Giuseppe,
Is it the plant or the distribution cables?
Our open area test site was rendered unusable by a dirty insulator on a
nearby high voltage power pole. Whenever the weather was dry and windy we
had broadband noise from 30 MHz to beyond 400 MHz. We found the culprit
pole with a spectrum analyzer, log periodic antenna and a "baseball bat"(
actually it was a length of 2x4 lumber used like a bat). When we wacked the
culprit pole with the "bat", the noise pattern changed momentarily. There
was enough vibration from the wack even though the power pole was concrete
and of a substantial thickness to produce the change in pattern. (The power
company told us that they preferred that we didn't wack their poles. On the
other hand, it got their attention and action.)
The power company came out and unwound the high voltage cable and rewound it
on the insulators and the noise disappeared. We have not had a problem for
a couple of years now. Considering the broadband noise was 20 dB above FCC
limits, I am sure this would have interfered with TV and Radio signals in
the area. As this was primarily a commercial area, we may have been the
only ones bothered by it.
This may not be your friend's problem, but I could not help but notice the
similarity in the humid conditions compared to the dry conditions. Your
friend should try contacting the utility company. They do come out and
check things out eventually, at least in Florida they do.
Good luck,
Don Umbdenstock
Sensormatic
> ----------
> From: Rossi Giuseppe[SMTP:g.ro...@crf.it]
> Reply To: Rossi Giuseppe
> Sent: Friday, March 10, 2000 10:19 AM
> To: 'emc-pstc'
> Subject: broad band EM noise
>
>
> Dear collegue
> I've got a question to which I'm not able to responde:
> A friend of mine is complaining about the EM radiated (not conducted)
> noise
> coming from
> a electrical generation power plant ( I do not know the exact translation
> ,
> hope that is anyway clear)
> He told me that the phenomena is particulary annoying in case of dry
> weather
> and that there is no noise
> in case of rain or fog.
>
> Could you give me any hint or point me toward something to read ?
>
>
> Thank you
>
> Giuseppe Rossi
>
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