In article ,
Irv Finkleman wrote:
Somewhere I recall seeing an article on homebrewing a windowsill
antenna similar to the B&W AP-10. Does anyone have a copy they
could email me, or a link where I can find the information. I was
hospitalized for serious problems and all my ham gear including many
books were donated to the local ham club -- I'm starting again from
scratch after 54 years of hamming, but on a much smaller scale!
I don't know of a specific article, but
http://www.bwantennas.com/instr/Ap10b.pdf
is the instruction sheet for the final version of the antenna. Page 2
shows a fairly decent physical diagram of the antenna coil
construction.
Basically, the antenna appears to be a telescoping whip, with a large
air-core inductor / loading coil mounted below it. A flying lead is
used to short out some of the turns on the coil, in order to set the
amount of inductance. A variable-length counterpoise wire is used;
both the counterpoise length and the loading-coil fly lead setting
must be adjusted for each band in order to get a good match.
You could probably either use a piece of Airdux inductor stock, if you
can find one at a hamfest / flea market, or wind your own inductor on
some sort of suitable form (perhaps PVC pipe?).
It looks like a fairly standard "small antenna" approach.
Addition of a small LC tuner at the base (homebrew, variable cap +
recycled roller inductor?) might save you some time during setup and
band changes, by reducing the need to fiddle with the counterpoise
length and position to get a usable impedance match.
--
Dave Platt AE6EO
Friends of Jade Warrior home page:
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