>Dear Antenna Experimenters,
>
>For the 160 meter Contest in December we install a 1/4 wave balloon
>vertical on a ridge in southern MS. We feed it with open wire line.
>A run
>of about 700-800 feet. We have been using a Nye Viking tuner, but it
>isn't
>real happy at times. Two years ago we had to add a small coil to
>tuner to
>get it to work. Last year one of the fixed capacitor plate insulators
>failed, and we repaired it with some sort of plastic we found. We have
>been
>running 500 watts, but may be able to run 1500 watts this year and I
>don't
>know if the tuner is going to take it.
>
>So, is it possible to match this arrangement so we can eliminate the
>tuner?? If so will we be able to have a broad enough match to
>accommodate
>how spread out the band gets during the contest??
>
>If we continue to use the tuner, can we do anything to make the match
>closer to what the tuner can handle?? We usually have 40 60 radials
>of
>various lengths for ground, and I think the soil in southern
>Mississippi
>would be poor ground, although we are only about 15 miles from the
>Mississippi river, but I am not real sure of ground conductivity.
>
>Would a balun at the vertical do any good as far as matching. The
>feedline
>is usually about 6 inches apart so I am guessing about 500-600 ohms
>for it,
>but we can space it closer if necessary or beneficial.
>
>Mike Michon
>AB5XP
Mike, have you considered a coax feedline? I would think that it would be
plenty hard to keep that much open wire feed from radiating and upsetting
the vertical pattern.
CATV hardline would be a good choice since 3/4" has only .15dB loss/ 100'
and by leaving the feed on the ground it is fairly well decoupled. The
final length up to the feedpoint can be RG-11 foam or even RG-6.
Cable reel ends are usually free for the asking and usually even
connectors can be obtained. At 160M even home brew connectors work.
Since I dont know the logistics of your site this is just an idea.
73 Carl KM1H
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