One of the best technical presentations on NVIS propagation and antennas is
at:
http://groups.yahoo.com/group/wl2kemcomm
Look in the files section for NVIS_Presentation_R1-4-8a.pdf by WA5BEN. You
need to join the group to access the files section. There are older
versions of the file at other sites, but get the latest rev.
Optimum height is 1/8th wave (30' for 80M, 16' for 40M). Anything less just
reduces efficiency with excessive ground losses.
I use a 80/40 fan dipole at 20'. 80M needs a tuner to cover the band, but
40M covers 7.1 - 7.3 at less than 1.8:1 SWR without a tuner. 7.1 MHz is as
low as I need to go for Winlink Pactor -- don't do CW. I have an identical
antenna in my go kit for portable use.
Steve, W3AHL
----- Original Message -----
From: "Tom Osborne" <w7why@verizon.net>
To: "Towertalk" <towertalk@contesting.com>
Sent: Monday, August 24, 2009 10:22 PM
Subject: [TowerTalk] Folded dipole
> Hi All
>
> Looking to put up another 40 meter antenna. Need a NVIS antenna for
> close-in work.
>
> Is there any reason to put up a folded dipole instead of a tuned-feeder
> dipole?
>
> I think when this antenna was popular, it was touted to have more
> bandwidth
> than a dipole. But, if you have to use an antenna tuner to tune it
> anyway,
> there doesn't seem to be any advantage over a regular antenna, bandwidth
> wise. 73
> Tom W7WHY
>
> _______________________________________________
>
>
>
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