I don't approach antenna tuning as an either/or, I'm always looking for a happy medium. If I can't find a happy medium I tune for resonance, then deal with matching or reducing feed line loss as a separate problem.
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RigExpert AA-650ZOOM Antenna Readings
- Thread starter NightThumper
- Start date
When you are measuring antennas through a length of coax the resonance you see on the analyser is very likely not the resonant frequency of the antenna as most think it is,
only under very specific conditions is the resonant point at the rig end the same frequency as the self resonace of the antenna.
Walt maxwells reflections tells us
"Any reactance added to an already resonant (resistive) load of any value for the purpose of com-pensation to reduce the reflection on the line feeding the load will, instead, only increase or worsen the reflection. It is for this reason, although contrary to the teaching of several writers, that the lowest feed-line SWR occurs at the self-resonant frequency of the radiating element it feeds, completely independ-ent of feed-line length. Any measurements that con-tradict this indicate that either the measuring equip-ment or the technique (or both) are in error"
only under very specific conditions is the resonant point at the rig end the same frequency as the self resonace of the antenna.
Walt maxwells reflections tells us
"Any reactance added to an already resonant (resistive) load of any value for the purpose of com-pensation to reduce the reflection on the line feeding the load will, instead, only increase or worsen the reflection. It is for this reason, although contrary to the teaching of several writers, that the lowest feed-line SWR occurs at the self-resonant frequency of the radiating element it feeds, completely independ-ent of feed-line length. Any measurements that con-tradict this indicate that either the measuring equip-ment or the technique (or both) are in error"
Sad to say, but you are wrong. Simple example. My antenna on desired frequency is in resonance, but 160Ohm
Mike
Mike, why don't you explain what you operate here and tell us how your working at resonant frequency with 160 ohms mismatch. This is just petty confusion and does not clarify anything.
This is exactly how ham operators use to create hate and discontent on our CB radios back in the days. It also explains why I never wanted to become a ham operator.
I had a radio mentor back in the days that was a ham, an asshole, and acted just like I've described above. Everywhere we went...he got into arguments...and it wasn't fun, but I wanted to learn something, so I put up with this SOB.
Some of my CB buddies were hams, but they preferred to work CB. I figured they probably felt insecure on the ham bands for whatever reasons. They tolerated most of the guys in our little group, but let somebody new pop-in to say hello...and they were on him like stink on...xxxx.
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338, your response here is a bit more informative, so why don't you explain the details for what you just described. and just maybe someone will learn something NEW on this forum: ": a public meeting place for open discussion, The club provides a forum for people with some common interest and collegial relationships."
I don't spend a lot of time explaining antenna theory in great detail for no reason. If my post wasn't enough to stir a thought, or a desire to research or even a question, that person probably doesn't really want to learn anything. It's just giving a man a fish at that point.
Oh, and there is the fact that I am still attempting to have a rudimentary misunderstanding of antenna confusion.
You just don't get it...if you don't think this thread has not turned into some confusion rather that trying to be informative. You guys weren't just scolding NightThumper.
Pride is the teacher, saying "I don't have to explain."
338, here is what you were talking about less than a year ago. I didn't have to look very hard.
I give you credit for learning whatever it is informing you now.
That is why I asked you to further explain...but now you can't be bothered. OK?
stryker antennas
I give you credit for learning whatever it is informing you now.
That is why I asked you to further explain...but now you can't be bothered. OK?
stryker antennas
So 338 once you tune for resonance at the antenna feed point how are you dealing with a high SWR? 1) Shut coil, 2) Balun, 3) transformer, 4) adjusting the length of your coax, 5) Antenna tuner, 6) shorting stub? All of the above or something else.
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I believe Night Thumper made a great point. It depends on your equipment. Neither way is wrong.
Makes no sense to tune for resonance if your equipment isnt going to tolerate an swr between 1.5-1 and 2-1. Dei transistors are swr sensitive so its only logical to tune for swr at least below 1.3-1 just like with the HG's. If your equipment is happy with 1.5 to 2 swr range tune for the happy medium or resonance.
I see no one right way.
Makes no sense to tune for resonance if your equipment isnt going to tolerate an swr between 1.5-1 and 2-1. Dei transistors are swr sensitive so its only logical to tune for swr at least below 1.3-1 just like with the HG's. If your equipment is happy with 1.5 to 2 swr range tune for the happy medium or resonance.
I see no one right way.
I can't help all that often, but I try when I can. He admitted he made false statements. He posted expecting "fireworks". He said he knew he was wrong, yet didn't care.338, here is what you were talking about less than a year ago. I didn't have to look very hard.
I give you credit for learning whatever it is informing you now.
That is why I asked you to further explain...but now you can't be bothered. OK?
stryker antennas
Does this sound like someone that wants to learn anything new? Nope.
Just in case he actually did, I threw out a hook in case he really did want to learn. If he doesn't bite, I'm not going to preach to deaf ears.
Wow...just wow. I’d prefer to learn from someone else if you don’t mind. Hence the reason many people despise Amateur Radio operators and never aspire to become one. Haughty haughty
You are not tuning for resonace of the antenna when you tune through a random length of coax,
when you tune for resonance at the rig end where you want it lets say 27.205 through random coax,
the coax is cancelling reactance you create in the antenna by tuning the antenna away from resonance,
you end up with what you think is a resonant antenna but with higher vswr than it would be if the antenna was resonant.
antenna self resonace occurs when vswr on the line is lowest.
NightThump is not tuning his antenna wrong. it may be contrary to cb mythology but theres nothing new about that.
when you tune for resonance at the rig end where you want it lets say 27.205 through random coax,
the coax is cancelling reactance you create in the antenna by tuning the antenna away from resonance,
you end up with what you think is a resonant antenna but with higher vswr than it would be if the antenna was resonant.
antenna self resonace occurs when vswr on the line is lowest.
NightThump is not tuning his antenna wrong. it may be contrary to cb mythology but theres nothing new about that.
See, I am an idiot and use an analyzer when all I need is an swr meter. Also solves the problem of reading an analyzer at the antenna without your body screwing with things.
Don't believe Walt what about the mfj user manual,
4.) If the feedline is not an exact multiple of 1/4 wl, the resonant frequency of the antenna might be shifted higher or lower by the transmission line. A mismatched non-quarter wave multiple feedline adds reactance that cancancel antenna reactance at frequencies where the antenna is not resonant.
4.) If the feedline is not an exact multiple of 1/4 wl, the resonant frequency of the antenna might be shifted higher or lower by the transmission line. A mismatched non-quarter wave multiple feedline adds reactance that cancancel antenna reactance at frequencies where the antenna is not resonant.