Cecil Moore wrote:
wrote:
J. Mc Laughlin wrote:
Moving dust particles can carry charge and become charged. The noise does
follow the "pattern of the particle rate."
I've never seen it do that. But I'll keep watching for it.
In Arizona, the harder the wind blew on a clear day, the shorter the
length of time between arcs on my coax connector. In a high wind, it
sounded something like the rat-a-tat of a machine gun.
Let's see if I can explain this in 200 words or less. :-)
One popular supposition is what Reg indictated, that P-static is caused
by charged droplets hitting the antenna. As each little drop hits the
antenna, it makes a noise from the transfer of charges.
I always thought that also until I started working on antenna systems
on tall towers and buildings. Trying to make them not "noise up" when
the weather was bad turned out to be impossible when the antenna was
near the top of a structure. Shielding the antennas from moisture with
insulation didn't help. The only thing I found that helped was making
another object the tallest sharpest point on the structure, or
insulating or "rounding" the ends.
One of the things I did with a fiberglass Super StationMaster was to
drop a large plastic bucket over the sharp lightning spike at the top,
and the noise all virtually vanished.
Another was placing a copper toilet tank float ball on the top to make
it smooth and round. Worked almost as well as the bucket. So did
putting up a taller mast on a roof away from the VHF or UHF antenna. On
one bank roof with a radio staion's remote brodcast pickup antenna and
two way radio antenna, we just installed a metal flagpole about 50 feet
away (they wouldn't let us have a pipe that protruded above the
roofline as seen from the street, but they accepted and used the
flagpole).
I started listening to my antennas at home, and noticed the same thing.
Lower antennas were always much more immune to what people call
P-static.
Now I'm not saying wind, dust, and moisture blowing across a
well-insulated antenna won't charge it faster, and make an antenna
without a ground path leak arc over some close gap more rapidly.
I'm only saying I never have seen the noise pitch of what people
commonly call P-static track the actual number of droplets or dust
hitting the antenna, and everything else I've seen indicates the rapid
popping that turns to a sizzle and then an almost musical pitch seems
to be tied only to charge gradient between the antenna and the
surrounding air.
I've been on the top of very tall well-grounded BC towers on days with
a stiff stready wind, no dust or rain, and seen a sharp bracket or
sharp strand of guyline poking out hissing with corona streamers.
That noise sounds just like what everyone I know calls "P-static".
73 Tom