wrote:
All through this my IAC double bazooka was no quieter than a regular
dipole made from #16 bare copper located 100 feet away at the same
height.

This test was with all antennas in place at the same time on the same
day in the same weather.

Precipitation static doesn't always occur during thunderstorms.
It's effects are greatly reduced in high humidity environments.
For precipitation static to occur requires charged particles.
And you don't know if charged particles even existed during
your experiment. To separate charged particle effects from
lightning effects you need to run your experiment without
the clouds and thunderstorms under conditions that guarantee
charged particles. That would be during a dust storm on a clear
sky day under low humidity conditions as often exist in Queen
Creek, AZ.

Precipitation static is a large problem for airplanes but
only when they are flying through a field of charged particles.
One of the treatments for precipitation static on airplane
antennas is to insulate the antenna inside a non-conductive
pipe. Another treatment is to fold the antenna. These are
well known, well accepted methods of reducing precipitation
static problems on airplane antennas. You can verify those
facts for yourself through a little web research.
--
73, Cecil http://www.qsl.net/w5dxp

Cecil Moore wrote:


Precipitation static doesn't always occur during thunderstorms.
It's effects are greatly reduced in high humidity environments.
For precipitation static to occur requires charged particles.
And you don't know if charged particles even existed during
your experiment. To separate charged particle effects from
lightning effects you need to run your experiment without
the clouds and thunderstorms under conditions that guarantee
charged particles. That would be during a dust storm on a clear
sky day under low humidity conditions as often exist in Queen
Creek, AZ.

Cecil,

This is close to being an all-time RRAA classic.

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

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

8-)

73,
Gene
W4SZ

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