"Walter Maxwell" wrote in message
...
Tam,

I totally disagree with those who say SWR appearing on a mismatched
transmission
line is dependent on the source impedance.

Walter, I agree with you. But I am making a distinction between SWR and
*measured* SWR. People who think an SWR meter possesses magic properties
should look inside one. It takes one instantaneous sample of the NET voltage
V, and one instantaneous sample of the NET current I. It displays the vector
sum of
K(V + k2I)
and
K(V- k2I)

where K is the sensitivity, and k2 is chosen to make the second equation
equal to 0 for a 50 Ohm load. The approximations made in coming up with what
is printed on the meter scale assumes that for the forward wave the voltage
and current are in phase. I have seen descriptions of how these things work,
but no equations to back these up. I suspect one would start with the two
equations that I listed, but express I in terms of V and deltaZ, where
deltaZ is the deviation from 50 Ohms. K can arbitrarily be 1. I also suspect
that Bird, etc don't really want us to know that.

Tam/WB2TT