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Old July 25th 06, 04:25 PM posted to rec.radio.amateur.antenna
Cecil Moore Cecil Moore is offline
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First recorded activity by RadioBanter: Jul 2006
Posts: 1,614
Default Is It double bazooka less noisy?

Gene Fuller wrote:
Precipitation, at least in the form of rain, often occurs when the
humidity is quite high.


Yes, and triboelectric charging is known to be magnitudes
worse in low humidity conditions. On this web page:

http://www.esda.org/basics/part1.cfm

it says that a worker at a bench can expect 6000v when the
relative humidity is 10-25% Vs 100v when the relative humidity
is 65-90%.

Do you suppose they should have named it dust storm static rather than
precipitation static? Or perhaps dry rain static?


"Charged particle" static would have been more descriptive
since "precipitation" is most associated with falling H2O.

If the relative humidity is 10% when the rain starts falling,
seems the precipitation static would be worse than if the
relative humidity was 90% when the rain started falling.

Dry snow falling in low relative humidity conditions could
certainly carry large charges. Dry wind driven dust particles
in low relative humidity conditions are often associated with
precipitation static.

But assuming that raindrops falling in high humidity conditions
are electrically charged is a questionable assumption. And trying
to detect precipitation static noise in the presence of lightning
seems like looking for a needle in a haystack.

It is good engineering practice to try to isolate what one is
trying to measure. The best way I know of to isolate precipitation
static from other noise sources is to perform the measurements
under clear sky, windy, low humidity conditions in the desert.

I strongly suspect that w8ji didn't detect any of the arcing
noise in the double bazooka that he detected in the bare wire
ungrounded dipoles. Was that a noise reduction?
--
73, Cecil http://www.qsl.net/w5dxp