Inverted vee dipoles do produce some vertically polarized radiation off the
ends. However, that vertical component has maximum gain at zenith, i.e.
straight overhead. It does not contribute to any significant low-angle
radiation. You can see this by doing an antenna model.
73, John W1FV
-----Original Message-----
From: Topband
[mailto:topband-bounces+john.kaufmann=verizon.net@contesting.com] On Behalf
Of Jim Brown
Sent: Sunday, March 15, 2020 2:36 PM
To: topband@contesting.com
Subject: Re: Topband: NVIS Antenna
Hi Ed,
I've studied this extensively for horizontally polarized antennas, but
only for flat ones; I thin that inverted Vees have some vertical
components.
For horizontally polarized antennas, maximum gain at high angles occurs
at a mounting height of about 75 electrical degrees, and falls by only
about 1 dB if raised to 120 electrical degrees. By "high," I'm talking
70 degrees elevation.
Also, RX is different from TX, in that with RX we don't care about loss,
only signal to noise. Ground loss is a contributor to those variations
based on mounting height. N6RO, an old hand on topband with a great
antenna farm, rearranges his M/6 station for topband contests to bring
LOTS of his antennas to the station he uses single-op.
That study is here. http://k9yc.com/AntennaPlanning.pdf
73, Jim K9YC
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