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

As far as I'm concerned, Gamma is the complex reflection coefficient;
rho is its magnitude.

That works as long as everyone else understands what you
are talking about. Here's a quote from:

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

"The SWR meter is only concerned with the magnitude of the
reflection coefficient, but rho is a complex quantity having
both a magnitude and angle. If rho were to be measured at
various points along a transmission line, the magnitude would
be fairly constant but the angle would change depending on
the electrical length of the line at the point of measurement."

And from the "ARRL Antenna Book":

"In some professional literature, Gamma is used in place of rho
to represent the reflection coefficient."

Wes, you must be a professional. :-)
--
73, Cecil http://www.w5dxp.com