On Tue, 27 Feb 2007 21:14:38 GMT, Owen Duffy wrote:

I am also aware that supporters of the inherent source match position
assert that you must be selective in choosing tests for source impedance.
It is all rather unconvincing when only some of the implications of a
particular source impedance are effective.

It is my view that modelling the PA as a fixed voltage or current source
with fixed source impedance of Zo, and where reflected waves on a
transmission line are absorbed by the matched source is not a good
general model for HF PAs.

Hi Owen,

This quote gives me no confidence in what you have offered to me
recently:

On Wed, 28 Feb 2007 08:55:24 GMT, Owen Duffy wrote:

You have not yet actually offered any treatment that denies the bone
of contention that lies in two subject lines:
1. Reverse power is manifest;
2. The source will absorb and dissipate it.

Richard, if you go back over my postings in this thread, I have not denied
either of these things.

As to point 1 (or 2 it is difficult to determine what you are
responding to specifically), explicitly stated by me, you have
expressed your self in relation to "supporters of the inherent source
match position" without actually identifying if you stand
1. With them;
2. Against them;
3. Indifferent to them.

As to point 2, explicitly stated by me, you have again described
yourself in a negative relation by discussing a model that does not
work.

Perhaps it is this style of ambivalence that clouded my appreciation
of your statement:
I believe that it is sound (in the steady state) to resolve the forward
and reflected wave voltages and currents at the source end of the
transmission line, calculate the complex impedance, and predict the
effects of that impedance as a PA load using the same techniques that
were used to design the PA.
where you do allow 1 and 2.

However, I could be mistaken again because you don't actually
acknowledge return power impinges upon the final stage, you transform
it into another solution. Note that I accept such a transformation of
the problem. It is common alternative explanation and perfectly
valid. However, that transformation, in and of itself, does not speak
to the issue of reflected power as a physical fact and a separable
entity. In fact, the development of a lumped equivalent doesn't need
to acknowledge SWR either.

73's
Richard Clark, KB7QHC