"Yuri Blanarovich" wrote in
:


"Dave Oldridge" wrote in message
9...
Rick wrote in
news
On Mon, 09 Apr 2007 23:36:56 +0000, Dave Oldridge wrote:

NVIS propagation is pretty high angle stuff. If you look at the
three dimensional patterns for NVIS antennas you will see that they
have a large lobe at high angles and an almost circular
omnidirectional pattern at those angles. We're looking at 80
degrees and up mostly here, maybe 70 at the low end....so that
antennas are mainly designed to illuminate the patch of ionosphere
directly above the antenna.

Right. That's my point. So, what I'm claiming ... and trying to
get someone who knows more about this stuff than I do (which is just
about all of you) to confirm or deny ... is that with an NVIS
dipole, someone 100 miles away from me would not be able to perceive
the difference if my antenna was broadside to him or oriented in
line with him. True, or false?

Absolutely true. Any difference would be insignificant. The path
elevation is about 79 degrees for that path.

--
Dave Oldridge+
ICQ 1800667

Absolutely???

So if you suspended another dipole above your NVIS dipole and oriented
90 degrees to each other, the difference would be insignificant?
Then move it up into the "clouds", then move down to earth at the
distance and you will see "insignificant" difference in signal levels?

Seems that direction finders should not work according to this
"verdict", Eh?

And they don't actually work on NVIS signals unless you use them to
measure elevation, in which case they point fairly high up.

One thing is the direction of the signals (maximum) another one is the
polarization. Based on the orientation of antennas, one can orient the
antenna to find the minimum signal.

You're assuming the ionosphere doesn't rotate the signal (or even render
its polarization elliptical). Whether that's happening or not will
likely depend on conditions at the time. But if it doesn't, then it
doesn't matter which way the antennas are oriented in azimuth so long as
they are both oriented the same.

--
Dave Oldridge+
ICQ 1800667