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Old April 11th 07, 03:18 PM posted to rec.radio.amateur.antenna
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Default NVIS Dipoles Directional?


"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?

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.

Yuri, K3BU.us


 
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