On Fri, 23 Mar 2007 19:30:56 GMT, Walter Maxwell
wrote:

I don't understand what you mean by 'taking only one
of two degrees of the 360.'

Hi Walt,

I offered:
they take only one or two degrees of the 360.

Arguments that are confined only at 0 or 180 (the one OR two degrees)
and are submitted as proofs as though they boxed the compass. All too
often I've seen one condition (at one phase angle) offered as a
negation of internal heating to prove the source lacks its own
internal resistance. When I've taken exactly the same circuit and
explored the 180th degree alternative, I've demonstrated melt-down
clear and simple. The dissipation of energies does not always lead to
this consequence, but if we were to average the analysis over a
complete 360 degrees, we can only arrive at the obvious evidence of
resistance and calories expended.

But even for coherent reflections, if the PA tank circuit has very low loss
for incident power (which it does), why does it not have ~ equally low loss
for load reflections of that power? Such would mean that load reflections
would pass through the tank to appear at the output element of the PA, where
they can add to its normal power dissipation.

The paragraph above seems to me to imply that RF doesn't understand the destructive and constructive
interference phenomena involved with re-reflection.

Then asking a question to clarify would be in order. To me, it reads
quite ordinarily as a statement of symmetry. In my own words, it
would say that if a tank circuit can pass energy from source to load
in one direction, it can certainly perform the same transformation in
the opposite direction. After all, that is the function of
transformation and a passive circuit composed of L and C is strictly
linear. Circuit analysis allows us to treat a load as a source in the
complete circuit description.

This is the symmetry of the illustration of external signals. You
used external signals yourself as part of your case study; hence the
relevance has been made by you.

Whoa, Richard! You'll have to point out where I've discussed external signals in any case study involving
phase relationships between forward and reflected waves. I've never done so knowingly.

It seems to me that in your initial post in the original thread (that
was largely ignored for comment) you made mention of injecting a
signal from an external source into the mouth of the dragon for the
purposes of measuring the source Z. Am I wrong?

And we return to the sine non quo for the discussion: phase.

That's true, but although RF apparently realizes that the phase relationship is relevant, he doesn't seem to
understand the details of the phase requirements that achieve the necessary interferences that accomplish the
impedance matching.

That is not what I read.

It seems he is on the face of it, doesn't it? Afterall, he is quite
explicit to this in the statement you are challenging.

No Richard, I don't believe he is. I don't see the 'explicitness' you seem to find. It's the complete lack of
the explicitness that makes me believe he doesn't quite get it.

That has not been my impression of the complete post.

Nothing here contradicts anything either of you have to say.

True, but RF just hasn't said it all, because, as I said above, I don't believe he understands the details of
the phase requirements to achieve the match.

That has not been my impression of the complete post.

This phenomenon occurs in all tube transmitters in the ham world when the tank circuit is adjusted for
delivering all available power at a given drive level.

This introduces the two concepts of the "need for match" and the
"match obtained." They are related only through an action that spans
from one condition to the other. They do not describe the same
condition, otherwise no one would ever need to perform the match:

I don't comprehend your statements in the paragraph above.

The initial mismatch and its correction do not describe the same
condition. There is a first state, and then the operator imposes a
second state in reaction.

If a tree were to fall onto the antenna, a new mismatch would occur.
Would the transmitter faithfully meet the expectations of the Ham
unaware of the accident? No, reflected (0-179 degrees) energy would
undoubtedly offer a 50% chance of excitement in the shack. The
consequences of dissipation would be quite evident on that occasion.
For the other 180 (180-359) degrees of benign combination; then
perhaps not.

If a tree were to fall onto the antenna the new mismatch would surely detune the transmitter, causing unwanted
dissipation, of course, but only a lid would fail to retune the transmitter before removing the tree.

Of course, but then this is a single instance: a mismatch causing
possible increased dissipation within the source. "Possible" is in
proportion to phase relationships; dissipation is always.

If you retune to correct the mismatch's potential to destruction (or
to provide full power through-put); then you have moved to another
state or configuration. That new state admits the potential negative
consequence of the first state.

IMHO, Richard, the mfgrs of solid-state rigs with no means of matching the output to a load other than 50
ohms short changed the ham, thus requiring him to be satisfied with the power fold back, or buy an antenna
tuner.

A tube rig requires the same means of matching. It's a wash.

73's
Richard Clark, KB7QHC