I have had great luck with a set of vertical dipoles
for 10-20. I use them as back-up second radio transmit
antennas, but they work wonderfully as receive antennas
too.
I would build vertical dipoles, rather than 1/4 wave
verticals, for 10, 15 and 20. For 10 and 15, full
size is easy, and will be free-standing in your
configuration. I mounted mine to the posts of a
pasture fence at N6NF (one antenna per post, one
every other post) and they worked wonderfully.
For 20 meters, I use a 6' top-hat (one piece of
6' aluminum rod, slid through a hole in the
element and welded in place) and a 6' bottom hat
(two 3' pieces of copper wire attached to a self-
tapping screw). This makes the 20 meter antenna
about the same height as the 15 meter one, just
for mechanical ease.
Vertical dipoles don't need radials, and are
ground independent - which IMHO makes them
much easier to deal with.
I use 75 ohm matching sections and 50 ohm feedline
for mine.
I would suggest that you build them to be
resonant. There really isn't any reason not to,
tuning them is a snap, and you might want to
transmit into them in an emergency...
GL es 73,
***dan, K6IF
See you all in the California QSO Party,
October 4-5!
_______________________________________________
See: http://www.mscomputer.com for "Self Supporting Towers", "Wireless Weather
Stations", and lot's more. Call Toll Free, 1-800-333-9041 with any questions
and ask for Sherman, W2FLA.
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