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Old March 8th 07, 08:34 PM posted to
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First recorded activity by RadioBanter: Aug 2006
Posts: 1,027
Default Question about radio noise

On Mar 7, 10:52?pm, wrote:
Hi. I know nothing about amateur radio nor electronics so I'm here looking for
an answer to a question which bothers me. There are a number of places near
where I live that, if you drive by them with the AM radio in the car on, there's
an extreme amount of noise. It usually last while driving parallel to overhead
wires (not high power lines, must the ones on poles), then goes away. It's
always the same places and doesn't come or go. I'm guessing bad shielding of the
wires. My concern is, if it does this to the radio, is it harmful to people who
are near it? Thanks.

Like Steve remarked, the noise you hear isn't harmful.

Overhead electric power distribution lines aren't shielded.
With time and exposure their insulators, even the wire
(if covered with insulation) will accumulate semi-conducting
dirt and grime. That can cause minor to major arc-overs
which are short-impluse energy spikes. Since those are
of very short duration their bandwidth is wide and can
spread the impulse energy up into the VHF range of
FM broadcast band.

In newer construction the electric power distribution
lines are underground, generally through metal conduit,
and don't get a change to radiate wideband RF energy
nor are there as many arc-overs.

If the irritation from picked-up noise is a bother, it can
be reported to the local power utility. It's touch and go
whether or not they do anything about it, though. It is
only an irritant to radio listeners and not harmful to any
human...but it is covered by FCC regulations as
"incidental, unintentional RF radiation" and has limits.

73, AF6AY