Fellow TTer's: Problem - Have a 2 element yagi on 40 M that is currently
tuned for the CW end of the band. In order to use it on the SSB end, past
techniques have included locating a Transmatch at the base of the tower and
adjusting the match so the amplifier can tune properly - this has proved
difficult as it was inconvenient to re-tune for other portions of the phone
band (tower base is 300 ft. from the shack and the bandwidth with the tuner
was not too great); another approach used was to locate the tuner in the
shack - made it convenient to re-adjust as necessary, but caused severe
voltage breakdown conditions on the feed line (high SWR plus the amplifier
proved disasterous for connectors).
What are others doing to make the SWR better on the opposite end of the
band the antenna was originally tuned? Have considered adding stubs
somewhere on the feedline, but have not tried as yet. Looking for a way to
allow the amplifier to tune properly across the entire phone band even
though the antenna's performance is degraded due to a non-optimzed setting
of the elements for that part of the band. 40 M phone is not my favorite
but with this problem fixed, I can at least make a better score in those DX
contests. (That's the plan anyway!)
I realize this is transmission line theory 101, but thought there might be
a quick answer out there!
The yagi is a Cushcraft 402 at 100 ft. fed with 3/4 - inch diameter 75 ohm
hardline (300 ft. plus 100 ft. up tower).
Regards,
Mark, K1RX
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