Thanks Jim.
Although I didn't mention it before, this is at least the fourth time that I've
dealt with such things over the years. In every case, I had succeeded using
the simple method described before.
I hadn't gone into a lot of detail before, but should say that the two poles
that I found gave almost full-scale readings on the MFJ noise meter within
about 50 feet. Both had pole-mounted transformers. The worst one had a
transformer that was completely rusted on the outside. Other noisy poles that
I encountered barely gave an indication on the noise meter even though they
were fairly loud on the AM car radio.
Since my QTH is rural with very few neighbors all very far away, the background
noise level (excluding atmospheric and solar QRN) is typically about S-zero on
160M using 50-100 Hz bandwidth on a K3S fed by Beverage antennas. That would
explain why I'm detecting interference sources much farther away than you (and
others) have been able to detect.
73, Riki K7NJ
From: AA5CT [mailto:jwin95@yahoo.com]
Sent: Tuesday, June 07, 2022 8:00 AM
To: Riki, K7NJ; rfi@contesting.com; Hare, Ed, W1RFI
Subject: Re: [RFI] Power Line Radiated Interference Limits
re: "Although it is remotely possible to hear a noise with a
source 7 miles away, it is very unlikely."
My distance record to a source on 160 meters was 5.46 miles to
a distribution line run along Sam Rayburn Tollway (SH-121).
This took some work to identify, and I ran into several low-level
sources in between. But, continued 'bearings' (incl compass
readings and 'map work') to the SH-121 location was the ONLY
way I found this one. This one was 'run down' over a several
day period ...
2nd longest was 4.23 miles to a pole on SouthFork Ranch
property. I have a video of the visible arc and audio (of the arc
on this 2nd one). This noise source was also bothering a station
on the 80 meter band 2.5 miles east of SouthFork as well.
It was an FEC - Farmers Electric Cooperative - pole.
And remember, on ground wave on top band its no longer 'inverse
square law' (free spaces path loss), but more like just inverse law.
The most reliable technique I have found is to DF from my station
TO the source, continuously monitoring and 'nulling' the source
using the “Coastal Navigator” model number FR-662B.
This DF receiver has a knob on the top panel that allows the ferrite
loopstick to be rotated back and forth, giving the direct bearing to
the source *when* the null occurs. There is also a sense function
that yields a cardioid antenna pattern allowing the unique bearing
to the source to be identified. With this I 'drive' (or bicycle) directly
to the source, although a 'spiral' course into the source allows a
probable identification of the center of that spiral to be identified
Someone else on this list not too long ago also recommended DFing
to the source before 'springing' to a conclusion as to what is
causing the actual noise.
I had what sounded like broad-band arc noise come from a residence
3900 feet to my NE ... it was coming from a residence, and ALL the
homes in that subdivision area have underground distribution mains ...
could it still have been underground powerco equipment? Yes, but it
went away after a few weeks so that was the end of that ... I made
multiple visits/passes through the alleyway and on the streets during
that exercise over a number of days, just to confirm methods and
results.
de AA5CT Jim
On Tuesday, June 7, 2022, 6:40:17 AM GMT-5, Hare, Ed, W1RFI <w1rfi@arrl.org>
wrote:
Although it is remotely possible to hear a noise with a source 7 miles away,
it is very unlikely. You really need to establish correlation between your
noise and ones found in the field.
The most reliable way to do that is with a signature technique, such as used by
the Radar Engineers noise locator.
One can also track it carefully from your home, but this requires that you are
able to hear it from your driveway using a portable or mobile receiver. If you
hear the noise and it gets steadily stronger as you drive towards the suspect
source, that can be a reasonable correlation. (There will be standing waves on
the line, so the noise will get louder and softer as you drive down the line.
If you aak the power company to repair noise sources you can't hear and thus do
not fix your problem,. they will very quickly lose confidence in your
complaints and stop working on your problem.
________________________________
From: RFI <rfi-bounces+w1rfi=arrl.org@contesting.com> on behalf of Riki, K7NJ
<k7nj@awinets.com>
Sent: Monday, June 6, 2022 11:42 PM
To: rfi@contesting.com <rfi@contesting.com>
Subject: [RFI] Power Line Radiated Interference Limits
A few more notes:
The farthest source that I located is about 7 miles away, and the closest
one is about 1.5 miles away. As mentioned before, there may be more, but for
now, this is a good starting point.
I was able to DF the approximate direction with the help of three
bi-directional Beverages. So, I generally knew in what direction to search
in. In summary, nothing sophisticated was used - just a simple, common
sense, basic ham approach.
73, Riki K7NJ
-----Original Message-----
From: RFI [mailto:rfi-bounces+k7nj=awinets.com@contesting.com] On Behalf Of
rfi-request@contesting.com
Sent: Monday, June 06, 2022 8:29 PM
To: rfi@contesting.com
Subject: RFI Digest, Vol 233, Issue 5
Send RFI mailing list submissions to
rfi@contesting.com
To subscribe or unsubscribe via the World Wide Web, visit
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or, via email, send a message with subject or body 'help' to
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You can reach the person managing the list at
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When replying, please edit your Subject line so it is more specific
than "Re: Contents of RFI digest..."
Today's Topics:
1. Re: Power Line Radiated Interference Limits (Charles Plunk)
2. Re: Power Line Radiated Interference Limits (AA5CT)
3. Re: Power Line Radiated Interference Limits (Steve Dyer)
4. Re: Power Line Radiated Interference Limits (Charles Plunk)
5. Re: Power Line Radiated Interference Limits (Dave (NK7Z))
----------------------------------------------------------------------
Message: 1
Date: Mon, 6 Jun 2022 19:15:12 -0500
From: Charles Plunk <af4o@twc.com>
To: rfi@contesting.com
Subject: Re: [RFI] Power Line Radiated Interference Limits
Message-ID: <1dc6f868-2232-ec93-0d52-3aa7891b174b@twc.com>
Content-Type: text/plain; charset=UTF-8; format=flowed
I snooped on your QTH. Nice remote area with single phase lines. I am
jealous :-).
73 Chuck W4NBO
On 6/6/22 18:21, Riki, K7NJ wrote:
> 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-----
> From: RFI [mailto:rfi-bounces+k7nj=awinets.com@contesting.com] On Behalf
Of
> rfi-request@contesting.com
> Sent: Monday, June 06, 2022 5:28 AM
> To: rfi@contesting.com
> Subject: RFI Digest, Vol 233, Issue 3
>
> Send RFI mailing list submissions to
> rfi@contesting.com
>
> To subscribe or unsubscribe via the World Wide Web, visit
> http://lists.contesting.com/mailman/listinfo/rfi
> or, via email, send a message with subject or body 'help' to
> rfi-request@contesting.com
>
> You can reach the person managing the list at
> rfi-owner@contesting.com
>
> When replying, please edit your Subject line so it is more specific
> than "Re: Contents of RFI digest..."
>
>
> 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@awinets.com>
> To: <rfi@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
>
>
>
------------------------------
Message: 2
Date: Tue, 7 Jun 2022 01:08:40 +0000 (UTC)
From: AA5CT <jwin95@yahoo.com>
To: "rfi@contesting.com" <rfi@contesting.com>, Charles Plunk
<af4o@twc.com>
Subject: Re: [RFI] Power Line Radiated Interference Limits
Message-ID: <936942320.93901.1654564120029@mail.yahoo.com>
Content-Type: text/plain; charset=UTF-8
Won't he be surprised when it DOESN'T cure the problem; I just
tracked down a source I had on 160 meters that was 1.74 miles
(that's one point seven four miles) away. This was 'tracked' down
using a portable battery-operated marine DF receiver using a
bicycle as mode of transportation. Multiple DF readings were
taken on this source until I finally converged on the source.
Some of these sources can be quite some distance away, and any
nearby sources located may not be the one creating all the havoc
at the station QTH. I've had a couple of those, too. By using the
DF receiver I can take bearings some distance out from the
actual, final 'source' and feel quite confident I've located the
source that affected my station QTH. Also note, when I find
one of these sources a mile or more out, standing 30 feet away
from the actual source the noted signal strength is quite strong.
I make use of and note of the RF gain control setting on the DF
receiver too. As there is no AGC on these model marine DF receivers,
its necessary to 'wind back' the RF gain as one begins to converge
on the noise source. One gets a repeatable indication when locating
these sources and noting that the RF gain setting is near minimum
to keep the meter 'mid-range on scale' when one finally locates the
actual, physical RFI source.
de AA5CT Jim
On Monday, June 6, 2022, 7:15:24 PM GMT-5, Charles Plunk <af4o@twc.com>
wrote:
I snooped on your QTH. Nice remote area with single phase lines. I am
jealous :-).
73 Chuck W4NBO
On 6/6/22 18:21, Riki, K7NJ wrote:
> 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-----
> From: RFI [mailto:rfi-bounces+k7nj=awinets.com@contesting.com] On Behalf
Of
> rfi-request@contesting.com
> Sent: Monday, June 06, 2022 5:28 AM
> To: rfi@contesting.com
> Subject: RFI Digest, Vol 233, Issue 3
>
> Send RFI mailing list submissions to
> ??? rfi@contesting.com
>
> To subscribe or unsubscribe via the World Wide Web, visit
> ??? http://lists.contesting.com/mailman/listinfo/rfi
> or, via email, send a message with subject or body 'help' to
> ??? rfi-request@contesting.com
>
> You can reach the person managing the list at
> ??? rfi-owner@contesting.com
>
> When replying, please edit your Subject line so it is more specific
> than "Re: Contents of RFI digest..."
>
>
> 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@awinets.com>
> To: <rfi@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
>
>
>
_______________________________________________
RFI mailing list
RFI@contesting.com
http://lists.contesting.com/mailman/listinfo/rfi
------------------------------
Message: 3
Date: Mon, 6 Jun 2022 18:19:45 -0700
From: Steve Dyer <w1srd@yahoo.com>
To: rfi@contesting.com
Subject: Re: [RFI] Power Line Radiated Interference Limits
Message-ID: <3a62b5ee-7216-d7e7-dd0b-961f7ecee318@yahoo.com>
Content-Type: text/plain; charset=UTF-8; format=flowed
For a quick and easy reading, the WSJT-X waterfall is quite useful. Just
drop the rig into AM mode and see the bright line at 120 Hz and
harmonics every 60 Hz across the whole pass band (at least at my QTH).
Be sure to set Start to 0 Hz. You can roll over the waterfall or the pan
with the cursor and read out the frequency.
I've also used Spectrum Lab to capture audio artifacts.
Soundcard Oscilloscope is useful to identify when you have multiple
sources by observing the pulse trains and measuring the times between
pulses. https://www.zeitnitz.eu/scope_en
Cant have too many tools.
73,
Steve
W1SRD
On 6/6/2022 13:24, Hare, Ed, W1RFI wrote:
> Actually, much powerline noise is rather steady, so it will show up as a
solid block on a waterfall. That is diagnostic that the noise is not coming
from a switcher, but will not differentiate conclusively between electrical
noise and perhaps noise caused by something not powerline-related at all.
The waterfall will not really identify 60- or 120-Hz modulation, so
demodulating in AM and looking at the resultant audio is an important step.
>
> Ed
>
>
> ________________________________
> From: RFI <rfi-bounces+w1rfi=arrl.org@contesting.com> on behalf of Jim
Brown <jim@audiosystemsgroup.com>
> Sent: Monday, June 6, 2022 1:45 PM
> To: rfi@contesting.com <rfi@contesting.com>
> Subject: Re: [RFI] Power Line Radiated Interference Limits
>
> On 6/6/2022 4:28 AM, Hare, Ed, W1RFI wrote:
>> 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.
> The best diagnostic tool, by far, to identify power line noise, as
> opposed to electronic noise, is a broadband WATERFALL of either a
> receiver's IF or RF. Powerline noise and lightning static is arcing, and
> will show up as horizontal lines on a slow waterfall.
>
> Electronic noise is the harmonics of square waves used in switch-mode
> power supplies and other power control electronics like variable-speed
> motor controllers, which show up as vertical humps of noise spaced at
> 10-50kHz, and microprocessor clocks, which sound like carriers and show
> up as narrow vertical lines.
>
> Power line and other impulse noise is present at all frequencies, but is
> best chased at the highest frequencies where it can be heard.
> Traditional techniques apply. Electronic noise must be chased on the
> frequencies where it is heard.
>
> More on this in this here.
> http://k9yc.com/KillingReceiveNoise.pdf
> <http://k9yc.com/KillingReceiveNoise.pdf%20> and
> http://k9yc.com/KillingRXNoiseVisalia.pdf
>
> 73, Jim K9YC
> _______________________________________________
> RFI mailing list
> RFI@contesting.com
> http://lists.contesting.com/mailman/listinfo/rfi
> _______________________________________________
> RFI mailing list
> RFI@contesting.com
> http://lists.contesting.com/mailman/listinfo/rfi
------------------------------
Message: 4
Date: Mon, 6 Jun 2022 21:14:53 -0500
From: Charles Plunk <af4o@twc.com>
To: "rfi@contesting.com" <rfi@contesting.com>
Subject: Re: [RFI] Power Line Radiated Interference Limits
Message-ID: <5bca0b93-8216-eb67-d2d8-a1dcc0aac8aa@twc.com>
Content-Type: text/plain; charset=UTF-8; format=flowed
Jim, I thought the same thing. That is my best lesson learned tracking
power line rfi. Noise seems to be everywhere when out tracking in the
field. Every pole has some around here near field. To be as sure of
success as possible you must find some way to track the -correct- noise.
No fun getting the util out and your findings be wrong.
I have been most successful (without spending high dollar on rfi gear)
retransmitting the noise from my station receiver to a HT -especially-
if I can catch it with a distinctive pattern. And comparing audibly with
a tracking ht with handheld yagi and/or ultrasonic dish. Fortunately
most of my power line rfi at some point will go intermittent with a
distinctive pattern usually varying with humidity. Patience is key here.
Sorry for repeating as I know I have told this story in the past but it
really made a huge difference in my ability to track down the right noise.
Many months now 120hz buzz free :-). Well some distant stuff but NB
works fine.
73
Chuck
W4NBO
On 6/6/22 20:08, AA5CT wrote:
> Won't he be surprised when it DOESN'T cure the problem
>
> and any
> nearby sources located may not be the one creating all the havoc
> at the station QTH.
>
> de AA5CT Jim
>
>
------------------------------
Message: 5
Date: Mon, 6 Jun 2022 19:29:16 -0700
From: "Dave (NK7Z)" <dave@nk7z.net>
To: rfi@contesting.com
Subject: Re: [RFI] Power Line Radiated Interference Limits
Message-ID: <ae644d93-d2b0-f178-5142-0049ceae88de@nk7z.net>
Content-Type: text/plain; charset=UTF-8; format=flowed
Hi,
I have a three part article at:
https://www.nk7z.net/sdr-rfi-survey-p1/
which may assist you in quantifying the RFI... It uses a SDR to show
you your RFI in a few different ways.
73, and thanks,
Dave (NK7Z)
https://www.nk7z.net
ARRL Volunteer Examiner
ARRL Technical Specialist, RFI
ARRL Asst. Director, NW Division, Technical Resources
On 6/5/22 19:12, 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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