I'm having trouble with my shunt-fed 15m tower. I have an L matching
network that is switched between 80 and 160m. A relay selects
different taps on the inductor, and also adds capacitance for 160m.
If I use an MFJ 259 antenna analyzer, I can get a nice match on
either band. And if I transmit with a few watts, I have no problem.
Even the 20 watts that the KAT100 uses isn't a problem.
However, if I transmit about 70 watts or more, the SWR suddenly
shifts to 3:1 or worse. It changes with each transmission.
I thought the caps might be arcing, so I replaced one of them with a
wide-spaced variable, same problem.
Bill Coleman, AA4LR, PP-ASEL Mail: email@example.com
Quote: "Not within a thousand years will man ever fly!"
-- Wilbur Wright, 1901
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