Roger Sparks wrote:
We have to have a starting point, which must be the source power. How could we avoid having a starting point?

We are analyzing a resistor isolated from the source and load
by 1WL of ideal feedline on each side. All we need are the
steady-state values of Pfor1, Pref1, Pfor2, and Pref2. It's
much like an s-parameter analysis of a 4-terminal box with
a 50 ohm series resistor. If we know a1 (Vfor1) and a2 (Vref2),
that is all that needs to be known to complete the analysis.
We don't actually need to know anything about the source and
the load if a1 and a2 are given.

I think this equation is missing some terms, reflections 2,3,4...n.

The equation already contains all of those "missing'
terms because it is steady-state and all of those
terms have already been added in to the total.
--
73, Cecil http://www.w5dxp.com