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Author Topic: Extending whip for improved NVIS operation  (Read 759 times)
W3LK
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Posts: 5644




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« Reply #15 on: July 27, 2007, 04:42:39 PM »

<< There is a ton of info on it all over the internet.>>

With all due respect, not everything "published" on the Internet is credible. Smiley

73,

Lon - W3LK
Naugatuck, Connecticut
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N1LO
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« Reply #16 on: July 31, 2007, 06:17:12 AM »

I have used a low wire, approximately 55-60 feet long, clipped to the *bottom* on my mobile bugcatcher coil. I drape it over bushes and low tree limbs, and fold the end back on itself to achieve resonance. This has worked well for me on the 80m Virginia Fone Net, with good 2-way signals on stations within my state.

--...MARK_N1LO...--
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KE3WD
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Posts: 5694




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« Reply #17 on: July 31, 2007, 09:28:31 PM »

How about when our military itself is published on the internet?

"For mobile or shoot-and-scoot type operations, vehicular-mounted antennas are required. This is the standard 5-meter (161/2-foot) whip bent down to a horizontal position (fig M-9). In this configuration, the whip is essentially an asymmetrical dipole (with the vehicle body forming one side) located close to the Earth. A significant amount of energy is directed upward (fig M-6 for typical pattern) to be reflected back by the ionosphere in an umbrella pattern. For use, while operating on the move, the whip antenna must be tied across or parallel to the vehicle or shelter. This configuration is like an asymmetrical open-wire line, and it also directs some energy upwards although with less efficiency. There are still no skip zones, but received signal levels are weaker than with the whip tied back as shown in figure M-9."

http://www.athensarc.org/fm2418m.asp

Note the direction and method of the mobile vertical tiedown in figure M9 carefully.  


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