Roy Lewallen, W7EL wrote:
"No, the Bird wattmeter measures only the average power and only at one
point."

True. The Bird wattmeter measures average power, the same as any a-c
wattmeter, and only at the point of measurement. If the line is lossy,
the numbers are higher near the generator, and difference between
forward numbers, for example, is an indication of loss between insertion
points.

Best regards, Richard Harrison, KB5WZI