[Milsurplus] PRC-74

[Gene Smar]

Jeff:

     Here's a URL http://www.radiowavz.com/html/nvis.htm that discusses NVIS (Near-Vertical Incidence Skywave) antennas.  You can also search on NVIS and find numerous other sources.  Theses antennas are essentially low-to-the-ground horizontal dipoles that exhibit high take-off angles for low-band HF signals.  The high T.O. angles of NVIS antennas permits signals of up about 12 MHz to be returned to earth within 300-500 miles of the transmitter (between ground wave and first e-layer skip range) with very little attenuation.

     One military antenna model designed specifically for NVIS work is the AS-2259.  This is two crossed dipole inverted V wire sets, resonant at about 6.5 MHz and 9.0 MHz, that are supported by sections of fifty-Ohm rigid transmission line.  You would need a tuner between this antenna and your -74.  I, and others on this reflector, have made similar antennas, but the wires are resonant on 80M and 40M (or 60/40 or 80/60, etc.)  Coverage from my antenna on the low bands (80 and 40) is excellent, with highly readable signals out to several hundred miles with 80 Watts from my own batt operated IC-746.

     Scroll down on the above URL to M-7. There are results from tests done by the US Army in Thailand's jungles with PRC-74's.  If you team up your own -74 with one of these NVIS wire sets, you WILL be heard out to several hundred miles.


73 de
Gene Smar  AD3F


 From: n2lxm at juno.com
Date: 2008/06/13 Fri PM 03:50:02 EDT
To: milsurplus at mailman.qth.net
Subject: [Milsurplus] PRC-74

Greetings All,
 
        Well after all most a year of collecting bits and pieces I am all
most ready to get my PRC-74 on the air. I am looking for information and
suggestions on what would be a good antenna to use for portable work.
Also having just received an CY-6121( wet ) battery box, I have been
looking for specifications for the BB-418/U battery. From my research
using the radio with a 9 to 1 RX / TX ratio would require a 12 -15 volt
battery with a 15Ah rating. Can anyone confirm this as fact.  I am hoping
to be ready for Field Day and to have some fun this summer going back
packing. Any input will be greatly appreciated. Thank You.
 
 
                                Jeff N2LXM
                  AMATEUR RADIO OPERATOR
                                AMERICAN
                                  PATRIOT
                  Proud Father of two US MARINES
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