On 2018-09-13 10:50 AM, Herbert Schoenbohm wrote:
If I recall it had a flat top with three instead of one vertical drop
wire. One drop wire was in the exact center and the other drop wires
were each side of the center by about, I think, 30%. All were fed
together at the bottom against a gound system.
Herb, if the drop wires are equal distant either side of center, it
would effectively be equivalent to a "fat" vertical element (drop
wire). If you don't mind a little experimentation, try using two wires
separated by 12" with 1/2" PVC pipe every 10 feet or so (like very wide
"open wire" line) for the drop wire. If you have a reasonably tall
vertical element, the 12" spacing should provide decent bandwidth.
How tall is your vertical element?
I saw a multi-wire Marconi similar to what you described on the roof
of the Naval Reserve Armory in the town in which I grew up. However,
one end of the top hat was higher than the other and multiple drop
wires were of different lengths (like a fan). After 40 years, I can't
even remember if the top wire was broken up with insulators making the
antenna multiple parallel inverted "L"s. I suspect it was designed for
very wide band (multiple band) operation back in the cold war days.
73,
... Joe, W4TV
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