A good source of reprints on NVIS antennas is "Near Vertical Incidence
Skywave Communication: Theory, Techniques and Validation" by Fiedler and
Farmer. It's available from Worldradio Books, P.O. Box 189490, Sacramento,
CA 95818. Cost me $14 plus a coupla bucks P&H.
Authors are retired Army Signal Corps and current Calif National Guard,
respectively. Their book tells of military and Guard experiments in NVIS
operations. They advocate NVIS antennas for close-in communications on HF
(out to 200-500 miles or so from transmitter.) Just the thing for emergency
and
other public service amateur operations. Floods and tornadoes wreak
widespread havoc with local power grids and antenna installations, leaving
repeater-based networks handicapped. With NVIS-equipped stations, there is
a reliable alternative to linked-repeater networks. HF fixed/portable
stations can handle PACTOR messages and other admin traffic, leaving V/UHF
mobile stations to handle tactical and damage-assessment roles.
NVIS also can operate effectively in mobile environment. (See the book's
last section on tests run by military, Guard and FEMA operators.) All such
installations need a tuner at the antenna feedpoint, as W6CJ correctly
points out.
I'm using a NVIS antenna of sorts: full-wave horizontal loop on 80 M. I
feed it with 450 ohm twin lead through a balun and tuner and can load it on
all ham bands, including WARC. On 80 and 40 I'm told the signal is usually
S-9 up and down the east coast. (Running 200 Watts.) Based on my
experience with it, I'll always recommend this kind of NVIS antenna.
Hope this helps.
-Gene Smar AD3F
-----Original Message-----
From: Jepilot@aol.com <Jepilot@aol.com>
To: towertalk@contesting.com <towertalk@contesting.com>
To: <towertalk@contesting.com>
Date: Thursday, November 19, 1998 11:45 AM
Subject: [TowerTalk] Fwd: [Antennas] cloud warmer
>
>
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