AA1K:
> Without these chokes, all the feedlines going up the tower would
> effectively make it a grounded tower. With the chokes, it is like the
> feedlines aren't even there and works just like a series-fed tower should.
I had a similar experience on my series fed tower. It was a 130ft tower
made of Rohn 25G. The insulating section was 10ft up. The tower was
inductive (too long) due to the leaky power line insulators, and an 8
element log on top. It resonated at 1400 kc.
I initially tried to "choke" the feedline to the log periodic with 8 large
ferrite cores (1.25" long X 1" diameter) with no result.
I then wrapped 100ft of RG-58 around a 5 gal pickle bucket, and that did the
trick. I started taking wraps off in increments and found around 60 ft of
coax did the trick.
I then went back to the ferrite, realizing I needed more cores. I put 36 of
them on the line, and they just started to show a positive effect.
The tower was very reactive on 160, if it was resonant, I would assume
fewer cores or less coax would be needed.
At the time I didn't want to go to the expense of extra line for coils, so
I built a switch that opened all the lines across the insulating joint, when
I was on 160.
Jay W7CW in Wyoming
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