On 3/10/12 1:42 PM, Cqtestk4xs@aol.com wrote:
> My old station K4XS was about 1000 feet from some very big lines...in
> excess of 100KV. Although the lines were quiet sometimes, they exhibited
> lots
> of noise in the humid early morning. It was kind of a "hash" noise.
> People have told me it was from a coronal effect? In any case I would not
> choose to live near them again.
>
Leakage across dirty insulators. When it gets damp, some current starts
to flow across the surface and you get local field concentrations with
corona discharge.
ALso makes audio noise (particularly in ultrasonic area, where there
isn't a lot of other noise sources, so they can use acoustic techniques
to pinpoint it)
The worst thing is that it might not be from the insulators closest to
you.. it could be a long way away, and the noise propagates down the
lines to you.
Here in Southern California (and other places), they send a truck out
with a high pressure water jet to hose them off (live!) The spray
mechanism is specially designed to pulse the water so there's never a
continuous water path between insulator (and line) and the truck.
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