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

Art, KB9MZ wrote:
"Thus this is inferior to a vertical that captures the low angles and
discriminates against the high angles plus inferior to a poor vertical
that discriminates against low angles."

Yes, a vertical discriminates against high angles as it has a null in
its pattern overhead.
What "poor vertical" discriminates against low angles if ground
conductivity is OK? A too-short vertical still has maximum radiation
toward the horizon though it has less than a 1/4-wave or 5/8-wave
vertical antenna has.

Best regards, Richard Harrison, KB5WZI

Mark Keith wrote:
"My dipole on 40m was only 35-40 ft. Not 1/2-wave up. But not once did
it ever beat my vertical long haul."

I believe Mark. The scales may be tilted in the favor of Mark`s vertical
by the high-conductivity soil at Mark`s QTH.

Commercial stations spend what it takes to put those horizontal antennas
up at elevations which bring the take-off angle down low enough to reach
out the distance to the target area.

At high elevation, a dipole becomes bidirectional in azimuth. This gain
is often enhanced by a reflector, directors, extended element lengths,
or additional in-phase elements. Curtain arrays are popular transmitting
antennas. So are rhombics, especially for point-to-point, for both
transmission and reception.

Receiving antenna farms rely on rhombics, Beverages, fishbones, etc,
where the object is directivity and gain to give S/N, if not efficiency.

Best regards, Richard Harrison, KB5WZI

(Richard Harrison) wrote in message

Receiving antenna farms rely on rhombics, Beverages, fishbones, etc,
where the object is directivity and gain to give S/N, if not efficiency.

Best regards, Richard Harrison, KB5WZI

I was thinking earlier that it should be easier to build high gain
arrays for low freq's horizontally, than vertical. Easier to go out
parallel to the earth, than to build a load of tall towers to act as
an array. But if they use tall towers to support a rhombic of
whatever, I guess it might even out. MK