Horizontal Attic Loop Feed
"Wayne" wrote in message
news:4EBii.3183$fw2.1666@trnddc04...
Looks like I'll have to use a horizontal loop in the attic for a few
months.
Any opinions on how to best feed it?
--open wire
--coax coil balun
--ferrite bead balun
--straight coax
The loop is about 13 feet per side, and I want to operate 20 meters and
up.
In the past I have simply used a coax feed without a balun. It worked OK,
but there was a lot of stray RF around the house.
TIA
Wayne
Personally I would try feeding the loop with open wires from the balun
output of an ATU. You don't state what sort of power you want to use, but I
would think that this method would be okay up to a miximum of 100W. It
depends on how much wiring you have running parallel to sections of the
antenna up in the attic.
If you must use coax, winding as many turns of coax as possible on an old
6-8 inch ferrite rod just before the loop will keep most of the RF off the
outer shield of the coax.
Winding coax around ferrite rods or large toroids is usually much easier and
more efficient than using loads of ferrite beads as a balun.
Straight coax is okay for powers less than 20W but a few turns around a bit
of ferrite would still be advisable.
Mike G0ULI
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