"Antonio Vernucci" wrote in message
. ..
Along several decades of radio hamming on the HF bands, I noted that the
measured SWR of all the antennas I have mounted (Yagis, dipoles) slightly
varies when the feedline length is changed by several meters. For 100W of
forward power, the reflected power could vary somewhat, e.g. from 2W to 5W
or so, measured on a Bird wattmeter. This behavior would seeem to deny the
theory, according to which SWR is independent of feedline length (as long
as the cable attenuation remains constant).


Surely this sounds about right for a Bird 43. Assuming a directivity for the
meter of 30dB and an swr of 1.4:1 this would give a possible indicated
return loss of between about 13 to 16dB depending on the relative phases of
the forward and reflected signals. So moving the meter would give an
indicated reflected power anywhere in the 2 to 5W range.

73
Jeff