On Thu, 16 Oct 2003 10:00:38 -0700, Jim Kelley
wrote:
Cecil Moore wrote:
Tarmo Tammaru wrote:
There are models for both lossy and non lossy transmission line. I have not
used them, so it might take some learning. I can tell you though that given
a load and transmission line, if you find the Z at the meter with an HP
vector impedance meter, and then put a lumped impedance of that same value
at the meter, you will get the same results.

Not in reality, you won't. Any TV ghosting that exists because of reflections will
disappear when you go to a lumped impedance. And the noise across the lumped
impedance will not be identical to the noise associated with a long transmission line.

Isn't the point just to test SWR dependency on source impedance?

73, ac6xg

Hi Jim,

It "was" but through these twists and turns, the point has become a
amorphous blob.

Tam has shown an appreciation for my interpretation of Chipman's work
being focused on transient analysis (it has that in Chapter 8) and a
worry that my data is forced to that criteria - it is not, it is
strictly steady state results and also supported by Chipman's steady
state formulas (found in Chapter 9).

Chapter 8 reveals the obvious state of a transmission line being
mismatched at both ends supporting a bedlam of wave mixings - the
bedlam is simply the artifact of an unknown length in the path,
otherwise it is quite predictable and formulaic. The steady state
solutions presume you know this length (or in his terms, the position
along the line mismatched at both ends) to find the dependency of
measured voltage in terms of source AND load Z.

Cecil, as usual complains without adding anything:
On Wed, 15 Oct 2003 13:43:39 -0500, Cecil Moore
wrote:
Yes, my experiment seemed to support that assertion but you rejected it.
Where this "seeming" was rejected for good reason (or poor reason
depending upon the source ;-) as he had poorly bounded his example (it
did not include the necessary transmission line which evidences the
source Characteristic Z) and he was forever explaining minutia at the
expense of the topic. 600 posting marathons of that kind of
repetition is unnecessary. My data and sources can stand quite well
on their own without the need for rubber crutches.

Speaking of repetition, this is all covered in my new thread
"The Impact of Source characteristic Z upon SWR measurement - the
Galilean Defense re-revisited"
As such there is actually nothing new to add, and absolutely no
holders of Chipman's work have offered any rebuttal - elliptical
criticism notwithstanding. :-)

73's
Richard Clark, KB7QHC