Noticed in the 2 element below, I didn't specify which wire was fed.
The 47.7 wire takes the power. The 7.4 wire is reflector only.
----- Original Message -----
From: "Guy Olinger, K2AV" <email@example.com>
To: "Al Williams" <firstname.lastname@example.org>; <email@example.com>
Sent: Wednesday, June 05, 2002 10:36 PM
Subject: Re: [Towertalk] NVIS antenna--reflector addition
> The ground is a reflector, but it is a lossy reflector.
> Best 75 degree numbers I can get for a dipole using earth as
> are around 6 or 7 dbi.
> I'm not sure what figures you were using for an NVIS antenna, but
> this out (7.025 MHz)
> Upper wire = 67.5 feet long, 47.7 feet high
> Lower wire = 68.4 feet long, 7.4 feet high
> I get 11 dbi at 75 degrees with 11.4 dbi straight up.
> The maximum NVIS signal I can get for a single wire = 67.3 feet
> 14.3 feet high. which is just under 8 dbi straight up.
> That's 3 1/2 db extra signal from the reflector, unless you consider
> 3.5 db superfluous.
> And I suspect you didn't have the program which would search out the
> maximum for the single wire NVIS
> The two wire is a very doable 40 meter NVIS antenna.
> 73, Guy.
> ----- Original Message -----
> From: "Al Williams" <firstname.lastname@example.org>
> To: <email@example.com>
> Cc: <firstname.lastname@example.org>
> Sent: Wednesday, June 05, 2002 1:33 PM
> Subject: [Towertalk] NVIS antenna--reflector addition
> > Our club is planning to have an NVIS antenna for 80m
> > and 40 meters during Field Day. However:
> > The World Radio Books publisher's "Near Vertical Incidence
> > Skywave Communication" book purchased from ARRL
> > contains two articles (by the same author) showing an
> > NVIS wire reflector added to the driven NVIS wire element.
> > Because the ground itself is a reflector, and because
> > EZNEC confirms that adding the reflector is superfluos,
> > we do not think a reflector will help.
> > Agree?
> > k7puc
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