Roy Lewallen wrote in message ...

Absolutely incorrect. Time for you to review your Smith Chart
again.

Here's an experiment for you to try.

On your workbench, measure the characteristic impedance of a cable, or
connect it to a source or load and measure the SWR on it. Now go over to
your desk, take out your grease pencil, and change the reference
impedance of your Smith chart. Go back to the bench, check the SWR and
the cable Z0. Has it changed?


Do you often change the impedances of your equipment by scribbling
on a pad of paper? Maybe you can tell us how you do this.



If *you'll* review the Smith chart again, you'll find that *if* you set
the reference impedance to the Z0 of the transmission line you're
analyzing, then the SWR, impedances, and so forth that your read from
the Smith chart are correct. If you set the reference impedance to some
other value, an SWR read from the chart certainly isn't the SWR on the
transmission line.



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



Once again, if you placed an SWR meter of the same output
impedance of the PA at point 1, you will measure the SWR at point 1,
and it would be akin to re-normalizing the Smith. Change the PAs S22
(and the impedance of the SWR meter, and you will definitely change
the SWR at point 1. Do you agree with this?

I've already agreed with you that the SWR at point 3 won't change
in theory, as it is surrounded by 50 ohms. What is it about this
simple concept that you cannot seem to understand?




Thank you, although I'm not an expert at using the Smith chart, I know
my way around the circle.


It's obvious you don't. Time to read up on it, Roy.



I am always interested in learning. I don't use a Smith chart a great
deal,


Obviously.


Slick