts matchbox/filters - diverts Let's say you have a two ohm speaker that you would like to connect to an eight ohm amp. Here are a few ways to do it. One would be to put a six ohm resistor (Lpad/reostat) series inline to the speaker (like a matchbox to me). Another way would be to use a (impedance) transformer (this would be connected in parellel). Another would be to use more speakers in series (my preferred method, like a resonant antenna). Antenna feedline does radiate some of the stray reflected RF, but a lot of it either seeks a path to ground through a tuner or the transmitter. It is called standing wave because it does NOT radiate efficiantly like an antenna. So speaker wire is simular. Radiation and dicipation is simply electricity seeking the lowest path of resistance, i.e. finding its easiest way to complete the circuit. Some finds its way by radiating from an antenna, as RF through space, to the other guys antenna and then through his receiver so to speak. Some energy finds a shortcut to ground through a tuner. The lowest possible path of resistance would be a short circuit because it is the "shortest" or least path of resistance.
Reply to a comment by : AA4PB on 2007-02-23

Speakers and audio amplfiers are quite different than antennas and RF. The wires connecting the speakers are very short in terms of the wavelength of the audio and they do not act as transmission lines. You don't have to deal with standing waves and reflected power on the speaker wires. It is true however that maximum power is transferred from the source to the load when the load impedance matches the source impedance. That's akin to matching the antenna SYSTEM to the transmitter which is why matchboxes are often used. It doesn't relate to resonance of an antenna however. Think of a matchbox as an output transformer on an amplifier. It matches the impedance of the speaker load to the impedance of the output tubes or transistors. Yes, transformers are still used in commercial audio amplifiers, primarily to match to a 70V distributed paging speaker system.
Reply to a comment by : AA4PB on 2007-02-23

Alan, I submit that the ends of a dipole (resonant or not) are ALWAYS open and ALWAYS high impedance. That is exactly what makes the feed impedance of a dipole change as you change its physical length. When each side of a dipole is an exact odd multiple of 1/4 wavelength long then the standing wave on the antenna transforms the high impedance at the end to a fairly low impedance at the center. If the antenna is some other (non-resonant) length then the standing wave transforms the high impedance at the end to some other impedance at the center. As long as you can match that impedance to the feed line you can transfer power into the antenna. If you can transfer power into an antenna then most of it (less the small I*R loss in the resistance of the wire) will be radiated. An antenna has basically two ways to get rid of the power that gets applied to it. Either is is radiated or it is turned to heat. The only thing that can turn it to heat is the resistance of the wire. Since the resistance of the wire in a typical doublet antenna is very low, most of the power must be radiated. Making an antenna a non-resonant length does not change the resistance of the wire therefore it doesn't raise the amount of power disipated as heat by any significant amount.
Reply to a comment by : AD4U on 2007-02-23

Doing something to add 1 or 2 dB to your signal may not make much difference by itself. However if you have the $$ and the time and the expertise, making changes that add a dB here and a dB there and another dB somewhere else, collectively WILL make a noticeable difference. This is often what separates the BIG GUNS from the little pistols.
NC2W2007-02-23
Benchmarks
Isn't SWR simply a measure of how different the antenna feed point impedance is from the characteristic impedance of the feed line?

For systems where the transceiver output impedance is similar to the feedline impedance, SWR is measure of antenna mismatch.

While it doesn't tell the operator everything, SWR measurements are easy to make, and thus get built into modern radios.

Cosmetically, it's a replacement for the multipurpose meter on a tube rig.
KY1V2007-02-23
RE: Benchmarks
>RE: Benchmarks Reply
by KY1V on February 23, 2007 Mail this to a friend!

Yeah, that's how I want to spend my weekends, picking through garbage for antenna wire...

Good Grief!

David ~ KY1V<

::I plan to spend my retirement dumpster diving, because I didn't get much of this earlier.

:-)

WB2WIK/6

------------------------

Maybe you can find a hardly used CapcitiveReciprocityMicroHomeBrewCoaxialDynamic Antenna wire in one of those and talk to me in Jamaica!

I think I can hear you on your dummy load!

David ~ KY1V
Reply to a comment by : WB2WIK on 2007-02-23

>RE: Benchmarks Reply by KY1V on February 23, 2007 Mail this to a friend! Yeah, that's how I want to spend my weekends, picking through garbage for antenna wire... Good Grief! David ~ KY1V< ::I plan to spend my retirement dumpster diving, because I didn't get much of this earlier. :-) WB2WIK/6
Reply to a comment by : KY1V on 2007-02-23

Yeah, that's how I want to spend my weekends, picking through garbage for antenna wire... Good Grief! David ~ KY1V
Reply to a comment by : N0AH on 2007-02-23

I say plug in coax to radio. Then feed coax to antenna. Check for any potetial problems. Have fun...bench that-
W4LGH2007-02-23
RE: Benchmarks
I'm done. K4IUQ, I said I wasn't going to stoop to name calling. That wasn't in and early on post, that came much later. Your early on post said if you couldn't tune your antenna with an antenna tuner in your shack, why then do they build them in radios. I said I wasn't going to go into that, but I'm done now...so the reason they put antenna tuners in radios is so F#$KING IDIOTS like you will BUY THEM!!

Yall do what you want, believe what you want to believe. Just play radio!

Reply to a comment by : KY1V on 2007-02-23

Oh, and don't get your panties in a wad...I am just joking! Congrats on getting your Extra class ticket! DAvid ~ KY1V
Reply to a comment by : KY1V on 2007-02-23

wait... maybe Sicily...special event call... IS2D... "I Saved 2 Dollars" David ~ KY1V
Reply to a comment by : KY1V on 2007-02-23

By the way, nice vanity call...no wonder you couldn't afford wire!!! Perhaps next time move to Wales and go for GW4A.. "Garbage Wire 4 Antenna" 8~) David ~ KY1V
Reply to a comment by : KY1V on 2007-02-23

Yeah, that's how I want to spend my weekends, picking through garbage for antenna wire... Good Grief! David ~ KY1V
Reply to a comment by : N0AH on 2007-02-23

I say plug in coax to radio. Then feed coax to antenna. Check for any potetial problems. Have fun...bench that-
WB2WIK2007-02-23
RE: Benchmarks
>RE: Benchmarks Reply
by KY1V on February 23, 2007 Mail this to a friend!

Yeah, that's how I want to spend my weekends, picking through garbage for antenna wire...

Good Grief!

David ~ KY1V<

::I plan to spend my retirement dumpster diving, because I didn't get much of this earlier.

:-)

WB2WIK/6
Reply to a comment by : KY1V on 2007-02-23

Yeah, that's how I want to spend my weekends, picking through garbage for antenna wire... Good Grief! David ~ KY1V
Reply to a comment by : N0AH on 2007-02-23

I say plug in coax to radio. Then feed coax to antenna. Check for any potetial problems. Have fun...bench that-
WB2WIK2007-02-23
RE: Benchmarks
>RE: Benchmarks Reply
by KD2BD on February 23, 2007 Mail this to a friend!
I think what this calculations demonstrates is the reduction in a resonant antenna's effective capture area as frequency is raised. This is a property that most certainly obeys the theory of reciprocity.<

::That's not true. Where'd you find this information?

>Antenna gain is directly related to effective capture area (and frequency). It is impossible for an antenna to have different gain on RX than it does on TX.<

::That can be true if there is no transmission line, at all. As soon as you add a transmission line, this statement doesn't hold. Tom W8JI (posting above) explained why.

>An antenna's effective capture area is most often a term that is absorbed into free space path loss calculations.<

::It is? Where? Free space path loss is very well understood and calculable and isn't related to antennas used.

>It is well understood that as frequency is increased, the free space path loss also increases. In reality, free space is lossless.<

::In a vacuum (no atmosphere, no ionosphere), this is close. But we don't work in free space.

>It doesn't care about frequency. Signals traveling across free space get weaker as frequency is raised due to the reduction in effective capture areas of the antennas on each end of the RF circuit.<

::What?

>A parabolic dish is an exception to the rule. A parabolic dish maintains a constant effective capture area regardless of frequency. Dipoles, yagis, etc. do not.<

::What? Question: How do you calculate capture area? Let's see the formula you use.

-WB2WIK/6




Reply to a comment by : KD2BD on 2007-02-23

Steve, KAØGKT/7 wrote: > So, you can see that in order for a 70 cm antenna to > provide the same level of reception as a 6 m dipole, > the 70 cm antenna must have a 9.35 dBd gain. Hmmm... My calculations show over 18 dB for 6 meters, and a bit over 9.6 dB for 2-meters. Maybe you meant to say 2-meters instead of 6... I think what this calculations demonstrates is the reduction in a resonant antenna's effective capture area as frequency is raised. This is a property that most certainly obeys the theory of reciprocity. Antenna gain is directly related to effective capture area (and frequency). It is impossible for an antenna to have different gain on RX than it does on TX. Therefore, an antenna's effective capture area remains constant in either mode of operation as well. An antenna's effective capture area is most often a term that is absorbed into free space path loss calculations. It is well understood that as frequency is increased, the free space path loss also increases. In reality, free space is lossless. It doesn't care about frequency. Signals traveling across free space get weaker as frequency is raised due to the reduction in effective capture areas of the antennas on each end of the RF circuit. A parabolic dish is an exception to the rule. A parabolic dish maintains a constant effective capture area regardless of frequency. Dipoles, yagis, etc. do not. Incidentally, about the only thing that doesn't obey reciprocity in Amateur Radio work is propagation affected by Faraday rotation. It is believed that this affect sometimes results in "one-way propagation" conditions on HF. If you've ever seen WWVB (60 kHz) daytime coverage maps on NIST's web site (http://tf.nist.gov/stations/wwvbcoverage.htm), you've seen the affect of "one-way propagation". While WWVB's transmitter is located near Ft. Collins, CO, and radiates an omnidirectional pattern, nearly identical field strengths are observed at each coast of the USA, despite their unequal distances from the transmitter. The signal consistently propagates better going west to east, than it does going east to west during daylight hours over land. 73, de John, KD2BD
Reply to a comment by : KA0GKT on 2007-02-22

Carl - W9PMZ wrote: "antennas are NOT reciprocal in their transmit verses receive performance" Rewriting text books? Most antenna books that I have been privy to read starts the treatment of antennas by making a statement: "In this section we show that the radiation pattern of an antenna is the same whether it is used as a transmitting antenna or a receiving antenna. Reciprocity allows the calculation or measurement of an antenna pattern in either the transmit or receive case." (from Antenna Theory and Design by Stutzman and Thiele, page 40) Propagation at HF makes the antennas properties (height, length, etc) the issue, but the antenna still obeys reciprocity. Antennas do indeed behave differently on receive than on transmit. The phenominon is called the Dipole factor and it has been documented since the time when the current NTSC TV channels were being laid out in the late 1940s. Since this was calculated for TV, the benchmark for the dipole factor is in the range of 47 MHz which was the original channel One. As the operating frequency increases, for a fixed signal density, the voltage at the terminals of a properly terminated dipole will decrease. For instance, with a 1 micro-volt/meter field strength, the voltage at the terminals of a dipole cut to 30 MHz will be 1.59 micro-volts. At a dipole cut for 50 MHz it will be .955 micro-volts; a 144 MHz dipole will have .332 micro-volts; a 220 MHz dipole will have .215 micro-volts; at 432 there will be .11 micro-volts. The formula to calculate dipole factor is: Et = Ef x ((300/F)/(2 x Pi)) Where: Et = RF voltage across the properly terminated terminals of the dipole. Ef = Field Strength in Volts per Meter F = Frequency in MHz Pi = 3.142 So, you can see that in order for a 70 cm antenna to provide the same level of reception as a 6 m dipole, the 70 cm antenna must have a 9.35 dBd gain. It must be noted that the dipole factor is only a factor for reception, when transmitting, a dipole is a dipole is a dipole. 73 DE KAØGKT/7 --Steve
Reply to a comment by : W9PMZ on 2007-02-22

"antennas are NOT reciprocal in their transmit verses receive performance" Rewriting text books? Most antenna books that I have been privy to read starts the treatment of antennas by making a statement: "In this section we show that the radiation pattern of an antenna is the same whether it is used as a transmitting antenna or a receiving antenna. Reciprocity allows the calculation or measurement of an antenna pattern in either the transmit or receive case." (from Antenna Theory and Design by Stutzman and Thiele, page 40) Propagation at HF makes the antennas properties (height, length, etc) the issue, but the antenna still obeys reciprocity. 73, Carl - W9PMZ
Reply to a comment by : ONAIR on 2007-02-22

Interesting point. So a resonant vertical dipole would then be a lot more efficient than a vertical that you would need to tune?
KY1V2007-02-23
RE: Benchmarks

Oh, and don't get your panties in a wad...I am just joking!

Congrats on getting your Extra class ticket!

DAvid ~ KY1V
Reply to a comment by : KY1V on 2007-02-23

wait... maybe Sicily...special event call... IS2D... "I Saved 2 Dollars" David ~ KY1V
Reply to a comment by : KY1V on 2007-02-23

By the way, nice vanity call...no wonder you couldn't afford wire!!! Perhaps next time move to Wales and go for GW4A.. "Garbage Wire 4 Antenna" 8~) David ~ KY1V
Reply to a comment by : KY1V on 2007-02-23

Yeah, that's how I want to spend my weekends, picking through garbage for antenna wire... Good Grief! David ~ KY1V
Reply to a comment by : N0AH on 2007-02-23

I say plug in coax to radio. Then feed coax to antenna. Check for any potetial problems. Have fun...bench that-
KY1V2007-02-23
RE: Benchmarks
wait...

maybe Sicily...special event call...

IS2D... "I Saved 2 Dollars"

David ~ KY1V

Reply to a comment by : KY1V on 2007-02-23

By the way, nice vanity call...no wonder you couldn't afford wire!!! Perhaps next time move to Wales and go for GW4A.. "Garbage Wire 4 Antenna" 8~) David ~ KY1V
Reply to a comment by : KY1V on 2007-02-23

Yeah, that's how I want to spend my weekends, picking through garbage for antenna wire... Good Grief! David ~ KY1V
Reply to a comment by : N0AH on 2007-02-23

I say plug in coax to radio. Then feed coax to antenna. Check for any potetial problems. Have fun...bench that-
KY1V2007-02-23
RE: Benchmarks

By the way, nice vanity call...no wonder you couldn't afford wire!!!

Perhaps next time move to Wales and go for GW4A.. "Garbage Wire 4 Antenna"

8~)

David ~ KY1V
Reply to a comment by : KY1V on 2007-02-23

Yeah, that's how I want to spend my weekends, picking through garbage for antenna wire... Good Grief! David ~ KY1V
Reply to a comment by : N0AH on 2007-02-23

I say plug in coax to radio. Then feed coax to antenna. Check for any potetial problems. Have fun...bench that-
KY1V2007-02-23
RE: Benchmarks

Yeah, that's how I want to spend my weekends, picking through garbage for antenna wire...

Good Grief!

David ~ KY1V
Reply to a comment by : N0AH on 2007-02-23

I say plug in coax to radio. Then feed coax to antenna. Check for any potetial problems. Have fun...bench that-
N0AH2007-02-23
Benchmarks
I say plug in coax to radio. Then feed coax to antenna. Check for any potetial problems. Have fun...bench that-
K9IUQ2007-02-23
Benchmarks
W4LGH Says: I just went back thru all of your post and I did NOT see ANTENNA SYSTEM much less capitalize in any of them!

......................................................
You See and Believe what you want regardless of the truth and then try to spin things.

From A Earlier K9IUQ Post EASILY found using your browser Find key:

>>"We make the antenna SYSTEM resonant with a tuner of one kind or another or live with SWR higher than 1:1.

Agreed - the whole SYSTEM must be resonance -from the radio to the antenna. It makes little difference if the antenna itself is resonance or not.Many of the best performing wire antennas are non-resonant fed with open wire feeders and an antenna tuner.

Also resonance of the SYSTEM has nothing to do with how well the antenna radiates."

...................................................
Do You see SYSTEM or antenna System anywhere in the above post? Is ANY OF IT CAPITALIZED? Are you Blind??
Do you possibly think MAYBE I capitalized SYSTEM to make sure you got the point???????

Your apology goes here--------

I have been quite restrained in my replys to you but you have been going too far with your crap.

W6TH --"W4LGH Alan,
I've heard enough of your bullshit, enough is enough.

Said by a ham one can respect..


K9IUQ











WG8Z2007-02-23
Benchmarks
Hmmm Benchmarks?
Well my benchmark;
Swan 500c $100
Johnson Matchbox jr $40
Shure 8800 Microphone $19.99
50ft 450 Windowline $10.00
130' #14awg thhn, Garbage picked.
Money invested <$200.00
Results
Works FB 10m thru 80m
Sig. reports generally 59+ big signal, very good
audio.

I'm Happy
73 Greg
WG*Z

W4LGH2007-02-23
RE: Benchmarks
K9IUQ says: NOT TRUE. Go back and re-read one of my earlier posts where I REPEATEDLY said ANTENA SYSTEM and made a point of putting it in all capitals several times to differentiate from an antenna.
==============================

I just went back thru all of your post and I did NOT see ANTENNA SYSTEM much less capitalize in any of them! I am not going to debate this with an @$#^%#!
Went back and changed it, not going to stoop to name calling.

Funny that I have received many email from Broadcast engineers saying the agree with me and understood what I was saying. No spins here, I stand by what I said 100%, my mistake was assuming that saying antenna ,it was the assumption the entire system, as an antenna hanging in tree with no feed line isn't gonna do anyone any good. My mistake for assuming.

73 de W4LGH - Alan
http://www.w4lgh.com

Reply to a comment by : K9IUQ on 2007-02-23

KB1MQR says: What I would really like is a good quantative analysis and measurement of the losses from a common transciever, thru a populat tuner, via standard coza to a popular antenna. This one case would provide real insight on effeciency, SWR and the benefits and loses normally over look. ....................................................... QST Magazine has reviewed most of the popular tuners. These reviews include measuring power loss in the tuner. The reviews are available on the ARRL website if you are a member. The reviews make for VERY interesting and is one reason I use a TEN-TEC 238B tuner which is a L-network tuner vs most the others are T Network tuners. Losses from coax can be obtained from several places on the net. Stan K9IUQ
K9IUQ2007-02-23
Benchmarks
KB1MQR says: What I would really like is a good quantative analysis and measurement of the losses from a common transciever, thru a populat tuner, via standard coza to a popular antenna. This one case would provide real insight on effeciency, SWR and the benefits and loses normally over look.

.......................................................
QST Magazine has reviewed most of the popular tuners. These reviews include measuring power loss in the tuner. The reviews are available on the ARRL website if you are a member. The reviews make for VERY interesting and is one reason I use a TEN-TEC 238B tuner which is a L-network tuner vs most the others are T Network tuners.

Losses from coax can be obtained from several places on the net.

Stan K9IUQ
K9IUQ2007-02-23
Benchmarks
W4LGH says
OK, I guess no one is understanding that "The Antenna" is the antenna system, and the entire system HAS to be RESONANT!
...............................................
K9IUQ says: NOT TRUE. Go back and re-read one of my earlier posts where I REPEATEDLY said ANTENA SYSTEM and made a point of putting it in all capitals several times to differentiate from an antenna. MANY others even described the antenna system from the radio to the antenna. You saw only what you wanted to see. Now that you been beaten up here on this subject and your balloon has been deflated, go back and read what I and many others said about ANTENNA SYSTEMS.

Most Hams know the ANTENNA SYSTEM has to be resonant or the antenna load will not accept power. Put an antenna tuner in the coax line and the tuner becomes part of the ANTENNA SYSTEM and makes the whole system resonate.

Nowhere did I see you mention the ANTENNA SYSTEM, you just kept going on about:

"The idea of an antenna tuner hooked to an un-balanced line (coax) is absurd"

"a RESONATE antenna will work BETTER than a NON_RESONATE antenna"
.....................................................
K9IUQ says - Both very in-accurate statements that was pointed out by many Hams much smarter than you or I.

Spin your story and facts now any way you want, one only has to go back and reread your posts to find the truth of what you said.

.........................................
W4LGH Says "I think I have figured out what has been missing here in the translations"

K9IUQ says: I suggest you are missing more than translations........

Stan K9IUQ










KD2BD2007-02-23
RE: Benchmarks
Steve, KAØGKT/7 wrote:

> So, you can see that in order for a 70 cm antenna to
> provide the same level of reception as a 6 m dipole,
> the 70 cm antenna must have a 9.35 dBd gain.

Hmmm... My calculations show over 18 dB for 6 meters, and a bit over 9.6 dB for 2-meters. Maybe you meant to say 2-meters instead of 6...

I think what this calculations demonstrates is the reduction in a resonant antenna's effective capture area as frequency is raised. This is a property that most certainly obeys the theory of reciprocity.

Antenna gain is directly related to effective capture area (and frequency). It is impossible for an antenna to have different gain on RX than it does on TX. Therefore, an antenna's effective capture area remains constant in either mode of operation as well.

An antenna's effective capture area is most often a term that is absorbed into free space path loss calculations.

It is well understood that as frequency is increased, the free space path loss also increases. In reality, free space is lossless. It doesn't care about frequency. Signals traveling across free space get weaker as frequency is raised due to the reduction in effective capture areas of the antennas on each end of the RF circuit.

A parabolic dish is an exception to the rule. A parabolic dish maintains a constant effective capture area regardless of frequency. Dipoles, yagis, etc. do not.

Incidentally, about the only thing that doesn't obey reciprocity in Amateur Radio work is propagation affected by Faraday rotation. It is believed that this affect sometimes results in "one-way propagation" conditions on HF.

If you've ever seen WWVB (60 kHz) daytime coverage maps on NIST's web site (http://tf.nist.gov/stations/wwvbcoverage.htm), you've seen the affect of "one-way propagation". While WWVB's transmitter is located near Ft. Collins, CO, and radiates an omnidirectional pattern, nearly identical field strengths are observed at each coast of the USA, despite their unequal distances from the transmitter. The signal consistently propagates better going west to east, than it does going east to west during daylight hours over land.


73, de John, KD2BD
Reply to a comment by : KA0GKT on 2007-02-22

Carl - W9PMZ wrote: "antennas are NOT reciprocal in their transmit verses receive performance" Rewriting text books? Most antenna books that I have been privy to read starts the treatment of antennas by making a statement: "In this section we show that the radiation pattern of an antenna is the same whether it is used as a transmitting antenna or a receiving antenna. Reciprocity allows the calculation or measurement of an antenna pattern in either the transmit or receive case." (from Antenna Theory and Design by Stutzman and Thiele, page 40) Propagation at HF makes the antennas properties (height, length, etc) the issue, but the antenna still obeys reciprocity. Antennas do indeed behave differently on receive than on transmit. The phenominon is called the Dipole factor and it has been documented since the time when the current NTSC TV channels were being laid out in the late 1940s. Since this was calculated for TV, the benchmark for the dipole factor is in the range of 47 MHz which was the original channel One. As the operating frequency increases, for a fixed signal density, the voltage at the terminals of a properly terminated dipole will decrease. For instance, with a 1 micro-volt/meter field strength, the voltage at the terminals of a dipole cut to 30 MHz will be 1.59 micro-volts. At a dipole cut for 50 MHz it will be .955 micro-volts; a 144 MHz dipole will have .332 micro-volts; a 220 MHz dipole will have .215 micro-volts; at 432 there will be .11 micro-volts. The formula to calculate dipole factor is: Et = Ef x ((300/F)/(2 x Pi)) Where: Et = RF voltage across the properly terminated terminals of the dipole. Ef = Field Strength in Volts per Meter F = Frequency in MHz Pi = 3.142 So, you can see that in order for a 70 cm antenna to provide the same level of reception as a 6 m dipole, the 70 cm antenna must have a 9.35 dBd gain. It must be noted that the dipole factor is only a factor for reception, when transmitting, a dipole is a dipole is a dipole. 73 DE KAØGKT/7 --Steve
Reply to a comment by : W9PMZ on 2007-02-22

"antennas are NOT reciprocal in their transmit verses receive performance" Rewriting text books? Most antenna books that I have been privy to read starts the treatment of antennas by making a statement: "In this section we show that the radiation pattern of an antenna is the same whether it is used as a transmitting antenna or a receiving antenna. Reciprocity allows the calculation or measurement of an antenna pattern in either the transmit or receive case." (from Antenna Theory and Design by Stutzman and Thiele, page 40) Propagation at HF makes the antennas properties (height, length, etc) the issue, but the antenna still obeys reciprocity. 73, Carl - W9PMZ
Reply to a comment by : ONAIR on 2007-02-22

Interesting point. So a resonant vertical dipole would then be a lot more efficient than a vertical that you would need to tune?
N4KC2007-02-23
RE: No Myth
Allow me to take issue with SSB's contention that this discussion has been a "waste of resources." I've learned a few things, and, in making an argument or two, strengthened my own limited knowledge of antenna theory. I trust others--some who responded and some who did not--now have a better idea of how RF ultimately gets transmitted and received. Some of the links provided also were helpful. And only a couple of times did the discussion degenerate into name-calling...which is, by the way, a "waste of resources."

AA4PB, you are my hero! Your posts are uniformly clear and well-reasoned...and not just because I agree with your position on this resonant/non-resonant-antenna thing.

W4LGH, I still follow your reasoning on many points, but you are very, very wrong when you say standing waves are lost to heat. At least that is the way I interpreted your statement. As has been said several times here, the energy that becomes reflected waves is almost always radiated by the antenna unless they are lost in some other way, such as with lossy feedline. And I cannot think of a single incidence in which the relative resonance of a radiator would have any effect whatsoever on the gain of that radiator. Help me understand that contention.

And I think KA0GKT (who had some very good points) confused some of us in listing those "resonant" and "non-resonant" antennas. I know he meant that they are DESIGNED to be resonant, but if operated somewhere else besides their design frequencies, they become decidely non-resonant the farther away you stray from their design frequencies. But there are also many other resonant points for the same antenna up and down the spectrum. Heck, even W4LGH's ten-penny nail is a resonant antenna somewhere!

Finally, I wade into the swirling waters of antenna reciprocity with great trepidation, but seems to me we are all pretty well saying the same thing. Receive and transmit properties for the same aerial should be roughly the same unless you consider noise. We use a Beverage for receive because it receives "good RF" well and "bad RF" (noise) not so well. Lower noise floor means the same signal that would be lost in the hiss and sputter is now readable. The Beverage is not such a good tranmitting antenna for several reasons, and would not necessarily be a better receiving antenna except for that noise thing.

Let the debate rage on! That's how we learn--by knowing what is correct and teaching others and by being wrong and having someone explain to us.

73,

Don N4KC
www.donkeith.com

Reply to a comment by : W4EF on 2007-02-23

W4LGH wrote >>This is getting good now...In order for a long wire antenna to show GAIN in a favorable direction, the antenna has to be resonant on the main frequency or some equal multiples of the main frequency, such as 2 wavelengths, or 3wavelengths etc. That being the case, then the antenna is resonant and your long wire antenna becomes a multi-phased array which beams more signal in one direction. Now an odd length wire say 2.5 wavelengths of the operating freq. will have 2 resonant sections which are in phase, with a non-resonant section to decouple the 2 in-phase and you can control the direction you beam it. << What about the terminated Rhombic? It's a good example of a highly directional non-resonant antenna that has been used extensively in commercial installations. Granted its not terribly efficient (~50%), but the notion that a long wire will only show directivity when its operated at a frequency where the radiator is an exact integer multiple of a wavelength at that operating frequency is simply absurd. I mean are you saying that the gain of a long wire antenna goes to zero the minute you drift off center frequency and the input reactance becomes non-zero? And what about the 5/8 wavelength vertical? By the standard definition, a 5/8 wave vertical is "non-resonant", but yet they are used ubiquitously because of their gain properties. 73, Mike W4EF..........
Reply to a comment by : AA4PB on 2007-02-22

Alan, yes I am an Extra since 1995. My first class radiotelephone, ship radar endorsement and all amateur exams except the Extra were taken in front of an FCC examiner. Since 1963 I've made my living in electronics so I might have just a little experience. I submit that you are absolutely wrong in your assertion that a resonant antenna element length radiates more of the applied signal than a non-resonant length. A non-resonant length will radiate all of the power applied to it (less any losses) just as well as a resonant length. If this is not so then please explain where the power that is applied to the element but not radiated goes. If, instead of attacking people's intelligence, you will take the time to review the text books I believe you'll find that what many people here are telling you is indeed true.
Reply to a comment by : W4LGH on 2007-02-22

W6TH Vito wrote.. ~"W4LGH Alan, I've heard enough of your bullshit, enough is enough."~ Well Mr Vito...That certainly was an educated response! I have seen it all in my career, from a 5 gallon bucket of dirt in a guys trunk, because the instructions said "This wire needs to go to EARTH ground", to a station engineer who wouldn't let anyone install any antennas upside down on his tower because he said, RF would leak out. I guess some people take things to litteral, and some don't take it litteral enough. A lot of good info in this thread, but again it goes to show you can not POST a good article here on eHam, no matter what, people will try to tear it apart. No one understands friendly debate. 73 de W4LGH - Alan
Reply to a comment by : W6TH on 2007-02-22

. W4LGH Alan, I've heard enough of your bullshit, enough is enough. W6TH .:
Reply to a comment by : W6TH on 2007-02-22

. Frequency = 1 divided by time. Time is relevant. Known as the Black Hole. No Myth. .:
Reply to a comment by : N3OX on 2007-02-22

"But the tuner was at the antenna feed point, matching the antenna impedance to the radio, it worked, and I certainly didn't have extra power to spare, but it would have worked BETTER, had the wire been resonant on the frequency I was using" Untrue.
Reply to a comment by : N3OX on 2007-02-22

W4LGH: The excerpt you quoted from that page explains that a center fed antenna has the lowest possible impedance when it's half-wave resonant (or three-halves or five halves, whatever); that is, if you fix the ***voltage*** you feed to an antenna, you'll get the most current, and therefore the biggest field, when it's an odd multiple of a half wave. If you force the same current in a similar, but nonresonant antenna, you get the same strength field (up to the antenna being a little bit shorter or longer which affects its gain in a minor fashion). If you had a magical transistor or tube that didn't care if the voltage was not in phase with the current and didn't care how high that voltage got, you would never have to match to a nonresonant antenna. We always say that we're "transforming the antenna impedance" with a network, but we could equally say "we're transforming the transmitter output up to a voltage with the proper phase to drive the a particular current into the antenna impedance" An article I found that's more precise: http://www.cv.nrao.edu/course/astr534/AntennaTheory.html There's a bunch of stuff later on that isn't particularly applicable to our current discussion, like the impedance of a black hole, but they do talk about reciprocity later on in the page. 73, Dan
Reply to a comment by : W6TH on 2007-02-22

. W4LGH We have been talking about transmitting antennas, I would like to know a specific purpose for using a non-resonant antenna on a transmitter. ..................................................... A long-wire antenna radiates more power in its most favorable direction than does a half wave resonant antenna in its most favorable direction. This power gain is secured at the expense of radiation in other directions. Would you like me to run some analytical Geometry for you? Maybe my math can convince you. Better yet, lets see what your math can do for me. 73, W6TH .:
Reply to a comment by : W4LGH on 2007-02-22

W6TH wrote..."This is no myth, but the truth. A resonant antenna and a non resonant antenna are both efficient antennas; non are better than the other, each has its own purpose for use." We have been talking about transmitting antennas, I would like to know a specific purpose for using a non-resonant antenna on a transmitter. If one truely understands resonance, I don't understand how anything can be as efficient as one that is resonant. And it is proven to you everytime you load up a transmitter. I certainly understand that weird things will work, but that doesn't make it so. I worked over 15 countries running 3 watts or less into a 50' wire fed at the end with an MFJ 16010 tuner. But the tuner was at the antenna feed point, matching the antenna impedance to the radio, it worked, and I certainly didn't have extra power to spare, but it would have worked BETTER, had the wire been resonant on the frequency I was using, certainly more efficient, as at resonancde the end of the wire looks like an open circuit, where as off resonance it begins to look like a short. 73 de W4LGH Alan http://www.w4lgh.com
Reply to a comment by : W6TH on 2007-02-22

. This is no myth, but the truth. A resonant antenna and a non resonant antenna are both efficient antennas; non are better than the other, each has its own purpose for use. W6TH .:
Reply to a comment by : WB2WIK on 2007-02-22

Not all solid state rigs reduce output power beginning at VSWR = 1.5. That is ultra conservative. The Ten Tec transceivers for years used a circuit breaker in the power supply to tell the transceiver when to "cut back power" due to high VSWR. They'd shut off! But until the breaker tripped, they'd keep transmitting. My Drake TR-7, by published specification, provides 90% of its full rated output power into a 2:1 VSWR and doesn't "fold back" to 50% (which is still about 75W output power) until VSWR = 5:1. That detail is listed here on the last page of the TR-7 brochure: http://wb4hfn.com/DRAKE/DrakeCatalogsBrochures/Brochure_TR7_04B.htm As such, the TR-7 hardly needs a tuner unless the user intends some pretty serious mismatches. Mine can easily produce 100W output power into a 3:1 mismatch, on any band. Without a tuner. It's largely a matter of "headroom" for the power amplifying devices selected. Margins include current, voltage and heat. One problem with a little rig like the FT-857 is its PA devices are small and its PA heatsink is *very* small, not capable of carrying much heat away from the devices, even with a fan. The TR-7 power amplifier heatsink alone (just the heatsink) is larger than the entire FT-857... WB2WIK/6
Reply to a comment by : K6HWH on 2007-02-22

"Every solidstate radio I have ever owned started shutting down power at a 1.5 swr." What about this? I have a Yaesu 857 that does indeed crank down transmit power if the SWR is the least bit off, ostensibly to prevent damage to the output transistors. If even a SWR of 5 does not diminish appreciable the antenna's ability to radiate, isn't this a mistake? Should I be looking for a way to defeat the 857's cautious approach to SWR?
Reply to a comment by : K3AN on 2007-02-22

This article is evidence that you can't determine the usefulness or accuracy of an article by the number of words. If you want useful, accurate information on antennas, please visit the L.B. Cebik web site www.cebik.com. For the last time, there is nothing magical about resonant antennas.
Reply to a comment by : N3OX on 2007-02-22

Respectfully, W4LGH, I would like to point out that you are the one muddying the waters about a *resonant antenna* and its radiating effectiveness. It is not true that antenna element resonance has anything to do with coupling power into the electromagnetic field around the antenna. The *REAL* part of the antenna impedance has two components, the radiation resistance and the loss resistance. That fraction of the power which is associated with "dissipation" in the radiation resistance is the power that gets radiated. The fraction associated with dissipation in the loss resistance goes up as heat. The power in the reactive part of the impedance is simply stored in fields around the antenna. That means that an antenna with an impedance of 70+j0 and one with an impedance of 70+j500 are radiating exactly the same amount of power if you can feed that power to them in the first place. You need to match the antenna system to the transmitter but resonance of the antenna element itself has nothing at all to do with the transfer of that power to radiating electromagnetic fields. If you are supplying 100W to the antenna, 100W minus the antenna losses is radiated, no matter whether or not the antenna element is resonant. 73, Dan
Reply to a comment by : W4LGH on 2007-02-22

You see, here we go again, a good article is written, it contains some great info. Some additional articles are written taken it a little further. Then come the people who truely do not understand what is being said, and either go on what they have seen, or what somebody else who truely doesn't understand told them. ==================================================== Now... AA4PB writes..."at resonance the antenna is inducing more power into the atmosphere ---------------------------------------------------- Can you point us to a definitive text that proves this, or even claims it to be true?" ==================================================== Now with a call like this, this guy is at least an "ADVANCED" class if not an "EXTRA" class, what I said is basic "Physics 101" Resonance is a common thread which runs through almost every branch of physics, and yet a lot of people have never studied it. Without resonance we wouldn't have radio, television, music, or swings on playgrounds, not to mention cool gismos like Tesla coils. Of course, resonance also has its dark side. It occasionally causes a bridge to collapse, a helicopter to fly apart, or other inconveniences. Unlike black holes, time travel, and quantum mechanics, resonance is common place and easy to observe. Yet, it is one of the most striking and unexpected phenomenon in all of physics. It is relative to everything. Here is a good link to read about it...hopefully it will explain.. http://www.intuitor.com/resonance/circuits.html Ever heard the term, "Dip the Plate" when tuning? Notice how the plate current drops but your output increases? Wonder why that is? Could it be your tank circuit has been tuned to resonance? Hmmm...your antenna is an extension of your tank circuit. And to K9IUQ...who wrote..."Also resonance of the SYSTEM has nothing to do with how well the antenna radiates. This is determined by MANY other factors. I have a wonderful Dummy load antenna under my desk that is resonant on all HF bands, however it doesnt seem to radiate very well since I haven't worked too many people with it."... I give up here, this guy just isn't with the program...A dummy LOAD is NOT resonate, it is a resistive LOAD designed to burn up the power by turning it into HEAT! Thats why they call it a dummy LOAD! (key word there is LOAD) Man..you guys say you want elmers, if you truely do not understand something, thats ok, there are people who do understand, and more than willing to help. 73 de W4LGH Alan http://www.w4lgh.com
Reply to a comment by : AA4PB on 2007-02-22

at resonance the antenna is inducing more power into the atmosphere ---------------------------------------------------- Can you point us to a definitive text that proves this, or even claims it to be true?
Reply to a comment by : K9IUQ on 2007-02-22

One TRUE statement was made, a RESONATE antenna will work BETTER than a NON_RESONATE antenna. People do NOT understand resonance ..................................................... The above is an false statement. An Antenna is resonant at ONLY ONE frequency. At any other frequency it is non-resonant. We all use non-resonant antennas (including you) on a daily basis. We make the antenna SYSTEM resonant with a tuner of one kind or another or live with SWR higher than 1:1. Agreed - the whole SYSTEM must be resonance -from the radio to the antenna. It makes little difference if the antenna itself is resonance or not.Many of the best performing wire antennas are non-resonant fed with open wire feeders and an antenna tuner. Also resonance of the SYSTEM has nothing to do with how well the antenna radiates. This is determined by MANY other factors. I have a wonderful Dummy load antenna under my desk that is resonant on all HF bands, however it doesnt seem to radiate very well since I haven't worked too many people with it. Please Pick Up an antenna Book like "Reflections" and learn the facts instead of trying to sell me 'some wonderful ocean front property in Arizona " K9IUQ
W0IVJ2007-02-23
RE: Benchmarks
K6HWH said: What about this? I have a Yaesu 857 that does indeed crank down transmit power if the SWR is the least bit off, ostensibly to prevent damage to the output transistors. If even a SWR of 5 does not diminish appreciable the antenna's ability to radiate, isn't this a mistake? Should I be looking for a way to defeat the 857's cautious approach to SWR?
----------------------------------------------------------

The FT-857 not only folds back the power at an SWR of about 1.5:1, but it will distort the audio. It seems that Yaesu uses a poorly designed ALC circuit to fold back the power. This ALC circuit will produce noticeble audio distortion. I definitely would use a small high pass T tuner, or some other matching device, to match the impedance that is translated to the 857 due to the mismatch when the antenna impedance deviates much from 50 + j0. As long as the SWR on the coax is not very high (> 3:1) the losses in the coax and tuner combination will far outweigh the bad audio reports.

Tom W0IVJ
Reply to a comment by : K6HWH on 2007-02-22

"Every solidstate radio I have ever owned started shutting down power at a 1.5 swr." What about this? I have a Yaesu 857 that does indeed crank down transmit power if the SWR is the least bit off, ostensibly to prevent damage to the output transistors. If even a SWR of 5 does not diminish appreciable the antenna's ability to radiate, isn't this a mistake? Should I be looking for a way to defeat the 857's cautious approach to SWR?
Reply to a comment by : K3AN on 2007-02-22

This article is evidence that you can't determine the usefulness or accuracy of an article by the number of words. If you want useful, accurate information on antennas, please visit the L.B. Cebik web site www.cebik.com. For the last time, there is nothing magical about resonant antennas.
Reply to a comment by : N3OX on 2007-02-22

Respectfully, W4LGH, I would like to point out that you are the one muddying the waters about a *resonant antenna* and its radiating effectiveness. It is not true that antenna element resonance has anything to do with coupling power into the electromagnetic field around the antenna. The *REAL* part of the antenna impedance has two components, the radiation resistance and the loss resistance. That fraction of the power which is associated with "dissipation" in the radiation resistance is the power that gets radiated. The fraction associated with dissipation in the loss resistance goes up as heat. The power in the reactive part of the impedance is simply stored in fields around the antenna. That means that an antenna with an impedance of 70+j0 and one with an impedance of 70+j500 are radiating exactly the same amount of power if you can feed that power to them in the first place. You need to match the antenna system to the transmitter but resonance of the antenna element itself has nothing at all to do with the transfer of that power to radiating electromagnetic fields. If you are supplying 100W to the antenna, 100W minus the antenna losses is radiated, no matter whether or not the antenna element is resonant. 73, Dan
Reply to a comment by : W4LGH on 2007-02-22

You see, here we go again, a good article is written, it contains some great info. Some additional articles are written taken it a little further. Then come the people who truely do not understand what is being said, and either go on what they have seen, or what somebody else who truely doesn't understand told them. ==================================================== Now... AA4PB writes..."at resonance the antenna is inducing more power into the atmosphere ---------------------------------------------------- Can you point us to a definitive text that proves this, or even claims it to be true?" ==================================================== Now with a call like this, this guy is at least an "ADVANCED" class if not an "EXTRA" class, what I said is basic "Physics 101" Resonance is a common thread which runs through almost every branch of physics, and yet a lot of people have never studied it. Without resonance we wouldn't have radio, television, music, or swings on playgrounds, not to mention cool gismos like Tesla coils. Of course, resonance also has its dark side. It occasionally causes a bridge to collapse, a helicopter to fly apart, or other inconveniences. Unlike black holes, time travel, and quantum mechanics, resonance is common place and easy to observe. Yet, it is one of the most striking and unexpected phenomenon in all of physics. It is relative to everything. Here is a good link to read about it...hopefully it will explain.. http://www.intuitor.com/resonance/circuits.html Ever heard the term, "Dip the Plate" when tuning? Notice how the plate current drops but your output increases? Wonder why that is? Could it be your tank circuit has been tuned to resonance? Hmmm...your antenna is an extension of your tank circuit. And to K9IUQ...who wrote..."Also resonance of the SYSTEM has nothing to do with how well the antenna radiates. This is determined by MANY other factors. I have a wonderful Dummy load antenna under my desk that is resonant on all HF bands, however it doesnt seem to radiate very well since I haven't worked too many people with it."... I give up here, this guy just isn't with the program...A dummy LOAD is NOT resonate, it is a resistive LOAD designed to burn up the power by turning it into HEAT! Thats why they call it a dummy LOAD! (key word there is LOAD) Man..you guys say you want elmers, if you truely do not understand something, thats ok, there are people who do understand, and more than willing to help. 73 de W4LGH Alan http://www.w4lgh.com
Reply to a comment by : AA4PB on 2007-02-22

at resonance the antenna is inducing more power into the atmosphere ---------------------------------------------------- Can you point us to a definitive text that proves this, or even claims it to be true?
Reply to a comment by : K9IUQ on 2007-02-22

One TRUE statement was made, a RESONATE antenna will work BETTER than a NON_RESONATE antenna. People do NOT understand resonance ..................................................... The above is an false statement. An Antenna is resonant at ONLY ONE frequency. At any other frequency it is non-resonant. We all use non-resonant antennas (including you) on a daily basis. We make the antenna SYSTEM resonant with a tuner of one kind or another or live with SWR higher than 1:1. Agreed - the whole SYSTEM must be resonance -from the radio to the antenna. It makes little difference if the antenna itself is resonance or not.Many of the best performing wire antennas are non-resonant fed with open wire feeders and an antenna tuner. Also resonance of the SYSTEM has nothing to do with how well the antenna radiates. This is determined by MANY other factors. I have a wonderful Dummy load antenna under my desk that is resonant on all HF bands, however it doesnt seem to radiate very well since I haven't worked too many people with it. Please Pick Up an antenna Book like "Reflections" and learn the facts instead of trying to sell me 'some wonderful ocean front property in Arizona " K9IUQ
KE4ZHN2007-02-23
RE: Benchmarks
Hey Stan K9IUQ, I guess we`ll stick with our lousy nonresonant antennas huh? I`ll try to remember how lousy my antenna is the next time Im working VK`s and ZL`s barefoot on it.
Reply to a comment by : K9IUQ on 2007-02-23

From KE4HZN -Ah yes, the famous "it has to be cut to the band" crap. Pure unadulterated bull**it!! Tell all the broadcast engineers at every AM broadcast station in the world and every shortwave broadcast engineer in the world that their doing it all wrong by using nonresonant antennas. And then be prepared to be made a fool of by them when they laugh in your face and explain why your full of crap. ..................................................... Amazing isn't it how this "the antennas gotta be resonant" mis-information just keeps getting spread by un-knowledgeable hams. And the sad fact is Hams Like W4LGH fervently believe themselves and try to make believers out of everyone. For 46 years I have been a ham and this subject of resonant vs nonresonant antennas, my SWR better be low or it wont radiate, etc. keeps getting debated. I rarely get into the debate, past experience has taught me people don't want to take the time to study the antenna literature and learn the truth. Trying to convince Hams like W4LGH that they are wrong is like trying to convince a Republican that a Democrat can govern better. It just isn't going to happen. Stan K9IUQ
W4LGH2007-02-23
RE: No Myth
OK, I guess no one is understanding that "The Antenna" is the antenna system, and the entire system HAS to be RESONANT! A 5/8 vertical has a matching circuit at the base to match resonance to the transmitter. A rombic has a matching circuuit to match the resonance to the transmitter, altho personally I feel a rombic is better for receiving than for transmitting.

I still say you can NOT tune the antenna with a tuner inside you shack, hooked to un-balanced (coax), but you can match the impedance of the coax, losses will still exist. It would be much better to have the matching unit at the antenna. You can NOT put up a 5/8 wave length of wire and expect it to work without matching the resonance to the transmitter. I think I have figured out what has been missing here in the translations.

73 de W4LGH - Alan
http://www.w4lgh.com
Reply to a comment by : W4EF on 2007-02-23

W4LGH wrote >>This is getting good now...In order for a long wire antenna to show GAIN in a favorable direction, the antenna has to be resonant on the main frequency or some equal multiples of the main frequency, such as 2 wavelengths, or 3wavelengths etc. That being the case, then the antenna is resonant and your long wire antenna becomes a multi-phased array which beams more signal in one direction. Now an odd length wire say 2.5 wavelengths of the operating freq. will have 2 resonant sections which are in phase, with a non-resonant section to decouple the 2 in-phase and you can control the direction you beam it. << What about the terminated Rhombic? It's a good example of a highly directional non-resonant antenna that has been used extensively in commercial installations. Granted its not terribly efficient (~50%), but the notion that a long wire will only show directivity when its operated at a frequency where the radiator is an exact integer multiple of a wavelength at that operating frequency is simply absurd. I mean are you saying that the gain of a long wire antenna goes to zero the minute you drift off center frequency and the input reactance becomes non-zero? And what about the 5/8 wavelength vertical? By the standard definition, a 5/8 wave vertical is "non-resonant", but yet they are used ubiquitously because of their gain properties. 73, Mike W4EF..........
Reply to a comment by : AA4PB on 2007-02-22

Alan, yes I am an Extra since 1995. My first class radiotelephone, ship radar endorsement and all amateur exams except the Extra were taken in front of an FCC examiner. Since 1963 I've made my living in electronics so I might have just a little experience. I submit that you are absolutely wrong in your assertion that a resonant antenna element length radiates more of the applied signal than a non-resonant length. A non-resonant length will radiate all of the power applied to it (less any losses) just as well as a resonant length. If this is not so then please explain where the power that is applied to the element but not radiated goes. If, instead of attacking people's intelligence, you will take the time to review the text books I believe you'll find that what many people here are telling you is indeed true.
Reply to a comment by : W4LGH on 2007-02-22

W6TH Vito wrote.. ~"W4LGH Alan, I've heard enough of your bullshit, enough is enough."~ Well Mr Vito...That certainly was an educated response! I have seen it all in my career, from a 5 gallon bucket of dirt in a guys trunk, because the instructions said "This wire needs to go to EARTH ground", to a station engineer who wouldn't let anyone install any antennas upside down on his tower because he said, RF would leak out. I guess some people take things to litteral, and some don't take it litteral enough. A lot of good info in this thread, but again it goes to show you can not POST a good article here on eHam, no matter what, people will try to tear it apart. No one understands friendly debate. 73 de W4LGH - Alan
Reply to a comment by : W6TH on 2007-02-22

. W4LGH Alan, I've heard enough of your bullshit, enough is enough. W6TH .:
Reply to a comment by : W6TH on 2007-02-22

. Frequency = 1 divided by time. Time is relevant. Known as the Black Hole. No Myth. .:
Reply to a comment by : N3OX on 2007-02-22

"But the tuner was at the antenna feed point, matching the antenna impedance to the radio, it worked, and I certainly didn't have extra power to spare, but it would have worked BETTER, had the wire been resonant on the frequency I was using" Untrue.
Reply to a comment by : N3OX on 2007-02-22

W4LGH: The excerpt you quoted from that page explains that a center fed antenna has the lowest possible impedance when it's half-wave resonant (or three-halves or five halves, whatever); that is, if you fix the ***voltage*** you feed to an antenna, you'll get the most current, and therefore the biggest field, when it's an odd multiple of a half wave. If you force the same current in a similar, but nonresonant antenna, you get the same strength field (up to the antenna being a little bit shorter or longer which affects its gain in a minor fashion). If you had a magical transistor or tube that didn't care if the voltage was not in phase with the current and didn't care how high that voltage got, you would never have to match to a nonresonant antenna. We always say that we're "transforming the antenna impedance" with a network, but we could equally say "we're transforming the transmitter output up to a voltage with the proper phase to drive the a particular current into the antenna impedance" An article I found that's more precise: http://www.cv.nrao.edu/course/astr534/AntennaTheory.html There's a bunch of stuff later on that isn't particularly applicable to our current discussion, like the impedance of a black hole, but they do talk about reciprocity later on in the page. 73, Dan
Reply to a comment by : W6TH on 2007-02-22

. W4LGH We have been talking about transmitting antennas, I would like to know a specific purpose for using a non-resonant antenna on a transmitter. ..................................................... A long-wire antenna radiates more power in its most favorable direction than does a half wave resonant antenna in its most favorable direction. This power gain is secured at the expense of radiation in other directions. Would you like me to run some analytical Geometry for you? Maybe my math can convince you. Better yet, lets see what your math can do for me. 73, W6TH .:
Reply to a comment by : W4LGH on 2007-02-22

W6TH wrote..."This is no myth, but the truth. A resonant antenna and a non resonant antenna are both efficient antennas; non are better than the other, each has its own purpose for use." We have been talking about transmitting antennas, I would like to know a specific purpose for using a non-resonant antenna on a transmitter. If one truely understands resonance, I don't understand how anything can be as efficient as one that is resonant. And it is proven to you everytime you load up a transmitter. I certainly understand that weird things will work, but that doesn't make it so. I worked over 15 countries running 3 watts or less into a 50' wire fed at the end with an MFJ 16010 tuner. But the tuner was at the antenna feed point, matching the antenna impedance to the radio, it worked, and I certainly didn't have extra power to spare, but it would have worked BETTER, had the wire been resonant on the frequency I was using, certainly more efficient, as at resonancde the end of the wire looks like an open circuit, where as off resonance it begins to look like a short. 73 de W4LGH Alan http://www.w4lgh.com
Reply to a comment by : W6TH on 2007-02-22

. This is no myth, but the truth. A resonant antenna and a non resonant antenna are both efficient antennas; non are better than the other, each has its own purpose for use. W6TH .:
Reply to a comment by : WB2WIK on 2007-02-22

Not all solid state rigs reduce output power beginning at VSWR = 1.5. That is ultra conservative. The Ten Tec transceivers for years used a circuit breaker in the power supply to tell the transceiver when to "cut back power" due to high VSWR. They'd shut off! But until the breaker tripped, they'd keep transmitting. My Drake TR-7, by published specification, provides 90% of its full rated output power into a 2:1 VSWR and doesn't "fold back" to 50% (which is still about 75W output power) until VSWR = 5:1. That detail is listed here on the last page of the TR-7 brochure: http://wb4hfn.com/DRAKE/DrakeCatalogsBrochures/Brochure_TR7_04B.htm As such, the TR-7 hardly needs a tuner unless the user intends some pretty serious mismatches. Mine can easily produce 100W output power into a 3:1 mismatch, on any band. Without a tuner. It's largely a matter of "headroom" for the power amplifying devices selected. Margins include current, voltage and heat. One problem with a little rig like the FT-857 is its PA devices are small and its PA heatsink is *very* small, not capable of carrying much heat away from the devices, even with a fan. The TR-7 power amplifier heatsink alone (just the heatsink) is larger than the entire FT-857... WB2WIK/6
Reply to a comment by : K6HWH on 2007-02-22

"Every solidstate radio I have ever owned started shutting down power at a 1.5 swr." What about this? I have a Yaesu 857 that does indeed crank down transmit power if the SWR is the least bit off, ostensibly to prevent damage to the output transistors. If even a SWR of 5 does not diminish appreciable the antenna's ability to radiate, isn't this a mistake? Should I be looking for a way to defeat the 857's cautious approach to SWR?
Reply to a comment by : K3AN on 2007-02-22

This article is evidence that you can't determine the usefulness or accuracy of an article by the number of words. If you want useful, accurate information on antennas, please visit the L.B. Cebik web site www.cebik.com. For the last time, there is nothing magical about resonant antennas.
Reply to a comment by : N3OX on 2007-02-22

Respectfully, W4LGH, I would like to point out that you are the one muddying the waters about a *resonant antenna* and its radiating effectiveness. It is not true that antenna element resonance has anything to do with coupling power into the electromagnetic field around the antenna. The *REAL* part of the antenna impedance has two components, the radiation resistance and the loss resistance. That fraction of the power which is associated with "dissipation" in the radiation resistance is the power that gets radiated. The fraction associated with dissipation in the loss resistance goes up as heat. The power in the reactive part of the impedance is simply stored in fields around the antenna. That means that an antenna with an impedance of 70+j0 and one with an impedance of 70+j500 are radiating exactly the same amount of power if you can feed that power to them in the first place. You need to match the antenna system to the transmitter but resonance of the antenna element itself has nothing at all to do with the transfer of that power to radiating electromagnetic fields. If you are supplying 100W to the antenna, 100W minus the antenna losses is radiated, no matter whether or not the antenna element is resonant. 73, Dan
Reply to a comment by : W4LGH on 2007-02-22

You see, here we go again, a good article is written, it contains some great info. Some additional articles are written taken it a little further. Then come the people who truely do not understand what is being said, and either go on what they have seen, or what somebody else who truely doesn't understand told them. ==================================================== Now... AA4PB writes..."at resonance the antenna is inducing more power into the atmosphere ---------------------------------------------------- Can you point us to a definitive text that proves this, or even claims it to be true?" ==================================================== Now with a call like this, this guy is at least an "ADVANCED" class if not an "EXTRA" class, what I said is basic "Physics 101" Resonance is a common thread which runs through almost every branch of physics, and yet a lot of people have never studied it. Without resonance we wouldn't have radio, television, music, or swings on playgrounds, not to mention cool gismos like Tesla coils. Of course, resonance also has its dark side. It occasionally causes a bridge to collapse, a helicopter to fly apart, or other inconveniences. Unlike black holes, time travel, and quantum mechanics, resonance is common place and easy to observe. Yet, it is one of the most striking and unexpected phenomenon in all of physics. It is relative to everything. Here is a good link to read about it...hopefully it will explain.. http://www.intuitor.com/resonance/circuits.html Ever heard the term, "Dip the Plate" when tuning? Notice how the plate current drops but your output increases? Wonder why that is? Could it be your tank circuit has been tuned to resonance? Hmmm...your antenna is an extension of your tank circuit. And to K9IUQ...who wrote..."Also resonance of the SYSTEM has nothing to do with how well the antenna radiates. This is determined by MANY other factors. I have a wonderful Dummy load antenna under my desk that is resonant on all HF bands, however it doesnt seem to radiate very well since I haven't worked too many people with it."... I give up here, this guy just isn't with the program...A dummy LOAD is NOT resonate, it is a resistive LOAD designed to burn up the power by turning it into HEAT! Thats why they call it a dummy LOAD! (key word there is LOAD) Man..you guys say you want elmers, if you truely do not understand something, thats ok, there are people who do understand, and more than willing to help. 73 de W4LGH Alan http://www.w4lgh.com
Reply to a comment by : AA4PB on 2007-02-22

at resonance the antenna is inducing more power into the atmosphere ---------------------------------------------------- Can you point us to a definitive text that proves this, or even claims it to be true?
Reply to a comment by : K9IUQ on 2007-02-22

One TRUE statement was made, a RESONATE antenna will work BETTER than a NON_RESONATE antenna. People do NOT understand resonance ..................................................... The above is an false statement. An Antenna is resonant at ONLY ONE frequency. At any other frequency it is non-resonant. We all use non-resonant antennas (including you) on a daily basis. We make the antenna SYSTEM resonant with a tuner of one kind or another or live with SWR higher than 1:1. Agreed - the whole SYSTEM must be resonance -from the radio to the antenna. It makes little difference if the antenna itself is resonance or not.Many of the best performing wire antennas are non-resonant fed with open wire feeders and an antenna tuner. Also resonance of the SYSTEM has nothing to do with how well the antenna radiates. This is determined by MANY other factors. I have a wonderful Dummy load antenna under my desk that is resonant on all HF bands, however it doesnt seem to radiate very well since I haven't worked too many people with it. Please Pick Up an antenna Book like "Reflections" and learn the facts instead of trying to sell me 'some wonderful ocean front property in Arizona " K9IUQ
W0IVJ2007-02-23
RE: Benchmarks
W4LGH said: The idea of an antenna tuner hooked to an un-balanced line (coax) is absurd.

KB1MQR said: What I would really like is a good quantative analysis and measurement of the losses from a common transciever, thru a populat tuner, via standard coza to a popular antenna. This one case would provide real insight on effeciency, SWR and the benefits and loses normally over look.

After we have these quanitative facts, some suggestions for improvement would be greatly appreciated.

---------------------------------------------------------

Well, I just did some measurements and calculations , and here is what I did. I ran a TS-450 into an 80 meter dipole and recorded the SWR and power out that the TS-450 folds back to as measured by the meters on the Kenwood at several frequencies. I then simulated these SWR conditions using TLW, a transmission line calculator, for LMR400 and LMR200 coax. I also used TLW to create a high pass T tuner and computed the losses throughout the whole antenna system. When simulating the SWR, I always used a resistance lower than 50 ohms because it produces the highest losses in the tuner. Here are the results:

100 feet of RG-8 type LMR400 coax at 3.5 MHz
SWR____Power____FoldBackLoss____ CoaxLoss____ TunerLoss____ TotalLoss
1:1______100________0 db___________0.233 db________na__________0.23 db
2:1_______50________3 db___________0.250 db_______0.68 db_______0.93 db
3:1_______25________6 db___________0.317 db_______0.88 db_______1.20 db
>10:1_____10_______10 db___________0.862 db_______1.90 db_______2.76 db

100 feet of RG-58 type LMR200 coax at 3.5 MHz
SWR____Power____FoldBackLoss_____CoaxLoss____TunerLoss_____TotalLoss
1:1______100________0 db___________0.600 db________na_________0.60 db
2:1_______50________3 db___________0.673 db_______0.68 db______1.35 db
3:1_______25________6 db___________0.841 db_______0.86 db______1.70 db
>10:1_____10_______10 db___________2.069 db_______1.63 db______3.70 db

So you can see from these data that a high pass T tuner can be useful with modern solid state rigs where the power is folded back due to high SWR.

Tom W0IVJ
Reply to a comment by : W4LGH on 2007-02-22

This is a very interesting article, and touches on many points. The first is antenna GAIN. Altho I understand the principle very well, including how this gain is achieved, by beaming the radiated power more directional, I have always found the idea of saying an antenna has gain to be an oxymoron. When in fact an antenna (passive) can NOT produce any gain, it can however have less loss, but nothing is FREE, and once again compromises are made to get this gain. Another subject touched, DBI and DBD. Since you can NOT build an isotropic antenna on earth, and to my knowledge they haven't built one in free space yet, I find DBI to be an invalid rating and useless. DBD however is a more valid rating and since we CAN build dipoles on earth to compair to, the rating is more realistic. However you'll hardly ever is a DBD rating on an antenna. The idea of an antenna tuner hooked to an un-balanced line (coax) is absurd. The only thing you are tuning is the impedance at the shack end of the coax. The mis-match at the antenna still exsists and is still very REAL!! It may allow you to do something you couldn't without it, but you are only fooling yourself! Not to mention the other factor touched on, loss in the tuner..the best tuner made will have between an 11% to 15% loss!! Some of the cheaper tuners go way higher, as much as 40%!! Now you take your ant that has a 3:1 swr ratio, which is about a 25% loss, 3db loss in your coax, and a 15% loss in your tuner. Your meter on the tuner now shows 1:1 swr, output from your radio is showing a full 100watts, and you are HAPPY, but actually here is what you have...approx. 100-15(tuner loss)=85-42.5(3dbcoax)=42.5-10.5(3:1swr)= 32 watts!!! 1/3 of your power is being radiated!!! Not very good, but your meter says 100watts and you are happy. You will NOT find a tuner in use in my shack! I own a little MFJ941E piece of junk, but was using it to match a long wire to a receiver. Those figures above also work on your receiver too! Altho quite different, there is a big loss in your receive signal as well. Hope all this gives you something to think about. Al of my antennas are resonate, and are fed with LMR-400 cable (basically no loss @ HF) I have measured my power leaving the shack @ 100watts, and at the antenna there will be 98watts! This was done not so much for transmit, but for the receive side. If you can't hear them, you CAN NOT talk to them!!!! I do NOT claim my figures to be 100% accurate, but close enough to show an example of whats happening. 73 de W4LGH - Alan http://www.w4lgh.com
Reply to a comment by : NORTHCOUNTRY on 2007-02-22

My ant is monoband resonant on 40m but I use a tuner anyway. The tuner does not tune it on any other band. Picture here: http://i32.photobucket.com/albums/d43/Tom838/3-500Z%20pics/40mant.jpg
W4EF2007-02-23
RE: No Myth
W4LGH wrote >>This is getting good now...In order for a long wire antenna to show GAIN in a favorable direction, the antenna has to be resonant on the main frequency or some equal multiples of the main frequency, such as 2 wavelengths, or 3wavelengths etc. That being the case, then the antenna is resonant and your long wire antenna becomes a multi-phased array which beams more signal in one direction. Now an odd length wire say 2.5 wavelengths of the operating freq. will have 2 resonant sections which are in phase, with a non-resonant section to decouple the 2 in-phase and you can control the direction you beam it. <<

What about the terminated Rhombic? It's a good example of a highly directional non-resonant antenna that has been used extensively in commercial installations. Granted its not terribly efficient (~50%), but the notion that a long wire will only show directivity when its operated at a frequency where the radiator is an exact integer multiple of a wavelength at that operating frequency is simply absurd. I mean are you saying that the gain of a long wire antenna goes to zero the minute you drift off center frequency and the input reactance becomes non-zero?

And what about the 5/8 wavelength vertical? By the standard definition, a 5/8 wave vertical is "non-resonant", but yet they are used ubiquitously because of their gain properties.

73, Mike W4EF..........

Reply to a comment by : AA4PB on 2007-02-22

Alan, yes I am an Extra since 1995. My first class radiotelephone, ship radar endorsement and all amateur exams except the Extra were taken in front of an FCC examiner. Since 1963 I've made my living in electronics so I might have just a little experience. I submit that you are absolutely wrong in your assertion that a resonant antenna element length radiates more of the applied signal than a non-resonant length. A non-resonant length will radiate all of the power applied to it (less any losses) just as well as a resonant length. If this is not so then please explain where the power that is applied to the element but not radiated goes. If, instead of attacking people's intelligence, you will take the time to review the text books I believe you'll find that what many people here are telling you is indeed true.
Reply to a comment by : W4LGH on 2007-02-22

W6TH Vito wrote.. ~"W4LGH Alan, I've heard enough of your bullshit, enough is enough."~ Well Mr Vito...That certainly was an educated response! I have seen it all in my career, from a 5 gallon bucket of dirt in a guys trunk, because the instructions said "This wire needs to go to EARTH ground", to a station engineer who wouldn't let anyone install any antennas upside down on his tower because he said, RF would leak out. I guess some people take things to litteral, and some don't take it litteral enough. A lot of good info in this thread, but again it goes to show you can not POST a good article here on eHam, no matter what, people will try to tear it apart. No one understands friendly debate. 73 de W4LGH - Alan
Reply to a comment by : W6TH on 2007-02-22

. W4LGH Alan, I've heard enough of your bullshit, enough is enough. W6TH .:
Reply to a comment by : W6TH on 2007-02-22

. Frequency = 1 divided by time. Time is relevant. Known as the Black Hole. No Myth. .:
Reply to a comment by : N3OX on 2007-02-22

"But the tuner was at the antenna feed point, matching the antenna impedance to the radio, it worked, and I certainly didn't have extra power to spare, but it would have worked BETTER, had the wire been resonant on the frequency I was using" Untrue.
Reply to a comment by : N3OX on 2007-02-22

W4LGH: The excerpt you quoted from that page explains that a center fed antenna has the lowest possible impedance when it's half-wave resonant (or three-halves or five halves, whatever); that is, if you fix the ***voltage*** you feed to an antenna, you'll get the most current, and therefore the biggest field, when it's an odd multiple of a half wave. If you force the same current in a similar, but nonresonant antenna, you get the same strength field (up to the antenna being a little bit shorter or longer which affects its gain in a minor fashion). If you had a magical transistor or tube that didn't care if the voltage was not in phase with the current and didn't care how high that voltage got, you would never have to match to a nonresonant antenna. We always say that we're "transforming the antenna impedance" with a network, but we could equally say "we're transforming the transmitter output up to a voltage with the proper phase to drive the a particular current into the antenna impedance" An article I found that's more precise: http://www.cv.nrao.edu/course/astr534/AntennaTheory.html There's a bunch of stuff later on that isn't particularly applicable to our current discussion, like the impedance of a black hole, but they do talk about reciprocity later on in the page. 73, Dan
Reply to a comment by : W6TH on 2007-02-22

. W4LGH We have been talking about transmitting antennas, I would like to know a specific purpose for using a non-resonant antenna on a transmitter. ..................................................... A long-wire antenna radiates more power in its most favorable direction than does a half wave resonant antenna in its most favorable direction. This power gain is secured at the expense of radiation in other directions. Would you like me to run some analytical Geometry for you? Maybe my math can convince you. Better yet, lets see what your math can do for me. 73, W6TH .:
Reply to a comment by : W4LGH on 2007-02-22

W6TH wrote..."This is no myth, but the truth. A resonant antenna and a non resonant antenna are both efficient antennas; non are better than the other, each has its own purpose for use." We have been talking about transmitting antennas, I would like to know a specific purpose for using a non-resonant antenna on a transmitter. If one truely understands resonance, I don't understand how anything can be as efficient as one that is resonant. And it is proven to you everytime you load up a transmitter. I certainly understand that weird things will work, but that doesn't make it so. I worked over 15 countries running 3 watts or less into a 50' wire fed at the end with an MFJ 16010 tuner. But the tuner was at the antenna feed point, matching the antenna impedance to the radio, it worked, and I certainly didn't have extra power to spare, but it would have worked BETTER, had the wire been resonant on the frequency I was using, certainly more efficient, as at resonancde the end of the wire looks like an open circuit, where as off resonance it begins to look like a short. 73 de W4LGH Alan http://www.w4lgh.com
Reply to a comment by : W6TH on 2007-02-22

. This is no myth, but the truth. A resonant antenna and a non resonant antenna are both efficient antennas; non are better than the other, each has its own purpose for use. W6TH .:
Reply to a comment by : WB2WIK on 2007-02-22

Not all solid state rigs reduce output power beginning at VSWR = 1.5. That is ultra conservative. The Ten Tec transceivers for years used a circuit breaker in the power supply to tell the transceiver when to "cut back power" due to high VSWR. They'd shut off! But until the breaker tripped, they'd keep transmitting. My Drake TR-7, by published specification, provides 90% of its full rated output power into a 2:1 VSWR and doesn't "fold back" to 50% (which is still about 75W output power) until VSWR = 5:1. That detail is listed here on the last page of the TR-7 brochure: http://wb4hfn.com/DRAKE/DrakeCatalogsBrochures/Brochure_TR7_04B.htm As such, the TR-7 hardly needs a tuner unless the user intends some pretty serious mismatches. Mine can easily produce 100W output power into a 3:1 mismatch, on any band. Without a tuner. It's largely a matter of "headroom" for the power amplifying devices selected. Margins include current, voltage and heat. One problem with a little rig like the FT-857 is its PA devices are small and its PA heatsink is *very* small, not capable of carrying much heat away from the devices, even with a fan. The TR-7 power amplifier heatsink alone (just the heatsink) is larger than the entire FT-857... WB2WIK/6
Reply to a comment by : K6HWH on 2007-02-22

"Every solidstate radio I have ever owned started shutting down power at a 1.5 swr." What about this? I have a Yaesu 857 that does indeed crank down transmit power if the SWR is the least bit off, ostensibly to prevent damage to the output transistors. If even a SWR of 5 does not diminish appreciable the antenna's ability to radiate, isn't this a mistake? Should I be looking for a way to defeat the 857's cautious approach to SWR?
Reply to a comment by : K3AN on 2007-02-22

This article is evidence that you can't determine the usefulness or accuracy of an article by the number of words. If you want useful, accurate information on antennas, please visit the L.B. Cebik web site www.cebik.com. For the last time, there is nothing magical about resonant antennas.
Reply to a comment by : N3OX on 2007-02-22

Respectfully, W4LGH, I would like to point out that you are the one muddying the waters about a *resonant antenna* and its radiating effectiveness. It is not true that antenna element resonance has anything to do with coupling power into the electromagnetic field around the antenna. The *REAL* part of the antenna impedance has two components, the radiation resistance and the loss resistance. That fraction of the power which is associated with "dissipation" in the radiation resistance is the power that gets radiated. The fraction associated with dissipation in the loss resistance goes up as heat. The power in the reactive part of the impedance is simply stored in fields around the antenna. That means that an antenna with an impedance of 70+j0 and one with an impedance of 70+j500 are radiating exactly the same amount of power if you can feed that power to them in the first place. You need to match the antenna system to the transmitter but resonance of the antenna element itself has nothing at all to do with the transfer of that power to radiating electromagnetic fields. If you are supplying 100W to the antenna, 100W minus the antenna losses is radiated, no matter whether or not the antenna element is resonant. 73, Dan
Reply to a comment by : W4LGH on 2007-02-22

You see, here we go again, a good article is written, it contains some great info. Some additional articles are written taken it a little further. Then come the people who truely do not understand what is being said, and either go on what they have seen, or what somebody else who truely doesn't understand told them. ==================================================== Now... AA4PB writes..."at resonance the antenna is inducing more power into the atmosphere ---------------------------------------------------- Can you point us to a definitive text that proves this, or even claims it to be true?" ==================================================== Now with a call like this, this guy is at least an "ADVANCED" class if not an "EXTRA" class, what I said is basic "Physics 101" Resonance is a common thread which runs through almost every branch of physics, and yet a lot of people have never studied it. Without resonance we wouldn't have radio, television, music, or swings on playgrounds, not to mention cool gismos like Tesla coils. Of course, resonance also has its dark side. It occasionally causes a bridge to collapse, a helicopter to fly apart, or other inconveniences. Unlike black holes, time travel, and quantum mechanics, resonance is common place and easy to observe. Yet, it is one of the most striking and unexpected phenomenon in all of physics. It is relative to everything. Here is a good link to read about it...hopefully it will explain.. http://www.intuitor.com/resonance/circuits.html Ever heard the term, "Dip the Plate" when tuning? Notice how the plate current drops but your output increases? Wonder why that is? Could it be your tank circuit has been tuned to resonance? Hmmm...your antenna is an extension of your tank circuit. And to K9IUQ...who wrote..."Also resonance of the SYSTEM has nothing to do with how well the antenna radiates. This is determined by MANY other factors. I have a wonderful Dummy load antenna under my desk that is resonant on all HF bands, however it doesnt seem to radiate very well since I haven't worked too many people with it."... I give up here, this guy just isn't with the program...A dummy LOAD is NOT resonate, it is a resistive LOAD designed to burn up the power by turning it into HEAT! Thats why they call it a dummy LOAD! (key word there is LOAD) Man..you guys say you want elmers, if you truely do not understand something, thats ok, there are people who do understand, and more than willing to help. 73 de W4LGH Alan http://www.w4lgh.com
Reply to a comment by : AA4PB on 2007-02-22

at resonance the antenna is inducing more power into the atmosphere ---------------------------------------------------- Can you point us to a definitive text that proves this, or even claims it to be true?
Reply to a comment by : K9IUQ on 2007-02-22

One TRUE statement was made, a RESONATE antenna will work BETTER than a NON_RESONATE antenna. People do NOT understand resonance ..................................................... The above is an false statement. An Antenna is resonant at ONLY ONE frequency. At any other frequency it is non-resonant. We all use non-resonant antennas (including you) on a daily basis. We make the antenna SYSTEM resonant with a tuner of one kind or another or live with SWR higher than 1:1. Agreed - the whole SYSTEM must be resonance -from the radio to the antenna. It makes little difference if the antenna itself is resonance or not.Many of the best performing wire antennas are non-resonant fed with open wire feeders and an antenna tuner. Also resonance of the SYSTEM has nothing to do with how well the antenna radiates. This is determined by MANY other factors. I have a wonderful Dummy load antenna under my desk that is resonant on all HF bands, however it doesnt seem to radiate very well since I haven't worked too many people with it. Please Pick Up an antenna Book like "Reflections" and learn the facts instead of trying to sell me 'some wonderful ocean front property in Arizona " K9IUQ
N6AJR2007-02-23
RE: Benchmarks
best antenna ever. a steppir, resonant on every frequency in its range.
Reply to a comment by : KE4ZHN on 2007-02-23

Ah yes, the famous "it has to be cut to the band" crap. Pure unadulterated bull**it!! Tell all the broadcast engineers at every AM broadcast station in the world and every shortwave broadcast engineer in the world that their doing it all wrong by using nonresonant antennas. And then be prepared to be made a fool of by them when they laugh in your face and explain why your full of crap. If they can stop laughing long enough to. The same way I laugh when I hear this nonsense time and time again repeated on the air. Especially when I work stations many of them cant even hear on their so called resonant antennas cut to the band. I love my 600 ohm ladderline fed 80 mtr. doublet. Since these have been around since the 20`s and 30`s I guess they just dont work at all. Its such a lousy antenna that its been around for around 80 years and yet they still dont work worth a crap. Amazing isnt it? Yeah, and those nonresonant rhombics VOA uses sure are pi$$ weak. Maybe thats why they have to run 500kw into the arrays just to make up for all those losses? lol The engineers at VOA must have to hose down the antennas and matching networks to cool the heat from the excessive losses those lousy nonresonant antennas generate. Yeah....right! Its going to take me a week to shovel all the BS out of my shack after reading some of this nonsense.
SSB2007-02-23
Benchmarks
This site is such a waste of a resource that could be very valuable if the people who control this site would get off their asses and monitor it. This thread contains SOME excellent information but the MAJORITY of stuff posted is BS. The people who could learn the most don't know what is and what isn't BS so it all becomes worthless. Too bad!


Alex....
KY1V2007-02-23
RE: No Myth

Want to know what an efficient antenna system can do in 30 minutes or less?

6Y1V DXpedition
DATE TIME MODE NUMBER FREQ CALL RCVD NEW MULTS PTS

20-Feb-07 2343 SSB 500 14207 RW0CE 59 19 19 UA9 3
20-Feb-07 2344 SSB 501 14207 DS2QEI 59 25 HL 3
20-Feb-07 2345 SSB 502 14207 JA3EY 59 25 3
20-Feb-07 2346 SSB 503 14207 JR3NZC 59 25 3
20-Feb-07 2347 SSB 504 14207 JA2FBC 59 25 3
20-Feb-07 2348 SSB 505 14207 RA0JBL 59 19 3
20-Feb-07 2349 SSB 506 14207 HL2AEJ 59 25 3
20-Feb-07 2350 SSB 507 14207 6M0MM 59 25 3
20-Feb-07 2350 SSB 508 14207 JH1OBS 59 25 3
20-Feb-07 2351 SSB 509 14207 JA1SHC 59 25 3
20-Feb-07 2351 SSB 510 14207 HL1VYF 59 25 3

20-Feb-07 2353 SSB 511 14207 HS0ZED 59 26 26 HS 3
20-Feb-07 2356 SSB 512 14207 JT1BV 59 23 23 JT 3
20-Feb-07 2357 SSB 513 14207 JA6BDB 59 25 3
20-Feb-07 2357 SSB 514 14207 DS1NMA 59 25 3
20-Feb-07 2359 SSB 515 14207 BU2AQ 59 24 24 BV 3
20-Feb-07 2359 SSB 516 14207 YB0IR 59 28 28 YB 3
21-Feb-07 0000 SSB 517 14207 HL2CFY 59 25 3
21-Feb-07 0000 SSB 518 14207 YB0QO 59 28 3
21-Feb-07 0001 SSB 519 14207 JA6VNR 59 25 3
21-Feb-07 0001 SSB 520 14207 JA0PE 59 25 3

21-Feb-07 0002 SSB 521 14207 JQ6RUP 59 25 3
21-Feb-07 0002 SSB 522 14207 RW0BG 59 18 18 3
21-Feb-07 0003 SSB 523 14207 JT1KAI 59 23 3
21-Feb-07 0003 SSB 524 14207 JA8MS 59 25 3
21-Feb-07 0004 SSB 525 14207 HL1SRJ 59 25 3
21-Feb-07 0005 SSB 526 14207 JA1BWD 59 25 3
21-Feb-07 0005 SSB 527 14207 JM1HJG 59 25 3
21-Feb-07 0005 SSB 528 14207 JA7GY 59 25 3
21-Feb-07 0006 SSB 529 14207 JA8SM 59 25 3
21-Feb-07 0007 SSB 530 14207 JA8EC 59 25 3

21-Feb-07 0008 SSB 531 14207 JF0EHX 59 25 3
21-Feb-07 0009 SSB 532 14207 JN1ZME 59 25 3
21-Feb-07 0010 SSB 533 14207 DU1HBC 59 27 27 DU 3
21-Feb-07 0011 SSB 534 14207 JM7EPG 59 25 3
21-Feb-07 0012 SSB 535 14207 JA0AVS 59 25 3

The JT1's were peaking 10db over S9.

WWW.6Y1V.COM

David ~ KY1V / 6Y1V
Reply to a comment by : KA0GKT on 2007-02-23

W8WZ wrote: "Some Good points are made here - but one that is over looked in the article is that an antenna does NOT have to be resonant to have positive gain. Classic wire designs such as the Zepp, Extended Double Zepp, and Sterba Curtain are not resonant and will need to have some sort of antenna coupler to be used with a transmitter that is looking for a 50 ohm match. Nevertheless, when matched to the Xmtr with the transmatch - they work very well and exhibit high amounts of gain. " ============= Actually, the Zepp is a resonant antenna it is an end-fed halfwave antenna. It is a high impedance antenna, however it is indeed resonant. IIRC, the curtain sterba is also a resoanat antenna as the lengths of each section of the antena are multiples of 1/4-wavelength. A good example of a non-resonant antenna with high gain would be the non-resonant or terminated Rhombic antenna; an example of a non-resonant antenna with little gain would be a windom (the original not the 'Carolina' antenna which wasn't designed by Laurent G. Windom and described in QST sometime in '29). 73 DE KAØGKT/7 --Steve
Reply to a comment by : W8WZ on 2007-02-23

Some Good points are made here - but one that is over looked in the article is that an antenna does NOT have to be resonant to have positive gain. Classic wire designs such as the Zepp, Extended Double Zepp, and Sterba Curtain are not resonant and will need to have some sort of antenna coupler to be used with a transmitter that is looking for a 50 ohm match. Nevertheless, when matched to the Xmtr with the transmatch - they work very well and exhibit high amounts of gain. Other antennas like the Fritzel will be technically resonant on many frequencys but with little or no gain. Also - in Amateur practice whener DB is used it is assumed that it is DBd - at least according to the handbook.
Reply to a comment by : W4LGH on 2007-02-22

W6TH Vito wrote.. ~"W4LGH Alan, I've heard enough of your bullshit, enough is enough."~ Well Mr Vito...That certainly was an educated response! I have seen it all in my career, from a 5 gallon bucket of dirt in a guys trunk, because the instructions said "This wire needs to go to EARTH ground", to a station engineer who wouldn't let anyone install any antennas upside down on his tower because he said, RF would leak out. I guess some people take things to litteral, and some don't take it litteral enough. A lot of good info in this thread, but again it goes to show you can not POST a good article here on eHam, no matter what, people will try to tear it apart. No one understands friendly debate. 73 de W4LGH - Alan
Reply to a comment by : W6TH on 2007-02-22

. W4LGH Alan, I've heard enough of your bullshit, enough is enough. W6TH .:
Reply to a comment by : W6TH on 2007-02-22

. Frequency = 1 divided by time. Time is relevant. Known as the Black Hole. No Myth. .:
Reply to a comment by : N3OX on 2007-02-22

"But the tuner was at the antenna feed point, matching the antenna impedance to the radio, it worked, and I certainly didn't have extra power to spare, but it would have worked BETTER, had the wire been resonant on the frequency I was using" Untrue.
Reply to a comment by : N3OX on 2007-02-22

W4LGH: The excerpt you quoted from that page explains that a center fed antenna has the lowest possible impedance when it's half-wave resonant (or three-halves or five halves, whatever); that is, if you fix the ***voltage*** you feed to an antenna, you'll get the most current, and therefore the biggest field, when it's an odd multiple of a half wave. If you force the same current in a similar, but nonresonant antenna, you get the same strength field (up to the antenna being a little bit shorter or longer which affects its gain in a minor fashion). If you had a magical transistor or tube that didn't care if the voltage was not in phase with the current and didn't care how high that voltage got, you would never have to match to a nonresonant antenna. We always say that we're "transforming the antenna impedance" with a network, but we could equally say "we're transforming the transmitter output up to a voltage with the proper phase to drive the a particular current into the antenna impedance" An article I found that's more precise: http://www.cv.nrao.edu/course/astr534/AntennaTheory.html There's a bunch of stuff later on that isn't particularly applicable to our current discussion, like the impedance of a black hole, but they do talk about reciprocity later on in the page. 73, Dan
Reply to a comment by : W6TH on 2007-02-22

. W4LGH We have been talking about transmitting antennas, I would like to know a specific purpose for using a non-resonant antenna on a transmitter. ..................................................... A long-wire antenna radiates more power in its most favorable direction than does a half wave resonant antenna in its most favorable direction. This power gain is secured at the expense of radiation in other directions. Would you like me to run some analytical Geometry for you? Maybe my math can convince you. Better yet, lets see what your math can do for me. 73, W6TH .:
Reply to a comment by : W4LGH on 2007-02-22

W6TH wrote..."This is no myth, but the truth. A resonant antenna and a non resonant antenna are both efficient antennas; non are better than the other, each has its own purpose for use." We have been talking about transmitting antennas, I would like to know a specific purpose for using a non-resonant antenna on a transmitter. If one truely understands resonance, I don't understand how anything can be as efficient as one that is resonant. And it is proven to you everytime you load up a transmitter. I certainly understand that weird things will work, but that doesn't make it so. I worked over 15 countries running 3 watts or less into a 50' wire fed at the end with an MFJ 16010 tuner. But the tuner was at the antenna feed point, matching the antenna impedance to the radio, it worked, and I certainly didn't have extra power to spare, but it would have worked BETTER, had the wire been resonant on the frequency I was using, certainly more efficient, as at resonancde the end of the wire looks like an open circuit, where as off resonance it begins to look like a short. 73 de W4LGH Alan http://www.w4lgh.com
Reply to a comment by : W6TH on 2007-02-22

. This is no myth, but the truth. A resonant antenna and a non resonant antenna are both efficient antennas; non are better than the other, each has its own purpose for use. W6TH .:
Reply to a comment by : WB2WIK on 2007-02-22

Not all solid state rigs reduce output power beginning at VSWR = 1.5. That is ultra conservative. The Ten Tec transceivers for years used a circuit breaker in the power supply to tell the transceiver when to "cut back power" due to high VSWR. They'd shut off! But until the breaker tripped, they'd keep transmitting. My Drake TR-7, by published specification, provides 90% of its full rated output power into a 2:1 VSWR and doesn't "fold back" to 50% (which is still about 75W output power) until VSWR = 5:1. That detail is listed here on the last page of the TR-7 brochure: http://wb4hfn.com/DRAKE/DrakeCatalogsBrochures/Brochure_TR7_04B.htm As such, the TR-7 hardly needs a tuner unless the user intends some pretty serious mismatches. Mine can easily produce 100W output power into a 3:1 mismatch, on any band. Without a tuner. It's largely a matter of "headroom" for the power amplifying devices selected. Margins include current, voltage and heat. One problem with a little rig like the FT-857 is its PA devices are small and its PA heatsink is *very* small, not capable of carrying much heat away from the devices, even with a fan. The TR-7 power amplifier heatsink alone (just the heatsink) is larger than the entire FT-857... WB2WIK/6
Reply to a comment by : K6HWH on 2007-02-22

"Every solidstate radio I have ever owned started shutting down power at a 1.5 swr." What about this? I have a Yaesu 857 that does indeed crank down transmit power if the SWR is the least bit off, ostensibly to prevent damage to the output transistors. If even a SWR of 5 does not diminish appreciable the antenna's ability to radiate, isn't this a mistake? Should I be looking for a way to defeat the 857's cautious approach to SWR?
Reply to a comment by : K3AN on 2007-02-22

This article is evidence that you can't determine the usefulness or accuracy of an article by the number of words. If you want useful, accurate information on antennas, please visit the L.B. Cebik web site www.cebik.com. For the last time, there is nothing magical about resonant antennas.
Reply to a comment by : N3OX on 2007-02-22

Respectfully, W4LGH, I would like to point out that you are the one muddying the waters about a *resonant antenna* and its radiating effectiveness. It is not true that antenna element resonance has anything to do with coupling power into the electromagnetic field around the antenna. The *REAL* part of the antenna impedance has two components, the radiation resistance and the loss resistance. That fraction of the power which is associated with "dissipation" in the radiation resistance is the power that gets radiated. The fraction associated with dissipation in the loss resistance goes up as heat. The power in the reactive part of the impedance is simply stored in fields around the antenna. That means that an antenna with an impedance of 70+j0 and one with an impedance of 70+j500 are radiating exactly the same amount of power if you can feed that power to them in the first place. You need to match the antenna system to the transmitter but resonance of the antenna element itself has nothing at all to do with the transfer of that power to radiating electromagnetic fields. If you are supplying 100W to the antenna, 100W minus the antenna losses is radiated, no matter whether or not the antenna element is resonant. 73, Dan
Reply to a comment by : W4LGH on 2007-02-22

You see, here we go again, a good article is written, it contains some great info. Some additional articles are written taken it a little further. Then come the people who truely do not understand what is being said, and either go on what they have seen, or what somebody else who truely doesn't understand told them. ==================================================== Now... AA4PB writes..."at resonance the antenna is inducing more power into the atmosphere ---------------------------------------------------- Can you point us to a definitive text that proves this, or even claims it to be true?" ==================================================== Now with a call like this, this guy is at least an "ADVANCED" class if not an "EXTRA" class, what I said is basic "Physics 101" Resonance is a common thread which runs through almost every branch of physics, and yet a lot of people have never studied it. Without resonance we wouldn't have radio, television, music, or swings on playgrounds, not to mention cool gismos like Tesla coils. Of course, resonance also has its dark side. It occasionally causes a bridge to collapse, a helicopter to fly apart, or other inconveniences. Unlike black holes, time travel, and quantum mechanics, resonance is common place and easy to observe. Yet, it is one of the most striking and unexpected phenomenon in all of physics. It is relative to everything. Here is a good link to read about it...hopefully it will explain.. http://www.intuitor.com/resonance/circuits.html Ever heard the term, "Dip the Plate" when tuning? Notice how the plate current drops but your output increases? Wonder why that is? Could it be your tank circuit has been tuned to resonance? Hmmm...your antenna is an extension of your tank circuit. And to K9IUQ...who wrote..."Also resonance of the SYSTEM has nothing to do with how well the antenna radiates. This is determined by MANY other factors. I have a wonderful Dummy load antenna under my desk that is resonant on all HF bands, however it doesnt seem to radiate very well since I haven't worked too many people with it."... I give up here, this guy just isn't with the program...A dummy LOAD is NOT resonate, it is a resistive LOAD designed to burn up the power by turning it into HEAT! Thats why they call it a dummy LOAD! (key word there is LOAD) Man..you guys say you want elmers, if you truely do not understand something, thats ok, there are people who do understand, and more than willing to help. 73 de W4LGH Alan http://www.w4lgh.com
Reply to a comment by : AA4PB on 2007-02-22

at resonance the antenna is inducing more power into the atmosphere ---------------------------------------------------- Can you point us to a definitive text that proves this, or even claims it to be true?
Reply to a comment by : K9IUQ on 2007-02-22

One TRUE statement was made, a RESONATE antenna will work BETTER than a NON_RESONATE antenna. People do NOT understand resonance ..................................................... The above is an false statement. An Antenna is resonant at ONLY ONE frequency. At any other frequency it is non-resonant. We all use non-resonant antennas (including you) on a daily basis. We make the antenna SYSTEM resonant with a tuner of one kind or another or live with SWR higher than 1:1. Agreed - the whole SYSTEM must be resonance -from the radio to the antenna. It makes little difference if the antenna itself is resonance or not.Many of the best performing wire antennas are non-resonant fed with open wire feeders and an antenna tuner. Also resonance of the SYSTEM has nothing to do with how well the antenna radiates. This is determined by MANY other factors. I have a wonderful Dummy load antenna under my desk that is resonant on all HF bands, however it doesnt seem to radiate very well since I haven't worked too many people with it. Please Pick Up an antenna Book like "Reflections" and learn the facts instead of trying to sell me 'some wonderful ocean front property in Arizona " K9IUQ
W4LGH2007-02-23
RE: No Myth
W8WZ wrote:
"Some Good points are made here - but one that is over looked in the article is that an antenna does NOT have to be resonant to have positive gain.

Classic wire designs such as the Zepp, Extended Double Zepp, and Sterba Curtain are not resonant and will need to have some sort of antenna coupler to be used with a transmitter that is looking for a 50 ohm match. Nevertheless, when matched to the Xmtr with the transmatch - they work very well and exhibit high amounts of gain. "

------------------------

Actually, the Zepp is a resonant antenna it is an end-fed halfwave antenna. It is a high impedance antenna, however it is indeed resonant. IIRC, the curtain sterba is also a resoanat antenna as the lengths of each section of the antena are multiples of 1/4-wavelength. A good example of a non-resonant antenna with high gain would be the non-resonant or terminated Rhombic antenna; an example of a non-resonant antenna with little gain would be a windom (the original not the 'Carolina' antenna which wasn't designed by Laurent G. Windom and described in QST sometime in '29).

73 DE KAØGKT/7

===================================

I am slowly begining to think that people are thinking that a resonant antenna has to be 50 ohms. And that is not the case, nor what I mean when I say resonant! Actually a cut to frequency flat-top dipole is closer to 72ohms than 50. Dropping the ends in an inverted V will lower this a tad, as well as change the angle of radiation. When I say that an antenna is most efficient at resonance, I am saying the wire is cut to some multiple of the main frequency, 1/4wave, 1/2wave, fullwave etc. being resonate has nothing to do with the feed impedance or an SWR match.

73 de W4LGH - Alan
http://www.w4lgh.com

Reply to a comment by : KA0GKT on 2007-02-23

W8WZ wrote: "Some Good points are made here - but one that is over looked in the article is that an antenna does NOT have to be resonant to have positive gain. Classic wire designs such as the Zepp, Extended Double Zepp, and Sterba Curtain are not resonant and will need to have some sort of antenna coupler to be used with a transmitter that is looking for a 50 ohm match. Nevertheless, when matched to the Xmtr with the transmatch - they work very well and exhibit high amounts of gain. " ============= Actually, the Zepp is a resonant antenna it is an end-fed halfwave antenna. It is a high impedance antenna, however it is indeed resonant. IIRC, the curtain sterba is also a resoanat antenna as the lengths of each section of the antena are multiples of 1/4-wavelength. A good example of a non-resonant antenna with high gain would be the non-resonant or terminated Rhombic antenna; an example of a non-resonant antenna with little gain would be a windom (the original not the 'Carolina' antenna which wasn't designed by Laurent G. Windom and described in QST sometime in '29). 73 DE KAØGKT/7 --Steve
Reply to a comment by : W8WZ on 2007-02-23

Some Good points are made here - but one that is over looked in the article is that an antenna does NOT have to be resonant to have positive gain. Classic wire designs such as the Zepp, Extended Double Zepp, and Sterba Curtain are not resonant and will need to have some sort of antenna coupler to be used with a transmitter that is looking for a 50 ohm match. Nevertheless, when matched to the Xmtr with the transmatch - they work very well and exhibit high amounts of gain. Other antennas like the Fritzel will be technically resonant on many frequencys but with little or no gain. Also - in Amateur practice whener DB is used it is assumed that it is DBd - at least according to the handbook.
Reply to a comment by : W4LGH on 2007-02-22

W6TH Vito wrote.. ~"W4LGH Alan, I've heard enough of your bullshit, enough is enough."~ Well Mr Vito...That certainly was an educated response! I have seen it all in my career, from a 5 gallon bucket of dirt in a guys trunk, because the instructions said "This wire needs to go to EARTH ground", to a station engineer who wouldn't let anyone install any antennas upside down on his tower because he said, RF would leak out. I guess some people take things to litteral, and some don't take it litteral enough. A lot of good info in this thread, but again it goes to show you can not POST a good article here on eHam, no matter what, people will try to tear it apart. No one understands friendly debate. 73 de W4LGH - Alan
Reply to a comment by : W6TH on 2007-02-22

. W4LGH Alan, I've heard enough of your bullshit, enough is enough. W6TH .:
Reply to a comment by : W6TH on 2007-02-22

. Frequency = 1 divided by time. Time is relevant. Known as the Black Hole. No Myth. .:
Reply to a comment by : N3OX on 2007-02-22

"But the tuner was at the antenna feed point, matching the antenna impedance to the radio, it worked, and I certainly didn't have extra power to spare, but it would have worked BETTER, had the wire been resonant on the frequency I was using" Untrue.
Reply to a comment by : N3OX on 2007-02-22

W4LGH: The excerpt you quoted from that page explains that a center fed antenna has the lowest possible impedance when it's half-wave resonant (or three-halves or five halves, whatever); that is, if you fix the ***voltage*** you feed to an antenna, you'll get the most current, and therefore the biggest field, when it's an odd multiple of a half wave. If you force the same current in a similar, but nonresonant antenna, you get the same strength field (up to the antenna being a little bit shorter or longer which affects its gain in a minor fashion). If you had a magical transistor or tube that didn't care if the voltage was not in phase with the current and didn't care how high that voltage got, you would never have to match to a nonresonant antenna. We always say that we're "transforming the antenna impedance" with a network, but we could equally say "we're transforming the transmitter output up to a voltage with the proper phase to drive the a particular current into the antenna impedance" An article I found that's more precise: http://www.cv.nrao.edu/course/astr534/AntennaTheory.html There's a bunch of stuff later on that isn't particularly applicable to our current discussion, like the impedance of a black hole, but they do talk about reciprocity later on in the page. 73, Dan
Reply to a comment by : W6TH on 2007-02-22

. W4LGH We have been talking about transmitting antennas, I would like to know a specific purpose for using a non-resonant antenna on a transmitter. ..................................................... A long-wire antenna radiates more power in its most favorable direction than does a half wave resonant antenna in its most favorable direction. This power gain is secured at the expense of radiation in other directions. Would you like me to run some analytical Geometry for you? Maybe my math can convince you. Better yet, lets see what your math can do for me. 73, W6TH .:
Reply to a comment by : W4LGH on 2007-02-22

W6TH wrote..."This is no myth, but the truth. A resonant antenna and a non resonant antenna are both efficient antennas; non are better than the other, each has its own purpose for use." We have been talking about transmitting antennas, I would like to know a specific purpose for using a non-resonant antenna on a transmitter. If one truely understands resonance, I don't understand how anything can be as efficient as one that is resonant. And it is proven to you everytime you load up a transmitter. I certainly understand that weird things will work, but that doesn't make it so. I worked over 15 countries running 3 watts or less into a 50' wire fed at the end with an MFJ 16010 tuner. But the tuner was at the antenna feed point, matching the antenna impedance to the radio, it worked, and I certainly didn't have extra power to spare, but it would have worked BETTER, had the wire been resonant on the frequency I was using, certainly more efficient, as at resonancde the end of the wire looks like an open circuit, where as off resonance it begins to look like a short. 73 de W4LGH Alan http://www.w4lgh.com
Reply to a comment by : W6TH on 2007-02-22

. This is no myth, but the truth. A resonant antenna and a non resonant antenna are both efficient antennas; non are better than the other, each has its own purpose for use. W6TH .:
Reply to a comment by : WB2WIK on 2007-02-22

Not all solid state rigs reduce output power beginning at VSWR = 1.5. That is ultra conservative. The Ten Tec transceivers for years used a circuit breaker in the power supply to tell the transceiver when to "cut back power" due to high VSWR. They'd shut off! But until the breaker tripped, they'd keep transmitting. My Drake TR-7, by published specification, provides 90% of its full rated output power into a 2:1 VSWR and doesn't "fold back" to 50% (which is still about 75W output power) until VSWR = 5:1. That detail is listed here on the last page of the TR-7 brochure: http://wb4hfn.com/DRAKE/DrakeCatalogsBrochures/Brochure_TR7_04B.htm As such, the TR-7 hardly needs a tuner unless the user intends some pretty serious mismatches. Mine can easily produce 100W output power into a 3:1 mismatch, on any band. Without a tuner. It's largely a matter of "headroom" for the power amplifying devices selected. Margins include current, voltage and heat. One problem with a little rig like the FT-857 is its PA devices are small and its PA heatsink is *very* small, not capable of carrying much heat away from the devices, even with a fan. The TR-7 power amplifier heatsink alone (just the heatsink) is larger than the entire FT-857... WB2WIK/6
Reply to a comment by : K6HWH on 2007-02-22

"Every solidstate radio I have ever owned started shutting down power at a 1.5 swr." What about this? I have a Yaesu 857 that does indeed crank down transmit power if the SWR is the least bit off, ostensibly to prevent damage to the output transistors. If even a SWR of 5 does not diminish appreciable the antenna's ability to radiate, isn't this a mistake? Should I be looking for a way to defeat the 857's cautious approach to SWR?
Reply to a comment by : K3AN on 2007-02-22

This article is evidence that you can't determine the usefulness or accuracy of an article by the number of words. If you want useful, accurate information on antennas, please visit the L.B. Cebik web site www.cebik.com. For the last time, there is nothing magical about resonant antennas.
Reply to a comment by : N3OX on 2007-02-22

Respectfully, W4LGH, I would like to point out that you are the one muddying the waters about a *resonant antenna* and its radiating effectiveness. It is not true that antenna element resonance has anything to do with coupling power into the electromagnetic field around the antenna. The *REAL* part of the antenna impedance has two components, the radiation resistance and the loss resistance. That fraction of the power which is associated with "dissipation" in the radiation resistance is the power that gets radiated. The fraction associated with dissipation in the loss resistance goes up as heat. The power in the reactive part of the impedance is simply stored in fields around the antenna. That means that an antenna with an impedance of 70+j0 and one with an impedance of 70+j500 are radiating exactly the same amount of power if you can feed that power to them in the first place. You need to match the antenna system to the transmitter but resonance of the antenna element itself has nothing at all to do with the transfer of that power to radiating electromagnetic fields. If you are supplying 100W to the antenna, 100W minus the antenna losses is radiated, no matter whether or not the antenna element is resonant. 73, Dan
Reply to a comment by : W4LGH on 2007-02-22

You see, here we go again, a good article is written, it contains some great info. Some additional articles are written taken it a little further. Then come the people who truely do not understand what is being said, and either go on what they have seen, or what somebody else who truely doesn't understand told them. ==================================================== Now... AA4PB writes..."at resonance the antenna is inducing more power into the atmosphere ---------------------------------------------------- Can you point us to a definitive text that proves this, or even claims it to be true?" ==================================================== Now with a call like this, this guy is at least an "ADVANCED" class if not an "EXTRA" class, what I said is basic "Physics 101" Resonance is a common thread which runs through almost every branch of physics, and yet a lot of people have never studied it. Without resonance we wouldn't have radio, television, music, or swings on playgrounds, not to mention cool gismos like Tesla coils. Of course, resonance also has its dark side. It occasionally causes a bridge to collapse, a helicopter to fly apart, or other inconveniences. Unlike black holes, time travel, and quantum mechanics, resonance is common place and easy to observe. Yet, it is one of the most striking and unexpected phenomenon in all of physics. It is relative to everything. Here is a good link to read about it...hopefully it will explain.. http://www.intuitor.com/resonance/circuits.html Ever heard the term, "Dip the Plate" when tuning? Notice how the plate current drops but your output increases? Wonder why that is? Could it be your tank circuit has been tuned to resonance? Hmmm...your antenna is an extension of your tank circuit. And to K9IUQ...who wrote..."Also resonance of the SYSTEM has nothing to do with how well the antenna radiates. This is determined by MANY other factors. I have a wonderful Dummy load antenna under my desk that is resonant on all HF bands, however it doesnt seem to radiate very well since I haven't worked too many people with it."... I give up here, this guy just isn't with the program...A dummy LOAD is NOT resonate, it is a resistive LOAD designed to burn up the power by turning it into HEAT! Thats why they call it a dummy LOAD! (key word there is LOAD) Man..you guys say you want elmers, if you truely do not understand something, thats ok, there are people who do understand, and more than willing to help. 73 de W4LGH Alan http://www.w4lgh.com
Reply to a comment by : AA4PB on 2007-02-22

at resonance the antenna is inducing more power into the atmosphere ---------------------------------------------------- Can you point us to a definitive text that proves this, or even claims it to be true?
Reply to a comment by : K9IUQ on 2007-02-22

One TRUE statement was made, a RESONATE antenna will work BETTER than a NON_RESONATE antenna. People do NOT understand resonance ..................................................... The above is an false statement. An Antenna is resonant at ONLY ONE frequency. At any other frequency it is non-resonant. We all use non-resonant antennas (including you) on a daily basis. We make the antenna SYSTEM resonant with a tuner of one kind or another or live with SWR higher than 1:1. Agreed - the whole SYSTEM must be resonance -from the radio to the antenna. It makes little difference if the antenna itself is resonance or not.Many of the best performing wire antennas are non-resonant fed with open wire feeders and an antenna tuner. Also resonance of the SYSTEM has nothing to do with how well the antenna radiates. This is determined by MANY other factors. I have a wonderful Dummy load antenna under my desk that is resonant on all HF bands, however it doesnt seem to radiate very well since I haven't worked too many people with it. Please Pick Up an antenna Book like "Reflections" and learn the facts instead of trying to sell me 'some wonderful ocean front property in Arizona " K9IUQ
N8BOA2007-02-23
RE: No Myth
I have a dummy load that has perfect SWR across the entire band and I can work everything that I can hear.
Therfore it is a perfect antenna
Reply to a comment by : KA0GKT on 2007-02-23

W8WZ wrote: "Some Good points are made here - but one that is over looked in the article is that an antenna does NOT have to be resonant to have positive gain. Classic wire designs such as the Zepp, Extended Double Zepp, and Sterba Curtain are not resonant and will need to have some sort of antenna coupler to be used with a transmitter that is looking for a 50 ohm match. Nevertheless, when matched to the Xmtr with the transmatch - they work very well and exhibit high amounts of gain. " ============= Actually, the Zepp is a resonant antenna it is an end-fed halfwave antenna. It is a high impedance antenna, however it is indeed resonant. IIRC, the curtain sterba is also a resoanat antenna as the lengths of each section of the antena are multiples of 1/4-wavelength. A good example of a non-resonant antenna with high gain would be the non-resonant or terminated Rhombic antenna; an example of a non-resonant antenna with little gain would be a windom (the original not the 'Carolina' antenna which wasn't designed by Laurent G. Windom and described in QST sometime in '29). 73 DE KAØGKT/7 --Steve
Reply to a comment by : W8WZ on 2007-02-23

Some Good points are made here - but one that is over looked in the article is that an antenna does NOT have to be resonant to have positive gain. Classic wire designs such as the Zepp, Extended Double Zepp, and Sterba Curtain are not resonant and will need to have some sort of antenna coupler to be used with a transmitter that is looking for a 50 ohm match. Nevertheless, when matched to the Xmtr with the transmatch - they work very well and exhibit high amounts of gain. Other antennas like the Fritzel will be technically resonant on many frequencys but with little or no gain. Also - in Amateur practice whener DB is used it is assumed that it is DBd - at least according to the handbook.
Reply to a comment by : W4LGH on 2007-02-22

W6TH Vito wrote.. ~"W4LGH Alan, I've heard enough of your bullshit, enough is enough."~ Well Mr Vito...That certainly was an educated response! I have seen it all in my career, from a 5 gallon bucket of dirt in a guys trunk, because the instructions said "This wire needs to go to EARTH ground", to a station engineer who wouldn't let anyone install any antennas upside down on his tower because he said, RF would leak out. I guess some people take things to litteral, and some don't take it litteral enough. A lot of good info in this thread, but again it goes to show you can not POST a good article here on eHam, no matter what, people will try to tear it apart. No one understands friendly debate. 73 de W4LGH - Alan
Reply to a comment by : W6TH on 2007-02-22

. W4LGH Alan, I've heard enough of your bullshit, enough is enough. W6TH .:
Reply to a comment by : W6TH on 2007-02-22

. Frequency = 1 divided by time. Time is relevant. Known as the Black Hole. No Myth. .:
Reply to a comment by : N3OX on 2007-02-22

"But the tuner was at the antenna feed point, matching the antenna impedance to the radio, it worked, and I certainly didn't have extra power to spare, but it would have worked BETTER, had the wire been resonant on the frequency I was using" Untrue.
Reply to a comment by : N3OX on 2007-02-22

W4LGH: The excerpt you quoted from that page explains that a center fed antenna has the lowest possible impedance when it's half-wave resonant (or three-halves or five halves, whatever); that is, if you fix the ***voltage*** you feed to an antenna, you'll get the most current, and therefore the biggest field, when it's an odd multiple of a half wave. If you force the same current in a similar, but nonresonant antenna, you get the same strength field (up to the antenna being a little bit shorter or longer which affects its gain in a minor fashion). If you had a magical transistor or tube that didn't care if the voltage was not in phase with the current and didn't care how high that voltage got, you would never have to match to a nonresonant antenna. We always say that we're "transforming the antenna impedance" with a network, but we could equally say "we're transforming the transmitter output up to a voltage with the proper phase to drive the a particular current into the antenna impedance" An article I found that's more precise: http://www.cv.nrao.edu/course/astr534/AntennaTheory.html There's a bunch of stuff later on that isn't particularly applicable to our current discussion, like the impedance of a black hole, but they do talk about reciprocity later on in the page. 73, Dan
Reply to a comment by : W6TH on 2007-02-22

. W4LGH We have been talking about transmitting antennas, I would like to know a specific purpose for using a non-resonant antenna on a transmitter. ..................................................... A long-wire antenna radiates more power in its most favorable direction than does a half wave resonant antenna in its most favorable direction. This power gain is secured at the expense of radiation in other directions. Would you like me to run some analytical Geometry for you? Maybe my math can convince you. Better yet, lets see what your math can do for me. 73, W6TH .:
Reply to a comment by : W4LGH on 2007-02-22

W6TH wrote..."This is no myth, but the truth. A resonant antenna and a non resonant antenna are both efficient antennas; non are better than the other, each has its own purpose for use." We have been talking about transmitting antennas, I would like to know a specific purpose for using a non-resonant antenna on a transmitter. If one truely understands resonance, I don't understand how anything can be as efficient as one that is resonant. And it is proven to you everytime you load up a transmitter. I certainly understand that weird things will work, but that doesn't make it so. I worked over 15 countries running 3 watts or less into a 50' wire fed at the end with an MFJ 16010 tuner. But the tuner was at the antenna feed point, matching the antenna impedance to the radio, it worked, and I certainly didn't have extra power to spare, but it would have worked BETTER, had the wire been resonant on the frequency I was using, certainly more efficient, as at resonancde the end of the wire looks like an open circuit, where as off resonance it begins to look like a short. 73 de W4LGH Alan http://www.w4lgh.com
Reply to a comment by : W6TH on 2007-02-22

. This is no myth, but the truth. A resonant antenna and a non resonant antenna are both efficient antennas; non are better than the other, each has its own purpose for use. W6TH .:
Reply to a comment by : WB2WIK on 2007-02-22

Not all solid state rigs reduce output power beginning at VSWR = 1.5. That is ultra conservative. The Ten Tec transceivers for years used a circuit breaker in the power supply to tell the transceiver when to "cut back power" due to high VSWR. They'd shut off! But until the breaker tripped, they'd keep transmitting. My Drake TR-7, by published specification, provides 90% of its full rated output power into a 2:1 VSWR and doesn't "fold back" to 50% (which is still about 75W output power) until VSWR = 5:1. That detail is listed here on the last page of the TR-7 brochure: http://wb4hfn.com/DRAKE/DrakeCatalogsBrochures/Brochure_TR7_04B.htm As such, the TR-7 hardly needs a tuner unless the user intends some pretty serious mismatches. Mine can easily produce 100W output power into a 3:1 mismatch, on any band. Without a tuner. It's largely a matter of "headroom" for the power amplifying devices selected. Margins include current, voltage and heat. One problem with a little rig like the FT-857 is its PA devices are small and its PA heatsink is *very* small, not capable of carrying much heat away from the devices, even with a fan. The TR-7 power amplifier heatsink alone (just the heatsink) is larger than the entire FT-857... WB2WIK/6
Reply to a comment by : K6HWH on 2007-02-22

"Every solidstate radio I have ever owned started shutting down power at a 1.5 swr." What about this? I have a Yaesu 857 that does indeed crank down transmit power if the SWR is the least bit off, ostensibly to prevent damage to the output transistors. If even a SWR of 5 does not diminish appreciable the antenna's ability to radiate, isn't this a mistake? Should I be looking for a way to defeat the 857's cautious approach to SWR?
Reply to a comment by : K3AN on 2007-02-22

This article is evidence that you can't determine the usefulness or accuracy of an article by the number of words. If you want useful, accurate information on antennas, please visit the L.B. Cebik web site www.cebik.com. For the last time, there is nothing magical about resonant antennas.
Reply to a comment by : N3OX on 2007-02-22

Respectfully, W4LGH, I would like to point out that you are the one muddying the waters about a *resonant antenna* and its radiating effectiveness. It is not true that antenna element resonance has anything to do with coupling power into the electromagnetic field around the antenna. The *REAL* part of the antenna impedance has two components, the radiation resistance and the loss resistance. That fraction of the power which is associated with "dissipation" in the radiation resistance is the power that gets radiated. The fraction associated with dissipation in the loss resistance goes up as heat. The power in the reactive part of the impedance is simply stored in fields around the antenna. That means that an antenna with an impedance of 70+j0 and one with an impedance of 70+j500 are radiating exactly the same amount of power if you can feed that power to them in the first place. You need to match the antenna system to the transmitter but resonance of the antenna element itself has nothing at all to do with the transfer of that power to radiating electromagnetic fields. If you are supplying 100W to the antenna, 100W minus the antenna losses is radiated, no matter whether or not the antenna element is resonant. 73, Dan
Reply to a comment by : W4LGH on 2007-02-22

You see, here we go again, a good article is written, it contains some great info. Some additional articles are written taken it a little further. Then come the people who truely do not understand what is being said, and either go on what they have seen, or what somebody else who truely doesn't understand told them. ==================================================== Now... AA4PB writes..."at resonance the antenna is inducing more power into the atmosphere ---------------------------------------------------- Can you point us to a definitive text that proves this, or even claims it to be true?" ==================================================== Now with a call like this, this guy is at least an "ADVANCED" class if not an "EXTRA" class, what I said is basic "Physics 101" Resonance is a common thread which runs through almost every branch of physics, and yet a lot of people have never studied it. Without resonance we wouldn't have radio, television, music, or swings on playgrounds, not to mention cool gismos like Tesla coils. Of course, resonance also has its dark side. It occasionally causes a bridge to collapse, a helicopter to fly apart, or other inconveniences. Unlike black holes, time travel, and quantum mechanics, resonance is common place and easy to observe. Yet, it is one of the most striking and unexpected phenomenon in all of physics. It is relative to everything. Here is a good link to read about it...hopefully it will explain.. http://www.intuitor.com/resonance/circuits.html Ever heard the term, "Dip the Plate" when tuning? Notice how the plate current drops but your output increases? Wonder why that is? Could it be your tank circuit has been tuned to resonance? Hmmm...your antenna is an extension of your tank circuit. And to K9IUQ...who wrote..."Also resonance of the SYSTEM has nothing to do with how well the antenna radiates. This is determined by MANY other factors. I have a wonderful Dummy load antenna under my desk that is resonant on all HF bands, however it doesnt seem to radiate very well since I haven't worked too many people with it."... I give up here, this guy just isn't with the program...A dummy LOAD is NOT resonate, it is a resistive LOAD designed to burn up the power by turning it into HEAT! Thats why they call it a dummy LOAD! (key word there is LOAD) Man..you guys say you want elmers, if you truely do not understand something, thats ok, there are people who do understand, and more than willing to help. 73 de W4LGH Alan http://www.w4lgh.com
Reply to a comment by : AA4PB on 2007-02-22

at resonance the antenna is inducing more power into the atmosphere ---------------------------------------------------- Can you point us to a definitive text that proves this, or even claims it to be true?
Reply to a comment by : K9IUQ on 2007-02-22

One TRUE statement was made, a RESONATE antenna will work BETTER than a NON_RESONATE antenna. People do NOT understand resonance ..................................................... The above is an false statement. An Antenna is resonant at ONLY ONE frequency. At any other frequency it is non-resonant. We all use non-resonant antennas (including you) on a daily basis. We make the antenna SYSTEM resonant with a tuner of one kind or another or live with SWR higher than 1:1. Agreed - the whole SYSTEM must be resonance -from the radio to the antenna. It makes little difference if the antenna itself is resonance or not.Many of the best performing wire antennas are non-resonant fed with open wire feeders and an antenna tuner. Also resonance of the SYSTEM has nothing to do with how well the antenna radiates. This is determined by MANY other factors. I have a wonderful Dummy load antenna under my desk that is resonant on all HF bands, however it doesnt seem to radiate very well since I haven't worked too many people with it. Please Pick Up an antenna Book like "Reflections" and learn the facts instead of trying to sell me 'some wonderful ocean front property in Arizona " K9IUQ
KA0GKT2007-02-23
RE: No Myth
W8WZ wrote:
"Some Good points are made here - but one that is over looked in the article is that an antenna does NOT have to be resonant to have positive gain.

Classic wire designs such as the Zepp, Extended Double Zepp, and Sterba Curtain are not resonant and will need to have some sort of antenna coupler to be used with a transmitter that is looking for a 50 ohm match. Nevertheless, when matched to the Xmtr with the transmatch - they work very well and exhibit high amounts of gain. "

=============

Actually, the Zepp is a resonant antenna it is an end-fed halfwave antenna. It is a high impedance antenna, however it is indeed resonant. IIRC, the curtain sterba is also a resoanat antenna as the lengths of each section of the antena are multiples of 1/4-wavelength. A good example of a non-resonant antenna with high gain would be the non-resonant or terminated Rhombic antenna; an example of a non-resonant antenna with little gain would be a windom (the original not the 'Carolina' antenna which wasn't designed by Laurent G. Windom and described in QST sometime in '29).

73 DE KAØGKT/7

--Steve

Reply to a comment by : W8WZ on 2007-02-23

Some Good points are made here - but one that is over looked in the article is that an antenna does NOT have to be resonant to have positive gain. Classic wire designs such as the Zepp, Extended Double Zepp, and Sterba Curtain are not resonant and will need to have some sort of antenna coupler to be used with a transmitter that is looking for a 50 ohm match. Nevertheless, when matched to the Xmtr with the transmatch - they work very well and exhibit high amounts of gain. Other antennas like the Fritzel will be technically resonant on many frequencys but with little or no gain. Also - in Amateur practice whener DB is used it is assumed that it is DBd - at least according to the handbook.
Reply to a comment by : W4LGH on 2007-02-22

W6TH Vito wrote.. ~"W4LGH Alan, I've heard enough of your bullshit, enough is enough."~ Well Mr Vito...That certainly was an educated response! I have seen it all in my career, from a 5 gallon bucket of dirt in a guys trunk, because the instructions said "This wire needs to go to EARTH ground", to a station engineer who wouldn't let anyone install any antennas upside down on his tower because he said, RF would leak out. I guess some people take things to litteral, and some don't take it litteral enough. A lot of good info in this thread, but again it goes to show you can not POST a good article here on eHam, no matter what, people will try to tear it apart. No one understands friendly debate. 73 de W4LGH - Alan
Reply to a comment by : W6TH on 2007-02-22

. W4LGH Alan, I've heard enough of your bullshit, enough is enough. W6TH .:
Reply to a comment by : W6TH on 2007-02-22

. Frequency = 1 divided by time. Time is relevant. Known as the Black Hole. No Myth. .:
Reply to a comment by : N3OX on 2007-02-22

"But the tuner was at the antenna feed point, matching the antenna impedance to the radio, it worked, and I certainly didn't have extra power to spare, but it would have worked BETTER, had the wire been resonant on the frequency I was using" Untrue.
Reply to a comment by : N3OX on 2007-02-22

W4LGH: The excerpt you quoted from that page explains that a center fed antenna has the lowest possible impedance when it's half-wave resonant (or three-halves or five halves, whatever); that is, if you fix the ***voltage*** you feed to an antenna, you'll get the most current, and therefore the biggest field, when it's an odd multiple of a half wave. If you force the same current in a similar, but nonresonant antenna, you get the same strength field (up to the antenna being a little bit shorter or longer which affects its gain in a minor fashion). If you had a magical transistor or tube that didn't care if the voltage was not in phase with the current and didn't care how high that voltage got, you would never have to match to a nonresonant antenna. We always say that we're "transforming the antenna impedance" with a network, but we could equally say "we're transforming the transmitter output up to a voltage with the proper phase to drive the a particular current into the antenna impedance" An article I found that's more precise: http://www.cv.nrao.edu/course/astr534/AntennaTheory.html There's a bunch of stuff later on that isn't particularly applicable to our current discussion, like the impedance of a black hole, but they do talk about reciprocity later on in the page. 73, Dan
Reply to a comment by : W6TH on 2007-02-22

. W4LGH We have been talking about transmitting antennas, I would like to know a specific purpose for using a non-resonant antenna on a transmitter. ..................................................... A long-wire antenna radiates more power in its most favorable direction than does a half wave resonant antenna in its most favorable direction. This power gain is secured at the expense of radiation in other directions. Would you like me to run some analytical Geometry for you? Maybe my math can convince you. Better yet, lets see what your math can do for me. 73, W6TH .:
Reply to a comment by : W4LGH on 2007-02-22

W6TH wrote..."This is no myth, but the truth. A resonant antenna and a non resonant antenna are both efficient antennas; non are better than the other, each has its own purpose for use." We have been talking about transmitting antennas, I would like to know a specific purpose for using a non-resonant antenna on a transmitter. If one truely understands resonance, I don't understand how anything can be as efficient as one that is resonant. And it is proven to you everytime you load up a transmitter. I certainly understand that weird things will work, but that doesn't make it so. I worked over 15 countries running 3 watts or less into a 50' wire fed at the end with an MFJ 16010 tuner. But the tuner was at the antenna feed point, matching the antenna impedance to the radio, it worked, and I certainly didn't have extra power to spare, but it would have worked BETTER, had the wire been resonant on the frequency I was using, certainly more efficient, as at resonancde the end of the wire looks like an open circuit, where as off resonance it begins to look like a short. 73 de W4LGH Alan http://www.w4lgh.com
Reply to a comment by : W6TH on 2007-02-22

. This is no myth, but the truth. A resonant antenna and a non resonant antenna are both efficient antennas; non are better than the other, each has its own purpose for use. W6TH .:
Reply to a comment by : WB2WIK on 2007-02-22

Not all solid state rigs reduce output power beginning at VSWR = 1.5. That is ultra conservative. The Ten Tec transceivers for years used a circuit breaker in the power supply to tell the transceiver when to "cut back power" due to high VSWR. They'd shut off! But until the breaker tripped, they'd keep transmitting. My Drake TR-7, by published specification, provides 90% of its full rated output power into a 2:1 VSWR and doesn't "fold back" to 50% (which is still about 75W output power) until VSWR = 5:1. That detail is listed here on the last page of the TR-7 brochure: http://wb4hfn.com/DRAKE/DrakeCatalogsBrochures/Brochure_TR7_04B.htm As such, the TR-7 hardly needs a tuner unless the user intends some pretty serious mismatches. Mine can easily produce 100W output power into a 3:1 mismatch, on any band. Without a tuner. It's largely a matter of "headroom" for the power amplifying devices selected. Margins include current, voltage and heat. One problem with a little rig like the FT-857 is its PA devices are small and its PA heatsink is *very* small, not capable of carrying much heat away from the devices, even with a fan. The TR-7 power amplifier heatsink alone (just the heatsink) is larger than the entire FT-857... WB2WIK/6
Reply to a comment by : K6HWH on 2007-02-22

"Every solidstate radio I have ever owned started shutting down power at a 1.5 swr." What about this? I have a Yaesu 857 that does indeed crank down transmit power if the SWR is the least bit off, ostensibly to prevent damage to the output transistors. If even a SWR of 5 does not diminish appreciable the antenna's ability to radiate, isn't this a mistake? Should I be looking for a way to defeat the 857's cautious approach to SWR?
Reply to a comment by : K3AN on 2007-02-22

This article is evidence that you can't determine the usefulness or accuracy of an article by the number of words. If you want useful, accurate information on antennas, please visit the L.B. Cebik web site www.cebik.com. For the last time, there is nothing magical about resonant antennas.
Reply to a comment by : N3OX on 2007-02-22

Respectfully, W4LGH, I would like to point out that you are the one muddying the waters about a *resonant antenna* and its radiating effectiveness. It is not true that antenna element resonance has anything to do with coupling power into the electromagnetic field around the antenna. The *REAL* part of the antenna impedance has two components, the radiation resistance and the loss resistance. That fraction of the power which is associated with "dissipation" in the radiation resistance is the power that gets radiated. The fraction associated with dissipation in the loss resistance goes up as heat. The power in the reactive part of the impedance is simply stored in fields around the antenna. That means that an antenna with an impedance of 70+j0 and one with an impedance of 70+j500 are radiating exactly the same amount of power if you can feed that power to them in the first place. You need to match the antenna system to the transmitter but resonance of the antenna element itself has nothing at all to do with the transfer of that power to radiating electromagnetic fields. If you are supplying 100W to the antenna, 100W minus the antenna losses is radiated, no matter whether or not the antenna element is resonant. 73, Dan
Reply to a comment by : W4LGH on 2007-02-22

You see, here we go again, a good article is written, it contains some great info. Some additional articles are written taken it a little further. Then come the people who truely do not understand what is being said, and either go on what they have seen, or what somebody else who truely doesn't understand told them. ==================================================== Now... AA4PB writes..."at resonance the antenna is inducing more power into the atmosphere ---------------------------------------------------- Can you point us to a definitive text that proves this, or even claims it to be true?" ==================================================== Now with a call like this, this guy is at least an "ADVANCED" class if not an "EXTRA" class, what I said is basic "Physics 101" Resonance is a common thread which runs through almost every branch of physics, and yet a lot of people have never studied it. Without resonance we wouldn't have radio, television, music, or swings on playgrounds, not to mention cool gismos like Tesla coils. Of course, resonance also has its dark side. It occasionally causes a bridge to collapse, a helicopter to fly apart, or other inconveniences. Unlike black holes, time travel, and quantum mechanics, resonance is common place and easy to observe. Yet, it is one of the most striking and unexpected phenomenon in all of physics. It is relative to everything. Here is a good link to read about it...hopefully it will explain.. http://www.intuitor.com/resonance/circuits.html Ever heard the term, "Dip the Plate" when tuning? Notice how the plate current drops but your output increases? Wonder why that is? Could it be your tank circuit has been tuned to resonance? Hmmm...your antenna is an extension of your tank circuit. And to K9IUQ...who wrote..."Also resonance of the SYSTEM has nothing to do with how well the antenna radiates. This is determined by MANY other factors. I have a wonderful Dummy load antenna under my desk that is resonant on all HF bands, however it doesnt seem to radiate very well since I haven't worked too many people with it."... I give up here, this guy just isn't with the program...A dummy LOAD is NOT resonate, it is a resistive LOAD designed to burn up the power by turning it into HEAT! Thats why they call it a dummy LOAD! (key word there is LOAD) Man..you guys say you want elmers, if you truely do not understand something, thats ok, there are people who do understand, and more than willing to help. 73 de W4LGH Alan http://www.w4lgh.com
Reply to a comment by : AA4PB on 2007-02-22

at resonance the antenna is inducing more power into the atmosphere ---------------------------------------------------- Can you point us to a definitive text that proves this, or even claims it to be true?
Reply to a comment by : K9IUQ on 2007-02-22

One TRUE statement was made, a RESONATE antenna will work BETTER than a NON_RESONATE antenna. People do NOT understand resonance ..................................................... The above is an false statement. An Antenna is resonant at ONLY ONE frequency. At any other frequency it is non-resonant. We all use non-resonant antennas (including you) on a daily basis. We make the antenna SYSTEM resonant with a tuner of one kind or another or live with SWR higher than 1:1. Agreed - the whole SYSTEM must be resonance -from the radio to the antenna. It makes little difference if the antenna itself is resonance or not.Many of the best performing wire antennas are non-resonant fed with open wire feeders and an antenna tuner. Also resonance of the SYSTEM has nothing to do with how well the antenna radiates. This is determined by MANY other factors. I have a wonderful Dummy load antenna under my desk that is resonant on all HF bands, however it doesnt seem to radiate very well since I haven't worked too many people with it. Please Pick Up an antenna Book like "Reflections" and learn the facts instead of trying to sell me 'some wonderful ocean front property in Arizona " K9IUQ
AA4PB2007-02-23
RE: Benchmarks
A speaker to an AF amp is exactly the same as an antenna to an RF amp.
------------------------------------------------
That completely ignores frequency, wavelength, transmission line theory and propogation modes.

That also ignores the fact that most large audio amplifiers are NOT designed to have a speaker load that matches the amplifier output impedance. Most professional amps have a very low output impedance (on the order of 2 ohms). They are often specified at X watts for 8 ohms, X watts for 4 ohms and some even X watts for 2 ohms.

For line level amps you find they often use an output impedance on the order of 100 ohms to drive loads of 10K ohms. Again, they are not looking for impedance matching as normally done with RF systems.

Reply to a comment by : AA4PB on 2007-02-23

If you read Maxwell's books you'll discover that the reflected power does not get dissipated in the matchbox or transmitter. 50% reflected power does NOT mean that only half the power gets radiated by the antenna. The reflected power travels back down the feed line (being attenuated once again by the feed line loss) until it reaches the conjugate match at the tuner (or transmitter). That match turns it around and sends it back up the feed line, again being subjected to the feed line loss. When it reaches the mismatch at the antenna a portion of it is radiated by the antenna and a portion of it is re-reflected back down the feed line for another trip. This keeps happening until all of the original power is either radiated by the antenna or dissipated by the feed line loss. It is this multiple trip scenario that results in increased feed line loss with high SWR.
Reply to a comment by : AA4PB on 2007-02-23

No,a matchbox does not divert the RF. A matchbox adds an equal and opposite reactance to make the antenna *system* resonant and converts the resistive component of the impedance to 50 ohms to match the transmitter. While a matchbox does have some losses, its primary means of matching impedances is NOT by converting power to heat as in a resistor or L-pad. Forgetting the reactive components, a matchbox operation is *similar* to impedance matching using a transformer. By the way, there is a lot of hype among consumer audio people about skin effect. Most any professional audio EE will tell you that skin effect is negligible at audio frequencies. Most of the hype comes from sales people trying to convince you to purchase their expensive audio cables.
Reply to a comment by : KC8QFP on 2007-02-23

AA4PB sez, ""Think of a matchbox as an output transformer on an amplifier. It matches the impedance of the speaker load to the impedance of the output tubes or transistors. Yes, transformers are still used in commercial audio amplifiers, primarily to match to a 70V distributed paging speaker system."" I would compare an output transformer to a BALUN or torroidial transformer, and not so much the caps and coils that direct the stray RF to ground. An Lpad has a hi-wattage resistor (often coil type) that diverts some of the power through the resistor, and some to the speaker. i.e. a transformer converts as in 4:1 etc., and a matchbox DIVERTS the RF. A matchbox is more akin to filters than transformers. transformers - converts matchbox/filters - diverts Let's say you have a two ohm speaker that you would like to connect to an eight ohm amp. Here are a few ways to do it. One would be to put a six ohm resistor (Lpad/reostat) series inline to the speaker (like a matchbox to me). Another way would be to use a (impedance) transformer (this would be connected in parellel). Another would be to use more speakers in series (my preferred method, like a resonant antenna). Antenna feedline does radiate some of the stray reflected RF, but a lot of it either seeks a path to ground through a tuner or the transmitter. It is called standing wave because it does NOT radiate efficiantly like an antenna. So speaker wire is simular. Radiation and dicipation is simply electricity seeking the lowest path of resistance, i.e. finding its easiest way to complete the circuit. Some finds its way by radiating from an antenna, as RF through space, to the other guys antenna and then through his receiver so to speak. Some energy finds a shortcut to ground through a tuner. The lowest possible path of resistance would be a short circuit because it is the "shortest" or least path of resistance.
Reply to a comment by : AA4PB on 2007-02-23

Speakers and audio amplfiers are quite different than antennas and RF. The wires connecting the speakers are very short in terms of the wavelength of the audio and they do not act as transmission lines. You don't have to deal with standing waves and reflected power on the speaker wires. It is true however that maximum power is transferred from the source to the load when the load impedance matches the source impedance. That's akin to matching the antenna SYSTEM to the transmitter which is why matchboxes are often used. It doesn't relate to resonance of an antenna however. Think of a matchbox as an output transformer on an amplifier. It matches the impedance of the speaker load to the impedance of the output tubes or transistors. Yes, transformers are still used in commercial audio amplifiers, primarily to match to a 70V distributed paging speaker system.
Reply to a comment by : AA4PB on 2007-02-23

Alan, I submit that the ends of a dipole (resonant or not) are ALWAYS open and ALWAYS high impedance. That is exactly what makes the feed impedance of a dipole change as you change its physical length. When each side of a dipole is an exact odd multiple of 1/4 wavelength long then the standing wave on the antenna transforms the high impedance at the end to a fairly low impedance at the center. If the antenna is some other (non-resonant) length then the standing wave transforms the high impedance at the end to some other impedance at the center. As long as you can match that impedance to the feed line you can transfer power into the antenna. If you can transfer power into an antenna then most of it (less the small I*R loss in the resistance of the wire) will be radiated. An antenna has basically two ways to get rid of the power that gets applied to it. Either is is radiated or it is turned to heat. The only thing that can turn it to heat is the resistance of the wire. Since the resistance of the wire in a typical doublet antenna is very low, most of the power must be radiated. Making an antenna a non-resonant length does not change the resistance of the wire therefore it doesn't raise the amount of power disipated as heat by any significant amount.
Reply to a comment by : AD4U on 2007-02-23

Doing something to add 1 or 2 dB to your signal may not make much difference by itself. However if you have the $$ and the time and the expertise, making changes that add a dB here and a dB there and another dB somewhere else, collectively WILL make a noticeable difference. This is often what separates the BIG GUNS from the little pistols.
AD5VJ2007-02-23
RE: Benchmarks
Reciprocity is true if one is in the near field. However, when you consider propagation effects the effect of reciprocity fails to prove itself consistant. Other factors come into play and many times negate either reciprical property.

I work alot of DX from a double bazooka antenna on 80 meters which is only 30 feet at the apex and 20 feet in height at the ends.

The stations I work mostly have much better antenna systems, therefore, make the contact possible.

The rx system must figure in when considering your own systems effecency.
----
tnx Bob AD5VJ
http://www.ad5vj.com
----
Reply to a comment by : ONAIR on 2007-02-22

Interesting point. So a resonant vertical dipole would then be a lot more efficient than a vertical that you would need to tune?
AA4PB2007-02-23
RE: Benchmarks
If you read Maxwell's books you'll discover that the reflected power does not get dissipated in the matchbox or transmitter. 50% reflected power does NOT mean that only half the power gets radiated by the antenna.

The reflected power travels back down the feed line (being attenuated once again by the feed line loss) until it reaches the conjugate match at the tuner (or transmitter). That match turns it around and sends it back up the feed line, again being subjected to the feed line loss. When it reaches the mismatch at the antenna a portion of it is radiated by the antenna and a portion of it is re-reflected back down the feed line for another trip. This keeps happening until all of the original power is either radiated by the antenna or dissipated by the feed line loss. It is this multiple trip scenario that results in increased feed line loss with high SWR.
Reply to a comment by : AA4PB on 2007-02-23

No,a matchbox does not divert the RF. A matchbox adds an equal and opposite reactance to make the antenna *system* resonant and converts the resistive component of the impedance to 50 ohms to match the transmitter. While a matchbox does have some losses, its primary means of matching impedances is NOT by converting power to heat as in a resistor or L-pad. Forgetting the reactive components, a matchbox operation is *similar* to impedance matching using a transformer. By the way, there is a lot of hype among consumer audio people about skin effect. Most any professional audio EE will tell you that skin effect is negligible at audio frequencies. Most of the hype comes from sales people trying to convince you to purchase their expensive audio cables.
Reply to a comment by : KC8QFP on 2007-02-23

AA4PB sez, ""Think of a matchbox as an output transformer on an amplifier. It matches the impedance of the speaker load to the impedance of the output tubes or transistors. Yes, transformers are still used in commercial audio amplifiers, primarily to match to a 70V distributed paging speaker system."" I would compare an output transformer to a BALUN or torroidial transformer, and not so much the caps and coils that direct the stray RF to ground. An Lpad has a hi-wattage resistor (often coil type) that diverts some of the power through the resistor, and some to the speaker. i.e. a transformer converts as in 4:1 etc., and a matchbox DIVERTS the RF. A matchbox is more akin to filters than transformers. transformers - converts matchbox/filters - diverts Let's say you have a two ohm speaker that you would like to connect to an eight ohm amp. Here are a few ways to do it. One would be to put a six ohm resistor (Lpad/reostat) series inline to the speaker (like a matchbox to me). Another way would be to use a (impedance) transformer (this would be connected in parellel). Another would be to use more speakers in series (my preferred method, like a resonant antenna). Antenna feedline does radiate some of the stray reflected RF, but a lot of it either seeks a path to ground through a tuner or the transmitter. It is called standing wave because it does NOT radiate efficiantly like an antenna. So speaker wire is simular. Radiation and dicipation is simply electricity seeking the lowest path of resistance, i.e. finding its easiest way to complete the circuit. Some finds its way by radiating from an antenna, as RF through space, to the other guys antenna and then through his receiver so to speak. Some energy finds a shortcut to ground through a tuner. The lowest possible path of resistance would be a short circuit because it is the "shortest" or least path of resistance.
Reply to a comment by : AA4PB on 2007-02-23

Speakers and audio amplfiers are quite different than antennas and RF. The wires connecting the speakers are very short in terms of the wavelength of the audio and they do not act as transmission lines. You don't have to deal with standing waves and reflected power on the speaker wires. It is true however that maximum power is transferred from the source to the load when the load impedance matches the source impedance. That's akin to matching the antenna SYSTEM to the transmitter which is why matchboxes are often used. It doesn't relate to resonance of an antenna however. Think of a matchbox as an output transformer on an amplifier. It matches the impedance of the speaker load to the impedance of the output tubes or transistors. Yes, transformers are still used in commercial audio amplifiers, primarily to match to a 70V distributed paging speaker system.
Reply to a comment by : AA4PB on 2007-02-23

Alan, I submit that the ends of a dipole (resonant or not) are ALWAYS open and ALWAYS high impedance. That is exactly what makes the feed impedance of a dipole change as you change its physical length. When each side of a dipole is an exact odd multiple of 1/4 wavelength long then the standing wave on the antenna transforms the high impedance at the end to a fairly low impedance at the center. If the antenna is some other (non-resonant) length then the standing wave transforms the high impedance at the end to some other impedance at the center. As long as you can match that impedance to the feed line you can transfer power into the antenna. If you can transfer power into an antenna then most of it (less the small I*R loss in the resistance of the wire) will be radiated. An antenna has basically two ways to get rid of the power that gets applied to it. Either is is radiated or it is turned to heat. The only thing that can turn it to heat is the resistance of the wire. Since the resistance of the wire in a typical doublet antenna is very low, most of the power must be radiated. Making an antenna a non-resonant length does not change the resistance of the wire therefore it doesn't raise the amount of power disipated as heat by any significant amount.
Reply to a comment by : AD4U on 2007-02-23

Doing something to add 1 or 2 dB to your signal may not make much difference by itself. However if you have the $$ and the time and the expertise, making changes that add a dB here and a dB there and another dB somewhere else, collectively WILL make a noticeable difference. This is often what separates the BIG GUNS from the little pistols.
W4LGH2007-02-23
RE: Benchmarks
K0IZ wrote.."Not sure about your long-term broadcast experience, but ... Broadcast band antennas (towers) are rarely (if ever) full 1/4 wave verticals. No problem - a matching network at the base cancels the reactance. Other than slight loss in the network, all of the transmitter power is radiated. THe antenna is NOT resonant, the antenna system IS. So ... several thousand examples."

I have been a broadcast engineer for 30+ years, Ham radio and 1st class license for 43+ years.

Someone does understand where I have been coming from. Yes Am broadcast towers, except a few at the hi end of the band are less than a 1/4wave. You add a matching network to tune out the reactance, therefore
making the antenna system resonant. Hams do the same thing.

I also want to set the record staight, that I never said an antenna had to resonant to work, I said it was at it PEAK effeciency at resonance! I have also NEVER mentioned an SWR of 1:1 in order for it to work. My antennas are NOT 1:1 and anything under 3:1 works ok for me. I also said you CAN NOT tune your antenna with an antenna tuner in your shack hooked to un-balanced line(coax). You can however tune the antenna with a tuner or matching network AT the antenna, this is done all the time with load coils, and other matching networks, and these devices are used to make the antenna resonate, which has to do with resonance.

And I also agree with the poster about speakers and antennas. A speaker to an AF amp is exactly the same as an antenna to an RF amp. The same principles apply only at lower audio frequencies. Everything in life is relative, and there is nothing new under the Sun!

73 de W4LGH Alan
http://www.w4lgh.com

Reply to a comment by : KC8QFP on 2007-02-23

AA4PB sez, ""Think of a matchbox as an output transformer on an amplifier. It matches the impedance of the speaker load to the impedance of the output tubes or transistors. Yes, transformers are still used in commercial audio amplifiers, primarily to match to a 70V distributed paging speaker system."" I would compare an output transformer to a BALUN or torroidial transformer, and not so much the caps and coils that direct the stray RF to ground. An Lpad has a hi-wattage resistor (often coil type) that diverts some of the power through the resistor, and some to the speaker. i.e. a transformer converts as in 4:1 etc., and a matchbox DIVERTS the RF. A matchbox is more akin to filters than transformers. transformers - converts matchbox/filters - diverts Let's say you have a two ohm speaker that you would like to connect to an eight ohm amp. Here are a few ways to do it. One would be to put a six ohm resistor (Lpad/reostat) series inline to the speaker (like a matchbox to me). Another way would be to use a (impedance) transformer (this would be connected in parellel). Another would be to use more speakers in series (my preferred method, like a resonant antenna). Antenna feedline does radiate some of the stray reflected RF, but a lot of it either seeks a path to ground through a tuner or the transmitter. It is called standing wave because it does NOT radiate efficiantly like an antenna. So speaker wire is simular. Radiation and dicipation is simply electricity seeking the lowest path of resistance, i.e. finding its easiest way to complete the circuit. Some finds its way by radiating from an antenna, as RF through space, to the other guys antenna and then through his receiver so to speak. Some energy finds a shortcut to ground through a tuner. The lowest possible path of resistance would be a short circuit because it is the "shortest" or least path of resistance.
Reply to a comment by : AA4PB on 2007-02-23

Speakers and audio amplfiers are quite different than antennas and RF. The wires connecting the speakers are very short in terms of the wavelength of the audio and they do not act as transmission lines. You don't have to deal with standing waves and reflected power on the speaker wires. It is true however that maximum power is transferred from the source to the load when the load impedance matches the source impedance. That's akin to matching the antenna SYSTEM to the transmitter which is why matchboxes are often used. It doesn't relate to resonance of an antenna however. Think of a matchbox as an output transformer on an amplifier. It matches the impedance of the speaker load to the impedance of the output tubes or transistors. Yes, transformers are still used in commercial audio amplifiers, primarily to match to a 70V distributed paging speaker system.
Reply to a comment by : AA4PB on 2007-02-23

Alan, I submit that the ends of a dipole (resonant or not) are ALWAYS open and ALWAYS high impedance. That is exactly what makes the feed impedance of a dipole change as you change its physical length. When each side of a dipole is an exact odd multiple of 1/4 wavelength long then the standing wave on the antenna transforms the high impedance at the end to a fairly low impedance at the center. If the antenna is some other (non-resonant) length then the standing wave transforms the high impedance at the end to some other impedance at the center. As long as you can match that impedance to the feed line you can transfer power into the antenna. If you can transfer power into an antenna then most of it (less the small I*R loss in the resistance of the wire) will be radiated. An antenna has basically two ways to get rid of the power that gets applied to it. Either is is radiated or it is turned to heat. The only thing that can turn it to heat is the resistance of the wire. Since the resistance of the wire in a typical doublet antenna is very low, most of the power must be radiated. Making an antenna a non-resonant length does not change the resistance of the wire therefore it doesn't raise the amount of power disipated as heat by any significant amount.
Reply to a comment by : AD4U on 2007-02-23

Doing something to add 1 or 2 dB to your signal may not make much difference by itself. However if you have the $$ and the time and the expertise, making changes that add a dB here and a dB there and another dB somewhere else, collectively WILL make a noticeable difference. This is often what separates the BIG GUNS from the little pistols.
AA4PB2007-02-23
RE: Benchmarks
No,a matchbox does not divert the RF. A matchbox adds an equal and opposite reactance to make the antenna *system* resonant and converts the resistive component of the impedance to 50 ohms to match the transmitter. While a matchbox does have some losses, its primary means of matching impedances is NOT by converting power to heat as in a resistor or L-pad.

Forgetting the reactive components, a matchbox operation is *similar* to impedance matching using a transformer.

By the way, there is a lot of hype among consumer audio people about skin effect. Most any professional audio EE will tell you that skin effect is negligible at audio frequencies. Most of the hype comes from sales people trying to convince you to purchase their expensive audio cables.
Reply to a comment by : KC8QFP on 2007-02-23

AA4PB sez, ""Think of a matchbox as an output transformer on an amplifier. It matches the impedance of the speaker load to the impedance of the output tubes or transistors. Yes, transformers are still used in commercial audio amplifiers, primarily to match to a 70V distributed paging speaker system."" I would compare an output transformer to a BALUN or torroidial transformer, and not so much the caps and coils that direct the stray RF to ground. An Lpad has a hi-wattage resistor (often coil type) that diverts some of the power through the resistor, and some to the speaker. i.e. a transformer converts as in 4:1 etc., and a matchbox DIVERTS the RF. A matchbox is more akin to filters than transformers. transformers - converts matchbox/filters - diverts Let's say you have a two ohm speaker that you would like to connect to an eight ohm amp. Here are a few ways to do it. One would be to put a six ohm resistor (Lpad/reostat) series inline to the speaker (like a matchbox to me). Another way would be to use a (impedance) transformer (this would be connected in parellel). Another would be to use more speakers in series (my preferred method, like a resonant antenna). Antenna feedline does radiate some of the stray reflected RF, but a lot of it either seeks a path to ground through a tuner or the transmitter. It is called standing wave because it does NOT radiate efficiantly like an antenna. So speaker wire is simular. Radiation and dicipation is simply electricity seeking the lowest path of resistance, i.e. finding its easiest way to complete the circuit. Some finds its way by radiating from an antenna, as RF through space, to the other guys antenna and then through his receiver so to speak. Some energy finds a shortcut to ground through a tuner. The lowest possible path of resistance would be a short circuit because it is the "shortest" or least path of resistance.
Reply to a comment by : AA4PB on 2007-02-23

Speakers and audio amplfiers are quite different than antennas and RF. The wires connecting the speakers are very short in terms of the wavelength of the audio and they do not act as transmission lines. You don't have to deal with standing waves and reflected power on the speaker wires. It is true however that maximum power is transferred from the source to the load when the load impedance matches the source impedance. That's akin to matching the antenna SYSTEM to the transmitter which is why matchboxes are often used. It doesn't relate to resonance of an antenna however. Think of a matchbox as an output transformer on an amplifier. It matches the impedance of the speaker load to the impedance of the output tubes or transistors. Yes, transformers are still used in commercial audio amplifiers, primarily to match to a 70V distributed paging speaker system.
Reply to a comment by : AA4PB on 2007-02-23

Alan, I submit that the ends of a dipole (resonant or not) are ALWAYS open and ALWAYS high impedance. That is exactly what makes the feed impedance of a dipole change as you change its physical length. When each side of a dipole is an exact odd multiple of 1/4 wavelength long then the standing wave on the antenna transforms the high impedance at the end to a fairly low impedance at the center. If the antenna is some other (non-resonant) length then the standing wave transforms the high impedance at the end to some other impedance at the center. As long as you can match that impedance to the feed line you can transfer power into the antenna. If you can transfer power into an antenna then most of it (less the small I*R loss in the resistance of the wire) will be radiated. An antenna has basically two ways to get rid of the power that gets applied to it. Either is is radiated or it is turned to heat. The only thing that can turn it to heat is the resistance of the wire. Since the resistance of the wire in a typical doublet antenna is very low, most of the power must be radiated. Making an antenna a non-resonant length does not change the resistance of the wire therefore it doesn't raise the amount of power disipated as heat by any significant amount.
Reply to a comment by : AD4U on 2007-02-23

Doing something to add 1 or 2 dB to your signal may not make much difference by itself. However if you have the $$ and the time and the expertise, making changes that add a dB here and a dB there and another dB somewhere else, collectively WILL make a noticeable difference. This is often what separates the BIG GUNS from the little pistols.
KC8QFP2007-02-23
RE: Benchmarks
AA4PB sez, ""Think of a matchbox as an output transformer on an amplifier. It matches the impedance of the speaker load to the impedance of the output tubes or transistors. Yes, transformers are still used in commercial audio amplifiers, primarily to match to a 70V distributed paging speaker system.""

I would compare an output transformer to a BALUN or torroidial transformer, and not so much the caps and coils that direct the stray RF to ground. An Lpad has a hi-wattage resistor (often coil type) that diverts some of the power through the resistor, and some to the speaker. i.e. a transformer converts as in 4:1 etc., and a matchbox DIVERTS the RF. A matchbox is more akin to filters than transformers.

transformers - converts
matchbox/filters - diverts

Let's say you have a two ohm speaker that you would like to connect to an eight ohm amp. Here are a few ways to do it. One would be to put a six ohm resistor (Lpad/reostat) series inline to the speaker (like a matchbox to me). Another way would be to use a (impedance) transformer (this would be connected in parellel). Another would be to use more speakers in series (my preferred method, like a resonant antenna).

Antenna feedline does radiate some of the stray reflected RF, but a lot of it either seeks a path to ground through a tuner or the transmitter. It is called standing wave because it does NOT radiate efficiantly like an antenna. So speaker wire is simular. Radiation and dicipation is simply electricity seeking the lowest path of resistance, i.e. finding its easiest way to complete the circuit. Some finds its way by radiating from an antenna, as RF through space, to the other guys antenna and then through his receiver so to speak. Some energy finds a shortcut to ground through a tuner. The lowest possible path of resistance would be a short circuit because it is the "shortest" or least path of resistance.
Reply to a comment by : AA4PB on 2007-02-23

Speakers and audio amplfiers are quite different than antennas and RF. The wires connecting the speakers are very short in terms of the wavelength of the audio and they do not act as transmission lines. You don't have to deal with standing waves and reflected power on the speaker wires. It is true however that maximum power is transferred from the source to the load when the load impedance matches the source impedance. That's akin to matching the antenna SYSTEM to the transmitter which is why matchboxes are often used. It doesn't relate to resonance of an antenna however. Think of a matchbox as an output transformer on an amplifier. It matches the impedance of the speaker load to the impedance of the output tubes or transistors. Yes, transformers are still used in commercial audio amplifiers, primarily to match to a 70V distributed paging speaker system.
Reply to a comment by : AA4PB on 2007-02-23

Alan, I submit that the ends of a dipole (resonant or not) are ALWAYS open and ALWAYS high impedance. That is exactly what makes the feed impedance of a dipole change as you change its physical length. When each side of a dipole is an exact odd multiple of 1/4 wavelength long then the standing wave on the antenna transforms the high impedance at the end to a fairly low impedance at the center. If the antenna is some other (non-resonant) length then the standing wave transforms the high impedance at the end to some other impedance at the center. As long as you can match that impedance to the feed line you can transfer power into the antenna. If you can transfer power into an antenna then most of it (less the small I*R loss in the resistance of the wire) will be radiated. An antenna has basically two ways to get rid of the power that gets applied to it. Either is is radiated or it is turned to heat. The only thing that can turn it to heat is the resistance of the wire. Since the resistance of the wire in a typical doublet antenna is very low, most of the power must be radiated. Making an antenna a non-resonant length does not change the resistance of the wire therefore it doesn't raise the amount of power disipated as heat by any significant amount.
Reply to a comment by : AD4U on 2007-02-23

Doing something to add 1 or 2 dB to your signal may not make much difference by itself. However if you have the $$ and the time and the expertise, making changes that add a dB here and a dB there and another dB somewhere else, collectively WILL make a noticeable difference. This is often what separates the BIG GUNS from the little pistols.
K0IZ2007-02-23
RE: Benchmarks
Alan, K0BG - good post. Like your mobile web site. Good info!

ALan, W4LGH - you said "I will also tell you that there is NOT a commercial installation of any broadcast systems out there that would use non-resonant antenna! Been in the broadcast industry to long to know better. So I am still waiting on an example for the use of a non-resonant antenna hooked to a transmitter."

Not sure about your long-term broadcast experience, but ... Broadcast band antennas (towers) are rarely (if ever) full 1/4 wave verticals. No problem - a matching network at the base cancels the reactance. Other than slight loss in the network, all of the transmitter power is radiated. THe antenna is NOT resonant, the antenna system IS. So ... several thousand examples.

At the other end of the spectrum, antennas on satellites are rarely resonant due to physical constraints. But matching networks take care of the problem, again with only minimal loss.

Installing a matching network at the antenna means almost all of the tranmitted power will be radiated (all, that is except for losses in the network itself).

Installing a matching network (antenna tuner)at the transmitter adds the feedline losses, which might be great (coax, higher freq, high SWR, long length), or not much (open wire, lower freq).

In either case the reactance of the antenna is cancelled and the antenna SYSTEM is resonant.

John Raydo
Reply to a comment by : ONAIR on 2007-02-22

Interesting point. So a resonant vertical dipole would then be a lot more efficient than a vertical that you would need to tune?
W4LGH2007-02-23
RE: Benchmarks
Seems we don't understand "Skin Effect" either..ok...
Here's a deffination...
skin effect

Skin effect is a tendency for alternating current (AC) to flow mostly near the outer surface of
a solid electrical conductor, such as metal wire, at frequencies above the audio range. The effect
becomes more and more apparent as the frequency increases.
The main problem with skin effect is that it increases the effective resistance of a wire for AC
at moderate to high frequencies, compared with the resistance of the same wire at direct current (DC)
and low AC frequencies. The effect is most pronounced in radio-frequency (RF) systems, especially
antennas and transmission lines. But it can also affect the performance of high-fidelity sound
equipment by causing attenuation in the treble range (the highest-pitched components of the audio).

Skin effect can be reduced by using stranded rather than solid wire. This increases the effective
surface area of the wire for a given wire gauge. Tinned wire should be avoided because tin has higher
resistance than copper. In large RF antenna arrays, hollow tubing can be used in place of solid rods
with little or no loss of efficiency; in this respect, skin effect is an asset. It also works in favor
of the use of copper-clad steel wire for more modest antennas. Such wire is mechanically stronger than
solid or stranded copper, because steel has a higher tensile strength than copper. The skin effect causes
most of the current to flow through the copper cladding, which is a better electrical conductor than steel.
--------
AA4PB wrote..
~As long as you can match that impedance to the feed line you can transfer power into the antenna. If you can transfer power into an antenna then most of it (less the small I*R loss in the resistance of the wire) will be radiated.
---------
What you say here holds some truth, if the non-resoanant antenna is not far off resonance. Case in point, you can load a 10penny nail up on 80 meters by matching its impedance, but I do NOT think you will radiate much power!
---------
If you truely believe that the ends of an antenna are open at all times then what develops the standing waves on a non-resonant antenna. I submit that the ends look more electrically shorted thus reflecting the normally radiated energy back down the antenna. This reflected power also create changes at the feedpoint impedance.
----------
I liked the post about antennas and antenna systems.
LIke I have been saying there is something being lost in the translation here. There is NOT a professional broadcaster out there using a non-resonant antenna, unless it is part or a multi-antenna system and it is being used out of phase to decouple other parts of the antenna. Stirba curtains/rombics & Beverages are all multi-antennas used to make up a single antenna system. The antenna system is resonant, even tho it is made up of both resonant and non-resonant elements.

Here is another great link...
http://www.radio-electronics.com/info/antennas/basics/resonance.php

73 de W4LGH - Alan
http://www.w4lgh.com




Reply to a comment by : N1XBP on 2007-02-23

Sometimes I think eHam is a lost cause. I think this thread devolved after a bit of debate about receive/transmit performance not being equal on an antenna. Then someone misunderstood that as being false because of reciprocity of pattern and gain. Those are two seperate issues. If antennas transmit just as well as they receive, why don't we all transmit into beverages? Yes, reciprocity holds true for the pattern and gain, except in the real world the ground losses cause it to be a lousy transmit antenna. See the conceptual difference now? As for antenna resonance, there are circles being gone through here. The antenna and the antenna system are not exactly one in the same. I can have a resonant antenna system with a non resonant antenna element. Then, some people seem to think that you can't feed a non resonant antenna without a tuner. Not true if you pick a feed point that has the impedance you want for the frequency you intend to use. What your pattern will look like is another story. And last, 1:1 SWR isn't entirely related to resonance, since impedance is a complex number and a high non reactive componant will lower the SWR by lowering the Q of the tuned circuit the antenna system represents and burning up more of the power that would have been reflected as heat.
Reply to a comment by : AA4PB on 2007-02-23

Alan, I submit that the ends of a dipole (resonant or not) are ALWAYS open and ALWAYS high impedance. That is exactly what makes the feed impedance of a dipole change as you change its physical length. When each side of a dipole is an exact odd multiple of 1/4 wavelength long then the standing wave on the antenna transforms the high impedance at the end to a fairly low impedance at the center. If the antenna is some other (non-resonant) length then the standing wave transforms the high impedance at the end to some other impedance at the center. As long as you can match that impedance to the feed line you can transfer power into the antenna. If you can transfer power into an antenna then most of it (less the small I*R loss in the resistance of the wire) will be radiated. An antenna has basically two ways to get rid of the power that gets applied to it. Either is is radiated or it is turned to heat. The only thing that can turn it to heat is the resistance of the wire. Since the resistance of the wire in a typical doublet antenna is very low, most of the power must be radiated. Making an antenna a non-resonant length does not change the resistance of the wire therefore it doesn't raise the amount of power disipated as heat by any significant amount.
Reply to a comment by : AD4U on 2007-02-23

Doing something to add 1 or 2 dB to your signal may not make much difference by itself. However if you have the $$ and the time and the expertise, making changes that add a dB here and a dB there and another dB somewhere else, collectively WILL make a noticeable difference. This is often what separates the BIG GUNS from the little pistols.
AA4PB2007-02-23
RE: Benchmarks
many people falsely think increasing antenna gain will bring an equal dividend on receiving and transmitting and wrongly cite the "reciprocity" rule as proof.
-----------------------------------------------------
I absolutly agree. However, I have been told (right here on e-ham) that my tests that showed an equal absolute level of received signal between two antennas on receive was invalid because antennas were not reciprical. They claimed that even though the antennas received the same amount of signal they would not transmit the same amount of signal. Their claim was that antennas must be compared on transmit to be valid. The "reciprocity" rule says that if an antenna shows a 3dB increase in received signal strength (not signal to noise) then it will show a 3dB increase in transmit signal level.

The thing is you have to be careful about is whether you are comparing signal level measurements or signal to noise ratios (i.e. the ability to copy signals). In some cases (most from a practical aspect) it is the S/N ratio and ability to copy stations that is important while in other cases it can be the gain and pattern that is important.
Reply to a comment by : AA4PB on 2007-02-23

Speakers and audio amplfiers are quite different than antennas and RF. The wires connecting the speakers are very short in terms of the wavelength of the audio and they do not act as transmission lines. You don't have to deal with standing waves and reflected power on the speaker wires. It is true however that maximum power is transferred from the source to the load when the load impedance matches the source impedance. That's akin to matching the antenna SYSTEM to the transmitter which is why matchboxes are often used. It doesn't relate to resonance of an antenna however. Think of a matchbox as an output transformer on an amplifier. It matches the impedance of the speaker load to the impedance of the output tubes or transistors. Yes, transformers are still used in commercial audio amplifiers, primarily to match to a 70V distributed paging speaker system.
Reply to a comment by : AA4PB on 2007-02-23

Alan, I submit that the ends of a dipole (resonant or not) are ALWAYS open and ALWAYS high impedance. That is exactly what makes the feed impedance of a dipole change as you change its physical length. When each side of a dipole is an exact odd multiple of 1/4 wavelength long then the standing wave on the antenna transforms the high impedance at the end to a fairly low impedance at the center. If the antenna is some other (non-resonant) length then the standing wave transforms the high impedance at the end to some other impedance at the center. As long as you can match that impedance to the feed line you can transfer power into the antenna. If you can transfer power into an antenna then most of it (less the small I*R loss in the resistance of the wire) will be radiated. An antenna has basically two ways to get rid of the power that gets applied to it. Either is is radiated or it is turned to heat. The only thing that can turn it to heat is the resistance of the wire. Since the resistance of the wire in a typical doublet antenna is very low, most of the power must be radiated. Making an antenna a non-resonant length does not change the resistance of the wire therefore it doesn't raise the amount of power disipated as heat by any significant amount.
Reply to a comment by : AD4U on 2007-02-23

Doing something to add 1 or 2 dB to your signal may not make much difference by itself. However if you have the $$ and the time and the expertise, making changes that add a dB here and a dB there and another dB somewhere else, collectively WILL make a noticeable difference. This is often what separates the BIG GUNS from the little pistols.
K9IUQ2007-02-23
Benchmarks
From KE4HZN -Ah yes, the famous "it has to be cut to the band" crap. Pure unadulterated bull**it!! Tell all the broadcast engineers at every AM broadcast station in the world and every shortwave broadcast engineer in the world that their doing it all wrong by using nonresonant antennas. And then be prepared to be made a fool of by them when they laugh in your face and explain why your full of crap.

.....................................................

Amazing isn't it how this "the antennas gotta be resonant" mis-information just keeps getting spread by un-knowledgeable hams. And the sad fact is Hams Like W4LGH fervently believe themselves and try to make believers out of everyone. For 46 years I have been a ham and this subject of resonant vs nonresonant antennas, my SWR better be low or it wont radiate, etc. keeps getting debated. I rarely get into the debate, past experience has taught me people don't want to take the time to study the antenna literature and learn the truth. Trying to convince Hams like W4LGH that they are wrong is like trying to convince a Republican that a Democrat can govern better. It just isn't going to happen.

Stan K9IUQ




KC8QFP2007-02-23
RE: Benchmarks
PPS:

Antenna - Speaker
multi-band antenna - three way speaker system
matchbox - LPad (pot)
traps - crossovers
feedline - speaker wire
type of antenna - type of speaker (woofer, mid, tweeter)
beam antennaes - speaker baffle or enclosures
radiators (elements) - voice coils

That's probably adequite to make analogies.

Where does the power go from the amplifier?

Feedline: If you have two hundred feet of 18ga speaker wire, or twenty feet of 16ga, which will have more loss? Which is better to feed the power to the speaker, coax, or twin-lead zip cord (two hundred feet away)?

Resonance/resistance: An eight ohm voice coil may show about six ohms on an ohm meter. But get that voice coil moving back and forth within its magnet at high power, and then it is no longer eight ohms. The temp of the voice coil also hs an effect on its resistance, but the movement over the magnet will induce a reactance. When the speaker is matched properly, more sound will be reproduced via vibrations, rather thn dicipated as heat or bounced back down the feedline. I am trying to show how an antenna can either radiate the RF, or dicipate it as heat (through a matchbox or traps), or reflect it back down the feedline. (Another consideration in efficiancy is good connections along the way - a loose connection can do more harm than a trap).

How do we measure a good matched/operating system? One way is meters to indicate wattage, continuity, VSWR and so on. Another way is touch, feel the HEAT on your finals, matchbox, etc. Another is malfunction, it simply does not work, you cannot be heard very well.

I've been into hifi longer than ham radio, (40+ years), and it helped me to get my ticket since the two hobbies are very simular, one is AF and the other is RF. I hope this will take this discussion into a deeper way of explaing something that is familiar to a lot of people, their stereo, and something new and unfamiliar to them, RF and ham radio.

73, Don
we are elmers too
Reply to a comment by : KC8QFP on 2007-02-23

PS: An after-thought... using traps to me is akin to using a five watt voicecoil on a 200 watt amplifier. It works OK until you crank up the power, then it's fried! You can play with the numbers, but I try to find the most efficient antenna to do the job with my transmitter - a matched system, rather than a "matchbox and traps". Using caps and coils as filters would be like crossovers for woofers and tweeters. Funny thing, I prefer to bi-amp for the different freqs, a speaker per amp - this would be like using a separate antenna per band rather than a multi-band antenna (multi-band antenna is like a three way speaker system with crossovers, instead of a separate speaker, each having its own amp). Comparring AF and RF, may be a better way to understand. Don
Reply to a comment by : KC8QFP on 2007-02-23

I kind of think of matching antennaes like matching speakers on my HIFI system (another hobby I really enjoy besides ham radio - hihi). Eight ohms, one speaker, two speakers, three, four etc., there are a number of ways to match the speakers (series, parellel, series/parellel). If you use sixteen ohms, four ohms, two ohms, and so forth, they will work on an amplifier that is made for eight ohms, but... kick up the power and see how hot the amp gets? The most efficient radiation from the speaker system depends on it matching its amplifier. A tuner or matchbox reminds me of using an LPad to control the volume of a speaker, it does not radiate any sound, but warms up and keeps a match on the amp whilst it turn down the loudness, not the best way to do it. The standard could be the eight ohm voice coil, as it is the dipole. If you have a two ohm speaker, an Lpad would be a way to match it to eight owm's. I like to KISS, and perhaps using speakers would simplify the discussion for the new guys. Don PS: Some of the new guys used the coat hanger as their antenna standard to compare with!!! HIHI!
Reply to a comment by : KE4ZHN on 2007-02-23

Ah yes, the famous "it has to be cut to the band" crap. Pure unadulterated bull**it!! Tell all the broadcast engineers at every AM broadcast station in the world and every shortwave broadcast engineer in the world that their doing it all wrong by using nonresonant antennas. And then be prepared to be made a fool of by them when they laugh in your face and explain why your full of crap. If they can stop laughing long enough to. The same way I laugh when I hear this nonsense time and time again repeated on the air. Especially when I work stations many of them cant even hear on their so called resonant antennas cut to the band. I love my 600 ohm ladderline fed 80 mtr. doublet. Since these have been around since the 20`s and 30`s I guess they just dont work at all. Its such a lousy antenna that its been around for around 80 years and yet they still dont work worth a crap. Amazing isnt it? Yeah, and those nonresonant rhombics VOA uses sure are pi$$ weak. Maybe thats why they have to run 500kw into the arrays just to make up for all those losses? lol The engineers at VOA must have to hose down the antennas and matching networks to cool the heat from the excessive losses those lousy nonresonant antennas generate. Yeah....right! Its going to take me a week to shovel all the BS out of my shack after reading some of this nonsense.
N1XBP2007-02-23
RE: Benchmarks
Sometimes I think eHam is a lost cause. I think this thread devolved after a bit of debate about receive/transmit performance not being equal on an antenna. Then someone misunderstood that as being false because of reciprocity of pattern and gain. Those are two seperate issues.

If antennas transmit just as well as they receive, why don't we all transmit into beverages? Yes, reciprocity holds true for the pattern and gain, except in the real world the ground losses cause it to be a lousy transmit antenna. See the conceptual difference now?

As for antenna resonance, there are circles being gone through here. The antenna and the antenna system are not exactly one in the same. I can have a resonant antenna system with a non resonant antenna element.

Then, some people seem to think that you can't feed a non resonant antenna without a tuner. Not true if you pick a feed point that has the impedance you want for the frequency you intend to use. What your pattern will look like is another story.

And last, 1:1 SWR isn't entirely related to resonance, since impedance is a complex number and a high non reactive componant will lower the SWR by lowering the Q of the tuned circuit the antenna system represents and burning up more of the power that would have been reflected as heat.
Reply to a comment by : AA4PB on 2007-02-23

Alan, I submit that the ends of a dipole (resonant or not) are ALWAYS open and ALWAYS high impedance. That is exactly what makes the feed impedance of a dipole change as you change its physical length. When each side of a dipole is an exact odd multiple of 1/4 wavelength long then the standing wave on the antenna transforms the high impedance at the end to a fairly low impedance at the center. If the antenna is some other (non-resonant) length then the standing wave transforms the high impedance at the end to some other impedance at the center. As long as you can match that impedance to the feed line you can transfer power into the antenna. If you can transfer power into an antenna then most of it (less the small I*R loss in the resistance of the wire) will be radiated. An antenna has basically two ways to get rid of the power that gets applied to it. Either is is radiated or it is turned to heat. The only thing that can turn it to heat is the resistance of the wire. Since the resistance of the wire in a typical doublet antenna is very low, most of the power must be radiated. Making an antenna a non-resonant length does not change the resistance of the wire therefore it doesn't raise the amount of power disipated as heat by any significant amount.
Reply to a comment by : AD4U on 2007-02-23

Doing something to add 1 or 2 dB to your signal may not make much difference by itself. However if you have the $$ and the time and the expertise, making changes that add a dB here and a dB there and another dB somewhere else, collectively WILL make a noticeable difference. This is often what separates the BIG GUNS from the little pistols.
AA4PB2007-02-23
RE: Benchmarks
Speakers and audio amplfiers are quite different than antennas and RF. The wires connecting the speakers are very short in terms of the wavelength of the audio and they do not act as transmission lines. You don't have to deal with standing waves and reflected power on the speaker wires.

It is true however that maximum power is transferred from the source to the load when the load impedance matches the source impedance. That's akin to matching the antenna SYSTEM to the transmitter which is why matchboxes are often used. It doesn't relate to resonance of an antenna however.

Think of a matchbox as an output transformer on an amplifier. It matches the impedance of the speaker load to the impedance of the output tubes or transistors. Yes, transformers are still used in commercial audio amplifiers, primarily to match to a 70V distributed paging speaker system.
Reply to a comment by : AA4PB on 2007-02-23

Alan, I submit that the ends of a dipole (resonant or not) are ALWAYS open and ALWAYS high impedance. That is exactly what makes the feed impedance of a dipole change as you change its physical length. When each side of a dipole is an exact odd multiple of 1/4 wavelength long then the standing wave on the antenna transforms the high impedance at the end to a fairly low impedance at the center. If the antenna is some other (non-resonant) length then the standing wave transforms the high impedance at the end to some other impedance at the center. As long as you can match that impedance to the feed line you can transfer power into the antenna. If you can transfer power into an antenna then most of it (less the small I*R loss in the resistance of the wire) will be radiated. An antenna has basically two ways to get rid of the power that gets applied to it. Either is is radiated or it is turned to heat. The only thing that can turn it to heat is the resistance of the wire. Since the resistance of the wire in a typical doublet antenna is very low, most of the power must be radiated. Making an antenna a non-resonant length does not change the resistance of the wire therefore it doesn't raise the amount of power disipated as heat by any significant amount.
Reply to a comment by : AD4U on 2007-02-23

Doing something to add 1 or 2 dB to your signal may not make much difference by itself. However if you have the $$ and the time and the expertise, making changes that add a dB here and a dB there and another dB somewhere else, collectively WILL make a noticeable difference. This is often what separates the BIG GUNS from the little pistols.
W8JI2007-02-23
RE: Benchmarks
Effective radiated power in the desired optimum direction or directions on the desired frequency is the ONLY thing that matters at the desired receiver when looking at the transmitting antenna. This is determined by gain and polarization at a desired angle and direction and power applied to the antenna.

At the receiver the ratio of response to unwanted signals (including noise) vs. response to desired signals is all that matters. The only attention to gain or power losses is that external noise has to set the system noise level.

It's VERY important to know this, because many people falsely think increasing antenna gain will bring an equal dividend on receiving and transmitting and wrongly cite the "reciprocity" rule as proof.

Antennas do NOT offer the same performance advantage between receiving and transmitting, as a matter of fact outside of very high frequencies they almost never do.

Reply to a comment by : W4LGH on 2007-02-22

To W4LGH: You Wrote: Now with a call like this, this guy is at least an "ADVANCED" class if not an "EXTRA" class, what I said is basic ....................................................... K9IUQ says Perhaps you could explain to me WHY Extra class hams with egos ALWAYS try to belittle a ham that is not an Extra? I have NEVER been able to figure this one out? This fellow could be a TECH and BE twice as intelligent as you. Ham Class does not relate to intelligence or knowledge. ..................................................... I guess you missed that one too! An AA call is either an ADVANCED or EXTRA class license, so I was picking on the ADVANCED/EXTRA class, and not the Tech. Someone who holds these class license should understand resonance. Stop reading what you want it to say and read what I said. I am done here! No hope....
Reply to a comment by : K9IUQ on 2007-02-22

To W4LGH: You Wrote: Now with a call like this, this guy is at least an "ADVANCED" class if not an "EXTRA" class, what I said is basic ....................................................... K9IUQ says Perhaps you could explain to me WHY Extra class hams with egos ALWAYS try to belittle a ham that is not an Extra? I have NEVER been able to figure this one out? This fellow could be a TECH and BE twice as intelligent as you. Ham Class does not relate to intelligence or knowledge. ..................................................... W4LGH Wrote:I give up here, this guy just isn't with the program...A dummy LOAD is NOT resonate, it is a resistive LOAD designed to burn up the power by turning it into HEAT! Thats why they call it a dummy LOAD! (key word there is LOAD) ...................................................... K9IUQ says Thank goodness I never had your program. From the ARRL handbook - The Key word here is LOAD as in antenna load. To a transmitter an antenna presents a Load. "In practice,real antenna loads are seldom purely resistive or exactly 50 ohms; they often exhibit SWRs of 2:1 or greater on some frequencies." .................................................... And Posted By N3OX Respectfully, W4LGH, I would like to point out that you are the one muddying the waters about a *resonant antenna* and its radiating effectiveness. It is not true that antenna element resonance has anything to do with coupling power into the electromagnetic field around the antenna. ............ And K3AN posted For the last time, there is nothing magical about resonant antennas. ......................................................... K9IUQ Says; N3OX and K3AN, That was like a breath of fresh air, some Hams do "get it". And If you want useful, accurate information on antennas,you won't find it on ham forums, go to respected people like the L.B. Cebik web site www.cebik.com. and Beg, Borrow, or Steal a copy of Reflections, one of the most readable tomes on Antennas, SWR and Ham Myths. K9IUQ
AA4PB2007-02-23
RE: Benchmarks
Alan, I submit that the ends of a dipole (resonant or not) are ALWAYS open and ALWAYS high impedance. That is exactly what makes the feed impedance of a dipole change as you change its physical length. When each side of a dipole is an exact odd multiple of 1/4 wavelength long then the standing wave on the antenna transforms the high impedance at the end to a fairly low impedance at the center. If the antenna is some other (non-resonant) length then the standing wave transforms the high impedance at the end to some other impedance at the center. As long as you can match that impedance to the feed line you can transfer power into the antenna. If you can transfer power into an antenna then most of it (less the small I*R loss in the resistance of the wire) will be radiated.

An antenna has basically two ways to get rid of the power that gets applied to it. Either is is radiated or it is turned to heat. The only thing that can turn it to heat is the resistance of the wire. Since the resistance of the wire in a typical doublet antenna is very low, most of the power must be radiated. Making an antenna a non-resonant length does not change the resistance of the wire therefore it doesn't raise the amount of power disipated as heat by any significant amount.
Reply to a comment by : AD4U on 2007-02-23

Doing something to add 1 or 2 dB to your signal may not make much difference by itself. However if you have the $$ and the time and the expertise, making changes that add a dB here and a dB there and another dB somewhere else, collectively WILL make a noticeable difference. This is often what separates the BIG GUNS from the little pistols.
KC8QFP2007-02-23
RE: Benchmarks
PS: An after-thought...
using traps to me is akin to using a five watt voicecoil on a 200 watt amplifier. It works OK until you crank up the power, then it's fried! You can play with the numbers, but I try to find the most efficient antenna to do the job with my transmitter - a matched system, rather than a "matchbox and traps". Using caps and coils as filters would be like crossovers for woofers and tweeters. Funny thing, I prefer to bi-amp for the different freqs, a speaker per amp - this would be like using a separate antenna per band rather than a multi-band antenna (multi-band antenna is like a three way speaker system with crossovers, instead of a separate speaker, each having its own amp). Comparring AF and RF, may be a better way to understand.

Don
Reply to a comment by : KC8QFP on 2007-02-23

I kind of think of matching antennaes like matching speakers on my HIFI system (another hobby I really enjoy besides ham radio - hihi). Eight ohms, one speaker, two speakers, three, four etc., there are a number of ways to match the speakers (series, parellel, series/parellel). If you use sixteen ohms, four ohms, two ohms, and so forth, they will work on an amplifier that is made for eight ohms, but... kick up the power and see how hot the amp gets? The most efficient radiation from the speaker system depends on it matching its amplifier. A tuner or matchbox reminds me of using an LPad to control the volume of a speaker, it does not radiate any sound, but warms up and keeps a match on the amp whilst it turn down the loudness, not the best way to do it. The standard could be the eight ohm voice coil, as it is the dipole. If you have a two ohm speaker, an Lpad would be a way to match it to eight owm's. I like to KISS, and perhaps using speakers would simplify the discussion for the new guys. Don PS: Some of the new guys used the coat hanger as their antenna standard to compare with!!! HIHI!
Reply to a comment by : KE4ZHN on 2007-02-23

Ah yes, the famous "it has to be cut to the band" crap. Pure unadulterated bull**it!! Tell all the broadcast engineers at every AM broadcast station in the world and every shortwave broadcast engineer in the world that their doing it all wrong by using nonresonant antennas. And then be prepared to be made a fool of by them when they laugh in your face and explain why your full of crap. If they can stop laughing long enough to. The same way I laugh when I hear this nonsense time and time again repeated on the air. Especially when I work stations many of them cant even hear on their so called resonant antennas cut to the band. I love my 600 ohm ladderline fed 80 mtr. doublet. Since these have been around since the 20`s and 30`s I guess they just dont work at all. Its such a lousy antenna that its been around for around 80 years and yet they still dont work worth a crap. Amazing isnt it? Yeah, and those nonresonant rhombics VOA uses sure are pi$$ weak. Maybe thats why they have to run 500kw into the arrays just to make up for all those losses? lol The engineers at VOA must have to hose down the antennas and matching networks to cool the heat from the excessive losses those lousy nonresonant antennas generate. Yeah....right! Its going to take me a week to shovel all the BS out of my shack after reading some of this nonsense.
K9IUQ2007-02-23
Benchmarks
This has been a most intersting discussion that can be summed up in a few quotes:

N4KC -- "I'd suggest you visit http://www.w2du.com/ and check out some of the material there. As noted by others, W2DU, Walter Maxwell, has done more studying of the resonant/non-resonant antenna question than we could all do in a hundred years,

AA4PB --"There is nothing magic about resonance. Resonance simply means that there is no inductive reactance in the load, only resistance.

A non-resonant antenna element can be every bit as efficient as a resonant antenna element, sometimes more. The question is the ability to efficiently couple power from the transmitter into the antenna.

K9IUQ --"Antenna Discussions like this always show me how little Hams know about antennas. The same un-truths I hear on the air show up in print. If hams would only READ the antenna literature available the untruths would not persist.After 46 years of listening to and reading online about Antennas, I have concluded that most Hams know Little Antenna theory. It aint Voo-doo or magic fellows, antenna perfomance and theory has been well established. we only have to get our information from respected books - NOT other Hams or eham discussions.

N3OX --"Respectfully, W4LGH, I would like to point out that you are the one muddying the waters about a *resonant antenna* and its radiating effectiveness.

It is not true that antenna element resonance has anything to do with coupling power into the electromagnetic field around the antenna.

W6TH --"This is no myth, but the truth.

A resonant antenna and a non resonant antenna are both efficient antennas; non are better than the other, each has its own purpose for use.

W8WZ --"Some Good points are made here - but one that is over looked in the article is that an antenna does NOT have to be resonant to have positive gain.
Classic wire designs such as the Zepp, Extended Double Zepp, and Sterba Curtain are not resonant and will need to have some sort of antenna coupler to be used with a transmitter that is looking for a 50 ohm match. Nevertheless, when matched to the Xmtr with the transmatch - they work very well and exhibit high amounts of gain.


And perhaps the quote that sums it up best

W6TH --"W4LGH Alan,
I've heard enough of your bullshit, enough is enough.


STAN K9IUQ







KC8QFP2007-02-23
RE: Benchmarks
I kind of think of matching antennaes like matching speakers on my HIFI system (another hobby I really enjoy besides ham radio - hihi). Eight ohms, one speaker, two speakers, three, four etc., there are a number of ways to match the speakers (series, parellel, series/parellel). If you use sixteen ohms, four ohms, two ohms, and so forth, they will work on an amplifier that is made for eight ohms, but... kick up the power and see how hot the amp gets? The most efficient radiation from the speaker system depends on it matching its amplifier. A tuner or matchbox reminds me of using an LPad to control the volume of a speaker, it does not radiate any sound, but warms up and keeps a match on the amp whilst it turn down the loudness, not the best way to do it. The standard could be the eight ohm voice coil, as it is the dipole. If you have a two ohm speaker, an Lpad would be a way to match it to eight owm's. I like to KISS, and perhaps using speakers would simplify the discussion for the new guys.

Don

PS: Some of the new guys used the coat hanger as their antenna standard to compare with!!! HIHI!
Reply to a comment by : KE4ZHN on 2007-02-23

Ah yes, the famous "it has to be cut to the band" crap. Pure unadulterated bull**it!! Tell all the broadcast engineers at every AM broadcast station in the world and every shortwave broadcast engineer in the world that their doing it all wrong by using nonresonant antennas. And then be prepared to be made a fool of by them when they laugh in your face and explain why your full of crap. If they can stop laughing long enough to. The same way I laugh when I hear this nonsense time and time again repeated on the air. Especially when I work stations many of them cant even hear on their so called resonant antennas cut to the band. I love my 600 ohm ladderline fed 80 mtr. doublet. Since these have been around since the 20`s and 30`s I guess they just dont work at all. Its such a lousy antenna that its been around for around 80 years and yet they still dont work worth a crap. Amazing isnt it? Yeah, and those nonresonant rhombics VOA uses sure are pi$$ weak. Maybe thats why they have to run 500kw into the arrays just to make up for all those losses? lol The engineers at VOA must have to hose down the antennas and matching networks to cool the heat from the excessive losses those lousy nonresonant antennas generate. Yeah....right! Its going to take me a week to shovel all the BS out of my shack after reading some of this nonsense.
W8JI2007-02-23
RE: Benchmarks
by W4LGH on February 23, 2007

And in another portion it talks about an antenna working better if it is resonate...
"Antenna design is very complex and requires a lot of time and study to master. However, any antenna will have to oscillate charged particles in order to transmit radio signals and will tend to do this best if the antenna is "resonating".>>>

Well it might talk about it and say that, but whoever wrote it is wrong unless we use the word "tend" very loosely.

The only thing not being "resonant" does is create a reactive termination for a feedline. That might increase feedline losses. It does NOT affect the abilitly to radiate. The efficiency of the antenna is a function of normalized resistances, not reactances.

<<
RF travels on a conductor known as the SKIN EFFECT, this is why alumium works as well as copper for an antenna, but we ALL know alumium has more resistance than copper, and I would be willing to say I bet that the nichrome would probably work just fine too, since the RF travels down the surface, and not thru the wire. Interesting experiment to try, now where does one fine a 100' of nichrome wire affordable!>>


That's not true. Aluminum works ONLY about as well as copper because the resistance is not that much different than copper. It has little to nothing to do with skin depth.

Nichrome would make a terrible antenna if the antenna is physically long and has a reasonably low radioation resistance. So would steel.

73 Tom
Reply to a comment by : NT4XT on 2007-02-23

" The fact is (contrary to popular belief), antennas are NOT reciprocal in their transmit verses receive performance." And somewhere further down the line in the thread it was mentioned that radiation patterns obey reciprocity. However, that is not what was stated by the author, the word used was "performance," as in, "NOT reciprocal in TX vs RX..." Given the factor of S/N, I agree with the author of the article. At a prior QTH, I had a 40m GP and a low horizontal dipole (up 30 feet). On paths from Atlanta to the west coast, I often would TX on the GP and RX on the dipole. The vertical picked up more locally generated industrial type noise, especially when the weather was misty and the neighborhood telephone pole powerline support points, and step down transformer connections would start buzzing. The difference as far as relative readings, could be as much as 2 s-units on RX between the two antennas. To clarify, in TX, my vertical would often make signal about 2 S-units higher in CA, my dipole on TX about 2 S-units lower. In RX in Atlanta, the vertical might be reciprocal, but the CA signal is painful to differentiate due to higher noise level. The dipole, often would result in easier copy, much more enjoyable. That, is a difference in performance, whatever the reason(s), of which radiation pattern is a factor, but not- the only factor. Sometimes I'll have a conversation with someone 1 or 2 states (as defined by geopolitical boundries), away. The other station signal might register s8, on my rig, my signal s7 or s6, the other station vertical, my station horizontal. Our power levels the same. In such cases I don't worry something must be wrong, I figure it would be parity if I was we were both vertical or both horizontal. I always heard SWR means not everything when I came back into the hobby 5 years ago. Makes sense, we've all heard, a dummy load most often returns a 1.1:1 or better, SWR. But in the real world, this really hit home and was illustrated to me, the day my coax fed dipole developed a short at the center insulator. My wonderkind tuner was able to make my rig see a 1.4:1 SWR, with full 80-100W getting absorbed in a couple places. After about the 4th or 5th rag chew QSO like this, and my RST's coming back were quite dismal, I finally decided to check into things, to discover that for the most part my antenna had become some length of coax shorted out at the far end. I could really tell, when the person I called was looking for a decent chat, but would end it sooner than what was probably normal. All that being said, (whew!), for good reason, radiation patterns are bench marks that we use to determine performance, theoretical and real world. It could be important to know, that propagation plays a major factor in perceived and measured performance. There have been times when propagation seems one way. If you care to be tactful, you can always blame propagation, LOL. If the other person's antenna system has issues, pretty soon they'll figure it out, when they realize that for them propagation always seems to be in the crapper, even while it seems okay for everyone else, LOL! I know I did figure this out this way, even when no one told me, Hey Old Man, your signal bites the weeny, you might wanna check your antenna. Great article timely submitted, given the likely wave of impending first-time HFers that ought to be hitting the bands any time now!
AD4U2007-02-23
Benchmarks
Doing something to add 1 or 2 dB to your signal may not make much difference by itself. However if you have the $$ and the time and the expertise, making changes that add a dB here and a dB there and another dB somewhere else, collectively WILL make a noticeable difference. This is often what separates the BIG GUNS from the little pistols.
AA4PB2007-02-23
RE: Benchmarks
Alan DID qualify his statement by saying that antennas are not "reciprocal in performance". That is a true statement (at least part of the time). Technical textbooks however use the term "reciprocal" to mean gain and radiation pattern rather than S/N ratio performance. Antennas ARE reciprocal in this common usage of the term.

The point is that one antenna can be better than another for transmit yet worse than the other on receive. I don't think anyone is disputing that point. When you use the term "reciprocal" to describe it however you risk being judged as rewriting the textbooks because textbooks will tell you that antennas are reciprocal :-)

When you start talking about S/N ratio then you introduce a variable that is difficult to control. Noise levels change from time to time, place to place, and with different installations of the same antenna.
Reply to a comment by : KE4ZHN on 2007-02-23

Ah yes, the famous "it has to be cut to the band" crap. Pure unadulterated bull**it!! Tell all the broadcast engineers at every AM broadcast station in the world and every shortwave broadcast engineer in the world that their doing it all wrong by using nonresonant antennas. And then be prepared to be made a fool of by them when they laugh in your face and explain why your full of crap. If they can stop laughing long enough to. The same way I laugh when I hear this nonsense time and time again repeated on the air. Especially when I work stations many of them cant even hear on their so called resonant antennas cut to the band. I love my 600 ohm ladderline fed 80 mtr. doublet. Since these have been around since the 20`s and 30`s I guess they just dont work at all. Its such a lousy antenna that its been around for around 80 years and yet they still dont work worth a crap. Amazing isnt it? Yeah, and those nonresonant rhombics VOA uses sure are pi$$ weak. Maybe thats why they have to run 500kw into the arrays just to make up for all those losses? lol The engineers at VOA must have to hose down the antennas and matching networks to cool the heat from the excessive losses those lousy nonresonant antennas generate. Yeah....right! Its going to take me a week to shovel all the BS out of my shack after reading some of this nonsense.
KE4ZHN2007-02-23
Benchmarks
Ah yes, the famous "it has to be cut to the band" crap. Pure unadulterated bull**it!! Tell all the broadcast engineers at every AM broadcast station in the world and every shortwave broadcast engineer in the world that their doing it all wrong by using nonresonant antennas. And then be prepared to be made a fool of by them when they laugh in your face and explain why your full of crap. If they can stop laughing long enough to. The same way I laugh when I hear this nonsense time and time again repeated on the air. Especially when I work stations many of them cant even hear on their so called resonant antennas cut to the band. I love my 600 ohm ladderline fed 80 mtr. doublet. Since these have been around since the 20`s and 30`s I guess they just dont work at all. Its such a lousy antenna that its been around for around 80 years and yet they still dont work worth a crap. Amazing isnt it? Yeah, and those nonresonant rhombics VOA uses sure are pi$$ weak. Maybe thats why they have to run 500kw into the arrays just to make up for all those losses? lol The engineers at VOA must have to hose down the antennas and matching networks to cool the heat from the excessive losses those lousy nonresonant antennas generate. Yeah....right! Its going to take me a week to shovel all the BS out of my shack after reading some of this nonsense.
NT4XT2007-02-23
Benchmarks
" The fact is (contrary to popular belief), antennas are NOT reciprocal in their transmit verses receive performance."
And somewhere further down the line in the thread it was mentioned that radiation patterns obey reciprocity.
However, that is not what was stated by the author, the word used was "performance," as in, "NOT reciprocal in TX vs RX..."

Given the factor of S/N, I agree with the author of the article.
At a prior QTH, I had a 40m GP and a low horizontal dipole (up 30 feet).
On paths from Atlanta to the west coast, I often would TX on the GP and RX on the dipole.

The vertical picked up more locally generated industrial type noise, especially when the weather was misty and the neighborhood telephone pole powerline support points, and step down transformer connections would start buzzing.
The difference as far as relative readings, could be as much as 2 s-units on RX between the two antennas.
To clarify, in TX, my vertical would often make signal about 2 S-units higher in CA, my dipole on TX about 2 S-units lower. In RX in Atlanta, the vertical might be reciprocal, but the CA signal is painful to differentiate due to higher noise level. The dipole, often would result in easier copy, much more enjoyable. That, is a difference in performance, whatever the reason(s), of which radiation pattern is a factor, but not- the only factor.

Sometimes I'll have a conversation with someone 1 or 2 states (as defined by geopolitical boundries), away. The other station signal might register s8, on my rig, my signal s7 or s6, the other station vertical, my station horizontal. Our power levels the same. In such cases I don't worry something must be wrong, I figure it would be parity if I was we were both vertical or both horizontal.

I always heard SWR means not everything when I came back into the hobby 5 years ago. Makes sense, we've all heard, a dummy load most often returns a 1.1:1 or better, SWR. But in the real world, this really hit home and was illustrated to me, the day my coax fed dipole developed a short at the center insulator. My wonderkind tuner was able to make my rig see a 1.4:1 SWR, with full 80-100W getting absorbed in a couple places. After about the 4th or 5th rag chew QSO like this, and my RST's coming back were quite dismal, I finally decided to check into things, to discover that for the most part my antenna had become some length of coax shorted out at the far end. I could really tell, when the person I called was looking for a decent chat, but would end it sooner than what was probably normal.

All that being said, (whew!), for good reason, radiation patterns are bench marks that we use to determine performance, theoretical and real world.
It could be important to know, that propagation plays a major factor in perceived and measured performance.
There have been times when propagation seems one way. If you care to be tactful, you can always blame propagation, LOL. If the other person's antenna system has issues, pretty soon they'll figure it out, when they realize that for them propagation always seems to be in the crapper, even while it seems okay for everyone else, LOL! I know I did figure this out this way, even when no one told me, Hey Old Man, your signal bites the weeny, you might wanna check your antenna.

Great article timely submitted, given the likely wave of impending first-time HFers that ought to be hitting the bands any time now!
W4LGH2007-02-23
RE: Benchmarks
Dan N3OX...wrote~"I'm not sure where you're coming from on a lot of this stuff."~

Dan..I posted 2 links in earlier posts that explain this. I also posted a section of one of the links, which I will again, the key words are "electrically OPEN and electrically SHORTED", not physcial.
--------READ BELOW--------
The very slight motion of electrons up and down an antenna is enough to cause electromagnetic waves to radiate out the sides of the antenna at the same frequency as the variable voltage applied to it. These are used for transmitting radio and television signals as well as other forms of wireless communication.

Like sound, when electrical waves at a defined frequency hit the end of an antenna they are reflected backwards and form a standing wave in the antenna. Antenna waves move at the speed of light (3 x 10 8 m/s) and so the travel time from one end of the antenna to the other is pretty quick.

The electrical waves created on antennas typically have a fixed wavelength. If the length of the antenna is wisely chosen it's possible to make it resonate. The free end of an antenna acts like an open circuit. Voltage drop is maximum across an open circuit and zero across a short circuit. Hence the end of an antenna forms an anti-node or area of maximum voltage or e-field strength. A node is a point which has zero e-field. The distance between an anti-node and node is a quarter of a wavelength."

And in another portion it talks about an antenna working better if it is resonate...
"Antenna design is very complex and requires a lot of time and study to master. However, any antenna will have to oscillate charged particles in order to transmit radio signals and will tend to do this best if the antenna is "resonating".
---------END---------

And to the guy who is taking about using nichrome wire..then I guess we should all be using GOLD wire?
RF travels on a conductor known as the SKIN EFFECT, this is why alumium works as well as copper for an antenna, but we ALL know alumium has more resistance than copper, and I would be willing to say I bet that the nichrome would probably work just fine too, since the RF travels down the surface, and not thru the wire. Interesting experiment to try, now where does one fine a 100' of nichrome wire affordable!

It is certainly clear that just about everyone has their "OWN" ideas on how antennas work, and if it works for you, then so be it! Enjoy playing radio, and bring a friend into the hobby!

73 de W4LGH - Alan
http://www.w4lgh.com
Reply to a comment by : KW6LA on 2007-02-23

Alan you are right on the money with your timely post. I worked a Ham on 20 meters last week and he was running a 80 meter vee dipole @ 20 yes 20 ft. I tried to be polite and asked why only 20 feet and his reply was-- works just great ! ! I asked if he has used any other antennas to make that judgment #@$... reply -- N O it works just fine. By then I was getting a little angry and told him that I was running a half / gallon of power into a 3 element Yagi @ 44 feet. This will give me back an S 9 report from most stations if the band is in good shape . Notice that I gave you a 5/7 and you copy me 5/5 …Humm ? This happens a lot and most times I can guess that the other station is using a less than desirable antenna.This is not to say all hams have to run the Big Gun / gain antennas, but why some hams put $ 8,000.00 into a radio, $500 for the tuner and end up with a G5RV @ 20 feet is beyond me. I only hope more Hams read and benefit from the information written by Alan an others on E-Ham. Great job guys and for the others ##### learn from them, save money and take you wife out to dinner. 73's Tony
W9PMZ2007-02-23
RE: Benchmarks
"The fact is (contrary to popular belief), antennas are NOT reciprocal in their transmit verses receive performance."

Reciprocity is an attribute, based on the radiation pattern of a specific antenna which is the same for RX and TX for that specific antenna and it is a fact not a myth.

Every different antenna and installation has a different radiation pattern. Therefore different antennas have different radiation patterns.

The point should be stated that different antennas have different radiation patterns and therefore in specific instances a specific antenna is a better RX (or TX) antenna than another specific antenna. And Alan is 100% correct in this assummption.

But the reference to reciprocity should not have been used in this example.

73,

Carl - W9PMZ
Reply to a comment by : KW6LA on 2007-02-23

Alan you are right on the money with your timely post. I worked a Ham on 20 meters last week and he was running a 80 meter vee dipole @ 20 yes 20 ft. I tried to be polite and asked why only 20 feet and his reply was-- works just great ! ! I asked if he has used any other antennas to make that judgment #@$... reply -- N O it works just fine. By then I was getting a little angry and told him that I was running a half / gallon of power into a 3 element Yagi @ 44 feet. This will give me back an S 9 report from most stations if the band is in good shape . Notice that I gave you a 5/7 and you copy me 5/5 …Humm ? This happens a lot and most times I can guess that the other station is using a less than desirable antenna.This is not to say all hams have to run the Big Gun / gain antennas, but why some hams put $ 8,000.00 into a radio, $500 for the tuner and end up with a G5RV @ 20 feet is beyond me. I only hope more Hams read and benefit from the information written by Alan an others on E-Ham. Great job guys and for the others ##### learn from them, save money and take you wife out to dinner. 73's Tony
KW6LA2007-02-23
Benchmarks
Alan you are right on the money with your timely post. I worked a Ham on 20 meters last week
and he was running a 80 meter vee dipole @ 20 yes 20 ft. I tried to be polite and asked why only
20 feet and his reply was-- works just great ! ! I asked if he has used any other antennas to make that
judgment #@$... reply -- N O it works just fine. By then I was getting a little angry and told him that I
was running a half / gallon of power into a 3 element Yagi @ 44 feet. This will give me back an S 9 report
from most stations if the band is in good shape . Notice that I gave you a 5/7 and you copy me 5/5 …Humm ?

This happens a lot and most times I can guess that the other station is using a less than desirable
antenna.This is not to say all hams have to run the Big Gun / gain antennas, but why some hams put
$ 8,000.00 into a radio, $500 for the tuner and end up with a G5RV @ 20 feet is beyond me. I only
hope more Hams read and benefit from the information written by Alan an others on E-Ham. Great job
guys and for the others ##### learn from them, save money and take you wife out to dinner.

73's Tony
W8WZ2007-02-23
RE: No Myth
Some Good points are made here - but one that is over looked in the article is that an antenna does NOT have to be resonant to have positive gain.

Classic wire designs such as the Zepp, Extended Double Zepp, and Sterba Curtain are not resonant and will need to have some sort of antenna coupler to be used with a transmitter that is looking for a 50 ohm match. Nevertheless, when matched to the Xmtr with the transmatch - they work very well and exhibit high amounts of gain.

Other antennas like the Fritzel will be technically resonant on many frequencys but with little or no gain.

Also - in Amateur practice whener DB is used it is assumed that it is DBd - at least according to the handbook.
Reply to a comment by : W4LGH on 2007-02-22

W6TH Vito wrote.. ~"W4LGH Alan, I've heard enough of your bullshit, enough is enough."~ Well Mr Vito...That certainly was an educated response! I have seen it all in my career, from a 5 gallon bucket of dirt in a guys trunk, because the instructions said "This wire needs to go to EARTH ground", to a station engineer who wouldn't let anyone install any antennas upside down on his tower because he said, RF would leak out. I guess some people take things to litteral, and some don't take it litteral enough. A lot of good info in this thread, but again it goes to show you can not POST a good article here on eHam, no matter what, people will try to tear it apart. No one understands friendly debate. 73 de W4LGH - Alan
Reply to a comment by : W6TH on 2007-02-22

. W4LGH Alan, I've heard enough of your bullshit, enough is enough. W6TH .:
Reply to a comment by : W6TH on 2007-02-22

. Frequency = 1 divided by time. Time is relevant. Known as the Black Hole. No Myth. .:
Reply to a comment by : N3OX on 2007-02-22

"But the tuner was at the antenna feed point, matching the antenna impedance to the radio, it worked, and I certainly didn't have extra power to spare, but it would have worked BETTER, had the wire been resonant on the frequency I was using" Untrue.
Reply to a comment by : N3OX on 2007-02-22

W4LGH: The excerpt you quoted from that page explains that a center fed antenna has the lowest possible impedance when it's half-wave resonant (or three-halves or five halves, whatever); that is, if you fix the ***voltage*** you feed to an antenna, you'll get the most current, and therefore the biggest field, when it's an odd multiple of a half wave. If you force the same current in a similar, but nonresonant antenna, you get the same strength field (up to the antenna being a little bit shorter or longer which affects its gain in a minor fashion). If you had a magical transistor or tube that didn't care if the voltage was not in phase with the current and didn't care how high that voltage got, you would never have to match to a nonresonant antenna. We always say that we're "transforming the antenna impedance" with a network, but we could equally say "we're transforming the transmitter output up to a voltage with the proper phase to drive the a particular current into the antenna impedance" An article I found that's more precise: http://www.cv.nrao.edu/course/astr534/AntennaTheory.html There's a bunch of stuff later on that isn't particularly applicable to our current discussion, like the impedance of a black hole, but they do talk about reciprocity later on in the page. 73, Dan
Reply to a comment by : W6TH on 2007-02-22

. W4LGH We have been talking about transmitting antennas, I would like to know a specific purpose for using a non-resonant antenna on a transmitter. ..................................................... A long-wire antenna radiates more power in its most favorable direction than does a half wave resonant antenna in its most favorable direction. This power gain is secured at the expense of radiation in other directions. Would you like me to run some analytical Geometry for you? Maybe my math can convince you. Better yet, lets see what your math can do for me. 73, W6TH .:
Reply to a comment by : W4LGH on 2007-02-22

W6TH wrote..."This is no myth, but the truth. A resonant antenna and a non resonant antenna are both efficient antennas; non are better than the other, each has its own purpose for use." We have been talking about transmitting antennas, I would like to know a specific purpose for using a non-resonant antenna on a transmitter. If one truely understands resonance, I don't understand how anything can be as efficient as one that is resonant. And it is proven to you everytime you load up a transmitter. I certainly understand that weird things will work, but that doesn't make it so. I worked over 15 countries running 3 watts or less into a 50' wire fed at the end with an MFJ 16010 tuner. But the tuner was at the antenna feed point, matching the antenna impedance to the radio, it worked, and I certainly didn't have extra power to spare, but it would have worked BETTER, had the wire been resonant on the frequency I was using, certainly more efficient, as at resonancde the end of the wire looks like an open circuit, where as off resonance it begins to look like a short. 73 de W4LGH Alan http://www.w4lgh.com
Reply to a comment by : W6TH on 2007-02-22

. This is no myth, but the truth. A resonant antenna and a non resonant antenna are both efficient antennas; non are better than the other, each has its own purpose for use. W6TH .:
Reply to a comment by : WB2WIK on 2007-02-22

Not all solid state rigs reduce output power beginning at VSWR = 1.5. That is ultra conservative. The Ten Tec transceivers for years used a circuit breaker in the power supply to tell the transceiver when to "cut back power" due to high VSWR. They'd shut off! But until the breaker tripped, they'd keep transmitting. My Drake TR-7, by published specification, provides 90% of its full rated output power into a 2:1 VSWR and doesn't "fold back" to 50% (which is still about 75W output power) until VSWR = 5:1. That detail is listed here on the last page of the TR-7 brochure: http://wb4hfn.com/DRAKE/DrakeCatalogsBrochures/Brochure_TR7_04B.htm As such, the TR-7 hardly needs a tuner unless the user intends some pretty serious mismatches. Mine can easily produce 100W output power into a 3:1 mismatch, on any band. Without a tuner. It's largely a matter of "headroom" for the power amplifying devices selected. Margins include current, voltage and heat. One problem with a little rig like the FT-857 is its PA devices are small and its PA heatsink is *very* small, not capable of carrying much heat away from the devices, even with a fan. The TR-7 power amplifier heatsink alone (just the heatsink) is larger than the entire FT-857... WB2WIK/6
Reply to a comment by : K6HWH on 2007-02-22

"Every solidstate radio I have ever owned started shutting down power at a 1.5 swr." What about this? I have a Yaesu 857 that does indeed crank down transmit power if the SWR is the least bit off, ostensibly to prevent damage to the output transistors. If even a SWR of 5 does not diminish appreciable the antenna's ability to radiate, isn't this a mistake? Should I be looking for a way to defeat the 857's cautious approach to SWR?
Reply to a comment by : K3AN on 2007-02-22

This article is evidence that you can't determine the usefulness or accuracy of an article by the number of words. If you want useful, accurate information on antennas, please visit the L.B. Cebik web site www.cebik.com. For the last time, there is nothing magical about resonant antennas.
Reply to a comment by : N3OX on 2007-02-22

Respectfully, W4LGH, I would like to point out that you are the one muddying the waters about a *resonant antenna* and its radiating effectiveness. It is not true that antenna element resonance has anything to do with coupling power into the electromagnetic field around the antenna. The *REAL* part of the antenna impedance has two components, the radiation resistance and the loss resistance. That fraction of the power which is associated with "dissipation" in the radiation resistance is the power that gets radiated. The fraction associated with dissipation in the loss resistance goes up as heat. The power in the reactive part of the impedance is simply stored in fields around the antenna. That means that an antenna with an impedance of 70+j0 and one with an impedance of 70+j500 are radiating exactly the same amount of power if you can feed that power to them in the first place. You need to match the antenna system to the transmitter but resonance of the antenna element itself has nothing at all to do with the transfer of that power to radiating electromagnetic fields. If you are supplying 100W to the antenna, 100W minus the antenna losses is radiated, no matter whether or not the antenna element is resonant. 73, Dan
Reply to a comment by : W4LGH on 2007-02-22

You see, here we go again, a good article is written, it contains some great info. Some additional articles are written taken it a little further. Then come the people who truely do not understand what is being said, and either go on what they have seen, or what somebody else who truely doesn't understand told them. ==================================================== Now... AA4PB writes..."at resonance the antenna is inducing more power into the atmosphere ---------------------------------------------------- Can you point us to a definitive text that proves this, or even claims it to be true?" ==================================================== Now with a call like this, this guy is at least an "ADVANCED" class if not an "EXTRA" class, what I said is basic "Physics 101" Resonance is a common thread which runs through almost every branch of physics, and yet a lot of people have never studied it. Without resonance we wouldn't have radio, television, music, or swings on playgrounds, not to mention cool gismos like Tesla coils. Of course, resonance also has its dark side. It occasionally causes a bridge to collapse, a helicopter to fly apart, or other inconveniences. Unlike black holes, time travel, and quantum mechanics, resonance is common place and easy to observe. Yet, it is one of the most striking and unexpected phenomenon in all of physics. It is relative to everything. Here is a good link to read about it...hopefully it will explain.. http://www.intuitor.com/resonance/circuits.html Ever heard the term, "Dip the Plate" when tuning? Notice how the plate current drops but your output increases? Wonder why that is? Could it be your tank circuit has been tuned to resonance? Hmmm...your antenna is an extension of your tank circuit. And to K9IUQ...who wrote..."Also resonance of the SYSTEM has nothing to do with how well the antenna radiates. This is determined by MANY other factors. I have a wonderful Dummy load antenna under my desk that is resonant on all HF bands, however it doesnt seem to radiate very well since I haven't worked too many people with it."... I give up here, this guy just isn't with the program...A dummy LOAD is NOT resonate, it is a resistive LOAD designed to burn up the power by turning it into HEAT! Thats why they call it a dummy LOAD! (key word there is LOAD) Man..you guys say you want elmers, if you truely do not understand something, thats ok, there are people who do understand, and more than willing to help. 73 de W4LGH Alan http://www.w4lgh.com
Reply to a comment by : AA4PB on 2007-02-22

at resonance the antenna is inducing more power into the atmosphere ---------------------------------------------------- Can you point us to a definitive text that proves this, or even claims it to be true?
Reply to a comment by : K9IUQ on 2007-02-22

One TRUE statement was made, a RESONATE antenna will work BETTER than a NON_RESONATE antenna. People do NOT understand resonance ..................................................... The above is an false statement. An Antenna is resonant at ONLY ONE frequency. At any other frequency it is non-resonant. We all use non-resonant antennas (including you) on a daily basis. We make the antenna SYSTEM resonant with a tuner of one kind or another or live with SWR higher than 1:1. Agreed - the whole SYSTEM must be resonance -from the radio to the antenna. It makes little difference if the antenna itself is resonance or not.Many of the best performing wire antennas are non-resonant fed with open wire feeders and an antenna tuner. Also resonance of the SYSTEM has nothing to do with how well the antenna radiates. This is determined by MANY other factors. I have a wonderful Dummy load antenna under my desk that is resonant on all HF bands, however it doesnt seem to radiate very well since I haven't worked too many people with it. Please Pick Up an antenna Book like "Reflections" and learn the facts instead of trying to sell me 'some wonderful ocean front property in Arizona " K9IUQ
N3OX2007-02-22
RE: Benchmarks
"I think the 'I can work everything I can hear' comes from folks who live in a noisy RF enviornment"

That's probably some of it.

I think another aspect of it though is that active hams on average are probably within 10dB of power parity and in similar noise environments... if you're running a kilowatt and I'm running a hundred watts and we both have about the same level of noise, the percentage of time that I can hear you and you can't hear me is not especially large.

If I'm 30dB below your noise and you're 20dB below mine, we're not going to make it.

If you're 20dB above the noise and I'm 10dB above the noise, there's no problem.

It's the fluctuations around you being 5dB above the noise and me being 5dB below that are the problem... but if you're a DX station and I'm trying to call you, I can always hear you and eventually there's going to be a favorable upswing in the propagation, maybe only briefly, but enough to get me above your noise floor long enough to make the contact.

So, given about equal noise environments on both ends and normal amateur power levels, it's not too often that you can't "work what you can hear". You have to have very steady borderline conditions to not be able to make a contact with a station you can copy clearly, if you don't have drastically different power levels and noise situations.

If you live somewhere super quiet and you work QRP, well, you're certainly not going to work what you can hear.

I've lived and operated DX in noisy places and quiet, and it's rarely the case that I can't work what I can hear with my hundred watts. You're totally right about it being easy to work a station that's over your S7 noise, but I've found it to be more or less true even from a quiet location, just because the band can really change a lot more than the maybe 20dB disadvantage that a 100W + dipole station has versus a kilowatt and large beam.

Dan
Reply to a comment by : former_AE6CP_LH on 2007-02-22

I think the 'I can work everything I can hear' comes from folks who live in a noisy RF enviornment. If you have an S-7 noise floor. Chances are youre only going to hear either 'big guns' or people who have a very good propagation path to you. And chances are, those two types of stations will be able to hear you too. I've been that ham. When twenty meters was wide open, I might hear 15 or 20 stations on the phone band when I knew there were probably hundreds way under the noise floor.
former_AE6CP_LH2007-02-22
Benchmarks
I think the 'I can work everything I can hear' comes from folks who live in a noisy RF enviornment. If you have an S-7 noise floor. Chances are youre only going to hear either 'big guns' or people who have a very good propagation path to you. And chances are, those two types of stations will be able to hear you too.

I've been that ham. When twenty meters was wide open, I might hear 15 or 20 stations on the phone band when I knew there were probably hundreds way under the noise floor.

N3OX2007-02-22
RE: Benchmarks
"If you go by what everyone else is saying here, one could put up any random length dipole and use it for all bands 160m thur 1200 mhz., and one could, but at what loss or effeciency? "

If you have lossless matching networks and superconducting wire, no loss at all. None. Zero. Zilch. Zip. Nada. You could radiate every last milliwatt of your transmitter power on every single frequency from DC to daylight (ok, maybe THz).

This is my point. Losses come from loss resistance, not from lack of resonance.

Let's enter a contest sometime. You get a resonant 20m dipole made with #30 nichrome wire. I get a #14 copper wire doublet that's about 40 feet long. My antenna is far from resonance, with an impedance of 120+j310 at 14MHz. Yours is trimmed carefully to resonance in the middle of 20m. I get a homebrew tuner at the antenna feedpoint.

Who wins the contest, provided that your antenna doesn't melt ;-)

Dan
Reply to a comment by : N3OX on 2007-02-22

"When a dipole antenna is resonant, the ends become electrically open, thus allowing the antenna to transfer the most energy." What are you talking about? The ends of the antenna are ALWAYS electrically open. They are not connected to anything. "it is now out of resonance, and the ends become electrically shorted, thus producing standing waves or reflected power back thru the system. Where does this non-radiated power go, you ask? Up in heat, which is a completely different spectrum." Reflections are caused by the antenna ends becoming short circuits? To what? The earth? Each other? It is true that you get reflected power on the transmission line, unless, of course, you put a matching network right at the antenna like I like to do. There is a small loss in the matching network. Most people don't like to do that but the ones who are paying attention use ladderline at least. - - - - - - I'm not sure where you're coming from on a lot of this stuff. Dan
Reply to a comment by : W4LGH on 2007-02-22

AA4PB wrote..."Alan, yes I am an Extra since 1995. My first class radiotelephone, ship radar endorsement and all amateur exams except the Extra were taken in front of an FCC examiner. Since 1963 I've made my living in electronics so I might have just a little experience. I submit that you are absolutely wrong in your assertion that a resonant antenna element length radiates more of the applied signal than a non-resonant length. A non-resonant length will radiate all of the power applied to it (less any losses) just as well as a resonant length. If this is not so then please explain where the power that is applied to the element but not radiated goes. If, instead of attacking people's intelligence, you will take the time to review the text books I believe you'll find that what many people here are telling you is indeed true." ========= Well then we have many things in common, including the same licenses and all of mine were taken in front of an FCC rep, and that I too have been professionally involved in electronics since 1963. I have a sneaky feeling that this discussion is going the same way as a previous thread on here where everyone was using CW as Morse Code, when in fact CW is an un-modulated carrier and MOrse code was the intellengence on the CW. Because of so many years of people using CW as meaning using Morse code, that no one understood the difference. When a dipole antenna is resonant, the ends become electrically open, thus allowing the antenna to transfer the most energy. IE: a dipole cut for 7100khz, will operate at it most efficency when a freq of 7100khz is applied to it. Now if you apply a freq of 7500Khz on this same antenna, it is now out of resonance, and the ends become electrically shorted, thus producing standing waves or reflected power back thru the system. Where does this non-radiated power go, you ask? Up in heat, which is a completely different spectrum. Now if you want to include this radiation along with the main signal radiation, then you can say a non-resonate antenna will radiate all its energy. However when I say a resonate antenna is more effecient, I am saying it is radiating the MOST USEABLE RF energy from the main source. The differences may be very minor, but measurable non the less. If you go by what everyone else is saying here, one could put up any random length dipole and use it for all bands 160m thur 1200 mhz., and one could, but at what loss or effeciency? To simple say a non-resoante antenna will radiate as much energy as a resonate one simple goes against the laws of physics, and we'd all have one antenna for all frequencies. There simply are no MAGIC BLACK BOX one antenna works all frequencies! Either I am missing something here or a lot of other are missing something, maybe a failure to communicate or lost in the translations. 73 de W4LGH - ALan http://www.w4lgh.com
Reply to a comment by : KA0GKT on 2007-02-22

Carl - W9PMZ wrote: "antennas are NOT reciprocal in their transmit verses receive performance" Rewriting text books? Most antenna books that I have been privy to read starts the treatment of antennas by making a statement: "In this section we show that the radiation pattern of an antenna is the same whether it is used as a transmitting antenna or a receiving antenna. Reciprocity allows the calculation or measurement of an antenna pattern in either the transmit or receive case." (from Antenna Theory and Design by Stutzman and Thiele, page 40) Propagation at HF makes the antennas properties (height, length, etc) the issue, but the antenna still obeys reciprocity. Antennas do indeed behave differently on receive than on transmit. The phenominon is called the Dipole factor and it has been documented since the time when the current NTSC TV channels were being laid out in the late 1940s. Since this was calculated for TV, the benchmark for the dipole factor is in the range of 47 MHz which was the original channel One. As the operating frequency increases, for a fixed signal density, the voltage at the terminals of a properly terminated dipole will decrease. For instance, with a 1 micro-volt/meter field strength, the voltage at the terminals of a dipole cut to 30 MHz will be 1.59 micro-volts. At a dipole cut for 50 MHz it will be .955 micro-volts; a 144 MHz dipole will have .332 micro-volts; a 220 MHz dipole will have .215 micro-volts; at 432 there will be .11 micro-volts. The formula to calculate dipole factor is: Et = Ef x ((300/F)/(2 x Pi)) Where: Et = RF voltage across the properly terminated terminals of the dipole. Ef = Field Strength in Volts per Meter F = Frequency in MHz Pi = 3.142 So, you can see that in order for a 70 cm antenna to provide the same level of reception as a 6 m dipole, the 70 cm antenna must have a 9.35 dBd gain. It must be noted that the dipole factor is only a factor for reception, when transmitting, a dipole is a dipole is a dipole. 73 DE KAØGKT/7 --Steve
Reply to a comment by : W9PMZ on 2007-02-22

"antennas are NOT reciprocal in their transmit verses receive performance" Rewriting text books? Most antenna books that I have been privy to read starts the treatment of antennas by making a statement: "In this section we show that the radiation pattern of an antenna is the same whether it is used as a transmitting antenna or a receiving antenna. Reciprocity allows the calculation or measurement of an antenna pattern in either the transmit or receive case." (from Antenna Theory and Design by Stutzman and Thiele, page 40) Propagation at HF makes the antennas properties (height, length, etc) the issue, but the antenna still obeys reciprocity. 73, Carl - W9PMZ
Reply to a comment by : ONAIR on 2007-02-22

Interesting point. So a resonant vertical dipole would then be a lot more efficient than a vertical that you would need to tune?
N3OX2007-02-22
RE: Benchmarks
"When a dipole antenna is resonant, the ends become electrically open, thus allowing the antenna to transfer the most energy."

What are you talking about? The ends of the antenna are ALWAYS electrically open. They are not connected to anything.

"it is now out of resonance, and the ends become electrically shorted, thus producing standing waves or reflected power back thru the system. Where does this non-radiated power go, you ask? Up in heat, which is a completely different spectrum."

Reflections are caused by the antenna ends becoming short circuits? To what? The earth? Each other?

It is true that you get reflected power on the transmission line, unless, of course, you put a matching network right at the antenna like I like to do. There is a small loss in the matching network. Most people don't like to do that but the ones who are paying attention use ladderline at least.

- - - - - -

I'm not sure where you're coming from on a lot of this stuff.

Dan
Reply to a comment by : W4LGH on 2007-02-22

AA4PB wrote..."Alan, yes I am an Extra since 1995. My first class radiotelephone, ship radar endorsement and all amateur exams except the Extra were taken in front of an FCC examiner. Since 1963 I've made my living in electronics so I might have just a little experience. I submit that you are absolutely wrong in your assertion that a resonant antenna element length radiates more of the applied signal than a non-resonant length. A non-resonant length will radiate all of the power applied to it (less any losses) just as well as a resonant length. If this is not so then please explain where the power that is applied to the element but not radiated goes. If, instead of attacking people's intelligence, you will take the time to review the text books I believe you'll find that what many people here are telling you is indeed true." ========= Well then we have many things in common, including the same licenses and all of mine were taken in front of an FCC rep, and that I too have been professionally involved in electronics since 1963. I have a sneaky feeling that this discussion is going the same way as a previous thread on here where everyone was using CW as Morse Code, when in fact CW is an un-modulated carrier and MOrse code was the intellengence on the CW. Because of so many years of people using CW as meaning using Morse code, that no one understood the difference. When a dipole antenna is resonant, the ends become electrically open, thus allowing the antenna to transfer the most energy. IE: a dipole cut for 7100khz, will operate at it most efficency when a freq of 7100khz is applied to it. Now if you apply a freq of 7500Khz on this same antenna, it is now out of resonance, and the ends become electrically shorted, thus producing standing waves or reflected power back thru the system. Where does this non-radiated power go, you ask? Up in heat, which is a completely different spectrum. Now if you want to include this radiation along with the main signal radiation, then you can say a non-resonate antenna will radiate all its energy. However when I say a resonate antenna is more effecient, I am saying it is radiating the MOST USEABLE RF energy from the main source. The differences may be very minor, but measurable non the less. If you go by what everyone else is saying here, one could put up any random length dipole and use it for all bands 160m thur 1200 mhz., and one could, but at what loss or effeciency? To simple say a non-resoante antenna will radiate as much energy as a resonate one simple goes against the laws of physics, and we'd all have one antenna for all frequencies. There simply are no MAGIC BLACK BOX one antenna works all frequencies! Either I am missing something here or a lot of other are missing something, maybe a failure to communicate or lost in the translations. 73 de W4LGH - ALan http://www.w4lgh.com
Reply to a comment by : KA0GKT on 2007-02-22

Carl - W9PMZ wrote: "antennas are NOT reciprocal in their transmit verses receive performance" Rewriting text books? Most antenna books that I have been privy to read starts the treatment of antennas by making a statement: "In this section we show that the radiation pattern of an antenna is the same whether it is used as a transmitting antenna or a receiving antenna. Reciprocity allows the calculation or measurement of an antenna pattern in either the transmit or receive case." (from Antenna Theory and Design by Stutzman and Thiele, page 40) Propagation at HF makes the antennas properties (height, length, etc) the issue, but the antenna still obeys reciprocity. Antennas do indeed behave differently on receive than on transmit. The phenominon is called the Dipole factor and it has been documented since the time when the current NTSC TV channels were being laid out in the late 1940s. Since this was calculated for TV, the benchmark for the dipole factor is in the range of 47 MHz which was the original channel One. As the operating frequency increases, for a fixed signal density, the voltage at the terminals of a properly terminated dipole will decrease. For instance, with a 1 micro-volt/meter field strength, the voltage at the terminals of a dipole cut to 30 MHz will be 1.59 micro-volts. At a dipole cut for 50 MHz it will be .955 micro-volts; a 144 MHz dipole will have .332 micro-volts; a 220 MHz dipole will have .215 micro-volts; at 432 there will be .11 micro-volts. The formula to calculate dipole factor is: Et = Ef x ((300/F)/(2 x Pi)) Where: Et = RF voltage across the properly terminated terminals of the dipole. Ef = Field Strength in Volts per Meter F = Frequency in MHz Pi = 3.142 So, you can see that in order for a 70 cm antenna to provide the same level of reception as a 6 m dipole, the 70 cm antenna must have a 9.35 dBd gain. It must be noted that the dipole factor is only a factor for reception, when transmitting, a dipole is a dipole is a dipole. 73 DE KAØGKT/7 --Steve
Reply to a comment by : W9PMZ on 2007-02-22

"antennas are NOT reciprocal in their transmit verses receive performance" Rewriting text books? Most antenna books that I have been privy to read starts the treatment of antennas by making a statement: "In this section we show that the radiation pattern of an antenna is the same whether it is used as a transmitting antenna or a receiving antenna. Reciprocity allows the calculation or measurement of an antenna pattern in either the transmit or receive case." (from Antenna Theory and Design by Stutzman and Thiele, page 40) Propagation at HF makes the antennas properties (height, length, etc) the issue, but the antenna still obeys reciprocity. 73, Carl - W9PMZ
Reply to a comment by : ONAIR on 2007-02-22

Interesting point. So a resonant vertical dipole would then be a lot more efficient than a vertical that you would need to tune?
W4LGH2007-02-22
RE: Benchmarks
AA4PB wrote..."Alan, yes I am an Extra since 1995. My first class radiotelephone, ship radar endorsement and all amateur exams except the Extra were taken in front of an FCC examiner. Since 1963 I've made my living in electronics so I might have just a little experience. I submit that you are absolutely wrong in your assertion that a resonant antenna element length radiates more of the applied signal than a non-resonant length. A non-resonant length will radiate all of the power applied to it (less any losses) just as well as a resonant length. If this is not so then please explain where the power that is applied to the element but not radiated goes. If, instead of attacking people's intelligence, you will take the time to review the text books I believe you'll find that what many people here are telling you is indeed true."
=========
Well then we have many things in common, including the same licenses and all of mine were taken in front of an FCC rep, and that I too have been professionally involved in electronics since 1963.
I have a sneaky feeling that this discussion is going the same way as a previous thread on here where everyone was using CW as Morse Code, when in fact CW is an un-modulated carrier and MOrse code was the intellengence on the CW. Because of so many years of people using CW as meaning using Morse code, that no one understood the difference.

When a dipole antenna is resonant, the ends become electrically open, thus allowing the antenna to transfer the most energy. IE: a dipole cut for 7100khz, will operate at it most efficency when a freq of 7100khz is applied to it. Now if you apply a freq of 7500Khz on this same antenna, it is now out of resonance, and the ends become electrically shorted, thus producing standing waves or reflected power back thru the system. Where does this non-radiated power go, you ask? Up in heat, which is a completely different spectrum. Now if you want to include this radiation along with the main signal radiation, then you can say a non-resonate antenna will radiate all its energy. However when I say a resonate antenna is more effecient, I am saying it is radiating the MOST USEABLE RF energy from the main source. The differences may be very minor, but measurable non the less. If you go by what everyone else is saying here, one could put up any random length dipole and use it for all bands 160m thur 1200 mhz., and one could, but at what loss or effeciency?
To simple say a non-resoante antenna will radiate as much energy as a resonate one simple goes against the laws of physics, and we'd all have one antenna for all frequencies. There simply are no MAGIC BLACK BOX one antenna works all frequencies! Either I am missing something here or a lot of other are missing something, maybe a failure to communicate or lost in the translations.

73 de W4LGH - ALan
http://www.w4lgh.com


Reply to a comment by : KA0GKT on 2007-02-22

Carl - W9PMZ wrote: "antennas are NOT reciprocal in their transmit verses receive performance" Rewriting text books? Most antenna books that I have been privy to read starts the treatment of antennas by making a statement: "In this section we show that the radiation pattern of an antenna is the same whether it is used as a transmitting antenna or a receiving antenna. Reciprocity allows the calculation or measurement of an antenna pattern in either the transmit or receive case." (from Antenna Theory and Design by Stutzman and Thiele, page 40) Propagation at HF makes the antennas properties (height, length, etc) the issue, but the antenna still obeys reciprocity. Antennas do indeed behave differently on receive than on transmit. The phenominon is called the Dipole factor and it has been documented since the time when the current NTSC TV channels were being laid out in the late 1940s. Since this was calculated for TV, the benchmark for the dipole factor is in the range of 47 MHz which was the original channel One. As the operating frequency increases, for a fixed signal density, the voltage at the terminals of a properly terminated dipole will decrease. For instance, with a 1 micro-volt/meter field strength, the voltage at the terminals of a dipole cut to 30 MHz will be 1.59 micro-volts. At a dipole cut for 50 MHz it will be .955 micro-volts; a 144 MHz dipole will have .332 micro-volts; a 220 MHz dipole will have .215 micro-volts; at 432 there will be .11 micro-volts. The formula to calculate dipole factor is: Et = Ef x ((300/F)/(2 x Pi)) Where: Et = RF voltage across the properly terminated terminals of the dipole. Ef = Field Strength in Volts per Meter F = Frequency in MHz Pi = 3.142 So, you can see that in order for a 70 cm antenna to provide the same level of reception as a 6 m dipole, the 70 cm antenna must have a 9.35 dBd gain. It must be noted that the dipole factor is only a factor for reception, when transmitting, a dipole is a dipole is a dipole. 73 DE KAØGKT/7 --Steve
Reply to a comment by : W9PMZ on 2007-02-22

"antennas are NOT reciprocal in their transmit verses receive performance" Rewriting text books? Most antenna books that I have been privy to read starts the treatment of antennas by making a statement: "In this section we show that the radiation pattern of an antenna is the same whether it is used as a transmitting antenna or a receiving antenna. Reciprocity allows the calculation or measurement of an antenna pattern in either the transmit or receive case." (from Antenna Theory and Design by Stutzman and Thiele, page 40) Propagation at HF makes the antennas properties (height, length, etc) the issue, but the antenna still obeys reciprocity. 73, Carl - W9PMZ
Reply to a comment by : ONAIR on 2007-02-22

Interesting point. So a resonant vertical dipole would then be a lot more efficient than a vertical that you would need to tune?
KA0GKT2007-02-22
RE: Benchmarks
Carl - W9PMZ wrote:

"antennas are NOT reciprocal in their transmit verses receive performance"

Rewriting text books?

Most antenna books that I have been privy to read starts the treatment of antennas by making a statement:

"In this section we show that the radiation pattern of an antenna is the same whether it is used as a transmitting antenna or a receiving antenna. Reciprocity allows the calculation or measurement of an antenna pattern in either the transmit or receive case." (from Antenna Theory and Design by Stutzman and Thiele, page 40)

Propagation at HF makes the antennas properties (height, length, etc) the issue, but the antenna still obeys reciprocity.


Antennas do indeed behave differently on receive than on transmit. The phenominon is called the Dipole factor and it has been documented since the time when the current NTSC TV channels were being laid out in the late 1940s. Since this was calculated for TV, the benchmark for the dipole factor is in the range of 47 MHz which was the original channel One.

As the operating frequency increases, for a fixed signal density, the voltage at the terminals of a properly terminated dipole will decrease.

For instance, with a 1 micro-volt/meter field strength, the voltage at the terminals of a dipole cut to 30 MHz will be 1.59 micro-volts. At a dipole cut for 50 MHz it will be .955 micro-volts; a 144 MHz dipole will have .332 micro-volts; a 220 MHz dipole will have .215 micro-volts; at 432 there will be .11 micro-volts.

The formula to calculate dipole factor is:

Et = Ef x ((300/F)/(2 x Pi))

Where:
Et = RF voltage across the properly terminated terminals of the dipole.
Ef = Field Strength in Volts per Meter
F = Frequency in MHz
Pi = 3.142

So, you can see that in order for a 70 cm antenna to provide the same level of reception as a 6 m dipole, the 70 cm antenna must have a 9.35 dBd gain.

It must be noted that the dipole factor is only a factor for reception, when transmitting, a dipole is a dipole is a dipole.


73 DE KAØGKT/7

--Steve



Reply to a comment by : W9PMZ on 2007-02-22

"antennas are NOT reciprocal in their transmit verses receive performance" Rewriting text books? Most antenna books that I have been privy to read starts the treatment of antennas by making a statement: "In this section we show that the radiation pattern of an antenna is the same whether it is used as a transmitting antenna or a receiving antenna. Reciprocity allows the calculation or measurement of an antenna pattern in either the transmit or receive case." (from Antenna Theory and Design by Stutzman and Thiele, page 40) Propagation at HF makes the antennas properties (height, length, etc) the issue, but the antenna still obeys reciprocity. 73, Carl - W9PMZ
Reply to a comment by : ONAIR on 2007-02-22

Interesting point. So a resonant vertical dipole would then be a lot more efficient than a vertical that you would need to tune?
N3OX2007-02-22
RE: Benchmarks
"By the way, 3dB is a huge amount of difference when a signal is near noise floor. It is measningless when a signal is far above noise floor."

Yep. If you're a DXer, the S-unit is half full... if you're a ragchewer, the S-unit is half empty... or... something...

There's been many a DX station that I wished were an extra 3dB out of the noise. K7C on 40m while I was living in an apartment with a 30 foot high magnet wire doublet comes particularly to mind right now.

Dan
Reply to a comment by : N3OX on 2007-02-22

"If you want your antenna to radiate the RF, make sure it is as close a proper load to your transmitter as possible, to minimise loss." Sigh. This is true for antennas fed with moderate to long runs of coaxial cable. Let's leave it at that. Giving up for now. I'll be back later with more on this topic, I think. Dan
Reply to a comment by : KC8QFP on 2007-02-22

One simple thing I was taught about antennaes is sort of the golden rule, electricity seeks the lowest path of resistance. If you want your antenna to radiate the RF, make sure it is as close a proper load to your transmitter as possible, to minimise loss.
Reply to a comment by : K9IUQ on 2007-02-22

Antenna Discussions like this always show me how little Hams know about antennas. The same un-truths I hear on the air show up in print. If hams would only READ the antenna literature available the untruths would not persist.Some out right lies: Non-resonant antennas dont work as well as reasonant antennas. - - - How well an antenna performs has NOTHING to do with resonancy. A SWR of 3:1 is going to lose 25% of your power. - This guy needs to read the well respected book "Reflections" by Walter Maxell. On page 1-5 there is a wonderful chart that all hams should have on their wall. It shows loss in db according to SWR. This chart and excerpts from the book was recently reprinted in QST. Maxwell CLEARLY states a SWR (with good coax) as high as 5:1 will have an imperceptible difference on the receiving end vs a 1:1 swr. After 46 years of listening to and reading online about Antennas, I have concluded that most Hams know Little Antenna theory. It aint Voo-doo or magic fellows, antenna perfomance and theory has been well established. we only have to get our information from respected books - NOT other Hams or eham discussions. K9IUQ
N3OX2007-02-22
RE: Benchmarks
"If you want your antenna to radiate the RF, make sure it is as close a proper load to your transmitter as possible, to minimise loss."

Sigh.

This is true for antennas fed with moderate to long runs of coaxial cable. Let's leave it at that.

Giving up for now. I'll be back later with more on this topic, I think.

Dan
Reply to a comment by : KC8QFP on 2007-02-22

One simple thing I was taught about antennaes is sort of the golden rule, electricity seeks the lowest path of resistance. If you want your antenna to radiate the RF, make sure it is as close a proper load to your transmitter as possible, to minimise loss.
Reply to a comment by : K9IUQ on 2007-02-22

Antenna Discussions like this always show me how little Hams know about antennas. The same un-truths I hear on the air show up in print. If hams would only READ the antenna literature available the untruths would not persist.Some out right lies: Non-resonant antennas dont work as well as reasonant antennas. - - - How well an antenna performs has NOTHING to do with resonancy. A SWR of 3:1 is going to lose 25% of your power. - This guy needs to read the well respected book "Reflections" by Walter Maxell. On page 1-5 there is a wonderful chart that all hams should have on their wall. It shows loss in db according to SWR. This chart and excerpts from the book was recently reprinted in QST. Maxwell CLEARLY states a SWR (with good coax) as high as 5:1 will have an imperceptible difference on the receiving end vs a 1:1 swr. After 46 years of listening to and reading online about Antennas, I have concluded that most Hams know Little Antenna theory. It aint Voo-doo or magic fellows, antenna perfomance and theory has been well established. we only have to get our information from respected books - NOT other Hams or eham discussions. K9IUQ
W8JI2007-02-22
RE: No Myth
90% of power can be lost in a tuner, but truthfully it is tough to have even 20-30% loss. If you ran 500 watts and just 10% of the power was lost in a tuner, the tuner would likely smoke and melt on CW.

Heat is heat. 50 watts lost in the tuner would be like placing a 50W lightbulb in the tuner case. Anyone running more than a few hundred watts would KNOW if the tuner had high loss becuase of the smoke. The exception is feedlines; where loss is distributed over a large area. The large area can let heat out.

Alan NEVER said anything about reciprocity. What he did say was antenna do not have the same performance.

Reciprocity means an antenna has the same pattern aand gain when transmitting and receiving. When receiving (if the sinal from the antenna establishes noise floor) only directivity and response to the direction and polarization of signals and noise affects S/N ratio. NOT gain. (When transmitting, only gain in the desired direction matters.)

I have a feedline loss of 5dB on 160-10 meters, a typical reasonable size antenna, and I change the feedline and now have 1 dB loss. S/N ratio and abilitly to hear weak signals won't change a bit. The only exception would be if the receiver noise floor was so high or the antenna so tiny that the noise temperature of the feedline set the noise floor. The transmitting improved 4dB everywhere, but I won't hear the least amount better.

Anyone claiming a 5dB gain antenna gives the same 5dB better S/N when receiving is probably wrong. The actual change can be anything from dozens of dB to a loss in S/N on receive.

While the antenna pattern is the same and the gain the same, the S/N improvement is almost never the same.

By the way, a system with loss is not necessarily bilaterial. A feedline can have different loss when receiving, as can a tuner. This is because impedances are not always bilaterial (the same in each direction) in a lossy system.

Feedline loss isn't necessarily the same on RX and TX. The receiver sets system SWR when receiving, the antenna sets SWR when transmitting. A tuner in the system often won't have the same loss or impedance ratio with different signal directions.

It's also true that a resonant antenna is not necessarily more efficient than an antenna with reactance.

By the way, 3dB is a huge amount of difference when a signal is near noise floor. It is measningless when a signal is far above noise floor. Even 1/2 dB can be a huge difference in readability when a signal is right at noise floor. All that said, it makes no sense to worry about 1/2 dB if it compromises the quality of the signal.

Some idiots actually get inside radios and turn power controls up, making a 100 watt radio run 125 or even 150 watts. What a stupid thing to do. The radio deteriorates 10-15dB for IM performance (splatter) while the user picks up a fraction of a dB on frequency, and the change seriously shortens the life of PA transistors.

73 Tom





Reply to a comment by : N4SL on 2007-02-22

I can transmit 1500W output continuous duty for 10 minutes, then power down and FEEL THE TRANSMATCH COMPONENTS. My balun is a little warm, the rest is at room temp. Loss? Oh, about 10W. What's that, 0.3dB? OOooooooh, huge losses, watch out! Don't believe me? Good, I'll keep kicking your asses in the contests until you go back and read the books from the 30's and 40's when all hams used real open wire balanced transmission lines with near-zero loss at HF. I do enjoy the concept that an antenna must be resonant to couple to the ether, that's funny.
Reply to a comment by : W4LGH on 2007-02-22

W6TH Vito wrote.. ~"W4LGH Alan, I've heard enough of your bullshit, enough is enough."~ Well Mr Vito...That certainly was an educated response! I have seen it all in my career, from a 5 gallon bucket of dirt in a guys trunk, because the instructions said "This wire needs to go to EARTH ground", to a station engineer who wouldn't let anyone install any antennas upside down on his tower because he said, RF would leak out. I guess some people take things to litteral, and some don't take it litteral enough. A lot of good info in this thread, but again it goes to show you can not POST a good article here on eHam, no matter what, people will try to tear it apart. No one understands friendly debate. 73 de W4LGH - Alan
Reply to a comment by : W6TH on 2007-02-22

. W4LGH Alan, I've heard enough of your bullshit, enough is enough. W6TH .:
Reply to a comment by : W6TH on 2007-02-22

. Frequency = 1 divided by time. Time is relevant. Known as the Black Hole. No Myth. .:
Reply to a comment by : N3OX on 2007-02-22

"But the tuner was at the antenna feed point, matching the antenna impedance to the radio, it worked, and I certainly didn't have extra power to spare, but it would have worked BETTER, had the wire been resonant on the frequency I was using" Untrue.
Reply to a comment by : N3OX on 2007-02-22

W4LGH: The excerpt you quoted from that page explains that a center fed antenna has the lowest possible impedance when it's half-wave resonant (or three-halves or five halves, whatever); that is, if you fix the ***voltage*** you feed to an antenna, you'll get the most current, and therefore the biggest field, when it's an odd multiple of a half wave. If you force the same current in a similar, but nonresonant antenna, you get the same strength field (up to the antenna being a little bit shorter or longer which affects its gain in a minor fashion). If you had a magical transistor or tube that didn't care if the voltage was not in phase with the current and didn't care how high that voltage got, you would never have to match to a nonresonant antenna. We always say that we're "transforming the antenna impedance" with a network, but we could equally say "we're transforming the transmitter output up to a voltage with the proper phase to drive the a particular current into the antenna impedance" An article I found that's more precise: http://www.cv.nrao.edu/course/astr534/AntennaTheory.html There's a bunch of stuff later on that isn't particularly applicable to our current discussion, like the impedance of a black hole, but they do talk about reciprocity later on in the page. 73, Dan
Reply to a comment by : W6TH on 2007-02-22

. W4LGH We have been talking about transmitting antennas, I would like to know a specific purpose for using a non-resonant antenna on a transmitter. ..................................................... A long-wire antenna radiates more power in its most favorable direction than does a half wave resonant antenna in its most favorable direction. This power gain is secured at the expense of radiation in other directions. Would you like me to run some analytical Geometry for you? Maybe my math can convince you. Better yet, lets see what your math can do for me. 73, W6TH .:
Reply to a comment by : W4LGH on 2007-02-22

W6TH wrote..."This is no myth, but the truth. A resonant antenna and a non resonant antenna are both efficient antennas; non are better than the other, each has its own purpose for use." We have been talking about transmitting antennas, I would like to know a specific purpose for using a non-resonant antenna on a transmitter. If one truely understands resonance, I don't understand how anything can be as efficient as one that is resonant. And it is proven to you everytime you load up a transmitter. I certainly understand that weird things will work, but that doesn't make it so. I worked over 15 countries running 3 watts or less into a 50' wire fed at the end with an MFJ 16010 tuner. But the tuner was at the antenna feed point, matching the antenna impedance to the radio, it worked, and I certainly didn't have extra power to spare, but it would have worked BETTER, had the wire been resonant on the frequency I was using, certainly more efficient, as at resonancde the end of the wire looks like an open circuit, where as off resonance it begins to look like a short. 73 de W4LGH Alan http://www.w4lgh.com
Reply to a comment by : W6TH on 2007-02-22

. This is no myth, but the truth. A resonant antenna and a non resonant antenna are both efficient antennas; non are better than the other, each has its own purpose for use. W6TH .:
Reply to a comment by : WB2WIK on 2007-02-22

Not all solid state rigs reduce output power beginning at VSWR = 1.5. That is ultra conservative. The Ten Tec transceivers for years used a circuit breaker in the power supply to tell the transceiver when to "cut back power" due to high VSWR. They'd shut off! But until the breaker tripped, they'd keep transmitting. My Drake TR-7, by published specification, provides 90% of its full rated output power into a 2:1 VSWR and doesn't "fold back" to 50% (which is still about 75W output power) until VSWR = 5:1. That detail is listed here on the last page of the TR-7 brochure: http://wb4hfn.com/DRAKE/DrakeCatalogsBrochures/Brochure_TR7_04B.htm As such, the TR-7 hardly needs a tuner unless the user intends some pretty serious mismatches. Mine can easily produce 100W output power into a 3:1 mismatch, on any band. Without a tuner. It's largely a matter of "headroom" for the power amplifying devices selected. Margins include current, voltage and heat. One problem with a little rig like the FT-857 is its PA devices are small and its PA heatsink is *very* small, not capable of carrying much heat away from the devices, even with a fan. The TR-7 power amplifier heatsink alone (just the heatsink) is larger than the entire FT-857... WB2WIK/6
Reply to a comment by : K6HWH on 2007-02-22

"Every solidstate radio I have ever owned started shutting down power at a 1.5 swr." What about this? I have a Yaesu 857 that does indeed crank down transmit power if the SWR is the least bit off, ostensibly to prevent damage to the output transistors. If even a SWR of 5 does not diminish appreciable the antenna's ability to radiate, isn't this a mistake? Should I be looking for a way to defeat the 857's cautious approach to SWR?
Reply to a comment by : K3AN on 2007-02-22

This article is evidence that you can't determine the usefulness or accuracy of an article by the number of words. If you want useful, accurate information on antennas, please visit the L.B. Cebik web site www.cebik.com. For the last time, there is nothing magical about resonant antennas.
Reply to a comment by : N3OX on 2007-02-22

Respectfully, W4LGH, I would like to point out that you are the one muddying the waters about a *resonant antenna* and its radiating effectiveness. It is not true that antenna element resonance has anything to do with coupling power into the electromagnetic field around the antenna. The *REAL* part of the antenna impedance has two components, the radiation resistance and the loss resistance. That fraction of the power which is associated with "dissipation" in the radiation resistance is the power that gets radiated. The fraction associated with dissipation in the loss resistance goes up as heat. The power in the reactive part of the impedance is simply stored in fields around the antenna. That means that an antenna with an impedance of 70+j0 and one with an impedance of 70+j500 are radiating exactly the same amount of power if you can feed that power to them in the first place. You need to match the antenna system to the transmitter but resonance of the antenna element itself has nothing at all to do with the transfer of that power to radiating electromagnetic fields. If you are supplying 100W to the antenna, 100W minus the antenna losses is radiated, no matter whether or not the antenna element is resonant. 73, Dan
Reply to a comment by : W4LGH on 2007-02-22

You see, here we go again, a good article is written, it contains some great info. Some additional articles are written taken it a little further. Then come the people who truely do not understand what is being said, and either go on what they have seen, or what somebody else who truely doesn't understand told them. ==================================================== Now... AA4PB writes..."at resonance the antenna is inducing more power into the atmosphere ---------------------------------------------------- Can you point us to a definitive text that proves this, or even claims it to be true?" ==================================================== Now with a call like this, this guy is at least an "ADVANCED" class if not an "EXTRA" class, what I said is basic "Physics 101" Resonance is a common thread which runs through almost every branch of physics, and yet a lot of people have never studied it. Without resonance we wouldn't have radio, television, music, or swings on playgrounds, not to mention cool gismos like Tesla coils. Of course, resonance also has its dark side. It occasionally causes a bridge to collapse, a helicopter to fly apart, or other inconveniences. Unlike black holes, time travel, and quantum mechanics, resonance is common place and easy to observe. Yet, it is one of the most striking and unexpected phenomenon in all of physics. It is relative to everything. Here is a good link to read about it...hopefully it will explain.. http://www.intuitor.com/resonance/circuits.html Ever heard the term, "Dip the Plate" when tuning? Notice how the plate current drops but your output increases? Wonder why that is? Could it be your tank circuit has been tuned to resonance? Hmmm...your antenna is an extension of your tank circuit. And to K9IUQ...who wrote..."Also resonance of the SYSTEM has nothing to do with how well the antenna radiates. This is determined by MANY other factors. I have a wonderful Dummy load antenna under my desk that is resonant on all HF bands, however it doesnt seem to radiate very well since I haven't worked too many people with it."... I give up here, this guy just isn't with the program...A dummy LOAD is NOT resonate, it is a resistive LOAD designed to burn up the power by turning it into HEAT! Thats why they call it a dummy LOAD! (key word there is LOAD) Man..you guys say you want elmers, if you truely do not understand something, thats ok, there are people who do understand, and more than willing to help. 73 de W4LGH Alan http://www.w4lgh.com
Reply to a comment by : AA4PB on 2007-02-22

at resonance the antenna is inducing more power into the atmosphere ---------------------------------------------------- Can you point us to a definitive text that proves this, or even claims it to be true?
Reply to a comment by : K9IUQ on 2007-02-22

One TRUE statement was made, a RESONATE antenna will work BETTER than a NON_RESONATE antenna. People do NOT understand resonance ..................................................... The above is an false statement. An Antenna is resonant at ONLY ONE frequency. At any other frequency it is non-resonant. We all use non-resonant antennas (including you) on a daily basis. We make the antenna SYSTEM resonant with a tuner of one kind or another or live with SWR higher than 1:1. Agreed - the whole SYSTEM must be resonance -from the radio to the antenna. It makes little difference if the antenna itself is resonance or not.Many of the best performing wire antennas are non-resonant fed with open wire feeders and an antenna tuner. Also resonance of the SYSTEM has nothing to do with how well the antenna radiates. This is determined by MANY other factors. I have a wonderful Dummy load antenna under my desk that is resonant on all HF bands, however it doesnt seem to radiate very well since I haven't worked too many people with it. Please Pick Up an antenna Book like "Reflections" and learn the facts instead of trying to sell me 'some wonderful ocean front property in Arizona " K9IUQ
KC8QFP2007-02-22
RE: Benchmarks
One simple thing I was taught about antennaes is sort of the golden rule, electricity seeks the lowest path of resistance. If you want your antenna to radiate the RF, make sure it is as close a proper load to your transmitter as possible, to minimise loss.
Reply to a comment by : K9IUQ on 2007-02-22

Antenna Discussions like this always show me how little Hams know about antennas. The same un-truths I hear on the air show up in print. If hams would only READ the antenna literature available the untruths would not persist.Some out right lies: Non-resonant antennas dont work as well as reasonant antennas. - - - How well an antenna performs has NOTHING to do with resonancy. A SWR of 3:1 is going to lose 25% of your power. - This guy needs to read the well respected book "Reflections" by Walter Maxell. On page 1-5 there is a wonderful chart that all hams should have on their wall. It shows loss in db according to SWR. This chart and excerpts from the book was recently reprinted in QST. Maxwell CLEARLY states a SWR (with good coax) as high as 5:1 will have an imperceptible difference on the receiving end vs a 1:1 swr. After 46 years of listening to and reading online about Antennas, I have concluded that most Hams know Little Antenna theory. It aint Voo-doo or magic fellows, antenna perfomance and theory has been well established. we only have to get our information from respected books - NOT other Hams or eham discussions. K9IUQ
AA4PB2007-02-22
RE: No Myth
Alan, yes I am an Extra since 1995. My first class radiotelephone, ship radar endorsement and all amateur exams except the Extra were taken in front of an FCC examiner.

Since 1963 I've made my living in electronics so I might have just a little experience.

I submit that you are absolutely wrong in your assertion that a resonant antenna element length radiates more of the applied signal than a non-resonant length. A non-resonant length will radiate all of the power applied to it (less any losses) just as well as a resonant length. If this is not so then please explain where the power that is applied to the element but not radiated goes. If, instead of attacking people's intelligence, you will take the time to review the text books I believe you'll find that what many people here are telling you is indeed true.
Reply to a comment by : W4LGH on 2007-02-22

W6TH Vito wrote.. ~"W4LGH Alan, I've heard enough of your bullshit, enough is enough."~ Well Mr Vito...That certainly was an educated response! I have seen it all in my career, from a 5 gallon bucket of dirt in a guys trunk, because the instructions said "This wire needs to go to EARTH ground", to a station engineer who wouldn't let anyone install any antennas upside down on his tower because he said, RF would leak out. I guess some people take things to litteral, and some don't take it litteral enough. A lot of good info in this thread, but again it goes to show you can not POST a good article here on eHam, no matter what, people will try to tear it apart. No one understands friendly debate. 73 de W4LGH - Alan
Reply to a comment by : W6TH on 2007-02-22

. W4LGH Alan, I've heard enough of your bullshit, enough is enough. W6TH .:
Reply to a comment by : W6TH on 2007-02-22

. Frequency = 1 divided by time. Time is relevant. Known as the Black Hole. No Myth. .:
Reply to a comment by : N3OX on 2007-02-22

"But the tuner was at the antenna feed point, matching the antenna impedance to the radio, it worked, and I certainly didn't have extra power to spare, but it would have worked BETTER, had the wire been resonant on the frequency I was using" Untrue.
Reply to a comment by : N3OX on 2007-02-22

W4LGH: The excerpt you quoted from that page explains that a center fed antenna has the lowest possible impedance when it's half-wave resonant (or three-halves or five halves, whatever); that is, if you fix the ***voltage*** you feed to an antenna, you'll get the most current, and therefore the biggest field, when it's an odd multiple of a half wave. If you force the same current in a similar, but nonresonant antenna, you get the same strength field (up to the antenna being a little bit shorter or longer which affects its gain in a minor fashion). If you had a magical transistor or tube that didn't care if the voltage was not in phase with the current and didn't care how high that voltage got, you would never have to match to a nonresonant antenna. We always say that we're "transforming the antenna impedance" with a network, but we could equally say "we're transforming the transmitter output up to a voltage with the proper phase to drive the a particular current into the antenna impedance" An article I found that's more precise: http://www.cv.nrao.edu/course/astr534/AntennaTheory.html There's a bunch of stuff later on that isn't particularly applicable to our current discussion, like the impedance of a black hole, but they do talk about reciprocity later on in the page. 73, Dan
Reply to a comment by : W6TH on 2007-02-22

. W4LGH We have been talking about transmitting antennas, I would like to know a specific purpose for using a non-resonant antenna on a transmitter. ..................................................... A long-wire antenna radiates more power in its most favorable direction than does a half wave resonant antenna in its most favorable direction. This power gain is secured at the expense of radiation in other directions. Would you like me to run some analytical Geometry for you? Maybe my math can convince you. Better yet, lets see what your math can do for me. 73, W6TH .:
Reply to a comment by : W4LGH on 2007-02-22

W6TH wrote..."This is no myth, but the truth. A resonant antenna and a non resonant antenna are both efficient antennas; non are better than the other, each has its own purpose for use." We have been talking about transmitting antennas, I would like to know a specific purpose for using a non-resonant antenna on a transmitter. If one truely understands resonance, I don't understand how anything can be as efficient as one that is resonant. And it is proven to you everytime you load up a transmitter. I certainly understand that weird things will work, but that doesn't make it so. I worked over 15 countries running 3 watts or less into a 50' wire fed at the end with an MFJ 16010 tuner. But the tuner was at the antenna feed point, matching the antenna impedance to the radio, it worked, and I certainly didn't have extra power to spare, but it would have worked BETTER, had the wire been resonant on the frequency I was using, certainly more efficient, as at resonancde the end of the wire looks like an open circuit, where as off resonance it begins to look like a short. 73 de W4LGH Alan http://www.w4lgh.com
Reply to a comment by : W6TH on 2007-02-22

. This is no myth, but the truth. A resonant antenna and a non resonant antenna are both efficient antennas; non are better than the other, each has its own purpose for use. W6TH .:
Reply to a comment by : WB2WIK on 2007-02-22

Not all solid state rigs reduce output power beginning at VSWR = 1.5. That is ultra conservative. The Ten Tec transceivers for years used a circuit breaker in the power supply to tell the transceiver when to "cut back power" due to high VSWR. They'd shut off! But until the breaker tripped, they'd keep transmitting. My Drake TR-7, by published specification, provides 90% of its full rated output power into a 2:1 VSWR and doesn't "fold back" to 50% (which is still about 75W output power) until VSWR = 5:1. That detail is listed here on the last page of the TR-7 brochure: http://wb4hfn.com/DRAKE/DrakeCatalogsBrochures/Brochure_TR7_04B.htm As such, the TR-7 hardly needs a tuner unless the user intends some pretty serious mismatches. Mine can easily produce 100W output power into a 3:1 mismatch, on any band. Without a tuner. It's largely a matter of "headroom" for the power amplifying devices selected. Margins include current, voltage and heat. One problem with a little rig like the FT-857 is its PA devices are small and its PA heatsink is *very* small, not capable of carrying much heat away from the devices, even with a fan. The TR-7 power amplifier heatsink alone (just the heatsink) is larger than the entire FT-857... WB2WIK/6
Reply to a comment by : K6HWH on 2007-02-22

"Every solidstate radio I have ever owned started shutting down power at a 1.5 swr." What about this? I have a Yaesu 857 that does indeed crank down transmit power if the SWR is the least bit off, ostensibly to prevent damage to the output transistors. If even a SWR of 5 does not diminish appreciable the antenna's ability to radiate, isn't this a mistake? Should I be looking for a way to defeat the 857's cautious approach to SWR?
Reply to a comment by : K3AN on 2007-02-22

This article is evidence that you can't determine the usefulness or accuracy of an article by the number of words. If you want useful, accurate information on antennas, please visit the L.B. Cebik web site www.cebik.com. For the last time, there is nothing magical about resonant antennas.
Reply to a comment by : N3OX on 2007-02-22

Respectfully, W4LGH, I would like to point out that you are the one muddying the waters about a *resonant antenna* and its radiating effectiveness. It is not true that antenna element resonance has anything to do with coupling power into the electromagnetic field around the antenna. The *REAL* part of the antenna impedance has two components, the radiation resistance and the loss resistance. That fraction of the power which is associated with "dissipation" in the radiation resistance is the power that gets radiated. The fraction associated with dissipation in the loss resistance goes up as heat. The power in the reactive part of the impedance is simply stored in fields around the antenna. That means that an antenna with an impedance of 70+j0 and one with an impedance of 70+j500 are radiating exactly the same amount of power if you can feed that power to them in the first place. You need to match the antenna system to the transmitter but resonance of the antenna element itself has nothing at all to do with the transfer of that power to radiating electromagnetic fields. If you are supplying 100W to the antenna, 100W minus the antenna losses is radiated, no matter whether or not the antenna element is resonant. 73, Dan
Reply to a comment by : W4LGH on 2007-02-22

You see, here we go again, a good article is written, it contains some great info. Some additional articles are written taken it a little further. Then come the people who truely do not understand what is being said, and either go on what they have seen, or what somebody else who truely doesn't understand told them. ==================================================== Now... AA4PB writes..."at resonance the antenna is inducing more power into the atmosphere ---------------------------------------------------- Can you point us to a definitive text that proves this, or even claims it to be true?" ==================================================== Now with a call like this, this guy is at least an "ADVANCED" class if not an "EXTRA" class, what I said is basic "Physics 101" Resonance is a common thread which runs through almost every branch of physics, and yet a lot of people have never studied it. Without resonance we wouldn't have radio, television, music, or swings on playgrounds, not to mention cool gismos like Tesla coils. Of course, resonance also has its dark side. It occasionally causes a bridge to collapse, a helicopter to fly apart, or other inconveniences. Unlike black holes, time travel, and quantum mechanics, resonance is common place and easy to observe. Yet, it is one of the most striking and unexpected phenomenon in all of physics. It is relative to everything. Here is a good link to read about it...hopefully it will explain.. http://www.intuitor.com/resonance/circuits.html Ever heard the term, "Dip the Plate" when tuning? Notice how the plate current drops but your output increases? Wonder why that is? Could it be your tank circuit has been tuned to resonance? Hmmm...your antenna is an extension of your tank circuit. And to K9IUQ...who wrote..."Also resonance of the SYSTEM has nothing to do with how well the antenna radiates. This is determined by MANY other factors. I have a wonderful Dummy load antenna under my desk that is resonant on all HF bands, however it doesnt seem to radiate very well since I haven't worked too many people with it."... I give up here, this guy just isn't with the program...A dummy LOAD is NOT resonate, it is a resistive LOAD designed to burn up the power by turning it into HEAT! Thats why they call it a dummy LOAD! (key word there is LOAD) Man..you guys say you want elmers, if you truely do not understand something, thats ok, there are people who do understand, and more than willing to help. 73 de W4LGH Alan http://www.w4lgh.com
Reply to a comment by : AA4PB on 2007-02-22

at resonance the antenna is inducing more power into the atmosphere ---------------------------------------------------- Can you point us to a definitive text that proves this, or even claims it to be true?
Reply to a comment by : K9IUQ on 2007-02-22

One TRUE statement was made, a RESONATE antenna will work BETTER than a NON_RESONATE antenna. People do NOT understand resonance ..................................................... The above is an false statement. An Antenna is resonant at ONLY ONE frequency. At any other frequency it is non-resonant. We all use non-resonant antennas (including you) on a daily basis. We make the antenna SYSTEM resonant with a tuner of one kind or another or live with SWR higher than 1:1. Agreed - the whole SYSTEM must be resonance -from the radio to the antenna. It makes little difference if the antenna itself is resonance or not.Many of the best performing wire antennas are non-resonant fed with open wire feeders and an antenna tuner. Also resonance of the SYSTEM has nothing to do with how well the antenna radiates. This is determined by MANY other factors. I have a wonderful Dummy load antenna under my desk that is resonant on all HF bands, however it doesnt seem to radiate very well since I haven't worked too many people with it. Please Pick Up an antenna Book like "Reflections" and learn the facts instead of trying to sell me 'some wonderful ocean front property in Arizona " K9IUQ
N4SL2007-02-22
RE: No Myth
I can transmit 1500W output continuous duty for 10 minutes, then power down and FEEL THE TRANSMATCH COMPONENTS. My balun is a little warm, the rest is at room temp. Loss? Oh, about 10W. What's that, 0.3dB?

OOooooooh, huge losses, watch out!

Don't believe me?

Good, I'll keep kicking your asses in the contests until you go back and read the books from the 30's and 40's when all hams used real open wire balanced transmission lines with near-zero loss at HF.

I do enjoy the concept that an antenna must be resonant to couple to the ether, that's funny.
Reply to a comment by : W4LGH on 2007-02-22

W6TH Vito wrote.. ~"W4LGH Alan, I've heard enough of your bullshit, enough is enough."~ Well Mr Vito...That certainly was an educated response! I have seen it all in my career, from a 5 gallon bucket of dirt in a guys trunk, because the instructions said "This wire needs to go to EARTH ground", to a station engineer who wouldn't let anyone install any antennas upside down on his tower because he said, RF would leak out. I guess some people take things to litteral, and some don't take it litteral enough. A lot of good info in this thread, but again it goes to show you can not POST a good article here on eHam, no matter what, people will try to tear it apart. No one understands friendly debate. 73 de W4LGH - Alan
Reply to a comment by : W6TH on 2007-02-22

. W4LGH Alan, I've heard enough of your bullshit, enough is enough. W6TH .:
Reply to a comment by : W6TH on 2007-02-22

. Frequency = 1 divided by time. Time is relevant. Known as the Black Hole. No Myth. .:
Reply to a comment by : N3OX on 2007-02-22

"But the tuner was at the antenna feed point, matching the antenna impedance to the radio, it worked, and I certainly didn't have extra power to spare, but it would have worked BETTER, had the wire been resonant on the frequency I was using" Untrue.
Reply to a comment by : N3OX on 2007-02-22

W4LGH: The excerpt you quoted from that page explains that a center fed antenna has the lowest possible impedance when it's half-wave resonant (or three-halves or five halves, whatever); that is, if you fix the ***voltage*** you feed to an antenna, you'll get the most current, and therefore the biggest field, when it's an odd multiple of a half wave. If you force the same current in a similar, but nonresonant antenna, you get the same strength field (up to the antenna being a little bit shorter or longer which affects its gain in a minor fashion). If you had a magical transistor or tube that didn't care if the voltage was not in phase with the current and didn't care how high that voltage got, you would never have to match to a nonresonant antenna. We always say that we're "transforming the antenna impedance" with a network, but we could equally say "we're transforming the transmitter output up to a voltage with the proper phase to drive the a particular current into the antenna impedance" An article I found that's more precise: http://www.cv.nrao.edu/course/astr534/AntennaTheory.html There's a bunch of stuff later on that isn't particularly applicable to our current discussion, like the impedance of a black hole, but they do talk about reciprocity later on in the page. 73, Dan
Reply to a comment by : W6TH on 2007-02-22

. W4LGH We have been talking about transmitting antennas, I would like to know a specific purpose for using a non-resonant antenna on a transmitter. ..................................................... A long-wire antenna radiates more power in its most favorable direction than does a half wave resonant antenna in its most favorable direction. This power gain is secured at the expense of radiation in other directions. Would you like me to run some analytical Geometry for you? Maybe my math can convince you. Better yet, lets see what your math can do for me. 73, W6TH .:
Reply to a comment by : W4LGH on 2007-02-22

W6TH wrote..."This is no myth, but the truth. A resonant antenna and a non resonant antenna are both efficient antennas; non are better than the other, each has its own purpose for use." We have been talking about transmitting antennas, I would like to know a specific purpose for using a non-resonant antenna on a transmitter. If one truely understands resonance, I don't understand how anything can be as efficient as one that is resonant. And it is proven to you everytime you load up a transmitter. I certainly understand that weird things will work, but that doesn't make it so. I worked over 15 countries running 3 watts or less into a 50' wire fed at the end with an MFJ 16010 tuner. But the tuner was at the antenna feed point, matching the antenna impedance to the radio, it worked, and I certainly didn't have extra power to spare, but it would have worked BETTER, had the wire been resonant on the frequency I was using, certainly more efficient, as at resonancde the end of the wire looks like an open circuit, where as off resonance it begins to look like a short. 73 de W4LGH Alan http://www.w4lgh.com
Reply to a comment by : W6TH on 2007-02-22

. This is no myth, but the truth. A resonant antenna and a non resonant antenna are both efficient antennas; non are better than the other, each has its own purpose for use. W6TH .:
Reply to a comment by : WB2WIK on 2007-02-22

Not all solid state rigs reduce output power beginning at VSWR = 1.5. That is ultra conservative. The Ten Tec transceivers for years used a circuit breaker in the power supply to tell the transceiver when to "cut back power" due to high VSWR. They'd shut off! But until the breaker tripped, they'd keep transmitting. My Drake TR-7, by published specification, provides 90% of its full rated output power into a 2:1 VSWR and doesn't "fold back" to 50% (which is still about 75W output power) until VSWR = 5:1. That detail is listed here on the last page of the TR-7 brochure: http://wb4hfn.com/DRAKE/DrakeCatalogsBrochures/Brochure_TR7_04B.htm As such, the TR-7 hardly needs a tuner unless the user intends some pretty serious mismatches. Mine can easily produce 100W output power into a 3:1 mismatch, on any band. Without a tuner. It's largely a matter of "headroom" for the power amplifying devices selected. Margins include current, voltage and heat. One problem with a little rig like the FT-857 is its PA devices are small and its PA heatsink is *very* small, not capable of carrying much heat away from the devices, even with a fan. The TR-7 power amplifier heatsink alone (just the heatsink) is larger than the entire FT-857... WB2WIK/6
Reply to a comment by : K6HWH on 2007-02-22

"Every solidstate radio I have ever owned started shutting down power at a 1.5 swr." What about this? I have a Yaesu 857 that does indeed crank down transmit power if the SWR is the least bit off, ostensibly to prevent damage to the output transistors. If even a SWR of 5 does not diminish appreciable the antenna's ability to radiate, isn't this a mistake? Should I be looking for a way to defeat the 857's cautious approach to SWR?
Reply to a comment by : K3AN on 2007-02-22

This article is evidence that you can't determine the usefulness or accuracy of an article by the number of words. If you want useful, accurate information on antennas, please visit the L.B. Cebik web site www.cebik.com. For the last time, there is nothing magical about resonant antennas.
Reply to a comment by : N3OX on 2007-02-22

Respectfully, W4LGH, I would like to point out that you are the one muddying the waters about a *resonant antenna* and its radiating effectiveness. It is not true that antenna element resonance has anything to do with coupling power into the electromagnetic field around the antenna. The *REAL* part of the antenna impedance has two components, the radiation resistance and the loss resistance. That fraction of the power which is associated with "dissipation" in the radiation resistance is the power that gets radiated. The fraction associated with dissipation in the loss resistance goes up as heat. The power in the reactive part of the impedance is simply stored in fields around the antenna. That means that an antenna with an impedance of 70+j0 and one with an impedance of 70+j500 are radiating exactly the same amount of power if you can feed that power to them in the first place. You need to match the antenna system to the transmitter but resonance of the antenna element itself has nothing at all to do with the transfer of that power to radiating electromagnetic fields. If you are supplying 100W to the antenna, 100W minus the antenna losses is radiated, no matter whether or not the antenna element is resonant. 73, Dan
Reply to a comment by : W4LGH on 2007-02-22

You see, here we go again, a good article is written, it contains some great info. Some additional articles are written taken it a little further. Then come the people who truely do not understand what is being said, and either go on what they have seen, or what somebody else who truely doesn't understand told them. ==================================================== Now... AA4PB writes..."at resonance the antenna is inducing more power into the atmosphere ---------------------------------------------------- Can you point us to a definitive text that proves this, or even claims it to be true?" ==================================================== Now with a call like this, this guy is at least an "ADVANCED" class if not an "EXTRA" class, what I said is basic "Physics 101" Resonance is a common thread which runs through almost every branch of physics, and yet a lot of people have never studied it. Without resonance we wouldn't have radio, television, music, or swings on playgrounds, not to mention cool gismos like Tesla coils. Of course, resonance also has its dark side. It occasionally causes a bridge to collapse, a helicopter to fly apart, or other inconveniences. Unlike black holes, time travel, and quantum mechanics, resonance is common place and easy to observe. Yet, it is one of the most striking and unexpected phenomenon in all of physics. It is relative to everything. Here is a good link to read about it...hopefully it will explain.. http://www.intuitor.com/resonance/circuits.html Ever heard the term, "Dip the Plate" when tuning? Notice how the plate current drops but your output increases? Wonder why that is? Could it be your tank circuit has been tuned to resonance? Hmmm...your antenna is an extension of your tank circuit. And to K9IUQ...who wrote..."Also resonance of the SYSTEM has nothing to do with how well the antenna radiates. This is determined by MANY other factors. I have a wonderful Dummy load antenna under my desk that is resonant on all HF bands, however it doesnt seem to radiate very well since I haven't worked too many people with it."... I give up here, this guy just isn't with the program...A dummy LOAD is NOT resonate, it is a resistive LOAD designed to burn up the power by turning it into HEAT! Thats why they call it a dummy LOAD! (key word there is LOAD) Man..you guys say you want elmers, if you truely do not understand something, thats ok, there are people who do understand, and more than willing to help. 73 de W4LGH Alan http://www.w4lgh.com
Reply to a comment by : AA4PB on 2007-02-22

at resonance the antenna is inducing more power into the atmosphere ---------------------------------------------------- Can you point us to a definitive text that proves this, or even claims it to be true?
Reply to a comment by : K9IUQ on 2007-02-22

One TRUE statement was made, a RESONATE antenna will work BETTER than a NON_RESONATE antenna. People do NOT understand resonance ..................................................... The above is an false statement. An Antenna is resonant at ONLY ONE frequency. At any other frequency it is non-resonant. We all use non-resonant antennas (including you) on a daily basis. We make the antenna SYSTEM resonant with a tuner of one kind or another or live with SWR higher than 1:1. Agreed - the whole SYSTEM must be resonance -from the radio to the antenna. It makes little difference if the antenna itself is resonance or not.Many of the best performing wire antennas are non-resonant fed with open wire feeders and an antenna tuner. Also resonance of the SYSTEM has nothing to do with how well the antenna radiates. This is determined by MANY other factors. I have a wonderful Dummy load antenna under my desk that is resonant on all HF bands, however it doesnt seem to radiate very well since I haven't worked too many people with it. Please Pick Up an antenna Book like "Reflections" and learn the facts instead of trying to sell me 'some wonderful ocean front property in Arizona " K9IUQ
W4LGH2007-02-22
RE: No Myth
W6TH Vito wrote.. ~"W4LGH Alan, I've heard enough of your bullshit, enough is enough."~

Well Mr Vito...That certainly was an educated response!

I have seen it all in my career, from a 5 gallon bucket of dirt in a guys trunk, because the instructions said "This wire needs to go to EARTH ground", to a station engineer who wouldn't let anyone install any antennas upside down on his tower because he said, RF would leak out.

I guess some people take things to litteral, and some don't take it litteral enough.

A lot of good info in this thread, but again it goes to show you can not POST a good article here on eHam, no matter what, people will try to tear it apart. No one understands friendly debate.

73 de W4LGH - Alan



Reply to a comment by : W6TH on 2007-02-22

. W4LGH Alan, I've heard enough of your bullshit, enough is enough. W6TH .:
Reply to a comment by : W6TH on 2007-02-22

. Frequency = 1 divided by time. Time is relevant. Known as the Black Hole. No Myth. .:
Reply to a comment by : N3OX on 2007-02-22

"But the tuner was at the antenna feed point, matching the antenna impedance to the radio, it worked, and I certainly didn't have extra power to spare, but it would have worked BETTER, had the wire been resonant on the frequency I was using" Untrue.
Reply to a comment by : N3OX on 2007-02-22

W4LGH: The excerpt you quoted from that page explains that a center fed antenna has the lowest possible impedance when it's half-wave resonant (or three-halves or five halves, whatever); that is, if you fix the ***voltage*** you feed to an antenna, you'll get the most current, and therefore the biggest field, when it's an odd multiple of a half wave. If you force the same current in a similar, but nonresonant antenna, you get the same strength field (up to the antenna being a little bit shorter or longer which affects its gain in a minor fashion). If you had a magical transistor or tube that didn't care if the voltage was not in phase with the current and didn't care how high that voltage got, you would never have to match to a nonresonant antenna. We always say that we're "transforming the antenna impedance" with a network, but we could equally say "we're transforming the transmitter output up to a voltage with the proper phase to drive the a particular current into the antenna impedance" An article I found that's more precise: http://www.cv.nrao.edu/course/astr534/AntennaTheory.html There's a bunch of stuff later on that isn't particularly applicable to our current discussion, like the impedance of a black hole, but they do talk about reciprocity later on in the page. 73, Dan
Reply to a comment by : W6TH on 2007-02-22

. W4LGH We have been talking about transmitting antennas, I would like to know a specific purpose for using a non-resonant antenna on a transmitter. ..................................................... A long-wire antenna radiates more power in its most favorable direction than does a half wave resonant antenna in its most favorable direction. This power gain is secured at the expense of radiation in other directions. Would you like me to run some analytical Geometry for you? Maybe my math can convince you. Better yet, lets see what your math can do for me. 73, W6TH .:
Reply to a comment by : W4LGH on 2007-02-22

W6TH wrote..."This is no myth, but the truth. A resonant antenna and a non resonant antenna are both efficient antennas; non are better than the other, each has its own purpose for use." We have been talking about transmitting antennas, I would like to know a specific purpose for using a non-resonant antenna on a transmitter. If one truely understands resonance, I don't understand how anything can be as efficient as one that is resonant. And it is proven to you everytime you load up a transmitter. I certainly understand that weird things will work, but that doesn't make it so. I worked over 15 countries running 3 watts or less into a 50' wire fed at the end with an MFJ 16010 tuner. But the tuner was at the antenna feed point, matching the antenna impedance to the radio, it worked, and I certainly didn't have extra power to spare, but it would have worked BETTER, had the wire been resonant on the frequency I was using, certainly more efficient, as at resonancde the end of the wire looks like an open circuit, where as off resonance it begins to look like a short. 73 de W4LGH Alan http://www.w4lgh.com
Reply to a comment by : W6TH on 2007-02-22

. This is no myth, but the truth. A resonant antenna and a non resonant antenna are both efficient antennas; non are better than the other, each has its own purpose for use. W6TH .:
Reply to a comment by : WB2WIK on 2007-02-22

Not all solid state rigs reduce output power beginning at VSWR = 1.5. That is ultra conservative. The Ten Tec transceivers for years used a circuit breaker in the power supply to tell the transceiver when to "cut back power" due to high VSWR. They'd shut off! But until the breaker tripped, they'd keep transmitting. My Drake TR-7, by published specification, provides 90% of its full rated output power into a 2:1 VSWR and doesn't "fold back" to 50% (which is still about 75W output power) until VSWR = 5:1. That detail is listed here on the last page of the TR-7 brochure: http://wb4hfn.com/DRAKE/DrakeCatalogsBrochures/Brochure_TR7_04B.htm As such, the TR-7 hardly needs a tuner unless the user intends some pretty serious mismatches. Mine can easily produce 100W output power into a 3:1 mismatch, on any band. Without a tuner. It's largely a matter of "headroom" for the power amplifying devices selected. Margins include current, voltage and heat. One problem with a little rig like the FT-857 is its PA devices are small and its PA heatsink is *very* small, not capable of carrying much heat away from the devices, even with a fan. The TR-7 power amplifier heatsink alone (just the heatsink) is larger than the entire FT-857... WB2WIK/6
Reply to a comment by : K6HWH on 2007-02-22

"Every solidstate radio I have ever owned started shutting down power at a 1.5 swr." What about this? I have a Yaesu 857 that does indeed crank down transmit power if the SWR is the least bit off, ostensibly to prevent damage to the output transistors. If even a SWR of 5 does not diminish appreciable the antenna's ability to radiate, isn't this a mistake? Should I be looking for a way to defeat the 857's cautious approach to SWR?
Reply to a comment by : K3AN on 2007-02-22

This article is evidence that you can't determine the usefulness or accuracy of an article by the number of words. If you want useful, accurate information on antennas, please visit the L.B. Cebik web site www.cebik.com. For the last time, there is nothing magical about resonant antennas.
Reply to a comment by : N3OX on 2007-02-22

Respectfully, W4LGH, I would like to point out that you are the one muddying the waters about a *resonant antenna* and its radiating effectiveness. It is not true that antenna element resonance has anything to do with coupling power into the electromagnetic field around the antenna. The *REAL* part of the antenna impedance has two components, the radiation resistance and the loss resistance. That fraction of the power which is associated with "dissipation" in the radiation resistance is the power that gets radiated. The fraction associated with dissipation in the loss resistance goes up as heat. The power in the reactive part of the impedance is simply stored in fields around the antenna. That means that an antenna with an impedance of 70+j0 and one with an impedance of 70+j500 are radiating exactly the same amount of power if you can feed that power to them in the first place. You need to match the antenna system to the transmitter but resonance of the antenna element itself has nothing at all to do with the transfer of that power to radiating electromagnetic fields. If you are supplying 100W to the antenna, 100W minus the antenna losses is radiated, no matter whether or not the antenna element is resonant. 73, Dan
Reply to a comment by : W4LGH on 2007-02-22

You see, here we go again, a good article is written, it contains some great info. Some additional articles are written taken it a little further. Then come the people who truely do not understand what is being said, and either go on what they have seen, or what somebody else who truely doesn't understand told them. ==================================================== Now... AA4PB writes..."at resonance the antenna is inducing more power into the atmosphere ---------------------------------------------------- Can you point us to a definitive text that proves this, or even claims it to be true?" ==================================================== Now with a call like this, this guy is at least an "ADVANCED" class if not an "EXTRA" class, what I said is basic "Physics 101" Resonance is a common thread which runs through almost every branch of physics, and yet a lot of people have never studied it. Without resonance we wouldn't have radio, television, music, or swings on playgrounds, not to mention cool gismos like Tesla coils. Of course, resonance also has its dark side. It occasionally causes a bridge to collapse, a helicopter to fly apart, or other inconveniences. Unlike black holes, time travel, and quantum mechanics, resonance is common place and easy to observe. Yet, it is one of the most striking and unexpected phenomenon in all of physics. It is relative to everything. Here is a good link to read about it...hopefully it will explain.. http://www.intuitor.com/resonance/circuits.html Ever heard the term, "Dip the Plate" when tuning? Notice how the plate current drops but your output increases? Wonder why that is? Could it be your tank circuit has been tuned to resonance? Hmmm...your antenna is an extension of your tank circuit. And to K9IUQ...who wrote..."Also resonance of the SYSTEM has nothing to do with how well the antenna radiates. This is determined by MANY other factors. I have a wonderful Dummy load antenna under my desk that is resonant on all HF bands, however it doesnt seem to radiate very well since I haven't worked too many people with it."... I give up here, this guy just isn't with the program...A dummy LOAD is NOT resonate, it is a resistive LOAD designed to burn up the power by turning it into HEAT! Thats why they call it a dummy LOAD! (key word there is LOAD) Man..you guys say you want elmers, if you truely do not understand something, thats ok, there are people who do understand, and more than willing to help. 73 de W4LGH Alan http://www.w4lgh.com
Reply to a comment by : AA4PB on 2007-02-22

at resonance the antenna is inducing more power into the atmosphere ---------------------------------------------------- Can you point us to a definitive text that proves this, or even claims it to be true?
Reply to a comment by : K9IUQ on 2007-02-22

One TRUE statement was made, a RESONATE antenna will work BETTER than a NON_RESONATE antenna. People do NOT understand resonance ..................................................... The above is an false statement. An Antenna is resonant at ONLY ONE frequency. At any other frequency it is non-resonant. We all use non-resonant antennas (including you) on a daily basis. We make the antenna SYSTEM resonant with a tuner of one kind or another or live with SWR higher than 1:1. Agreed - the whole SYSTEM must be resonance -from the radio to the antenna. It makes little difference if the antenna itself is resonance or not.Many of the best performing wire antennas are non-resonant fed with open wire feeders and an antenna tuner. Also resonance of the SYSTEM has nothing to do with how well the antenna radiates. This is determined by MANY other factors. I have a wonderful Dummy load antenna under my desk that is resonant on all HF bands, however it doesnt seem to radiate very well since I haven't worked too many people with it. Please Pick Up an antenna Book like "Reflections" and learn the facts instead of trying to sell me 'some wonderful ocean front property in Arizona " K9IUQ
W6TH2007-02-22
RE: No Myth
.

W4LGH Alan,

I've heard enough of your bullshit, enough is enough.

W6TH
.:
Reply to a comment by : W6TH on 2007-02-22

. Frequency = 1 divided by time. Time is relevant. Known as the Black Hole. No Myth. .:
Reply to a comment by : N3OX on 2007-02-22

"But the tuner was at the antenna feed point, matching the antenna impedance to the radio, it worked, and I certainly didn't have extra power to spare, but it would have worked BETTER, had the wire been resonant on the frequency I was using" Untrue.
Reply to a comment by : N3OX on 2007-02-22

W4LGH: The excerpt you quoted from that page explains that a center fed antenna has the lowest possible impedance when it's half-wave resonant (or three-halves or five halves, whatever); that is, if you fix the ***voltage*** you feed to an antenna, you'll get the most current, and therefore the biggest field, when it's an odd multiple of a half wave. If you force the same current in a similar, but nonresonant antenna, you get the same strength field (up to the antenna being a little bit shorter or longer which affects its gain in a minor fashion). If you had a magical transistor or tube that didn't care if the voltage was not in phase with the current and didn't care how high that voltage got, you would never have to match to a nonresonant antenna. We always say that we're "transforming the antenna impedance" with a network, but we could equally say "we're transforming the transmitter output up to a voltage with the proper phase to drive the a particular current into the antenna impedance" An article I found that's more precise: http://www.cv.nrao.edu/course/astr534/AntennaTheory.html There's a bunch of stuff later on that isn't particularly applicable to our current discussion, like the impedance of a black hole, but they do talk about reciprocity later on in the page. 73, Dan
Reply to a comment by : W6TH on 2007-02-22

. W4LGH We have been talking about transmitting antennas, I would like to know a specific purpose for using a non-resonant antenna on a transmitter. ..................................................... A long-wire antenna radiates more power in its most favorable direction than does a half wave resonant antenna in its most favorable direction. This power gain is secured at the expense of radiation in other directions. Would you like me to run some analytical Geometry for you? Maybe my math can convince you. Better yet, lets see what your math can do for me. 73, W6TH .:
Reply to a comment by : W4LGH on 2007-02-22

W6TH wrote..."This is no myth, but the truth. A resonant antenna and a non resonant antenna are both efficient antennas; non are better than the other, each has its own purpose for use." We have been talking about transmitting antennas, I would like to know a specific purpose for using a non-resonant antenna on a transmitter. If one truely understands resonance, I don't understand how anything can be as efficient as one that is resonant. And it is proven to you everytime you load up a transmitter. I certainly understand that weird things will work, but that doesn't make it so. I worked over 15 countries running 3 watts or less into a 50' wire fed at the end with an MFJ 16010 tuner. But the tuner was at the antenna feed point, matching the antenna impedance to the radio, it worked, and I certainly didn't have extra power to spare, but it would have worked BETTER, had the wire been resonant on the frequency I was using, certainly more efficient, as at resonancde the end of the wire looks like an open circuit, where as off resonance it begins to look like a short. 73 de W4LGH Alan http://www.w4lgh.com
Reply to a comment by : W6TH on 2007-02-22

. This is no myth, but the truth. A resonant antenna and a non resonant antenna are both efficient antennas; non are better than the other, each has its own purpose for use. W6TH .:
Reply to a comment by : WB2WIK on 2007-02-22

Not all solid state rigs reduce output power beginning at VSWR = 1.5. That is ultra conservative. The Ten Tec transceivers for years used a circuit breaker in the power supply to tell the transceiver when to "cut back power" due to high VSWR. They'd shut off! But until the breaker tripped, they'd keep transmitting. My Drake TR-7, by published specification, provides 90% of its full rated output power into a 2:1 VSWR and doesn't "fold back" to 50% (which is still about 75W output power) until VSWR = 5:1. That detail is listed here on the last page of the TR-7 brochure: http://wb4hfn.com/DRAKE/DrakeCatalogsBrochures/Brochure_TR7_04B.htm As such, the TR-7 hardly needs a tuner unless the user intends some pretty serious mismatches. Mine can easily produce 100W output power into a 3:1 mismatch, on any band. Without a tuner. It's largely a matter of "headroom" for the power amplifying devices selected. Margins include current, voltage and heat. One problem with a little rig like the FT-857 is its PA devices are small and its PA heatsink is *very* small, not capable of carrying much heat away from the devices, even with a fan. The TR-7 power amplifier heatsink alone (just the heatsink) is larger than the entire FT-857... WB2WIK/6
Reply to a comment by : K6HWH on 2007-02-22

"Every solidstate radio I have ever owned started shutting down power at a 1.5 swr." What about this? I have a Yaesu 857 that does indeed crank down transmit power if the SWR is the least bit off, ostensibly to prevent damage to the output transistors. If even a SWR of 5 does not diminish appreciable the antenna's ability to radiate, isn't this a mistake? Should I be looking for a way to defeat the 857's cautious approach to SWR?
Reply to a comment by : K3AN on 2007-02-22

This article is evidence that you can't determine the usefulness or accuracy of an article by the number of words. If you want useful, accurate information on antennas, please visit the L.B. Cebik web site www.cebik.com. For the last time, there is nothing magical about resonant antennas.
Reply to a comment by : N3OX on 2007-02-22

Respectfully, W4LGH, I would like to point out that you are the one muddying the waters about a *resonant antenna* and its radiating effectiveness. It is not true that antenna element resonance has anything to do with coupling power into the electromagnetic field around the antenna. The *REAL* part of the antenna impedance has two components, the radiation resistance and the loss resistance. That fraction of the power which is associated with "dissipation" in the radiation resistance is the power that gets radiated. The fraction associated with dissipation in the loss resistance goes up as heat. The power in the reactive part of the impedance is simply stored in fields around the antenna. That means that an antenna with an impedance of 70+j0 and one with an impedance of 70+j500 are radiating exactly the same amount of power if you can feed that power to them in the first place. You need to match the antenna system to the transmitter but resonance of the antenna element itself has nothing at all to do with the transfer of that power to radiating electromagnetic fields. If you are supplying 100W to the antenna, 100W minus the antenna losses is radiated, no matter whether or not the antenna element is resonant. 73, Dan
Reply to a comment by : W4LGH on 2007-02-22

You see, here we go again, a good article is written, it contains some great info. Some additional articles are written taken it a little further. Then come the people who truely do not understand what is being said, and either go on what they have seen, or what somebody else who truely doesn't understand told them. ==================================================== Now... AA4PB writes..."at resonance the antenna is inducing more power into the atmosphere ---------------------------------------------------- Can you point us to a definitive text that proves this, or even claims it to be true?" ==================================================== Now with a call like this, this guy is at least an "ADVANCED" class if not an "EXTRA" class, what I said is basic "Physics 101" Resonance is a common thread which runs through almost every branch of physics, and yet a lot of people have never studied it. Without resonance we wouldn't have radio, television, music, or swings on playgrounds, not to mention cool gismos like Tesla coils. Of course, resonance also has its dark side. It occasionally causes a bridge to collapse, a helicopter to fly apart, or other inconveniences. Unlike black holes, time travel, and quantum mechanics, resonance is common place and easy to observe. Yet, it is one of the most striking and unexpected phenomenon in all of physics. It is relative to everything. Here is a good link to read about it...hopefully it will explain.. http://www.intuitor.com/resonance/circuits.html Ever heard the term, "Dip the Plate" when tuning? Notice how the plate current drops but your output increases? Wonder why that is? Could it be your tank circuit has been tuned to resonance? Hmmm...your antenna is an extension of your tank circuit. And to K9IUQ...who wrote..."Also resonance of the SYSTEM has nothing to do with how well the antenna radiates. This is determined by MANY other factors. I have a wonderful Dummy load antenna under my desk that is resonant on all HF bands, however it doesnt seem to radiate very well since I haven't worked too many people with it."... I give up here, this guy just isn't with the program...A dummy LOAD is NOT resonate, it is a resistive LOAD designed to burn up the power by turning it into HEAT! Thats why they call it a dummy LOAD! (key word there is LOAD) Man..you guys say you want elmers, if you truely do not understand something, thats ok, there are people who do understand, and more than willing to help. 73 de W4LGH Alan http://www.w4lgh.com
Reply to a comment by : AA4PB on 2007-02-22

at resonance the antenna is inducing more power into the atmosphere ---------------------------------------------------- Can you point us to a definitive text that proves this, or even claims it to be true?
Reply to a comment by : K9IUQ on 2007-02-22

One TRUE statement was made, a RESONATE antenna will work BETTER than a NON_RESONATE antenna. People do NOT understand resonance ..................................................... The above is an false statement. An Antenna is resonant at ONLY ONE frequency. At any other frequency it is non-resonant. We all use non-resonant antennas (including you) on a daily basis. We make the antenna SYSTEM resonant with a tuner of one kind or another or live with SWR higher than 1:1. Agreed - the whole SYSTEM must be resonance -from the radio to the antenna. It makes little difference if the antenna itself is resonance or not.Many of the best performing wire antennas are non-resonant fed with open wire feeders and an antenna tuner. Also resonance of the SYSTEM has nothing to do with how well the antenna radiates. This is determined by MANY other factors. I have a wonderful Dummy load antenna under my desk that is resonant on all HF bands, however it doesnt seem to radiate very well since I haven't worked too many people with it. Please Pick Up an antenna Book like "Reflections" and learn the facts instead of trying to sell me 'some wonderful ocean front property in Arizona " K9IUQ
W6TH2007-02-22
RE: No Myth
.

Frequency = 1 divided by time. Time is relevant.


Known as the Black Hole.

No Myth.
.:
Reply to a comment by : N3OX on 2007-02-22

"But the tuner was at the antenna feed point, matching the antenna impedance to the radio, it worked, and I certainly didn't have extra power to spare, but it would have worked BETTER, had the wire been resonant on the frequency I was using" Untrue.
Reply to a comment by : N3OX on 2007-02-22

W4LGH: The excerpt you quoted from that page explains that a center fed antenna has the lowest possible impedance when it's half-wave resonant (or three-halves or five halves, whatever); that is, if you fix the ***voltage*** you feed to an antenna, you'll get the most current, and therefore the biggest field, when it's an odd multiple of a half wave. If you force the same current in a similar, but nonresonant antenna, you get the same strength field (up to the antenna being a little bit shorter or longer which affects its gain in a minor fashion). If you had a magical transistor or tube that didn't care if the voltage was not in phase with the current and didn't care how high that voltage got, you would never have to match to a nonresonant antenna. We always say that we're "transforming the antenna impedance" with a network, but we could equally say "we're transforming the transmitter output up to a voltage with the proper phase to drive the a particular current into the antenna impedance" An article I found that's more precise: http://www.cv.nrao.edu/course/astr534/AntennaTheory.html There's a bunch of stuff later on that isn't particularly applicable to our current discussion, like the impedance of a black hole, but they do talk about reciprocity later on in the page. 73, Dan
Reply to a comment by : W6TH on 2007-02-22

. W4LGH We have been talking about transmitting antennas, I would like to know a specific purpose for using a non-resonant antenna on a transmitter. ..................................................... A long-wire antenna radiates more power in its most favorable direction than does a half wave resonant antenna in its most favorable direction. This power gain is secured at the expense of radiation in other directions. Would you like me to run some analytical Geometry for you? Maybe my math can convince you. Better yet, lets see what your math can do for me. 73, W6TH .:
Reply to a comment by : W4LGH on 2007-02-22

W6TH wrote..."This is no myth, but the truth. A resonant antenna and a non resonant antenna are both efficient antennas; non are better than the other, each has its own purpose for use." We have been talking about transmitting antennas, I would like to know a specific purpose for using a non-resonant antenna on a transmitter. If one truely understands resonance, I don't understand how anything can be as efficient as one that is resonant. And it is proven to you everytime you load up a transmitter. I certainly understand that weird things will work, but that doesn't make it so. I worked over 15 countries running 3 watts or less into a 50' wire fed at the end with an MFJ 16010 tuner. But the tuner was at the antenna feed point, matching the antenna impedance to the radio, it worked, and I certainly didn't have extra power to spare, but it would have worked BETTER, had the wire been resonant on the frequency I was using, certainly more efficient, as at resonancde the end of the wire looks like an open circuit, where as off resonance it begins to look like a short. 73 de W4LGH Alan http://www.w4lgh.com
Reply to a comment by : W6TH on 2007-02-22

. This is no myth, but the truth. A resonant antenna and a non resonant antenna are both efficient antennas; non are better than the other, each has its own purpose for use. W6TH .:
Reply to a comment by : WB2WIK on 2007-02-22

Not all solid state rigs reduce output power beginning at VSWR = 1.5. That is ultra conservative. The Ten Tec transceivers for years used a circuit breaker in the power supply to tell the transceiver when to "cut back power" due to high VSWR. They'd shut off! But until the breaker tripped, they'd keep transmitting. My Drake TR-7, by published specification, provides 90% of its full rated output power into a 2:1 VSWR and doesn't "fold back" to 50% (which is still about 75W output power) until VSWR = 5:1. That detail is listed here on the last page of the TR-7 brochure: http://wb4hfn.com/DRAKE/DrakeCatalogsBrochures/Brochure_TR7_04B.htm As such, the TR-7 hardly needs a tuner unless the user intends some pretty serious mismatches. Mine can easily produce 100W output power into a 3:1 mismatch, on any band. Without a tuner. It's largely a matter of "headroom" for the power amplifying devices selected. Margins include current, voltage and heat. One problem with a little rig like the FT-857 is its PA devices are small and its PA heatsink is *very* small, not capable of carrying much heat away from the devices, even with a fan. The TR-7 power amplifier heatsink alone (just the heatsink) is larger than the entire FT-857... WB2WIK/6
Reply to a comment by : K6HWH on 2007-02-22

"Every solidstate radio I have ever owned started shutting down power at a 1.5 swr." What about this? I have a Yaesu 857 that does indeed crank down transmit power if the SWR is the least bit off, ostensibly to prevent damage to the output transistors. If even a SWR of 5 does not diminish appreciable the antenna's ability to radiate, isn't this a mistake? Should I be looking for a way to defeat the 857's cautious approach to SWR?
Reply to a comment by : K3AN on 2007-02-22

This article is evidence that you can't determine the usefulness or accuracy of an article by the number of words. If you want useful, accurate information on antennas, please visit the L.B. Cebik web site www.cebik.com. For the last time, there is nothing magical about resonant antennas.
Reply to a comment by : N3OX on 2007-02-22

Respectfully, W4LGH, I would like to point out that you are the one muddying the waters about a *resonant antenna* and its radiating effectiveness. It is not true that antenna element resonance has anything to do with coupling power into the electromagnetic field around the antenna. The *REAL* part of the antenna impedance has two components, the radiation resistance and the loss resistance. That fraction of the power which is associated with "dissipation" in the radiation resistance is the power that gets radiated. The fraction associated with dissipation in the loss resistance goes up as heat. The power in the reactive part of the impedance is simply stored in fields around the antenna. That means that an antenna with an impedance of 70+j0 and one with an impedance of 70+j500 are radiating exactly the same amount of power if you can feed that power to them in the first place. You need to match the antenna system to the transmitter but resonance of the antenna element itself has nothing at all to do with the transfer of that power to radiating electromagnetic fields. If you are supplying 100W to the antenna, 100W minus the antenna losses is radiated, no matter whether or not the antenna element is resonant. 73, Dan
Reply to a comment by : W4LGH on 2007-02-22

You see, here we go again, a good article is written, it contains some great info. Some additional articles are written taken it a little further. Then come the people who truely do not understand what is being said, and either go on what they have seen, or what somebody else who truely doesn't understand told them. ==================================================== Now... AA4PB writes..."at resonance the antenna is inducing more power into the atmosphere ---------------------------------------------------- Can you point us to a definitive text that proves this, or even claims it to be true?" ==================================================== Now with a call like this, this guy is at least an "ADVANCED" class if not an "EXTRA" class, what I said is basic "Physics 101" Resonance is a common thread which runs through almost every branch of physics, and yet a lot of people have never studied it. Without resonance we wouldn't have radio, television, music, or swings on playgrounds, not to mention cool gismos like Tesla coils. Of course, resonance also has its dark side. It occasionally causes a bridge to collapse, a helicopter to fly apart, or other inconveniences. Unlike black holes, time travel, and quantum mechanics, resonance is common place and easy to observe. Yet, it is one of the most striking and unexpected phenomenon in all of physics. It is relative to everything. Here is a good link to read about it...hopefully it will explain.. http://www.intuitor.com/resonance/circuits.html Ever heard the term, "Dip the Plate" when tuning? Notice how the plate current drops but your output increases? Wonder why that is? Could it be your tank circuit has been tuned to resonance? Hmmm...your antenna is an extension of your tank circuit. And to K9IUQ...who wrote..."Also resonance of the SYSTEM has nothing to do with how well the antenna radiates. This is determined by MANY other factors. I have a wonderful Dummy load antenna under my desk that is resonant on all HF bands, however it doesnt seem to radiate very well since I haven't worked too many people with it."... I give up here, this guy just isn't with the program...A dummy LOAD is NOT resonate, it is a resistive LOAD designed to burn up the power by turning it into HEAT! Thats why they call it a dummy LOAD! (key word there is LOAD) Man..you guys say you want elmers, if you truely do not understand something, thats ok, there are people who do understand, and more than willing to help. 73 de W4LGH Alan http://www.w4lgh.com
Reply to a comment by : AA4PB on 2007-02-22

at resonance the antenna is inducing more power into the atmosphere ---------------------------------------------------- Can you point us to a definitive text that proves this, or even claims it to be true?
Reply to a comment by : K9IUQ on 2007-02-22

One TRUE statement was made, a RESONATE antenna will work BETTER than a NON_RESONATE antenna. People do NOT understand resonance ..................................................... The above is an false statement. An Antenna is resonant at ONLY ONE frequency. At any other frequency it is non-resonant. We all use non-resonant antennas (including you) on a daily basis. We make the antenna SYSTEM resonant with a tuner of one kind or another or live with SWR higher than 1:1. Agreed - the whole SYSTEM must be resonance -from the radio to the antenna. It makes little difference if the antenna itself is resonance or not.Many of the best performing wire antennas are non-resonant fed with open wire feeders and an antenna tuner. Also resonance of the SYSTEM has nothing to do with how well the antenna radiates. This is determined by MANY other factors. I have a wonderful Dummy load antenna under my desk that is resonant on all HF bands, however it doesnt seem to radiate very well since I haven't worked too many people with it. Please Pick Up an antenna Book like "Reflections" and learn the facts instead of trying to sell me 'some wonderful ocean front property in Arizona " K9IUQ
W4LGH2007-02-22
RE: No Myth
W6TH wrote..."A long-wire antenna radiates more power in its most favorable direction than does a half wave resonant antenna in its most favorable direction. This power gain is secured at the expense of radiation in other directions.
Would you like me to run some analytical Geometry for you? Maybe my math can convince you.
Better yet, lets see what your math can do for me."

=====

This is getting good now...In order for a long wire antenna to show GAIN in a favorable direction, the antenna has to be resonant on the main frequency or some equal multiples of the main frequency, such as 2 wavelengths, or 3wavelengths etc. That being the case, then the antenna is resonant and your long wire antenna becomes a multi-phased array which beams more signal in one direction. Now an odd length wire say 2.5 wavelengths of the operating freq. will have 2 resonant sections which are in phase, with a non-resonant section to decouple the 2 in-phase and you can control the direction you beam it.

I don't care about your math, anymore than you can about mine. I am an engineer and have done the math. I will also tell you that there is NOT a commercial installation of any broadcast systems out there that would use non-resonant antenna! Been in the broadcast industry to long to know better. So I am still waiting on an example for the use of a non-resonant antenna hooked to a transmitter. Unless what I said above is what you were trying to say, but didn't.

And if N9IUQ wore the covers off the Reflections, it must have been from looking at the pictures and not from reading the text, from the comments he has made. Not picking on you, just observations made from your own comments.
Those who live in Glass houses shouldn't throw stones!


73 de W4LGH Alan
http://www.w4lgh.com


Reply to a comment by : W6TH on 2007-02-22

. W4LGH We have been talking about transmitting antennas, I would like to know a specific purpose for using a non-resonant antenna on a transmitter. ..................................................... A long-wire antenna radiates more power in its most favorable direction than does a half wave resonant antenna in its most favorable direction. This power gain is secured at the expense of radiation in other directions. Would you like me to run some analytical Geometry for you? Maybe my math can convince you. Better yet, lets see what your math can do for me. 73, W6TH .:
Reply to a comment by : W4LGH on 2007-02-22

W6TH wrote..."This is no myth, but the truth. A resonant antenna and a non resonant antenna are both efficient antennas; non are better than the other, each has its own purpose for use." We have been talking about transmitting antennas, I would like to know a specific purpose for using a non-resonant antenna on a transmitter. If one truely understands resonance, I don't understand how anything can be as efficient as one that is resonant. And it is proven to you everytime you load up a transmitter. I certainly understand that weird things will work, but that doesn't make it so. I worked over 15 countries running 3 watts or less into a 50' wire fed at the end with an MFJ 16010 tuner. But the tuner was at the antenna feed point, matching the antenna impedance to the radio, it worked, and I certainly didn't have extra power to spare, but it would have worked BETTER, had the wire been resonant on the frequency I was using, certainly more efficient, as at resonancde the end of the wire looks like an open circuit, where as off resonance it begins to look like a short. 73 de W4LGH Alan http://www.w4lgh.com
Reply to a comment by : W6TH on 2007-02-22

. This is no myth, but the truth. A resonant antenna and a non resonant antenna are both efficient antennas; non are better than the other, each has its own purpose for use. W6TH .:
Reply to a comment by : WB2WIK on 2007-02-22

Not all solid state rigs reduce output power beginning at VSWR = 1.5. That is ultra conservative. The Ten Tec transceivers for years used a circuit breaker in the power supply to tell the transceiver when to "cut back power" due to high VSWR. They'd shut off! But until the breaker tripped, they'd keep transmitting. My Drake TR-7, by published specification, provides 90% of its full rated output power into a 2:1 VSWR and doesn't "fold back" to 50% (which is still about 75W output power) until VSWR = 5:1. That detail is listed here on the last page of the TR-7 brochure: http://wb4hfn.com/DRAKE/DrakeCatalogsBrochures/Brochure_TR7_04B.htm As such, the TR-7 hardly needs a tuner unless the user intends some pretty serious mismatches. Mine can easily produce 100W output power into a 3:1 mismatch, on any band. Without a tuner. It's largely a matter of "headroom" for the power amplifying devices selected. Margins include current, voltage and heat. One problem with a little rig like the FT-857 is its PA devices are small and its PA heatsink is *very* small, not capable of carrying much heat away from the devices, even with a fan. The TR-7 power amplifier heatsink alone (just the heatsink) is larger than the entire FT-857... WB2WIK/6
Reply to a comment by : K6HWH on 2007-02-22

"Every solidstate radio I have ever owned started shutting down power at a 1.5 swr." What about this? I have a Yaesu 857 that does indeed crank down transmit power if the SWR is the least bit off, ostensibly to prevent damage to the output transistors. If even a SWR of 5 does not diminish appreciable the antenna's ability to radiate, isn't this a mistake? Should I be looking for a way to defeat the 857's cautious approach to SWR?
Reply to a comment by : K3AN on 2007-02-22

This article is evidence that you can't determine the usefulness or accuracy of an article by the number of words. If you want useful, accurate information on antennas, please visit the L.B. Cebik web site www.cebik.com. For the last time, there is nothing magical about resonant antennas.
Reply to a comment by : N3OX on 2007-02-22

Respectfully, W4LGH, I would like to point out that you are the one muddying the waters about a *resonant antenna* and its radiating effectiveness. It is not true that antenna element resonance has anything to do with coupling power into the electromagnetic field around the antenna. The *REAL* part of the antenna impedance has two components, the radiation resistance and the loss resistance. That fraction of the power which is associated with "dissipation" in the radiation resistance is the power that gets radiated. The fraction associated with dissipation in the loss resistance goes up as heat. The power in the reactive part of the impedance is simply stored in fields around the antenna. That means that an antenna with an impedance of 70+j0 and one with an impedance of 70+j500 are radiating exactly the same amount of power if you can feed that power to them in the first place. You need to match the antenna system to the transmitter but resonance of the antenna element itself has nothing at all to do with the transfer of that power to radiating electromagnetic fields. If you are supplying 100W to the antenna, 100W minus the antenna losses is radiated, no matter whether or not the antenna element is resonant. 73, Dan
Reply to a comment by : W4LGH on 2007-02-22

You see, here we go again, a good article is written, it contains some great info. Some additional articles are written taken it a little further. Then come the people who truely do not understand what is being said, and either go on what they have seen, or what somebody else who truely doesn't understand told them. ==================================================== Now... AA4PB writes..."at resonance the antenna is inducing more power into the atmosphere ---------------------------------------------------- Can you point us to a definitive text that proves this, or even claims it to be true?" ==================================================== Now with a call like this, this guy is at least an "ADVANCED" class if not an "EXTRA" class, what I said is basic "Physics 101" Resonance is a common thread which runs through almost every branch of physics, and yet a lot of people have never studied it. Without resonance we wouldn't have radio, television, music, or swings on playgrounds, not to mention cool gismos like Tesla coils. Of course, resonance also has its dark side. It occasionally causes a bridge to collapse, a helicopter to fly apart, or other inconveniences. Unlike black holes, time travel, and quantum mechanics, resonance is common place and easy to observe. Yet, it is one of the most striking and unexpected phenomenon in all of physics. It is relative to everything. Here is a good link to read about it...hopefully it will explain.. http://www.intuitor.com/resonance/circuits.html Ever heard the term, "Dip the Plate" when tuning? Notice how the plate current drops but your output increases? Wonder why that is? Could it be your tank circuit has been tuned to resonance? Hmmm...your antenna is an extension of your tank circuit. And to K9IUQ...who wrote..."Also resonance of the SYSTEM has nothing to do with how well the antenna radiates. This is determined by MANY other factors. I have a wonderful Dummy load antenna under my desk that is resonant on all HF bands, however it doesnt seem to radiate very well since I haven't worked too many people with it."... I give up here, this guy just isn't with the program...A dummy LOAD is NOT resonate, it is a resistive LOAD designed to burn up the power by turning it into HEAT! Thats why they call it a dummy LOAD! (key word there is LOAD) Man..you guys say you want elmers, if you truely do not understand something, thats ok, there are people who do understand, and more than willing to help. 73 de W4LGH Alan http://www.w4lgh.com
Reply to a comment by : AA4PB on 2007-02-22

at resonance the antenna is inducing more power into the atmosphere ---------------------------------------------------- Can you point us to a definitive text that proves this, or even claims it to be true?
Reply to a comment by : K9IUQ on 2007-02-22

One TRUE statement was made, a RESONATE antenna will work BETTER than a NON_RESONATE antenna. People do NOT understand resonance ..................................................... The above is an false statement. An Antenna is resonant at ONLY ONE frequency. At any other frequency it is non-resonant. We all use non-resonant antennas (including you) on a daily basis. We make the antenna SYSTEM resonant with a tuner of one kind or another or live with SWR higher than 1:1. Agreed - the whole SYSTEM must be resonance -from the radio to the antenna. It makes little difference if the antenna itself is resonance or not.Many of the best performing wire antennas are non-resonant fed with open wire feeders and an antenna tuner. Also resonance of the SYSTEM has nothing to do with how well the antenna radiates. This is determined by MANY other factors. I have a wonderful Dummy load antenna under my desk that is resonant on all HF bands, however it doesnt seem to radiate very well since I haven't worked too many people with it. Please Pick Up an antenna Book like "Reflections" and learn the facts instead of trying to sell me 'some wonderful ocean front property in Arizona " K9IUQ
N3OX2007-02-22
RE: No Myth
"But the tuner was at the antenna feed point, matching the antenna impedance to the radio, it worked, and I certainly didn't have extra power to spare, but it would have worked BETTER, had the wire been resonant on the frequency I was using"

Untrue.
Reply to a comment by : N3OX on 2007-02-22

W4LGH: The excerpt you quoted from that page explains that a center fed antenna has the lowest possible impedance when it's half-wave resonant (or three-halves or five halves, whatever); that is, if you fix the ***voltage*** you feed to an antenna, you'll get the most current, and therefore the biggest field, when it's an odd multiple of a half wave. If you force the same current in a similar, but nonresonant antenna, you get the same strength field (up to the antenna being a little bit shorter or longer which affects its gain in a minor fashion). If you had a magical transistor or tube that didn't care if the voltage was not in phase with the current and didn't care how high that voltage got, you would never have to match to a nonresonant antenna. We always say that we're "transforming the antenna impedance" with a network, but we could equally say "we're transforming the transmitter output up to a voltage with the proper phase to drive the a particular current into the antenna impedance" An article I found that's more precise: http://www.cv.nrao.edu/course/astr534/AntennaTheory.html There's a bunch of stuff later on that isn't particularly applicable to our current discussion, like the impedance of a black hole, but they do talk about reciprocity later on in the page. 73, Dan
Reply to a comment by : W6TH on 2007-02-22

. W4LGH We have been talking about transmitting antennas, I would like to know a specific purpose for using a non-resonant antenna on a transmitter. ..................................................... A long-wire antenna radiates more power in its most favorable direction than does a half wave resonant antenna in its most favorable direction. This power gain is secured at the expense of radiation in other directions. Would you like me to run some analytical Geometry for you? Maybe my math can convince you. Better yet, lets see what your math can do for me. 73, W6TH .:
Reply to a comment by : W4LGH on 2007-02-22

W6TH wrote..."This is no myth, but the truth. A resonant antenna and a non resonant antenna are both efficient antennas; non are better than the other, each has its own purpose for use." We have been talking about transmitting antennas, I would like to know a specific purpose for using a non-resonant antenna on a transmitter. If one truely understands resonance, I don't understand how anything can be as efficient as one that is resonant. And it is proven to you everytime you load up a transmitter. I certainly understand that weird things will work, but that doesn't make it so. I worked over 15 countries running 3 watts or less into a 50' wire fed at the end with an MFJ 16010 tuner. But the tuner was at the antenna feed point, matching the antenna impedance to the radio, it worked, and I certainly didn't have extra power to spare, but it would have worked BETTER, had the wire been resonant on the frequency I was using, certainly more efficient, as at resonancde the end of the wire looks like an open circuit, where as off resonance it begins to look like a short. 73 de W4LGH Alan http://www.w4lgh.com
Reply to a comment by : W6TH on 2007-02-22

. This is no myth, but the truth. A resonant antenna and a non resonant antenna are both efficient antennas; non are better than the other, each has its own purpose for use. W6TH .:
Reply to a comment by : WB2WIK on 2007-02-22

Not all solid state rigs reduce output power beginning at VSWR = 1.5. That is ultra conservative. The Ten Tec transceivers for years used a circuit breaker in the power supply to tell the transceiver when to "cut back power" due to high VSWR. They'd shut off! But until the breaker tripped, they'd keep transmitting. My Drake TR-7, by published specification, provides 90% of its full rated output power into a 2:1 VSWR and doesn't "fold back" to 50% (which is still about 75W output power) until VSWR = 5:1. That detail is listed here on the last page of the TR-7 brochure: http://wb4hfn.com/DRAKE/DrakeCatalogsBrochures/Brochure_TR7_04B.htm As such, the TR-7 hardly needs a tuner unless the user intends some pretty serious mismatches. Mine can easily produce 100W output power into a 3:1 mismatch, on any band. Without a tuner. It's largely a matter of "headroom" for the power amplifying devices selected. Margins include current, voltage and heat. One problem with a little rig like the FT-857 is its PA devices are small and its PA heatsink is *very* small, not capable of carrying much heat away from the devices, even with a fan. The TR-7 power amplifier heatsink alone (just the heatsink) is larger than the entire FT-857... WB2WIK/6
Reply to a comment by : K6HWH on 2007-02-22

"Every solidstate radio I have ever owned started shutting down power at a 1.5 swr." What about this? I have a Yaesu 857 that does indeed crank down transmit power if the SWR is the least bit off, ostensibly to prevent damage to the output transistors. If even a SWR of 5 does not diminish appreciable the antenna's ability to radiate, isn't this a mistake? Should I be looking for a way to defeat the 857's cautious approach to SWR?
Reply to a comment by : K3AN on 2007-02-22

This article is evidence that you can't determine the usefulness or accuracy of an article by the number of words. If you want useful, accurate information on antennas, please visit the L.B. Cebik web site www.cebik.com. For the last time, there is nothing magical about resonant antennas.
Reply to a comment by : N3OX on 2007-02-22

Respectfully, W4LGH, I would like to point out that you are the one muddying the waters about a *resonant antenna* and its radiating effectiveness. It is not true that antenna element resonance has anything to do with coupling power into the electromagnetic field around the antenna. The *REAL* part of the antenna impedance has two components, the radiation resistance and the loss resistance. That fraction of the power which is associated with "dissipation" in the radiation resistance is the power that gets radiated. The fraction associated with dissipation in the loss resistance goes up as heat. The power in the reactive part of the impedance is simply stored in fields around the antenna. That means that an antenna with an impedance of 70+j0 and one with an impedance of 70+j500 are radiating exactly the same amount of power if you can feed that power to them in the first place. You need to match the antenna system to the transmitter but resonance of the antenna element itself has nothing at all to do with the transfer of that power to radiating electromagnetic fields. If you are supplying 100W to the antenna, 100W minus the antenna losses is radiated, no matter whether or not the antenna element is resonant. 73, Dan
Reply to a comment by : W4LGH on 2007-02-22

You see, here we go again, a good article is written, it contains some great info. Some additional articles are written taken it a little further. Then come the people who truely do not understand what is being said, and either go on what they have seen, or what somebody else who truely doesn't understand told them. ==================================================== Now... AA4PB writes..."at resonance the antenna is inducing more power into the atmosphere ---------------------------------------------------- Can you point us to a definitive text that proves this, or even claims it to be true?" ==================================================== Now with a call like this, this guy is at least an "ADVANCED" class if not an "EXTRA" class, what I said is basic "Physics 101" Resonance is a common thread which runs through almost every branch of physics, and yet a lot of people have never studied it. Without resonance we wouldn't have radio, television, music, or swings on playgrounds, not to mention cool gismos like Tesla coils. Of course, resonance also has its dark side. It occasionally causes a bridge to collapse, a helicopter to fly apart, or other inconveniences. Unlike black holes, time travel, and quantum mechanics, resonance is common place and easy to observe. Yet, it is one of the most striking and unexpected phenomenon in all of physics. It is relative to everything. Here is a good link to read about it...hopefully it will explain.. http://www.intuitor.com/resonance/circuits.html Ever heard the term, "Dip the Plate" when tuning? Notice how the plate current drops but your output increases? Wonder why that is? Could it be your tank circuit has been tuned to resonance? Hmmm...your antenna is an extension of your tank circuit. And to K9IUQ...who wrote..."Also resonance of the SYSTEM has nothing to do with how well the antenna radiates. This is determined by MANY other factors. I have a wonderful Dummy load antenna under my desk that is resonant on all HF bands, however it doesnt seem to radiate very well since I haven't worked too many people with it."... I give up here, this guy just isn't with the program...A dummy LOAD is NOT resonate, it is a resistive LOAD designed to burn up the power by turning it into HEAT! Thats why they call it a dummy LOAD! (key word there is LOAD) Man..you guys say you want elmers, if you truely do not understand something, thats ok, there are people who do understand, and more than willing to help. 73 de W4LGH Alan http://www.w4lgh.com
Reply to a comment by : AA4PB on 2007-02-22

at resonance the antenna is inducing more power into the atmosphere ---------------------------------------------------- Can you point us to a definitive text that proves this, or even claims it to be true?
Reply to a comment by : K9IUQ on 2007-02-22

One TRUE statement was made, a RESONATE antenna will work BETTER than a NON_RESONATE antenna. People do NOT understand resonance ..................................................... The above is an false statement. An Antenna is resonant at ONLY ONE frequency. At any other frequency it is non-resonant. We all use non-resonant antennas (including you) on a daily basis. We make the antenna SYSTEM resonant with a tuner of one kind or another or live with SWR higher than 1:1. Agreed - the whole SYSTEM must be resonance -from the radio to the antenna. It makes little difference if the antenna itself is resonance or not.Many of the best performing wire antennas are non-resonant fed with open wire feeders and an antenna tuner. Also resonance of the SYSTEM has nothing to do with how well the antenna radiates. This is determined by MANY other factors. I have a wonderful Dummy load antenna under my desk that is resonant on all HF bands, however it doesnt seem to radiate very well since I haven't worked too many people with it. Please Pick Up an antenna Book like "Reflections" and learn the facts instead of trying to sell me 'some wonderful ocean front property in Arizona " K9IUQ
N3OX2007-02-22
RE: No Myth
W4LGH:

The excerpt you quoted from that page explains that a center fed antenna has the lowest possible impedance when it's half-wave resonant (or three-halves or five halves, whatever); that is, if you fix the ***voltage*** you feed to an antenna, you'll get the most current, and therefore the biggest field, when it's an odd multiple of a half wave.

If you force the same current in a similar, but nonresonant antenna, you get the same strength field (up to the antenna being a little bit shorter or longer which affects its gain in a minor fashion).

If you had a magical transistor or tube that didn't care if the voltage was not in phase with the current and didn't care how high that voltage got, you would never have to match to a nonresonant antenna.

We always say that we're "transforming the antenna impedance" with a network, but we could equally say "we're transforming the transmitter output up to a voltage with the proper phase to drive the a particular current into the antenna impedance"

An article I found that's more precise:

http://www.cv.nrao.edu/course/astr534/AntennaTheory.html

There's a bunch of stuff later on that isn't particularly applicable to our current discussion, like the impedance of a black hole, but they do talk about reciprocity later on in the page.

73,
Dan






Reply to a comment by : W6TH on 2007-02-22

. W4LGH We have been talking about transmitting antennas, I would like to know a specific purpose for using a non-resonant antenna on a transmitter. ..................................................... A long-wire antenna radiates more power in its most favorable direction than does a half wave resonant antenna in its most favorable direction. This power gain is secured at the expense of radiation in other directions. Would you like me to run some analytical Geometry for you? Maybe my math can convince you. Better yet, lets see what your math can do for me. 73, W6TH .:
Reply to a comment by : W4LGH on 2007-02-22

W6TH wrote..."This is no myth, but the truth. A resonant antenna and a non resonant antenna are both efficient antennas; non are better than the other, each has its own purpose for use." We have been talking about transmitting antennas, I would like to know a specific purpose for using a non-resonant antenna on a transmitter. If one truely understands resonance, I don't understand how anything can be as efficient as one that is resonant. And it is proven to you everytime you load up a transmitter. I certainly understand that weird things will work, but that doesn't make it so. I worked over 15 countries running 3 watts or less into a 50' wire fed at the end with an MFJ 16010 tuner. But the tuner was at the antenna feed point, matching the antenna impedance to the radio, it worked, and I certainly didn't have extra power to spare, but it would have worked BETTER, had the wire been resonant on the frequency I was using, certainly more efficient, as at resonancde the end of the wire looks like an open circuit, where as off resonance it begins to look like a short. 73 de W4LGH Alan http://www.w4lgh.com
Reply to a comment by : W6TH on 2007-02-22

. This is no myth, but the truth. A resonant antenna and a non resonant antenna are both efficient antennas; non are better than the other, each has its own purpose for use. W6TH .:
Reply to a comment by : WB2WIK on 2007-02-22

Not all solid state rigs reduce output power beginning at VSWR = 1.5. That is ultra conservative. The Ten Tec transceivers for years used a circuit breaker in the power supply to tell the transceiver when to "cut back power" due to high VSWR. They'd shut off! But until the breaker tripped, they'd keep transmitting. My Drake TR-7, by published specification, provides 90% of its full rated output power into a 2:1 VSWR and doesn't "fold back" to 50% (which is still about 75W output power) until VSWR = 5:1. That detail is listed here on the last page of the TR-7 brochure: http://wb4hfn.com/DRAKE/DrakeCatalogsBrochures/Brochure_TR7_04B.htm As such, the TR-7 hardly needs a tuner unless the user intends some pretty serious mismatches. Mine can easily produce 100W output power into a 3:1 mismatch, on any band. Without a tuner. It's largely a matter of "headroom" for the power amplifying devices selected. Margins include current, voltage and heat. One problem with a little rig like the FT-857 is its PA devices are small and its PA heatsink is *very* small, not capable of carrying much heat away from the devices, even with a fan. The TR-7 power amplifier heatsink alone (just the heatsink) is larger than the entire FT-857... WB2WIK/6
Reply to a comment by : K6HWH on 2007-02-22

"Every solidstate radio I have ever owned started shutting down power at a 1.5 swr." What about this? I have a Yaesu 857 that does indeed crank down transmit power if the SWR is the least bit off, ostensibly to prevent damage to the output transistors. If even a SWR of 5 does not diminish appreciable the antenna's ability to radiate, isn't this a mistake? Should I be looking for a way to defeat the 857's cautious approach to SWR?
Reply to a comment by : K3AN on 2007-02-22

This article is evidence that you can't determine the usefulness or accuracy of an article by the number of words. If you want useful, accurate information on antennas, please visit the L.B. Cebik web site www.cebik.com. For the last time, there is nothing magical about resonant antennas.
Reply to a comment by : N3OX on 2007-02-22

Respectfully, W4LGH, I would like to point out that you are the one muddying the waters about a *resonant antenna* and its radiating effectiveness. It is not true that antenna element resonance has anything to do with coupling power into the electromagnetic field around the antenna. The *REAL* part of the antenna impedance has two components, the radiation resistance and the loss resistance. That fraction of the power which is associated with "dissipation" in the radiation resistance is the power that gets radiated. The fraction associated with dissipation in the loss resistance goes up as heat. The power in the reactive part of the impedance is simply stored in fields around the antenna. That means that an antenna with an impedance of 70+j0 and one with an impedance of 70+j500 are radiating exactly the same amount of power if you can feed that power to them in the first place. You need to match the antenna system to the transmitter but resonance of the antenna element itself has nothing at all to do with the transfer of that power to radiating electromagnetic fields. If you are supplying 100W to the antenna, 100W minus the antenna losses is radiated, no matter whether or not the antenna element is resonant. 73, Dan
Reply to a comment by : W4LGH on 2007-02-22

You see, here we go again, a good article is written, it contains some great info. Some additional articles are written taken it a little further. Then come the people who truely do not understand what is being said, and either go on what they have seen, or what somebody else who truely doesn't understand told them. ==================================================== Now... AA4PB writes..."at resonance the antenna is inducing more power into the atmosphere ---------------------------------------------------- Can you point us to a definitive text that proves this, or even claims it to be true?" ==================================================== Now with a call like this, this guy is at least an "ADVANCED" class if not an "EXTRA" class, what I said is basic "Physics 101" Resonance is a common thread which runs through almost every branch of physics, and yet a lot of people have never studied it. Without resonance we wouldn't have radio, television, music, or swings on playgrounds, not to mention cool gismos like Tesla coils. Of course, resonance also has its dark side. It occasionally causes a bridge to collapse, a helicopter to fly apart, or other inconveniences. Unlike black holes, time travel, and quantum mechanics, resonance is common place and easy to observe. Yet, it is one of the most striking and unexpected phenomenon in all of physics. It is relative to everything. Here is a good link to read about it...hopefully it will explain.. http://www.intuitor.com/resonance/circuits.html Ever heard the term, "Dip the Plate" when tuning? Notice how the plate current drops but your output increases? Wonder why that is? Could it be your tank circuit has been tuned to resonance? Hmmm...your antenna is an extension of your tank circuit. And to K9IUQ...who wrote..."Also resonance of the SYSTEM has nothing to do with how well the antenna radiates. This is determined by MANY other factors. I have a wonderful Dummy load antenna under my desk that is resonant on all HF bands, however it doesnt seem to radiate very well since I haven't worked too many people with it."... I give up here, this guy just isn't with the program...A dummy LOAD is NOT resonate, it is a resistive LOAD designed to burn up the power by turning it into HEAT! Thats why they call it a dummy LOAD! (key word there is LOAD) Man..you guys say you want elmers, if you truely do not understand something, thats ok, there are people who do understand, and more than willing to help. 73 de W4LGH Alan http://www.w4lgh.com
Reply to a comment by : AA4PB on 2007-02-22

at resonance the antenna is inducing more power into the atmosphere ---------------------------------------------------- Can you point us to a definitive text that proves this, or even claims it to be true?
Reply to a comment by : K9IUQ on 2007-02-22

One TRUE statement was made, a RESONATE antenna will work BETTER than a NON_RESONATE antenna. People do NOT understand resonance ..................................................... The above is an false statement. An Antenna is resonant at ONLY ONE frequency. At any other frequency it is non-resonant. We all use non-resonant antennas (including you) on a daily basis. We make the antenna SYSTEM resonant with a tuner of one kind or another or live with SWR higher than 1:1. Agreed - the whole SYSTEM must be resonance -from the radio to the antenna. It makes little difference if the antenna itself is resonance or not.Many of the best performing wire antennas are non-resonant fed with open wire feeders and an antenna tuner. Also resonance of the SYSTEM has nothing to do with how well the antenna radiates. This is determined by MANY other factors. I have a wonderful Dummy load antenna under my desk that is resonant on all HF bands, however it doesnt seem to radiate very well since I haven't worked too many people with it. Please Pick Up an antenna Book like "Reflections" and learn the facts instead of trying to sell me 'some wonderful ocean front property in Arizona " K9IUQ
W6TH2007-02-22
RE: No Myth
.
W4LGH

We have been talking about transmitting antennas, I would like to know a specific purpose for using a non-resonant antenna on a transmitter.
.....................................................

A long-wire antenna radiates more power in its most favorable direction than does a half wave resonant antenna in its most favorable direction. This power gain is secured at the expense of radiation in other directions.

Would you like me to run some analytical Geometry for you? Maybe my math can convince you.

Better yet, lets see what your math can do for me.

73,

W6TH

.:
Reply to a comment by : W4LGH on 2007-02-22

W6TH wrote..."This is no myth, but the truth. A resonant antenna and a non resonant antenna are both efficient antennas; non are better than the other, each has its own purpose for use." We have been talking about transmitting antennas, I would like to know a specific purpose for using a non-resonant antenna on a transmitter. If one truely understands resonance, I don't understand how anything can be as efficient as one that is resonant. And it is proven to you everytime you load up a transmitter. I certainly understand that weird things will work, but that doesn't make it so. I worked over 15 countries running 3 watts or less into a 50' wire fed at the end with an MFJ 16010 tuner. But the tuner was at the antenna feed point, matching the antenna impedance to the radio, it worked, and I certainly didn't have extra power to spare, but it would have worked BETTER, had the wire been resonant on the frequency I was using, certainly more efficient, as at resonancde the end of the wire looks like an open circuit, where as off resonance it begins to look like a short. 73 de W4LGH Alan http://www.w4lgh.com
Reply to a comment by : W6TH on 2007-02-22

. This is no myth, but the truth. A resonant antenna and a non resonant antenna are both efficient antennas; non are better than the other, each has its own purpose for use. W6TH .:
Reply to a comment by : WB2WIK on 2007-02-22

Not all solid state rigs reduce output power beginning at VSWR = 1.5. That is ultra conservative. The Ten Tec transceivers for years used a circuit breaker in the power supply to tell the transceiver when to "cut back power" due to high VSWR. They'd shut off! But until the breaker tripped, they'd keep transmitting. My Drake TR-7, by published specification, provides 90% of its full rated output power into a 2:1 VSWR and doesn't "fold back" to 50% (which is still about 75W output power) until VSWR = 5:1. That detail is listed here on the last page of the TR-7 brochure: http://wb4hfn.com/DRAKE/DrakeCatalogsBrochures/Brochure_TR7_04B.htm As such, the TR-7 hardly needs a tuner unless the user intends some pretty serious mismatches. Mine can easily produce 100W output power into a 3:1 mismatch, on any band. Without a tuner. It's largely a matter of "headroom" for the power amplifying devices selected. Margins include current, voltage and heat. One problem with a little rig like the FT-857 is its PA devices are small and its PA heatsink is *very* small, not capable of carrying much heat away from the devices, even with a fan. The TR-7 power amplifier heatsink alone (just the heatsink) is larger than the entire FT-857... WB2WIK/6
Reply to a comment by : K6HWH on 2007-02-22

"Every solidstate radio I have ever owned started shutting down power at a 1.5 swr." What about this? I have a Yaesu 857 that does indeed crank down transmit power if the SWR is the least bit off, ostensibly to prevent damage to the output transistors. If even a SWR of 5 does not diminish appreciable the antenna's ability to radiate, isn't this a mistake? Should I be looking for a way to defeat the 857's cautious approach to SWR?
Reply to a comment by : K3AN on 2007-02-22

This article is evidence that you can't determine the usefulness or accuracy of an article by the number of words. If you want useful, accurate information on antennas, please visit the L.B. Cebik web site www.cebik.com. For the last time, there is nothing magical about resonant antennas.
Reply to a comment by : N3OX on 2007-02-22

Respectfully, W4LGH, I would like to point out that you are the one muddying the waters about a *resonant antenna* and its radiating effectiveness. It is not true that antenna element resonance has anything to do with coupling power into the electromagnetic field around the antenna. The *REAL* part of the antenna impedance has two components, the radiation resistance and the loss resistance. That fraction of the power which is associated with "dissipation" in the radiation resistance is the power that gets radiated. The fraction associated with dissipation in the loss resistance goes up as heat. The power in the reactive part of the impedance is simply stored in fields around the antenna. That means that an antenna with an impedance of 70+j0 and one with an impedance of 70+j500 are radiating exactly the same amount of power if you can feed that power to them in the first place. You need to match the antenna system to the transmitter but resonance of the antenna element itself has nothing at all to do with the transfer of that power to radiating electromagnetic fields. If you are supplying 100W to the antenna, 100W minus the antenna losses is radiated, no matter whether or not the antenna element is resonant. 73, Dan
Reply to a comment by : W4LGH on 2007-02-22

You see, here we go again, a good article is written, it contains some great info. Some additional articles are written taken it a little further. Then come the people who truely do not understand what is being said, and either go on what they have seen, or what somebody else who truely doesn't understand told them. ==================================================== Now... AA4PB writes..."at resonance the antenna is inducing more power into the atmosphere ---------------------------------------------------- Can you point us to a definitive text that proves this, or even claims it to be true?" ==================================================== Now with a call like this, this guy is at least an "ADVANCED" class if not an "EXTRA" class, what I said is basic "Physics 101" Resonance is a common thread which runs through almost every branch of physics, and yet a lot of people have never studied it. Without resonance we wouldn't have radio, television, music, or swings on playgrounds, not to mention cool gismos like Tesla coils. Of course, resonance also has its dark side. It occasionally causes a bridge to collapse, a helicopter to fly apart, or other inconveniences. Unlike black holes, time travel, and quantum mechanics, resonance is common place and easy to observe. Yet, it is one of the most striking and unexpected phenomenon in all of physics. It is relative to everything. Here is a good link to read about it...hopefully it will explain.. http://www.intuitor.com/resonance/circuits.html Ever heard the term, "Dip the Plate" when tuning? Notice how the plate current drops but your output increases? Wonder why that is? Could it be your tank circuit has been tuned to resonance? Hmmm...your antenna is an extension of your tank circuit. And to K9IUQ...who wrote..."Also resonance of the SYSTEM has nothing to do with how well the antenna radiates. This is determined by MANY other factors. I have a wonderful Dummy load antenna under my desk that is resonant on all HF bands, however it doesnt seem to radiate very well since I haven't worked too many people with it."... I give up here, this guy just isn't with the program...A dummy LOAD is NOT resonate, it is a resistive LOAD designed to burn up the power by turning it into HEAT! Thats why they call it a dummy LOAD! (key word there is LOAD) Man..you guys say you want elmers, if you truely do not understand something, thats ok, there are people who do understand, and more than willing to help. 73 de W4LGH Alan http://www.w4lgh.com
Reply to a comment by : AA4PB on 2007-02-22

at resonance the antenna is inducing more power into the atmosphere ---------------------------------------------------- Can you point us to a definitive text that proves this, or even claims it to be true?
Reply to a comment by : K9IUQ on 2007-02-22

One TRUE statement was made, a RESONATE antenna will work BETTER than a NON_RESONATE antenna. People do NOT understand resonance ..................................................... The above is an false statement. An Antenna is resonant at ONLY ONE frequency. At any other frequency it is non-resonant. We all use non-resonant antennas (including you) on a daily basis. We make the antenna SYSTEM resonant with a tuner of one kind or another or live with SWR higher than 1:1. Agreed - the whole SYSTEM must be resonance -from the radio to the antenna. It makes little difference if the antenna itself is resonance or not.Many of the best performing wire antennas are non-resonant fed with open wire feeders and an antenna tuner. Also resonance of the SYSTEM has nothing to do with how well the antenna radiates. This is determined by MANY other factors. I have a wonderful Dummy load antenna under my desk that is resonant on all HF bands, however it doesnt seem to radiate very well since I haven't worked too many people with it. Please Pick Up an antenna Book like "Reflections" and learn the facts instead of trying to sell me 'some wonderful ocean front property in Arizona " K9IUQ
K9IUQ2007-02-22
Benchmarks
W6TH Says

This is no myth, but the truth.

A resonant antenna and a non resonant antenna are both efficient antennas; non are better than the other, each has its own purpose for use.

......................................................

K9IUQ Says
Two simple sentences and you said what I have been trying to say in 10 posts. You must be an oldtimer...
I am awed by the simplicity of what you just said.

........................................................

To W4LGH
You really need to give this thread up, you are starting to be silly.
Please go read Maxwell's Reflections Book, PLEASE....

Better to Be Thought a Fool, than to open your mouth and Prove it.
K9IUQ


N3JBH2007-02-22
RE: No Myth
I Love to See W8JI's input on this. Tom allway's has some thing good to add to antenna comments
Reply to a comment by : W4LGH on 2007-02-22

W6TH wrote..."This is no myth, but the truth. A resonant antenna and a non resonant antenna are both efficient antennas; non are better than the other, each has its own purpose for use." We have been talking about transmitting antennas, I would like to know a specific purpose for using a non-resonant antenna on a transmitter. If one truely understands resonance, I don't understand how anything can be as efficient as one that is resonant. And it is proven to you everytime you load up a transmitter. I certainly understand that weird things will work, but that doesn't make it so. I worked over 15 countries running 3 watts or less into a 50' wire fed at the end with an MFJ 16010 tuner. But the tuner was at the antenna feed point, matching the antenna impedance to the radio, it worked, and I certainly didn't have extra power to spare, but it would have worked BETTER, had the wire been resonant on the frequency I was using, certainly more efficient, as at resonancde the end of the wire looks like an open circuit, where as off resonance it begins to look like a short. 73 de W4LGH Alan http://www.w4lgh.com
Reply to a comment by : W6TH on 2007-02-22

. This is no myth, but the truth. A resonant antenna and a non resonant antenna are both efficient antennas; non are better than the other, each has its own purpose for use. W6TH .:
Reply to a comment by : WB2WIK on 2007-02-22

Not all solid state rigs reduce output power beginning at VSWR = 1.5. That is ultra conservative. The Ten Tec transceivers for years used a circuit breaker in the power supply to tell the transceiver when to "cut back power" due to high VSWR. They'd shut off! But until the breaker tripped, they'd keep transmitting. My Drake TR-7, by published specification, provides 90% of its full rated output power into a 2:1 VSWR and doesn't "fold back" to 50% (which is still about 75W output power) until VSWR = 5:1. That detail is listed here on the last page of the TR-7 brochure: http://wb4hfn.com/DRAKE/DrakeCatalogsBrochures/Brochure_TR7_04B.htm As such, the TR-7 hardly needs a tuner unless the user intends some pretty serious mismatches. Mine can easily produce 100W output power into a 3:1 mismatch, on any band. Without a tuner. It's largely a matter of "headroom" for the power amplifying devices selected. Margins include current, voltage and heat. One problem with a little rig like the FT-857 is its PA devices are small and its PA heatsink is *very* small, not capable of carrying much heat away from the devices, even with a fan. The TR-7 power amplifier heatsink alone (just the heatsink) is larger than the entire FT-857... WB2WIK/6
Reply to a comment by : K6HWH on 2007-02-22

"Every solidstate radio I have ever owned started shutting down power at a 1.5 swr." What about this? I have a Yaesu 857 that does indeed crank down transmit power if the SWR is the least bit off, ostensibly to prevent damage to the output transistors. If even a SWR of 5 does not diminish appreciable the antenna's ability to radiate, isn't this a mistake? Should I be looking for a way to defeat the 857's cautious approach to SWR?
Reply to a comment by : K3AN on 2007-02-22

This article is evidence that you can't determine the usefulness or accuracy of an article by the number of words. If you want useful, accurate information on antennas, please visit the L.B. Cebik web site www.cebik.com. For the last time, there is nothing magical about resonant antennas.
Reply to a comment by : N3OX on 2007-02-22

Respectfully, W4LGH, I would like to point out that you are the one muddying the waters about a *resonant antenna* and its radiating effectiveness. It is not true that antenna element resonance has anything to do with coupling power into the electromagnetic field around the antenna. The *REAL* part of the antenna impedance has two components, the radiation resistance and the loss resistance. That fraction of the power which is associated with "dissipation" in the radiation resistance is the power that gets radiated. The fraction associated with dissipation in the loss resistance goes up as heat. The power in the reactive part of the impedance is simply stored in fields around the antenna. That means that an antenna with an impedance of 70+j0 and one with an impedance of 70+j500 are radiating exactly the same amount of power if you can feed that power to them in the first place. You need to match the antenna system to the transmitter but resonance of the antenna element itself has nothing at all to do with the transfer of that power to radiating electromagnetic fields. If you are supplying 100W to the antenna, 100W minus the antenna losses is radiated, no matter whether or not the antenna element is resonant. 73, Dan
Reply to a comment by : W4LGH on 2007-02-22

You see, here we go again, a good article is written, it contains some great info. Some additional articles are written taken it a little further. Then come the people who truely do not understand what is being said, and either go on what they have seen, or what somebody else who truely doesn't understand told them. ==================================================== Now... AA4PB writes..."at resonance the antenna is inducing more power into the atmosphere ---------------------------------------------------- Can you point us to a definitive text that proves this, or even claims it to be true?" ==================================================== Now with a call like this, this guy is at least an "ADVANCED" class if not an "EXTRA" class, what I said is basic "Physics 101" Resonance is a common thread which runs through almost every branch of physics, and yet a lot of people have never studied it. Without resonance we wouldn't have radio, television, music, or swings on playgrounds, not to mention cool gismos like Tesla coils. Of course, resonance also has its dark side. It occasionally causes a bridge to collapse, a helicopter to fly apart, or other inconveniences. Unlike black holes, time travel, and quantum mechanics, resonance is common place and easy to observe. Yet, it is one of the most striking and unexpected phenomenon in all of physics. It is relative to everything. Here is a good link to read about it...hopefully it will explain.. http://www.intuitor.com/resonance/circuits.html Ever heard the term, "Dip the Plate" when tuning? Notice how the plate current drops but your output increases? Wonder why that is? Could it be your tank circuit has been tuned to resonance? Hmmm...your antenna is an extension of your tank circuit. And to K9IUQ...who wrote..."Also resonance of the SYSTEM has nothing to do with how well the antenna radiates. This is determined by MANY other factors. I have a wonderful Dummy load antenna under my desk that is resonant on all HF bands, however it doesnt seem to radiate very well since I haven't worked too many people with it."... I give up here, this guy just isn't with the program...A dummy LOAD is NOT resonate, it is a resistive LOAD designed to burn up the power by turning it into HEAT! Thats why they call it a dummy LOAD! (key word there is LOAD) Man..you guys say you want elmers, if you truely do not understand something, thats ok, there are people who do understand, and more than willing to help. 73 de W4LGH Alan http://www.w4lgh.com
Reply to a comment by : AA4PB on 2007-02-22

at resonance the antenna is inducing more power into the atmosphere ---------------------------------------------------- Can you point us to a definitive text that proves this, or even claims it to be true?
Reply to a comment by : K9IUQ on 2007-02-22

One TRUE statement was made, a RESONATE antenna will work BETTER than a NON_RESONATE antenna. People do NOT understand resonance ..................................................... The above is an false statement. An Antenna is resonant at ONLY ONE frequency. At any other frequency it is non-resonant. We all use non-resonant antennas (including you) on a daily basis. We make the antenna SYSTEM resonant with a tuner of one kind or another or live with SWR higher than 1:1. Agreed - the whole SYSTEM must be resonance -from the radio to the antenna. It makes little difference if the antenna itself is resonance or not.Many of the best performing wire antennas are non-resonant fed with open wire feeders and an antenna tuner. Also resonance of the SYSTEM has nothing to do with how well the antenna radiates. This is determined by MANY other factors. I have a wonderful Dummy load antenna under my desk that is resonant on all HF bands, however it doesnt seem to radiate very well since I haven't worked too many people with it. Please Pick Up an antenna Book like "Reflections" and learn the facts instead of trying to sell me 'some wonderful ocean front property in Arizona " K9IUQ
W4LGH2007-02-22
RE: No Myth
W6TH wrote..."This is no myth, but the truth.
A resonant antenna and a non resonant antenna are both efficient antennas; non are better than the other, each has its own purpose for use."

We have been talking about transmitting antennas, I would like to know a specific purpose for using a non-resonant antenna on a transmitter.

If one truely understands resonance, I don't understand how anything can be as efficient as one that is resonant. And it is proven to you everytime you load up a transmitter.

I certainly understand that weird things will work, but that doesn't make it so. I worked over 15 countries running 3 watts or less into a 50' wire fed at the end with an MFJ 16010 tuner. But the tuner was at the antenna feed point, matching the antenna impedance to the radio, it worked, and I certainly didn't have extra power to spare, but it would have worked BETTER, had the wire been resonant on the frequency I was using, certainly more efficient, as at resonancde the end of the wire looks like an open circuit, where as off resonance it begins to look like a short.

73 de W4LGH Alan
http://www.w4lgh.com

Reply to a comment by : W6TH on 2007-02-22

. This is no myth, but the truth. A resonant antenna and a non resonant antenna are both efficient antennas; non are better than the other, each has its own purpose for use. W6TH .:
Reply to a comment by : WB2WIK on 2007-02-22

Not all solid state rigs reduce output power beginning at VSWR = 1.5. That is ultra conservative. The Ten Tec transceivers for years used a circuit breaker in the power supply to tell the transceiver when to "cut back power" due to high VSWR. They'd shut off! But until the breaker tripped, they'd keep transmitting. My Drake TR-7, by published specification, provides 90% of its full rated output power into a 2:1 VSWR and doesn't "fold back" to 50% (which is still about 75W output power) until VSWR = 5:1. That detail is listed here on the last page of the TR-7 brochure: http://wb4hfn.com/DRAKE/DrakeCatalogsBrochures/Brochure_TR7_04B.htm As such, the TR-7 hardly needs a tuner unless the user intends some pretty serious mismatches. Mine can easily produce 100W output power into a 3:1 mismatch, on any band. Without a tuner. It's largely a matter of "headroom" for the power amplifying devices selected. Margins include current, voltage and heat. One problem with a little rig like the FT-857 is its PA devices are small and its PA heatsink is *very* small, not capable of carrying much heat away from the devices, even with a fan. The TR-7 power amplifier heatsink alone (just the heatsink) is larger than the entire FT-857... WB2WIK/6
Reply to a comment by : K6HWH on 2007-02-22

"Every solidstate radio I have ever owned started shutting down power at a 1.5 swr." What about this? I have a Yaesu 857 that does indeed crank down transmit power if the SWR is the least bit off, ostensibly to prevent damage to the output transistors. If even a SWR of 5 does not diminish appreciable the antenna's ability to radiate, isn't this a mistake? Should I be looking for a way to defeat the 857's cautious approach to SWR?
Reply to a comment by : K3AN on 2007-02-22

This article is evidence that you can't determine the usefulness or accuracy of an article by the number of words. If you want useful, accurate information on antennas, please visit the L.B. Cebik web site www.cebik.com. For the last time, there is nothing magical about resonant antennas.
Reply to a comment by : N3OX on 2007-02-22

Respectfully, W4LGH, I would like to point out that you are the one muddying the waters about a *resonant antenna* and its radiating effectiveness. It is not true that antenna element resonance has anything to do with coupling power into the electromagnetic field around the antenna. The *REAL* part of the antenna impedance has two components, the radiation resistance and the loss resistance. That fraction of the power which is associated with "dissipation" in the radiation resistance is the power that gets radiated. The fraction associated with dissipation in the loss resistance goes up as heat. The power in the reactive part of the impedance is simply stored in fields around the antenna. That means that an antenna with an impedance of 70+j0 and one with an impedance of 70+j500 are radiating exactly the same amount of power if you can feed that power to them in the first place. You need to match the antenna system to the transmitter but resonance of the antenna element itself has nothing at all to do with the transfer of that power to radiating electromagnetic fields. If you are supplying 100W to the antenna, 100W minus the antenna losses is radiated, no matter whether or not the antenna element is resonant. 73, Dan
Reply to a comment by : W4LGH on 2007-02-22

You see, here we go again, a good article is written, it contains some great info. Some additional articles are written taken it a little further. Then come the people who truely do not understand what is being said, and either go on what they have seen, or what somebody else who truely doesn't understand told them. ==================================================== Now... AA4PB writes..."at resonance the antenna is inducing more power into the atmosphere ---------------------------------------------------- Can you point us to a definitive text that proves this, or even claims it to be true?" ==================================================== Now with a call like this, this guy is at least an "ADVANCED" class if not an "EXTRA" class, what I said is basic "Physics 101" Resonance is a common thread which runs through almost every branch of physics, and yet a lot of people have never studied it. Without resonance we wouldn't have radio, television, music, or swings on playgrounds, not to mention cool gismos like Tesla coils. Of course, resonance also has its dark side. It occasionally causes a bridge to collapse, a helicopter to fly apart, or other inconveniences. Unlike black holes, time travel, and quantum mechanics, resonance is common place and easy to observe. Yet, it is one of the most striking and unexpected phenomenon in all of physics. It is relative to everything. Here is a good link to read about it...hopefully it will explain.. http://www.intuitor.com/resonance/circuits.html Ever heard the term, "Dip the Plate" when tuning? Notice how the plate current drops but your output increases? Wonder why that is? Could it be your tank circuit has been tuned to resonance? Hmmm...your antenna is an extension of your tank circuit. And to K9IUQ...who wrote..."Also resonance of the SYSTEM has nothing to do with how well the antenna radiates. This is determined by MANY other factors. I have a wonderful Dummy load antenna under my desk that is resonant on all HF bands, however it doesnt seem to radiate very well since I haven't worked too many people with it."... I give up here, this guy just isn't with the program...A dummy LOAD is NOT resonate, it is a resistive LOAD designed to burn up the power by turning it into HEAT! Thats why they call it a dummy LOAD! (key word there is LOAD) Man..you guys say you want elmers, if you truely do not understand something, thats ok, there are people who do understand, and more than willing to help. 73 de W4LGH Alan http://www.w4lgh.com
Reply to a comment by : AA4PB on 2007-02-22

at resonance the antenna is inducing more power into the atmosphere ---------------------------------------------------- Can you point us to a definitive text that proves this, or even claims it to be true?
Reply to a comment by : K9IUQ on 2007-02-22

One TRUE statement was made, a RESONATE antenna will work BETTER than a NON_RESONATE antenna. People do NOT understand resonance ..................................................... The above is an false statement. An Antenna is resonant at ONLY ONE frequency. At any other frequency it is non-resonant. We all use non-resonant antennas (including you) on a daily basis. We make the antenna SYSTEM resonant with a tuner of one kind or another or live with SWR higher than 1:1. Agreed - the whole SYSTEM must be resonance -from the radio to the antenna. It makes little difference if the antenna itself is resonance or not.Many of the best performing wire antennas are non-resonant fed with open wire feeders and an antenna tuner. Also resonance of the SYSTEM has nothing to do with how well the antenna radiates. This is determined by MANY other factors. I have a wonderful Dummy load antenna under my desk that is resonant on all HF bands, however it doesnt seem to radiate very well since I haven't worked too many people with it. Please Pick Up an antenna Book like "Reflections" and learn the facts instead of trying to sell me 'some wonderful ocean front property in Arizona " K9IUQ
N4KC2007-02-22
RE: No Myth
And I'll add to W6TH's very succinct...and highly accurate...statement with just one thought. We should not be talking about antennas, tuners, baluns, feedlines, etc. as separate entities.

We should be talking about antenna "systems." And that consists of everything from the output stage of your final amplifier, including output circuit of the rig, tuner, feedline, feedpoint, objects adjacent to the feedline and antenna, the ground beneath it, that pretty fir tree that almost touches the 75-meter dipole, your neighbor's chainlink fence, and the mountain filled with iron ore five miles to the north. There are many, many factors that effect SWR, load, radiation resistance, pattern, angle of radiation, and more...many of which we have absolutely no control over. And that doesn't even take into consideration the neighborhood homeowners' association or the XYL.

Let's learn all we can, make the sacrifices and compromises that we must to get the best SYSTEM we can and enjoy. Meanwhile, learn, experiment, try (and make mistakes), and if one antenna works better than the first, take the first one down and use the second. Oh, and try to have at least two choices for every band. There are many times when a simple dipole works better than an exotic beam. Not many, but I sure would prefer to have the option!

73,

Don N4KC
www.donkeith.com

PS: This has STILL been a very informative discussion. Let's continue it on the air tonight somewhere!
Reply to a comment by : W6TH on 2007-02-22

. This is no myth, but the truth. A resonant antenna and a non resonant antenna are both efficient antennas; non are better than the other, each has its own purpose for use. W6TH .:
Reply to a comment by : WB2WIK on 2007-02-22

Not all solid state rigs reduce output power beginning at VSWR = 1.5. That is ultra conservative. The Ten Tec transceivers for years used a circuit breaker in the power supply to tell the transceiver when to "cut back power" due to high VSWR. They'd shut off! But until the breaker tripped, they'd keep transmitting. My Drake TR-7, by published specification, provides 90% of its full rated output power into a 2:1 VSWR and doesn't "fold back" to 50% (which is still about 75W output power) until VSWR = 5:1. That detail is listed here on the last page of the TR-7 brochure: http://wb4hfn.com/DRAKE/DrakeCatalogsBrochures/Brochure_TR7_04B.htm As such, the TR-7 hardly needs a tuner unless the user intends some pretty serious mismatches. Mine can easily produce 100W output power into a 3:1 mismatch, on any band. Without a tuner. It's largely a matter of "headroom" for the power amplifying devices selected. Margins include current, voltage and heat. One problem with a little rig like the FT-857 is its PA devices are small and its PA heatsink is *very* small, not capable of carrying much heat away from the devices, even with a fan. The TR-7 power amplifier heatsink alone (just the heatsink) is larger than the entire FT-857... WB2WIK/6
Reply to a comment by : K6HWH on 2007-02-22

"Every solidstate radio I have ever owned started shutting down power at a 1.5 swr." What about this? I have a Yaesu 857 that does indeed crank down transmit power if the SWR is the least bit off, ostensibly to prevent damage to the output transistors. If even a SWR of 5 does not diminish appreciable the antenna's ability to radiate, isn't this a mistake? Should I be looking for a way to defeat the 857's cautious approach to SWR?
Reply to a comment by : K3AN on 2007-02-22

This article is evidence that you can't determine the usefulness or accuracy of an article by the number of words. If you want useful, accurate information on antennas, please visit the L.B. Cebik web site www.cebik.com. For the last time, there is nothing magical about resonant antennas.
Reply to a comment by : N3OX on 2007-02-22

Respectfully, W4LGH, I would like to point out that you are the one muddying the waters about a *resonant antenna* and its radiating effectiveness. It is not true that antenna element resonance has anything to do with coupling power into the electromagnetic field around the antenna. The *REAL* part of the antenna impedance has two components, the radiation resistance and the loss resistance. That fraction of the power which is associated with "dissipation" in the radiation resistance is the power that gets radiated. The fraction associated with dissipation in the loss resistance goes up as heat. The power in the reactive part of the impedance is simply stored in fields around the antenna. That means that an antenna with an impedance of 70+j0 and one with an impedance of 70+j500 are radiating exactly the same amount of power if you can feed that power to them in the first place. You need to match the antenna system to the transmitter but resonance of the antenna element itself has nothing at all to do with the transfer of that power to radiating electromagnetic fields. If you are supplying 100W to the antenna, 100W minus the antenna losses is radiated, no matter whether or not the antenna element is resonant. 73, Dan
Reply to a comment by : W4LGH on 2007-02-22

You see, here we go again, a good article is written, it contains some great info. Some additional articles are written taken it a little further. Then come the people who truely do not understand what is being said, and either go on what they have seen, or what somebody else who truely doesn't understand told them. ==================================================== Now... AA4PB writes..."at resonance the antenna is inducing more power into the atmosphere ---------------------------------------------------- Can you point us to a definitive text that proves this, or even claims it to be true?" ==================================================== Now with a call like this, this guy is at least an "ADVANCED" class if not an "EXTRA" class, what I said is basic "Physics 101" Resonance is a common thread which runs through almost every branch of physics, and yet a lot of people have never studied it. Without resonance we wouldn't have radio, television, music, or swings on playgrounds, not to mention cool gismos like Tesla coils. Of course, resonance also has its dark side. It occasionally causes a bridge to collapse, a helicopter to fly apart, or other inconveniences. Unlike black holes, time travel, and quantum mechanics, resonance is common place and easy to observe. Yet, it is one of the most striking and unexpected phenomenon in all of physics. It is relative to everything. Here is a good link to read about it...hopefully it will explain.. http://www.intuitor.com/resonance/circuits.html Ever heard the term, "Dip the Plate" when tuning? Notice how the plate current drops but your output increases? Wonder why that is? Could it be your tank circuit has been tuned to resonance? Hmmm...your antenna is an extension of your tank circuit. And to K9IUQ...who wrote..."Also resonance of the SYSTEM has nothing to do with how well the antenna radiates. This is determined by MANY other factors. I have a wonderful Dummy load antenna under my desk that is resonant on all HF bands, however it doesnt seem to radiate very well since I haven't worked too many people with it."... I give up here, this guy just isn't with the program...A dummy LOAD is NOT resonate, it is a resistive LOAD designed to burn up the power by turning it into HEAT! Thats why they call it a dummy LOAD! (key word there is LOAD) Man..you guys say you want elmers, if you truely do not understand something, thats ok, there are people who do understand, and more than willing to help. 73 de W4LGH Alan http://www.w4lgh.com
Reply to a comment by : AA4PB on 2007-02-22

at resonance the antenna is inducing more power into the atmosphere ---------------------------------------------------- Can you point us to a definitive text that proves this, or even claims it to be true?
Reply to a comment by : K9IUQ on 2007-02-22

One TRUE statement was made, a RESONATE antenna will work BETTER than a NON_RESONATE antenna. People do NOT understand resonance ..................................................... The above is an false statement. An Antenna is resonant at ONLY ONE frequency. At any other frequency it is non-resonant. We all use non-resonant antennas (including you) on a daily basis. We make the antenna SYSTEM resonant with a tuner of one kind or another or live with SWR higher than 1:1. Agreed - the whole SYSTEM must be resonance -from the radio to the antenna. It makes little difference if the antenna itself is resonance or not.Many of the best performing wire antennas are non-resonant fed with open wire feeders and an antenna tuner. Also resonance of the SYSTEM has nothing to do with how well the antenna radiates. This is determined by MANY other factors. I have a wonderful Dummy load antenna under my desk that is resonant on all HF bands, however it doesnt seem to radiate very well since I haven't worked too many people with it. Please Pick Up an antenna Book like "Reflections" and learn the facts instead of trying to sell me 'some wonderful ocean front property in Arizona " K9IUQ
KB1MQR2007-02-22
Benchmarks
This artical was a real teaser. Much of the subjective statement I tend to agree with. What I would really like is a good quantative analysis and measurement of the losses from a common transciever, thru a populat tuner, via standard coza to a popular antenna. This one case would provide real insight on effeciency, SWR and the benefits and loses normally over look.

After we have these quanitative facts, some suggestions for improvement would be greatly appreciated
W6TH2007-02-22
RE: No Myth
.
This is no myth, but the truth.

A resonant antenna and a non resonant antenna are both efficient antennas; non are better than the other, each has its own purpose for use.

W6TH
.:
Reply to a comment by : WB2WIK on 2007-02-22

Not all solid state rigs reduce output power beginning at VSWR = 1.5. That is ultra conservative. The Ten Tec transceivers for years used a circuit breaker in the power supply to tell the transceiver when to "cut back power" due to high VSWR. They'd shut off! But until the breaker tripped, they'd keep transmitting. My Drake TR-7, by published specification, provides 90% of its full rated output power into a 2:1 VSWR and doesn't "fold back" to 50% (which is still about 75W output power) until VSWR = 5:1. That detail is listed here on the last page of the TR-7 brochure: http://wb4hfn.com/DRAKE/DrakeCatalogsBrochures/Brochure_TR7_04B.htm As such, the TR-7 hardly needs a tuner unless the user intends some pretty serious mismatches. Mine can easily produce 100W output power into a 3:1 mismatch, on any band. Without a tuner. It's largely a matter of "headroom" for the power amplifying devices selected. Margins include current, voltage and heat. One problem with a little rig like the FT-857 is its PA devices are small and its PA heatsink is *very* small, not capable of carrying much heat away from the devices, even with a fan. The TR-7 power amplifier heatsink alone (just the heatsink) is larger than the entire FT-857... WB2WIK/6
Reply to a comment by : K6HWH on 2007-02-22

"Every solidstate radio I have ever owned started shutting down power at a 1.5 swr." What about this? I have a Yaesu 857 that does indeed crank down transmit power if the SWR is the least bit off, ostensibly to prevent damage to the output transistors. If even a SWR of 5 does not diminish appreciable the antenna's ability to radiate, isn't this a mistake? Should I be looking for a way to defeat the 857's cautious approach to SWR?
Reply to a comment by : K3AN on 2007-02-22

This article is evidence that you can't determine the usefulness or accuracy of an article by the number of words. If you want useful, accurate information on antennas, please visit the L.B. Cebik web site www.cebik.com. For the last time, there is nothing magical about resonant antennas.
Reply to a comment by : N3OX on 2007-02-22

Respectfully, W4LGH, I would like to point out that you are the one muddying the waters about a *resonant antenna* and its radiating effectiveness. It is not true that antenna element resonance has anything to do with coupling power into the electromagnetic field around the antenna. The *REAL* part of the antenna impedance has two components, the radiation resistance and the loss resistance. That fraction of the power which is associated with "dissipation" in the radiation resistance is the power that gets radiated. The fraction associated with dissipation in the loss resistance goes up as heat. The power in the reactive part of the impedance is simply stored in fields around the antenna. That means that an antenna with an impedance of 70+j0 and one with an impedance of 70+j500 are radiating exactly the same amount of power if you can feed that power to them in the first place. You need to match the antenna system to the transmitter but resonance of the antenna element itself has nothing at all to do with the transfer of that power to radiating electromagnetic fields. If you are supplying 100W to the antenna, 100W minus the antenna losses is radiated, no matter whether or not the antenna element is resonant. 73, Dan
Reply to a comment by : W4LGH on 2007-02-22

You see, here we go again, a good article is written, it contains some great info. Some additional articles are written taken it a little further. Then come the people who truely do not understand what is being said, and either go on what they have seen, or what somebody else who truely doesn't understand told them. ==================================================== Now... AA4PB writes..."at resonance the antenna is inducing more power into the atmosphere ---------------------------------------------------- Can you point us to a definitive text that proves this, or even claims it to be true?" ==================================================== Now with a call like this, this guy is at least an "ADVANCED" class if not an "EXTRA" class, what I said is basic "Physics 101" Resonance is a common thread which runs through almost every branch of physics, and yet a lot of people have never studied it. Without resonance we wouldn't have radio, television, music, or swings on playgrounds, not to mention cool gismos like Tesla coils. Of course, resonance also has its dark side. It occasionally causes a bridge to collapse, a helicopter to fly apart, or other inconveniences. Unlike black holes, time travel, and quantum mechanics, resonance is common place and easy to observe. Yet, it is one of the most striking and unexpected phenomenon in all of physics. It is relative to everything. Here is a good link to read about it...hopefully it will explain.. http://www.intuitor.com/resonance/circuits.html Ever heard the term, "Dip the Plate" when tuning? Notice how the plate current drops but your output increases? Wonder why that is? Could it be your tank circuit has been tuned to resonance? Hmmm...your antenna is an extension of your tank circuit. And to K9IUQ...who wrote..."Also resonance of the SYSTEM has nothing to do with how well the antenna radiates. This is determined by MANY other factors. I have a wonderful Dummy load antenna under my desk that is resonant on all HF bands, however it doesnt seem to radiate very well since I haven't worked too many people with it."... I give up here, this guy just isn't with the program...A dummy LOAD is NOT resonate, it is a resistive LOAD designed to burn up the power by turning it into HEAT! Thats why they call it a dummy LOAD! (key word there is LOAD) Man..you guys say you want elmers, if you truely do not understand something, thats ok, there are people who do understand, and more than willing to help. 73 de W4LGH Alan http://www.w4lgh.com
Reply to a comment by : AA4PB on 2007-02-22

at resonance the antenna is inducing more power into the atmosphere ---------------------------------------------------- Can you point us to a definitive text that proves this, or even claims it to be true?
Reply to a comment by : K9IUQ on 2007-02-22

One TRUE statement was made, a RESONATE antenna will work BETTER than a NON_RESONATE antenna. People do NOT understand resonance ..................................................... The above is an false statement. An Antenna is resonant at ONLY ONE frequency. At any other frequency it is non-resonant. We all use non-resonant antennas (including you) on a daily basis. We make the antenna SYSTEM resonant with a tuner of one kind or another or live with SWR higher than 1:1. Agreed - the whole SYSTEM must be resonance -from the radio to the antenna. It makes little difference if the antenna itself is resonance or not.Many of the best performing wire antennas are non-resonant fed with open wire feeders and an antenna tuner. Also resonance of the SYSTEM has nothing to do with how well the antenna radiates. This is determined by MANY other factors. I have a wonderful Dummy load antenna under my desk that is resonant on all HF bands, however it doesnt seem to radiate very well since I haven't worked too many people with it. Please Pick Up an antenna Book like "Reflections" and learn the facts instead of trying to sell me 'some wonderful ocean front property in Arizona " K9IUQ
WB2WIK2007-02-22
RE: Benchmarks
?Benchmarks Reply
by G0GQK on February 22, 2007 Mail this to a friend!
What is THE benchmark ? Who has the efficient antenna locally to make a comparison, which is over the same kind of ground, at the same height, and lined up in the same way ?<

::Mel, it needn't be. The benchmark needn't be a 1/2 wave dipole, either. It's another antenna in a closeby location, used to contact the same distant station on the same frequency at the same time. Two or three or six or eight "other" antennas also in closeby locations used to contact the same distant station on the same frequency at the same time is even better. It doesn't matter if the benchmark has 0.00 dBd gain, or what it has. It's just another antenna used for comparison with the one being evaluated.

::Perfect example: Lately, about four days a week my friend and neighbor Dave WA6DKN, who lives very close to me, and I have been operating 40 meters at the same time. Me, from my home and Dave from his. We both run a kilowatt output and we're close enough together to be considered the "same location" to any station we contact via ionospheric propagation. In about nine out of ten contacts made with anybody, anywhere, I get better reports. Sometimes 1 S unit better, sometimes 2 S units, sometimes less, sometimes more. Just "stronger." I don't trust S meters, but when you get nine out of ten stations telling you that you have an obviously stronger signal, the trend is obvious. We're both running the same power from effectively the same location (same earth resistivity, etc). The reporting stations can be 100 miles away, 1000 miles away, 3000 miles away...it doesn't seem to matter.

::The only logical conclusion is that my antenna is more effective than Dave's is, for this band. Now, we are scientifically trying to verify "why." This isn't so easy.

::Dave's using a Butternut HF2V which on 40m is a full-sized, 1/4-wavelength base-fed vertical, over a field of about 50 radials. It should be pretty good. It models to have about the same TOA as my antenna, which is a 1/2-wave inverted vee (wire) antenna up about 55 feet above ground. At some distance, our signals should be very, very similar. But for some reason, they're not -- at any distance, except on perhaps rare occasion.

::Usually pinning down the difference between antennas isn't so difficult, but this one is slightly baffling.

::Conversely, my neighbor Neil K6SMF consistently beats me out on 17m when we side-by-side compare, and I can figure that one out: I'm using a smaller beam at 55' and Neil's using a monstrous 40' long boom monobander at about 80' above ground. We live only a mile apart. In most cases, especially at lower angles, Neil ought to be stronger, and he is. Makes perfect sense. Even the signal strength differentials reported make perfect sense: The difference is usually 3 to 6 dB, which is very believable for the antenna difference.

::"Benchmarks" can be anything, they needn't be a traceable standard. I think the more of them we use, the more accurate any accumulated data is.

WB2WIK/6

Reply to a comment by : G0GQK on 2007-02-22

One aspect of an antenna which people forget about is the direction and strength of the radiating lobes. The angles of the lobes are dependent on the height of the antenna above the earth and every piece of wire or aluminium tubing will radiate differently over a differing type of earth. At different heights the lobes may be useful to some parts of the earth but may be completely useless to another part. The ARRL handbook of many years ago told me that a non resonant piece of wire brought into resonance with a tuner is as efficient at radiating radio waves as a resonant piece of wire at the same frequency. It all depends on the length of the radiating wire. What is THE benchmark ? Who has the efficient antenna locally to make a comparison, which is over the same kind of ground, at the same height, and lined up in the same way ? This subject is, and always has been as long as it is wide and how long IS the piece of string ? However, I'll give you a benchmark ! A resonant dipole made by the worlds expert on wire antenna's, whether its strung up horizontally or vertically, will not "hear" as good on 20 metres as a cubic quad antenna at 50 feet, and that's a fact ! And you know what, I wish I'd got one ! Mel G0GQK
W7ETA2007-02-22
RE: Benchmarks
<Should I be looking for a way to defeat the 857's cautious approach to SWR?>

It simply means you can experience the joy of learning more about reflected power, voltage standing WAVES, how current varies with voltage, and why feed line loss can increase with increasing SWR.

Unfortunately, I didn't save one of W8JI's post, from many months ago, that filled in a lot of info I wasn't aware of.

73
Bob

PS: I like the article. For some reason, I think I understand the points Alan is providing, and why he didn't try for infinite accuracy in this instance.
Reply to a comment by : K9IUQ on 2007-02-22

W4LGH wrote I am done here! No hope.... ................................. K9IUQ says Ahh, another breath of fresh air. ................................. K6HWH wrote Should I be looking for a way to defeat the 857's cautious approach to SWR? .......................................... K9IUQ says: The way to defeat this cautious approach is called an antenna tuner. This cautious approach is done by *most* modern radios. This is why you see a lot of radios with built-in antenna tuners. K9IUQ
G0GQK2007-02-22
Benchmarks
One aspect of an antenna which people forget about is the direction and strength of the radiating lobes. The angles of the lobes are dependent on the height of the antenna above the earth and every piece of wire or aluminium tubing will radiate differently over a differing type of earth. At different heights the lobes may be useful to some parts of the earth but may be completely useless to another part.

The ARRL handbook of many years ago told me that a non resonant piece of wire brought into resonance with a tuner is as efficient at radiating radio waves as a resonant piece of wire at the same frequency. It all depends on the length of the radiating wire.

What is THE benchmark ? Who has the efficient antenna locally to make a comparison, which is over the same kind of ground, at the same height, and lined up in the same way ?

This subject is, and always has been as long as it is wide and how long IS the piece of string ?

However, I'll give you a benchmark ! A resonant dipole made by the worlds expert on wire antenna's, whether its strung up horizontally or vertically, will not "hear" as good on 20 metres as a cubic quad antenna at 50 feet, and that's a fact !

And you know what, I wish I'd got one !

Mel G0GQK
K0BG2007-02-22
RE: Benchmarks
We all could get into a real lengthy argument about receive gain verses transmit gain. As has been pointed out to me, to assume otherwise would affront the theories set down by Dr. Maxwell. Personally, I'm not in a position to dispute them, although of late others have. But that was not my point.

As Steve Katz, WB2WYK, reiterated, real-world performance is not based on (advertised or actual) gain. Nor should it be. Nor should it be based on a low SWR, or anecdotal references.

With respect to tuners, they have their place. I own three of them myself. But I don't use one to load up my lawn chair, and call it a great antenna just because I worked Timbuktu with it.

Alan, KØBG
www.k0bg.com
Reply to a comment by : K9IUQ on 2007-02-22

W4LGH wrote I am done here! No hope.... ................................. K9IUQ says Ahh, another breath of fresh air. ................................. K6HWH wrote Should I be looking for a way to defeat the 857's cautious approach to SWR? .......................................... K9IUQ says: The way to defeat this cautious approach is called an antenna tuner. This cautious approach is done by *most* modern radios. This is why you see a lot of radios with built-in antenna tuners. K9IUQ
K9IUQ2007-02-22
Benchmarks
N4KC wrote
At the same time, I'd suggest you visit http://www.w2du.com/ and check out some of the material there. As noted by others, W2DU, Walter Maxwell, has done more studying of the resonant/non-resonant antenna question than we could all do in a hundred years, including some very interesting and pragmatic applications of both types. His book is quite readable..

.......................................................

K9IUQ says
N4KC THANKYOU THANKYOU. I was unaware of this site and it is GREAT, just like Walter's Book Reflections which I own and has been worn thin over the years from use.
W2DU was the man when it came to SWR, antennas and dispelling all the ham antenna myths that get repeated over and over. If you can only own one antenna book, Get one of the Reflections Books from W2DU.

EVERYONE that has been reading this thread needs to go to the above website and read at least "Too Low An SWR Can Kill You" It is a classic and will put to bed many of the agruments you see in this thread. Everyone should print out Fig 1.1 on page 1.3 of chapter one. Some of this was in QST a few months ago. It will make all of us sleep better tonite knowing that high swr wont necessarily hurt our signals.

Thanks again for the link, you just made my day.

Stan K9IUQ



WB2WIK2007-02-22
RE: Benchmarks
Not all solid state rigs reduce output power beginning at VSWR = 1.5. That is ultra conservative.

The Ten Tec transceivers for years used a circuit breaker in the power supply to tell the transceiver when to "cut back power" due to high VSWR. They'd shut off! But until the breaker tripped, they'd keep transmitting.

My Drake TR-7, by published specification, provides 90% of its full rated output power into a 2:1 VSWR and doesn't "fold back" to 50% (which is still about 75W output power) until VSWR = 5:1.

That detail is listed here on the last page of the TR-7 brochure:

http://wb4hfn.com/DRAKE/DrakeCatalogsBrochures/Brochure_TR7_04B.htm

As such, the TR-7 hardly needs a tuner unless the user intends some pretty serious mismatches. Mine can easily produce 100W output power into a 3:1 mismatch, on any band. Without a tuner.

It's largely a matter of "headroom" for the power amplifying devices selected. Margins include current, voltage and heat. One problem with a little rig like the FT-857 is its PA devices are small and its PA heatsink is *very* small, not capable of carrying much heat away from the devices, even with a fan.

The TR-7 power amplifier heatsink alone (just the heatsink) is larger than the entire FT-857...

WB2WIK/6
Reply to a comment by : K6HWH on 2007-02-22

"Every solidstate radio I have ever owned started shutting down power at a 1.5 swr." What about this? I have a Yaesu 857 that does indeed crank down transmit power if the SWR is the least bit off, ostensibly to prevent damage to the output transistors. If even a SWR of 5 does not diminish appreciable the antenna's ability to radiate, isn't this a mistake? Should I be looking for a way to defeat the 857's cautious approach to SWR?
Reply to a comment by : K3AN on 2007-02-22

This article is evidence that you can't determine the usefulness or accuracy of an article by the number of words. If you want useful, accurate information on antennas, please visit the L.B. Cebik web site www.cebik.com. For the last time, there is nothing magical about resonant antennas.
Reply to a comment by : N3OX on 2007-02-22

Respectfully, W4LGH, I would like to point out that you are the one muddying the waters about a *resonant antenna* and its radiating effectiveness. It is not true that antenna element resonance has anything to do with coupling power into the electromagnetic field around the antenna. The *REAL* part of the antenna impedance has two components, the radiation resistance and the loss resistance. That fraction of the power which is associated with "dissipation" in the radiation resistance is the power that gets radiated. The fraction associated with dissipation in the loss resistance goes up as heat. The power in the reactive part of the impedance is simply stored in fields around the antenna. That means that an antenna with an impedance of 70+j0 and one with an impedance of 70+j500 are radiating exactly the same amount of power if you can feed that power to them in the first place. You need to match the antenna system to the transmitter but resonance of the antenna element itself has nothing at all to do with the transfer of that power to radiating electromagnetic fields. If you are supplying 100W to the antenna, 100W minus the antenna losses is radiated, no matter whether or not the antenna element is resonant. 73, Dan
Reply to a comment by : W4LGH on 2007-02-22

You see, here we go again, a good article is written, it contains some great info. Some additional articles are written taken it a little further. Then come the people who truely do not understand what is being said, and either go on what they have seen, or what somebody else who truely doesn't understand told them. ==================================================== Now... AA4PB writes..."at resonance the antenna is inducing more power into the atmosphere ---------------------------------------------------- Can you point us to a definitive text that proves this, or even claims it to be true?" ==================================================== Now with a call like this, this guy is at least an "ADVANCED" class if not an "EXTRA" class, what I said is basic "Physics 101" Resonance is a common thread which runs through almost every branch of physics, and yet a lot of people have never studied it. Without resonance we wouldn't have radio, television, music, or swings on playgrounds, not to mention cool gismos like Tesla coils. Of course, resonance also has its dark side. It occasionally causes a bridge to collapse, a helicopter to fly apart, or other inconveniences. Unlike black holes, time travel, and quantum mechanics, resonance is common place and easy to observe. Yet, it is one of the most striking and unexpected phenomenon in all of physics. It is relative to everything. Here is a good link to read about it...hopefully it will explain.. http://www.intuitor.com/resonance/circuits.html Ever heard the term, "Dip the Plate" when tuning? Notice how the plate current drops but your output increases? Wonder why that is? Could it be your tank circuit has been tuned to resonance? Hmmm...your antenna is an extension of your tank circuit. And to K9IUQ...who wrote..."Also resonance of the SYSTEM has nothing to do with how well the antenna radiates. This is determined by MANY other factors. I have a wonderful Dummy load antenna under my desk that is resonant on all HF bands, however it doesnt seem to radiate very well since I haven't worked too many people with it."... I give up here, this guy just isn't with the program...A dummy LOAD is NOT resonate, it is a resistive LOAD designed to burn up the power by turning it into HEAT! Thats why they call it a dummy LOAD! (key word there is LOAD) Man..you guys say you want elmers, if you truely do not understand something, thats ok, there are people who do understand, and more than willing to help. 73 de W4LGH Alan http://www.w4lgh.com
Reply to a comment by : AA4PB on 2007-02-22

at resonance the antenna is inducing more power into the atmosphere ---------------------------------------------------- Can you point us to a definitive text that proves this, or even claims it to be true?
Reply to a comment by : K9IUQ on 2007-02-22

One TRUE statement was made, a RESONATE antenna will work BETTER than a NON_RESONATE antenna. People do NOT understand resonance ..................................................... The above is an false statement. An Antenna is resonant at ONLY ONE frequency. At any other frequency it is non-resonant. We all use non-resonant antennas (including you) on a daily basis. We make the antenna SYSTEM resonant with a tuner of one kind or another or live with SWR higher than 1:1. Agreed - the whole SYSTEM must be resonance -from the radio to the antenna. It makes little difference if the antenna itself is resonance or not.Many of the best performing wire antennas are non-resonant fed with open wire feeders and an antenna tuner. Also resonance of the SYSTEM has nothing to do with how well the antenna radiates. This is determined by MANY other factors. I have a wonderful Dummy load antenna under my desk that is resonant on all HF bands, however it doesnt seem to radiate very well since I haven't worked too many people with it. Please Pick Up an antenna Book like "Reflections" and learn the facts instead of trying to sell me 'some wonderful ocean front property in Arizona " K9IUQ
K9IUQ2007-02-22
Benchmarks
W4LGH wrote

I am done here! No hope....
.................................

K9IUQ says

Ahh, another breath of fresh air.


.................................

K6HWH wrote
Should I be looking for a way to defeat the 857's cautious approach to SWR?
..........................................
K9IUQ says:
The way to defeat this cautious approach is called an antenna tuner. This cautious approach is done by *most* modern radios. This is why you see a lot of radios with built-in antenna tuners.

K9IUQ

N4KC2007-02-22
RE: Benchmarks
Actually I really enjoy discussions such as this one, and there have been some good, well-reasoned responses from every side of the various arguments...even if we have strayed a good bit from the author's original topic. W4LGH, thank you for posting the links and I will certainly take a look at them.

At the same time, I'd suggest you visit http://www.w2du.com/ and check out some of the material there. As noted by others, W2DU, Walter Maxwell, has done more studying of the resonant/non-resonant antenna question than we could all do in a hundred years, including some very interesting and pragmatic applications of both types. His book is quite readable...or at least the first half of it is! He left me behind after that. And he makes a compelling case for what several of us have been saying in this very interesting and lively thread.

Also, I salute the tone of the arguments here. Only a few ALL CAP comments, no flagrant flames, and not one mention of the no-code license!

73,

Don N4KC
www.donkeith.com

Reply to a comment by : K9IUQ on 2007-02-22

To W4LGH: You Wrote: Now with a call like this, this guy is at least an "ADVANCED" class if not an "EXTRA" class, what I said is basic ....................................................... K9IUQ says Perhaps you could explain to me WHY Extra class hams with egos ALWAYS try to belittle a ham that is not an Extra? I have NEVER been able to figure this one out? This fellow could be a TECH and BE twice as intelligent as you. Ham Class does not relate to intelligence or knowledge. ..................................................... W4LGH Wrote:I give up here, this guy just isn't with the program...A dummy LOAD is NOT resonate, it is a resistive LOAD designed to burn up the power by turning it into HEAT! Thats why they call it a dummy LOAD! (key word there is LOAD) ...................................................... K9IUQ says Thank goodness I never had your program. From the ARRL handbook - The Key word here is LOAD as in antenna load. To a transmitter an antenna presents a Load. "In practice,real antenna loads are seldom purely resistive or exactly 50 ohms; they often exhibit SWRs of 2:1 or greater on some frequencies." .................................................... And Posted By N3OX Respectfully, W4LGH, I would like to point out that you are the one muddying the waters about a *resonant antenna* and its radiating effectiveness. It is not true that antenna element resonance has anything to do with coupling power into the electromagnetic field around the antenna. ............ And K3AN posted For the last time, there is nothing magical about resonant antennas. ......................................................... K9IUQ Says; N3OX and K3AN, That was like a breath of fresh air, some Hams do "get it". And If you want useful, accurate information on antennas,you won't find it on ham forums, go to respected people like the L.B. Cebik web site www.cebik.com. and Beg, Borrow, or Steal a copy of Reflections, one of the most readable tomes on Antennas, SWR and Ham Myths. K9IUQ
K6HWH2007-02-22
RE: Benchmarks
"Every solidstate radio I have ever owned started shutting down power at a 1.5 swr."

What about this? I have a Yaesu 857 that does indeed crank down transmit power if the SWR is the least bit off, ostensibly to prevent damage to the output transistors. If even a SWR of 5 does not diminish appreciable the antenna's ability to radiate, isn't this a mistake? Should I be looking for a way to defeat the 857's cautious approach to SWR?
Reply to a comment by : K3AN on 2007-02-22

This article is evidence that you can't determine the usefulness or accuracy of an article by the number of words. If you want useful, accurate information on antennas, please visit the L.B. Cebik web site www.cebik.com. For the last time, there is nothing magical about resonant antennas.
Reply to a comment by : N3OX on 2007-02-22

Respectfully, W4LGH, I would like to point out that you are the one muddying the waters about a *resonant antenna* and its radiating effectiveness. It is not true that antenna element resonance has anything to do with coupling power into the electromagnetic field around the antenna. The *REAL* part of the antenna impedance has two components, the radiation resistance and the loss resistance. That fraction of the power which is associated with "dissipation" in the radiation resistance is the power that gets radiated. The fraction associated with dissipation in the loss resistance goes up as heat. The power in the reactive part of the impedance is simply stored in fields around the antenna. That means that an antenna with an impedance of 70+j0 and one with an impedance of 70+j500 are radiating exactly the same amount of power if you can feed that power to them in the first place. You need to match the antenna system to the transmitter but resonance of the antenna element itself has nothing at all to do with the transfer of that power to radiating electromagnetic fields. If you are supplying 100W to the antenna, 100W minus the antenna losses is radiated, no matter whether or not the antenna element is resonant. 73, Dan
Reply to a comment by : W4LGH on 2007-02-22

You see, here we go again, a good article is written, it contains some great info. Some additional articles are written taken it a little further. Then come the people who truely do not understand what is being said, and either go on what they have seen, or what somebody else who truely doesn't understand told them. ==================================================== Now... AA4PB writes..."at resonance the antenna is inducing more power into the atmosphere ---------------------------------------------------- Can you point us to a definitive text that proves this, or even claims it to be true?" ==================================================== Now with a call like this, this guy is at least an "ADVANCED" class if not an "EXTRA" class, what I said is basic "Physics 101" Resonance is a common thread which runs through almost every branch of physics, and yet a lot of people have never studied it. Without resonance we wouldn't have radio, television, music, or swings on playgrounds, not to mention cool gismos like Tesla coils. Of course, resonance also has its dark side. It occasionally causes a bridge to collapse, a helicopter to fly apart, or other inconveniences. Unlike black holes, time travel, and quantum mechanics, resonance is common place and easy to observe. Yet, it is one of the most striking and unexpected phenomenon in all of physics. It is relative to everything. Here is a good link to read about it...hopefully it will explain.. http://www.intuitor.com/resonance/circuits.html Ever heard the term, "Dip the Plate" when tuning? Notice how the plate current drops but your output increases? Wonder why that is? Could it be your tank circuit has been tuned to resonance? Hmmm...your antenna is an extension of your tank circuit. And to K9IUQ...who wrote..."Also resonance of the SYSTEM has nothing to do with how well the antenna radiates. This is determined by MANY other factors. I have a wonderful Dummy load antenna under my desk that is resonant on all HF bands, however it doesnt seem to radiate very well since I haven't worked too many people with it."... I give up here, this guy just isn't with the program...A dummy LOAD is NOT resonate, it is a resistive LOAD designed to burn up the power by turning it into HEAT! Thats why they call it a dummy LOAD! (key word there is LOAD) Man..you guys say you want elmers, if you truely do not understand something, thats ok, there are people who do understand, and more than willing to help. 73 de W4LGH Alan http://www.w4lgh.com
Reply to a comment by : AA4PB on 2007-02-22

at resonance the antenna is inducing more power into the atmosphere ---------------------------------------------------- Can you point us to a definitive text that proves this, or even claims it to be true?
Reply to a comment by : K9IUQ on 2007-02-22

One TRUE statement was made, a RESONATE antenna will work BETTER than a NON_RESONATE antenna. People do NOT understand resonance ..................................................... The above is an false statement. An Antenna is resonant at ONLY ONE frequency. At any other frequency it is non-resonant. We all use non-resonant antennas (including you) on a daily basis. We make the antenna SYSTEM resonant with a tuner of one kind or another or live with SWR higher than 1:1. Agreed - the whole SYSTEM must be resonance -from the radio to the antenna. It makes little difference if the antenna itself is resonance or not.Many of the best performing wire antennas are non-resonant fed with open wire feeders and an antenna tuner. Also resonance of the SYSTEM has nothing to do with how well the antenna radiates. This is determined by MANY other factors. I have a wonderful Dummy load antenna under my desk that is resonant on all HF bands, however it doesnt seem to radiate very well since I haven't worked too many people with it. Please Pick Up an antenna Book like "Reflections" and learn the facts instead of trying to sell me 'some wonderful ocean front property in Arizona " K9IUQ
W4LGH2007-02-22
RE: Benchmarks
To W4LGH:
You Wrote: Now with a call like this, this guy is at least an "ADVANCED" class if not an "EXTRA" class, what I said is basic
.......................................................
K9IUQ says

Perhaps you could explain to me WHY Extra class hams with egos ALWAYS try to belittle a ham that is not an Extra? I have NEVER been able to figure this one out?
This fellow could be a TECH and BE twice as intelligent as you. Ham Class does not relate to intelligence or knowledge.
.....................................................

I guess you missed that one too! An AA call is either an ADVANCED or EXTRA class license, so I was picking on the ADVANCED/EXTRA class, and not the Tech. Someone who holds these class license should understand resonance. Stop reading what you want it to say and read what I said.

I am done here! No hope....
Reply to a comment by : K9IUQ on 2007-02-22

To W4LGH: You Wrote: Now with a call like this, this guy is at least an "ADVANCED" class if not an "EXTRA" class, what I said is basic ....................................................... K9IUQ says Perhaps you could explain to me WHY Extra class hams with egos ALWAYS try to belittle a ham that is not an Extra? I have NEVER been able to figure this one out? This fellow could be a TECH and BE twice as intelligent as you. Ham Class does not relate to intelligence or knowledge. ..................................................... W4LGH Wrote:I give up here, this guy just isn't with the program...A dummy LOAD is NOT resonate, it is a resistive LOAD designed to burn up the power by turning it into HEAT! Thats why they call it a dummy LOAD! (key word there is LOAD) ...................................................... K9IUQ says Thank goodness I never had your program. From the ARRL handbook - The Key word here is LOAD as in antenna load. To a transmitter an antenna presents a Load. "In practice,real antenna loads are seldom purely resistive or exactly 50 ohms; they often exhibit SWRs of 2:1 or greater on some frequencies." .................................................... And Posted By N3OX Respectfully, W4LGH, I would like to point out that you are the one muddying the waters about a *resonant antenna* and its radiating effectiveness. It is not true that antenna element resonance has anything to do with coupling power into the electromagnetic field around the antenna. ............ And K3AN posted For the last time, there is nothing magical about resonant antennas. ......................................................... K9IUQ Says; N3OX and K3AN, That was like a breath of fresh air, some Hams do "get it". And If you want useful, accurate information on antennas,you won't find it on ham forums, go to respected people like the L.B. Cebik web site www.cebik.com. and Beg, Borrow, or Steal a copy of Reflections, one of the most readable tomes on Antennas, SWR and Ham Myths. K9IUQ
WB2WIK2007-02-22
RE: Benchmarks
Carl, W9PMZ, I didn't miss the point at all.

I believe you did.

The author never stated the reciprocity theory wasn't true. He did state this:

"Yet another often-heard statement is, I can work anything I can hear. Can you now? The fact is (contrary to popular belief), antennas are NOT reciprocal in their transmit verses receive performance."

He referenced "transmit versus receive *performance*" which in my interpretation, and I think any common interpretation, means exactly what it says: Performance. Not gain, nor pattern. Performance. Performance is how it actually works for you, on the air.

In the real work, on the air, where the rubber meets the road, HF antennas do not often provide reciprocal performance in that they don't necessarily work as well for receiving stations and in turn having those stations receive you -- even when they are perfectly matched. Reciprocity only works in an anechoic chamber, or on an open antenna range where the yardsticks for measurement involve a signal source and a method of detecting that source at a high signal level.

As soon as you replace that detector with a receiver and place it miles away, *performance* often changes.

Semantics, perhaps, but ham radio is about making contacts, not laboratory measurements.

WB2WIK/6
Reply to a comment by : K3AN on 2007-02-22

This article is evidence that you can't determine the usefulness or accuracy of an article by the number of words. If you want useful, accurate information on antennas, please visit the L.B. Cebik web site www.cebik.com. For the last time, there is nothing magical about resonant antennas.
Reply to a comment by : N3OX on 2007-02-22

Respectfully, W4LGH, I would like to point out that you are the one muddying the waters about a *resonant antenna* and its radiating effectiveness. It is not true that antenna element resonance has anything to do with coupling power into the electromagnetic field around the antenna. The *REAL* part of the antenna impedance has two components, the radiation resistance and the loss resistance. That fraction of the power which is associated with "dissipation" in the radiation resistance is the power that gets radiated. The fraction associated with dissipation in the loss resistance goes up as heat. The power in the reactive part of the impedance is simply stored in fields around the antenna. That means that an antenna with an impedance of 70+j0 and one with an impedance of 70+j500 are radiating exactly the same amount of power if you can feed that power to them in the first place. You need to match the antenna system to the transmitter but resonance of the antenna element itself has nothing at all to do with the transfer of that power to radiating electromagnetic fields. If you are supplying 100W to the antenna, 100W minus the antenna losses is radiated, no matter whether or not the antenna element is resonant. 73, Dan
Reply to a comment by : W4LGH on 2007-02-22

You see, here we go again, a good article is written, it contains some great info. Some additional articles are written taken it a little further. Then come the people who truely do not understand what is being said, and either go on what they have seen, or what somebody else who truely doesn't understand told them. ==================================================== Now... AA4PB writes..."at resonance the antenna is inducing more power into the atmosphere ---------------------------------------------------- Can you point us to a definitive text that proves this, or even claims it to be true?" ==================================================== Now with a call like this, this guy is at least an "ADVANCED" class if not an "EXTRA" class, what I said is basic "Physics 101" Resonance is a common thread which runs through almost every branch of physics, and yet a lot of people have never studied it. Without resonance we wouldn't have radio, television, music, or swings on playgrounds, not to mention cool gismos like Tesla coils. Of course, resonance also has its dark side. It occasionally causes a bridge to collapse, a helicopter to fly apart, or other inconveniences. Unlike black holes, time travel, and quantum mechanics, resonance is common place and easy to observe. Yet, it is one of the most striking and unexpected phenomenon in all of physics. It is relative to everything. Here is a good link to read about it...hopefully it will explain.. http://www.intuitor.com/resonance/circuits.html Ever heard the term, "Dip the Plate" when tuning? Notice how the plate current drops but your output increases? Wonder why that is? Could it be your tank circuit has been tuned to resonance? Hmmm...your antenna is an extension of your tank circuit. And to K9IUQ...who wrote..."Also resonance of the SYSTEM has nothing to do with how well the antenna radiates. This is determined by MANY other factors. I have a wonderful Dummy load antenna under my desk that is resonant on all HF bands, however it doesnt seem to radiate very well since I haven't worked too many people with it."... I give up here, this guy just isn't with the program...A dummy LOAD is NOT resonate, it is a resistive LOAD designed to burn up the power by turning it into HEAT! Thats why they call it a dummy LOAD! (key word there is LOAD) Man..you guys say you want elmers, if you truely do not understand something, thats ok, there are people who do understand, and more than willing to help. 73 de W4LGH Alan http://www.w4lgh.com
Reply to a comment by : AA4PB on 2007-02-22

at resonance the antenna is inducing more power into the atmosphere ---------------------------------------------------- Can you point us to a definitive text that proves this, or even claims it to be true?
Reply to a comment by : K9IUQ on 2007-02-22

One TRUE statement was made, a RESONATE antenna will work BETTER than a NON_RESONATE antenna. People do NOT understand resonance ..................................................... The above is an false statement. An Antenna is resonant at ONLY ONE frequency. At any other frequency it is non-resonant. We all use non-resonant antennas (including you) on a daily basis. We make the antenna SYSTEM resonant with a tuner of one kind or another or live with SWR higher than 1:1. Agreed - the whole SYSTEM must be resonance -from the radio to the antenna. It makes little difference if the antenna itself is resonance or not.Many of the best performing wire antennas are non-resonant fed with open wire feeders and an antenna tuner. Also resonance of the SYSTEM has nothing to do with how well the antenna radiates. This is determined by MANY other factors. I have a wonderful Dummy load antenna under my desk that is resonant on all HF bands, however it doesnt seem to radiate very well since I haven't worked too many people with it. Please Pick Up an antenna Book like "Reflections" and learn the facts instead of trying to sell me 'some wonderful ocean front property in Arizona " K9IUQ
K9IUQ2007-02-22
Benchmarks
To W4LGH:
You Wrote: Now with a call like this, this guy is at least an "ADVANCED" class if not an "EXTRA" class, what I said is basic
.......................................................
K9IUQ says

Perhaps you could explain to me WHY Extra class hams with egos ALWAYS try to belittle a ham that is not an Extra? I have NEVER been able to figure this one out?
This fellow could be a TECH and BE twice as intelligent as you. Ham Class does not relate to intelligence or knowledge.
.....................................................

W4LGH Wrote:I give up here, this guy just isn't with the program...A dummy LOAD is NOT resonate, it is a resistive LOAD designed to burn up the power by turning it into HEAT! Thats why they call it a dummy LOAD! (key word there is LOAD)

......................................................
K9IUQ says

Thank goodness I never had your program. From the ARRL handbook - The Key word here is LOAD as in antenna load.
To a transmitter an antenna presents a Load.

"In practice,real antenna loads are seldom purely
resistive or exactly 50 ohms; they often
exhibit SWRs of 2:1 or greater on some
frequencies."

....................................................
And Posted By N3OX

Respectfully, W4LGH, I would like to point out that you are the one muddying the waters about a *resonant antenna* and its radiating effectiveness.
It is not true that antenna element resonance has anything to do with coupling power into the electromagnetic field around the antenna.

............
And K3AN posted
For the last time, there is nothing magical about resonant antennas.

.........................................................
K9IUQ Says;

N3OX and K3AN, That was like a breath of fresh air, some Hams do "get it".

And If you want useful, accurate information on antennas,you won't find it on ham forums, go to respected people like the L.B. Cebik web site www.cebik.com. and Beg, Borrow, or Steal a copy of Reflections, one of the most readable tomes on Antennas, SWR and Ham Myths.

K9IUQ









K3AN2007-02-22
RE: Benchmarks
This article is evidence that you can't determine the usefulness or accuracy of an article by the number of words.

If you want useful, accurate information on antennas, please visit the L.B. Cebik web site www.cebik.com.

For the last time, there is nothing magical about resonant antennas.
Reply to a comment by : N3OX on 2007-02-22

Respectfully, W4LGH, I would like to point out that you are the one muddying the waters about a *resonant antenna* and its radiating effectiveness. It is not true that antenna element resonance has anything to do with coupling power into the electromagnetic field around the antenna. The *REAL* part of the antenna impedance has two components, the radiation resistance and the loss resistance. That fraction of the power which is associated with "dissipation" in the radiation resistance is the power that gets radiated. The fraction associated with dissipation in the loss resistance goes up as heat. The power in the reactive part of the impedance is simply stored in fields around the antenna. That means that an antenna with an impedance of 70+j0 and one with an impedance of 70+j500 are radiating exactly the same amount of power if you can feed that power to them in the first place. You need to match the antenna system to the transmitter but resonance of the antenna element itself has nothing at all to do with the transfer of that power to radiating electromagnetic fields. If you are supplying 100W to the antenna, 100W minus the antenna losses is radiated, no matter whether or not the antenna element is resonant. 73, Dan
Reply to a comment by : W4LGH on 2007-02-22

You see, here we go again, a good article is written, it contains some great info. Some additional articles are written taken it a little further. Then come the people who truely do not understand what is being said, and either go on what they have seen, or what somebody else who truely doesn't understand told them. ==================================================== Now... AA4PB writes..."at resonance the antenna is inducing more power into the atmosphere ---------------------------------------------------- Can you point us to a definitive text that proves this, or even claims it to be true?" ==================================================== Now with a call like this, this guy is at least an "ADVANCED" class if not an "EXTRA" class, what I said is basic "Physics 101" Resonance is a common thread which runs through almost every branch of physics, and yet a lot of people have never studied it. Without resonance we wouldn't have radio, television, music, or swings on playgrounds, not to mention cool gismos like Tesla coils. Of course, resonance also has its dark side. It occasionally causes a bridge to collapse, a helicopter to fly apart, or other inconveniences. Unlike black holes, time travel, and quantum mechanics, resonance is common place and easy to observe. Yet, it is one of the most striking and unexpected phenomenon in all of physics. It is relative to everything. Here is a good link to read about it...hopefully it will explain.. http://www.intuitor.com/resonance/circuits.html Ever heard the term, "Dip the Plate" when tuning? Notice how the plate current drops but your output increases? Wonder why that is? Could it be your tank circuit has been tuned to resonance? Hmmm...your antenna is an extension of your tank circuit. And to K9IUQ...who wrote..."Also resonance of the SYSTEM has nothing to do with how well the antenna radiates. This is determined by MANY other factors. I have a wonderful Dummy load antenna under my desk that is resonant on all HF bands, however it doesnt seem to radiate very well since I haven't worked too many people with it."... I give up here, this guy just isn't with the program...A dummy LOAD is NOT resonate, it is a resistive LOAD designed to burn up the power by turning it into HEAT! Thats why they call it a dummy LOAD! (key word there is LOAD) Man..you guys say you want elmers, if you truely do not understand something, thats ok, there are people who do understand, and more than willing to help. 73 de W4LGH Alan http://www.w4lgh.com
Reply to a comment by : AA4PB on 2007-02-22

at resonance the antenna is inducing more power into the atmosphere ---------------------------------------------------- Can you point us to a definitive text that proves this, or even claims it to be true?
Reply to a comment by : K9IUQ on 2007-02-22

One TRUE statement was made, a RESONATE antenna will work BETTER than a NON_RESONATE antenna. People do NOT understand resonance ..................................................... The above is an false statement. An Antenna is resonant at ONLY ONE frequency. At any other frequency it is non-resonant. We all use non-resonant antennas (including you) on a daily basis. We make the antenna SYSTEM resonant with a tuner of one kind or another or live with SWR higher than 1:1. Agreed - the whole SYSTEM must be resonance -from the radio to the antenna. It makes little difference if the antenna itself is resonance or not.Many of the best performing wire antennas are non-resonant fed with open wire feeders and an antenna tuner. Also resonance of the SYSTEM has nothing to do with how well the antenna radiates. This is determined by MANY other factors. I have a wonderful Dummy load antenna under my desk that is resonant on all HF bands, however it doesnt seem to radiate very well since I haven't worked too many people with it. Please Pick Up an antenna Book like "Reflections" and learn the facts instead of trying to sell me 'some wonderful ocean front property in Arizona " K9IUQ
W4LGH2007-02-22
RE: Benchmarks
Dan..What you say holds some facts, but not total truths. You really need to read the 2nd article link that I posted several up. Where it says....

"The very slight motion of electrons up and down an antenna is enough to cause electromagnetic waves to radiate out the sides of the antenna at the same frequency as the variable voltage applied to it. These are used for transmitting radio and television signals as well as other forms of wireless communication.

Like sound, when electrical waves at a defined frequency hit the end of an antenna they are reflected backwards and form a standing wave in the antenna. Antenna waves move at the speed of light (3 x 10 8 m/s) and so the travel time from one end of the antenna to the other is pretty quick.

The electrical waves created on antennas typically have a fixed wavelength. If the length of the antenna is wisely chosen it's possible to make it resonate. The free end of an antenna acts like an open circuit. Voltage drop is maximum across an open circuit and zero across a short circuit. Hence the end of an antenna forms an anti-node or area of maximum voltage or e-field strength. A node is a point which has zero e-field. The distance between an anti-node and node is a quarter of a wavelength."

And in another portion it talks about an antenna working better if it is resonate...
"Antenna design is very complex and requires a lot of time and study to master. However, any antenna will have to oscillate charged particles in order to transmit radio signals and will tend to do this best if the antenna is resonating."

Its amazing some of the ideas, notions and myths that people believe. However, I will shut up and stop posting.. Only trying to help. No hard feeling here.

73 de W4LGH Alan
http://www.w4lgh.com

Reply to a comment by : N3OX on 2007-02-22

Respectfully, W4LGH, I would like to point out that you are the one muddying the waters about a *resonant antenna* and its radiating effectiveness. It is not true that antenna element resonance has anything to do with coupling power into the electromagnetic field around the antenna. The *REAL* part of the antenna impedance has two components, the radiation resistance and the loss resistance. That fraction of the power which is associated with "dissipation" in the radiation resistance is the power that gets radiated. The fraction associated with dissipation in the loss resistance goes up as heat. The power in the reactive part of the impedance is simply stored in fields around the antenna. That means that an antenna with an impedance of 70+j0 and one with an impedance of 70+j500 are radiating exactly the same amount of power if you can feed that power to them in the first place. You need to match the antenna system to the transmitter but resonance of the antenna element itself has nothing at all to do with the transfer of that power to radiating electromagnetic fields. If you are supplying 100W to the antenna, 100W minus the antenna losses is radiated, no matter whether or not the antenna element is resonant. 73, Dan
Reply to a comment by : W4LGH on 2007-02-22

You see, here we go again, a good article is written, it contains some great info. Some additional articles are written taken it a little further. Then come the people who truely do not understand what is being said, and either go on what they have seen, or what somebody else who truely doesn't understand told them. ==================================================== Now... AA4PB writes..."at resonance the antenna is inducing more power into the atmosphere ---------------------------------------------------- Can you point us to a definitive text that proves this, or even claims it to be true?" ==================================================== Now with a call like this, this guy is at least an "ADVANCED" class if not an "EXTRA" class, what I said is basic "Physics 101" Resonance is a common thread which runs through almost every branch of physics, and yet a lot of people have never studied it. Without resonance we wouldn't have radio, television, music, or swings on playgrounds, not to mention cool gismos like Tesla coils. Of course, resonance also has its dark side. It occasionally causes a bridge to collapse, a helicopter to fly apart, or other inconveniences. Unlike black holes, time travel, and quantum mechanics, resonance is common place and easy to observe. Yet, it is one of the most striking and unexpected phenomenon in all of physics. It is relative to everything. Here is a good link to read about it...hopefully it will explain.. http://www.intuitor.com/resonance/circuits.html Ever heard the term, "Dip the Plate" when tuning? Notice how the plate current drops but your output increases? Wonder why that is? Could it be your tank circuit has been tuned to resonance? Hmmm...your antenna is an extension of your tank circuit. And to K9IUQ...who wrote..."Also resonance of the SYSTEM has nothing to do with how well the antenna radiates. This is determined by MANY other factors. I have a wonderful Dummy load antenna under my desk that is resonant on all HF bands, however it doesnt seem to radiate very well since I haven't worked too many people with it."... I give up here, this guy just isn't with the program...A dummy LOAD is NOT resonate, it is a resistive LOAD designed to burn up the power by turning it into HEAT! Thats why they call it a dummy LOAD! (key word there is LOAD) Man..you guys say you want elmers, if you truely do not understand something, thats ok, there are people who do understand, and more than willing to help. 73 de W4LGH Alan http://www.w4lgh.com
Reply to a comment by : AA4PB on 2007-02-22

at resonance the antenna is inducing more power into the atmosphere ---------------------------------------------------- Can you point us to a definitive text that proves this, or even claims it to be true?
Reply to a comment by : K9IUQ on 2007-02-22

One TRUE statement was made, a RESONATE antenna will work BETTER than a NON_RESONATE antenna. People do NOT understand resonance ..................................................... The above is an false statement. An Antenna is resonant at ONLY ONE frequency. At any other frequency it is non-resonant. We all use non-resonant antennas (including you) on a daily basis. We make the antenna SYSTEM resonant with a tuner of one kind or another or live with SWR higher than 1:1. Agreed - the whole SYSTEM must be resonance -from the radio to the antenna. It makes little difference if the antenna itself is resonance or not.Many of the best performing wire antennas are non-resonant fed with open wire feeders and an antenna tuner. Also resonance of the SYSTEM has nothing to do with how well the antenna radiates. This is determined by MANY other factors. I have a wonderful Dummy load antenna under my desk that is resonant on all HF bands, however it doesnt seem to radiate very well since I haven't worked too many people with it. Please Pick Up an antenna Book like "Reflections" and learn the facts instead of trying to sell me 'some wonderful ocean front property in Arizona " K9IUQ
W9PMZ2007-02-22
RE: Benchmarks
"While W9PMZ has a good point about antenna *radiation pattern* being reciprocal for transmitting and receiving, this is another theory that lacks real-world relevance when applied to the HF bands. It starts to become seriously usable at VHF, UHF, SHF, EHF and above, where noise levels are low. "

Missed the point, the theory hold up at HF, VHF, UFH.... But, there are other factors that cause issues, such as noise that present in the real world that favor some antennas for RX over TX. But this has absolutely nothing to do with the premise of antenna recprocity.

73,

Carl - W9PMZ
Reply to a comment by : N3OX on 2007-02-22

Respectfully, W4LGH, I would like to point out that you are the one muddying the waters about a *resonant antenna* and its radiating effectiveness. It is not true that antenna element resonance has anything to do with coupling power into the electromagnetic field around the antenna. The *REAL* part of the antenna impedance has two components, the radiation resistance and the loss resistance. That fraction of the power which is associated with "dissipation" in the radiation resistance is the power that gets radiated. The fraction associated with dissipation in the loss resistance goes up as heat. The power in the reactive part of the impedance is simply stored in fields around the antenna. That means that an antenna with an impedance of 70+j0 and one with an impedance of 70+j500 are radiating exactly the same amount of power if you can feed that power to them in the first place. You need to match the antenna system to the transmitter but resonance of the antenna element itself has nothing at all to do with the transfer of that power to radiating electromagnetic fields. If you are supplying 100W to the antenna, 100W minus the antenna losses is radiated, no matter whether or not the antenna element is resonant. 73, Dan
Reply to a comment by : W4LGH on 2007-02-22

You see, here we go again, a good article is written, it contains some great info. Some additional articles are written taken it a little further. Then come the people who truely do not understand what is being said, and either go on what they have seen, or what somebody else who truely doesn't understand told them. ==================================================== Now... AA4PB writes..."at resonance the antenna is inducing more power into the atmosphere ---------------------------------------------------- Can you point us to a definitive text that proves this, or even claims it to be true?" ==================================================== Now with a call like this, this guy is at least an "ADVANCED" class if not an "EXTRA" class, what I said is basic "Physics 101" Resonance is a common thread which runs through almost every branch of physics, and yet a lot of people have never studied it. Without resonance we wouldn't have radio, television, music, or swings on playgrounds, not to mention cool gismos like Tesla coils. Of course, resonance also has its dark side. It occasionally causes a bridge to collapse, a helicopter to fly apart, or other inconveniences. Unlike black holes, time travel, and quantum mechanics, resonance is common place and easy to observe. Yet, it is one of the most striking and unexpected phenomenon in all of physics. It is relative to everything. Here is a good link to read about it...hopefully it will explain.. http://www.intuitor.com/resonance/circuits.html Ever heard the term, "Dip the Plate" when tuning? Notice how the plate current drops but your output increases? Wonder why that is? Could it be your tank circuit has been tuned to resonance? Hmmm...your antenna is an extension of your tank circuit. And to K9IUQ...who wrote..."Also resonance of the SYSTEM has nothing to do with how well the antenna radiates. This is determined by MANY other factors. I have a wonderful Dummy load antenna under my desk that is resonant on all HF bands, however it doesnt seem to radiate very well since I haven't worked too many people with it."... I give up here, this guy just isn't with the program...A dummy LOAD is NOT resonate, it is a resistive LOAD designed to burn up the power by turning it into HEAT! Thats why they call it a dummy LOAD! (key word there is LOAD) Man..you guys say you want elmers, if you truely do not understand something, thats ok, there are people who do understand, and more than willing to help. 73 de W4LGH Alan http://www.w4lgh.com
Reply to a comment by : AA4PB on 2007-02-22

at resonance the antenna is inducing more power into the atmosphere ---------------------------------------------------- Can you point us to a definitive text that proves this, or even claims it to be true?
Reply to a comment by : K9IUQ on 2007-02-22

One TRUE statement was made, a RESONATE antenna will work BETTER than a NON_RESONATE antenna. People do NOT understand resonance ..................................................... The above is an false statement. An Antenna is resonant at ONLY ONE frequency. At any other frequency it is non-resonant. We all use non-resonant antennas (including you) on a daily basis. We make the antenna SYSTEM resonant with a tuner of one kind or another or live with SWR higher than 1:1. Agreed - the whole SYSTEM must be resonance -from the radio to the antenna. It makes little difference if the antenna itself is resonance or not.Many of the best performing wire antennas are non-resonant fed with open wire feeders and an antenna tuner. Also resonance of the SYSTEM has nothing to do with how well the antenna radiates. This is determined by MANY other factors. I have a wonderful Dummy load antenna under my desk that is resonant on all HF bands, however it doesnt seem to radiate very well since I haven't worked too many people with it. Please Pick Up an antenna Book like "Reflections" and learn the facts instead of trying to sell me 'some wonderful ocean front property in Arizona " K9IUQ
N1XBP2007-02-22
RE: Benchmarks
Maybe a bit of the confusion would be cleared up if we remember that 1:1 SWR is not the same thing as resonance, really.

Can someone give us the real definition of a resonant antenna? Is it simply when Inductive reactance and Capacitive reactance are equal and opposite? Wouldn't that mean a tuner, which adds or subtracts capacitance or inductance, would make the antenna system resonant? Although, I'm often reading that is untrue.

It seems to me that theoretically you could have an antenna where the radiation resistance was as high as possible and non reactive impedance was as low as possible, and total system impedance was matched to the transmitter to produce low feed line loss, but it wouldn't necessarily be resonant..

But I confess I'm not an expert on that particular subject.
Reply to a comment by : N3OX on 2007-02-22

Respectfully, W4LGH, I would like to point out that you are the one muddying the waters about a *resonant antenna* and its radiating effectiveness. It is not true that antenna element resonance has anything to do with coupling power into the electromagnetic field around the antenna. The *REAL* part of the antenna impedance has two components, the radiation resistance and the loss resistance. That fraction of the power which is associated with "dissipation" in the radiation resistance is the power that gets radiated. The fraction associated with dissipation in the loss resistance goes up as heat. The power in the reactive part of the impedance is simply stored in fields around the antenna. That means that an antenna with an impedance of 70+j0 and one with an impedance of 70+j500 are radiating exactly the same amount of power if you can feed that power to them in the first place. You need to match the antenna system to the transmitter but resonance of the antenna element itself has nothing at all to do with the transfer of that power to radiating electromagnetic fields. If you are supplying 100W to the antenna, 100W minus the antenna losses is radiated, no matter whether or not the antenna element is resonant. 73, Dan
Reply to a comment by : W4LGH on 2007-02-22

You see, here we go again, a good article is written, it contains some great info. Some additional articles are written taken it a little further. Then come the people who truely do not understand what is being said, and either go on what they have seen, or what somebody else who truely doesn't understand told them. ==================================================== Now... AA4PB writes..."at resonance the antenna is inducing more power into the atmosphere ---------------------------------------------------- Can you point us to a definitive text that proves this, or even claims it to be true?" ==================================================== Now with a call like this, this guy is at least an "ADVANCED" class if not an "EXTRA" class, what I said is basic "Physics 101" Resonance is a common thread which runs through almost every branch of physics, and yet a lot of people have never studied it. Without resonance we wouldn't have radio, television, music, or swings on playgrounds, not to mention cool gismos like Tesla coils. Of course, resonance also has its dark side. It occasionally causes a bridge to collapse, a helicopter to fly apart, or other inconveniences. Unlike black holes, time travel, and quantum mechanics, resonance is common place and easy to observe. Yet, it is one of the most striking and unexpected phenomenon in all of physics. It is relative to everything. Here is a good link to read about it...hopefully it will explain.. http://www.intuitor.com/resonance/circuits.html Ever heard the term, "Dip the Plate" when tuning? Notice how the plate current drops but your output increases? Wonder why that is? Could it be your tank circuit has been tuned to resonance? Hmmm...your antenna is an extension of your tank circuit. And to K9IUQ...who wrote..."Also resonance of the SYSTEM has nothing to do with how well the antenna radiates. This is determined by MANY other factors. I have a wonderful Dummy load antenna under my desk that is resonant on all HF bands, however it doesnt seem to radiate very well since I haven't worked too many people with it."... I give up here, this guy just isn't with the program...A dummy LOAD is NOT resonate, it is a resistive LOAD designed to burn up the power by turning it into HEAT! Thats why they call it a dummy LOAD! (key word there is LOAD) Man..you guys say you want elmers, if you truely do not understand something, thats ok, there are people who do understand, and more than willing to help. 73 de W4LGH Alan http://www.w4lgh.com
Reply to a comment by : AA4PB on 2007-02-22

at resonance the antenna is inducing more power into the atmosphere ---------------------------------------------------- Can you point us to a definitive text that proves this, or even claims it to be true?
Reply to a comment by : K9IUQ on 2007-02-22

One TRUE statement was made, a RESONATE antenna will work BETTER than a NON_RESONATE antenna. People do NOT understand resonance ..................................................... The above is an false statement. An Antenna is resonant at ONLY ONE frequency. At any other frequency it is non-resonant. We all use non-resonant antennas (including you) on a daily basis. We make the antenna SYSTEM resonant with a tuner of one kind or another or live with SWR higher than 1:1. Agreed - the whole SYSTEM must be resonance -from the radio to the antenna. It makes little difference if the antenna itself is resonance or not.Many of the best performing wire antennas are non-resonant fed with open wire feeders and an antenna tuner. Also resonance of the SYSTEM has nothing to do with how well the antenna radiates. This is determined by MANY other factors. I have a wonderful Dummy load antenna under my desk that is resonant on all HF bands, however it doesnt seem to radiate very well since I haven't worked too many people with it. Please Pick Up an antenna Book like "Reflections" and learn the facts instead of trying to sell me 'some wonderful ocean front property in Arizona " K9IUQ
N3OX2007-02-22
RE: Benchmarks
Respectfully, W4LGH, I would like to point out that you are the one muddying the waters about a *resonant antenna* and its radiating effectiveness.

It is not true that antenna element resonance has anything to do with coupling power into the electromagnetic field around the antenna.

The *REAL* part of the antenna impedance has two components, the radiation resistance and the loss resistance. That fraction of the power which is associated with "dissipation" in the radiation resistance is the power that gets radiated. The fraction associated with dissipation in the loss resistance goes up as heat. The power in the reactive part of the impedance is simply stored in fields around the antenna.

That means that an antenna with an impedance of 70+j0 and one with an impedance of 70+j500 are radiating exactly the same amount of power if you can feed that power to them in the first place.

You need to match the antenna system to the transmitter but resonance of the antenna element itself has nothing at all to do with the transfer of that power to radiating electromagnetic fields.

If you are supplying 100W to the antenna, 100W minus the antenna losses is radiated, no matter whether or not the antenna element is resonant.

73,
Dan
Reply to a comment by : W4LGH on 2007-02-22

You see, here we go again, a good article is written, it contains some great info. Some additional articles are written taken it a little further. Then come the people who truely do not understand what is being said, and either go on what they have seen, or what somebody else who truely doesn't understand told them. ==================================================== Now... AA4PB writes..."at resonance the antenna is inducing more power into the atmosphere ---------------------------------------------------- Can you point us to a definitive text that proves this, or even claims it to be true?" ==================================================== Now with a call like this, this guy is at least an "ADVANCED" class if not an "EXTRA" class, what I said is basic "Physics 101" Resonance is a common thread which runs through almost every branch of physics, and yet a lot of people have never studied it. Without resonance we wouldn't have radio, television, music, or swings on playgrounds, not to mention cool gismos like Tesla coils. Of course, resonance also has its dark side. It occasionally causes a bridge to collapse, a helicopter to fly apart, or other inconveniences. Unlike black holes, time travel, and quantum mechanics, resonance is common place and easy to observe. Yet, it is one of the most striking and unexpected phenomenon in all of physics. It is relative to everything. Here is a good link to read about it...hopefully it will explain.. http://www.intuitor.com/resonance/circuits.html Ever heard the term, "Dip the Plate" when tuning? Notice how the plate current drops but your output increases? Wonder why that is? Could it be your tank circuit has been tuned to resonance? Hmmm...your antenna is an extension of your tank circuit. And to K9IUQ...who wrote..."Also resonance of the SYSTEM has nothing to do with how well the antenna radiates. This is determined by MANY other factors. I have a wonderful Dummy load antenna under my desk that is resonant on all HF bands, however it doesnt seem to radiate very well since I haven't worked too many people with it."... I give up here, this guy just isn't with the program...A dummy LOAD is NOT resonate, it is a resistive LOAD designed to burn up the power by turning it into HEAT! Thats why they call it a dummy LOAD! (key word there is LOAD) Man..you guys say you want elmers, if you truely do not understand something, thats ok, there are people who do understand, and more than willing to help. 73 de W4LGH Alan http://www.w4lgh.com
Reply to a comment by : AA4PB on 2007-02-22

at resonance the antenna is inducing more power into the atmosphere ---------------------------------------------------- Can you point us to a definitive text that proves this, or even claims it to be true?
Reply to a comment by : K9IUQ on 2007-02-22

One TRUE statement was made, a RESONATE antenna will work BETTER than a NON_RESONATE antenna. People do NOT understand resonance ..................................................... The above is an false statement. An Antenna is resonant at ONLY ONE frequency. At any other frequency it is non-resonant. We all use non-resonant antennas (including you) on a daily basis. We make the antenna SYSTEM resonant with a tuner of one kind or another or live with SWR higher than 1:1. Agreed - the whole SYSTEM must be resonance -from the radio to the antenna. It makes little difference if the antenna itself is resonance or not.Many of the best performing wire antennas are non-resonant fed with open wire feeders and an antenna tuner. Also resonance of the SYSTEM has nothing to do with how well the antenna radiates. This is determined by MANY other factors. I have a wonderful Dummy load antenna under my desk that is resonant on all HF bands, however it doesnt seem to radiate very well since I haven't worked too many people with it. Please Pick Up an antenna Book like "Reflections" and learn the facts instead of trying to sell me 'some wonderful ocean front property in Arizona " K9IUQ
K9IUQ2007-02-22
Benchmarks

To DON N4KC:
Thanx for saying what I couldnt quite get into words properly. You hit the nail squarely and it is obvious you read or studied some antenna books.

.........................................................
You also said:
But to take a wonderful antenna, like a full wavelength horizontal loop, and feed it with coax so you are only able to use it on or close to its resonant frequency is terrible waste of expensive copper. Feed it with ladder line and use a tuner to couple it to the 50-ohm out put of the radio and you can make use of that one long piece of nicely balanced wire on most every ham band.
.........................................................

I have one of these loops about 277 ft long. it is fed with open feeders and a TEN_TEC 238B Tuner. The antenna itself is NOT resonant in many places but I guarantee it radiates as well as any "resonant" dipole 10-75mtrs.

I also have a 130 ft wire fed with open feeders.Its mostly a non-resonant antenna that has been used since the infancy of ham history. Why? Because it works!

Alas there are far too many hams that are afraid of open wire feedline or worry that if my SWR aint 1:1 or if the antenna isnt resonant (AND fed with coax) it wont radiate. These are the same guys that run 1.5K with audio processing to make up for their lack of antenna knowledge.

K9IUQ

W4LGH2007-02-22
RE: Benchmarks
Don...I never said NOT to use a tuner, I simply said that you can NOT tune your antenna with a tuner in your shack being fed with un-balanced line. (Coax) Now balanced lines are a completely different story, and the feedline becomes part of the antenna. And as was pointed out, an antenna can be resonate on many freqs. know as harmonics, and as images. Harmonics are signals 2x 3x 4x etc higher than the fundamental freqs, and images are 1/2, 1/4, 1/8th etc of the fundamental freq. So this disproves that an antenna is only resonate on 1 frequency. You can also design an antenna to have broader bandwidths, by increasing the diameter of the radiatior or folding it back on itself.

You are right that I do enjoy operating vintage Drake equipment, and in one way one could call the tunable tank circuit an antenna tuner, but it really isn't. It is more a matching network for the hi-impedance of the tube outputs to match the low impedance of the antenna, so it is more of an antenna coupler than a tuner. This isn't needed with solid state outputs as they are already low-impedance and will match the low impedance of the antenna. remember you can feed low impedance into a hi-impedance, with a loss, but you can not feed hi impedance into a low impedance. And again, if my antennas were not resonate, tuning the tank circuit would NOT make it any better. The same hold true for you outboard antenna tuners. If you antenna is designed correctly you do not need it to match the output to the antenna.

Maybe if they had called it an antenna coupler, instead of antenna tuner...as the name implies it is doing something it is not.

Here is another interesting article about antenna resonance...and further explains why you have maximum current transfer with a resonate antenna....

http://www.intuitor.com/resonance/radioTVres.html

73 de W4LGH - Alan
http://www.w4lgh.com


Reply to a comment by : N4KC on 2007-02-22

Alan, W4LGH, your points are well taken but K9IUQ hit the nail on the head about "resonant" antennas and "antenna tuners." You say you don't use a "tuner," but I happen to know you enjoy using vintage Drake gear. In the output circuit of those transmitters were--you guessed it--an "antenna tuner!" Every one of those great old rigs had capacitors and inductors that you used to attempt to match the radio's output impedance to whatever antenna system they might encounter. With today's solid state rigs, we have simply moved that matching network out of the transmitter cabinet and onto the desktop. I'm with you when you say it is not a good idea to try to tune a 40 meter coax-fed dipole on 160. But if that is the only way you can get on 160 and you have a "matching unit" robust enough that it will make your transmitter happy without sending up smoke signals, have at it...without expecting to work much DX on the high band, of course. A "resonant antenna" is, as has been noted by K9IUQ and others, only resonant at one frequency and certain harmonics of that frequency, depending on design. Move at all in either direction from its "resonant" frequency and it is non-resonant. A tuner certainly helps extend the useability of a single band antenna, especially on the wider bands, and in most cases, the loss in a reasonably short run of good quality coax is something the operator can live with at HF frequencies, if he can just get his rig to accept the match. That sometimes takes some kind of matching device...internal tuner, outboard tuner, balun in the feedline somewhere, a bank of relays to switch in and out certain components. But to take a wonderful antenna, like a full wavelength horizontal loop, and feed it with coax so you are only able to use it on or close to its resonant frequency is a terrible waste of expensive copper. Feed it with ladder line and use a tuner to couple it to the 50-ohm out put of the radio and you can make use of that one long piece of nicely balanced wire on most every ham band. I think we see more antenna tuners for two reasons: -- Solid state rigs with little or limited ability to control the output impedance -- The desire to use fewer antennas and still have workable antennas on all HF bands, including the WARC bands. That's TEN bands, from 1.8 to 30 mHz! Maybe, if we continue to pursue more HF operating frequencies, we should all buy stock in MFJ, SGC, and Palstar! 73, Don N4KC www.donkeith.com
Reply to a comment by : AA4PB on 2007-02-22

at resonance the antenna is inducing more power into the atmosphere ---------------------------------------------------- Can you point us to a definitive text that proves this, or even claims it to be true?
Reply to a comment by : K9IUQ on 2007-02-22

One TRUE statement was made, a RESONATE antenna will work BETTER than a NON_RESONATE antenna. People do NOT understand resonance ..................................................... The above is an false statement. An Antenna is resonant at ONLY ONE frequency. At any other frequency it is non-resonant. We all use non-resonant antennas (including you) on a daily basis. We make the antenna SYSTEM resonant with a tuner of one kind or another or live with SWR higher than 1:1. Agreed - the whole SYSTEM must be resonance -from the radio to the antenna. It makes little difference if the antenna itself is resonance or not.Many of the best performing wire antennas are non-resonant fed with open wire feeders and an antenna tuner. Also resonance of the SYSTEM has nothing to do with how well the antenna radiates. This is determined by MANY other factors. I have a wonderful Dummy load antenna under my desk that is resonant on all HF bands, however it doesnt seem to radiate very well since I haven't worked too many people with it. Please Pick Up an antenna Book like "Reflections" and learn the facts instead of trying to sell me 'some wonderful ocean front property in Arizona " K9IUQ
N4KC2007-02-22
RE: Benchmarks
Alan, W4LGH, your points are well taken but K9IUQ hit the nail on the head about "resonant" antennas and "antenna tuners." You say you don't use a "tuner," but I happen to know you enjoy using vintage Drake gear. In the output circuit of those transmitters were--you guessed it--an "antenna tuner!" Every one of those great old rigs had capacitors and inductors that you used to attempt to match the radio's output impedance to whatever antenna system they might encounter.

With today's solid state rigs, we have simply moved that matching network out of the transmitter cabinet and onto the desktop. I'm with you when you say it is not a good idea to try to tune a 40 meter coax-fed dipole on 160. But if that is the only way you can get on 160 and you have a "matching unit" robust enough that it will make your transmitter happy without sending up smoke signals, have at it...without expecting to work much DX on the high band, of course.

A "resonant antenna" is, as has been noted by K9IUQ and others, only resonant at one frequency and certain harmonics of that frequency, depending on design. Move at all in either direction from its "resonant" frequency and it is non-resonant. A tuner certainly helps extend the useability of a single band antenna, especially on the wider bands, and in most cases, the loss in a reasonably short run of good quality coax is something the operator can live with at HF frequencies, if he can just get his rig to accept the match. That sometimes takes some kind of matching device...internal tuner, outboard tuner, balun in the feedline somewhere, a bank of relays to switch in and out certain components.

But to take a wonderful antenna, like a full wavelength horizontal loop, and feed it with coax so you are only able to use it on or close to its resonant frequency is a terrible waste of expensive copper. Feed it with ladder line and use a tuner to couple it to the 50-ohm out put of the radio and you can make use of that one long piece of nicely balanced wire on most every ham band.

I think we see more antenna tuners for two reasons:
-- Solid state rigs with little or limited ability to control the output impedance
-- The desire to use fewer antennas and still have workable antennas on all HF bands, including the WARC bands. That's TEN bands, from 1.8 to 30 mHz!

Maybe, if we continue to pursue more HF operating frequencies, we should all buy stock in MFJ, SGC, and Palstar!

73,

Don N4KC
www.donkeith.com
Reply to a comment by : AA4PB on 2007-02-22

at resonance the antenna is inducing more power into the atmosphere ---------------------------------------------------- Can you point us to a definitive text that proves this, or even claims it to be true?
Reply to a comment by : K9IUQ on 2007-02-22

One TRUE statement was made, a RESONATE antenna will work BETTER than a NON_RESONATE antenna. People do NOT understand resonance ..................................................... The above is an false statement. An Antenna is resonant at ONLY ONE frequency. At any other frequency it is non-resonant. We all use non-resonant antennas (including you) on a daily basis. We make the antenna SYSTEM resonant with a tuner of one kind or another or live with SWR higher than 1:1. Agreed - the whole SYSTEM must be resonance -from the radio to the antenna. It makes little difference if the antenna itself is resonance or not.Many of the best performing wire antennas are non-resonant fed with open wire feeders and an antenna tuner. Also resonance of the SYSTEM has nothing to do with how well the antenna radiates. This is determined by MANY other factors. I have a wonderful Dummy load antenna under my desk that is resonant on all HF bands, however it doesnt seem to radiate very well since I haven't worked too many people with it. Please Pick Up an antenna Book like "Reflections" and learn the facts instead of trying to sell me 'some wonderful ocean front property in Arizona " K9IUQ
KX0R2007-02-22
Benchmarks

I liked most of Alan's post here - especially the key point that we need to pay attention to what we compare to, our benchmarks, when we evaluate antennas. There is a lot of selective thinking and advertising with respect to antennas. All our antennas are compromises between what we wish we had and what we can actually erect, so we want to feel good about that we have.

I think the criticism of tuners and tuner-based antenna systems is too negative, although many of the points are valid. Alan's points about the problems of the stressed T network are right on. However, tuners can multiply your station's capabilities.

Consider this: When measured against the major benchmarks of money and time spent, a dipole or two, or loops, fed with open line and tuners, may deliver more performance on more bands than many of the more sophisticated narrowband systems. A dipole and its relatives will perform well on several bands, and then they can be fed against ground as a T-antenna or inverted-L on lower frequencies. You do need a tuner, or maybe several, to get the most out of a simple antenna system.

Another key point that Alan's article misses: benchmarks are important, but they are usually comparisons of the best features of a system. With a real antenna system, on the air, what often matters concerns the limiting features of the system. For example, a yagi on a tower may have excellent performance in its favored azimuth direction or vertical wave angle, but this comes at the expense of poorer performance in other directions. If you're calling CQ or even working a contest, the yagi may not raise some stations that a dipole or vertical would bring in better, unless it’s pointed correctly at the critical moment.

With any antenna, it's the nulls that kill you. Take a QRP rig out for Field Day, put up a dipole, and you'll learn real quick about being heard. You'll work lots of stations for sure, but the ones in your null directions will be harder to hear and work. The easy fix is to put up another dipole, perhaps at right angles to the first one. Then you need another feedline and probably another tuner, plus a switch in the 50-ohm line to the rig. Once you actually use one of these A-B switches, your view of antennas will be forever clearer - you'll hear many stations that are easy copy on one antenna, but in the noise on the other! You'd never know what you're missing without the switched pair. I use the same concept at home, and it's amazing how many QSO's I've made because I had two or three antennas available. In contests, when DX is coming in from several direcions, like on 20 meters at noon, just having a switched pair of antennas is magic. If you want a lot of bang for your time and money, just put up a pair of vertically-oriented, horizontally-polarized loops on one mast, at right angles in azimuth, use some kind of fast-switching scheme, and you'll have a system that can work 4 or 5 HF bands, with nice results. No, you won't come close to the yagi plus tower gain benchmarks, but you'll do real well on your Q's per dollar. Likewise, if you're now using a vertical as your primary system, you should consider adding a loop or a dipole, another tuner, and an A-B switch, so you can make some comparisons. It's really important to have references and make comparisons between your antennas.

In my experience, resonance is usually one of the least important variables in a multiband antenna. Resonance just means that we have an impedance R+jX where X is a very small number compared to R. There are so many ways to correct the jX term with a network or another component, that resonance is usually a minor concern compared to all the other constraints we may have. Resonance is critical when we're concerned with the dimensions of a parasitic element in a yagi, or any time we’re concerned with phasing. We do have to understand resonance and how to correct impedances to 50 ohms, if we have a rig that needs to see 50 ohms in order to perform best. That doesn't mean our antenna should be resonant.

The game is transforming complex impedances to 50 ohms while minimizing losses. If we can do that at many frequencies, we can get a lot more performance from whatever we can put up. This is not a subject with easy answers or simple rules, which is why there is so much misinformation and confusion. Read the books and learn – it may take a long time to get deep enough.

To the person who said that he runs QRP rigs into 3:1 SWR's, yes you made contacts that way, but many QRP rigs have very simple transmitters designed to see 50 ohms resistive, and many of them will actually become unstable into a moderate mismatch! This means you may be radiating extra signals, parasitics, outside the ham bands, totally illegal and not cool. Even my sweet little KX1 misbehaves at 2:1 if the load is reactive! A tuner or matched antenna can keep you legal, and it will maximize the power delivered by your simple transmitter; plus it may save your final(s) from destruction.

Maybe the hardest choice is deciding which benchmarks are important for our antennas – and too often the choices are determined by covenants or what we can get away with where we live.
W4LGH2007-02-22
RE: Benchmarks
You see, here we go again, a good article is written, it contains some great info. Some additional articles are written taken it a little further. Then come the people who truely do not understand what is being said, and either go on what they have seen, or what somebody else who truely doesn't understand told them.
====================================================
Now... AA4PB writes..."at resonance the antenna is inducing more power into the atmosphere
----------------------------------------------------
Can you point us to a definitive text that proves this, or even claims it to be true?"
====================================================

Now with a call like this, this guy is at least an "ADVANCED" class if not an "EXTRA" class, what I said is basic "Physics 101" Resonance is a common thread which runs through almost every branch of physics, and yet a lot of people have never studied it. Without resonance we wouldn't have radio, television, music, or swings on playgrounds, not to mention cool gismos like Tesla coils. Of course, resonance also has its dark side. It occasionally causes a bridge to collapse, a helicopter to fly apart, or other inconveniences. Unlike black holes, time travel, and quantum mechanics, resonance is common place and easy to observe. Yet, it is one of the most striking and unexpected phenomenon in all of physics. It is relative to everything.

Here is a good link to read about it...hopefully it will explain..

http://www.intuitor.com/resonance/circuits.html

Ever heard the term, "Dip the Plate" when tuning? Notice how the plate current drops but your output increases? Wonder why that is? Could it be your tank circuit has been tuned to resonance? Hmmm...your antenna is an extension of your tank circuit.

And to K9IUQ...who wrote..."Also resonance of the SYSTEM has nothing to do with how well the antenna radiates. This is determined by MANY other factors. I have a wonderful Dummy load antenna under my desk that is resonant on all HF bands, however it doesnt seem to radiate very well since I haven't worked too many people with it."...

I give up here, this guy just isn't with the program...A dummy LOAD is NOT resonate, it is a resistive LOAD designed to burn up the power by turning it into HEAT! Thats why they call it a dummy LOAD! (key word there is LOAD)

Man..you guys say you want elmers, if you truely do not understand something, thats ok, there are people who do understand, and more than willing to help.

73 de W4LGH Alan
http://www.w4lgh.com

Reply to a comment by : AA4PB on 2007-02-22

at resonance the antenna is inducing more power into the atmosphere ---------------------------------------------------- Can you point us to a definitive text that proves this, or even claims it to be true?
Reply to a comment by : K9IUQ on 2007-02-22

One TRUE statement was made, a RESONATE antenna will work BETTER than a NON_RESONATE antenna. People do NOT understand resonance ..................................................... The above is an false statement. An Antenna is resonant at ONLY ONE frequency. At any other frequency it is non-resonant. We all use non-resonant antennas (including you) on a daily basis. We make the antenna SYSTEM resonant with a tuner of one kind or another or live with SWR higher than 1:1. Agreed - the whole SYSTEM must be resonance -from the radio to the antenna. It makes little difference if the antenna itself is resonance or not.Many of the best performing wire antennas are non-resonant fed with open wire feeders and an antenna tuner. Also resonance of the SYSTEM has nothing to do with how well the antenna radiates. This is determined by MANY other factors. I have a wonderful Dummy load antenna under my desk that is resonant on all HF bands, however it doesnt seem to radiate very well since I haven't worked too many people with it. Please Pick Up an antenna Book like "Reflections" and learn the facts instead of trying to sell me 'some wonderful ocean front property in Arizona " K9IUQ
WB2WIK2007-02-22
RE: Benchmarks
>RE: Benchmarks Reply
by WB2WIK on February 22, 2007 Mail this to a friend!


>::This isn't true, at all. An antenna is resonant anywhere it provides a resistive load without reactance. That occurs at a number of frequencies, typically the fundamental and all harmonics of that fundamental (both odd and even). There's also a resonance bandwidth for antennas, because antennas have some resistance. Antennas aren't piezoelectric crystals that have a "Q" of several thousand. Most antennas have a matched bandwidth (resonance) that covers about 1/5%<

::Oops, I should proof my own stuff! I meant "1%" not 1/5%, which makes no sense.

WB2WIK/6
Reply to a comment by : WB2WIK on 2007-02-22

Benchmarks Reply by K9IUQ on February 22, 2007 Mail this to a friend! An Antenna is resonant at ONLY ONE frequency. At any other frequency it is non-resonant.< ::This isn't true, at all. An antenna is resonant anywhere it provides a resistive load without reactance. That occurs at a number of frequencies, typically the fundamental and all harmonics of that fundamental (both odd and even). There's also a resonance bandwidth for antennas, because antennas have some resistance. Antennas aren't piezoelectric crystals that have a "Q" of several thousand. Most antennas have a matched bandwidth (resonance) that covers about 1/5% of the actual operating frequency. On 20 meters, that would be 200 kHz, which is more than half the band, where a typical "full sized" (e.g., 1/2-wavelength dipole) antenna presents a nearly pure resistive load. That's resonance. That same 1/2-wave dipole (example) is also resonant at 2x, 3x, 4x, 5x etc. harmonics. WB2WIK/6
Reply to a comment by : K9IUQ on 2007-02-22

One TRUE statement was made, a RESONATE antenna will work BETTER than a NON_RESONATE antenna. People do NOT understand resonance ..................................................... The above is an false statement. An Antenna is resonant at ONLY ONE frequency. At any other frequency it is non-resonant. We all use non-resonant antennas (including you) on a daily basis. We make the antenna SYSTEM resonant with a tuner of one kind or another or live with SWR higher than 1:1. Agreed - the whole SYSTEM must be resonance -from the radio to the antenna. It makes little difference if the antenna itself is resonance or not.Many of the best performing wire antennas are non-resonant fed with open wire feeders and an antenna tuner. Also resonance of the SYSTEM has nothing to do with how well the antenna radiates. This is determined by MANY other factors. I have a wonderful Dummy load antenna under my desk that is resonant on all HF bands, however it doesnt seem to radiate very well since I haven't worked too many people with it. Please Pick Up an antenna Book like "Reflections" and learn the facts instead of trying to sell me 'some wonderful ocean front property in Arizona " K9IUQ
WB2WIK2007-02-22
RE: Benchmarks
Benchmarks Reply
by K9IUQ on February 22, 2007 Mail this to a friend!
An Antenna is resonant at ONLY ONE frequency. At any other frequency it is non-resonant.<

::This isn't true, at all. An antenna is resonant anywhere it provides a resistive load without reactance. That occurs at a number of frequencies, typically the fundamental and all harmonics of that fundamental (both odd and even). There's also a resonance bandwidth for antennas, because antennas have some resistance. Antennas aren't piezoelectric crystals that have a "Q" of several thousand. Most antennas have a matched bandwidth (resonance) that covers about 1/5% of the actual operating frequency. On 20 meters, that would be 200 kHz, which is more than half the band, where a typical "full sized" (e.g., 1/2-wavelength dipole) antenna presents a nearly pure resistive load. That's resonance.

That same 1/2-wave dipole (example) is also resonant at 2x, 3x, 4x, 5x etc. harmonics.

WB2WIK/6
Reply to a comment by : K9IUQ on 2007-02-22

One TRUE statement was made, a RESONATE antenna will work BETTER than a NON_RESONATE antenna. People do NOT understand resonance ..................................................... The above is an false statement. An Antenna is resonant at ONLY ONE frequency. At any other frequency it is non-resonant. We all use non-resonant antennas (including you) on a daily basis. We make the antenna SYSTEM resonant with a tuner of one kind or another or live with SWR higher than 1:1. Agreed - the whole SYSTEM must be resonance -from the radio to the antenna. It makes little difference if the antenna itself is resonance or not.Many of the best performing wire antennas are non-resonant fed with open wire feeders and an antenna tuner. Also resonance of the SYSTEM has nothing to do with how well the antenna radiates. This is determined by MANY other factors. I have a wonderful Dummy load antenna under my desk that is resonant on all HF bands, however it doesnt seem to radiate very well since I haven't worked too many people with it. Please Pick Up an antenna Book like "Reflections" and learn the facts instead of trying to sell me 'some wonderful ocean front property in Arizona " K9IUQ
AA4PB2007-02-22
RE: Benchmarks
Being reciprocal means that the gain and pattern are the same on Rx as they are on Tx.
Reply to a comment by : AA4PB on 2007-02-22

The fact that antennas are reciprocal on Rx and Tx may or may not be irrelevant, depending on what you are doing. Certainly on the lower bands where noise levels are high you will find some antennas perform better on receive because they pick up less noise. Perform better means that you are able to copy signals better with them. Being reciprocal means that the gain and pattern are the same on Rx as they are on Rx. Whether it is relevant or not, antennas are always reciprocal.
Reply to a comment by : AA4PB on 2007-02-22

at resonance the antenna is inducing more power into the atmosphere ---------------------------------------------------- Can you point us to a definitive text that proves this, or even claims it to be true?
Reply to a comment by : K9IUQ on 2007-02-22

One TRUE statement was made, a RESONATE antenna will work BETTER than a NON_RESONATE antenna. People do NOT understand resonance ..................................................... The above is an false statement. An Antenna is resonant at ONLY ONE frequency. At any other frequency it is non-resonant. We all use non-resonant antennas (including you) on a daily basis. We make the antenna SYSTEM resonant with a tuner of one kind or another or live with SWR higher than 1:1. Agreed - the whole SYSTEM must be resonance -from the radio to the antenna. It makes little difference if the antenna itself is resonance or not.Many of the best performing wire antennas are non-resonant fed with open wire feeders and an antenna tuner. Also resonance of the SYSTEM has nothing to do with how well the antenna radiates. This is determined by MANY other factors. I have a wonderful Dummy load antenna under my desk that is resonant on all HF bands, however it doesnt seem to radiate very well since I haven't worked too many people with it. Please Pick Up an antenna Book like "Reflections" and learn the facts instead of trying to sell me 'some wonderful ocean front property in Arizona " K9IUQ
AA4PB2007-02-22
RE: Benchmarks
The fact that antennas are reciprocal on Rx and Tx may or may not be irrelevant, depending on what you are doing. Certainly on the lower bands where noise levels are high you will find some antennas perform better on receive because they pick up less noise. Perform better means that you are able to copy signals better with them. Being reciprocal means that the gain and pattern are the same on Rx as they are on Rx.

Whether it is relevant or not, antennas are always reciprocal.
Reply to a comment by : AA4PB on 2007-02-22

at resonance the antenna is inducing more power into the atmosphere ---------------------------------------------------- Can you point us to a definitive text that proves this, or even claims it to be true?
Reply to a comment by : K9IUQ on 2007-02-22

One TRUE statement was made, a RESONATE antenna will work BETTER than a NON_RESONATE antenna. People do NOT understand resonance ..................................................... The above is an false statement. An Antenna is resonant at ONLY ONE frequency. At any other frequency it is non-resonant. We all use non-resonant antennas (including you) on a daily basis. We make the antenna SYSTEM resonant with a tuner of one kind or another or live with SWR higher than 1:1. Agreed - the whole SYSTEM must be resonance -from the radio to the antenna. It makes little difference if the antenna itself is resonance or not.Many of the best performing wire antennas are non-resonant fed with open wire feeders and an antenna tuner. Also resonance of the SYSTEM has nothing to do with how well the antenna radiates. This is determined by MANY other factors. I have a wonderful Dummy load antenna under my desk that is resonant on all HF bands, however it doesnt seem to radiate very well since I haven't worked too many people with it. Please Pick Up an antenna Book like "Reflections" and learn the facts instead of trying to sell me 'some wonderful ocean front property in Arizona " K9IUQ
AA4PB2007-02-22
RE: Benchmarks
at resonance the antenna is inducing more power into the atmosphere
----------------------------------------------------
Can you point us to a definitive text that proves this, or even claims it to be true?
Reply to a comment by : K9IUQ on 2007-02-22

One TRUE statement was made, a RESONATE antenna will work BETTER than a NON_RESONATE antenna. People do NOT understand resonance ..................................................... The above is an false statement. An Antenna is resonant at ONLY ONE frequency. At any other frequency it is non-resonant. We all use non-resonant antennas (including you) on a daily basis. We make the antenna SYSTEM resonant with a tuner of one kind or another or live with SWR higher than 1:1. Agreed - the whole SYSTEM must be resonance -from the radio to the antenna. It makes little difference if the antenna itself is resonance or not.Many of the best performing wire antennas are non-resonant fed with open wire feeders and an antenna tuner. Also resonance of the SYSTEM has nothing to do with how well the antenna radiates. This is determined by MANY other factors. I have a wonderful Dummy load antenna under my desk that is resonant on all HF bands, however it doesnt seem to radiate very well since I haven't worked too many people with it. Please Pick Up an antenna Book like "Reflections" and learn the facts instead of trying to sell me 'some wonderful ocean front property in Arizona " K9IUQ
K9IUQ2007-02-22
Benchmarks
One TRUE statement was made, a RESONATE antenna will work BETTER than a NON_RESONATE antenna. People do NOT understand resonance
.....................................................

The above is an false statement.


An Antenna is resonant at ONLY ONE frequency. At any other frequency it is non-resonant. We all use non-resonant antennas (including you) on a daily basis. We make the antenna SYSTEM resonant with a tuner of one kind or another or live with SWR higher than 1:1.

Agreed - the whole SYSTEM must be resonance -from the radio to the antenna. It makes little difference if the antenna itself is resonance or not.Many of the best performing wire antennas are non-resonant fed with open wire feeders and an antenna tuner.

Also resonance of the SYSTEM has nothing to do with how well the antenna radiates. This is determined by MANY other factors. I have a wonderful Dummy load antenna under my desk that is resonant on all HF bands, however it doesnt seem to radiate very well since I haven't worked too many people with it.

Please Pick Up an antenna Book like "Reflections" and learn the facts instead of trying to sell me 'some wonderful ocean front property in Arizona "

K9IUQ


WB2WIK2007-02-22
RE: Benchmarks
I didn't read all the comments but think this is a good, thought-provoking article.

What I know for sure Alan intended and didn't directly mention is that you can't really judge an antenna's performance unless you have another antenna to compare it to. Or two. Or three. Or ten.

While W9PMZ has a good point about antenna *radiation pattern* being reciprocal for transmitting and receiving, this is another theory that lacks real-world relevance when applied to the HF bands. It starts to become seriously usable at VHF, UHF, SHF, EHF and above, where noise levels are low. On HF, I have Beverage antennas that provide 30 dB S+N/N on signals that cannot even be heard with my transmitting vertical antenna, but if I use those same Beverage antennas to transmit, nobody hears me. Reciprocal? Technically, yes. Operationally, not even close.

If a station lacks resources to install multiple antennas for a band of operation, find a nearby neighbor to compare with. I try to do both (have multiple antennas for each band, *and* compare what I can work at a given moment with close by neighbors on the band at that same moment, by inviting them into the contact). "Nearby" for HF (ionospheric paths) might be another station within 10-20-30 miles, they don't need to be next door. It's very revealing.

WB2WIK/6
Reply to a comment by : K8TDJ on 2007-02-22

Good, thought-provoking article Alan. The reciprocity argument aside for a moment, I am reminded when I decided to elevate my Butternut HF-6V to 40' and put 8 elevated radials around it, to approach a ground-mounted, full size vertical with 120 radials in efficiency. My ham friends thought I was nuts, but, given my situation, I had to do the best possible compared to the ideal benchmark; As you said, benchmarks are necessary to understand what performance truly is! And now, to get more folks to understand ham radio benchmarks!!73, Jim K8TDJ
Reply to a comment by : K9IUQ on 2007-02-22

I forgot to comment about this one - it is such a stupid comment it is beyond an un-truth. ..................................................... The idea of an antenna tuner hooked to an un-balanced line (coax) is absurd ..................................................... If this was true we wouldn't have built-in antenna tuners in our rigs. Every solidstate radio I have ever owned started shutting down power at a 1.5 swr. What happens with your wonderful 75mtr resonant antenna when you move 50 khz off your resonant frequency? Oh you are one of those guys that own a 75 mtr freq and never move. Gess you dont need a tuner then.... Of course if you are one of those fellows you have a 1.5kw AMP. Gess what that amp has - a pi-network. Think it does any antenna tuning? K9IUQ
N0AH2007-02-22
Benchmarks
There are just to many factors to compare antenna benchmarks in a realistic manner that some have suggested. Here is an example.

Back in 1998, I was using an AEA Isoloop antenna. It had a large tunable capacitor (the size of a football) in ther center surrounded by a flexible soft metal ribbon. (About 3 feet)

The antenna had a very narrow bandwidth and a high Q. Effcient right? I worked over 150 countries in two years, efficient, right? I got great signal reports! So on the surface, great antenna- not.

Because of the nature of the hgh Q, outdoor temperatures and wx conditions could cause the 10-20M loop resonance to go whacko. This n mid QSO. Setting the loop's resonant point point back using the variable tuner on the capacitor was a nightmare.

And worse, running more that 100Watts was "deadly" if the casing on the capacitor was removed and you touched it.

Oter than this, the AEA Isoloop was ok...but not an antenna to use a bench mark one day to check on it the next.

I can say the same for all of the antennas I have built over the years. I don't look at bench marks, I just look at keeping them up in the air and transmitting.
K8TDJ2007-02-22
RE: Benchmarks
Good, thought-provoking article Alan. The reciprocity argument aside for a moment, I am reminded when I decided to elevate my Butternut HF-6V to 40' and put 8 elevated radials around it, to approach a ground-mounted, full size vertical with 120 radials in efficiency. My ham friends thought I was nuts, but, given my situation, I had to do the best possible compared to the ideal benchmark; As you said, benchmarks are necessary to understand what performance truly is! And now, to get more folks to understand ham radio benchmarks!!73, Jim K8TDJ
Reply to a comment by : K9IUQ on 2007-02-22

I forgot to comment about this one - it is such a stupid comment it is beyond an un-truth. ..................................................... The idea of an antenna tuner hooked to an un-balanced line (coax) is absurd ..................................................... If this was true we wouldn't have built-in antenna tuners in our rigs. Every solidstate radio I have ever owned started shutting down power at a 1.5 swr. What happens with your wonderful 75mtr resonant antenna when you move 50 khz off your resonant frequency? Oh you are one of those guys that own a 75 mtr freq and never move. Gess you dont need a tuner then.... Of course if you are one of those fellows you have a 1.5kw AMP. Gess what that amp has - a pi-network. Think it does any antenna tuning? K9IUQ
W4LGH2007-02-22
RE: Benchmarks
K9IUQ worte..~"I forgot to comment about this one - it is such a stupid comment it is beyond an un-truth.
.....................................................
The idea of an antenna tuner hooked to an un-balanced line (coax) is absurd
.....................................................
If this was true we wouldn't have built-in antenna tuners in our rigs."~ END:
=====================================================
My response...
I could explain WHY your solid-state rig has a built in antenna tuner, but I am NOT going there, instead..
I have some wonderful ocean front property in Arizona that I want to sell you really CHEAP! And I'll even finance it to you! If you call right now, I'll double this offer...2 acres for the price of one! But you have to call in the next 10 minutes, have your CREDIT CARD READY!

I guess those infomercials really work!
Pay NO attention to the man behind the curtain.

73 de W4LGH - Alan
http://www.w4lgh.com

Reply to a comment by : K9IUQ on 2007-02-22

I forgot to comment about this one - it is such a stupid comment it is beyond an un-truth. ..................................................... The idea of an antenna tuner hooked to an un-balanced line (coax) is absurd ..................................................... If this was true we wouldn't have built-in antenna tuners in our rigs. Every solidstate radio I have ever owned started shutting down power at a 1.5 swr. What happens with your wonderful 75mtr resonant antenna when you move 50 khz off your resonant frequency? Oh you are one of those guys that own a 75 mtr freq and never move. Gess you dont need a tuner then.... Of course if you are one of those fellows you have a 1.5kw AMP. Gess what that amp has - a pi-network. Think it does any antenna tuning? K9IUQ
W4LGH2007-02-22
RE: Benchmarks
Everybody has their own opinions on what works for them and why. And I am certainly NOT going to argue with anyone who says something works for them, as you can explain until you are BLUE in the face, and they will never understand.

One TRUE statement was made, a RESONATE antenna will work BETTER than a NON_RESONATE antenna. People do NOT understand resonance, nor the face that at resonance the antenna is inducing more power into the atmosphere, just like a bell ring, an tank circuit, or singing in the shower, when you hit that one note that is 10X louder than the others. Your antenna is doing the same thing.

To the person who said loading a 75m antenna on 20m with a tuner...I didn't say it would work, I said it WON'T work effeciently, and the idea of trying to tune a piece of coax is STILL ABSURD!!

Trapped antennas was discussed, and stated as BAD. Trapped antennas can be VERY GOOD, with min problems, if the traps are designed and built correctly. Again, someone doesn't understand resonance.

Makes no difference to me what you use, how you use it, or why. People keep saying no one elmers, and when a good elmer article hits here, instead of listening to it, everyone wants to argue thats not how it works for them!

There are a few Hams out there that DO understand whats really happening, and why. A lot can be learned from them. As it was said "antenna science" is NOT new, its all been tried and documented many times over. Just because some big manufacture makes it and says it works, doesn't make it so. They are only trying to GET your MONEY! I could name a dozen commercial antennas out there that aren't worth a damn, and a low SWR is only PART of the equation!

Impedance matching and resonance and very important, as well apature,& take off angle.


73 de W4LGH - Alan
http://www.w4lgh.com
Reply to a comment by : WY3X on 2007-02-22

>W9PMZ : "antennas are NOT reciprocal in their transmit >verses receive performance" Rewriting text books? I cannot count the number of times on Field Day where I heard a station with S9+ signal strengths, and repeatedly went back to them without being heard. These stations continued to call CQ, occasionally receiving a signal report from stations I was not hearing, but mostly, just calling CQ and not hearing me AT ALL! There's your proof- reciprocal signals are not embedded in reality. I don't necessarily subscribe to the theory that the problem is antenna-induced, it could simply be conditions are one-way. The point is, it happens. -KR4WM
Reply to a comment by : W9PMZ on 2007-02-22

"antennas are NOT reciprocal in their transmit verses receive performance" Rewriting text books? Most antenna books that I have been privy to read starts the treatment of antennas by making a statement: "In this section we show that the radiation pattern of an antenna is the same whether it is used as a transmitting antenna or a receiving antenna. Reciprocity allows the calculation or measurement of an antenna pattern in either the transmit or receive case." (from Antenna Theory and Design by Stutzman and Thiele, page 40) Propagation at HF makes the antennas properties (height, length, etc) the issue, but the antenna still obeys reciprocity. 73, Carl - W9PMZ
Reply to a comment by : ONAIR on 2007-02-22

Interesting point. So a resonant vertical dipole would then be a lot more efficient than a vertical that you would need to tune?
W9PMZ2007-02-22
RE: Benchmarks
"KR4WM - I cannot count the number of times on Field Day where I heard a station with S9+ signal strengths, and repeatedly went back to them without being heard. These stations continued to call CQ, occasionally receiving a signal report from stations I was not hearing, but mostly, just calling CQ and not hearing me AT ALL! There's your proof- reciprocal signals are not embedded in reality. "

You can only make the judgement about your antenna. You know nothing about the other stations antenna. He maybe using a vertical on transmit and a beam on receive. You just don't know.

But he maybe ignoring you because you are a dupe.....

73,

Carl - W9PMZ
Reply to a comment by : K9IUQ on 2007-02-22

I forgot to comment about this one - it is such a stupid comment it is beyond an un-truth. ..................................................... The idea of an antenna tuner hooked to an un-balanced line (coax) is absurd ..................................................... If this was true we wouldn't have built-in antenna tuners in our rigs. Every solidstate radio I have ever owned started shutting down power at a 1.5 swr. What happens with your wonderful 75mtr resonant antenna when you move 50 khz off your resonant frequency? Oh you are one of those guys that own a 75 mtr freq and never move. Gess you dont need a tuner then.... Of course if you are one of those fellows you have a 1.5kw AMP. Gess what that amp has - a pi-network. Think it does any antenna tuning? K9IUQ
K9IUQ2007-02-22
Benchmarks
I forgot to comment about this one - it is such a stupid comment it is beyond an un-truth.

.....................................................
The idea of an antenna tuner hooked to an un-balanced line (coax) is absurd
.....................................................

If this was true we wouldn't have built-in antenna tuners in our rigs. Every solidstate radio I have ever owned started shutting down power at a 1.5 swr. What happens with your wonderful 75mtr resonant antenna when you move 50 khz off your resonant frequency? Oh you are one of those guys that own a 75 mtr freq and never move. Gess you dont need a tuner then.... Of course if you are one of those fellows you have a 1.5kw AMP. Gess what that amp has - a pi-network. Think it does any antenna tuning?

K9IUQ
WY3X2007-02-22
RE: Benchmarks
>W9PMZ : "antennas are NOT reciprocal in their transmit >verses receive performance" Rewriting text books?

I cannot count the number of times on Field Day where I heard a station with S9+ signal strengths, and repeatedly went back to them without being heard. These stations continued to call CQ, occasionally receiving a signal report from stations I was not hearing, but mostly, just calling CQ and not hearing me AT ALL! There's your proof- reciprocal signals are not embedded in reality.

I don't necessarily subscribe to the theory that the problem is antenna-induced, it could simply be conditions are one-way. The point is, it happens.

-KR4WM
Reply to a comment by : W9PMZ on 2007-02-22

"antennas are NOT reciprocal in their transmit verses receive performance" Rewriting text books? Most antenna books that I have been privy to read starts the treatment of antennas by making a statement: "In this section we show that the radiation pattern of an antenna is the same whether it is used as a transmitting antenna or a receiving antenna. Reciprocity allows the calculation or measurement of an antenna pattern in either the transmit or receive case." (from Antenna Theory and Design by Stutzman and Thiele, page 40) Propagation at HF makes the antennas properties (height, length, etc) the issue, but the antenna still obeys reciprocity. 73, Carl - W9PMZ
Reply to a comment by : ONAIR on 2007-02-22

Interesting point. So a resonant vertical dipole would then be a lot more efficient than a vertical that you would need to tune?
K9IUQ2007-02-22
Benchmarks
Antenna Discussions like this always show me how little Hams know about antennas. The same un-truths I hear on the air show up in print. If hams would only READ the antenna literature available the untruths would not persist.Some out right lies:


Non-resonant antennas dont work as well as reasonant antennas. - - - How well an antenna performs has NOTHING to do with resonancy.

A SWR of 3:1 is going to lose 25% of your power. - This guy needs to read the well respected book "Reflections" by Walter Maxell. On page 1-5 there is a wonderful chart that all hams should have on their wall. It shows loss in db according to SWR. This chart and excerpts from the book was recently reprinted in QST. Maxwell CLEARLY states a SWR (with good coax) as high as 5:1 will have an imperceptible difference on the receiving end vs a 1:1 swr.

After 46 years of listening to and reading online about Antennas, I have concluded that most Hams know Little Antenna theory. It aint Voo-doo or magic fellows, antenna perfomance and theory has been well established. we only have to get our information from respected books - NOT other Hams or eham discussions.

K9IUQ





N3OX2007-02-22
RE: Benchmarks
"I feel that these kinds of articles can scare folks away from trying something that might be "less than optimal". They keep people off the air (especially HF) because they don't have the facilities or inclination to put up the "perfect, textbook antenna". That somehow those of us who have compromise systems should not bother to even go on the air."

No way. Most hams on HF are using compromise antennas; that is, they're not using the best antenna they could possibly imagine wanting.

This article won't keep anyone off of HF. I think the problem is just the opposite. Many people get on HF with a compromise antenna and they don't understand the compromises. Then they work some good DX and don't understand that the antenna isn't more of a compromise than it has to be.

They make an unnecessary compromise like using a tuner in the shack to get their coax-fed 40m dipole on 20m instead of adding $3 of wire in the form of 20m legs. Then they go and recommend this bad antenna to their friends, because it works. Manufacturers supply tuners that have three coax jacks and one junky balun output instead of three balanced outputs with a decent balun.

I think it's important to make EDUCATED compromises with your compromise antenna. If you do it right you could pick up 10dB or more over someone who's doing it wrong.

Compromise, to me, means doing the best you can within the constraints of your time, your space, and your budget. It doesn't mean using a crappy antenna system because you didn't do any of your homework.

73,
Dan
Reply to a comment by : N3OX on 2007-02-22

"I have always believed that antennas TEND to function in a reciprocal manner with respect to receiving and transmitting, but I'd like to hear more from the technical gurus out there. " Antennas are completely reciprocal as far as the electromagnetic fields are concerned. If they weren't, the technique I use for field strength measurements would not work*. However, because the noise floor on the HF bands can be set by noise outside the RX, and usually is, it's possible for you to transmit a signal that a station in a quieter location can hear, but when they reply at the same power level with the same path loss and the same antennas, you can't hear them. The antennas are electromagnetically reciprocal devices, but yours is picking up additional signals that mask the desired one, so the communication path is not reciprocal. - - - - - - *this footnote is regarding ensuring that your RX-based FS measurements are reciprocal. your RX is probably not 50 ohm input impedance; I understand that it's often quite high. If you want to ensure that your antenna and RX *system* is reciprocal for field strength measurement purposes, you need to terminate the RX end of the cable in 50 ohms. Switching in ~20dB of attenuation as a minimum will do this. 73, Dan
Reply to a comment by : N3OX on 2007-02-22

"Interesting point. So a resonant vertical dipole would then be a lot more efficient than a vertical that you would need to tune?" It entirely depends on where you put the tuner. I use a 60 foot vertical (which is, admittedly resonant on 3600kHz) on 160m, 80m, 40m, and 30m with good results. My tuner is homebrew and at the base of the antenna: http://www.n3ox.net/projects/sixtyvert I did the same thing with a 40 foot vertical, which was not resonant on any of the ham bands: http://www.n3ox.net/projects/lowbandvert My feedline is always operated at very low SWR and my matching networks are fairly stout and should be quite low loss. If I were to use a tuner at the shack end of the feedline on either of these antennas, there would be a lot of loss in the coax. - - - - - - Now, that said, I can't tell you the gain of these antennas in dBi. I don't have a calibrated field strength meter, I can only give anecdotal evidence for the good performance. However, if I wanted to get some good *benchmarks* for the relative performance of various antenna configurations I could do these things: 1) Measure the power in and out of each matching network This is very hard to do (impossible for me and most hams) with any useful accuracy, but it would be the definitive test of network losses. 2) Measure the field strength difference between the antenna with the matching networks I've built and the antenna just fed with RG-213 into a tuner in the shack. I can measure relative differences in field strength down to about 1dB using a step attenuator and a weak signal source that I'm listening to on my RX. This one would be possible and would be a good relative benchmark... you could compare the theoretical line and tuner losses with the measurement you made. For beams, you can get pattern benchmarks the same way. Set up a weak signal source, rotate the beam and switch attenuation in and out to keep the S-meter at the same point. You can get gain benchmarks by referencing your field strength measurements to that of a simple dipole or ground plane antenna. Field strength measurements are one of the best antenna benchmarks out there, and all you need is a calibrated FS meter or a signal generator, a reciever, and a step attenuator to make them. 73, Dan
Reply to a comment by : NORTHCOUNTRY on 2007-02-22

My ant is monoband resonant on 40m but I use a tuner anyway. The tuner does not tune it on any other band. Picture here: http://i32.photobucket.com/albums/d43/Tom838/3-500Z%20pics/40mant.jpg
W9OY2007-02-22
RE: Benchmarks
Where did you ever get the idea 3dB is trivial? Under the noise 1dB can be the difference between an new one and no contact. 3dB is trivial only when you have AGC action to burn.

73 W9OY
Reply to a comment by : N3OX on 2007-02-22

"Interesting point. So a resonant vertical dipole would then be a lot more efficient than a vertical that you would need to tune?" It entirely depends on where you put the tuner. I use a 60 foot vertical (which is, admittedly resonant on 3600kHz) on 160m, 80m, 40m, and 30m with good results. My tuner is homebrew and at the base of the antenna: http://www.n3ox.net/projects/sixtyvert I did the same thing with a 40 foot vertical, which was not resonant on any of the ham bands: http://www.n3ox.net/projects/lowbandvert My feedline is always operated at very low SWR and my matching networks are fairly stout and should be quite low loss. If I were to use a tuner at the shack end of the feedline on either of these antennas, there would be a lot of loss in the coax. - - - - - - Now, that said, I can't tell you the gain of these antennas in dBi. I don't have a calibrated field strength meter, I can only give anecdotal evidence for the good performance. However, if I wanted to get some good *benchmarks* for the relative performance of various antenna configurations I could do these things: 1) Measure the power in and out of each matching network This is very hard to do (impossible for me and most hams) with any useful accuracy, but it would be the definitive test of network losses. 2) Measure the field strength difference between the antenna with the matching networks I've built and the antenna just fed with RG-213 into a tuner in the shack. I can measure relative differences in field strength down to about 1dB using a step attenuator and a weak signal source that I'm listening to on my RX. This one would be possible and would be a good relative benchmark... you could compare the theoretical line and tuner losses with the measurement you made. For beams, you can get pattern benchmarks the same way. Set up a weak signal source, rotate the beam and switch attenuation in and out to keep the S-meter at the same point. You can get gain benchmarks by referencing your field strength measurements to that of a simple dipole or ground plane antenna. Field strength measurements are one of the best antenna benchmarks out there, and all you need is a calibrated FS meter or a signal generator, a reciever, and a step attenuator to make them. 73, Dan
Reply to a comment by : NORTHCOUNTRY on 2007-02-22

My ant is monoband resonant on 40m but I use a tuner anyway. The tuner does not tune it on any other band. Picture here: http://i32.photobucket.com/albums/d43/Tom838/3-500Z%20pics/40mant.jpg
N3OX2007-02-22
RE: Benchmarks
"I have always believed that antennas TEND to function in a reciprocal manner with respect to receiving and transmitting, but I'd like to hear more from the technical gurus out there. "

Antennas are completely reciprocal as far as the electromagnetic fields are concerned. If they weren't, the technique I use for field strength measurements would not work*.

However, because the noise floor on the HF bands can be set by noise outside the RX, and usually is, it's possible for you to transmit a signal that a station in a quieter location can hear, but when they reply at the same power level with the same path loss and the same antennas, you can't hear them.

The antennas are electromagnetically reciprocal devices, but yours is picking up additional signals that mask the desired one, so the communication path is not reciprocal.

- - - - - -

*this footnote is regarding ensuring that your RX-based FS measurements are reciprocal. your RX is probably not 50 ohm input impedance; I understand that it's often quite high. If you want to ensure that your antenna and RX *system* is reciprocal for field strength measurement purposes, you need to terminate the RX end of the cable in 50 ohms. Switching in ~20dB of attenuation as a minimum will do this.

73,
Dan
Reply to a comment by : N3OX on 2007-02-22

"Interesting point. So a resonant vertical dipole would then be a lot more efficient than a vertical that you would need to tune?" It entirely depends on where you put the tuner. I use a 60 foot vertical (which is, admittedly resonant on 3600kHz) on 160m, 80m, 40m, and 30m with good results. My tuner is homebrew and at the base of the antenna: http://www.n3ox.net/projects/sixtyvert I did the same thing with a 40 foot vertical, which was not resonant on any of the ham bands: http://www.n3ox.net/projects/lowbandvert My feedline is always operated at very low SWR and my matching networks are fairly stout and should be quite low loss. If I were to use a tuner at the shack end of the feedline on either of these antennas, there would be a lot of loss in the coax. - - - - - - Now, that said, I can't tell you the gain of these antennas in dBi. I don't have a calibrated field strength meter, I can only give anecdotal evidence for the good performance. However, if I wanted to get some good *benchmarks* for the relative performance of various antenna configurations I could do these things: 1) Measure the power in and out of each matching network This is very hard to do (impossible for me and most hams) with any useful accuracy, but it would be the definitive test of network losses. 2) Measure the field strength difference between the antenna with the matching networks I've built and the antenna just fed with RG-213 into a tuner in the shack. I can measure relative differences in field strength down to about 1dB using a step attenuator and a weak signal source that I'm listening to on my RX. This one would be possible and would be a good relative benchmark... you could compare the theoretical line and tuner losses with the measurement you made. For beams, you can get pattern benchmarks the same way. Set up a weak signal source, rotate the beam and switch attenuation in and out to keep the S-meter at the same point. You can get gain benchmarks by referencing your field strength measurements to that of a simple dipole or ground plane antenna. Field strength measurements are one of the best antenna benchmarks out there, and all you need is a calibrated FS meter or a signal generator, a reciever, and a step attenuator to make them. 73, Dan
Reply to a comment by : NORTHCOUNTRY on 2007-02-22

My ant is monoband resonant on 40m but I use a tuner anyway. The tuner does not tune it on any other band. Picture here: http://i32.photobucket.com/albums/d43/Tom838/3-500Z%20pics/40mant.jpg
AA4PB2007-02-22
RE: Benchmarks
The idea of an antenna tuner hooked to an un-balanced line (coax) is absurd
-----------------------------------------------------
Not necessarily. If you are trying to load a 75M dipole on 20M then it certainly is. If you are using the tuner to "trim up" the match a little (to keep the transmitter happy) when moving away from the resonant point of your 75M dipole then it works fine.

The added loss due to the SWR on the coax depends on the type of coax, length of the run, the frequency, and the SWR.
Reply to a comment by : AA4PB on 2007-02-22

I think Alan makes a good point. We need to understand the benchmarks and strive to make our antenna perform as close to the benchmark as possible given our particular limitations in size and dollars. For example, even the very best 75 meter mobile antennas are but a few percent efficient. On a mobile you pretty much have to live with that. It is a shame however to stick one of these in your back yard *if* you could have put up a much more efficient and less expensive wire dipole. Sometimes this sort of thing is done because the person doing it doesn't understand the performance trade-offs he is making. On the other hand, if you understand the trade-offs and have decided that this is the best senario for your particular situtaion then its a good thing.
Reply to a comment by : AA4PB on 2007-02-22

There is nothing magic about resonance. Resonance simply means that there is no inductive reactance in the load, only resistance. A non-resonant antenna element can be every bit as efficient as a resonant antenna element, sometimes more. The question is the ability to efficiently couple power from the transmitter into the antenna. We become accustomed to the resonant dipole where at resonance it has a load impedance which is a pretty good match for the 50 ohm coax cable we typically use. Its not the "resonance" that makes the difference however, it is that fact that the load matches the coax. If I were to make a "resonant" folded dipole the load impedance would be much higher than 50 ohms and it would not be a good match for the 50 ohm coax. That can result in a lot of loss in the coax, depending on the frequency, length of the coax, and type of coax. On the other hand, if I make a dipole (or doublet) of some non-resonant length greater than 1/2 wavelength and feed it with a very low loss feeder like open wire line then the loss is very low. I need a tuner to match the odd impedance at end of the feeder to the 50 ohm transmitter, but the loss in the feeder is low (even with a high SWR) and so the non-resonant antenna element works as well as the resonant example. If you can deliver the power to the antenna element it will radiate it whether it is resonant or not.
Reply to a comment by : AA4PB on 2007-02-22

The fact is (contrary to popular belief), antennas are NOT reciprocal in their transmit verses receive performance --------------------------------------------------- It depends on what you mean by "transmit verses receive performance. Antennas are indeed reciprocal BUT that means that the gain and pattern are the same on receive as they are on transmit. It doesn't necessarily address the ability to copy signals with the antenna however. The ability to copy signals is dependent on the signal to noise ratio. If adding 3dB gain to an antenna raises the signal by 3dB and also raises the noise by 3dB then the ability to copy signals hasn't changed any. That's why a poor transmit antenna can sometimes make an excellent receive antenna, because the antenna has a higher signal to noise ratio. You can be sure however that if an antenna provides 3dB of gain on transmit it will also provide 3dB of gain on receive. The problem is that it may also provide a 3dB increase in received noise.
Reply to a comment by : NORTHCOUNTRY on 2007-02-22

My ant is monoband resonant on 40m but I use a tuner anyway. The tuner does not tune it on any other band. Picture here: http://i32.photobucket.com/albums/d43/Tom838/3-500Z%20pics/40mant.jpg
KC8QFP2007-02-22
RE: Benchmarks
I also feel a discussion about TRAPS would be in order here. I like to avoid traps as I do using the matchbox.

Multi-band (traples) antennaes vs multiple antennaes is my way of dealing with the ham bands. I'd rather invest in a remote coax switch (better yet build one that can switch ladder line), instead of an expensive tuner with the roller inductor (hihi). ;)

I wonder how'd the GAP (as an example) would compare in numbers vs actual performance? I've read about them, but never used one myself. The stuff looks good on paper (advertisement), and they sound pretty good on the air when I hear people that have them, and most hams seem to like them. But I have not used them, and the proof is in the pudding. Numbers mean little because the same antenna will react differently at each location. I remember the same thing happened when I considered the Isopole and the Ringo Ranger II. I went with the Isopole, and really liked it. They both sounded good when I talked to people that used them. But the Ringo had more problems, something to consider when investing in an antenna system - maintenance and durability. I know of a ham whose GAP got pretty beat up in the wind. I have the Hustler 5BTV (had it for a long long time), and it seems indestructable (but I do not like the traps, 80m is useless on it).

My elmer taught me to pay MORE attention to my antenna, he said rigs are rigs, a hundred watt transmitter is a hundred watt transmitter regardless of the bells and whistles. He felt that the antenna is the most important piece of gear amd most hams overlook this important point. I agree with Gene (a SK now). And he said that it does not have to cost megabucks to have a great working antenna, he taught me about the many neat wire antennaes that I could make for myself, (CHEAP), a lot more fun than buying let's say, a Cushcraft. Some hams say that their randumb wires work OK for them, and maybe so. Antennaes are strange unpredictable devices. Some CBer's got a 1:1 VSWR "match" on a coat hanger! But I would not wanna be anywhere near their coat hanger when they fire up their linnikers!!!

I have been into ham radio for a long time, and I am facinated about the many things I am still learning about radidio. When you talk antennaes and numbers, remember that the PROPER GROUNDING is very significant as to the antennaes actual performance. When I gradeeated to HF, I learned that a "rubber duck" is a JOKE!!! The world above 30MHz is quite differant from the l-o-n-g antennaes that need good grounding.

On the other hand, when $$$ is no object, there are the beams, towers, and rotors to play with. I enjoyed making quads on 2m, but too big for me on HF. I guess I am a wire freak, they are much more flexable to experiment with, and the newer rigs are best left closed up and sealed tight if you know what I mean.

Most antenna discussion seems to relate to the country guys that have huge antenna farms, and the city dudes that have small backyards. The OT guys are dying off, and now it seems more people are using vertical. There are more significant differances between polarization, vertical and horizontal antennaes, then there is concerning WATTS (barefoot vs linear amps).

Whether you buy an MFJ (or whatever), or make a home brew, you will always have your disappointments in any antenna, nothing is perfect! All antennaes are problematic, they all have their individual characteristic, both great and poor in performance. If one antenna really was soooo great, everybody would buy that ONE and not the inferior ones. But we all have had our frustrations, whether we got it for free, or paid a load of $$$ for it. I like wires because they are easier to work with and are more forgiving. Simply changing the feed point can make a lot of differance. My biggest problems are height for horizontals, and grounding for verticals. Just make the best of it, I say.

In the quest for that 1:1 VSWR match, there are thousands of possibilites in antennaes, but only a handful of rigs or mics to chose from.

Enjoy folks! Don
Reply to a comment by : NORTHCOUNTRY on 2007-02-22

My ant is monoband resonant on 40m but I use a tuner anyway. The tuner does not tune it on any other band. Picture here: http://i32.photobucket.com/albums/d43/Tom838/3-500Z%20pics/40mant.jpg
N3OX2007-02-22
RE: Benchmarks
"Interesting point. So a resonant vertical dipole would then be a lot more efficient than a vertical that you would need to tune?"

It entirely depends on where you put the tuner.

I use a 60 foot vertical (which is, admittedly resonant on 3600kHz) on 160m, 80m, 40m, and 30m with good results. My tuner is homebrew and at the base of the antenna:

http://www.n3ox.net/projects/sixtyvert

I did the same thing with a 40 foot vertical, which was not resonant on any of the ham bands:

http://www.n3ox.net/projects/lowbandvert

My feedline is always operated at very low SWR and my matching networks are fairly stout and should be quite low loss. If I were to use a tuner at the shack end of the feedline on either of these antennas, there would be a lot of loss in the coax.

- - - - - -

Now, that said, I can't tell you the gain of these antennas in dBi. I don't have a calibrated field strength meter, I can only give anecdotal evidence for the good performance. However, if I wanted to get some good *benchmarks* for the relative performance of various antenna configurations I could do these things:

1) Measure the power in and out of each matching network

This is very hard to do (impossible for me and most hams) with any useful accuracy, but it would be the definitive test of network losses.

2) Measure the field strength difference between the antenna with the matching networks I've built and the antenna just fed with RG-213 into a tuner in the shack.

I can measure relative differences in field strength down to about 1dB using a step attenuator and a weak signal source that I'm listening to on my RX. This one would be possible and would be a good relative benchmark... you could compare the theoretical line and tuner losses with the measurement you made.

For beams, you can get pattern benchmarks the same way. Set up a weak signal source, rotate the beam and switch attenuation in and out to keep the S-meter at the same point. You can get gain benchmarks by referencing your field strength measurements to that of a simple dipole or ground plane antenna.

Field strength measurements are one of the best antenna benchmarks out there, and all you need is a calibrated FS meter or a signal generator, a reciever, and a step attenuator to make them.

73,
Dan
Reply to a comment by : NORTHCOUNTRY on 2007-02-22

My ant is monoband resonant on 40m but I use a tuner anyway. The tuner does not tune it on any other band. Picture here: http://i32.photobucket.com/albums/d43/Tom838/3-500Z%20pics/40mant.jpg
AA4PB2007-02-22
RE: Benchmarks
I think Alan makes a good point. We need to understand the benchmarks and strive to make our antenna perform as close to the benchmark as possible given our particular limitations in size and dollars.

For example, even the very best 75 meter mobile antennas are but a few percent efficient. On a mobile you pretty much have to live with that. It is a shame however to stick one of these in your back yard *if* you could have put up a much more efficient and less expensive wire dipole. Sometimes this sort of thing is done because the person doing it doesn't understand the performance trade-offs he is making. On the other hand, if you understand the trade-offs and have decided that this is the best senario for your particular situtaion then its a good thing.
Reply to a comment by : AA4PB on 2007-02-22

There is nothing magic about resonance. Resonance simply means that there is no inductive reactance in the load, only resistance. A non-resonant antenna element can be every bit as efficient as a resonant antenna element, sometimes more. The question is the ability to efficiently couple power from the transmitter into the antenna. We become accustomed to the resonant dipole where at resonance it has a load impedance which is a pretty good match for the 50 ohm coax cable we typically use. Its not the "resonance" that makes the difference however, it is that fact that the load matches the coax. If I were to make a "resonant" folded dipole the load impedance would be much higher than 50 ohms and it would not be a good match for the 50 ohm coax. That can result in a lot of loss in the coax, depending on the frequency, length of the coax, and type of coax. On the other hand, if I make a dipole (or doublet) of some non-resonant length greater than 1/2 wavelength and feed it with a very low loss feeder like open wire line then the loss is very low. I need a tuner to match the odd impedance at end of the feeder to the 50 ohm transmitter, but the loss in the feeder is low (even with a high SWR) and so the non-resonant antenna element works as well as the resonant example. If you can deliver the power to the antenna element it will radiate it whether it is resonant or not.
Reply to a comment by : AA4PB on 2007-02-22

The fact is (contrary to popular belief), antennas are NOT reciprocal in their transmit verses receive performance --------------------------------------------------- It depends on what you mean by "transmit verses receive performance. Antennas are indeed reciprocal BUT that means that the gain and pattern are the same on receive as they are on transmit. It doesn't necessarily address the ability to copy signals with the antenna however. The ability to copy signals is dependent on the signal to noise ratio. If adding 3dB gain to an antenna raises the signal by 3dB and also raises the noise by 3dB then the ability to copy signals hasn't changed any. That's why a poor transmit antenna can sometimes make an excellent receive antenna, because the antenna has a higher signal to noise ratio. You can be sure however that if an antenna provides 3dB of gain on transmit it will also provide 3dB of gain on receive. The problem is that it may also provide a 3dB increase in received noise.
Reply to a comment by : NORTHCOUNTRY on 2007-02-22

My ant is monoband resonant on 40m but I use a tuner anyway. The tuner does not tune it on any other band. Picture here: http://i32.photobucket.com/albums/d43/Tom838/3-500Z%20pics/40mant.jpg
W4LGH2007-02-22
RE: Benchmarks
This is a very interesting article, and touches on many points. The first is antenna GAIN. Altho I understand the principle very well, including how this gain is achieved, by beaming the radiated power more directional, I have always found the idea of saying an antenna has gain to be an oxymoron. When in fact an antenna (passive) can NOT produce any gain, it can however have less loss, but nothing is FREE, and once again compromises are made to get this gain.
Another subject touched, DBI and DBD. Since you can NOT build an isotropic antenna on earth, and to my knowledge they haven't built one in free space yet, I find DBI to be an invalid rating and useless. DBD however is a more valid rating and since we CAN build dipoles on earth to compair to, the rating is more realistic. However you'll hardly ever is a DBD rating on an antenna.

The idea of an antenna tuner hooked to an un-balanced line (coax) is absurd. The only thing you are tuning is the impedance at the shack end of the coax. The mis-match at the antenna still exsists and is still very REAL!! It may allow you to do something you couldn't without it, but you are only fooling yourself! Not to mention the other factor touched on, loss in the tuner..the best tuner made will have between an 11% to 15% loss!! Some of the cheaper tuners go way higher, as much as 40%!! Now you take your ant that has a 3:1 swr ratio, which is about a 25% loss, 3db loss in your coax, and a 15% loss in your tuner. Your meter on the tuner now shows 1:1 swr, output from your radio is showing a full 100watts, and you are HAPPY, but actually here is what you have...approx.
100-15(tuner loss)=85-42.5(3dbcoax)=42.5-10.5(3:1swr)= 32 watts!!! 1/3 of your power is being radiated!!! Not very good, but your meter says 100watts and you are happy. You will NOT find a tuner in use in my shack! I own a little MFJ941E piece of junk, but was using it to match a long wire to a receiver.
Those figures above also work on your receiver too! Altho quite different, there is a big loss in your receive signal as well.

Hope all this gives you something to think about. Al of my antennas are resonate, and are fed with LMR-400 cable (basically no loss @ HF) I have measured my power leaving the shack @ 100watts, and at the antenna there will be 98watts! This was done not so much for transmit, but for the receive side. If you can't hear them, you CAN NOT talk to them!!!!

I do NOT claim my figures to be 100% accurate, but close enough to show an example of whats happening.

73 de W4LGH - Alan
http://www.w4lgh.com

Reply to a comment by : NORTHCOUNTRY on 2007-02-22

My ant is monoband resonant on 40m but I use a tuner anyway. The tuner does not tune it on any other band. Picture here: http://i32.photobucket.com/albums/d43/Tom838/3-500Z%20pics/40mant.jpg
AA4PB2007-02-22
RE: Benchmarks
There is nothing magic about resonance. Resonance simply means that there is no inductive reactance in the load, only resistance.

A non-resonant antenna element can be every bit as efficient as a resonant antenna element, sometimes more. The question is the ability to efficiently couple power from the transmitter into the antenna.

We become accustomed to the resonant dipole where at resonance it has a load impedance which is a pretty good match for the 50 ohm coax cable we typically use. Its not the "resonance" that makes the difference however, it is that fact that the load matches the coax. If I were to make a "resonant" folded dipole the load impedance would be much higher than 50 ohms and it would not be a good match for the 50 ohm coax. That can result in a lot of loss in the coax, depending on the frequency, length of the coax, and type of coax.

On the other hand, if I make a dipole (or doublet) of some non-resonant length greater than 1/2 wavelength and feed it with a very low loss feeder like open wire line then the loss is very low. I need a tuner to match the odd impedance at end of the feeder to the 50 ohm transmitter, but the loss in the feeder is low (even with a high SWR) and so the non-resonant antenna element works as well as the resonant example.

If you can deliver the power to the antenna element it will radiate it whether it is resonant or not.
Reply to a comment by : AA4PB on 2007-02-22

The fact is (contrary to popular belief), antennas are NOT reciprocal in their transmit verses receive performance --------------------------------------------------- It depends on what you mean by "transmit verses receive performance. Antennas are indeed reciprocal BUT that means that the gain and pattern are the same on receive as they are on transmit. It doesn't necessarily address the ability to copy signals with the antenna however. The ability to copy signals is dependent on the signal to noise ratio. If adding 3dB gain to an antenna raises the signal by 3dB and also raises the noise by 3dB then the ability to copy signals hasn't changed any. That's why a poor transmit antenna can sometimes make an excellent receive antenna, because the antenna has a higher signal to noise ratio. You can be sure however that if an antenna provides 3dB of gain on transmit it will also provide 3dB of gain on receive. The problem is that it may also provide a 3dB increase in received noise.
Reply to a comment by : NORTHCOUNTRY on 2007-02-22

My ant is monoband resonant on 40m but I use a tuner anyway. The tuner does not tune it on any other band. Picture here: http://i32.photobucket.com/albums/d43/Tom838/3-500Z%20pics/40mant.jpg
K8AG2007-02-22
RE: Benchmarks
The problem with this article, Alan, is that it assumes that we all have infinite time, resources and land to put up as many wires as we see fit. I have a ZS6BKW which is NOT a perfect antenna, but a compromise. Like many of us, I feel that my antenna is the optimal antenna for my situation, and for the amount of time I choose to put into ham radio. All antennas, even resonant dipoles, are a compromise of some sort.

I feel that these kinds of articles can scare folks away from trying something that might be "less than optimal". They keep people off the air (especially HF) because they don't have the facilities or inclination to put up the "perfect, textbook antenna". That somehow those of us who have compromise systems should not bother to even go on the air.

Yes it may be a great thing to understand the optimal so we can perhaps improve what we have. But remember that some of us live on small suburban lots, or in antenna restricted environments. And some of us just don't have the time to spend tending five or six antennas.

My 2 cents.

73, JP, K8AG
Reply to a comment by : AA4PB on 2007-02-22

The fact is (contrary to popular belief), antennas are NOT reciprocal in their transmit verses receive performance --------------------------------------------------- It depends on what you mean by "transmit verses receive performance. Antennas are indeed reciprocal BUT that means that the gain and pattern are the same on receive as they are on transmit. It doesn't necessarily address the ability to copy signals with the antenna however. The ability to copy signals is dependent on the signal to noise ratio. If adding 3dB gain to an antenna raises the signal by 3dB and also raises the noise by 3dB then the ability to copy signals hasn't changed any. That's why a poor transmit antenna can sometimes make an excellent receive antenna, because the antenna has a higher signal to noise ratio. You can be sure however that if an antenna provides 3dB of gain on transmit it will also provide 3dB of gain on receive. The problem is that it may also provide a 3dB increase in received noise.
Reply to a comment by : NORTHCOUNTRY on 2007-02-22

My ant is monoband resonant on 40m but I use a tuner anyway. The tuner does not tune it on any other band. Picture here: http://i32.photobucket.com/albums/d43/Tom838/3-500Z%20pics/40mant.jpg
W9PMZ2007-02-22
RE: Benchmarks
The radiation pattern is the issue. The radiation pattern is the same for transmit and receive. This means that the antennas obeys reciprocity.

However, there may be valid reasons to use different antennas under different circumstances to improve favored performance.

But it was incorrect to say that antennas do not obey reciprocity.

73,

Carl - W9PMZ
Reply to a comment by : NI0C on 2007-02-22

W9PMZ wrote: "the antenna still obeys reciprocity" True enough, Carl-- but on the lowbands in particular, signal-to-noise ratio is crucial for receiving, and good transmitting antennas often mask the received signals with a lot of noise. That's why many lowband operators will use a big vertical with a lot of radials for transmitting, but perhaps a small loop or low wire or dipole for receiving purposes. I'm sure that's what Alan was getting at in his article. 73, Chuck NI0C
Reply to a comment by : NORTHCOUNTRY on 2007-02-22

My ant is monoband resonant on 40m but I use a tuner anyway. The tuner does not tune it on any other band. Picture here: http://i32.photobucket.com/albums/d43/Tom838/3-500Z%20pics/40mant.jpg
NI0C2007-02-22
RE: Benchmarks
W9PMZ wrote:
"the antenna still obeys reciprocity"

True enough, Carl-- but on the lowbands in particular, signal-to-noise ratio is crucial for receiving, and good transmitting antennas often mask the received signals with a lot of noise. That's why many lowband operators will use a big vertical with a lot of radials for transmitting, but perhaps a small loop or low wire or dipole for receiving purposes.

I'm sure that's what Alan was getting at in his article.

73,
Chuck NI0C
Reply to a comment by : NORTHCOUNTRY on 2007-02-22

My ant is monoband resonant on 40m but I use a tuner anyway. The tuner does not tune it on any other band. Picture here: http://i32.photobucket.com/albums/d43/Tom838/3-500Z%20pics/40mant.jpg
AA4PB2007-02-22
RE: Benchmarks
The fact is (contrary to popular belief), antennas are NOT reciprocal in their transmit verses receive performance
---------------------------------------------------
It depends on what you mean by "transmit verses receive performance.

Antennas are indeed reciprocal BUT that means that the gain and pattern are the same on receive as they are on transmit. It doesn't necessarily address the ability to copy signals with the antenna however. The ability to copy signals is dependent on the signal to noise ratio. If adding 3dB gain to an antenna raises the signal by 3dB and also raises the noise by 3dB then the ability to copy signals hasn't changed any. That's why a poor transmit antenna can sometimes make an excellent receive antenna, because the antenna has a higher signal to noise ratio.

You can be sure however that if an antenna provides 3dB of gain on transmit it will also provide 3dB of gain on receive. The problem is that it may also provide a 3dB increase in received noise.
Reply to a comment by : NORTHCOUNTRY on 2007-02-22

My ant is monoband resonant on 40m but I use a tuner anyway. The tuner does not tune it on any other band. Picture here: http://i32.photobucket.com/albums/d43/Tom838/3-500Z%20pics/40mant.jpg
KT8K2007-02-22
RE: Benchmarks
It is amazing how many ops push their 100w or more into a lossy and/or far-from-resonant system, make contacts, and never realize their radiated signal is actually in the QRP range. As a dedicated QRP op I have found that I can do great with efficient and typically resonant antennas -- even better than many (most?) of my friends who are running 100w or more.

I always avoid having a tuner in line if I can do without it, and I usually can. As for SWR, I have made many contacts with my 5 watts using antennas which, at the frequency in use, had an SWR above 3:1. Granted, efficiency was relatively poor, but I wasn't going to take down my 80m dipole (for example) and prune it for the high end of the band just for phone contacts, when it was designed and cut for the CW end of the band where I spend most of my time. I still made contacts and had fun, and accepted that my signal was going to be a half S-unit or more weaker. That didn't prevent me from being heard, often very well (thank you, propagation gods).

Good article, Alan, though I would have liked a little more technical meat to it. I have always believed that antennas TEND to function in a reciprocal manner with respect to receiving and transmitting, but I'd like to hear more from the technical gurus out there.
Best rx to all - Tim, KT8K
Reply to a comment by : NORTHCOUNTRY on 2007-02-22

My ant is monoband resonant on 40m but I use a tuner anyway. The tuner does not tune it on any other band. Picture here: http://i32.photobucket.com/albums/d43/Tom838/3-500Z%20pics/40mant.jpg
NORTHCOUNTRY2007-02-22
Benchmarks
My ant is monoband resonant on 40m but I use a tuner anyway. The tuner does not tune it on any other band.

Picture here:

http://i32.photobucket.com/albums/d43/Tom838/3-500Z%20pics/40mant.jpg
N1EY2007-02-22
RE: Benchmarks
How is a vertical dipole more efficient? It would only depend on the ground system and the counterpoise. A regular vertical with a good ground and counterpoise is going to have positive dbI. A vertical dipole might not.

N1EY
Reply to a comment by : ONAIR on 2007-02-22

Interesting point. So a resonant vertical dipole would then be a lot more efficient than a vertical that you would need to tune?
W9PMZ2007-02-22
RE: Benchmarks
"antennas are NOT reciprocal in their transmit verses receive performance"

Rewriting text books?

Most antenna books that I have been privy to read starts the treatment of antennas by making a statement:

"In this section we show that the radiation pattern of an antenna is the same whether it is used as a transmitting antenna or a receiving antenna. Reciprocity allows the calculation or measurement of an antenna pattern in either the transmit or receive case." (from Antenna Theory and Design by Stutzman and Thiele, page 40)

Propagation at HF makes the antennas properties (height, length, etc) the issue, but the antenna still obeys reciprocity.

73,

Carl - W9PMZ
Reply to a comment by : ONAIR on 2007-02-22

Interesting point. So a resonant vertical dipole would then be a lot more efficient than a vertical that you would need to tune?
ONAIR2007-02-22
Benchmarks
Interesting point. So a resonant vertical dipole would then be a lot more efficient than a vertical that you would need to tune?