W8JI said:
With narrow lobe antennas that cannot be rotated, we have to
plan the location of nulls or lobes or play roulette. The
signal might fall in a 20 dB hole just as likely as on a 6dB
peak.
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It certainly is true that usage of "fixed direction gain pattern antennas"
requires some pre-planning.
Working in the government as an HF engineer gave me the opportunity to
design and use
many rhombic antennas. They can be very effective, if you understand the
propagation to the target area,
by providing a broadband antenna targeted on a specific area. I think loops
can be another tool to
provide good antenna coverage to particular areas if you have the required
resources. In my case I
have the trees at good height and spacing. 250' of copper is pretty cheap,
as is the rope to raise the wire.
Changing the feed-point corner changes the main lobe direction. Due to the
directions of central Europe and
Southeast Asia, with respect to my trees, I get good lobe coverage on much
of those areas. The neighbors can't
see the wire and the antenna is very low cost and provides good gain/target
coverage. While the loop may not work
well as the only antenna, it can provide good performance for specific
areas of the world.
Merle Bone - W0EWM
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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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