"Roy Lewallen" wrote

But we seem to now have a "true SWR" as opposed to
some other kind of SWR. And "true SWR connected to
the tx output" doesn't have any meaning at all to me.

My "true SWR" term is used is an attempt to differentiate between the SWR of
the antenna system, and the inaccuracies associated with trying to measure
it with devices that cannot isolate the incident power in the system from
internal reflections of that power. For the conditions and reasoning
outlined in my earlier posts in this thread, and even though the system SWR
is a constant -- the normal SWR meter used in/with an operating transmitter
working into a mismatched load won't have the ability to give strictly
accurate measurement of that SWR. That is all I'm saying.

I also have no idea of what "sample points within the
transmitter" might be.

In broadcast gear, these are the directional couplers whose pickup probes
are inserted transversely into the coaxial line between the harmonic filter
output and the tx output connector. I haven't been a licensed ham for over
40 years (when I went into the broadcast field), but I expect some ham txs
might have the same setup. Otherwise it could be a Model 43 or the like
inserted between the output connector of the ham tx and the transmission
line to the antenna.

I hope this is understandable now.

RF