Roy Lewallen wrote in message ...
If you ever do see an equation which shows transmission line SWR as a
function of source impedance, please let me know where you see it. I'll
add it to my list of untrustworthy sources.

A simple experiment could be set up to disprove it.

Roy Lewallen, W7EL




I believe we are both right, and there is simply a misunderstanding
here.

I believe the source of confusion is he


PA----+----50 ohm line----+SWR meter+----50 ohm line----+50 ohm dummy
load
1 2 3



The "+" are connector points. You folks are saying that as you
change the PA (source) impedance, that the SWR you read will remain
the same, even if the incident power changes due to the change in
reflected power at point 1.

This i can agree with, as no matter how much incident power makes
it past the impedance discontinuity at point 1, the system after this
point will theoretically always reflect the same ratio of reflected
power to incident.
But, if you place an SWR meter of the SAME IMPEDANCE AS THE OUTPUT
of the PA at point 1, you will definitely see a change in SWR at point
1 as you change the PA impedance, as you are changing the reference
impedance (center of Smith re-normalized). This is what i thought you
meant when you said "change the source impedance", but you meant to
say "change the source, but keep the reference impedance the same".

Understood, assuming this is what you guys mean.


Slick