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On Tue, 06 Jan 2004 06:11:17 GMT, (Larry W4CSC) wrote:

On Mon, 05 Jan 2004 02:02:17 GMT, Gary Schafer
wrote:

All antennas are two terminal devices.
There is no such thing as a single point feed antenna.

Changing a horizontal antenna to a vertical antenna at the same height
does not improve the radiation angle.
If it did everyone would have their horizontal antennas in the
vertical position.

AM radio stations depend on ground wave signals not sky wave.

A horizontal antenna theoretically does not have a ground wave so
verticals are used for AM stations as they produce a ground wave
signal.

Hmm....I've been using horizontal antennas to transmit ground wave
communications since I was 11 years old in 1957!

All VHF and UHF TV stations use ground wave only signals and every one
of them in the USA are HORIZONTALLY POLARIZED. Kinda blows that
theory all to hell, doesn't it? Until very recently, all FM radio
stations were all horizontally polarized, too, but that was changed
because cars have vertically polarized antennas......or did when they
changed the rules. Embedded FM antennas in windshields are
horizontally polarized, a dipole.

For sky wave signals height is important in order to produce better
lower angle of radiation. Lower angle radiation provides longer hops.

Depends on how far you wish to talk. I use very high angles of
radiation on 3915 Khz to talk to my buddies around SC, NC and Georgia
on 75 meters. This is easily possible because my inverted-V dipole is
only up about 30', not much % of a wavelength when the wavelength is
240 feet long. Listen from 3.5 to 4.0 Mhz nights and 7.0-7.3 Mhz days
and hear lots of us "high-angle-radiators" shooting the breeze, ad
nauseum. Works great since 1957....(c;

Adjusting the height to adjust the impedance of the antenna is not to
be worried about. That's what matching systems are for.
With multielement antennas (beams) the feed point impedance can be
very low even if the antenna is high in the air. Some other means of
matching the antenna to the line is required.

Absolutely nothing radiates like a TUNED antenna, without the lossy
tuner between feedline and antenna. Damned Navy has tuners so
inefficient trying to load a flagpole whip they have to have BLOWERS
in them to keep from melting them. All that power ISN'T radiated,
obviously.

TV and FM stations do not depend on ground wave propagation. It is
line of sight. Nothing to do with polarization or ground wave.

FM stations have had dual polarization (both horizontal and vertical)
for many years. Only because cross polarization with the receiving
antenna greatly attenuates the signal.

Ground wave propagation as in AM stations is not a sky wave. It
follows the curvature of the earth staying close to the ground (ground
wave).

A horizontal antenna does not produce any significant ground wave.
(wave that stays close to the earth) The ground wave from a horizontal
antenna will fall off in just a few miles.

Yup that's what I said. "For sky wave signals height is important in
order to produce better lower angle of radiation. Lower angle
radiation provides longer hops."

The propagation that you experience on 80 and 40 meters with the guys
around the state is the result of high angle radiation and reflections
as you state.

If you want higher angle, shorter hops, keep the antenna low.

Tuned antenna? I assume you are referring to a "resonant antenna"?

A non resonant antenna radiates just as well as a resonant antenna.
Only difference is the impedance presented to the feed line. But even
a resonant antenna may not provide 50 ohms to your coax. Depends on
how high it is. :)

Regards
Gary