Owen Duffy wrote:
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.

P1 is a property of V1^2/Z0, A is a property of V1.
P2 is a property of V2^2/Z0, A is a property of V2.
There is an unbroken chain of cause and effect.
It is true that one cannot directly vectorially
combine P1 and P2 because P1 and P2 are not vectors.

However, the ability to combine the P1 and P2 of
coherent EM waves dates back to before you were born.
Optical engineers didn't have the luxury of being
able to measure the phase angles. All they could
measure was the total amplitude. Please don't try
to tell us that their total amplitude measurements
were wrong throughout the 20th century and are
still wrong in the 21st century.

The rules for combining P1 and P2 when they are
coherent are known as the irradiance equations in
optics. Dr. Best applied them to RF quantities.
Please reference "Optics", by Hecht, 4th edition,
page 388 and Dr. Best's, "Wave Mechanics of Transmission
Lines, Part 3: ..." in the Nov/Dec 2001 issue of "QEX".
--
73, Cecil http://www.w5dxp.com