>> What I HAVE done (about ten years ago) was to add a second #10 THHN
>> to my Tee vertical for 160M, spaced roughly 8-10 inches from the
>> first, wired in parallel top and bottom.
I use "LadderSnaps" to create a thick radiator. Although LadderSnaps are used
to make 600-ohm open line feeders, they work well for this purpose. Simply tie
the two conductors together at the top and bottom.
My 160m T is 100 ft high with an 80 ft. flat top. Next season, the flat-top
will increase to 120 ft. where RF current magnitude is uniform across the
entire radiator length with a slight current peak half-way up.
I initially selected an 80 ft top because it made matching super easy. The
base Z is 50+j200 and only requires a series capacitor to achieve a 1:1 SWR.
The series cap will be replaced by a low-pass L network as the R value is
expected to rise up to about 65 ohms. Resonance presently occurs at 1500 kHz
but will shift down to 1400 kHz when the flat-top length increases. Easy to
match with a low-pass L network.
Paul, W9AC
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