Roy Lewallen wrote in message ...

let me rephrase:

PA----+SWR meter1+----50 ohm line----+SWR meter2+----50 ohm
line----+50 ohm
(50 Ohms)
dummy

load
1 2 3


If you measure the SWR at point 1, you let Z1 be 50 ohms, and Zo
is the output impedance of the PA. SWR meter1 should be characterized
to Zo.

I've agreed that SWR meter2s SWR reading will not change as you
change PAs impedance, but the SWR at point 1 definitely will.

So, Does the SWR change as you change the source impedance? IT
DEPENDS ON WHERE YOU MEASURE IT!

From Pozar's Microwave Engineering (Pg. 606):

Reflection Coefficient looking into load = (Zl-Zo)/(Zl+Zo)

It should be easy to see from this well known equation that a
perfect 50 Ohm Z1 will definitely change SWR as you change Zo away
from 50 ohms.


Slick


BTW Roy, comparing someone to the intelligence of your adolescent
kid who waits for trains because you told him you are an engineer is
indeed an insult.