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Old April 19th 07, 12:10 AM posted to rec.radio.amateur.antenna
Jim Lux Jim Lux is offline
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First recorded activity by RadioBanter: Mar 2007
Posts: 801
Default Why S - Parameter at High frequencies?

Cecil Moore wrote:
Owen Duffy wrote:

So, what you are referring to with the term "virtual reflection
coefficient" is the magnitude the reflection coefficient (rho). or |(Z02-
Z01)/(Z02+Z01)| (Gamma).



I believe the following web page is indicative of
how Gamma has essentially been replaced by rho.

http://www.ac6la.com/stss.html

The ARRL Antenna Book implies that rho is used
by amateur radio operators while Gamma is still
used in some professional circles.


"still used"... I don't know that expressing reflection coefficient as
gamma is an archaic notation. You see it a lot in performance
specifications for RF test equipment like network analyzers. Where the
magnitude is meant (and Gamma isn't real) you'd see it written with
vertical bars on either side ||.

For instance, in the latest Agilent PNA manuals, they use capital Gamma.

here's an interesting interactive smith chart
http://www-ece.eng.uab.edu/JCaldwel/...art/SChart.htm


lower case gamma is used for the complex propagation constant in
transmission lines.