who here uses an ANTENNA TUNER?

[trx680]

Who uses an antenna tuner for their base CB?

I see there are manual and automatic tuners.

They worth having?

[MDYoungblood]

I use one for my ham antennas because they are all not trimmed to a specific resonant frequency. As for my CB antenna, it is so a tuner is not necessary.

3's

Greg

[443 Arizona]

i have an old old tuner, a "tenna tuner" has a Globe Electronics name on the meter.
i had used it before but always worked at getting a better match so as to eliminate it from the line and put as much juice thru to the antenna as possible.
on the meter is says to "tune for max." this thing has got to be from the 60's if not earlier.

[Blue Ox2]

I have a tuner inline with my 2M ham rig and I don't really know why.

I don't use a tuner on my CB Base antennas, just the SWR meter.

JMHO, 73,

Mike

[Bluerunner]

I use a little cheap radio shack antenna tuner on the input to my amp. Many amps don't have a input tuner and can present a high SWR to the radio when keyed up. Often the radio SWR meter shows a higher SWR into the amp than the inline SWR meter after the amp. Many presume that the radio SWR meter is just inaccurate because it doesn't agree, often it is not and is actually warning of a high input SWR of the amp. Correcting or improving the amp input SWR can result in improved radio performance better modulation and reduce harmonics.

[Gunner357]

I just got a MFJ-949E I really like it

[429smiley]

I use an antenna tuner because my metal antenna swr's will change slightly if it rains and I can tune to make the finals happy. 1.5 to 1 to flat. I probably waste more power than it is worth.

[Gunner357]

I have a manual MFJ949E I use for CB and Ham...... On the FT920 just to get it down below 3:1 and the Radio takes it over

[warlock35po]

Hello ,Once again there is no such thing as a so called "antenna tuner." A more accurate description wold be a xcvr matching device that will fool your radio into believing it is loading into a resonant load.If you have an actual S.W.R. of 2 or less don't waste your money unless you are happy seeing what you would like to see on your meters.On A.M. it takes a 4 times power increase to get you 1 S unit more on the other end.Expensive S unit.But to each his own.Regards,warlock35po

[The DB]

I disagree with warlock35po, and am happy to post video evidence showing that an antenna tuner does in fact tune the antenna, again.

Anyone who is interested in why this is the case should read up on something called the conjugate match. The reflections series of books by M. Walter Maxwell is a good start, or perhaps the freely available pdf called "Another Look at Reflections" which is an older version of the first seven chapters of said books. M. Walter Maxwell is an engineer who wrote these books and pdf for those who aren't engineers. And if the little math is to difficult, you can skip it. You don't need to understand the math to understand the concepts he talks about.

That being said, I wouldn't use an antenna tuner for single band operation such as CB. A single band antenna designed and tuned for CB use is optimal for the CB band and the areas near it. If you can't get such an antenna to tune, or to hold a tune, I would find out why, there is always a reason.


The DB

[radiogoon]

Embrace "The Toona". When you feed a multiband dipole with ladder line to the tuner you can ragchew putting a KW into it. It also helps when building antennas of home brew design. Like the apartments gutter system.

[warlock35po]

Hello,The D B. I respect your Opinion.I will not waste time posting further on this issue.I wish you and your family a Happy/Safe Covid 19 free Christmas and Holiday season.Regards,warlock35po.

[TNT1450]

I use an antenna tuner on my multiband dipoles connected to my ham rig, since the dipoles are resonant usually at the middle of each band but toward the ends the VSWR raises a bit. But I can tune the 10m element of one of my dipoles to 11 if needed.

If I had a dedicated CB setup I wouldn't bother with an antenna tuner. I don't with any other single band radio/antenna setup, like 2 meters for example. The tuning range is narrow enough the antenna should cover it all An antenna tuner on an antenna system which doesn't need it it just going to waste power. The smart thing to do is to make sure your antenna is resonant where it needs to be, then hook the radio directly to it. Of course, with an HF ham setup where you're transmitting over a very wide range of frequencies and therefore different antenna resonances, a tuner is needed.

[radiogoon]

Of course, with an HF ham setup where you're transmitting over a very wide range of frequencies and therefore different antenna resonances, a tuner is needed.

Exactly. I run a tuner on my 75 meter dipole because I feed it with 450 ohm ladder line to make it multi-band. No place I can't get it to load. However my stand alone 6m dipole is run without a tuner as it has been cut to the middle of the phone band.

73 OM

[Crowbait]

Its been many years since I CB'd and such, but if I had an antenna connected with any radio (no matter 2,6 10,11 ... meters) ... if I had a good transmitter-to- antenna match I wouldn't leave my tuner in line.
But, many antennas that I experimented with ... it was pretty much a "have to" for a tuner, cause mis-match would be all over the place with some of the crazy stuff I transmitted on ...lol
So, I think it is pretty much a personal preference and what sorta transmitter-to- antenna match you got. I don't think leaving it inline is an issue , even if you have a good match (if you wanted to) ... cause it shouldn't be making any difference if the need for it is "Nil" ....
Of course this is just my opinion and I'm no proclaimed Radio Engineer...
Just my 2 cents ....

[MN785]

Hello ,Once again there is no such thing as a so called "antenna tuner." A more accurate description wold be a xcvr matching device that will fool your radio into believing it is loading into a resonant load.If you have an actual S.W.R. of 2 or less don't waste your money unless you are happy seeing what you would like to see on your meters.On A.M. it takes a 4 times power increase to get you 1 S unit more on the other end.Expensive S unit.But to each his own.Regards,warlock35po

It really is unfortunate how many people get on youtube and become an instant expert and argue with physical experimentation... You are spot on warlock, it does nothing to the antenna itself, it does not resonate it. The people that say it "resonantes" an antenna have read only the most basic literature ~ just enough to have a believable idea of what is going on. DB clearly understands what a conjugate match is, and that's a big step not many CB'ers take, but I think he is stuck in the notion of infinitely small lumped elements and sees the entire setup as one single thing electrically, which it is not. An antenna not providing a match to the coax will create a reflection. A tuner does not change that, it merely creates another reflection at the tuner that sends the first reflection back to the antenna. This happens over and over until the antenna (or coax loss) absorbs the power. I am not trying to start a **Censored** contest because this argument has happened plenty times elsewhere on the internet and there is little need to go over it all again, I am merely posting this so people know it is not as simple as "it resonates the antenna" as that statement is wildly false. A few years ago, I would have agreed with DB, and often made his argument, but after being told I was wrong enough times, I tee'd in my oscilloscope between my tuner and antenna and literally watched these reflections happen with a modulated test signal. Just because the SWR is 1:1 and the tuner provides a 50Ω load to the radio, that does not mean the antenna is resonant - if it were, the reflections I saw would not be there as 100% of the signal that makes it to the antenna would have been absorbed with no reflection. Apologies for the rant, not trying to ruffle feathers. All that being said, tuners are an AWESOMELY invaluable tool!

[The DB]

You are spot on warlock, it does nothing to the antenna itself, it does not resonate it.

Actually it does. Most people in the hobby space have a very limited idea of what resonance is. They limit themselves to X = 0, which is resonance, but is actually a special case that some call self resonance, or an antenna that is electrically resonant with itself. The actual definition of resonance is equal magnitude, opposite sign. For example, if you have an antenna with an X of 200, and you feed it in such a way that the feed line, matching circuit, or whatever, has an X of -200, then the antenna is, by definition, resonant. The self resonant antenna I mentioned above fits in here as its magnitude is 0, and the opposite of 0 is actually 0. The principles behind equal magnitude opposite sign is how virtually every matching circuit works, be it L-networks, the ring on the Maco, v58 and v5000, the gamma on the Vector 4000 or the many yagi antenna's that use one, to literally almost everything else (although there are some rare exceptions).

The people that say it "resonantes" an antenna have read only the most basic literature ~ just enough to have a believable idea of what is going on.

On one hand, I get what you are saying, to a point. A lot of people start with 'its an antenna tuner so it tunes the antenna'. This group is definitely where you think they are knowledge wise. But not everyone in the hobby space that is saying that an antenna tuner tunes the antenna is in this group. Me for example.

Have you bothered to ask an electrical engineer this question? I have, several electrical engineers in fact. They all agree that an antenna tuner tunes an antenna. This is the most knowledgeable group of people that work with antenna's out there.

When it comes to books, well, I did mention the Reflections series and the freely available .pdf above, both of which were written by M. Walter Maxwell, an electrical engineer that worked for NASA and designed several antenna for various satellites. I would call his books and documents the basics of the basics when it comes to antenna knowledge, although I highly doubt most in the hobby would agree with them being being considered 'basic'. For anyone who wants to actually understand what is going on with antenna's his books and document make an excellent starting point. I can go on from here if you would like as my collection of books goes far beyond this level.

DB clearly understands what a conjugate match is, and that's a big step not many CB'ers take, but I think he is stuck in the notion of infinitely small lumped elements and sees the entire setup as one single thing electrically, which it is not.

Yes I do understand what a conjugate match is. Its part of what I consider the basics of the basics I mentioned earlier. I would also tell you that I have no problem breaking down what is happening with each component part, or looking at what is happening as a whole. There are things to learn from both points of view.

An antenna not providing a match to the coax will create a reflection. A tuner does not change that, it merely creates another reflection at the tuner that sends the first reflection back to the antenna. This happens over and over until the antenna (or coax loss) absorbs the power.

On this, as far as what is happening with reflections, we agree. More on this later as it comes up again.

A few years ago, I would have agreed with DB, and often made his argument, but after being told I was wrong enough times, I tee'd in my oscilloscope between my tuner and antenna and literally watched these reflections happen with a modulated test signal.

Really, the old "I used to think like you but" line? When people read things like this they often take it as a slap in the face. However, in this case I see this as actually humorous, not because it was used against me, but was used against someone who actually once believed as you did, and strangely got to the point you did in a very similar manner, then over time evolved to where I am now as I gained even more knowledge.

And while what I said is true, it doesn't feel good to have someone use this tactic against you does it. People really don't like to feel disrespected like this, and its not helpful to any conversation. Further it contributes to what you said that shows on my screen as "**Censored**". Even if your right about something, this is never the way.

Just because the SWR is 1:1 and the tuner provides a 50Ω load to the radio, that does not mean the antenna is resonant - if it were, the reflections I saw would not be there as 100% of the signal that makes it to the antenna would have been absorbed with no reflection.

A situation for you.

Take a half wavelength wire and feed one end to an antenna analyser, and tune its length to an electrical 1/2 wavelength. Be sure to ensure that X = 0. Now look at the SWR reading. If the wire is up in the air away from obstructions it will have an SWR of about 40 give or take. There you go, a resonant antenna with a high SWR. The thing to take away here is resonance does not imply an SWR match, and a high SWR does not mean an antenna is not resonant. While there is a relationship between the two it is a fallacy to use them interchangeably.

Now a question. Why do you assume (to the point of stating it as a fact, twice) that if the antenna was tuned by the antenna tuner that the SWR on the feed line between the antenna tuner and antenna would be a perfect match? This is incorrect and I don't know of anything in theory or practice that supports this idea in any way. The settings on an antenna tuner does not, and in fact can not change the SWR as measured on the wire between the antenna tuner and the antenna. Further, this has absolutely nothing to do with weather or not an antenna tuner actually tunes the antenna. From my point of view it is nothing more than a distraction from what we should actually be looking at.

Apologies for the rant, not trying to ruffle feathers. All that being said, tuners are an AWESOMELY invaluable tool!

I would agree with you here on both counts. I can type and I went far longer than I originally intended. What can I say, I love discussions about all things antennas, it doesn't really matter what aspect of antennas we are talking about. I did go back and shorten parts of what I said, so if anything sounds off I might have cut out something that needed to stay. Just let me know and I will put the full though in, or not if you don't want me to.


The DB

[MN785]

DB, I just got home. I would have replied sooner had I been here. You are right, I came off very disrespectful. I apologize for that and my choice of wording. Your statement regarding the tuner "tuning the antenna" is what threw me off as it isn't just the antenna being tuned, it is the antenna and coax as a whole circuit, and without that clarification, people usually assume the reflections in that piece of coax are gone ~ which they are not. Your last post clarified that and I agree with everything you said.

[The DB]

DB, I just got home. I would have replied sooner had I been here. You are right, I came off very disrespectful. I apologize for that and my choice of wording.

Accepted. I didn't think then that you meant it that way in the first place, or I would have reacted very differently.

Your statement regarding the tuner "tuning the antenna" is what threw me off as it isn't just the antenna being tuned, it is the antenna and coax as a whole circuit, and without that clarification, people usually assume the reflections in that piece of coax are gone ~ which they are not. Your last post clarified that and I agree with everything you said.

We agree on this, but I would take this one step further. When you look at the three parts of this system, the antenna tuner and the feed line are both impedance transformers. If you combine these two, then both act together to tune the antenna itself. For this to happen, SWR has to be present on the feed line because it is a by-product of the impedance transformation occurring on said feed line. This is why I was wondering why the SWR on that feed line still existing is taken to mean that the antenna is not also being tuned?

All this being said, at a fundamental level, the antenna itself is really nothing more than an impedance matching circuit as well, it matches the RF signal being fed to it to the impedance electromagnetic fields need to travel through space, so in the end, the whole setup is nothing but one big impedance transformer...


The DB

[warlock35po]

Hello,Very best I appreciate you taking the time to contact me.I havent been on much or would have replied sooner.Best regards in 2022 to you and your family, stay safe,Don warlock 35po ,VEI-CSP