[TowerTalk] NVIS antennas Re: dumbing down

[Tom Rauch]

> At 02:00 AM 7/22/2005, Tom Rauch wrote:
>
> >At 1/8th to 1/4 wl high NVIS signal is maximized. Anyone
who
> >spent any time at all with antennas would know even with
a
> >perfect reflector efficiency drops rapidly when the
antenna
> >is spaced less than 1/10th wl from a reflector, and if
the
> >reflector (earth) was lossy things would go in the toilet
> >fast as height was reduced.
>
>
> Might well be, though, that a 18" or 2' high wire is much
easier to deploy
> in a field situation, than trying to get a wire up 1/4
wavelength on 40 or
> 80?  From a system standpoint, you might be willing to
accept the lower
> efficiency (and the certain interactions with objects
likely to be near it)
> in exchange for a faster deploy.

If that is the advantage he had in mind, the writer would
have said that Jim. He plainly gets into nonsense about
groundwave/NVIS phase errors.

I don't think 18 inches high is a safe NVIS antenna height
for field deployment and it certainly is not electrically
worth a hoot. 18 feet, yes. 18 inches, no.