actually, thats not entirely everything.

example:
feed a radio into a 3:1 mismatch without a tuner and roughly 25% of your signal reflects back to the radio. as a result, the finals start to heat up and produce less power (until they they enter thermal runaway and fail). The other side effect of this mismatch is that more than 25% of your signal never gets radiated (due to the mismatch between antenna and feed line).

Now, add a tuner to the mix:
adjusting to lowest reflection, the radio operates more efficiently and thus more power can be transferred to the line. the antenna will still see a mismatch, but because you are now using the tuner, the line becomes part of the antenna (its the same as using a tuned line to match to a non-resonant antenna). The effect here is that more of your signal actually gets on air (though not as much as if the antenna were resonant).

On a properly working tuner, the insertion loss to the line should be less than .5 Db. Any losses as a result of mismatch will tend to be absorbed in the line itself (as heat). If the line is actually short enough at the operating frequency, it can be largely discounted as a loss element (the length of the line should be under 1/4 wave for this to happen). also, one other interesting fact, at a quarter wave, the coax will act as a line impedance transformer (it will exhibit a very high impedance with respect to the transmitter end of the line). Use of an antenna tuner in such a situation will often result in most of the power to the antenna being radiated.

-eric
n7zzt

On Jun 30, 2014, at 11:31 AM, Butch Bussen wrote:

> The tuner simply matches whatever to the radio, in other words, it makes 
> the radio happy.  You will always lose a little through a tuner.  It 
> really doesn't make the antenna radiate any better.  You can hook your 
> radio up to a dummy load and it is perfectly happy, but you won't 
> receive or transmit very far. HTH.
> 73
> Butch
> WA0VJR
> Node 3148
> Wallace, ks.
> 
> 
> On Mon, 30 Jun 2014, David Pearson 
> wrote:
> 
>> Hello List:
>> 
>> A previous post suggested that an antenna tuner "fooled"an antenna into
>> thinking that the antenna was resonant on a particular band/frequency(I
>> think that he was referring to verticals).
>> 
>> My question concerns multi-band wire horizonntals(a 10-40 half-size g5rv for
>> example).
>> 
>> In this situation, is an antenna tuner performing the same function as it
>> did with the vertical("fooling" the feed system into believing it's matched,
>> or does it perform some other positives(better power transfer, etc.)?
>> 
>> Sincerely yours,
>> 
>> 
>> 
>> David S. Pearson-wa4dsp
>> 
>> 
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