I avoided the traps and tuning struggles by erecting separate 1/4 wave
INV-L's ( one for 160m and one for 80m.). Then drove one 8 ft ground
rod into this midwest farm soil ( moderate conductivity) and
supplemented that with 26 radials for 160m only. ( lengths between
30-130 ft depending on property line proximity. In summer mowing
season I could the radials and work off the single ground rod with
excellent success.)
My support is a 55 ft tall black walnut tree ( which secrets a unique
acid to kill other nearby trees/ plants in its root system. I suspect
the acid aids soil conductivity and accounts for the better than
expected performance with a single ground rod. Who'da thunk?
I use a single coax feed to the base of both antennas, through a coke
bottle inductor that I play like an accordion (expand or contract) for
best SWR. My chosen band is 160. 80m loads up about as well
....typically 1.5 or less at resonance. I use a manual HF antenna
tuner in the shack ( 350 ft away thru RG213.) for wide excursions on
both bands when necessary.
Each antenna performs independently of the other despit being only a
few feet apart on the vertical legs, then pulled out about 90 degrees
apart at around 45 degrees downward slope.
186 DXCC entities worked on 160 . I use the 80m leg to chase new dx or
for contest fillers, working into VK/ZL/JA/ZS/KH6/UA0 without
problems.
The spooky thing is it works almost as welel off the single ground rod
as it does when the 26 radials are unfurled. Both my antennas are set
for the cw band. 2:1 points are 1800-1870 khz, and on 80m BW is c. 100
khz.
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