The easiest way to get high quality multiband
perforance from half wave verticals is to put up
several single band half wave verticals, each with its
own tuning network, over the same ground field. Use a
remote coax switch to band switch between tuners.
Parallel networks are cheap and easy to build. I
build mine out of #6 copper wire from Lowes wound to
3" diameter, mounted with its capacitor to a piece of
sheet aluminum bent into a shallow U. I use a plastic
shoe box from the dollar store to enclose the network.
I had a few surplus caps on hand and built 4 of them
for under $20.
I presently have half waves wire verticals up on 40
and 30 and a 5/8 wave on 20, which coexist with a 160M
wire inv-L and a 80M full size 1/4 wave all over the
same radial field. The antennas show essentially no
interaction between each other, and each can be peaked
up for best performance or experimentation without
worry about lousing up the performance of any of the
others.
I did A/B comparisons on many bands against a
multiband Butternut and a 138 ft flattop at 60ft, and
found these antennas were superior by several DB
(usually 1 to 5) on paths greater than 4000 miles.
They are cheap and easy to build and easy to make
work. They might be a good addition to anybody's
antenna farm.
73 W9OY
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