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[AMPS] conjugate match and amplifiers

To: <amps@contesting.com>
Subject: [AMPS] conjugate match and amplifiers
From: realex@flash.net (Bob Alexander)
Date: Tue, 09 Sep 1997 20:10:19 -0500
Tom,
Thank you for e-mailing me a copy of "Source Impedance of HF Amplifiers
and the Conjugate Match".
You asked me to let you know what I think of it, so here it it.

After I downloaded the E-mailed file, I spent about an hour inserting
line feeds into the text 
to format it in a way my word processor can handle.  The result was 22
pages of close spaced, 
small print not the 7 pages mentioned in the Amps posting.  The
illustrations were missing but
not really necessary.

After I read all 22 pages I was more than a little surprised by what I
had read.  So much so, in
fact, I read through it a second time to make sure I had not
misinterpeted what I read.

I feel the paper is more  a personal attack on Warren Bruene, W5OLY,
than  an attempt
to revive a discredited theorum.  As for the "proof" offered in support
of the authors assertions,
once the references that have nothing to do with the topic at hand are
eliminated, and the obvious
obfuscations removed, there is little left except for the attacks on
Warren.

Get rid of the attacks and the remainder is easily disposed of with the
following statement by
Walt Maxwell on page 19-7 of "Reflections, Transmission Lines and
Antennas".

QUOTE: "... In the classical generator, the optimum load resistance
required for delivering
the maximum available power is always equal to the source resistance of
the generator, as
required for a conjugate match.  However, because of the complex nature
of various relationships
between voltages and currentsin an RF power amplifier, during normal
operation  the internal
source resistance of the amplifier, Rs, is almost never equal to the
optimum load resistance, Rl.
Hence, because of the different values of resistance existing between
the source and the load when
we complete a matching operation, we do not have a true conjugate match
when an RF amplifier is coupled
to an antenna tuner or feed line. ...in reality, the tuner or feed line
is matched to the optimum
load resistance of the amplifier, but it is conjugately mismatched to
the source resistance."


Have a nice day,
Bob, W5AH

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