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[Articles Home]  [Add Article]  

Two HF Antennas One Feedline

Ken Villone (KU2US) on September 10, 2007
View comments about this article!

Attention all antenna gurus: We as ham radio operators are encouraged to experiment. This definitely is an experiment, but I cannot figure out why this experiment performs the way it does… This is what I did -- A G5RV up 50 feet configured as a inverted "V", and a 5BTV vertical ground mounted on one 50 ohm coax feedline (RG-8 mini). The two feedlines are connected to a coax "T" connector. The coax feedline from each antenna is approx. the same length to the "T". -- One coax line to my shack from the "T" which is outside my house. A tuner is used, of course.

The receive is phenomenal, and less noisy. Am I receiving from the best antenna or both? Transmitting is another story. -- Very acceptable SWR (1.5:1 or lower) after tuning. On air reports are great! The vertical is better for DX because of its lower angle of radiation, and the G5RV is better for short distances, but is my transmitting power split between both antennas?

My radio is seeing one antenna, but both antennas are quite resonant. After hours of testing on air I have come to this conclusion, both antennas together perform better than each one separately. The transmit signal strength is stronger, I get better return signal reports, and the reception is at least 2-4 Db higher with the same or less noise.

My conditions are 100 watts out or 5 watts QRP, nothing fancy and no amplifier. The vertical has 3 resonant ground radials for each band-buried in the soil.

Have I stumbled on to something, or just lucky? OK gurus, have fun with this one, I am... I am really trying to find out what is happening here-for real.

Thanks, Ken

Member Comments:
This article has expired. No more comments may be added.
 
Two HF Antennas One Feedline  
by G3LBS on September 10, 2007 Mail this to a friend!
Ken there is room for much more experimentation on combined antennas. I had a G5RV and its main lobe wasn't quite where I wanted it, so I put up another one about 30 degrees from the first.
Then I thought could I join them together, so I simulated the combination. Each antenna was fed with 300 ohm twin, no coax, all the way to a Johnson Matchbox.
I goined the twin feeders in parallel at the Matchbox and behold that filled in the nulls without switching!
Gil W2/G3LBS
 
Two HF Antennas One Feedline  
by K1CJS on September 10, 2007 Mail this to a friend!
You may well get better results, but remember that your transmit power IS split between the two antennas--only half of your power is reaching either one. I haven't done the same as you have so I can't say for certain, but chances are you've just been lucky.

Your radio is seeing BOTH antennas, not just one, and your reception is the addition of the signals from both, which is probably why your reception is 'phenominal'. As to the absence of noise, again, the chances are you've been lucky again.

If it works for you, use it! Good luck and 73.
 
Two HF Antennas One Feedline  
by N0AH on September 10, 2007 Mail this to a friend!
Gear up for the sand blasters..............
 
Two HF Antennas One Feedline  
by K5VY on September 10, 2007 Mail this to a friend!
Ken, as the old saying goes, "I'd rather be lucky than good any time!" Regardless of how you got there, you've obviously got a nice match between the two antennas and your feedline. As my old mentor Bill Orr, W6SAI (SK), would say: "...When all else fails, get as much wire out there as you can..".There may even be a mathematical formula around somewhere to explain all that. Who cares? Your success is really all that counts. Yes, you're splitting your transmitter power between the two antennas, and your Rx is looking at them both equally. You are enjoying enhanced Rx and Tx. Look this up on EZNEC if you must, but I doubt you'll find much of an answer. Instead, GOTA!! and enjoy your ham radio experience.
Best 73,
Garland, K5VY
 
Two HF Antennas One Feedline  
by K9IUQ on September 10, 2007 Mail this to a friend!
Get a bunch of those Coax T's and paint them black.
Advertise on e-bay as "Antenna Doublers".

Guaranteed to lower your RX noise and Increase your TX power by xx db. Also sell them 2 to a pack. These would be called Magic Miracle Antenna Quadropulers which would work twice as good as a single T.

Making them in designer colors would even be better than black. You could charge a premium for this. You could get very rich as there are a lot of clueless newbies out there......

LMAO
Stan K9IUQ
 
RE: Two HF Antennas One Feedline  
by AA4PB on September 10, 2007 Mail this to a friend!
The receive signal is combined from the two antennas and the transmit signal is split between them. It may not be a 50/50 split however, depending on the impedance of each antenna and any difference in length of coax between each antenna and the "T". How the two signals combine in any given direction also depends on the separation between the two antennas. There are many variables to consider.

The fact that you can adjust the tuner to provide a 1.5:1 SWR at the transmitter doesn't say anything about the SWR and any resulting loss on the coax between the tuner and the antennas.

The bottom line is if it works, use it. I wouldn't draw the conclusion from it that everyone will have the same results if they combine two antennas in the same manner. Everyone will have a different set of variables to work with.
 
RE: Two HF Antennas One Feedline  
by WW5AA on September 10, 2007 Mail this to a friend!
The problem will be phasing, not that it will be a problem all the time. At the point where nulls and voids overlap, the results will be very unpredictable. As said however, it is all based on expectations. Have fun!

73, de Lindy
 
RE: Two HF Antennas One Feedline  
by KI6EAA on September 10, 2007 Mail this to a friend!
"as there are a lot of clueless newbies out there......"

...and, when it comes to social skills, a lot of clueless Old Timers out here (on eHam).
 
RE: Two HF Antennas One Feedline  
by W4LGH on September 10, 2007 Mail this to a friend!
KI6EAA...
"as there are a lot of clueless newbies out there......" ...and, when it comes to social skills, a lot of clueless Old Timers out here (on eHam).

You have to excuse Stan, as he has no social skills. Not his fault tho, as he was never taught them.

Not exactly sure what is taking place here as 2 50ohm line would come down to 25ohms. I would have to say you got lucky, as antenna 101 would say you couldn't do that. I agree with the phazing issues, and thechnically they should be out of phaze with each other canceling each other out. You also have a low feeding a high...25ohms on the antenna side and 50ohms on the radio side during receive, this along should know the signals down by 3db. But I has seen wierder things work.

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


 
RE: Two HF Antennas One Feedline  
by KE3HO on September 10, 2007 Mail this to a friend!
Maybe the next step would be to home brew a relay box that will allow you to remotely switch between the antennas individually as well as to run them both in parallel as they now are.

73 - Jim
 
RE: Two HF Antennas One Feedline  
by KE6VG on September 10, 2007 Mail this to a friend!
Can any one say Array Solutions Stack Match.

People have been doing this for years. Usually they use two or three antennas that they can model. Two or three verticals or two or more beams on a tower. But, there should be no problem using a dipole and a vertical. You just might have a hard time modeling it.

I say, good job. Now, set up some different phasing lines and play with it even more.
 
RE: Two HF Antennas One Feedline  
by K9IUQ on September 10, 2007 Mail this to a friend!
KI6EAA (clueless Newbie) says
"as there are a lot of clueless newbies out there......"

...and, when it comes to social skills, a lot of clueless Old Timers out here (on eHam).

........................................................
K9IUQ (clueless Old Timer)

How many of my "Miracle Antenna Doublers" or "Super New and Improved Quadropulers" would you like? Painted in your choice of designer colors.

Guaranteed to be 25 db over a Wet Noodle. Excellent F/B. Works with any antenna. Low SWR. 160 thru 6 meters.NO ROTATOR needed. Perfect for those antenna theory challenged newbies.

I also have a "Transceiver Doubler". Yes, combine TWO RADIOS with my (colors available to match your radio) "Transceiver Doubler". 2 - 100watt radios will get you 200 watts to your antenna. Double the DX range.

Combine my "Transceiver Doubler" with my fantastic "Antenna Quadropuler" and get 200 watts power to 4 antennas. Guaranteed to get you noticed on the band.

Stan K9IUQ








 
RE: Two HF Antennas One Feedline  
by WB2WIK on September 10, 2007 Mail this to a friend!
Problem is, you didn't say what frequency you are (or were) using for this.

A G5RV (102' version) can "cover" eight bands; the 5BTV can cover five bands.

That you would be lucky enough to have this combination "work" well on five bands is very unlikely. If that happened, I'd recommend you buy some lottery tickets because you're extremely lucky.

However, the "happy accident" phased antenna system can work just fine when combining dissimilar antennas -- usually it works for just one band, though.

WB2WIK/6
 
RE: Two HF Antennas One Feedline  
by N6NKN on September 10, 2007 Mail this to a friend!
Boy,

It sure didn't take long for this thread to go to hell in a handbasket.

Cheers,

Rick N6NKN
 
RE: Two HF Antennas One Feedline  
by WR8D on September 10, 2007 Mail this to a friend!
I have a buddy here locally feeding two loops like this. He lives in a valley and has a 80 meter loop infront of his home and a 160 meter loop in the back of it. He's feeding them both via the same monster balun with 450ohm wire and talks all the time of incredible reports. Weird combinations of antennas really play like this. He just hooked both antennas to the same balun and then runs one coax into his shack to a big tuner and it plays very well.

73 John WR8D
 
RE: Two HF Antennas One Feedline  
by KB9CRY on September 10, 2007 Mail this to a friend!
After hours of experimentation....


Describe exactly what you were doing during these hours. If you didn't do A/B testing then you really can't comment on how well the combo is performing since you have to include band and propagation variables into the mix.

But, if you think the combo is better, then it is.
 
RE: Two HF Antennas One Feedline  
by W6TH on September 10, 2007 Mail this to a friend!
.

I do it the easy way by using two antennas and two receivers.

I have two Icom IC 718 transceivers, one is connected to a Center fed Zepp at 50 feet, the other is fed with a Hustler five band trap vertical up at 14 feet, fed with eight radials cut at thirty four feet. The output of each receiver is combined to one single speaker or both speakers for other uses. I call this system my diversity controlled system and use both for receiving and transmitting, if necessary, on the 40, 20, 15 and the 10 meter bands.

I can then distinguish between the two incoming signals without any switching or can do the same with separate speakers. I also, can switch both off of the diversity and then have my Icom IC 756 Pro III take over to make contact with the station wanted to work, also can determine which antenna will work best for my contact.

The diversity system runs 24/7 and can scan several bands if wanted.

Which antenna do I prefer as the best? That is my secret and not to reveal.

73, W6TH.

.:
 
RE: Two HF Antennas One Feedline  
by N3JBH on September 10, 2007 Mail this to a friend!
Aw come on Vito tell us
 
RE: Two HF Antennas One Feedline  
by KE3WD on September 10, 2007 Mail this to a friend!
Depending upon how far apart horizontally speaking that these two antennas are located, the G5, being in inverted vee formation, is likely working along with the vertical as one large diameter vertical for all intents and purposes.

Old lower power AM radio tower designs sometimes used to do things like that, hot tower coupled to insulated guys, etc.

Presumably this fellow is using an antenna matchbox, since he has a G5, any lowered impedence situation ought to be easily handled by a good wide range matchbox.

And don't even worry about the power split. Anyone at the receiving end, it appears as just one larger antenna.

A Field Strength study will likely quickly confirm this once you get out of the nearfield.


KE3WD
 
RE: Two HF Antennas One Feedline  
by W9OY on September 10, 2007 Mail this to a friend!
Vito

When you transmit do you just yell into the speaker?
 
RE: Two HF Antennas One Feedline  
by W4VR on September 10, 2007 Mail this to a friend!
Ken: Feeding two antennas in this manner may result in different performance characteristics depending on the band. It appears you have hit the right combination for one band. Many years ago when HF was used more extensively for commercial transcontinental communciations, using two or more antennas for receiving (diversity reception) was quite common to help reduce fading. If somehow you could install a remote switch to transfer your receiver from one antenna to the other and also listen with the two in parallel, I'm willing to bet that your reception on one of the antennas would not be much different than with the two in parallel depending on propagation conditions...try it.
 
RE: Two HF Antennas One Feedline  
by K6AER on September 10, 2007 Mail this to a friend!

Ken,

As others have said, on the particular band you have done testing, you may just be lucky. Generally combining two resonate antennas of the same impedance (50 Ohms) will yield an impedance that is half or about 25 ohms. Your VSWR will be about 2:1 at the junction.

Several physical proprieties could be taking place at once.

• The reason you noise floor is lower is due to the mismatch (loss) and that the antenna pattern may no longer be pointed in the direction of the noise source.

• The two antennas may be canceling out their antenna patterns and have less gain in which to pick up atmospheric noise.

• Your ability to work stations is antidotal. During good band conditions (and yes we have good days at the bottom of the sun spot cycle) a poor antenna can work very well.

• It takes two to tango, having said that don’t forget the guy at the other end may have a very good station in a quiet location running 1.5 KW with a good beam to make up the difference. He is doing the heavy lifting. Typical beam up high will add 20 dB to the receive and transmit signal over a dipole.

Many antennas favor different angles of radiation and on some days when the band is poor only local stations are available and a high arrival angle is best. When the band goes long the vertical may out perform the dipole (A G5RV is a dipole).

The only way to asses your antenna combination is to switch between the two antennas and then compare the signal with the two antennas combined. This has to be done many times, literally hundreds of tests over many weeks, for the bands are rife with fading and one minute the results will be for one antenna and the next minuet the results will favor another antenna or both.

I have found these antenna tenets to be true;

• Get your antenna as high as possible.
• Put all your money into the antenna and if any is left over buy a radio.
• An ugly antenna up high will out perform a beautiful antenna down low.
• Tall towers are a joy to behold.
• A $100 radio with a $10,000 antenna will blow away a $10,000 radio with a $100 antenna every time.
• Always remember the last 5 dB is very expensive.
• A quiet antenna location is priceless.

Having fun with antennas is the best part of ham radio for it takes very little money to get decent results.
 
RE: Two HF Antennas One Feedline  
by W6TH on September 10, 2007 Mail this to a friend!
.
N3JBH on September 10
Aw come on Vito tell us


No way, I ain't gonna make u smarter than I.

.:

 
RE: Two HF Antennas One Feedline  
by W6TH on September 10, 2007 Mail this to a friend!
.
W9OY on September 10
Vito

When you transmit do you just yell into the speaker?


There you go again, with your trick question.

I am not one of those who can easily tell the difference between year and year, like a meteorologist with reliable charts to go by. I am not even one who can refer to a kind of event or quirk of fashion as typically '70s or '80s. All I am capable of is sensing the prevalent groundswells of life and registering, on occasion, the undertow, which is often contradictory.

.:
 
RE: Two HF Antennas One Feedline  
by N3JBH on September 10, 2007 Mail this to a friend!
You just have to love Vito's wisdom.
Some day Vito some day i will learn, :)
 
RE: Two HF Antennas One Feedline  
by K9IUQ on September 10, 2007 Mail this to a friend!
K6AER says

these antenna tenets to be true;

• Get your antenna as high as possible.
• Put all your money into the antenna and if any is left over buy a radio.
• An ugly antenna up high will out perform a beautiful antenna down low.
• Tall towers are a joy to behold.
• A $100 radio with a $10,000 antenna will blow away a $10,000 radio with a $100 antenna every time.
• Always remember the last 5 dB is very expensive.
• A quiet antenna location is priceless.
.........................................................

All very True. But you missed an important antenna tenet.

Never install an antenna in nice sunny warm weather. ALWAYS pick a nasty cold raw (wind is your friend)rainy or snowy day.

The performance of your antenna will be directly proportional to the installation WX condx.

Nasty WX = Superb Antenna Performance
Beautiful WX = Wet Noodle Performance Antenna

Stan K9IUQ






 
RE: Two HF Antennas One Feedline  
by W6TH on September 10, 2007 Mail this to a friend!
.
N3JBH
You just have to love Vito's wisdom.
Some day Vito some day i will learn, :)
.....................................................

The fact that you are in a peculiarity of behavior situation, I will ignore you and your actions and get back to KU2US, who makes sense as that is what most hams do when on their first experiment.


.:
 
RE: Two HF Antennas One Feedline  
by N6AJR on September 10, 2007 Mail this to a friend!
it is kind of like a fan dipole, lets say your radio shoots 100 watts upo the pipe at frequency x. at freq X the vert is more resonant than the g5 and has a lower impedance to the radio than the other so more power flows to the vert and less to the g5rv.

now tune to freq y, and the g5 is a better match so more power flows to the g5 and less to the vert.

so at some point each antenna has a specific resonance and impeadance to the flow of power so each will transmit mnore or less that the other depending on frequency, tuning of the specific antenna, surrounding stuff ( like stucco chicken wire etc) and it wil c=vary a lot.

most antennas are recirprocal on recieve, so the will work similar as recieve antennas too. especially dependent on the signal being ether vertical, horizontal or some where in between polerazation.

good luck and have fun
 
RE: Two HF Antennas One Feedline  
by W7AIT on September 10, 2007 Mail this to a friend!
You seemed to ignore:
1. SWR
2. Impedance matching
3. Power being split in half
4. Antenna radiation resistance
5. Antenna Efficiency
6. Antenna patterns – all screwed up
7. Variables over HF over the air reports – uncontrolled conditions and results
8. Did you try modeling the antennas?

May I suggest some reading and study materials for you.

1. Any ARRL Handbook
2. The ARRL Antenna Handbook.
3. The ARRL General or Extra study books

You may find many of the answers to your questions in there. And it may prompt more questions for us after you’ve read them.

Generally speaking, you can’t connect two antennas in parallel and get any meaningful results.

Maybe you should try the “Slinky Antenna” – I hear those work fine…..


 
RE: Two HF Antennas One Feedline  
by W6TH on September 10, 2007 Mail this to a friend!
.
To make two different antennas work on one coax line, one must have both antennas at the same impedance. To load both together, one must also run a quarter wavelength line to both and feed them in phase with each other. This will be both tied together in phase, but will only be resonant on one single wavelength, not a multiband set up using coax.

This system has been used, tried and tested for many years, by many, new and old hams and still exists today.

.:
 
RE: Two HF Antennas One Feedline  
by N7YA on September 10, 2007 Mail this to a friend!
>>....important antenna tenet<<


Say that 10 times fast.
 
Two HF Antennas One Feedline  
by K1DA on September 10, 2007 Mail this to a friend!
I am intertested in how a buried radial can be made resonant--- are they buried in styrofoam or did you compensate for the effect of being surrounded by soil instead of in free air? What formula did you use?
Howq did you test them?
 
RE: Two HF Antennas One Feedline  
by AA4PB on September 10, 2007 Mail this to a friend!
Actually, the phasing harnes (i.e. the coax between the T connector and the antennas) is usually made from a 1/4 wavelength (or an odd multiple) of 75 ohm coax. The mismatch between the 50 ohm antenna and the 75 ohm coax cause the impedance 1/4 wavelength back down the line to become 100 ohms. When you parallel the two 100 ohm impedances at the T connector the result is 50 ohms. You wind up with a nice 50 ohm load and the power being equally split between the two antennas and in phase.
 
RE: Two HF Antennas One Feedline  
by W6TH on September 10, 2007 Mail this to a friend!
.
..................Two HF Antennas One Feedline..........

Yes, no problem. I have taken a 4 element 20 meter Yagi Uda array at 50 feet on my tower, below the 4 element Yagi I had installed a 4 element Yagi Uda array at 34 feet for 15 meters and fed them in phase using a single coax feed. No antenna tuners used.

.:
 
RE: Two HF Antennas One Feedline  
by G3LBS on September 10, 2007 Mail this to a friend!
Surely the experiments in combining antennas are the way forward to encourage spin-off towards electronic switching, which is the future, rather than heavy engineering, which for most is less appropriate in a hobby conducted in a domestic bliss or environment?
Except for those Tarzans who must put on a show for the neighbors and passers-by?
I had no problem simulating my two G5RVs before I erected them. Readers should not assume coax is being used in all these experiments and therefore the parallel impedance may not be 25 ohms, or if it is may still be tunable, for example by adding a series variable cap to cold side of a Matchbox input link.
 
RE: Two HF Antennas One Feedline  
by NB3O on September 10, 2007 Mail this to a friend!
...........Two HF Antennas One Feedline.........
I got an 80 meter dipole connected to the same feedline as my 40 meter dipole..........the wires are separated like the blades of a fan.....
 
RE: Two HF Antennas One Feedline  
by W4LGH on September 10, 2007 Mail this to a friend!
NB3O said...."Two HF Antennas One Feedline.........
I got an 80 meter dipole connected to the same feedline as my 40 meter dipole..........the wires are separated like the blades of a fan"

This is completely different from whats being talked about here. "blades of a fan" Hmmm..guess thats how it got its name... Fan Dipole.

I am gonna give up on this topic! Antennas seem to such a mystery to so many hams, its amazing that they can get on the air. Just goes to prove a little RF will go a long way! And don't forget your antenna tuner in your shack hooked to coax, that will let you tune any antenna to any frequency! Try it next time just using the coax, no antenna, bet it will load it up, perfect SWR, but who you gonna talk to? And if you can't detect a tad of sarcasm in my writing...oh well.

By the way, a FAN DIPOLE is a good working multiband HF antenna, can be fed with coax, and requires no tuner! I think some of these guys need to go back to "Antenna 101"

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

Remember... a little RF will go a long way...but a lot of RF will go the same distance with a lot better Signal to noise ratio!
 
RE: Two HF Antennas One Feedline  
by KE3WD on September 10, 2007 Mail this to a friend!
>>Your ability to work stations is antidotal<<

Guess this means that the antenna must be poisonous or something...


 
Two HF Antennas One Feedline  
by VK3HOT on September 10, 2007 Mail this to a friend!
Great article, I guess a lot of us who sit and think whatif? will now get out there and try it and see what happens. I admit to thinking what if I added a wire to the feedpoint of my Diamond HF Vertical, just for fun, who knows, I might actually make it out past the back fence for a change!!

Good luck with it.
Simon
 
RE: Two HF Antennas One Feedline  
by W6TH on September 10, 2007 Mail this to a friend!
.
W4LGH Alan,

You must remember that all of your boat anchors had a built in antenna that tuned from 25 Z to 600 Z impedance, this was called a tank circuit and was a pi network tuner. Could tune an antenna that was mis tuned.

.:
 
RE: Two HF Antennas One Feedline  
by W6TH on September 10, 2007 Mail this to a friend!
.
W4LGH Alan, Correction on a mis type.
......built in antenna tuner that tuned from........

You must remember that all of your boat anchors had a built in antenna tuner that tuned from 25 Z to 600 Z impedance, this was called a tank circuit and was a pi network tuner. Could tune an antenna that was mis tuned.

.:
 
RE: Two HF Antennas One Feedline  
by K8MHZ on September 10, 2007 Mail this to a friend!
An antenna that was mis tuned?

OK...
 
RE: Two HF Antennas One Feedline  
by N2VIN on September 10, 2007 Mail this to a friend!
I use a 4:1 balun with a 65' and 35' wire on the transmission side and about 8 radials cut for different bands on the ground side. Radials are in my attic. It is easy to notice the improved reception with this setup. I also have less than 1.5:1 SWR on all bands but 80 WITHOUT a tuner. I realize that power will be split so I bought a 200 watt FT2000D to provide a little extra power.

I also notice that I DO have NULLs. Some stations will not hear me that are picking up hams all around me. Other times I believe that the two wires combine to produce strong lobes as I am able to be heard better with two wires rather than one when I experimented by removing one while working the same stations. I also believe that the 30-35' wire is the reason my SWR is completely flat on 20m without a tuner. That is the band I work 90% of the time so that was my goal in trying various arrangements.

Is this a fan dipole or is it more of an unterminated wire V? Could it even be an off center fed Windom type of antenna? I do not know and no one has been able to tell me. Basically it stated as a random wire and found that when added a second wire to my existing one, receiption of signals inceased two S meter points with a low noise floor. I have experimented with DX stations and went from hearing them fine to not hearing them at all or very weakly when I removed the second (shorter) wire.

All I know is that with the exception of 80 meters I can jump from band to band without worrying about tuning and do good when prop is good and even work some weak stations when conditions are poor. My observations and logs show a pretty direct correlation between the the signal strength of the receieved signal with that of my transmitted signal. By that I mean that if I hear a station at 57, I usually get the same report when they are being honest. In cases where the DX station is exceptionally strong due to very high power and beams they are about two S points stronger than me at most at 59.

I know that I am sacrificing a good omni directional pattern and some power in return for all band transmitting convenience and improved reception. In my way of thinking, so what if I get an 57 instead of a 59. It is like drowning in 20 feet of water instead of 100. In either case the result is the same. But gosh, with some wire in a tree and a balun and I can talk to the world without the aid of an antenna tuner Now that's entertainment and luck. :)
 
Two HF Antennas One Feedline  
by VE3TMT on September 10, 2007 Mail this to a friend!
"Boy,

It sure didn't take long for this thread to go to hell in a handbasket."

You're not surprised are you Rick?
 
Two HF Antennas One Feedline  
by KU2US on September 10, 2007 Mail this to a friend!
Thanks to everyone: A lot of info to digest. A little bit more information to ponder over: First, by my observation, 40 meters seems to be the band the system works on the best. I measured the feed line from the "T" connector to my shack and it appears to be approx.+/- 1/4 wavelength of 40 meters. About the remark about the "cluelesss newbies and clueless older hams". If they experimented a little bit they would not be so clueless would they? Thats why I posted this, to learn something, and I have!!...Even after 29 years of being licensed. I tried the antennas separately on a coax switch. It appears that the G5 heard better because of its height but was noisier. The 5BTV ground mounted was quieter and had less recieve signal strength-This I like better because I have a pre-amp to compensate. BUT together, I do hear better with less noise than the G5 but more noise than the 5BTV? go figure-somewhere in the middle. I know that polarization is meaningless for long distance HF at the DX recieving end. That cancels out the vert.polarization vs. the G5 horizontal Polarization, but not for short distances, where the G5 is probably a better performer. I know that there are a lot more factors involved, but thats the beauty of this "thing"-the 2 antennas were put up, connected and somehow work together OK, at least for me. I am so suprised that there are almost non-existant flames? This is NOT an invitation. Great responses-Thanks, Ken..
 
RE: Two HF Antennas One Feedline  
by WA7TUE on September 10, 2007 Mail this to a friend!
Since one antenna is vertical, and the other is horizontal, would there really be a phasing issue? I know that when the moonbounce antennas or satellite antennas use both polarizations, they either use a phasing line with like a 90 degree phase difference, or they use a relay arrangement to select one or the other, but could the equal length line to both antennas be providing the proper arrangement?
Also, as far as SWR goes, a lossy line, or one that is long enough will present a reasonable SWR to the xmitter, even though it is not reality.
Just points to consider....
Karl
Wa7Tue
 
RE: Two HF Antennas One Feedline  
by KU2US on September 10, 2007 Mail this to a friend!
To VK3HOT..Simon: I added a 1/4 wavelength wire to my 5BTV for 17 meters..It Works Great. Connected the top of the wire (Insulated from) to the top hat, ran it down to the bottom of the antenna, and connected it to the actual metal of the antenna, spacing it about 6 inches away from the antenna verticaly.. There are mods on the net for giving verticals more bands doing it this way. I bagged 3Y0X with it-100 Watts! You can do this for any band, if you have the physical antenna length. My next project is adding a 1/2 wavelength 6 meter wire..It should work OK...Ken
 
RE: Two HF Antennas One Feedline  
by ONAIR on September 10, 2007 Mail this to a friend!
This is a great idea. I wonder how much my receive and transmit could improve if I used 20 antennas on one line!
 
RE: Two HF Antennas One Feedline  
by W8JI on September 11, 2007 Mail this to a friend!
I have a mobile rig in my truck with 400 watts or so output. I've worked Europe on SSB, and as far as VK6 on SSB. On occasion I can beat several other fixed stations through on pileups. Now I could walk away with a fat head thinking "wow, that mobile antenna really works. I can work DX one call, and beat others in pileups." I could find someone, and there are many people, who are weaker than my mobile signal and focus on how much better than their kilowatt and big antenna my antenna works.

But then there is the real world where I know for a fact the antenna is less than 1% efficient on 160 and 20% on 80. It is lucky to make 35% efficiency on 40, and certainly several dB weaker than a clear high dipole at any distance.

It isn't that my mobile works super and I am superman, it's just that whatever I'm comparing it to either is a very crappy system or I am very lucky and happen to be in the right place at the right time.

Most of the fasinating stuff we hear about antennas is just emotional nonsense.

The resulting pattern of combining any two antennas together is simply the vector sum of the radiation from each antenna in any direction. We are simply phasing two elements together except in many cases we didn't plan anything, the result is just entirely random.

The efficiency is never better than the efficiency of the best of the two. It is always somewhere between the efficiency of the best antenna and zero. It can be worse than the worse by itself, but never better than the best.


For any direction and angle where signals are improved, there WILL ALWAYS be other directions and angles where signals are worse. The more we improve it in one area or areas, the weaker it will be in others.

That's always the way it really works when we put the emotion and lies aside. My $3000 six element 56 foot long boom 20 meter Yagi is exactly 8.8 dB stronger than a $12 wire dipole at the height and location in ONE direction. In all other directions the dipole is much stronger, unless I turn the beam.

If you want to read about how emotions affect antennas, read about my A-B tests of a dipole and a G5RV. When I told people the G5RV was a dipole, it was stronger than the dipole I said was a G5RV. Whene I called the G5RV a G5RV, it was weaker. No change in the antenna, only in what I told people.

 
RE: Two HF Antennas One Feedline  
by K9IUQ on September 11, 2007 Mail this to a friend!
W8JI:
Most of the fasinating stuff we hear about antennas is just emotional nonsense.
........................................................

I wish this line was put in EVERY Antenna Book.

Stan K9IUQ
 
RE: Two HF Antennas One Feedline  
by K0BG on September 11, 2007 Mail this to a friend!
Stan (and Tom), Amen again!

My amusement on this subject has almost turned into a peeve. The number of DX contacts worked, or the fact you can work anything you hear, has no correlation to gain, efficiency, capture area (another peeve), or any other antenna parameter including SWR. They are amateur myths in more ways than one (pun intended)!

Alan, KØBG
www.k0bg.com
 
RE: Two HF Antennas One Feedline  
by W6TH on September 11, 2007 Mail this to a friend!
.

I work all hams by the formation of a mental image of something that is neither perceived as real nor present to the senses.

W6TH

.:
 
RE: Two HF Antennas One Feedline  
by N3OX on September 11, 2007 Mail this to a friend!
"My $3000 six element 56 foot long boom 20 meter Yagi is exactly 8.8 dB stronger than a $12 wire dipole at the height and location in ONE direction. In all other directions the dipole is much stronger, unless I turn the beam"

And any of us can easily verify that (maybe to a less than stellar but better than guessing degree of accuracy) with a smoothly operating antenna switch, a step attenuator, a receiver, and either a stable signal source a few wavelengths away or many, many trials switching back and forth on skywave signals. We almost all have those things already except perhaps the step attenuator.

Is that what you did KU2US? If not, it would make for a VERY cool article if you took some hard data on your setup. Of course, you need an A/B/C G5RV/Vert/both switch...

We don't all have to put hours of engineering into our antenna systems, but it's always a good idea to be as scientific as possible about our interesting results.

It sounds like you're quite satisfied that the combo antenna is best for what you're doing.

I doubt any of us can model your system... too many environmental factors especially considering a ground mounted vertical...

So if you want to know WHY it's working how it's working, do some A/B/C tests with a step attenuator inline on incoming signals and note the results in different directions.

You might find that a null on Europe gets filled in on 20m and that's why you like the antenna so much.

You might find that you got really, really, really lucky and you have a local diagonally polarized noise source in just the right direction that your combo antenna is cross polarized to it.

Anyone else who wants to start sticking antennas together needs to know WHY your random combination works better... and I think you're the only one who can get that information.

We're all free to speculate, but none of us are going to be right...


...except maybe those who are saying that it's just that the antenna makes you feel good, but that can be a a USEFUL and powerful thing in the pileups as long as the random combo antenna isn't particularly poor compared to either antenna by itself. A lot of making tough contacts is believing that you can do it, having good timing, and persisting, and if teeing your G5RV and vertical together keeps you in the chair longer in a tough pileup, that antenna is a winner ;-)

73,
Dan
 
RE: Two HF Antennas One Feedline  
by N4CQR on September 11, 2007 Mail this to a friend!
K0BG The number of DX contacts worked, or the fact you can work anything you hear, has no correlation to gain, efficiency......


Several years ago, 96 or 97 I guess it was, I worked many JA, VK HK and so forth on 10 meters with a 8' whip stuck in a chain link fence.
Today, with a Mosley Clasic 33, I can't even hear them but rare occasions.

There is a reason for this but it seems to have been tossed aside in light of other conventions and circumstances.

Toodles..
Craig :)
 
RE: Two HF Antennas One Feedline  
by K1CJS on September 11, 2007 Mail this to a friend!
Well Ken,

You commented on it and it came. One is peeved now, others gives sarcasm. I think those people have lost sight of the fact this is a hobby. Even if ham radio is the only reason they're out there now, these people should realize some others prefer to experiment and find out ON THEIR OWN. I always thought elmers gave encouragement and helped others along on the path to knowledge. It seems that these e-Ham 'elmers' uses the sledgehammer on a plate glass window approach to get to the results. No encouragement or guidance, just criticism and ridicule.

I know that if I didn't want the fun and wonder of discovery I would go to whatever classes was needed to get just the facts. Some of these e-Ham elmers should smarten up and let us knowledge seeking types rejoice in our so called discoveries instead of shooting us down.

To you 'elmer' types: Have you really forgotten how things were when you were in our position--finding out things for yourselves? Maybe what is being said is true--there are no elmers left anymore.

73, Ken, and keep on experimenting--and having fun!
 
RE: Two HF Antennas One Feedline  
by N3JBH on September 11, 2007 Mail this to a friend!
"I work all hams by the formation of a mental image of something that is neither perceived as real nor present to the senses. W6TH "

Is that why you ignore me? I simply want to be as good as you Vito. And being this is an elmers forum i am olny looking to you for elmering. Please do not ignor us Vito Please. Make us wise.

Jeff
 
RE: Two HF Antennas One Feedline  
by W6TH on September 11, 2007 Mail this to a friend!
.

N3JBH
"I work all hams by the formation of a mental image of something that is neither perceived as real nor present to the senses. W6TH "

Is that why you ignore me? I simply want to be as good as you Vito. And being this is an elmers forum i am olny looking to you for elmering. Please do not ignor us Vito Please. Make us wise.
...................................................

Jeff, evidently you did not understand what I had written, where as one must ignore the ignorant. Therefore I must break through traditional teachings to truth and the word of life.

W6TH

.:
 
RE: Two HF Antennas One Feedline  
by KB9CRY on September 11, 2007 Mail this to a friend!
I think those people have lost sight of the fact this is a hobby.

Yes it's a hobby but it's also a scientific one that it set in scientifically provable theories and facts.
The "true" experimentation was all done in the past, except by Art and his friend Gauss.


these people should realize some others prefer to experiment and find out ON THEIR OWN.


Yes they are and they do and should.


I always thought elmers gave encouragement and helped others along on the path to knowledge.

No, back in the past you maybe had one or a few Elmers who themselves had some experience in certain areas and some knowledge. Now you have the Internet and this reflector; you are now suddenly connected to hundreds of Elmers and much more experience and knowledge.


It seems that these e-Ham 'elmers' uses the sledgehammer on a plate glass window approach to get to the results. No encouragement or guidance, just criticism and ridicule.


I don't condone the criticism nor ridicule, but when we see someone going towards the cliff of no return or attempting to explain a newly found theory that is false, yes many do just like your parents did when you were very young. They just say No. Usually they give the reason but no encouragement to play near the cliff is given.



Hey you can find out all the things you want on your own; just remember that when you publich them hear on the public forum, you'll get the responses. You have to be strong enough to understand that others may have more knowledge and trust them. If they say No, take it and work from there.


To you 'elmer' types: Have you really forgotten how things were when you were in our position--finding out things for yourselves?


Yes, and if I had access to eHam back then, I wouldn't have even strung up the 10M dipole 10 ft off the ground across the back yard. And, I would have obtained an amp a lot sooner and not messed around with noise reduction filters.

 
RE: Two HF Antennas One Feedline  
by W6TH on September 11, 2007 Mail this to a friend!
.
KB9CRY

Way back, when I was a youngster, We the People could trust our Federal Government, not any longer, can we?

What more can I say, even to mention ham radio, ham radio was also trustful back then as well.

As far as Elmers, plenty around to seek, but ham radio is now a government of its own. We had Elmers back in my day and it was called "The Radio Amateurs Handbook".

Seek and ye shall find.

W6TH

.:
 
RE: Two HF Antennas One Feedline  
by N3OX on September 11, 2007 Mail this to a friend!
"Some of these e-Ham elmers should smarten up and let us knowledge seeking types rejoice in our so called discoveries instead of shooting us down. "

I don't think anyone is shooting KU2US down, per se.

A lot of people on here know that if you phase a couple of antennas together randomly, the results are undesirable, both in theory and in practice.

A lot of people on here also know that a lot of antennas that are deemed "better" than another configuration are done so without making a single objective measurement.

- - - - - -

Now, it *IS* just a hobby, and you shouldn't have to make objective measurements on everything you do in ham radio if you don't want to.

However, if you write an eHam ARTICLE laying out your experimental antenna and make claims that it's better based on subjective observation, this is what happens.

The Hammer of Technical Guys comes down.

I think that some of them should probably soften their edges a little bit... (maybe me too?) but it's better for all of us if someone asks "why does my weird antenna work as well as it does" and a bunch of people say "I doubt it does, have you measured it?"

It might seem harsh, but it's the right response.

An antenna ARTICLE on eHam that doesn't pass technical muster SHOULD get criticized.

Even if the tone of an ARTICLE is "hey, guys, what do you think of this," the material in the article is still going to be seen by many as holding more weight than a question asked in the forums.

Some people are going to try this because it's in an article on the front page. I say to them, don't waste your time unless you're doing it for pure curiosity.

Not because I'm 100% sure KU2US's antenna doesn't work for him. I believe it might... but I also believe there are so many variables in this installation that it's not worth trying to reproduce.

And, if anyone wants to reproduce it because they're curious, they should go in ready to objectively assess what they find, because the power of our expectations can really cloud the objective reality of an antenna system.

I think it's an interesting article, and I'm glad it's here, but the ensuing comments suggesting why this sort of thing almost never works in your favor are an important part of the whole picture.

Dan




 
Two HF Antennas One Feedline  
by KB2NAT on September 11, 2007 Mail this to a friend!
Ken, Thanks for adding an interesting article. Sorry for the comments that could tell you everything but what you were interested in. In the '70's, during the CB craze, I set up a mobile vertical with a wire dipole cut to 11 meters. Together, they worked far better than individually. The mobile vertical had no ground system of consequence, but what did I know? The result of using both together was an amazing jump in the transmitting/receive range (The antennas were both in an inclosed porch on Cayuga Lake in upstate NY). Maybe I was "lucky", too, but it sure was fun and OBVIOUSLY better. If I moved the wire antenna around performance decreased hugely. Still not claiming to know much, I wonder how they effected each other's performance by proximity effect. But whatever, it was fun and now that you've reminded me, I'm looking forward to doing this again sometime.
Rick, KB2NAT
 
RE: Two HF Antennas One Feedline  
by W6TH on September 11, 2007 Mail this to a friend!
.

In my opinion, "IF" the G5RV was not set and used as a inverted "V", but horizontal, then properly phased with the 5BTV, it is likely that a good comparison could be estimated as to performance.

Crap like this is often pulled on eHAM by our professionals; 0dB = .214 dBi, well for today it can be seen that, 0dB = .214 dBi is = to 2.14 dBd.

How is this for a starter?

W6TH
.:
 
RE: Two HF Antennas One Feedline  
by W8JI on September 11, 2007 Mail this to a friend!
Several people made great suggestions about how to do an actual meaningful experiment. There were several suggestions that would improve ability to learn or improve skill!! What great spirit!

Unfortunately the suggestions also involved pointing out someone was not correct, and so the suggestions crossed the politically correct line of "anything anyone says or does is wonderful".

In 1970 an Elmer could point out errors or problems and was even allowed to suggest how to improve things.

Today a proper Elmer just says "My that's wonderful." They say that no matter how poor the experimental method or how utterly meaningless the conclusion or evidence.

This is why what used to be the greatest most innovative nation is now falling behind the rest of the world in skills and ethics. We can't admit an obvious mistake is a mistake, we can't have a critical honest look at ourselves.

We are, by default, not allowed to advance or learn anything. We are not allowed to be critical when criticism is called for. It is politically incorrect to be honest. The only correct action is to be cheerleaders.

Elmering is dead. Long live the Cheerleader.

This is true in politics and on E-ham.
 
RE: Two HF Antennas One Feedline  
by N6AJR on September 11, 2007 Mail this to a friend!
well folks, here we go again..


First , this is a hobby, and a good hobby at that.



Second, any antenna is better than no antenna at all.



Third this is internet about ham radio, not ham radio.



They must have laughed at UDO/Yagi when the beam was first presented. There are a zillion ways to make an antenna radiate, from that fellow with the frqactal antenna, to the dipole to the fan dipole ot g5rv's in all of its varients, to beverages , and those wonder antennas like a slinky or the one with a 3oo watt 50 ohm resistor at the feed point, and 4 squares and so on, don't forget about the Isotron series. They all work to some extent or another.



The best antenna is really dependent on what you are doing with it. If you have CC&R's a flag pole vert is the best antenna. If you have a hundred acres in the middle of no where, a set of 4 two hundred foot towers with yagis and wired as a 4 square on 160 is the best antenna.



A 5 element beam on 80 may be your cup of tea, but it is not worth a darn as a EME antenna.


So What is the "best antenna", why the one that works for you.



So if you really need an Elmer , for a specific problem, send me an email and I will add what little I know from my experiance. Youknow where QRZ is.



I try to help folks, but sometimes my methods are not the best for you, but there is also the other Tom and Alan, and Steve and many more here, and we all do what we can. If you live near, come on over and play, and ignore those on the internet with a poor attitude.



Remember the first rule of antennas,:



ANY ANTENNA IS BETTER THAN NO ANTENNA AT ALL

 
RE: Two HF Antennas One Feedline  
by N3OX on September 11, 2007 Mail this to a friend!
"ANY ANTENNA IS BETTER THAN NO ANTENNA AT ALL"

But the differences between any two antennas can range from profound and obvious to fraction-of-a-dB subtle.

Once you get above the NO ANTENNA level, sometimes you want to be a little more careful ;-)

Dan



 
Two HF Antennas One Feedline  
by KC8ZEV on September 11, 2007 Mail this to a friend!
In the old days, the test and measurement equipment wasn't as common as what is available today. Trial and error, "what if?" experimentation based on (hopefully) some basic theory was fun. Pehaps the old boatanchors were a little more forgiving than the $$$ rice boxes that rule the roost today. With a "tuner" (matching network really) in line, one feedline with 2 antennas probably won't cook your rig, but since the tuner is tricking your transceiver into thinking everything is great out in antenna land, the double antenna system is nebulous. True, it may have some unique charecteristics, but without some decent test & measurement equipment, it may be hard to duplicate based on trial and error. If it works great, I would want to know why. But perhaps that is the "clueless newbie" in me.

73
KC8ZEV
 
RE: Two HF Antennas One Feedline  
by KB9CRY on September 11, 2007 Mail this to a friend!
Vito, that's also the only Elmer I ever had. I did a lot of reading and then even more so before I ever put a signal out on the air.

My personal progression was fairly rapid but looking back, I could have skipped a lot of steps if eHam and you all had been available back then.

Tom, your insight is spot on. These days you don't want to get anyone's feeling hurt by calling them out that they are headed for the cliff. I guess we ought to just cheer them on and watch for the splash at the bottom.

 
RE: Two HF Antennas One Feedline  
by K1CJS on September 11, 2007 Mail this to a friend!
KB9CRY wrote:

"The "true" experimentation was all done in the past, except by Art and his friend Gauss."

Here, I have to disagree, unless you mean on antennas alone--in which case you're probably right.

"I don't condone the criticism nor ridicule, but when we see someone going towards the cliff of no return or attempting to explain a newly found theory that is false......."

I agree that letting people know when they're going off course should be done, its just the manner in which some of the people here do it that is problematic.

"Some people are going to try this because it's in an article on the front page. I say to them, don't waste your time unless you're doing it for pure curiosity."

Here, I agree wholeheartdly. But unless you a complete newbie and don't know squat about RF antenna theory and construction principles I doubt you would just go out and try to duplicate Ken's setup.

"Not because I'm 100% sure KU2US's antenna doesn't work for him. I believe it might... but I also believe there are so many variables in this installation that it's not worth trying to reproduce. I think it's an interesting article, and I'm glad it's here, but the ensuing comments suggesting why this sort of thing almost never works in your favor are an important part of the whole picture."

True. However, how the comments are offered can change the meaning of them in some instances. Here you have one person who is peeved and said as much. Others offered off the wall comments that come across as ridicule, and still others who are talking down to Ken as if he doesn't know anything compared to those who asked questions and agreed with some of his conclusions.

Above all, Ken was asking for help! He doesn't understand why the antennas were working so well. He got some very thoughtful positive comments and almost as many rediculous smart aleck remarks about what he tried. Cut those of us who want to find out why things work--or don't work--some slack. We wouldn't be asking if we didn't want to find out--but keep in mind that we may know more than it seems we do.
 
RE: Two HF Antennas One Feedline  
by AI4IT on September 11, 2007 Mail this to a friend!
My Antron 99 was struck by lightening while I was trying to hold it during a storm to ground it. I recently recovered from severe burns, but I learned a lesson: I should have held the antenna with both hands, not just one. HUH?
 
RE: Two HF Antennas One Feedline  
by W8JI on September 11, 2007 Mail this to a friend!
KC8ZEV,

It is possible to determine which of two antennas or antenna configurations is better with hardly any equipment at all. One method was already clearly outlined here.

All it takes is an S meter and a switch.

If you want some really meaningful numbers it would be necessary to add a calibrated step attenuator pad to the mix.

That would cost all of $100 to the appliance operator.... or a few bucks to a builder and scrounger.

There really isn't any defending or defense for using "feelings" when comparing something like antennas so long as a person can have two systems in place at the same time.

I honestly can't imagine anyone deciding something works better without the ability to compare back and forth to a reference point of some type.

Let me give a specific example...

When I was 12 years old I had an 807 on a peg board chassis for a transmitter. I went down the road bragging to a Ham about my new antenna. Fred told me I was wasting time blowing smoke at him. He told me I couldn’t really tell a thing without changing between both antennas and watching an S meter or listening to the signal level. He explained it would be about the same for transmitting and receiving.

I went home and pounded three nails into a hunk of 2x6 wood. I bent a hook in the coax center conductor from my rig to that board, connected all the shields with wire to one nail. I used the remaining two nails as terminals for the two antenna feedlines.

By nailing the board vertical I had a gravity held switch, and I found my new antenna was not nearly as loud as the old antenna when I listened to dozens of signals.

That single experiment meant significantly MORE than my recent change of antennas. I just removed one antenna and replaced it with a bigger antenna much higher, and I can't tell a darned thing. I "feel" better about my new antenna. I "feel" it is "quieter". I "feel" the signals are better. But I don't know a thing for sure. I honestly have no idea if it is better or worse, and I never will. I never did a reference test.

Even if I only had a 2x6 with three nails and a simple reference dipole that I compared to the old antenna and the new antenna to the dipole with many signals over time watching an S meter and writing it down, I'd know absolutely for sure which antenna was better. I wouldn't need fancy test gear.

The real problem today is getting people to quit making excuses for useless methodology and to start thinking about solving problems or about what they are doing. I never got mad at Fred for telling me to ride my bike back home and compare the antennas, but as a kid or adult in 1990 or later I probably would have made an excuse why I couldn’t do what I did with a board and three nails and considered Fred a “bad Elmer”.

Times have changed, and not for the better.



 
RE: Two HF Antennas One Feedline  
by W6TH on September 11, 2007 Mail this to a friend!
.

No need for the nails as one can use the iambic paddle for a switch, those that don't use code, but have a paddle sitting on the table, regardless.

.:
 
RE: Two HF Antennas One Feedline  
by KC8ZEV on September 11, 2007 Mail this to a friend!
W8JI,

Indeed, determining which antenna performs better is a rudimentary excercise that could easily be determined with no test & measurement equipment at all....a switch and a S meter. If one is content with this determination, go work some HF DX, the experiment is over. However, some will go on and ask the key question here, WHY??? Why does antenna A perform better than antenna B???? A S meter and a switch won't help much here. I need to know some impedance figures, a Bird wattmeter would be most useful as well. Field strength measurements when both antennas are in operation v.s each one would also be useful data. Antenna modeling should also be performed. Antenna analyzers can save you a few steps with the pencil and paper as well as many software applications. Figuring out which antenna is better is one thing, figuring out WHY two antennas do what they do together is another. Test and measurement equipment is a key component to obtaining data that would help answer the question. Am I advocating every Ham to fill the shelves above their test bench with every piece of equipment made by
HP, Rohde & Schwarz, Tektronix and Fluke??? No, the average Ham would find that far too cost prohibitive.
But, without a doubt, good measurement equipment is required to answer the "why" question. It is all in the numbers. Some say it is better to be lucky than good. Luck is nothing more than random chance. Crunch the numbers to find out how to be good. Gotta have the right tools for the job.
Besides which, all that test & measurment equipment looks really cool in the shack!!!

73
KC8ZEV
 
RE: Two HF Antennas One Feedline  
by W5HTW on September 11, 2007 Mail this to a friend!
This antenna system is not unique. This particular one happens to be by chance rather than design.

First, look at the fan dipole, already mentioned. This is actually the same thing - several antennas on a single feedline. In this case, the resonant antenna on a particular band presents the best match to the transmitter output, and thereby accepts the maximum RF. A matter of a tuned circuit, in parallel with other circuits that are not tuned.

Secondly, look at the log periodic. This again, is the same principle of multiple antennas in parallel. One simple version is the VHF TV antenna. A lot of elements, tuned for multiple TV channels over an extremely wide overall frequency range.

Now suppose one had a horizontal 80 meter dipole, and a vertical 15 meter dipole, both fed with the same coax. What happens if one tries to operate on 30 meters? Nothing is resonant, and nothing works. If, though, one operates on 80 meters, the 15 meter vertical becomes 'invisible' to the transmitter output. It just "isn't there." So it has no affect.

On receive, though, it may serve to lower overall performance of the receiver.

Diversity reception has been in use for many decades. Ideally in true diversity reception, two antennas are fed, through a coupler, to a single receiver. The antennas are matched, are tuned for the same frequency, and are separated by distances of approximately 1,000 feet. That is because as the propagation varies moment to moment, at least one of the antennas will likely be in the "skip zone."

In dual diversity, the difference is two receivers, each fed by a different antenna, are tuned to the same frequency, with antennas 1,000 feet apart, and receiver outputs combined. Going further, even frequency diversion is used, with recievers receiving signals on two different frequencies.

Diversity transmission is also not at all unheard of, but it is a much different animal to put ONE transmitter on two or more antennas. That is, without a phasing network! Then it is done all the time in AM broadcasting, with phase shifting networks in directional systems, and it is done also in FM broadcasting, where it is even easier! In fact, many FM stations are rated at both Horizontal and Vertical polarization, by feeding two antennas of different polarity. Since FM broadcast stations are rated at ERP, rather than direct RF power output as hams are (with the exception of 60 meters) even dividing the power, still reslts in a high ERP in each polarity. And it may intentionally not be equal! The station may radiate more vertical RF than horizontal, for example, but the bottom line is still two antennas fed in parallel, and NOT in phased arrays.

The bottom line on this original posting is that each of the antennas will present a different load to the transmitter, at different frequencies, along the same lines of how a log periodic works. I don't see any reason it would NOT work, except that both antennas are multiband. That presents a matching problem, but beyond that, not uncommon.

Part of the reason, in fact probably the main reason, diversity transmission (one transmitter, multiple antennas) is not used is indeed the division of power. With the antennas matched, in a two antenna system, each gets half the power. But the matching has to keep changing with changes in frequency.

In a hypothetical setup, a 1000 watt transmitter feeding two matched antennas, one vertical and one horizontal, for example, it defeats the purpose of reaching a specific destination, since it cuts the power radiated in that direction/polarity in half. Chances are the distant station would not receive signals from each of the two antennas equally. So signal sentto one would be simply wasted.

It would not be impossible to feed two very separated antennas with a single transmitter, in reverse diversity transmission, but the goal of doing so would be questionable.

Ed
 
RE: Two HF Antennas One Feedline  
by KC8ZEV on September 12, 2007 Mail this to a friend!
W5HTW,

Outstanding post!!!!

It is all in the numbers!!

73
KC8ZEV
 
RE: Two HF Antennas One Feedline  
by W6TH on September 12, 2007 Mail this to a friend!
.
Like I posted, the diversity system I used is the best test.

I can now tell one and another true facts of the condition of each antenna and its performance as to which is the better antenna, although the post will take quite a few pages to define the purpose and results of each.

Therefore, to prevent an aggravated assault, which can happen on eHAM, I will not disclose this information at this time and look forward to a more future time to benefit one and all.

73, W6TH

.:
 
RE: Two HF Antennas One Feedline  
by W4LGH on September 12, 2007 Mail this to a friend!
While yall are battling this out, as theory says it should not work, remember that most GREAT inventions were discovered by accident! And a theory is just that, it is neither proven or disproven, just generally accepted as the way it is. Many theories have been disproven in recient years.

Antenna theory can be argued until the cows come home, certan things we know that work, but I bet there are of lot of un-discoved antenna properties
that will be found in recient years.

73 de W4LGH - Alan
http://www.w4lgh.com
 
RE: Two HF Antennas One Feedline  
by K1CJS on September 12, 2007 Mail this to a friend!
Vito,

You continue to make your claims of knowledge on this and other threads, then refuse to post that so called knowledge. Several pages? I doubt that. If so, it's several EMPTY pages--from an empty mind. Have a nice day.
 
RE: Two HF Antennas One Feedline  
by N3OX on September 12, 2007 Mail this to a friend!
"While yall are battling this out, as theory says it should not work,"

An application of electromagnetic *theory* to this antenna system will EASILY model what it does.

The trick is to build a sufficiently sophisticated model. ... but we're not talking rocket science here, we're talking a few hours of work with NEC2 and a couple more hours of measurements to phenomenologically model the effect of, say, the vertical's connection to earth.

Even if this antenna does work really, really well at KU2US's installation, it's NOT because it doesn't obey Maxwell's laws!!

Those of us who think it doesn't work aren't saying "Electromagnetic Theory Says This Antenna Don't Work", we're saying that in general, hams want pairs of antennas phased together that have some particular spatial arrangement and the same polarization....

And that, in general, if you phase a ground mounted vertical and a horizontal doublet together without considering impedances and what you actually want to DO with this antenna, you shouldn't expect the combination to work better than either of the single antennas.

It's just a warning to others that KU2US's result is not going to be generally applicable, if indeed KU2US has any result at all.

Which brings me to:

" remember that most GREAT inventions were discovered by accident!""

Many great discoveries were made by people who found an unexpected result in something they were doing or looking at, and then spent time and effort characterizing it so they could at least try to DESCRIBE THE BEHAVIOR FULLY.

Then, armed with a full, detailed description of the "discovered" behavior, you can go on to try to explain it.

Sometimes, in the process of scrutinizing a system, you'll come up with a negative result.

If someone wants to build this and drive around it taking field strength measurements of the G5RV alone, the vertical alone, and the combination antenna using both horizontal and vertical polarization on all the bands, then maybe we can get somewhere toward deciding if this is a discovery or just an antenna that makes someone feel good.

I decided to stop writing for a second and try A/B/C on my Moxon, a vertical and the combination (easy to do with an Ameritron antenna switch... position 1, position 2, short together 1&2 to close both relays simultaneously)

So far I haven't noticed a single dramatic thing about it. If there's a very strong signal on one antenna that's very weak on the other, they're still pretty strong on the combination (big + zero = big)

If there's a loud local noise on the band that's off the back of the Moxon, mixing in the vertical certainly degrades the S/N

Signals that are copyable about the same S/N on both antennas stay about the same when I mix them.

Here's the model result. The vertical and Moxon and the Moxon's feedline are all included (the Mox feedline has a choke just like the antenna does, so the pattern remains clean). Total power is divided about equally between the antennas in this picture, which I certainly don't expect.

http://www.n3ox.net/files/combining.jpg

Which antenna would YOU use?

By the way, my combo *also* manages to give a decent SWR by accident on 20m. Nice and flat, maybe 1.3:1 with the 1.5:1 Moxon and the 2:1 vertical.

73,
Dan























 
RE: Two HF Antennas One Feedline  
by K1CJS on September 12, 2007 Mail this to a friend!
Alan, W4LGH:

You are oh, so correct. Quite a few discoveries were made by accident. It seems the key to making them is not to ask for any guidance or information here on e-Ham. All you get from the 'learned gurus' here is discouragement.

The value of this site to the ham radio community has dropped markedly recently. Its almost to the point that amateurs would be better off on their own. A lot of people who used to frequent this site have stopped doing so, and more will follow. Its really too bad--but that's the result of the way everything is going these days.

I certainly hope Bill Fisher can't see what this site has become.
 
RE: Two HF Antennas One Feedline  
by W8JI on September 12, 2007 Mail this to a friend!
Let's get a few facts on the table:

1.) Antenna theory is already very firmly established. Most was back back in the 1800's, and the fine tuning and details were handled in the 1900's. No one is going to suddenly discover an error or warp in the rules by screwing around with a wire in the back yard, and it won't happen in a lab either. The only thing that can happen is the details of a general rule might expand to a finer detail, but everything will all work the same and follow the same rules as in 1950's Physics or electromagnetics courses. Let's not pretend antennas are black magic or voo-doo or we don't understand the behavior or interactions of charges. That's just silly.

2.) When we combine two antennas the resulting pattern is the vector sum of the two patterns at any pioint in space. You don't get "diversity" by directly mixing two antennas. It just does NOT happen. It doesn't happen at microwave, it doesn't happen at HF.

Diversity requires TWO or more receivers on TWO or more antennas, and some "smart" way of combining the detected signals. It is absolutely impossible, outside of a Ham article or advertisement, to obtain diversity by mixing signals in an antenna.

3.) You can't transmit single frequency diversity without a link back from the receiver to select the best transmit antenna. Feeding two different antennas doesn't work as diversity. What you get is a mix of the two patterns which results in one pattern that is different than either of the two original patterns.

If you do a proper circular system with reasonably proper phasing, you can launch a time-rotating wavefront. But slapping a dipole and a vertical together through a T connector, unless you are the luckiest guy in the world, won't produce anything but a plane wave of fixed polarization. In any single direction there will be almost no circular rotation, it will just be a wave of a certain angle and 90 degrees from that angle will be a null.

4.) An unused antenna does NOT look invisible unless through dumb luck or careful planning the unused antenna appears as an open circuit at a feed junction. The log periodic is NOT a series of random accidents, it is a carefully planned group of cells that reflect proper impedance back up a planned transmission line tio a feedpoint.

A fan dipole isn't an unplanned group of dipoles or verticals randomly tied through different feedlines to one point. It is a planned system where similar antennas are connected to one junction WITHOUT transmission lines between those dipoles and that common junction. Throw a transmission line in, especially a random one, and things fall apart.


When someone happens to throw a few random things together and it happens to work after some fashion that pleases the user, it's more a matter of random luck or not being too critical of results that produces a happy outcome.

That isn't "discovering" anything and it won't lead to any new invention.

What most people fail to grasp is things like the Yagi were NOT discovered by accident. Any engineering textbook from the 1920's or 1930's onwards explains mutual coupling, and the theory was well established about phase shift in reactances long before then. The vector addition of fields was know hundreds of years earlier.

The Uda-Yagi (not Udo Yagi!) was created out of common knowledge readily available to fill a specific need someone had. The NEED drove the creation, the theory was already there.

All antennas are really this way. We have a set of problems or a particular problem we want to solve, and every tool we need to solve the problem is already there. We don't invent anything, we just apply things we know to solve a particular problem or need.

73 Tom







 
RE: Two HF Antennas One Feedline  
by N3OX on September 12, 2007 Mail this to a friend!
Just so people don't have to wade through my whole rant about Electromagnetics in response to W4LGH, I want to excerpt myself:

"I decided to stop writing for a second and try A/B/C on my Moxon, a vertical and the combination (easy to do with an Ameritron antenna switch... position 1, position 2, short together 1&2 to close both relays simultaneously)

So far I haven't noticed a single dramatic thing about it."

I would like to encourage KU2US to give some more details about the performance of his antenna system. Favored directions, etc.

Dan
 
RE: Two HF Antennas One Feedline  
by N3OX on September 12, 2007 Mail this to a friend!
W8JI says:

"Feeding two different antennas doesn't work as diversity. What you get is a mix of the two patterns which results in one pattern that is different than either of the two original patterns."

Yep. Also so you don't have to wade through my rant:

http://www.n3ox.net/files/combining.jpg

Dan
 
RE: Two HF Antennas One Feedline  
by N3OX on September 12, 2007 Mail this to a friend!
Oh, and K1CJS, if anyone's *discouraged* by the truth and established science, it's going to be very hard for them to make new discoveries.

 
RE: Two HF Antennas One Feedline  
by N3OX on September 12, 2007 Mail this to a friend!
Oh yeah, and one more thing:

"certainly hope Bill Fisher can't see what this site has become."

You think he would come up in here and tell W8JI to take a hike and stop discouraging people with useful facts?

Might wanna think on that one for a second.

Dan



 
RE: Two HF Antennas One Feedline  
by W4LGH on September 12, 2007 Mail this to a friend!
W8JI said..."Let's get a few facts on the table:
1.) Antenna theory is already very firmly established. Most was back back in the 1800's, and the fine tuning and details were handled in the 1900's. No one is going to suddenly discover an error or warp in the rules by screwing around with a wire in the back yard, and it won't happen in a lab either."

You see I have a serious problem with that statement. 1st problem is taking the stance that this is the way it is as it was in the 1800's.

The 2nd problem is, that a of stuff was well figured out in the late 1800's into the early 1900's, and many improvements and changes have been made in recient years. The ability to make an atmoic bomb was available in the 1800's, but no one thought of it.

So why is antenna technology any different? We've built new test equipment, we have CAD and CAM, we have all new ways of doing just about everything, so again I ask, why is antenna theory any different? New discoveries come out everyday disproving theories of the past 100 years.

So I can't say that antenna theory is the same as it was, I have a much more open mind to newer discoveries which will completely re-write what we always thought before.

If you always do what you have always done, then you WILL get what you have always GOTTEN!

Open up to progress! It might amaze you!

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


 
RE: Two HF Antennas One Feedline  
by K1CJS on September 12, 2007 Mail this to a friend!
By N3OX:

"Oh, and K1CJS, if anyone's *discouraged* by the truth and established science, it's going to be very hard for them to make new discoveries."

Dan, I'll shoot a hole in your 'theory' right now--and don't say anybody is compaing themselves or their thoughts to this, but Albert Einstein came along in the beginning of the twentieth century and redefined physics with his theory of relativity. Back then classical physics was truth and established science. Lo and behold--established science had to be redefined because relativity was closer to reality than classic theories were.

Who is to say someone won't come around and do the same thing now or in the future to radio and RF theory?
 
RE: Two HF Antennas One Feedline  
by K1CJS on September 12, 2007 Mail this to a friend!
N3OX again:

"Oh yeah, and one more thing:
"certainly hope Bill Fisher can't see what this site has become."
You think he would come up in here and tell W8JI to take a hike and stop discouraging people with useful facts?
Might wanna think on that one for a second.

Try reading all of the statement. I referred to how people use this site and how they act and post here. Not to W8JI's useful facts.

Comprehension seems to ba another lost art--right along side common sense.
 
RE: Two HF Antennas One Feedline  
by K1CJS on September 12, 2007 Mail this to a friend!
In particular, N3OX, I believe I was referring to people like you in my statement about Mr. Fisher. You mouth off like you know all when you haven't been around long enough to learn much of anything. Get you some experience before you succumb to foot in mouth disease--and learn how to spell. Its bureau, not buro.
 
RE: Two HF Antennas One Feedline  
by K1CJS on September 12, 2007 Mail this to a friend!
You wanna talk about standing science on its ear? Check out this article in the news section:

"Radio frequencies help burn salt water"

It seems like W4LGH, myself, and people who agree with us aren't all wrong.
 
RE: Two HF Antennas One Feedline  
by W6TH on September 12, 2007 Mail this to a friend!
.

See Dan, I told you several times that when you make a statement, it should be a mathematical analysis. Now who would dare to challenge you or even I?

If a "S" 9 signal is 45 dB, then it must be that a single "S" unit must be 5 dB. The proof is that when a signal is 10 dB over "S" 9, should be proof enough that one "S" unit is equal to 5 dB.

Years ago, we called dB dingleberries.

W6TH

.:
 
RE: Two HF Antennas One Feedline  
by W6TH on September 12, 2007 Mail this to a friend!
.
"Radio frequencies help burn salt water"

Nothing new to me as I always boiled my water in the microwave, to purify and remove the salt.

Makes for better coffee.

.:
 
RE: Two HF Antennas One Feedline  
by W4VR on September 12, 2007 Mail this to a friend!
Hmmm...let me see! I discovered 3 antennas by accident: the Inverted-T Ground-Mounted Vertical for 160 meters, the Upright-L for 80 meters, and the Co-phased Inverted Extended Double Zepp for 17. They all worked as expected.

Whenever in doubt about an antenna you discovered by accident, model the conglomeration on EZNEC or similar software and find out how it's performing before taking a wild guess. Better yet, model it and find out whether it's worth putting up.

Despite his academic qualifications and knowledge of physics and wave theory I'm sure Dr. Yagi did not claim victory on his antenna until after carefully modeling it in a laboratory or test range environment.
 
RE: Two HF Antennas One Feedline  
by N3OX on September 12, 2007 Mail this to a friend!
"You mouth off like you know all when you haven't been around long enough to learn much of anything"

Oh no, people know my birthday and all of a sudden I'm not allowed to talk to you big boys!

I'll go crawling back to my crib.

"Who is to say someone won't come around and do the same thing now or in the future to radio and RF theory?"

You already discount my opinions because I'm a mere 28 years old... but here's how I feel about this.

You *must* come up with something that CANNOT be described by the current theory, not just something that you haven't bothered trying to figure out with the current theory.

I only really get upset by people who blather on about how they've discovered something new and earth-shattering in antennas if they're trying to sell it, but the whole "misunderstood genius" thing is way overplayed in antenna circles.

And I am NOT picking on KU2US here. He never said he discovered something that was counter to the current laws of electromagnetics.

Nor did I suggest that the laws of electromagnetics preclude his antenna from working well or as he describes it.

The description is insufficient to come up with a good enough model, that's all. Measurements could clear that up, as could a good NEC2 simulation that included good enough data about the surroundings.

- - - - - -

I NEVER want to hear another antenna experimenter say that they've discovered something new about electromagnetic theory until they've exhaustively studied the antenna they've built in a quantitative fashion and come completely to the end of their rope in simulation and experiment.

Again, KU2US did NOT say this. But some of you guys are saying it FOR him and it's nonsense.

Any arrangement of coils, capacitors, current carrying wires, transmission lines and earth grounds has behavior that can be handily modeled by today's physics.

The only way you will ever convince me otherwise is with hard, quantitative data that I can reproduce on my own.

Mentioning Einstein or any other scientist who discovered something that required a rethinking of physical laws is not a allowable substitute for hard work in the current physical framework.

KU2US asked for help explaining his antenna's performance, and I think all the posters who said "It doesn't really work better than either antenna, except maybe in certain directions by luck" are on very solid footing.

I'm "mouthing off" now because every antenna thread on this site gets totally filled with nonsense as soon as the article is posted, and then those who come in and are even the least bit skeptical of the article's claims because of things they KNOW about antennas are treated like they're trying to suppress some important discovery in physics or are trying to personally insult and discourage the author.

- - - - - -

"In particular, N3OX, I believe I was referring to people like you in my statement about Mr. Fisher."

I'm confident that my contributions to eHam are on balance positive. I've made some technical assertions that I regret because I got emotional about some subject... mostly some jerk trying to sell $10 of wire to a newbie for $200 and claiming it's a miracle of modern physics.

I've had people convince me to rethink my position on some topics, like whether or not hams should even bother with *inefficient* antennas. KE3WD made me see how stupid the "FULL SIZE AND HIGH UP OR NOTHING" impulse is. I strive for transmitting efficiency in my own station but sometimes convenience is more important to people, and sometimes good enough is ... good enough.

But most of what I regret here is simply phrasing of what are otherwise technically sound ideas. I'm still learning, as should we all, but for you to suggest that I have nothing to contribute because I'm 28 years old is insulting and certainly not going to get me to stop "mouthing off"

I don't know everything about antennas but I've been building them for more than half of my 28 years.

I built my first antenna from scratch, a vertical dipole in PVC for my CB rig, when I was in 8th grade.

If you feel like having some fun at my expense why don't you go around the site dredging up all my comments on articles and in the forums that I've made that make you think ill of me and post them all in a list here.

It would actually be pretty helpful for me to know what I have to work on.

73,
Dan



























 
RE: Two HF Antennas One Feedline  
by N3JBH on September 12, 2007 Mail this to a friend!
Dan calm down your going have a stroke. Many folks say stuff on here that really is only meant to full fill there own personal prophecy or to instigate others.
Some times just remaining calm and really reading what they stated is enough to prove this. Case in point my favorite man of the ultimate wisdom W6TH Vitto.

Example from Vito “Jeff, evidently you did not understand what I had written, where as one must ignore the ignorant. Therefore I must break through traditional teachings to truth and the word of life.”

Yet he then writes this “Nothing new to me as I always boiled my water in the microwave, to purify and remove the salt.” Key word was always. He is some where around 85 years of age. Vito did you really Always do this?

He always claims to have tremendous secrets and techniques but there all top secret and can not be shared. Maybe what he really means is he wants us all too bow to his all mightiness with out proving his worthiness. Personally I think that is far closer to the truth.

Now Dan there is far more on here that probably fall In that same class as well I would rather think I myself probably fit in there some place. But there are a few great guys in here to mane some I would suggest your self WB2WIK , W8JI , N6AJR , KE3WD ,and K0BG to name a few.
These gentleman have earned there place and respect on here Dan.

The others well some are great some well are just entertainment. So sit back enjoy the reading and take a chill Jeff.
 
RE: Two HF Antennas One Feedline  
by W6TH on September 12, 2007 Mail this to a friend!
.

How did Dr Yagi come to the conclusion that a two element Yagi antenna spaced two tenths of a wavelength for the reflector and one tenth of a wavelength for the director summed up the radiation resistance was 40 ohms Z and the forward gain to be five dB.

Dr Uda wrote a comprehensive article, a written document of the antenna and I double checked his writings, found him to be one hundred percent correct.

There was at the time no front to back ratio mentioned and I did the follow up and found there was a fifteen dB front to back ratio with the above measurements.

Did this back in the year of 1940, this hooked me on antenna systems. Got rid of my random wire set up.

W6TH

.:
 
RE: Two HF Antennas One Feedline  
by K1CJS on September 12, 2007 Mail this to a friend!
Dan,

First, I never said Ken's antenna was new or earth shattering. I suggest you re-read the thread. I said: "If it works for you, use it! Good luck.....". It seems that that was the sentiment echoed by most responders--until someone came in and started the derision by saying somebody has now claimed to reinvent the antenna system.

Secondly, I used Einstein and his theory as an example of someone who thought "outside the box", who formulated another approach to why matter and energy act the way they do, and someone who was way ahead of his time. I didn't say any of those statements applied to Ken or to anybody else. All I said was what happened to physics because of Einstein COULD HAPPEN to antenna theory someday.

Third, What gives you the authority to say what can be put on this site? I quote:

"I NEVER want to hear another antenna experimenter say that they've discovered something new about electromagnetic theory until they've exhaustively studied the antenna they've built in a quantitative fashion and come completely to the end of their rope in simulation and experiment."

Gee, I had no idea YOU owned this site. And further:

"I'm "mouthing off" now because every antenna thread on this site gets totally filled with nonsense as soon as the article is posted, and then those who come in and are even the least bit skeptical of the article's claims because of things they KNOW about antennas are treated like they're trying to suppress some important discovery in physics or are trying to personally insult and discourage the author."

I repeat, the 'nonsense' started with somebody's coming onto the thread and sniping at the author of the piece. Then you and your buddies got into the act. Until then the thread was civil and orderly. After that, it went to blazes.

I believe somebody ought to step back and make due apologies, because before they started with their claims of someone reinventing antennas and antenna systems, this thread was orderly and calm.

After all, the thread was just some people saying 'glad your setup works' and offering suggestions as to why it did to Ken before the self rightous nay-sayers and know-it-alls took it over.

73, and I do mean it.


 
RE: Two HF Antennas One Feedline  
by K1CJS on September 12, 2007 Mail this to a friend!
"Dr Uda wrote a comprehensive article, a written document of the antenna and I double checked his writings, found him to be one hundred percent correct.

There was at the time no front to back ratio mentioned and I did the follow up and found there was a fifteen dB front to back ratio with the above measurements."

You double checked him? Gee, I had no idea you had a doctorate in RF theory or that you were a contemporary of Dr. Uda!

My sincere apologies, Dr. Vito! (TIC)
 
RE: Two HF Antennas One Feedline  
by W6TH on September 12, 2007 Mail this to a friend!
.
N3JBH Jeff

I read your bio today and love the last sentence; Blessed are they that hear the word of God, and keep it.

Amen.

.:
 
RE: Two HF Antennas One Feedline  
by N3JBH on September 12, 2007 Mail this to a friend!
Thank You Vito. Yes Those are very good words to live by.
 
RE: Two HF Antennas One Feedline  
by W6TH on September 12, 2007 Mail this to a friend!
.

Chris K1CJS,

You don't seem to have a good word for anyone, not only here, but other postings as well.

You are getting to be a mental case Chris, I now see your posting and just pass it by, as though you are a nobody.


You and Jeff are classified as the terror of eHAM.
.:
 
RE: Two HF Antennas One Feedline  
by W6TH on September 12, 2007 Mail this to a friend!
.

N3JBH
Thank You Vito. Yes Those are very good words to live by.

How about; Love Thy Neighbor?

.:
 
RE: Two HF Antennas One Feedline  
by N3OX on September 12, 2007 Mail this to a friend!
"After all, the thread was just some people saying 'glad your setup works' and offering suggestions as to why it did to Ken before the self rightous nay-sayers and know-it-alls took it over.
"

This is the way I re-read it:

First: Glad your setup works

Second: Some speculation

Third: How did you measure it? We think it is a surprising result. Did you do A/B tests? You might try that.

Some of those comments were prickly ones about how claiming an antenna works without backing it up with some numbers really doesn't tell anyone anything.

Fourth: You made your hammer on plate glass comment, which is what set ME off anyway.

All I'd said before that is " did you measure this thing using A/B/C tests and a step attenuator? It would be cool if you did, but even if you only think the antenna is working well for you that can still be a useful thing in the pileups"

So I don't think I have anything to apologize for. Which leaves me in the clear to speculate whether others have to apologize for being "peeved" and offering sarcasm... and I just don't know. Fighting technical misinformation on the internet makes some people view eHam's articles in a bitter light.

As far as these threads going off on a tangent with comments fighting comments, that's what happens in an open unmoderated forum.

It would be far better if we were self-moderated like Slashdot but that's a lot of time and money spent to improve the commenting system.

It'd be great if we could democratically moderate me down to -1 flamebait and make my comments disappear if we thought my posts had no valid content other than to incite argument in the comments.

Dan






 
RE: Two HF Antennas One Feedline  
by N3OX on September 12, 2007 Mail this to a friend!
"Then you and your buddies got into the act."

By the way, who are me and my buddies?

I'm trying to find the pattern to what you're worried about here...

Is it those of us who basically said "You say it works better but with no data there can be no understanding"?

 
RE: Two HF Antennas One Feedline  
by K1CJS on September 12, 2007 Mail this to a friend!
Well, Dan, If I'm the hammer on the plate glass window, someone put dynamite under the foundation to begin with. I'm not going to go through it again, I've got better things to do. 73.
 
RE: Two HF Antennas One Feedline  
by K3UD on September 12, 2007 Mail this to a friend!
Not that unusual.

I have four 1/2 slopers coming off my tower fed with one feed line.
This consists of 1/2 slopers for 160, 75, 40, and 30 meters. These are four quarter wavelength wires fed at the same point. It took a while to put everything in resonance on the bands they were cut for but the system works well. Of course the tower looks kind of like a large Maypole. The triband HF Yagi and VHF beams on top of the tower serves as top loading for the system. The only drawback is that the 1/2 sloper wires tend to change the resonance of the tribander somewhat, but not enough to cause serious problems.

73
George
K3UD
 
RE: Two HF Antennas One Feedline  
by N6AJR on September 12, 2007 Mail this to a friend!
Well thanks for putting me in the company of those other folks here on Eham, Jeff, I am honored to be thought of in the same group. I am just a feller who has had a little training in electronics thanks to Uncle Sam and the Air Force, and have a lot of friends I can learn from.

I agree that it takes a while to figure out "good enough" is good enough.

My main example of this is my car. I run a ft 857d in it with a ATAS 120 on the deck lid. Not the best set up I could possibly do for RF output, BUT>>

It fits in the garage with out having to get out and take off the antenna. As an old diabled dude, I just can't get in and out a half dozen "extra" times a day for my antenna, so for me it is "good enough".

I use a full sized DK-3 on the truck and it works better, but I don't put the truck in the garage. I can put what I want on pretty much anything, as I have a few extra bucks, and am not married, so I do as I choose.

I actually have 3 more DK-3's in the garage and an ATAS 100 there too. Spares in case I break one, and I got a deal on them to boot. I used to have a Knott BB3 screwdriver and I also have a manual tune screwdriver, and gave them both away. I did not like the setup, but the folks who got them enjoyed them.

So its an interesting thought to be thought of as actually knowing something, but mostly it is experiance and common sense, and learning from others.

Now if I could just learn how to spell :)
 
RE: Two HF Antennas One Feedline  
by N3JBH on September 12, 2007 Mail this to a friend!
Aw Vito i do love you. i just rag on you some is all. but down deep in my fractured heart i really do love you. heck Vito i dont hold hatered towards any one. and my dear freinds that know me will tell you i have a very strong love for them. and your one them i do love.
 
RE: Two HF Antennas One Feedline  
by N3JBH on September 12, 2007 Mail this to a friend!
And Tom N6AJR i am sure you can atetst to what i said to Vito. you have some first hand knoweldge of how i am. If Alls Hams had a elmer like you have been Tom this would be the best hobby ever. your insights and emails have been both a insperation and a blessing.

Allthough soon i will kick your butt on DX. just sit back and see :)
 
RE: Two HF Antennas One Feedline  
by N6AJR on September 12, 2007 Mail this to a friend!
now there is gratitude, ya tell em how to do it and they build a better system and whoop your butt.. good luck Jeff and the gang :)
 
RE: Two HF Antennas One Feedline  
by VA7EML on September 12, 2007 Mail this to a friend!
Wow! this thread is not what I expected to see from amateur operators. This guy had a simple, direct question and he got sledgehammered by some of you! some of the comments were a bit too harsh for my liking, some were in honest playful jest. It was the ones that slammed this guy that tick me off. I have been around radio for all my life but only recently wrote my test. I would think there would be less bashing, more help/analyzing and encouragement. No wonder some people get the wrong idea about HAMs. Do these people work the bands like this too? if so it is not a good thing for our hobby.

My Grandfather would be rolling in his grave if he saw this.

73 de Erin-VA7EML
 
RE: Two HF Antennas One Feedline  
by W8JI on September 12, 2007 Mail this to a friend!
Look guys, everyone should just chill out. There isn't any reason to get into a bunch of personal attacks over nothing.

Someone connected two antennas together and asked why it worked.

No one can really answer that question because:

1.) There wasn't anything written that actually indicated it really did work better. Only that it seemed to work better.

2.) There isn't any real reason at all it should work better other than through pure luck

Pointing that out and the reasons why it is true isn't hurting a thing. People only learn by hearing the truth. Telling a big fat lie or spewing techno-nonsense just to make someone feel great isn't really helpful in the long run to anyone.

Internet is a strange place. We just have to accept the fact people misunderstand each other on occasion or that people disagree and get over it.

Name calling and personal insults don't do anything constructive. Neither does witholding accurate information.

73 Tom


 
What The HELL?  
by KU2US on September 12, 2007 Mail this to a friend!
Holy CRAPSHOOT! What have I started here? A somewhat simple question, Some great answers, some supportive comments, some GARBAGE. LOOK..Here it is in a nutshell, some more info to fuel the flames. I NEEDED a solution for my incomming signals-thats called RECIEVING. My QTH is low and full of QRM. I figured if I could utilize two different antennas together,with different polarities, this would help, and it DID. OK, so 50 watts goes to one antenna, and 50 watts go to the other, but, In my book, 50 watts out is not so different to 100 watts out. The G5RV hears better but is noisier, the vertical hears less, but is quieter. Put the two together, and I got a signal stronger and more readable than on each antenna seperately. As far as transmitting is concerned, this week is the Route-66 special event. I have so far 15 out of the 17 W6 stations with this antenna set up. I even broke about 4 pile ups with other stations running +/- a gallon. & as you all know, the conditions suck.. Try to convince me this antenna set up is not working or cannot work because of some formula or model, and it just wont happen..IT WORKS..PERIOD.. I was just asking WHY? Ken-KU2US..
 
RE: What The HELL?  
by N6NKN on September 12, 2007 Mail this to a friend!
Congrats Ken,

Good for you !!!!

Rick N6NKN
 
RE: What The HELL?  
by N3OX on September 12, 2007 Mail this to a friend!
"Try to convince me this antenna set up is not working or cannot work because of some formula or model, and it just wont happen..IT WORKS..PERIOD.. I was just asking WHY?"

Ken, math, models and measurements are what we have to figure out why antennas work the way they do.

I doubt that you'd deny that a tower full of big beams would outperform your antenna.

I also doubt you'd deny that your antenna obviously works way better than a mobile screwdriver mounted on a ground rod.

There's a whole continuum of performance between those extremes, and the G5RV, the vertical, and the combination are probably all about equal on that continuum.

If you really want to understand why it works the way it does first you need to understand in some quantitative detail HOW it works.

W8JI has said it and I've said it and others have said it and it may piss someone off for some reason ... but if you can actually measure a real difference in gain or signal to noise in all the directions you wish to work among the G5RV, the vertical and the combination, you are indeed a very lucky man to have hit upon a great accident of random antenna phasing.

73,
Dan









 
RE: What The HELL?  
by N3OX on September 12, 2007 Mail this to a friend!
And Ken, it wasn't a simple question at all.

In fact, if everything is as you describe it and you're thoroughly convinced that the combo is superior, it's probably one of the hardest to answer antenna questions anyone has asked on here.

It's not *UNANSWERABLE* but we'd need a lot more information about your installation and local noise situation to figure it out.

Dan
 
RE: What The HELL?  
by KU2US on September 12, 2007 Mail this to a friend!
Dan-Thanks..There are many that gave very informative answers. I doubt very much if I stumbled on anything Einstein-ish here. Yes antenna math is an answer, but not many of us can understand quantum antenna theory-hihi..This may sound stupid, but it is like this: I threw up a dipole in a tree, planted a vertical in the ground, connected them together, and Bingo! I was dumbfounded with the positive results! I know what I hear, and I know what I am transmitting, and I know that the results are from those 2 simple antennas in my back yard..sounds to simple, thats why I posted. I know about dipole height, resonance, counterpoises, soil conditions, and coax length, and on and on. But this all just seems like the opposite is happening when it shouldn't? Thats the reason for WHY? The formulas and models will tell us that what is happening should or will not happen, but it IS! I thought someone may have done the same thing with close to the same results, so I could verify my lets say accidental results. Thanks, Ken
 
RE: What The HELL?  
by N3OX on September 12, 2007 Mail this to a friend!
"The formulas and models will tell us that what is happening should or will not happen, but it IS! "

Not exactly. The formulas and models always show an effect when you put two antennas together. There's so much noise up in here, and I made a lot of it, so let me post this again if you missed it:

http://n3ox.net/files/combining.JPG

The black circle is my vertical. The beam pattern is my Moxon. The green kidney bean is the half-power split between the two. All on 20m.

There happens to be a little tiny bit of that kidney bean that actually has more gain than either of the two antennas alone. If I was most interested in stations to the WNW, that little bit where the green is further out in radius than either the black or the blue would actually be better than the combination.

But, in all other directions even if the Moxon were a fixed antenna, either the vertical or the Moxon would have more gain.

That little slice, though, depends so heavily on the efficiency and impedance of the two antennas and the way they're fed that it's not really predictable without figuring out an ENORMOUS amount of detail.

I could throw together a G5RV and a vertical in a model noooo problem. If you sent me the measurements of the antennas with respect to each other, we could get the geometry right. I'd need to know the exact length and angle to the ground and antennas that all feedlines made.

I doubt it would help the situation just because I'd have to guess what the currents in your two antennas were.

If you went and got an oscilloscope and a current probe and measured the actual current in each leg of the G5RV, the common mode current on the G5RV feedline and the current on the vertical all without disturbing them, on all the bands you wanted to know about, then we wouldn't have to guess at the currents... but that's a very fiddly measurement to make.

Then we get into the effect of surrounding objects. Metal and lossy objects will play a key role. We have to figure out how to stick them in the model.

So that's what we'd have to do. It starts to add up to a lot of work and many, many opportunities to screw up the measurement or model and learn nothing at all, or even worse, come to a false conclusion based on the over-simplified or wrong model and "learn" something that's totally wrong...













 
RE: What The HELL?  
by K1CJS on September 13, 2007 Mail this to a friend!
Ken, As I said before--if it works for you, use it and good luck with it. You hit on a combination that gives you what you needed.

As to why? I don't know--but I don't know the specifics behind the individual parts of the computer I'm using now, just how the various parts interact to make the computer do what it does. But I can use it just as you can use your antenna setup. 73.
 
RE: What The HELL?  
by W8JI on September 13, 2007 Mail this to a friend!
Hi Ken,

This is eHam and Internet. We should try to NEVER confuse Internet with people's normal behavior. :-)

When you randomly mix two antennas the only thing that happens is you get a different pattern, different SWR, and different efficiency.


There is also an effect all humans share where we perceive a difference when there isn't one. This is why we have to be careful when we work on a car, work on a radio, or work on an antenna. For example there is a modification to radios where diodes are replaced with PIN diodes. If you measure the radio before and after the change there isn't a bit of difference. But if people take the radio apart, spend over $100 changing diodes, and put the radio together they swear the radio is quieter and significatly better.

Another prime example of this effect is HiFi tube audio guys. They SWEAR they can hear the difference between oxygen free copper leads and regular copper leads. They swear they can hear a "warm sound". But when you blindfold them they can't tell a difference, and most tests have shown the will pick a transistor amp over a tube amp!!

From this you can see there are really only two answers.

1.) You got very very lucky and the combination of antennas and feedline lengths happened to focus the signal in a desired direction and away from noise.

2.) You felt it changed for the better, even if it did not.

No one can tell you why it worked as well as you feel it did because other than an extreme amount of luck in several areas it would not work better.

It is also possible a bit of the Audio-phile or PIN diode effect is involved, since you are most likely a human. Don't ever discredit the fact how we perceive is what forms our perception of what is real.

This is why, based on the information you gave, no one can answer your question. With a proper careful experiment an answer could be given, but there wasn't one.

There isn't anything to feel bad or good about. This is just the way it is.

What your question did do is expose some common myths and misconceptions.

Some people think science hasn't fully understood antennas. That's a myth.

Some people think combining two antennas into one receiver or transmitter allows diversity. That's a myth. It can only, if it changes anything, increase fading.

Some people think two antennas will transmit independently when combined and fill in coverage. That's myth. It can only change the overall pattern and move the nulls to a new spot. The pattern change might be good, but make no mistake about it..... there will be NEW nulls created if old nulls are filled in.

73 Tom
 
RE: What The HELL?  
by W4PA on September 13, 2007 Mail this to a friend!
>>Another prime example of this effect is HiFi tube audio guys. They SWEAR they can hear the difference between oxygen free copper leads and regular copper leads. They swear they can hear a "warm sound". But when you blindfold them they can't tell a difference, and most tests have shown the will pick a transistor amp over a tube amp!!<<

You should see how this bad joke has played out in the musical equipment industry. DSP modeling processors to get any sound you want from a guitar amp, featuring a pair of 12AX7's as a preamp! These guys building this stuff must have a hard time keeping a straight face when designing it...

Scott
 
RE: What The HELL?  
by W4VR on September 13, 2007 Mail this to a friend!
Antenna diversity reception has long been promoted as a means of improving over-all signal reception and reducing fading or multipath. Originally used at MF and HF it is now more commonly used at microwave frequencies. Take a good look at your wireless router, if you have one, and note the two antennas. If you have your doubts that these two antennas are not for diversity reception, go to the Cisco website and find out for yourself how it works.
 
RE: What The HELL?  
by N3OX on September 13, 2007 Mail this to a friend!
"Take a good look at your wireless router, if you have one, and note the two antennas. If you have your doubts that these two antennas are not for diversity reception, go to the Cisco website and find out for yourself how it works."

I bet they've got a voter.

Dan
 
RE: What The HELL?  
by W8JI on September 13, 2007 Mail this to a friend!
We cannot directly combine two antennas to get diversity reception, and there is no such thing as single frequency diversity transmitting without a link back from the receiving end that selects the best transmitting antenna.

Anyone claiming they have diversity of any type that reduces fading with an antenna that combines signals directly at radio frequencies or without a voting system of some type either doesn't understand radio... or is fibbing.

73 Tom
 
Two HF Antennas One Feedline  
by LEER66 on September 13, 2007 Mail this to a friend!
Thanks Ken for going for the "lets give it a try" approach. I have an NI4L multi element dipole and a Hustler 5 vertical. I said to myself, "looks intersting, I'll give it a try". Modified a two position antenna switch to have both or either. I noticed that my TS-870 will now auto tune all freqs with both antennas selected but it won't with just one or the other. Talked easily from TX to CT on 20M today with 100W (split between antennas). Normally I can do this anyway but it certainly did not degrade things to the point of not making solid contact. I told him what I did based on your article and he said it sounded interesting and thought he would also try it. I switched between antennas while talking to him and he said he noted some small differences when selecting them individually and as a pair. Hey, it was fun to try and I'll work on the arrangement a bit more and put the MFJ-259 on there and see what I find.
Thanks again.
73s' Bob
KE5KDT
 
RE: Two HF Antennas One Feedline  
by KU2US on September 13, 2007 Mail this to a friend!
Hey BOB: Now THATS what I am talking about..Trying something new (or not so). Let me know how your experiment works out-OK? There are a lot of variables I cannot account for, but all I can go on is the end result. Here is some info someone wanted: G5RV is 102' long at a 90 degree apex inverted V-up approx 50 feet at the apex,5BTV is 26' high trapped 10m thru 80m, 3 resonant radials per band at 1/4 wavelength, ground mounted approx. 2' above ground. Coax is RG-8 Mini for all, 30 feet from each antenna to the coaxial "T", feedline from the "T" to shack is approx. 64 feet. Both antennas are separated from each other horizontally by +/-30 feet. Soil conditions are rocky, Nearest structure minimum is my house with a steel roof at aprox. 20 feet for the 5RV (tip of leg pointed east) and approx 95' for the vertical. Hopes this helps somewhat.. Ken
 
RE: Two HF Antennas One Feedline  
by W4VR on September 13, 2007 Mail this to a friend!
Of course you can't simply combine two antennas for diversity reception...even Wikipedia will tell you that much! For those of you who want to find out how such a system really works, there is abundant information on the web describing these systems. If you want detailed information there are several patents on diversity systems that you can download and get the real nitty gritty. These eham threads are too basic to go into any technical detail..a lot of people would skip and go somewhere else.
 
RE: Two HF Antennas One Feedline  
by W4LGH on September 14, 2007 Mail this to a friend!
W6TH said..."W4LGH Alan, You must remember that all of your boat anchors had a built in antenna that tuned from 25 Z to 600 Z impedance, this was called a tank circuit and was a pi network tuner. Could tune an antenna that was mis tuned."

Vito, I am very well aware of what a tank circuit is, and EVERY transmitter has one, not just old tube radios. 2nd this tank circuit could NOT tune a mis-tuned antenna, but would match the output of the radio to the complex impedances found on the coax created by the mis-tuned antenna. The antenna was STILL mis-tuned! I have beat my head against a wall on this subject so many times that I don't care how many tuners you have in your shack, how you tune them or whats actually taken place, but you are NOT tuning the antenna! The mis-match at the antenna remains the same, and the losses remain the same! Your radio might be happy, but your antenna is NOT. You can argue this point until you are BLUE in the face, but a fact is a fact. However if using an antenna tuner in your shack hooked to coax makes you happy, then so be it, use it, whatever!! A tuner in the shack is a work around, or band-aid, but if you are happy, then I am happy. All losses are turned to heat.

So at this point, I am going to agree to disagree and you do what you want. You won't find any antenna tuners in my shack, besides the one built into my FT-2000, which is NEVER turned on or used.

Have fun....whatever trips your trigger!

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

 
RE: Two HF Antennas One Feedline  
by N6AJR on September 14, 2007 Mail this to a friend!
As far as tuners go, tuner is really a misnomer, I do like match box better.

lets say you radio need a 10 to operate, and your antenna is a 7, the tuners adds 3 and the radio is happy. the antenna is still a 7 but the radio doesn't think so, so the tuner didi its job.

lets say the radio wants a 10 an the antenna is a 13. You will fiddle with the tuner till you get a - 3 and then the radio see a 10 and is happy once again. the tuner does not tune the antenna , it tunes the antenna system as presented to the radio.

a radio into an antenna that it likes will deliver more power than the radio going through a tuner, because the mismatch has to go somewhere, so it is lost as heat.

What this has to do with 2 different antennas on a single coax beats me. Ya'll have fun now, ya hear..:)
 
RE: Two HF Antennas One Feedline  
by KB3MMX on September 17, 2007 Mail this to a friend!
VERY COOL EXPERIMENT!!

If it works, "GOTA"!!! And enjoy!!

NEAT!!



--Chuck KB3MMX
 
Two HF Antennas One Feedline  
by W5VPU on September 22, 2007 Mail this to a friend!
It isn't very helpful to tell a guy his antenna won't work if he is talking to you on it.

Raymond
 
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