Richard Clark wrote:
When it is generally accepted that our sources do not exhibit 50 Ohms
source resistance/impedance, what resistance/impedance do they
exhibit?

It doesn't matter. The net power supplied by the source
is *always* the difference between the forward power
and the incident reflected power *by definition*.

The definition seems to assume that 100% of the
incident reflected power is re-reflected *as if*
a 100% re-reflection condition exists.
--
73, Cecil http://www.w5dxp.com