Topband: NVIS Antenna

[Jim Brown]

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 at 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.