[RFI] Power Line Radiated Interference Limits

Mon Jun 6 19:21:47 EDT 2022

Thanks Ed and Charles,

With all the great input from Ed, I now know the "lay of the land", i.e.
what administrative tools and regulations apply.  

I've located two power poles that are likely sources.  I drove around
listening on my car radio to the noise in a clear channel in the AM
broadcast band. When the noise peaked next to a power pole, I got out of the
car and did some direction finding with a portable AM radio (that has the
typical directional internal antenna).  Next, I verified the findings using
an MFJ-852 AC Power Line Noise meter. Everything was in agreement, so I made
note of the pole identification number (from its metal ID label).  I've
already contacted the power company, and they've issued a work order number.
They said that it might take a week or two, and if needed, I should call
them back.

Hopefully the problem will now be fixed, although there were many additional
power poles that caused much lower noise on the car radio.  But, this is a
good starting point for now.

73, Riki K7NJ

-----Original Message-----
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Sent: Monday, June 06, 2022 5:28 AM
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Subject: RFI Digest, Vol 233, Issue 3

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Today's Topics:

   1. Power Line Radiated Interference Limits (Riki, K7NJ)
   2. Re: Power Line Radiated Interference Limits (Charles Plunk)
   3. Re: Power Line Radiated Interference Limits (Charles Plunk)
   4. Re: Power Line Radiated Interference Limits (Hare, Ed, W1RFI)

----------------------------------------------------------------------

Message: 1
Date: Sun, 5 Jun 2022 20:12:02 -0600
From: "Riki, K7NJ" <k7nj at awinets.com>
To: <rfi at contesting.com>
Subject: [RFI] Power Line Radiated Interference Limits
Message-ID: <000401d8794a$d01cf890$7056e9b0$@com>
Content-Type: text/plain;	charset="us-ascii"

I've recently become plagued by power line interference that is most
noticeable on 80M and 160M.  In the past,, the local power company had been
cooperative in fixing the source(s) of such interference.  However it's been
about 7 or 8 years since I've been in touch with them about such issues.
Just to be prepared, I would like to know what specific limits there are on
power line emissions (if any).  I know that in the past, the requirements
were very lenient - only requiring power companies to follow good
engineering practice without any quantitative emission limits.  In any case,
having the actual reference paragraph numbers in the FCC rules would be most
helpful. As I recall, this had been somewhere in Part 15. Any help would be
appreciated. 

73, Riki K7NJ

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------------------------------

Message: 2
Date: Sun, 5 Jun 2022 22:27:44 -0500
From: Charles Plunk <af4o at twc.com>
To: rfi at contesting.com
Subject: Re: [RFI] Power Line Radiated Interference Limits
Message-ID: <a78c155d-a51d-b001-d4e6-b01850df5175 at twc.com>
Content-Type: text/plain; charset=UTF-8; format=flowed

Looking back in the archives of this group should yield what you seek. 
Pay particular note of Ed Hare's response on the subject for regulatory 
standards. Part 15 mentions "harmful". I guess what is harmful to a 
moonbounce operator maybe different from what is harmful to a 80m op. 
For me, as of the last 8+ months or so I am free of 120hz rfi except 
distance sources and they are very intermittent so I can easily live 
with that (sometimes using NB but not very often) and do not consider it 
harmful for me. But the 20db over S9 I use to have definitely was.

Here is a sample letter at the ARRL website which specifies the Part 15 
sections although it does not go into detail but I'm sure you could 
google that; https://www.arrl.org/fcc-power-utility-letter

Let us know how it goes.

73

Chuck
W4NBO

On 6/5/22 21:12, Riki, K7NJ wrote:
> I've recently become plagued by power line interference that is most
> noticeable on 80M and 160M.  In the past,, the local power company had
been
> cooperative in fixing the source(s) of such interference.  However it's
been
> about 7 or 8 years since I've been in touch with them about such issues.
> Just to be prepared, I would like to know what specific limits there are
on
> power line emissions (if any).  I know that in the past, the requirements
> were very lenient - only requiring power companies to follow good
> engineering practice without any quantitative emission limits.  In any
case,
> having the actual reference paragraph numbers in the FCC rules would be
most
> helpful. As I recall, this had been somewhere in Part 15. Any help would
be
> appreciated.
>
> 73, Riki K7NJ
>
>
>

------------------------------

Message: 3
Date: Sun, 5 Jun 2022 22:41:34 -0500
From: Charles Plunk <af4o at twc.com>
To: rfi at contesting.com
Subject: Re: [RFI] Power Line Radiated Interference Limits
Message-ID: <5119027b-ad7b-4c89-80c3-f03bb79f99dd at twc.com>
Content-Type: text/plain; charset=UTF-8; format=flowed

Oh, I would try to exhaust all other tactful ways of getting it fixed 
before pointing out reg's to them. If they worked with you 7-8 years ago 
then likely they will now. But I understand if you are trying to get 
prepared "just in case". Knowledge is power they say.

I would be prepared to explain to them why you believe its power line 
rfi and not another source. Such as a way of identifying the 120hz. 
There are ways to do this. I usually record the noise and expand it out 
on a audio manipulation program such as Audacity and count the 120hz 
spikes. Others do it differently.

And of course, you have shut down your main breaker to your house while 
powering a receiver on battery to try that first?

After doing those things, hope your power co is large enough to have RFI 
location gear. Mine is small thus I find the poles myself with my 
accumulation of various gear, some homemade :-).

73

Chuck
W4NBO

On 6/5/22 21:12, Riki, K7NJ wrote:
> I've recently become plagued by power line interference that is most
> noticeable on 80M and 160M.  In the past,, the local power company had
been
> cooperative in fixing the source(s) of such interference.  However it's
been
> about 7 or 8 years since I've been in touch with them about such issues.
> Just to be prepared, I would like to know what specific limits there are
on
> power line emissions (if any).  I know that in the past, the requirements
> were very lenient - only requiring power companies to follow good
> engineering practice without any quantitative emission limits.  In any
case,
> having the actual reference paragraph numbers in the FCC rules would be
most
> helpful. As I recall, this had been somewhere in Part 15. Any help would
be
> appreciated.
>
> 73, Riki K7NJ
>
>
>

------------------------------

Message: 4
Date: Mon, 6 Jun 2022 11:28:11 +0000
From: "Hare, Ed, W1RFI" <w1rfi at arrl.org>
To: Charles Plunk <af4o at twc.com>, "rfi at contesting.com"
	<rfi at contesting.com>
Subject: Re: [RFI] Power Line Radiated Interference Limits
Message-ID:

Content-Type: text/plain; charset="iso-8859-1"

Power lines are "incidental radiators" as defined by Part 15 rules. As such,
there are no specific radiated or conducted emissions limits for the noise
they make. The operator of an incidental emitter is required to use it in a
way that does not cause harmful interference.

Power line noise exhibits a few characteristics:

Power-line noise level is relatively constant across a particular band, +-
antenna resonance.  So, when you tune the band, its noise does not get
louder, quieter, louder quieter, but is pretty constant across the band.
Many other noise sources have noise that peaks every "N" kHz across the
band.

Power-line noise has a strong 120-Hz component, although in rare cases, it
can have a 60-Hz signature.  Put your receiver in AM mode, 6 or more kHz
bandwidth, and give a listen. You can also make a .wav or .mp3 file and run
it through a free program called 'Audacity" and analyze that spectrum, with
the understanding that your receiver bandwidth is usually limited below 200
Hz or so, so that 120-Hz component may be reduced in amplitude.

In the time domain, you may see spikes or a repeating 120-Hz pattern.
(Audacity does that, too).  The peaks sometimes vary fron the nominal
120-Hz, 8.3 MHz, as wind and vibration moves the gap that is causing the
noise around.

Power-line noise usually varies with weather, usually going away on rainy
days, but sometimes getting worse, and as wind blows lines around, the noise
can show variations.

Other devices like switching supplies have peaks and dips up and down the
band.  Switchers can be drifty, with the frequency of those peaks changing
as the device warms up and sometimes doing little jumps as voltages exhibit
small surges and dips. If the noise comes on suddenly in response to what
people are doing, it is usually a device. Switchers are used in almost every
electronic device made today, and they are sometimes confused with
power-line noise.

Here are the basic steps to follow:

o Determine that there is probable cause to think it is power-line noise
o Contact your power company through its customer-service representatives.
The key words are radio interference, television interference or even tell
them their help screens could be looking for "noise" or "RTVI."
o Give it time.  In about 25% of the cases we initiate from reports, we hear
back a week later saying that the power company was out to fix it.
o In most cases, the power company does not contact you, although it should.
So, no response doesn't mean that it is not being worked on.  The new IEEE
standard on power-line noise explains why it is important that the
power-company staff coordinate with complainants, but that is not in effect
yet.
o If that doesn't work, contact ARRL by filling out the intake form at:

 https://form.jotform.com/212425939918163

The Lab staff will then run through a process it has worked out with the FCC
to first have ARRL try to persuade your power company to work on and fix the
problem, then ultimately turn over a well-documented case to the FCC.

Ed Hare, W1RFI
ARRL Lab

REPORT OF POSSIBLE INTERFERENCE FROM ELECTRIC UTILITY TO AN AMATEUR RADIO
STATION<https://form.jotform.com/212425939918163>
Please click the link to complete this form.
form.jotform.com

________________________________
From: RFI <rfi-bounces+w1rfi=arrl.org at contesting.com> on behalf of Charles
Plunk <af4o at twc.com>
Sent: Sunday, June 5, 2022 11:41 PM
To: rfi at contesting.com <rfi at contesting.com>
Subject: Re: [RFI] Power Line Radiated Interference Limits

Oh, I would try to exhaust all other tactful ways of getting it fixed
before pointing out reg's to them. If they worked with you 7-8 years ago
then likely they will now. But I understand if you are trying to get
prepared "just in case". Knowledge is power they say.

I would be prepared to explain to them why you believe its power line
rfi and not another source. Such as a way of identifying the 120hz.
There are ways to do this. I usually record the noise and expand it out
on a audio manipulation program such as Audacity and count the 120hz
spikes. Others do it differently.

And of course, you have shut down your main breaker to your house while
powering a receiver on battery to try that first?

After doing those things, hope your power co is large enough to have RFI
location gear. Mine is small thus I find the poles myself with my
accumulation of various gear, some homemade :-).

73

Chuck
W4NBO

On 6/5/22 21:12, Riki, K7NJ wrote:
> I've recently become plagued by power line interference that is most
> noticeable on 80M and 160M.  In the past,, the local power company had
been
> cooperative in fixing the source(s) of such interference.  However it's
been
> about 7 or 8 years since I've been in touch with them about such issues.
> Just to be prepared, I would like to know what specific limits there are
on
> power line emissions (if any).  I know that in the past, the requirements
> were very lenient - only requiring power companies to follow good
> engineering practice without any quantitative emission limits.  In any
case,
> having the actual reference paragraph numbers in the FCC rules would be
most
> helpful. As I recall, this had been somewhere in Part 15. Any help would
be
> appreciated.
>
> 73, Riki K7NJ
>
>
>
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