[TowerTalk] Rain static

[Tom Rauch]

> Does anyone have any ideas of how I can solve this
problem?

Joe,

There is some controversy or difference of opinion on this,
but my experience, everything I can measure or simulate, and
any data I get from other sources indicates the noise is
from corona discharge from sharp points in or around the
antenna. This corona discharge is caused by voltage gradient
between the earth and clouds around the antenna during
inclement weather.

The other opinion (that I do not find evidence to support)
is that charged droplets or particles hit the antenna and
discharge, making noise.

Regardless of the actual effect behind the noise grounding
the antenna or the fact it is a log periodic has nothing to
do with causing the problem or with sensitivity of the
antenna to noise. I have that problem with gamma matched
yagis just as much as with insulated elements. It occurs
with dc grounded elements the same as with floating
elements.

We spent weeks working on repeater and other communications
systems on tall buildings trying to eliminate that type of
noise. Lowering the antenna, making protruding antenna ends
blunter or more rounded or using insulated element tips,
installing something higher above the antenna to divert
charge to that other point and away from the antenna
elements, and eliminating sharp points on the tower and
antenna often help.


When I have that noise here I  switch to a lower antenna.

73 Tom