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Old June 7th 06, 11:10 AM posted to rec.radio.amateur.antenna
 
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Default H FIELD ANTENNAS?


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