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Old June 2nd 09, 04:38 AM posted to rec.radio.amateur.antenna
Owen Duffy Owen Duffy is offline
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First recorded activity by RadioBanter: Dec 2006
Posts: 1,169
Default SWR variation with feedline length

"Antonio Vernucci" wrote in
:

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).


Tony,

You may find my thoughts at
http://www.vk1od.net/transmissionlin...splacement.htm of interest.

Owen