[RFI] Power Line Noise

Michael Martin, RFI Services mike at rfiservices.com
Fri Apr 17 06:48:48 EDT 2020

Yes, what he said!
Ed is absolutely correct and in the RFI industry this happens every day.

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Michael Martin

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On Apr 17, 2020, 1:07 AM, at 1:07 AM, "Hare, Ed  W1RFI" <w1rfi at arrl.org> wrote:
>This is a key point, Mike.  Many noise sources that might be very
>strong when you are right on top of them are not heard at all at the
>amateur station.  This is why the signature method is the only really
>efficient way to identify the actual soure of an interference problem.
>Some hams get in their cars, drive around and find noise sources and
>assume that they are all causing them part of their inferference.  This
>is not usually the case.  Others truly do go on a crusade, feeling that
>if they force the utility to fix all the noise on their system, their
>noise environment will be quieter.  Some mistakenly think that any
>noise source they can hear 3 feet away under a pole is breaking FCC
>rules and so must be fixed.  All of these premises are flawed.
>There is one very big risk in finding dozens of noise sources and
>demanding that the utility fix them all.  The utlity may fix a few of
>them, if they aren't the one(s) you are hearing, they will often
>conclude that you are never going to be satisfied, so they may stop
>working on your case.  If your case then gets to the FCC, the utility
>will defend itself and say that it fixed noise sources, but you still
>have interference, so it must be from a non-utility source (and, if you
>don't have signature confirmation, that could very well be the case.)
>FCC rules do not require them to fix every noise source.  The rules set
>NO specific limits on indidential emitters, but only require that noise
>sources be corrected if they are causing harmful interference to
>licensed radio users.
>The bottom line is that it is important that the correct source(s) be
>identified and that you only ask the utlity to fix noises that are
>actually the one(s) causing interference.  Any other approach runs the
>risk of getting your case into an attorney letter-writing campaign that
>the FCC may well accept, making it all the harder for you to re-prove
>your case again and again.
>Ed, W1RFI
>From: RFI <rfi-bounces+w1rfi=arrl.org at contesting.com> on behalf of
>Michael Martin, RFI Services <mike at rfiservices.com>
>Sent: Thursday, April 16, 2020 6:25 PM
>To: K9MA <k9ma at sdellington.us>
>Cc: AA5CT via RFI <rfi at contesting.com>
>Subject: Re: [RFI] Power Line Noise
>Another observation I'd like to share.
>I commonly find powerline noise sources on poles in front of ham's
>homes that are very high in level but have no effect on their HF
>Often I find from the ham to the source as many as 10 to 15 power line
>noise sources before I get to the one that's affecting the ham.
>⁣RFI Services
>Michael Martin
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>On Apr 16, 2020, 6:16 PM, at 6:16 PM, K9MA <k9ma at sdellington.us> wrote:
>>On 4/16/2020 17:02, AA5CT wrote:
>>> re: "I went out today to track down a noise source, which on the
>>> HF bands appears to be coming from the east. "
>>> Scott, I give you even money odds that you found ANOTHER noise
>>> source on VHF, and not the one that was affecting you on HF (unless
>>> you already got it fixed, and that was it, in which case I lose hi
>>I doubt it. This source is just too incredibly loud at 135 MHz and
>>(maybe 300 feet from the antenna) that it can't possibly NOT be
>>HF interference. I agree with your point, though. When tracking at
>>I always hear lots of sources that are not the one causing the HF
>>problem. I deal with that by relaying the noise from the HF receiver
>>home so that I can hear it while I'm out tracking. There is always a
>>pattern to the fluctuations. When I find that they match, I know I've
>>got the right source. This is the same principle as taking the "noise
>>signature", without the expensive equipment. It has served me well.
>>I didn't bother this time because the source is so ridiculously strong
>>on VHF right out my front door.
>>Scott K9MA
>>Scott  K9MA
>>k9ma at sdellington.us
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>>RFI at contesting.com
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