Richard Harrison wrote:

Jim Kelley wrote:
"That`s because power doesn`t propagate, I hasten to add - neither do
Poynting vectors.:

Some world-class experts disagree with Jim. Here is a sample quotation
using the words "power flow".

From E.M. Purcell writing about "Antenna Gain and Receiving Cross
Section" on page 19 of "Radar System Engineering" edited by Louis M.
Ridenour:
"If the transmitting antenna were to radiate energy isotropically-that
is, uniformly in all directions-the power flow through unit area at a
distance R, from the antenna could be found by dividing P, the total
radiated power, by 4piRsquared."

Best regards, Richard Harrison, KB5WZI

There's nothing wrong with calculating the power per unit area at any
point in a transmission line. I'm sorry if I gave some other
impression. The problem I have is with believing that the calculated
value propagates as if it were an electromagnetic field. The Poynting
vector is useful for making calculations, but it not a useful tool for
explaining the behavior of natural phenomenon.

73, ac6xg