Among the posters on this topic, I'd be willing to bet a substantial sum
that at least Tom, Ian, Cecil, Bill, and I can recite that formula from
memory. In addition, there are a number of other regular and occasional
newsgroup posters in this category who've been wise enough to not having
posted on this thread, and some who have posted whom I don't know well
enough to put my money on. I'd be willing to further bet that Ian,
Cecil, Bill, and I could have done so at any time for at least the last
20 years. I omit Tom from this second list only because I haven't yet
met him in person and otherwise haven't gotten any hints of his age --
but I'll take a gamble and spot him 10 years at least. Furthermore, we
all know how to use it, and have done so countless times in the process
of designing systems that work.

I'm glad you've discovered this equation. Learn what it means and how to
use it, and you've taken a good first step toward understanding
transmission line phenomena.

Roy Lewallen, W7EL

Dr. Slick wrote:
From Pozar's Microwave Engineering (Pg. 606):

Reflection Coefficient looking into load = (Zl-Zo)/(Zl+Zo)

Where Zl is a purely real load impedance, and Zo is the
purely real characteristic impedance reference.

When you change Zo, you change the normalized center of the
Smith Chart, and therefore the Reflection Coefficient and SWR, looking
into the same load.



Check it out...


Slick

Roy Lewallen wrote in message ...
....
I omit Tom from this second list only because I haven't yet
met him in person and otherwise haven't gotten any hints of his age --
but I'll take a gamble and spot him 10 years at least.

Well, you can find archived postings from me from 10 years ago that I
think demonstrate that I understood how SWR meters actually work back
then. And you could probably find my name on a patent that would give
you a clue that I was at least starting to learn a little something
about transmission lines in 1969 or so, though I readily admit to not
worrying about "reflection coefficient" back then. Just hacked
through the raw, unabridged transmission line equations. I suppose
Reg would think that a better way to learn the stuff anyway. I had
bought the King, Mimno and Wing book back then, but didn't get around
to actually reading it till much, much later.

Cheers,
Tom