Owen Duffy wrote:
- that V/I=Zo for a travelling wave in a transmission line, and that
(Vf+Vr)/(If-Ir) at the load end of the line must equal Zload;

It seems that we can draw some conclusions from these
assumptions.

Vf*If*cos(0) = forward joules/sec

Vr*Ir*cos(0) = reflected joules/sec

The forward and reflected energy waves actually exist
and are the building blocks of the standing wave.

Vf and Vr are phasors and therefore subject to
superposition and interference.
--
73, Cecil http://www.w5dxp.com