Tor, N4OGW wrote:
"You CANNOT superimpose POWERS, or even talk about the "power" of
various reflections in the same media."
It is done all the time. P=Esquared / R = Isquared x R.
On page 99 of the 1955 edition of "Electronic and Radio Engineering"
Terman writes:
"The standing-wave ratio S is one means of expressing the magnitude of
the reflectiom coefficient; the exact relation between the two is:
S=1+absolute value of the reflection coefficient / 1-absolute value of
the reflection coefficient
or
absolute value of the reflection coefficient= S-1/S+1
Standing-wave ratio=S=Emax/Emin
This definition of standing-wave ratio is sometimes called voltage
standing-wave ratio (VSWR) to distinguish it from the standing-wave
ratio expressed as a power ratio, which is (Emax/Emin)squared."
Best regards, Richard Harrison, KB5WZI
|