Owen Duffy wrote:
"Jeff" wrote in
e.com:

Owen and Cecil are right: the source (transmitter) has no effect
whatever on the VSWR on the line.

That isn't just an assertion - it is part of the bedrock transmission
line theory. Owen referred to "reputable textbooks", one of which
would surely be 'Theory and Problems of Transmission Lines' by R A
Chipman [1]. This book gains a lot of its reputation from its very
complete mathematical development of the theory, showing all the
detailed working.

I am sorry but you are not correct, I have not read Chipman so I
cannot comment on his analysis or your interpretation of his results,
but my understanding , practical experiments and CAD analysis would
lead me to disagree.


[...]

Looking at it another way, the vswr changes sinusoidally with
frequency, in our example, between 2:1 and 8:1. (The same as the Smith
chart plot with a circle of radius 4 centred at about 0.6).


If you are asserting that VSWR on a real or even theoretical line varies
sinudoidally with displacement, it is time to go back to basics. You need
some time with a reputable text book.

Agreed, but make that a textbook that specifically deals with the
subject in enough detail. Chipman was highly recommended by contributors
to earlier rounds of this debate. It isn't an easy read, but it's
certainly thorough.

I ordered the book from the other side of the world because I wanted to
be very sure of my answers next time around. We don't know where you
are, Jeff, but it would probably be easier and cheaper for you to do the
same.



--

73 from Ian GM3SEK