Cecil Moore wrote in
:

Owen Duffy wrote:
You assertion that you have travelling forward and reflected power
waves on the transmission line runs into a problem when you try to
analyse the combination of both at a point (eg the input to the line)
as power doesn't combine vectorially.

But it does combine according to the following formula
which is the irradiance equation from the field of
optics.

Ptot = P1 + P2 + 2*SQRT(P1*P2)cos(A)

where 'A' is the angle between V1 and V2 and V1 is
the voltage associated with P1 and V2 is the voltage
associated with P2.

Cecil,

A is not a property of P1 or P2, and cannot be derived from them. I
maintain that you cannot vectorially combine P1 and P2.

Owen