In message ,
writes
Ian Jackson wrote:
In message ,
writes
Ian Jackson wrote:

snip

Despite the obvious theory, and over 50 years in amateur radio, I still
find it hard to believe that, in real life, an 80m dipole at (say) 20'
ever really outperforms (at any distance) one at (say) 100'. Given the
choice, I know which one I would choose!

Try reading these:

http://www.qsl.net/wb5ude/nvis/
http://en.wikipedia.org/wiki/Near_ve...idence_skywave
http://www.w0ipl.net/ECom/NVIS/nvis.htm
http://kv5r.com/ham-radio/nvis-antennas/
http://www.arrl.org/nvis

Thanks, I'll certainly have a good read of those articles. But
regardless of what they say, in a typical amateur scenario, I still
reckon that at (say) 300 miles, an 80m signal from a dipole at 100' is
likely to be stronger than one from one at 20' (or even at 60').

As 300 miles is at the upper end of NVIS and the lower end for skywave

NVIS IS skywave - only that it's more straight up-and-down than at an
angle. It's only a matter (literally) of degree, and there's no real
point at which NVIS becomes 'normal' skywave.
,
it would be a crap shoot.

NVIS distance is typically 30-400 miles.

OK, let's make it a bit less - say 50 or 100 miles. I still feel that,
in practice, a dipole at 100' would be unlikely to be less effective
than at 20'.

On the other hand, if you only want to lay down a signal out to less
than 400 miles, there's no point in going to the trouble of putting the
dipole at 100'. Apart from cost etc, this would also unnecessarily cause
QRM to reception outside your intended target area.


--
Ian