I have owned a few different autotuners. They are a great convenience,
but not without some cost in performance. The reviews I have seen on
the efficiency of autotuners can be depressing. In fact, I have seen
insertion loss figures as high as 65% on some bands and some crazy
impedances.
I think this is due to the use of toroids and fixed capacitors in
autotuners. A good efficient tuner usually has high Q air inductors
and well made variables. Maybe that explains it, maybe not. However,
they sure do work nice! I used an old SGC at the feedpoint of a 30
foot homebrew vertical. It was a kicker on all bands from 160 through
6 meters! Now, that of course is my own anecdotal experience, and the
antenna may have been inefficient as hell, but it got me on the air and
I got out real well. I have also used autouners on random wires and
such, and again they work well. But expect to lose a fair amount of
power.

In article . com,
" wrote:

I have owned a few different autotuners. They are a great convenience,
but not without some cost in performance. The reviews I have seen on
the efficiency of autotuners can be depressing. In fact, I have seen
insertion loss figures as high as 65% on some bands and some crazy
impedances.
I think this is due to the use of toroids and fixed capacitors in
autotuners. A good efficient tuner usually has high Q air inductors
and well made variables. Maybe that explains it, maybe not. However,
they sure do work nice! I used an old SGC at the feedpoint of a 30
foot homebrew vertical. It was a kicker on all bands from 160 through
6 meters! Now, that of course is my own anecdotal experience, and the
antenna may have been inefficient as hell, but it got me on the air and
I got out real well. I have also used autouners on random wires and
such, and again they work well. But expect to lose a fair amount of
power.

hollycow batman, 65&loss thru the tuner geeewiz i always assumed they
were not totally eff even manual tuners have loss never ever woulda
guessed that bad

think i need to buy some testing gear and see for myself how bad mine
are hope i am not loosing that much

You ain't losing anywhere near that much,, unless it are broke!
Butch KF5DE

ml wrote:
In article . com,
" wrote:


I have owned a few different autotuners. They are a great convenience,
but not without some cost in performance. The reviews I have seen on
the efficiency of autotuners can be depressing. In fact, I have seen
insertion loss figures as high as 65% on some bands and some crazy
impedances.
I think this is due to the use of toroids and fixed capacitors in
autotuners. A good efficient tuner usually has high Q air inductors
and well made variables. Maybe that explains it, maybe not. However,
they sure do work nice! I used an old SGC at the feedpoint of a 30
foot homebrew vertical. It was a kicker on all bands from 160 through
6 meters! Now, that of course is my own anecdotal experience, and the
antenna may have been inefficient as hell, but it got me on the air and
I got out real well. I have also used autouners on random wires and
such, and again they work well. But expect to lose a fair amount of
power.


hollycow batman, 65&loss thru the tuner geeewiz i always assumed they
were not totally eff even manual tuners have loss never ever woulda
guessed that bad

think i need to buy some testing gear and see for myself how bad mine
are hope i am not loosing that much

Again, the high insertion loss is with autotuners into a huge mismatch
on some bands..seems like the higher bands from what I have read.
I don't know this for a fact, only what I read in some reviews along
the way. I think I saw a QST product review or 2 that spec'd this
loss.
The 65% was worse case senario. But the insertion loss was always
higher than a good manual tuner.

ml wrote:
hollycow batman, 65&loss thru the tuner geeewiz i always assumed they
were not totally eff even manual tuners have loss never ever woulda
guessed that bad

A short mobile whip might have a feedpoint impedance of 2-j1500 ohms
yet an SGC-230 will load it just fine. 65% loss (or more) seems
understandable under those circumstances.
--
73, Cecil http://www.qsl.net/w5dxp


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