On 6/24/2020 11:20 AM, Steve London wrote:
Is there another solution I am overlooking ?
Hi Steve,
Yes. Feed the two antennas separately. Use a stub in the 80M feedline as
detailed here to kill the harmonic of 80 on 40.
http://k9yc.com/LocatingStubs.pdf and
http://k9yc.com/StubPlacement.pdf
The same stub, properly placed, will apply a short at the feedpoint of
the 80M antenna, which should kill the interaction. I learned this a few
years ago doing an NEC model of our contesting trailer's antenna system
k9yc.com/7QP.pdf I work with N0AX on the Handbook and Antenna Book, and
when I told him what I'd learned he nodded his head yes, he'd known
about that for years. The ancients keep stealing our inventions. :)
Also, remember that VF varies enough with frequency that stubs must be
measured and tweaked to length at the frequency where you want them to
be a short. The variation is enough to move their resonance to a
different part of the band.
73, Jim K9YC
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