Raymond Albers wrote:
I have mounted an ATU in the attic and attached a 1:1 balun directly
to it, with about 25 ft of wire going out from each side - in other
words, a non-resonant dipole - all inside the attic. It loads OK on
all bands 80 thru 10 and I've made several decent contacts with it.
This antenna will work better without the balun in this position. The
impedance of the antenna varies all over the map and the balun will be
ineffective on some bands, and lossy on others. It will probably be
helpful on 30 meters!
I am contemplating using the ridge vent as part of the antenna: I
could position the ATU at one end of the attic, connect one side to
the ridge vent and the other side to a stealth wire that I could run
to a low tree or maybe the peak of the garage roof.
As someone else pointed out, you will have to ensure continuity between
the various pieces that make up the vent. On bands where voltage loops
appear on the vent, wet weather will seriously detune it and increase
losses. Ron's suggestion of making a doublet with part outside and part
inside the attic seems to me the best choice. No. 22 or 24 enamelled
wire is probably small enough to be invisible at a distance. Do not use
a balun at the feedpoint, however.
--
73,
Vic, K2VCO
Fresno CA
http://www.qsl.net/k2vco
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