On Sun, 2 Jul 2006 18:43:35 -0000, "Dave" wrote:

you don't want to think 'loading coils' you want to think 'traps'. they are
two very different animals. loading coils are simply inductors that make
the wire look longer electrically so you don't need as much room. traps are
resonant circuits that exhibit a very large impedance at their tuned
frequency so that it cuts off part of the antenna. usually you use a trap
for multi-band dipoles, the first trap out from the center is tuned to cut
off the outside of the element at the highest frequency, and then at lower
frequencies it looks more like a small inductor so helps a bit as a loading
coil on the lower band.



Actually, if you check the ARRL antenna handbook or the annual
handbook, or maybe even the web site, they have a dual band 80/40
meter dipole that uses loading coils instead of traps. One version
uses a drop wire at the end of the 40 meter band to trim without
moving the coils or adjusting the 80 meter frequency.

I haven't tried it, but I have seen other antennas designed on it's
principal, mainly vertical 1/4 wave antennas, but they worked so I see
no reason the dipole shouldn't.

Will the fan-dual-band dipole work? I suspect so. However, I highly
suspect that the parallel dipole (a fan with the elements 6-8 inches
below each other) will work better.

Good luck
Buck

--
73 for now
Buck
N4PGW