[TowerTalk] reflector for 75 meter inverted vee
ersmar at comcast.net
ersmar at comcast.net
Wed Oct 4 16:07:26 EDT 2006
Jerry et al:
Such antennas (low to ground, high angle radiators on bands up to around 10 MHz) are more commonly know as NVIS antennas (Near Vertical Incidence Skywave.) There are quite a few references to such on the web. (See http://www.co.missoula.mt.us/acs/antennas/NVIS%20EZNEC.htm and http://www.w0ipl.net/ECom/NVIS/nvis.htm - scroll down to N7NVP and W6QJI in What Works Well?)
Their use in Ham Radio circles (and military, for that matter), is for improved <skip-zone> coverage, i.e., that area around a transmitter where ground wave fades out and before the first E- or F-layer bounce on the ground occurs. Most literature that I've read on the subject considers this distance from 50 to 500 or so miles out.
Hams would use such antennas for domestic contesting, i.e., SS or Field Day, or for EmComm activities where local infrastructure has been damaged and receive points are beyond V/UHF range from the disaster sites.
73 de
Gene Smar AD3F
>
> It is possible to build arrays that squirt the signal straight up with
> significant gain, but the beamwidth is fairly narrow, and these antennas
> don't seem to have any applications in ham radio.
>
> Jerry, K4SAV
>
> Joe Barnes wrote:
>
> >I am considering putting up a wire about 1/4 wave below my 75 meter
> >inverted vee that is 10 percent longer than the inverted vee to use it
> >as a reflector for closer in ( within 700 miles or so) communications.
> >Does anyone have any experience with such a thing? The inverted vee is
> >at 95 feet at its apex. Thank you, joe barnes N4JBK
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