Richard Harrison wrote:

Keith wrote:
"---it will turn out that there is no value in forward and reverse power
on a line with non-real Zo."

The Bird wattmeter works well enough on coax lines used between the
usual transmitter and antenna. Loss produces reactance in coax. We don`t
seek lossy coax. If it becomes lossy, the line is likely to be replaced.

You, of course, are correct. I overstate the case slightly in
an attempt to get readers to let go of their model. Once they
are free of forward and reverse power as being an accurate
model of reality, they are then free to understand what a
Bird really indicates.

And it is useful for lines with near real impedances (as many
RF lines are) as a TLI. And in cases where reflected power is
near zero, it will even give a hint as to how much power is
being delivered to the load (within 5% of full scale).

The question is, does the reader understand how it works,
why it is useful and its limitation; or does the reader
believe the markings on the scale and think that it is
actually MEASURING the power in a forward and reverse
wave.

....Keith