TTs,
A couple of us spent the day today trying to get a shorty tower loaded
for 160m. Specifically, the tower is 42 feet tall with 4 feet of mast
out the top. On top of the tower is an XM240 2 element 40m beam. The
reflector is not grounded to the boom.
Being that I sit on top of decomposing granite (IE: the Colorado
Rockies), there isn't such as thing as Earth ground. We were able to
string out twelve 64 foot radials. These are either just laying on the
ground (in the wooded areas) or just under the surface in the "yard".
We originally started with 1 shunt made of 1/2" copper tubing 6" from
the face, but ultimately went with two shunts of 1/2" copper tubing
spaced 1 foot from the tower face. It seemed no matter what combination
we tried (just inductance, just capacitance, and both), we could not get
any resonance for 160m. We were able to find a chunk of 80 that gave me
about 100 khz with reasonable SWR.
I see that guys have made "shorty" towers work on 160 but just could not
find the magic combination today. So I defer to the experts for
suggestions.
73
Kelly - N0VD
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