Ultrasonic detectors are tricky. They can confirm a noise source, but they are
prone to false positives from corona discharge, which generally does not cause
interference. They can also give false negatives. If a spark or arc is
occurring on the top of an insulator, or is otherwise blocked from ground view,
an ultrasonic detector at ground level may not hear it at all.
Within their constraints, though, they can be useful. If a source is located to
a pole, the ultrasonic dish can pinpoint the source pretty accurately, if it
hears it. An ultrasonic sniffer can be used to pinpoint sources as well, and in
general if a utility worker can't hear the noise from a suspect component with
a sniffer, it is usually the wrong component, and possibly even the wrong pole.
The IEEE EMC Society has formed a working group that is developing an IEEE
Recommended Practice that explains all of the issues, techniques and offers
procedures electric utilities can use to respond to interference complaints. It
is in the final drafting stages and should go to ballot within a few months. I
am hoping that this will go a long way to helping utilities understand their
responsibilities and to know better how to fix it.
Ed, W1RFI
________________________________
From: Stephanie WX3K <wx3k@ptd.net>
Sent: Saturday, September 11, 2021 8:08 PM
To: Hare, Ed, W1RFI <w1rfi@arrl.org>
Cc: Rfi List <rfi@contesting.com>; jim@audiosystemsgroup.com
<jim@audiosystemsgroup.com>
Subject: Re: [RFI] Working with Utilities
“They are not responsible for noise from non-utility equipment and a few false
complaints can quickly put amateurs to the bottom of their priority list, often
not scheduled until Nevuary.
Ed, W1RFI“
Yep i understand that Ed. My reported RFI is certainly related to
humidity/temperature. It has really Again if the utility is only using their
ultrasonic detector, they really will not know if a line is severely
oscillating at 50 Mhz. If they find nothing with their detector they may brush
it off as a false complaint, right ? Again i have no issues with the PPL lines
because they replaced all the old Bell type insulators. I have not had that RFI
powerline signature since on any of their lines in the neighborhood.
My impression is MetEd needs some further understanding of RFI related to these
old Bell type insulators. They seem obstinate about replacing them.
Stephanie WX3K
> On Sep 11, 2021, at 5:04 PM, Hare, Ed, W1RFI <w1rfi@arrl.org> wrote:
>
> source before complaing to the utility. They are not responsible for noise
> from non-utility equipment and a few false complaints can quickly put
> amateurs to the bottom of their priority list, often not scheduled until
> Nevuary.
>
> Ed, W1RFI
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