Dear Tom:
Your message may one of the most interesting and unexpected that I have
read in a long time. Some comments follow. Please note my extreme
reluctance to engage in anything but a calm exchange of experiences and
opinions. I have no interest in provoking you.

Your experience does not seem to agree with experience at remote, flat,
treeless sites here in Michigan. Please note the qualifiers in the last
sentence. Especially in the UP of Michigan, at certain times of the year,
P-noise is the major factor in limiting radio use.

P-noise is not found on an antenna imbedded in a clump of trees when an
antenna out in the open (many wavelengths from the first antenna) has
P-noise. The follow-on is that since most sites are urban or suburban, few
radio amateurs will experience P-noise.

P-noise is observed when there is no rain nor thunderstorms, but plenty
of wind. This is suggestive of moving charge discharging into the antenna.
Of course, one could define this action as being "corona." Of course, if
one places enough charge on a piece of metal eventually there will be
"corona." Many antennas have a conductive path to earth that makes such an
accumulation of charge unlikely.

There is no doubt that an antenna experiencing P-noise will radiate and
thus noise will be received by nearby antennas. That is why successful
receiving antennas here in the flatland are placed a long distance from
metallic objects.

Most people have never heard P-noise because their site precludes same.

A paper published in August about 1961 (IEEE Vehicular Transactions) is
one of the few references that has been published that deals with means for
reducing P-noise. The article involved a fixed, not mobile, antenna. It
appears that additional work has not been published that deals significantly
with fixed antennas. (Lots of papers exist dealing with aircraft antennas.)

Your #6 is interesting. Unfortunately, there is so much radiation from
what else is on a tall building that it is difficult to sort out where
excess noise is coming from. An antenna inside of a slightly conductive
radome that is placed a long distance from anything that could radiate might
be different.

Your #7 is especially interesting. Our EMC group has on the drawing
board just such experimentation. We will be on the lookout for "end
effects." Your note is a valuable observation.

Regards, Mac N8TT

--
J. Mc Laughlin; Michigan U.S.A.
Home:
wrote in message
ups.com...

Reg Edwards wrote:
Precipitation static, eg., from highly charged raindrops and fine snow
or fine sand, impinging on the antenna wire, just causes an increase
in receiver white noise level. It can be reduced but not removed by
using a very thickly insulated antenna wire, like the inner conductor
of a coaxial cable complete with its polyethylene jacket.
----
Reg.

I've never seen a case of precitation static occuring that way.

In every single case I've seen, whether on tall buildings, tall towers,
or antenna hear earth, it has always been corona discharges from the
antenna or objects near the antenna.

How do I know this?

1.) I had side by side "insulated" and "unisulated" Beverage antenna
wires that are otherwide identical except for being spaced a few dozen
feet apart, and the antebnna pointed towards my tall towers had precip
static and the others did not. Both were equal in noise despite the
fact they are hit by the same rain or dust.

2.) I have Yagis on towers that are identical, and the LOWER antenna
almost never has precipitation static despite the fact they are hit by
the same rain or dust.

3.) I've had dipoles at various heights, and the lower dipole always
has much less precipitation staic than the high dipole despite the fact
they get the same rain or dust.

4.) The period of the noise has nothing at all to do with the number of
droplets hitting the antenna. It increases in pitch as the charge
gradient between earth and clouds builds, then when lightning flashes
it immediatly stops without time delay.

5.) On tall buildings on dark nights in storms, we could actually hear
the same pitch noise as the repeaters rebroadcast, and walk to the
noise source and actually see the corona.

6.) Antennas in fiberglass radomes were no quieter than bare metal
dipoles on tall buildings.

7.) I even used an electrostatic sprayer to charge droplets and hit an
antenna, and could only simulate noise when the antenna element had a
sharp point and I got near the sharp point...at which time I could see
faint corona.

73 Tom