Yuri, K3BU wrote:
"Recent studies found efficiency of various polarizations based on
geographical location, related to geomagnetic fields (gyrofrequency).

Do antenna modelimg programs adjust for gyrofrequencies? I can readily
see that soil conductivity at a geographical location would affect
efficiency and perhaps the polarization choice.

John H. Nelson, RCA Short-Wave Radio Propagation Analyst, found that
those signals which pass through or close to the auroral zone suffer the
greatest degradation. If the signal must take a great circle route over
the North Polar region, problems increase.

Nelson also found that propagation here on the earth correlated with the
relative positions of the planets in the solar system. Be this astronomy
or astrology, it allowed Nelson to make pretty good radio propagation
forecasts. See: "The Propagation Wizard`s Handbook", a "73" publication
by J.H. Nelson.

Best regards, Richard Harrison, KB5WZI

On Sat, 3 Jan 2004 10:35:51 -0600 (CST),
(Richard Harrison) wrote:

If the signal must take a great circle route over
the North Polar region, problems increase.

Hi Richard,

This is a S+N/N problem, not propagation. It is not like the magnetic
pole is sucking signals into the ground. What the pole IS attracting
is the ionic flow from the sun's emissions which create a plasma of
noise.

73's
Richard Clark, KB7QHC

This is a S+N/N problem, not propagation. It is not like the magnetic
pole is sucking signals into the ground. What the pole IS attracting
is the ionic flow from the sun's emissions which create a plasma of
noise.

73's
Richard Clark, KB7QHC



On 160 and 80 during disturbed conditions (aurora, etc.) signals are skewed by
as much as 90 deg from their short path directions. So it is not sucking but
blowing signals away from the disturbed region. Maybe sucking too, I haven't
been up there to see it. It is not just noise problem.
Some outrageous propagation stuff is in my old article at
http://members.aol.com/ve3bmv/bmvpropagation.htm

Yuri, K3BU, VE3BMV

When both antennas have about the same height at their centres -


A half-wave vertical is better at low elevation angles.


A half-wave horizontal dipole is better at high elevation angles.


There's nothing at all to choose between them at 45 degrees.


For each of the following factors allow a predicting uncertainty of +/- 1/2
S-unit -


MF, HF, sun-spot cycle numbers, day, night, summer, winter, aurora, N/S,
E/W, giro-magnetic disturbances, high-rise city centers, arid deserts, the
oceans, mountain ranges, prairies, pampas, steppes, tropics, arctic
regions, G5RV's and unsociable noisy neighbours.


Use RMS summation of predicting uncertainties.


If you are using Roy's S-meter calibration multiply by 2. ;o)


And that just about sums it up.
----
Reg, G4FGQ

--
.................................................. ..........
Regards from Reg, G4FGQ
For Free Radio Design Software go to
http://www.btinternet.com/~g4fgq.regp
.................................................. ..........
"Richard Clark" wrote in message
...
On Sat, 3 Jan 2004 10:35:51 -0600 (CST),
(Richard Harrison) wrote:

If the signal must take a great circle route over
the North Polar region, problems increase.

Hi Richard,

This is a S+N/N problem, not propagation. It is not like the magnetic
pole is sucking signals into the ground. What the pole IS attracting
is the ionic flow from the sun's emissions which create a plasma of
noise.

73's
Richard Clark, KB7QHC