Topband
[Top] [All Lists]

Re: Topband: NVIS Antenna

To: topband@contesting.com
Subject: Re: Topband: NVIS Antenna
From: Jim Brown <jim@audiosystemsgroup.com>
Reply-to: jim@audiosystemsgroup.com
Date: Sun, 15 Mar 2020 11:35:53 -0700
List-post: <mailto:topband@contesting.com>
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

On 3/15/2020 9:28 AM, sawyered@earthlink.net wrote:
I put up a 160M full size inverted vee.  Top at about 55ft and ends at
around 15 feet.  Just high enough to decouple some of the ground losses but
other than that, straight up radiation for the most part.

_________________
Searchable Archives: http://www.contesting.com/_topband - Topband Reflector

<Prev in Thread] Current Thread [Next in Thread>