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Dave Oldridge · January 25th 07, 03:20 AM posted to rec.radio.amateur.antenna

Mike Coslo wrote in
36:

wrote in
ups.com:

Hi Mike, I built one similar to this myself. I always assumed the
spiral wound lower section added some distributed inductance that
would reduce the amount needed for the upper loading coil. The
inductance added by the spiral section could be modeled by adding a
couple of inductive loads on the lower section. The effect of the
loads will be to change the current distribution slightly on the
lower section of the antenna. The spiral bottom does radiate.

Sounds sensible. Is there any future in trying to get this thing to
work on 40 meters?

This is actually not that different from the commercial "hamstick" mobile
antennas. I have a set of them on my balcony that I use. 40m is very
noisy here, but I can regularly be heard down the coast in Oregon and
California and have worked Japan in the wee small hours (from just east
of Vancouver, BC).

They're not very efficient on 80, a bit better on 40, and OK on 30, 20,
15 and 10 (those are the bands I have antennas for).

--
Dave Oldridge+
ICQ 1800667