"walt" wrote in news:1173278086.390893.310040@
30g2000cwc.googlegroups.com:

On Mar 3, 4:37 am, Richard Clark wrote:
On Sat, 3 Mar 2007 00:10:21 +0000, Ian White GM3SEK
....
I've been reading this thread with interest, but the discussions
appear to be only academically related. On the other hand, I've made
measurements that prove the sailent points of these academic
discussions. These measurements were made since those reported in
Reflections 2, and will appear in Reflections 3. However, they are
available on my web page at www.w2du.com. Go to 'Preview of Chapters
from Reflections 3' and click on Chapter 19A.

You may want to disregard the first portion of the chapter, which is
an epilog to Bruene's fiction concerning the conjugate match. The
pertinent portion here is that which reports in detail the step-by-
step procedure in measuring the output impedance of a Kenwood TS-830S
transceiver feeding a reactive-impedance load.

With a careful review of these steps I'm sure you'll find empirical
proof of the academics appearing in the previous posts.

Hi Walt,

I have read your document with interest, and will reread it a couple of
times yet.

The measurements are interesting, and on a first read, appear consistent
and in agreement with how things work as I understand it.

However, I don't believe any of your measurents actually reveal the
source impedance. You have shown the impact of the changed load on the
transmitter. You have demonstrated admirably the transformation of the
two external loads to the load seen by the plate(s), and you have shown
what the transmitter looks like from the antenna socket with a resistor
in place of the valves.

So, IMHO, the promise "The output source resistance of the amplifier in
this condition will later be shown to be 50 ohms" is not fulfilled.

It is my view that the statement "Because the amplifier was adjusted to
deliver the maximum available power of 100 watts prior to the resistance
measurement, resistance RLP looking into the plate (upstream from the
network terminals) is also approximately 1400 ohms" is not proven.

If we were to view the plate as a generator, and the pi network as a
lossless flexible variable impedance transformer, and you were to adjust
the pi network for maximum power transfer, that would imply that the
impedance loading the generator was the complex conjugate of its
equivalent series resistance... IF and ONLY IF the generator can be
accurately represented by an equivalent series circuit of a fixed voltage
generator and fixed equivalent series impedance.

The question is can the plate (or the whole transmitter for that matter)
be accurately replaced by an equivalent series circuit of a fixed voltage
generator and fixed equivalent series resistance (independent of load).

How would such a simple model deal with the case of a transmitter that at
maximum power output is close to voltage saturation (ie cannot develop
more output voltage) and close to current saturation (ie cannot develop
more output current)? These non-linear behaviours close to operating
point are not captured in a simple linear equivalent circuit.

Owen