What do you have in the way of aluminum at the top?
There's a lot of influence given by the beam above the half-sloper. I had
a TH6 at 70' and a half-sloper for 80 attached about 3' below it--the lower
insulator was 2" from the farthest corner of the house roof eave. After the
TH6 suffered some damage from a hurricane, I replaced it with the A3 I had
had as a second antenna at 40' on the tower.
The half-sloper suffered greatly with the A3 in place of the TH6. I had to
use a tuner to keep the radio happy on 80 after that. Last year, I replaced
the A3 with an A3S, and more recently, added the 40m option. I also moved
the feed point of the half-sloper up to the top neck of the Rohn 25G pointy
top section--about 1' below the A3S. The half-sloper is now back to being
resonant (or flat) around 3520 and the lower insulator is now about four
feet off the roof!
73 and Happy New Year!
>I must have the only 75 meter sloper that works the first time I put it
>up. I tied the shield to the tower leg a foot below the top, and ran the
>other end (60 ft or so, can't remember, but it was half of a half wave
>dimension at 3.8) to the place where the fence ended. Made the angle at
>the top about 45 degrees. Worked like a champ in Texas. I duplicated
>this set up here in Fla.--ran the end to where the bush was--and it works
>like a champ. Beats a dipole dimensioned interved V most always. Why do
>"they" say it is difficult? (PS my tower is crank up 70 footer, no ground
>at bottom except as via concrete and no other special treatment.)
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