On Fri, 03 Oct 2003 21:41:15 GMT, Walter Maxwell wrote:


Richard, I'm dismayed with your statements above. Are you really serious? Or are
you just giving Cecil a bad time?

That wouldn't take much to push Cecil off dead center.


I've been grappling with your last email to me concerning the nature of the
source resistance of RF amps, and as with your statements above, I'm at a loss
as to how to respond, because we are 180 degrees apart on the source resistance
issue. I'm still going to respond to it, but right now I want to address the SWR
issue.

Richard, how can you possibly believe that the output impedance of the source
has any effect on the SWR on a transmission line?

Stephen Adam of HP using Beatty describes it quite well. The data you
have by email and has been posted here demonstrates it equally well.
It takes no more than two resistors and a length of line to confirm or
deny. My data confirms it, absolutely no one has offered negative
evidence, simply denials.

The only conditions
responsible for SWR are the Zo of the line and the ZL of the load--nothing else.
I've been bench measuring SWR for more than 50 years, beginning with using the
slotted line before more sophisticated machinery was available. It didn't matter
what the source impedance was, the SWR remained the same, whatever the source.
Ian told it like it is, and so does Walter C. Johnson in his "Transmission Lines
and Networks, Page 100, where he says:

If Walter Johnson was not explicit about it, he was certainly implicit
about the requirement that the source match the line it is driving for
any discussion of SWR. This is so commonplace that no one ever
examines the situation where the source is a mismatch.

Too many here simply flip to the section in their favorite book about
SWR and wholly neglect the fundamentals that present this simple
requirement. I have presented quotes, chapter and verse from Chipman
where he explicitly says as much, and those who hold Chipman have
abandoned discussion rather than refute those quotes or accept their
error. As one scribbler put it I was not going to "change his mind."
I have no doubt of that, such a statement paints one into an extremely
embarrassing corner once having uttered it. One thing I learned as a
Metrologist is that I am always wrong, the significance is in the
degree of error, not the philosophy of sin and the rejection in
ignorance.

Any number of correspondents here "might" have the capacity to simply
repeat my methods and report their data; but absolutely none
demonstrate it. I might be so far in error the meter is pegged, but
the quality of "sneer review" absolves me of sin. ;-)

Hi Walt,

I await your response by email for our last round of discussion. What
is presented above is old material already discussed. There is
nothing new presented by me in it that has not found its way to your
mailbox.

73's
Richard Clark, KB7QHC