Jim Kelley wrote:

"Cecil Moore" wrote:
rho = +1 means there is a zero degree phase shift in the reflected voltage.

rho = -1 means there is a 180 degree phase shift in the reflected voltage.

So in other word the sign sometimes indicates phase, and other times
indicates a direction in propagation depending on which hand is waving..
Thanks.

Consider the equation, rho = (ZL-Z0)/(ZL+Z0). If ZLZ0, then the
voltage reflection coefficient is positive and there is no reflected
voltage phase shift. If ZLZ0, then the voltage reflection coefficient
is negative and there is a 180 degree phase shift in the reflected
voltage. The same holds true for the E-field of reflected light.

The RF reflected current convention differs from the reflected light
H-field convention. Kirchhoff's current convention enters into the sign
of the reflected RF current where no such convention exists for light.
--
73, Cecil, W5DXP