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How to Use Your Antenna Tuner

Do not contact (N4ZOU) on December 10, 2004
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How to use your antenna tuner.

There's more to it than what is in your manual or on most how to do it websites!

http://www.arrl.org/tis/info/Ant-tuner-op.html

Here is a neat site with a "T" network simulator. You can practice with this and figure out the proper way to tune one.

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

What more is required other than an SWR meter and properly setting the network components for matching the feed line to the antenna tuner? This article is really about how not to burn up your antenna tuner and keep the losses to a minimum. It's the little secrets that the manufacturer never wants you to know about and why that inductor, switch, or capacitor arced over or burned up. Here is a link to a site that provides some good information along the lines of this article.

http://www.raes.ab.ca/AntennaTips/AntennaTips.htm

The author of this article did not provide any means of checking the tuner and feed line system so it's missing important information that you need.

First of all a so-called antenna tuner in the modern since is really used as a feed line matching device. The only link between it and the antenna is that it shares the feed line with it. You're not tuning the antenna at all. Your just using it with your modern transceiver so you do not burn up that expensive set of output transistors (or tubes) and the output power will not be reduced due to a match that is not very close to 50 ohms.

Now, lets talk about commercially built antenna tuners. Open up the manual and look for the information that tells you what conditions it wont match. Are you there yet? Most likely you will never find that information! A modern "T" network with two capacitors and an inductor (or the AEA tuners with two inductors and a capacitor) will match a wide range of impedance ratios but they have their limits as all antenna tuners do. What is the limiting factor? The voltage and current rating of the capacitors, inductors and switches used. It's as simple as that. You really can't use the rating provided by the manufacturer on today's modern antenna tuners. Say the antenna tuner is rated at 300 watts. OK, 300 watts at what impedance and reactance? Nope, that's not in the manual! If you try and match very low impedance of say 15 ohms with that so called 300-watt antenna tuner with 100 watts the capacitors and switches will arc over from the several thousand volts developed across/through them. Even a so-called legal limit antenna tuner is going to develop problems in this situation.

So how do we deal with this problem? First of all we need to know what the impedance is at the end of the feed line. There are several ways to do this.

  1. Use an SWR analyzer.

  2. Use a noise bridge.

  3. Use an external SWR meter.

The analyzer is expensive if you don't have one already or can barrow one. Simply hook it to the end of the feed line where it would connect to the tuner, ladder line or coax. Coax requires no special attention or calculation, as it would connect directly to the output terminal of the antenna tuner. Ladder line feed will require some basic math if used with some type of Balun. Normally this would be the internal 4:1 Balun used in modern antenna tuners. Example: impedance reading is 200 ohms so dividing by 4 would provide a 50-ohm match. Another example: impedance reading is 25 ohms so the impedance on the other side of the internal Balun is going to be 6.25 ohms…this is going to be a problem! We will deal with this situation later in this article so lets continue. How do we know if the Balun really is 4:1? It might have been designed as a 4:1 Balun but the type of ferrite used could change the actual transformation along with other factors involved. It's better not to assume that the Balun is 4:1 and do the math just to find out it was not doing what you would think a 4:1 Balun should be doing! Simply connect the meter to the Balun. Setup the ladder line and tuner in the position where it is going to be used. Disconnect the bar or wire connecting the random wire post from the Balun connections and clip the meter to the Balun post where the bar or wire would connect to the random wire post and the other meter lead to the tuner ground post. Now you can read the impedance/reactance or SWR through the Balun.

0x01 graphic

Check this site for information on Balun design. http://www.qsl.net/iz7ath/web/02_brew/11_balun/pag01_eng.htm

0x01 graphic

The noise bridge requires you hook it up so you may hear the noise generated when using it. Simply hook the noise bridge to the Balun and transceiver, select the desired frequency, adjust the noise bridge and read the impedance and reactance.

If all you can manage to use is a SWR meter hook it up to the Balun and your transceiver this way.

0x01 graphic

This will require you to transmit so select a frequency that is not being used and only use a power level that will allow you to get a good reading with it. You can't tell if the impedance is high or low using an SWR meter but if the SWR is 3:1 or lower you can safely use your tuner if the impedance was on the low side of 50 ohms. If the impedance is off the scale or reads very high or very low on the Analyzer, Noise Bridge, or SWR meter you will need to change it so your antenna tuner can match it.

How do we change the impedance at the end of the feed line on coax or ladder line? By making the coax length longer or shorter! Wire Multi-band antennas used on the HF bands almost never have an impedance matching device between the antenna element and the feed line. Even antennas that do have them will not produce an exact match for the feed line across the entire band. This sets up a condition on the feed line where the impedance will be different across the length of the feed line. Generally, the impedance will repeat the element to feed line impedance every 1/2-wavelength times the feed line velocity factor. Changing the feed line length will change the impedance reading at the transceiver end of the feed line. A simple feed line matcher to allow inserting different lengths of feed line between the antenna tuner and the point where the feed line terminates in the shack at the mounting point on the strain relief or feed through. This setup works for ladder line and coax feed lines. Lengths used are 1, 2, 4, 8, and 16 feet long for coax or ladder line. If you operate on 160 meters you will need another length of 32 feet. One or more of these lengths will, in most instances, provide impedance your antenna tuner can live with. Generally speaking this will be between 50 and 600 ohms for a good antenna tuner. Anything above or below will cause substantial loss through the antenna tuner and problems will develop. The safe thing to do is find a feed line length where the SWR is 3:1 or better. Not only will the loss be less across the capacitors, switches, and inductors you will be able to use the internal automatic antenna tuner in your transceiver. Just remember that the feed line used will be carrying high voltages and current according to the match between the antenna element feed point and the feed line. Select the proper feed line for your line matcher and installation! When you start using your line matcher you will need to make a chart on how much feed line to use. While your meter is connected to the back of your tuner simply check different frequency's that you use on different bands and create a list of the require lengths to insert. You can make your line matcher as simple or fancy as you like. From just providing as easy way to connect different lengths between two connectors to a relay system with computer control! You could also find a length of feed line that will provide reasonable impedance on all bands. This is generally easy to do with resonant loop and dipole type antennas operated at odd multiple harmonics. I run a 160-meter loop sky wire and only insert a single 4-foot length of 450-ohm ladder line for the 12 and 17-meter bands. Here is an excellent site on building a line matcher and using it.

http://www.qsl.net/w5dxp/notuner.htm

Lets talk about that 25 to 6.25 ohm impedance transformation which would be found on an antenna like a short dipole or vertical antenna. 25 ohms would not be much of a problem but you don't want to bypass the internal 4:1 Balun by connecting the ladder line to the random wire post and antenna tuner ground. The RF flowing on the antenna tuner case can bite you and it upsets the balance of the ladder line feed system. What you need is an external 1:1 Balun. This is simple and cheap! Simply wind about 25 feet of coax around a plastic form about 6 or more inches in diameter to make an "Ugly Balun". Hook one end to your antenna tuner and the other end to the ladder line. Be sure to select the properly rated coax! You don't want it melting or arcing at the ends. Be safe and use RG-8 coax for it.

0x01 graphic

Did you buy a new or used antenna tuner and you find it works poorly or strange when used on ladder line? Do you want to check it and your balanced system just to make sure it really is balanced? This is easy and the equipment used is cheap and anyone can homebrew it!

Parts required:

  • 2 #47 bulbs rated 6.3 volts at 150 mA.

  • 2 bulb holders for use with the above bulbs.

  • 2 to 3 feet of ladder line.

  • 4 to 6 feet of hookup wire.

  • 4 alligator clips.

Cut your hookup wire into 4 even lengths. Connect 2 of the lengths of hookup wire to the bulb holders. Connect each end of the hookup wire with the bulb holder in the middle to each of the same side ends of the ladder line using 2 of the alligator clips. Make the exact same setup for the other side of the ladder line. It's very important to make them exactly the same. The 2 to 3 feet of ladder line forms a shunt for the bulbs on each side and both provide a balanced indicating system. The picture below should answer any questions on making up this simple and cheap test device.

0x01 graphic

Insert this line into your feed system and using low power tune to minimum SWR on the line at the antenna tuner. Slowly increase power so the bulbs will illuminate but not so much that they burn out! If both bulbs show equal brilliance then your feed line system and antenna is operating properly. If one bulb is dimmer than the other or does not illuminate at all then you have something wrong. As a double check reverse the leads on your balanced feed line indicator and make sure the other bulb is not simply burned out. It should illuminate with the same brilliance as the other bulb. If it checks ok then you have a problem with your Balun, feed line, or antenna. If the feed line and antenna elements check out ok, with no breaks, cold solder joints, or poor connections then you have a bad Balun which will need to be replaced. It could simply be a broken wire, shorted turns, or the ferrite has been overheated and/or cracked.

There is an antenna that is used in a balanced feed system that is not inherently balanced that would show imbalance with your feed line and Balun working just fine. This antenna is known as an End feed ZEPP. They will tell you that the antenna is ready to go "as is" but it's really not! To get the most efficient operation requires the use of the balanced feed line indicator when installing it. Install the ZEPP and the bulbs and clips from your balanced feed line indicator after striping just enough insulation to allow clipping the bulbs and alligator clips in the ladder line 2 to 3 feet from the antenna tuner Balun connections. Cut or lengthen the element as required to obtain a balanced condition on the feed line or change the ladder line length. Doing this will greatly improve the ZEPP antenna. Just remove the bulbs and alligator clips when you're done.

0x01 graphic

When checking a balanced antenna tuner like a Johnson Matchbox carefully look for bad switches, inductors, capacitors and other parts. Look at all the soldered joints and if they look bad, clean and re-solder as required. Here is an old 1K Johnson balanced antenna tuner that had no balance at all.

0x01 graphic

It looks like new but after removing several nuts holding down terminals with star washers it was found to have some ugly green tarnish in all the joints. After replacing all the nuts, terminals, and star washers and cleaning the studs proper operation was restored with very little or no imbalance anywhere on the 80 through 10 meters bands with a ladder line feed dipole. When you buy a used or homebrew antenna tuner never expect it to be 100% operational, even some new off the shelf units! Take it apart, inspect, and clean or replace all mechanical joints where screws and washers are used and make sure that all RF carrying Hardware is brass or copper, silver plating is a plus! If a magnet can pick up the hardware throw it away! You should do this with any new, used or homebrew antenna tuner you buy or build. As an example I once purchased an almost new antenna tuner from an upset buyer that had problems. After looking it over I found both capacitors had poorly aligned vanes that actually shorted out at near maximum capacitance! After fixing that problem and replacing all the steel hardware used with RF carrying parts with brass it turned out to be a nice little antenna tuner.

Speaking of checking out antenna tuners one thing to do is to check the loss through it. If you made the simple balance indicator you can use the two bulbs for an indication of loss through it, which will also show you if you have used the incorrect settings to provide a 1:1 SWR match. Cut two lengths of coax equal to the length of each of the bulb, holder, hookup wire, and alligator clips. RG-58 will work fine. Put the required coax connectors of your choice on each of the ends making sure to keep them identical. An inch or two behind each connector split the coax so you can connect a jumper to the center wire in the coax. It's very important to keep both coax lines identical.

0x01 graphic

Now connect one of the coax test lines with the bulb clipped to the slits in each end to the input connector and the other test line of coax with bulb to the output of the tuner and feed line to the antenna. Now the center wire in the coax is used as the shunt for the bulbs. Simply tune up as normal at low power so you don't burn out the bulbs and then increase the power so that the input bulb glows and note the bulb on the output of the tuner. It should glow at or just very slightly dimmer than the bulb on the input coax section. If there is a big difference then you have used incorrect settings for the tuner to provide a low SWR or you have problems in your antenna tuner. Again, double check and swap the coax sections to make sure you made them properly. If you get the same results then switch to a 50-ohm dummy load and reset the antenna tuner for a 1:1 match and recheck. At 50-ohms in and out of the tuner there should be almost no loss. Double-check your antenna tuner settings. If it's a new antenna tuner send it back! If it's used then you need to go through it and thoroughly check it for bad connections or burned up capacitors, switches, inductors, or connectors. You can calculate the loss through the tuner. Use the dummy load and apply just enough power to just get a small glow from the input bulb and then back the power down just enough that it goes out. Write down the power required to do this. Now apply just enough power that the output bulb just starts to glow and write the power level required. Now swap the input and output cables and recheck and average the numbers. Now using simple math you can calculate the loss across your antenna tuner. When using a dummy load and your loss ratio is low or none then you have a good antenna tuner. If you get a large ratio of loss through the tuner connected to your antenna and feed line system then you should check things out and fix the matching problems before you run the power up and consequently burn up your antenna tuner.

0x01 graphic

You can use this setup with your internal Balun. Just connect a short jumper from the end of the coax that would normally go to a coax feed antenna and connect it the same way as shown above with the SWR meter between the output of the antenna tuner and the input of the internal with the jumper from the random post disconnected. Now you can do a check and see if you have the proper inductor and capacitor settings with your balanced antenna system. Just remove both coax sections and hook the Balun back up normally and use the selector switch to select the random post for use with the Balun.

As you can see, it's not all that difficult to properly setup and use your antenna system if you have the required knowledge and simple tools to do it with. The problem comes with some manufacturer that does not want you to know how to check out your antenna tuner. I can't even guess at the number of them that have been built and sold using poor construction materials and practice in assembling them. If you burn it up they may claim it's your fault and in some cases they are correct but they did not supply you with all the required information and tools you needed, which would have also allowed you to see any and all problems with the quality of there product. Sort of a catch 22 situation from the old movie of that title!

Just a quick note to all about my recovery. My neurosurgeon gave me my driver's license back and sent my therapist (thera-pest) packing! I can now use power tools and I can get around pretty well but I still have bouts of confusion, weakness on my right side, and this strange problem with numbers. He can't tell me if this will ever go away. I am still alive and kicking anyway! Oh the pleasures of a drill press and jigsaw on a homebrew project! 73 all and happy operating. Scott N4ZOU.

Member Comments:
This article has expired. No more comments may be added.
 
How to Use Your Antenna Tuner  
by WD0CT on December 10, 2004 Mail this to a friend!
Thanks Scott! Simply a great article.

73, Steve
 
RE: How to Use Your Antenna Tuner  
by LNXAUTHOR on December 10, 2004 Mail this to a friend!
- excuse me if i'm wrong, but isn't bringing balanced line into the shack possibly introducing problems?
 
RE: How to Use Your Antenna Tuner  
by LNXAUTHOR on December 10, 2004 Mail this to a friend!
- btw, much of the prose in this article makes no sense to me...

- am i wrong?
 
How to Use Your Antenna Tuner  
by VK2GWK on December 11, 2004 Mail this to a friend!
It is a pity that the author is not able to explain things more clearly. The article is technically very good and has heaps of good suggestions. However the way things are explained is very woolly and will not be of much use to the new hams that would benefit most. Or is it just me that is poor reader....
 
RE: How to Use Your Antenna Tuner  
by KB7LYM on December 11, 2004 Mail this to a friend!
Its wooly alright! I could nit a sweater from it.
 
How to Use Your Antenna Tuner  
by WA6BFH on December 11, 2004 Mail this to a friend!
The phrases or explanations may seem "wooly" but, for the Ham that really wants to learn -- the concepts are plain!

All they need to do is pull down their Shrader, or Bill Orr handbooks down from the shelf (all REAL Ham's have a technical library right?) and they will get the point.

They will in fact really learn it better, if only for the sake of saying, "well, he could have stated that better,,, Hrrrrmmph"!
 
How to Use Your Antenna Tuner  
by AA3WS on December 11, 2004 Mail this to a friend!
I really like the graphics.
AA3WS
 
RE: How to Use Your Antenna Tuner  
by WI4CW on December 11, 2004 Mail this to a friend!
Good article. You can learn from just about all the articles.

Those of you that are critiquing the article - and have commented - you will of course provide a cut from the section that you are griping about - and your proposed changes to make it 'less wooly' - otherwise keep your yap shut.

To the author: Thank you for your time and contribution
 
How to Use Your Antenna Tuner  
by W4LGH on December 11, 2004 Mail this to a friend!
Great article! I have argued this with fellow hams for years, that a tuner @ the end of your feed line will NOT tune your antenna! It will only match the impedance of the feed line to your rig. Now if you put the tuner/matchbox @ the antenna, thats a different story, and it will then match the antenna impedance to the feedline. Still this doesn't mean your antenna is radiating properly.

Another MYTH is, I have a LOW SWR so I know my antenna is working ok...WRONG! You can put a 50ohm carbon resistor across your coax and have a 1 to 1 SWR, but your signal isn't going anywhere. SWR is a good "quick check" but NOT the end all of a proper working antenna.

Another one I like is...I have a 50watt radio & a 6db gain antenna, so I am putting out 200watts. Well, in a perfect world, it might be close to 200watts ERP, but a simple 3db loss in feedlines changes this, and no one ever seem to figure in the loss in the feed line. Also being that an antenna is a passive device, it can not have or produce any gain, it has 6db less loss, by focusing your radiated power in a given direction.

Its good to see hi-tech articles like this and would love to see more.

73 & Happy Holidays de W4LGH - Alan
http://www.w4lgh.com
 
How to Use Your Antenna Tuner  
by WD4HXG on December 11, 2004 Mail this to a friend!
QUOTING "LNXAUTHOR on December 10, 2004 - excuse me if i'm wrong, but isn't bringing balanced line into the shack possibly introducing problems?"

I brought 450 ohm line into my shack and it solved a number of problems. Foremost is the loss that was incurred in coax. I now have much less RF floating on unwanted surfaces around the shack and a 20 dB improvement in the radiated power.

SCOTT - Good article. Ignore the detractors. If there is a problem then they need to step up to the plate and write their own. 73
 
How to Use Your Antenna Tuner  
by WV4I on December 11, 2004 Mail this to a friend!
Thanks for a great article that obviously took a substantial amount of time to prepare. A copy goes into my ARRL Antenna Book for quick reference. This article is certainly a refreshing break from many of the articles, some of which accomplish nothing but to begin a long series of shallow, pointless rants.
 
RE: How to Use Your Antenna Tuner  
by KT0DD on December 11, 2004 Mail this to a friend!
For Lnxauthor:

That's the whole point of checking to see if your 450 line is truly balanced or not as illustrated in the article. I run 80 Ft of 450 Ohm line to my multi-band doublet right from the tuner in my shack, and I run up to 1KW+ with no problems. If you get a lot of RF back in the shack, you've got some antenna / feedline tuning to do. 73.
 
RE: How to Use Your Antenna Tuner  
by NE2I on December 11, 2004 Mail this to a friend!
When you balance your antenna using ladder line, all
of the radiation is removed from the feedline.
Using the method described in the article can help in
giving the antenna a good balance. There was a similar article on the net (look up rhombic homepage) that used
RF ammeters for measurement but light bulbs are cheaper!

Good article!

George NE2I
 
RE: How to Use Your Antenna Tuner  
by K0BG on December 11, 2004 Mail this to a friend!
Well, he's right about the specs on most tuners (couplers actually). While "T" designed tuners provide a lot of bang for the buck, they can be very lossy. The QST articles about the automated EZ tuner (reprinted in the latest handbooks) has some very good information about the potential losses.

To me, another interesting point is that a lot of new amateurs think they HAVE TO have a tuner for any antenna. The antecedent is, there is no substitute for a resonant antenna.

Alan, KØBG
www.k0bg.com
 
RE: How to Use Your Antenna Tuner  
by K4RAF on December 11, 2004 Mail this to a friend!
"excuse me if i'm wrong, but isn't bringing balanced line into the shack possibly introducing problems?"

No, balanced line is just that, balanced. No problems in 20 years @ 1500 watts. Just because it doesn't have a shield, doesn't mean it radiates.

To all of you who say "All I can put up is a G5RV for all bands", what you really need to do is cut that balun & coass out of the line & run twinlead right to the tuner.

If you are making an antenna yourself (gasp!), measure the total space between your supports, split it, center feed it with ladderline & you will do far better on all bands than any transformer antenna like a G5RV...
 
RE: How to Use Your Antenna Tuner  
by LNXAUTHOR on December 11, 2004 Mail this to a friend!
KT0DD:

- thanks for the concise explanation...

- btw, i hope that i didn't sound too harsh concerning the article (like others have mentioned the graphics are good)... it's just that it was hard to absorb some of the technical content... (i'm still learning)
 
RE: How to Use Your Antenna Tuner  
by W6TH on December 11, 2004 Mail this to a friend!


A great article and well written. Balance that line and get rid of the RFI and other interference. Remember that to balance the open wire line will mean the feedline will be equal amplitude and opposite in phase.

The efficiency of an antenna is determined by the ratio of its "radiation resistance" to its "loss resistance".

Thanks to you Scott.

.: W6TH
 
RE: How to Use Your Antenna Tuner  
by KB9YZL on December 11, 2004 Mail this to a friend!
Well,…………. First of all, I’d like to thank the author for the considerable effort that obviously went into the writing of this article. I make it a policy to be appreciative whenever someone goes out of their way to help me.

I will confess that some parts of the presentation left me a bit confused, but I can’t bring myself to be critical of the article because of my shortcomings. I never expected one, single, (and free) article to provide total enlightenment. (Hell,….. If technical points were easy, I’d know why this article is too wide for my screen setting, while the rest seem to fit!)

Like the marine compass that merely points North, this article has helped to show me the direction in which I need to “steer”, to attain my goals. Those details that are still unclear are now revealed as the next areas I need to concentrate my researches on!

Kent Carroll
KB9YZL
“Appliance Operator”

 
RE: How to Use Your Antenna Tuner  
by K3AN on December 11, 2004 Mail this to a friend!
The article was way to long. Any beginner who needs this kind of information is going to be lost long before he gets to the end.
 
What length is appropriate......  
by KA4KOE on December 11, 2004 Mail this to a friend!
It needs to be just a long is needed to get the job done. In this case, the subject matter is indeed appropo to the length of the discussion. Or do we simply have a few hams or detractors out there who are afflicted with attention deficit disorder and need to take their meds?

Hmmmmmmmmmm? HMMMMMMMMMMMMMMMM???

KA4KOE
Fellow Author
 
RE: How to Use Your Antenna Tuner  
by N6AJR on December 11, 2004 Mail this to a friend!
Krusty old Kurt Sterba will argue that you are tuning the antenna.. but let me ask, if a divice has 2 knobs and 1 switch, how hard can it be to use... or cheat and get an auto tuner for tose who can carry a tune in a bucket
 
RE: How to Use Your Antenna Tuner  
by K8JDC on December 11, 2004 Mail this to a friend!
Scott,

I appreciate all the work you put into writing this article. Thanks for the information and good luck with your health. Take care.

73

Dave / K8JDC
 
RE: How to Use Your Antenna Tuner  
by W6TH on December 11, 2004 Mail this to a friend!


Tal;king about lamps, bulbs, heater, etc:

1904 Sir John Ambrose Fleming worked to develop the first rectifier and in 1904, while working for the Marconi Company, he was faced with the problem of detecting weak wireless signals. He was inspired by his work with Edison’s lamps back in 1889 and decided to try inserting one of the lamps in an oscillatory circuit containing a galvanometer. He had found the solution to the problem of rectifying high frequency wireless circuits.

He didn't use a tuner.

.:
 
RE: How to Use Your Antenna Tuner  
by W6TH on December 11, 2004 Mail this to a friend!


1911 Young radio amateurs are building receivers with whatever parts are available. Although headphones can be purchased...many public telephone booths become inoperative.

Oh you hams.

.:
 
How to Use Your Antenna Tuner  
by N3DRK on December 11, 2004 Mail this to a friend!
Fantastic! The best article I have seen on eham. Thanks Scott. What's next!
 
RE: How to Use Your Antenna Tuner  
by KC8VWM on December 11, 2004 Mail this to a friend!
Great article Scott!

Similarly, I would like to write more articles on similar subjects right here on eham myself.

Unfortunatly, my previous articles listed on eham have only resulted in a rather unpleasant personal experience for myself in the past.

I can see you spent a great deal of research and time on the subject and you did a commendable job.

Those are probobly some of the best graphic diagrams I have seen in a while. They really beef up your material.

Happy Holidays Scott!

73

Charles - KC8VWM
 
RE: How to Use Your Antenna Tuner  
by W3TTT on December 11, 2004 Mail this to a friend!
"1904 Sir John Ambrose Fleming worked to develop the first rectifier ... didn't use a tuner."

Of course not. Let's put it this way - I live one kilometer from a 50,000 watt BC transmitter. All i need to pick up this station is a little wire, a rectifier, and a crystal earphone. I don't need to tune anything. Just rectify the RF to Audio. Conclusion: rectifying and tuning are two different concepts.

By the way, great article on Antenna tuners.
 
RE: How to Use Your Antenna Tuner  
by VE3RPF on December 11, 2004 Mail this to a friend!
For thoes who think Coax is superior to Twin lead or ladder line.

Actually bringing Coax into the shack can give you more problems than bringing ladder line into the shack. Coax is unbalanced meaning that equal currents do not flow on center conductor and braid. An unbalaced condition can carry noise and in the case of high power, can cause large electrical field build-up and thus radiation into the shack. Ladder line however is balanced and has equal currents moving where the magnetic fields produced on the lines cancel eachother out along the line and therefore cannot radiate.

I enjoyed reading the article and thank you for presenting it here.

Regards,
Robert VE3RPF
 
RE: How to Use Your Antenna Tuner  
by VE3RPF on December 11, 2004 Mail this to a friend!
For thoes who think Coax is superior to Twin lead or ladder line.

Actually bringing Coax into the shack can give you more problems than bringing ladder line into the shack. Coax is unbalanced meaning that equal currents do not flow on center conductor and braid. An unbalaced condition can carry noise and in the case of high power, can cause large electrical field build-up and thus radiation into the shack. Ladder line however is balanced and has equal currents moving where the magnetic fields produced on the lines cancel eachother out along the line and therefore cannot radiate.

So why use Coax?
1. No need to translate the impedance with a balun.
2. Convenience, easy to work with and connect using appropriate connectors.
3. Most installations you will not have much problem with RF in the shack as long as connections are electrically sound and the impedance differential is not so huge as to create very large standing waves.

I enjoyed reading the article and thank you for presenting it here.

Regards,
Robert VE3RPF
 
Fleming's Thermionic Valve  
by KA4KOE on December 12, 2004 Mail this to a friend!
The idea of Fleming using his thermionic valve for radio detection didn't become apparent to him immediately, and it basically sat around in his shop for quite a while.

See http://www.eham.net/articles/8873

PHILIP
 
How to Use Your Antenna Tuner  
by W8JI on December 12, 2004 Mail this to a friend!
Just a few comments and corrections.

"Say the antenna tuner is rated at 300 watts. OK, 300 watts at what impedance and reactance? Nope, that's not in the manual!"

Well, it is in SOME manuals.

"If you try and match very low impedance of say 15 ohms with that so called 300-watt antenna tuner with 100 watts the capacitors and switches will arc over from the several thousand volts developed across/through them. Even a so-called legal limit antenna tuner is going to develop problems in this situation. "

That a little bit of an exaggeration. The voltage and current largely depends on **reactance** of components used to match the load, the impedance, and the power level.

Using about 200pF and the full capacitance at at power of 100 watts, we have 1600V on 3.5 MHz and 224V on 28 MHz. Using half the capacitance will DOUBLE the capacitor voltage at the SAME load impedance and power level. Conversely using TWICE the capacitance will cut voltage in half.

Now here is what is interesting. Twice the capacitance, all other things equal, results in FOUR times the power rating so far as capacitor arcing is concerned. Pick a tuner with a LOT of capacitance and a heavy conductor in the inductor if you want a high power tuner.

In a conventional T network the less capacitance used, the higher the voltage and loss. That's why you should NEVER set capactors at mid-scale on lower bands. One or both capacitors should always be at full capacitance if possible.

The worse place for using tuners is with a LOW impedance on low frequencies, and you should ALWAYS tune for maximum capacitance. ALWAYS. Never start at half-capacitance as some people say.

"some type of Balun. Normally this would be the internal 4:1 Balun used in modern antenna tuners."

Tuners are wisely getting away from 4:1 baluns now and using 1:1 baluns.

"Simply connect the meter to the Balun. Setup the ladder line and tuner in the position where it is going to be used. Disconnect the bar or wire connecting the random wire post from the Balun connections and clip the meter to the Balun post where the bar or wire would connect to the random wire post and the other meter lead to the tuner ground post. Now you can read the impedance/reactance or SWR through the Balun."

Not really. In some tuners this works, in many tuners it does not. It really depnds on the type of balun and how the manufacturer wired the balun.

"This will require you to transmit so select a frequency that is not being used and only use a power level that will allow you to get a good reading with it. You can't tell if the impedance is high or low using an SWR meter but if the SWR is 3:1 or lower you can safely use your tuner if the impedance was on the low side of 50 ohms. If the impedance is off the scale or reads very high or very low on the Analyzer, Noise Bridge, or SWR meter you will need to change it so your antenna tuner can match it."

A few paragraphs up the author states a 15 ohm impedance is a problem that basically no tuner can handle. Now he says it is "good" for the impedance to be less than 50 ohms. Factually that is incorrect.

The idea just above, that if line SWR is over 3:1 the tuner will have a time matching it, is INCORRECT. Tuners as a general rule actually have a better time matching impedances HIGHER than 50 ohms by a good amount. For example a MFJ-989 on 160 meters has peak efficiency and power handling into a load of a few thousand ohms, which more than 30:1 SWR!

SWR tells us almost NOTHING about how the tuner network components behave. You have to know the network and the impedance.

" What you need is an external 1:1 Balun. This is simple and cheap! Simply wind about 25 feet of coax around a plastic form about 6 or more inches in diameter to make an "Ugly Balun". Hook one end to your antenna tuner and the other end to the ladder line."

That's almost no balun at all for 160 and 80 meters, and in many cases it can actually increase unbalance even on higher bands. It actually is much better to use a bifilar twisted pair of wires wound on a proper stack of ferrite cores. Air core baluns have their place in life, but in restricted applications of narrow or moderate bandwidth and known common-mode impedance situations. They are good at the feedpoint fo Yagi's, for example. They are generally inferior to core-type baluns when feeding multiband antennas.

"Insert this line into your feed system and using low power tune to minimum SWR on the line at the antenna tuner. Slowly increase power so the bulbs will illuminate but not so much that they burn out! If both bulbs show equal brilliance then your feed line system and antenna is operating properly. If one bulb is dimmer than the other or does not illuminate at all then you have something wrong. As a double check reverse the leads on your balanced feed line indicator and make sure the other bulb is not simply burned out. It should illuminate with the same brilliance as the other bulb. If it checks ok then you have a problem with your Balun, feed line, or antenna."

It's very important to understand that equal brillance does NOT mean the antenna is balanced, and things are OK. Equal currents DO NOT mean a line is balanced.

In order to know if the line is balanced, the detector HAS TO MEASURE OR INCLUDE PHASE.

". If you made the simple balance indicator you can use the two bulbs for an indication of loss through it, which will also show you if you have used the incorrect settings to provide a 1:1 SWR match. Cut two lengths of coax equal to the length of each of the bulb, holder, hookup wire, and alligator clips. RG-58 will work fine. Put the required coax connectors of your choice on each of the ends making sure to keep them identical. An inch or two behind each connector split the coax so you can connect a jumper to the center wire in the coax. It's very important to keep both coax lines identical."

The section on loss is exaggerated in importance and isn't really accurate thinking. If the tuner has noticable loss from a bad connection, it is a self-eliminating problem. At even a few dozen watts the connection will fail. All that power goes into heat, and the heat is all at the point of loss.

The loss is generally from operation at higher Q's, and most increased loss is caused by using too little capactance. The majority of loss is almost always in the inductor, and is almost always I squared R loss in the WIRE used to wind the inductor. It isn't in capacitors, contacts, or connections as a general rule. Even the contact resistance of roller inductors is largely negligable, most of the loss being in the coiled winding of roller inductors.

In conventional T networks we can minimize loss by using as much capacitance as possible to match the load.

Personally I wouldn't waste time trying to measure loss with light bulbs. It really isn't a very good system. If current was half, efficiency would be 25%! That would really suck, and a typical "3KW" tuner coil would melt down at a few hunderd watts of RF.

Even if we couldn't see a noticable decrease in brightness, the tuner may have power and HEATING limitations caused by loss. If you lose as little as 25 watts in a tuner, things can heat up. By the time you lose 100 watts the tuner is making as much heat as a 100 watts lightbulb inside one small area of the tuner! Something will melt.

73 Tom
 
RE: How to Use Your Antenna Tuner  
by W8JI on December 12, 2004 Mail this to a friend!
RE: How to Use Your Antenna Tuner Reply
by VE3RPF on December 11, 2004 Mail this to a friend!
For thoes who think Coax is superior to Twin lead or ladder line.

Actually bringing Coax into the shack can give you more problems than bringing ladder line into the shack. Coax is unbalanced meaning that equal currents do not flow on center conductor and braid. An unbalaced condition can carry noise and in the case of high power, can cause large electrical field build-up and thus radiation into the shack. Ladder line however is balanced and has equal currents moving where the magnetic fields produced on the lines cancel eachother out along the line and therefore cannot radiate. >>


Bullcrap!!!

Coax has EXACTLY equal and opposite currents on the shield and ceneter conductor when it is operating problem. It is PREFERRED line when radiation or ingress is a problem.

Ladder line is surrounded by external fields, and ALWAYS radiates to some extent even though the radiation can be very small at a distance.

73 Tom


 
RE: How to Use Your Antenna Tuner  
by W8JI on December 12, 2004 Mail this to a friend!
Let me correct what I wrote here. What it should say is:

Bullcrap!!!

Coax has EXACTLY equal and opposite currents on the shield and center conductor when it is operating properly. It is PREFERRED line when radiation or ingress is a problem.

Ladder line is surrounded by external fields, and ALWAYS radiates to some extent even though the radiation can be very small at a distance.

73 Tom

 
RE: How to Use Your Antenna Tuner  
by KI7YY on December 12, 2004 Mail this to a friend!
W8JI, You are wrong. Coax has three conductors; The center, The inside of the Braid (shield) and the outside of the shield. You will find that if you have an impedance mis-match at the feedpoint you will have rf all over the outside of the braid and hence all over your shack. True BALANCED feeders do not radiate.
As for your statement Bull****, remember the rejoinder " Cows do too, but they don't brag about it". It's all in your handbook....if the balanced feeders were radiating more than your coaxial cable they would have a higher loss.
It was an excellent article, Thank you for the effort.
73, Kirk, KI7YY
 
How to Use Your Antenna Tuner  
by WA1RNE on December 12, 2004 Mail this to a friend!

After several years of building and operating all sorts of HF antennas, I came to a couple of conclusions that could simplify things for many of us, with the exception of apartment dwellers or other folks with severe limitations on real estate or covenants:

Use a tuner for the 3-4 lower bands only; 160-30 meters;

Use a well designed link coupled balanced tuner. Regardless of what some say about them, they are not that complex to build. Right off the bat, it eliminates any need for lossy, poor designed baluns. The tuner I designed uses a technique from days of old, a movable link, allowing the amount of coupling to be adjusted. The inductor is an old Millen 1 KW rated tank circuit component for a transmitter that I purchased at a radio auction for about $5. I added some taps for band selection and antenna coupling.

Assemble the most important tool first - a decent technical library -including some good internet sites (eHam has several great links) and use it to create your own. Otherwise, purchase a used one like a Johnson Matchbox or another well designed commercial model. Do some research and check it out. Preview the manual, schematic, materials used and compare them to what your tech. library indicates is required for a good design.

For 20-10 meters, a tuner should not be required if you make some wise chices about the antenna type, its design and you follow some basic rules for installation.

....which takes you right back to your best tool, the techncial library. From many of the postings I see, it doesn't seem like many hams have a decent library - or if they do, they don't spend enough time reading and doing some basic research.

73, Chris
 
RE: How to Use Your Antenna Tuner  
by W6TH on December 12, 2004 Mail this to a friend!


As the two travelling waves pass each other in opposite directions, they set up an interference pattern called a "standing wave". At certain places on the feedline the voltages will add producing a voltage maximum, and at others their relative phase difference will cause a voltage minimum to exist on the feedline. These maximum and minimum points occur 1/4 wavelength apart. In the days when open-wire feedlines were used these points could easily be measured with simple indicators. Coax cable however presents another problem since the "inside" of the cable is not readily available for measurements. Consequently, VSWR measurements on coax are usually made at the transmitter end of the feedline. Therefore you are presented with the VSWR of the entire system which includes all losses associated with the entire system.

.:
 
RE: How to Use Your Antenna Tuner  
by W6TH on December 12, 2004 Mail this to a friend!


Here is another to read and think about.

There are a number of ways VSWR or its effects can be described and measured. Different terms such as reflection coefficient, return loss, reflected power, and transmitted power loss are but a few. They are not difficult concepts to understand, since in most instances the are different ways of saying the same thing. The proportion of incident (or forward) power which is reflected back toward the transmitter by a mismatched antenna is called reflected power and is determined by the reflection coefficient at the antenna. The reflection coefficient "p" is simply a measure of this mismatch seen at the antenna by the feedline and is equal to:

P =(Z1-Zo)/(Z1+Zo)

Here Z1 is the antenna impedance and Zo is the feedline impedance. Both Z1 and Zo are complex numbers so "p" is also a complex number.

Keep reading these posts people and you may wind up going for a electronic degree in engineering.

.: 73
 
How to Use Your Antenna Tuner  
by AI8H on December 12, 2004 Mail this to a friend!
Great article, Scott! Your articles are always an inspiration. The fun part comes when the vulture-like critic comes around to peck and police at boring length ~ which means that you are doing it right. Throw out some more bait!

Merry Christmas!
Jeff
 
RE: How to Use Your Antenna Tuner  
by W6TH on December 12, 2004 Mail this to a friend!


My last comment for the day and want to say what a wonderful post from Scott. took the words out of my mouth. Hope to be reading much more from you Scott.

My last comment:

Should you use coax for just one band, that is all it will work properly on and no others unless you want to heat the coax.

My comments are to agree with Scott and just brought out the theory behind his wonderful work of art.

Coax with a high standing wave is very lossy. The power being dissipated as heat in the feedline. This is not the case when using balanced feeders. 300, 450 and 600 ohm lines are practically lossless on the HF bands even when the VSWR is very high.

The end
.:
 
Learned discussions.....  
by KA4KOE on December 12, 2004 Mail this to a friend!
Its a sad state of affairs when the level of discourse descends to the level of the gutter...

We deserve better.
 
How to Use Your Antenna Tuner  
by KG4GSC on December 12, 2004 Mail this to a friend!
What an excellent article! As I have several homebrew "stealth" antennas at my QTH, as well as several "traveling" HF antennas, I do appreciate the matching unit hints and tips....esp. for my QRP antennas, as efficiency is so important. I've got a few antenna matching units I'm currently working on, so the article is timely...if nothing else, I will add to my knowledge base.

Scott, many thanks; your excellent work is MUCH appreciated. Glad to hear that your recovery is proceeding well, too.

Andrew
N4ABA
 
How to Use Your Antenna Tuner  
by N8BOA on December 12, 2004 Mail this to a friend!
I use mine to tune my antenna cause it is at the antenna

Sean
 
RE: How to Use Your Antenna Tuner  
by KB2RJH on December 12, 2004 Mail this to a friend!
Great Article even for the feeble minded like myself.
 
RE: How to Use Your Antenna Tuner  
by W8JI on December 13, 2004 Mail this to a friend!
I guess very few really read carefully before commenting.

VE3RPF waxed on about coax being unbalanced, and being"unbalanced" had NO CURRENT on the shield. There is no better way to describe such a silly statement except as BS.

My response to him was coax ALWAYS has the same current in the shield as in the center conductor when working properly in an unbalanced system.

Open wire, which VE3RPF claimed (read the reply)DOESN'T radiate as much as coax, was claimed to have no radiation or ingress. That isn't true, but when I pointed that out it led to another wrong statement from:

by KI7YY on December 12, 2004 W8JI, You are wrong. Coax has three conductors; The center, The inside of the Braid (shield) and the outside of the shield.
You will find that if you have an impedance mis-match at the feedpoint you will have rf all over the outside of the braid and hence all over your shack.>>>

Mismatch causes SWR. Lack of perfect unbalance in voltages at the source of load cause or exactly equal and opposite currents cause the coax to radiate, just like in any two wire transmission line. The SWR can be 20:1 and the line not radiate.

>>it". It's all in your handbook....if the balanced feeders were radiating more than your coaxial cable they would have a higher loss.>>

Radiation is almost always a very small part of loss in properly installed lines. Nealy all losses are in resistance of conductors at HF. All open wire lines radiate to some extent becuase fields always, even in a perfectly balanced condtion, extend outside the line. If you install it properly most radiation cancels some distance from the line, but near the line it ALWAYS will radiate with external fields.

That's why you shouldn't just lay open wire line anywhere, like on or in the soil or on a wet roof.

Please read the threads before jumping down my throat.

73 Tom
 
RE: How to Use Your Antenna Tuner  
by WB2WIK on December 13, 2004 Mail this to a friend!
Nice work, and excellent effort.

I didn't have time to read the saga that followed the article, but an article that creates a lot of discussion can't be bad.



 
RE: How to Use Your Antenna Tuner  
by K5MYJ on December 13, 2004 Mail this to a friend!
As usual on these forums, the responses to this article shows who the technicaly competent people are and who the MORONS (Appliance Operators) are.

I think it was a good article. Better than what is provided in the ARRL Handbook or the ARRL Antenna book.

But the term "ANTENNA TUNER" should be changed to "ANTENNA COUPLER". It was that way 40 years ago. The term "TRANSMATCH" is also a very approptiate term. These boxes match the transmitter to the load. They do nothing about correcting basic antenna problems.

Bob Macklin
K5MYJ/7
Seattle, Wa.

"REAL RADIOS GLOW IN THE DARK"
 
RE: How to Use Your Antenna Tuner  
by W5ESE on December 13, 2004 Mail this to a friend!
thanks, scott, for the nice article. i
appreciate your sharing your knowledge with
us.

i found this article to be helpful to me:

http://www.arrl.org/tis/info/pdf/9501046.pdf

i use 600 ohm open wire ladder line to feed my
HOHPL. i run it all the way into my shack. it
works well, and i use the antenna on
160-10 meters (on 160m fed as a marconi against
radials).

while it's no comparison to a big tower and yagi
or quad, i enjoy being able to use my rig on
all bands and not having to have a rotator.

73 all

scott w5ese
cw luddite
 
How to Use Your Antenna Tuner  
by AI8H on December 13, 2004 Mail this to a friend!
(Proven - I rest my comments.)
 
How to Use Your Antenna Tuner  
by KC0NYK on December 13, 2004 Mail this to a friend!
Scott,
First rate job. Anyone who can't understand your work might be better served to turn in thier ticket and start again.

What's 'wooly' anyhow?

Thanks for taking the time to put this together, now if my printer will behave, I think I will make a copy of this for my grandson who is getting ready to take his test.
 
How to Use Your Antenna Tuner  
by N4ZOU on December 14, 2004 Mail this to a friend!
Due to the large number of requests of printable versions of this article I have uploaded a PDF version of it to my Yahoo Geocities free Web page. The link is
http://www.geocities.com/n4zou/
I can't post a direct link to it due to restrictions from Yahoo :<{( .
If the link fails it's due to the limit Yahoo has imposed on the amount of data downloadable from each site so check back later and see if it's back up again.
I plan on updating my site but I am having a real problem with HTMP programming due to my disabilities but I am working on it. I cheated by replacing one file with another one on my site so if you have been to it before be sure and hit the reload button! The file name is tuner.pdf
 
RE: How to Use Your Antenna Tuner  
by VK1OD on December 14, 2004 Mail this to a friend!
Tom (W8JI), your comment " I guess very few really read carefully before commenting" is too true.

The original well intended article IMHO contains the full range from sound fact and good explanation to factual errors and misconceptions, and seems to ignore low cost instrumentation that most hams have or should have in favour of insensitive improvised setups (that we once needed).

The only safe way to comment is to write a complete replacement. By now, you must be wondering if bits of it could be corrected or clarified in isolation. You were never going to succeed in the eyes of those who liked the presentation and wanted to lap the content up, good and bad.

Peer level review prior to publishing would have added value to a well intended, but not-quite-there article. This is not a good peer level review forum.
 
RE: How to Use Your Antenna Tuner  
by VE3RPF on December 14, 2004 Mail this to a friend!
Tom W8JI

I normally would not reply to your post but for clarity sake here we go.
I did not say current does not flow in the braid. You need to read it again. The outer braid in coax acts as a shield confining RF energy within the line. The current that flows in the coax is mainly due to skin effect. The fields generated from the flow of current on the outer surface of center conductor and the inner surface of the braid ideally will cancel. Note I said ideally. A shift of 180 degee shift between the inner conductor and braid is required to get 100% cancellation. Since coax is basically an arrangement of inductance and capacitance and inductive and capacitive reactance are frequency dependant, it's impossible to reach the magic 180 degree phase shift at every frequency. Therefore not all the the field generated will be cancelled. This unbalance is usually not large and we normally do not worry too much about it. It can however produce some problems as far as generating heat when using lots of power and long runs and operating frequency.

Happy holidays,
Robert VE3RPF
 
RE: How to Use Your Antenna Tuner  
by W8JI on December 14, 2004 Mail this to a friend!
Reply
by VE3RPF on December 14, 2004

>>I did not say current does not flow in the braid.>>

What you said was coxial line being unbalanced does not have equal currents on the shield and center condutor. That is not true.

You also said balanced lines have less noise ingress than coaxial cables because they are balanced. That is not true.

The outer braid in coax acts as a shield confining RF energy within the line. The current that flows in the coax is mainly due to skin effect.>>>

That is not true either. The current that flows on the inside of the braid is a result of laws of time-varying fields. The current on the inside of the shield is ALWAYS exactly equal and opposite to the current on the center conductor. That is how any shield works, even the shield inside a transitter.

<<The fields generated from the flow of current on the outer surface of center conductor and the inner surface of the braid ideally will cancel. Note I said ideally. A shift of 180 degee shift between the inner conductor and braid is required to get 100% cancellation. Since coax is basically an arrangement of inductance and capacitance and inductive and capacitive reactance are frequency dependant, it's impossible to reach the magic 180 degree phase shift at every frequency.>>

There's no easy quick way to respond to that and be polite, except to say that isn't true either Robert.

Once the shield is several skin depths thick and if the ends are closed to a tiny fraction of a wavelength, the currents inside are ALWAYS equal and 180 out. That's just how shields work.

<<<Therefore not all the the field generated will be cancelled. This unbalance is usually not large and we normally do not worry too much about it. It can however produce some problems as far as generating heat when using lots of power and long runs and operating frequency. >>

Unbalance in currents does not cause heat Robert. Unbalance causes or allows radiation. I^2 R losses caused by current flow cause heat.

In order to radiate a measureable field or be subjected to ingress from external fields a cable with a shield more than several skin depths thick has to have common mode currents, and by basic rules the common mode on a coaxial line HAS TO flow over the outside of the shield. That is why strings of beads attenuate common mode currents without affecting internal currents.

No field of any substance passes through a shield that is more than several skin depths thick. It is possible, because of the weave, to have some conduction out of the center if a shield makes poor surface contact between conductors. Unfortunately the basic principles you describe are absolutely wrong.

The thing that makes Internet articles and replys good is everyone **can** learn something. The bad thing is people trying to learn have to be able to sort through the pure unvarnished BS that is always mixed with good information.

Peer-reviewed publications are a much more reliable place to learn. To learn about shields and coaxial lines the ARRL Handbooks are a good place for casual interest. EM Engineering texts are much better.

Internet forums, overall, should be taken with a grain of salt because well liked, well mannered, or well written prose isn't always technically correct and almost never is completely correct. Sometimes it is even VERY wrong, and looks very right.

I'm a little worried where we are heading long term when critical information comes more and more from popular or personal public opinion.

73 Tom
 
RE: How to Use Your Antenna Tuner  
by WA1RNE on December 15, 2004 Mail this to a friend!

Unfortunately, it seems that an increasing number of hams are relying exclusively on internet forums as their primary source of technical information.

It's been said before but I think it needs to be re-emphasized again: a personal technical library is a must, especially when it comes to understanding the basic concepts and theory around antennas and transmission lines. I'm sure many hams have accumulated some good references but it is very apparent that many have not - or have chosen to rely on someone else to teach them just what they need to know to get that weekend project done. Sometimes that's OK, but the next time you run into a technical problem with antennas, you will probably be starting from scratch because there wasn't much retained in the way of conceptual learning from the last project.

As a suggestion:

Basic transmission line theory and examples of their application are available in many amateur handbooks such as ARRL publications, Bill Orr's handbooks, the old standby "The Radio Handbook" etc., etc.

From there, if a concept is still not clear, go to the internet and research that specific topic or go to a university book store and purchase a technical reference.

73, Chris
 
How to Use Your Antenna Tuner  
by AI8H on December 15, 2004 Mail this to a friend!
'He' sure does go on.
 
RE: How to Use Your Antenna Tuner  
by W6TH on December 15, 2004 Mail this to a friend!


N4ZOU Scott. Needs to be corrected.

First of all a so-called antenna tuner in the modern since is really used as a feed line matching device. The only link between it and the antenna is that it shares the feed line with it. You're not tuning the antenna at all. Your just using it with your modern transceiver so you do not burn up that expensive set of output transistors (or tubes) and the output power will not be reduced due to a match that is not very close to 50 ohms.

This part is not true:

(and the output power will not be reduced due to a match that is not very close to 50 ohms).

Not true because look at a VSWR of 6:1. The amount of radiated power will be low compared to what is put into it. There will be reflected power that will not get into space.
A 2:1 ratio may get away with it but not if more.

.:
 
RE: How to Use Your Antenna Tuner  
by N0NWO on December 15, 2004 Mail this to a friend!
What's to know??? Just turn the knobs 'til the key doesn't bite you and the rig stops smoking.

MInton
 
RE: How to Use Your Antenna Tuner  
by VE3RPF on December 16, 2004 Mail this to a friend!
Tom W8JI

OK Tom you claim to know something but it's obvious you know little about the subject your talking about. My comments are backed by the 2005 Amateur Radio Handbook and other engineering books I have here.

Unbalanced line means the potential between the center and braid are at different potentials vs. Ground.

So Tom you're just arguing without knowing what the H*** you're talking about so quit while you're ahead.

Better yet, open a fricken book and learn something instead of inventing your own theories!

I happen to know what I'm talking about because I work in this industry.

Goods Day Sir!
 
RE: How to Use Your Antenna Tuner  
by KB9YZL on December 16, 2004 Mail this to a friend!
Geez...........Such vitriolic debate!

.....And you wonder why those of us "on the lower slopes" of the learning curve are sometimes a bit confused!

Kent Carroll
KB9YZL
"Appliance Operator"
 
How to Use Your Antenna Tuner  
by WA2JJH on December 16, 2004 Mail this to a friend!
nO MATTER WHAT ANYONE WRITES.....THANK YOU.

THANK YOU FOR YOUR TIME
TNX FOR SHARING WHAT HAS WORKED FOR YOU!
DO NOT LET THIS STOP YOU FROM FUTURE POSTINGS!
 
How to Use Your Antenna Tuner  
by WA2JJH on December 16, 2004 Mail this to a friend!
nO MATTER WHAT ANYONE WRITES.....THANK YOU.

THANK YOU FOR YOUR TIME
TNX FOR SHARING WHAT HAS WORKED FOR YOU!
DO NOT LET THIS STOP YOU FROM FUTURE POSTINGS!
 
How to Use Your Antenna Tuner  
by WA2JJH on December 16, 2004 Mail this to a friend!
nO MATTER WHAT ANYONE WRITES.....THANK YOU.

THANK YOU FOR YOUR TIME
TNX FOR SHARING WHAT HAS WORKED FOR YOU!
DO NOT LET THIS STOP YOU FROM FUTURE POSTINGS!
 
RE: How to Use Your Antenna Tuner  
by W5ESE on December 17, 2004 Mail this to a friend!
> It's been said before but I think it needs
> to be re-emphasized again: a personal technical
> library is a must, especially when it comes to
> understanding the basic concepts and theory
> around antennas and transmission lines.

while i agree that it's desireable to have some
good references, the arrl handbook and arrl
antenna book are now each ~$40. when i started
in the hobby (1975), the arrl handbook was $5.50,
and antenna book about $4. while i feel that
the new versions are worth every penny, that is
alot of pennies! i don't really fault new hams
that may find it challenging to acquire these
texts while trying to assemble a first station.

if you are an arrl member, there are many
articles on the web available to you for
free at:
http://www.arrl.org/tis/tismenu.html

some of these are available to both members
and non-members.

a classic article (4 stars) is 'Another Look
at Reflections' by M. Walter Maxwell at:
http://www.arrl.org/members-only/tis/info/pdf/Reflect.pdf

also, 'The Whys of Transmission Lines' by
George Grammer, also accessable at the arrl
tis pages.

there are also several articles on
transmission lines, tuners, and antennas at:
http://cebik.com/radio.html

73
scott w5ese
cw luddite
 
How to Use Your Antenna Tuner  
by N4XM on December 17, 2004 Mail this to a friend!
If you want to really learn about antenna tuners start with http://n4xm.myiglou.com.

Paul N4XM Inventor of the XMatch(tm) Antenna Tuner
 
How to Use Your Antenna Tuner  
by KB0YYO on December 19, 2004 Mail this to a friend!
Well done scott
It has been said by a poster here that beginers would be lost on your article. Well I am a beginer and I was lost before I read it and I know a lot more now than before I read it.
I will be more active in ham when I get more knowlege and feel comfortable getting my shack up and running. Your article was a big help for me and I thank you.
with out the graffics I may have been (lost) but with them it started to sink in. Will print and save.
Again Thanx
KB0YYO
Gordon
 
How to Use Your Antenna Tuner  
by AD5KL on December 20, 2004 Mail this to a friend!
Great useful article - thanks for all the effort...
 
How to Use Your Antenna Tuner  
by W3ULS on January 4, 2005 Mail this to a friend!
Thanks, Scott, for a very informative article.

I would add that the Ten-Tec 238A "High Power" Tuner uses a modified "L" circuit that avoids some of the pitfalls of the "T" circuit.

Also, the manual Ten-Tec provides for the 238A is excellent and covers some (not all) of the same ground that Scott's article did.

When I use my OMNI VI and the Carolina Windom 80 I find I do not need a tuner on the HF bands--at least in the CW segments. That makes life easy.

73,
John, W3ULS
 
How to Use Your Antenna Tuner  
by VE7ALQ on January 20, 2005 Mail this to a friend!
I have an Icom IC-706mkiiG transceiver and an Icom AT-180 fully automatic antenna tuner. I don't have to do anything to the tuner to get a good match to my antenna. In fact, the tuner has no external knobs or switches. When I QSY on CW, the AT-180 tuner automatically "tracks" the Icom IC-706 using the frequency available in the "Accessory" cable to look at (memorized) tuner settings. If the AT-180 tuner encounters a non-memorized frequency, it will take a whopping TWO SECONDS to match this frequency, and will squirrel the settings away in memory for future reference.
 
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