[RFI] Power Line Noise

Michael Martin, RFI Services mike at rfiservices.com
Fri Apr 17 07:42:09 EDT 2020


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Michael Martin

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On Apr 17, 2020, 6:49 AM, at 6:49 AM, "Michael Martin, RFI Services" <mike at rfiservices.com> wrote:
>Thanks Ed your in foot is extremely valuable
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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. 
>>is not usually the case.  Others truly do go on a crusade, feeling
>>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
>>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
>>NO specific limits on indidential emitters, but only require that
>>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
>>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.
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>>Michael Martin
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>>On Apr 16, 2020, 6:16 PM, at 6:16 PM, K9MA <k9ma at sdellington.us>
>>>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
>>>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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