"Henry Kolesnik" wrote in message ...
I'm probably not the only one that is getting an adequate fill of facts,
opinions and quotes. I have only one request. Does anyone have verifiable
and repeatable evidence that a properly tuned pi network final amplifier
without a tuner does or does not dissipate power when there are reflections?
If they do can they please direct us to the source or give us an easliy
understandable write up.


If you read Chapter 13, "RF Power Amplifiers and Projects", in the
2004 ARRL Handbook, there are pages and pages of discussion of
matching plate or transistor output impedances to 50 ohms output and
not once do they ever refer to output networks dissipating or
reflecting reflected power. Not once. It's always a matter of simply
matching one impedance to another to provide the highest power output
consistent with required linearity, while staying within the
amplifiying device's ratings.

Transmission lines have reflections; output matching networks and
tuners don't. The reflections on transmission lines don't make it past
the end of the transmission line -- that's where the reflections take
place. Beyond the end of the transmission line, the reflections are
seen as mere impedances created by standing waves, which are created
by reflections, assuming mismatch.

Al

Henry Kolesnik wrote:
I'm probably not the only one that is getting an adequate fill of
facts, opinions and quotes. I have only one request. Does anyone have
verifiable and repeatable evidence that a properly tuned pi network
final amplifier without a tuner does or does not dissipate power when
there are reflections? If they do can they please direct us to the
source or give us an easliy
understandable write up.

Sorry, Hank, I don't believe you can hope for that.

In all innocence, you have rigged the question so that it only allows
certain kinds of answers. It has to be a pi network. It has to be
"properly" tuned. There have to be reflections.

The question is tied up so tight by its built-in assumptions - the
things you believe you already know - that there may not even *be* a
correct answer.

Time after time, this same discussion about "reflected power" fails to
reach any agreed answer. Time after time, we run the same maze like lab
rats... only more predictably... and every time, we fail to reach the
goal of a clear, agreed understanding.

And the conclusion of these experiments? That the concept of "reflected
power" is not helping us to understand anything.

The irony is that nobody actually *needs* that concept, so you don't
ever *need* to enter that maze. Everything about standing waves on
transmission lines can be understood much more clearly by thinking only
about forward and reflected voltage/current waves.


--
73 from Ian G3SEK 'In Practice' columnist for RadCom (RSGB)
http://www.ifwtech.co.uk/g3sek