Contributor:

Chip, N3IW

Noise Source: Unidentified

, possibly powerline noise?

Where Found:

Recorded at 3600 kHz in the 80 metre band, LSB with 2.4 kHz filter.

Notes:

S9+20 on a 40 metre dipole located 60 ft from powerlines. Not heard on other bands, and usually not noticeable on 40m. First recording was made with AGC on. Second recording was made with AGC off.

The waveform image is of n3iw-3600-no-agc.mp3 (with AGC OFF).

Click this link to listen:  www.arrl.org/files/file/RFI Sounds/n3iw-3600-no-agc.mp3

Contributor: Chip, N3IW
Noise Source: Unidentified.
Where Found: Recorded at 7020 kHz in the 40 metre band.
Notes: S9+20 on a 40 metre dipole located 60 ft from powerlines. Not heard on other bands, and usually not noticeable on 40m. Recording was made with AGC off.

Click this link to listen:  www.arrl.org/files/file/RFI Sounds/n3iw-7020-no-agc.mp3

Contributor: Pete, N4ZR
Noise Source: Unidentified
Where Found: Found from 28,625 to 28,700 kHz.
Notes: Recorded in AM mode. Note the pulsing in n4zr-new-10m-noise.mp3.

Click this link to listen:  www.arrl.org/files/file/RFI Sounds/n4zr-new-10m-noise.mp3

Contributor: Pete, N4ZR
Noise Source: Unidentified
Where Found: Found from 28,625 to 28,700 kHz.
Notes: Recorded in AM mode. Note the pulsing in n4zr-new-10m-noise.mp3.

Waveform image is of n4zr-10m-noise.mp3

Click this link to listen:  www.arrl.org/files/file/RFI Sounds/n4zr-10m-noise.mp3

Contributor: Barry, W2UP
Noise Source: Unidentified
Where Found: 10 metre band.
Notes: Recorded in AM mode with wide IF filter.

Click this link to listen:  www.arrl.org/files/file/RFI Sounds/w2up-whitenoise.mp3

Contributor:

Lou, AC0X

Noise Source: Unidentified
Where Found:

All through the HF spectrum, but stronger on 20/17/15 metres, but that may be due to a better antenna.

Notes:

Signal strength varies between S2 to S8 on those bands at different times. It can be heard 24/7, best with the beam at 240 degrees. Cannot be copied with a Grundig YB-400 portable in front of the house.

Waveform image is of ac0x-qrm-am.mp3

Click this link to listen:  www.arrl.org/files/file/RFI Sounds/ac0x-qrm-am.mp3

Contributor:

Lou, AC0X

Noise Source: Unidentified
Where Found:

All through the HF spectrum, but stronger on 20/17/15 metres, but that may be due to a better antenna.

Notes:

Signal strength varies between S2 to S8 on those bands at different times. It can be heard 24/7, best with the beam at 240 degrees. Cannot be copied with a Grundig YB-400 portable in front of the house.

Waveform image is of ac0x-qrm.mp3

Click this link to listen:  www.arrl.org/files/file/RFI Sounds/ac0x-qrm.mp3

Contributor:

Lou, AC0X

Noise Source: Unidentified
Where Found:

All through the HF spectrum, but stronger on 20/17/15 metres, but that may be due to a better antenna.

Notes:

Signal strength varies between S2 to S8 on those bands at different times. It can be heard 24/7, best with the beam at 240 degrees. Cannot be copied with a Grundig YB-400 portable in front of the house.

Waveform image is of ac0x-qrm2.mp3

Click this link to listen:  www.arrl.org/files/file/RFI Sounds/ac0x-qrm2.mp3

Added July 9, 2004
Contributor: David, K1TTT
Noise Source: Unidentified
Where Found: All through the HF spectrum, but stronger on 75 and 80 metres, but that may be due to a better antenna.
Notes: "This recording was made at about the loudest peak I found at 4125 kHz, AM mode, 6 kHz wide filter. As you can hear it is pulsing about 2 or 3 beats per second. This noise repeats at irregular intervals from at least 3410 to 4365 roughly every 30 - 60 kHz, in between the peaks there is virtually no trace of it. The pulsing is not in sync on all the peaks. It seems to disappear when the temperature gets below about 10 F but otherwise is very consistent across wide temperature and humidity ranges. The noise is much stronger along a fairly short stretch of rural road between about 3 houses 1/2 mile from my station. I need a better low freq df antenna to get closer now though. I have had the nearest home owner turn off his main breaker which did not affect the noise. It gets weaker near the other two houses so I am guessing its power line created somehow."
The interesting thing about this noise is that unlike noise from our electrical power system, this doesn't have a 60 Hz component. The "hash" you hear in the the file is pretty evenly spread out from about 1250 Hz to 2600 Hz. Does that ring any bells with anyone? --- Ken, VE3HLS

Click this link to listen:  www.arrl.org/files/file/RFI Sounds/k1ttt-4125-am.mp3

Contributor: Jacques, VE3VIA
Noise Source: Unidentified
Where Found: 18 kHz (yes, that's kilohertz!) in the VLF band.
Notes: It sure sounds like some kind of data transmission. Not necessarily RFI, but unidentified and interesting nonetheless --- Ken, VE3HLS

Click this link to listen:  www.arrl.org/files/file/RFI Sounds/18khz.mp3

Added January 24, 2005
Contributor: Daniel, K0DLW
Noise Source: Unidentified
Where Found: 75 and 80m band
Notes: "Makes no difference day or night, have attempted for approx three years to ID this with out success. Can notch it out with filters but would like to know what it is. Almost sounds like some sort of data transmission. It will keep the same cycle 24 hours a day."

Click this link to listen:  www.arrl.org/files/file/RFI Sounds/k0dlw-vox.mp3

Added January 24, 2005
Contributor:

Terry, KJ7F

Noise Source: Unidentified
Where Found:

400 to 460 MHz

Notes:

"Here is a recording of a noise source for your web page. It recently appeared at my QTH. It is on 24/7. It covers the entire 432 - 434 MHz segment that my transverter covers. I have tried different preamps to make sure that there isn't something wrong with them. Finally I borrowed a spectrum analyzer to rule out my radio equipment. The interference seems to cover from 400 MHz to 460 MHz but it's hard to know for certain since there are many licensed transmitters in that frequency range."

Click this link to listen:  www.arrl.org/files/file/RFI Sounds/kj7f-noise.mp3

Added January 24, 2005
Contributor: Frederico, PP8KWA
Noise Source: Unidentified
Where Found: 10m Band
Notes: "I have this noise in the band of 10M in the frequency of 28.400. Very irritating."

Click this link to listen:  www.arrl.org/files/file/RFI Sounds/pp8kwa-090952.mp3

Added January 24, 2005
Contributor: Dave, W7OJT
Noise Source: Unidentified
Where Found: 2m Band
Notes: "Enjoyed your QRN sampler, misery loves company I guess. Here's one that tears me up on 2m weak signal work... around 144.100. It consists of 2 second noise pulses with a small gap between them. I heard it once on 6m. Seems to be coming from about 5 blocks away but haven't narrowed it down yet to a single home. Maybe you or a visitor to your website can suggest a cause."

Click this link to listen:  www.arrl.org/files/file/RFI Sounds/w7ojt-worst.mp3

Added January 24, 2005
Contributor: Chris, KB7YOU
Noise Source: Unidentified
Where Found: From 160m to 10m with some gaps.
Notes: "Here is a sound that nobody (so far) has been able to ID. I have not heard it in a few months but last winter it was an almost nightly occurrence. It's strong enough to disrupt an S9+ signal. It covers all bands from 160m to 10m with some gaps. But, the gaps change from night to night. It's strength varies and the time of occurrence also varies but it's always in the evening/early morning. 20:00 to 04:00. I'm dreading it's return. Hams in my area 1 mile away here this, so it's either not local or really strong. When it returns, I'll do more range tests."

Click this link to listen:  www.arrl.org/files/file/RFI Sounds/kb7you-2004-01-29.mp3

Added January 24, 2005
Contributor: Gary, VE7GGJ
Noise Source: Unidentified
Where Found: Across the 80m band.
Notes: "I am trying to track down some noise here in Victoria. It sounds almost identical to your Sony-TV.mp3 file, but mine is in the 80 meter band. Here is a recording taken this morning on 3.648 LSB. It can be heard all across the 80 meter band on these frequencies: 3.244, 3.381, 3.516 3.648, 3.786, 3.922, 4.057, 4.193, 4.328, 4.462, 4.597, 4.733. These sure look like harmonic frequencies to me. I went so far as to power off my house at the breaker panel to determine if the source is inside my house. The noise was still there. All of my TVs are Toshiba, with the exception of a 25 year old Sony that the kids use for video games. At the time of this writing, the noise is not present and the Sony and other TVs have been switched off and on to try to replicate the problem. One other possibility is the Sharper Image N4EKV Ionic Breeze submission, but it does not sound nearly as close as the Sony TV noise."

Click this link to listen:  http://www.arrl.org/files/file/RFI%20Sounds/ve7ggj-3648lsb.mp3

Added January 24, 2005
Contributor: Fred, K6DGW
Noise Source: Unidentified
Where Found: 14050 kHz
Notes: "The attached MP3 is of one burst of a strange signal that I hear a lot on 14050 KHz. It was running about S5 at 18 Jan 2005 2300Z when I made the recording although at times, it has been S9+. It is quite broad band, and can be heard for (+-) 15 KHz or so, and almost sounds like it is sweeping up or down just a bit. Because it is so broad band, it's hard to determine its exact signal strength. Each burst is about 1-3 seconds long. Last Sun, I was listening to the Elecraft Net, and heard what sounds like an "exchange" ... etc. I've been hearing it for many months now. The interval between bursts varies a great deal from many many minutes to . Probably more than 70% of the time, it's just one burst followed by an interval of a 1-5 minutes. The rest of the time, there seems to be some sort of exchange going on, or multiple transmissions from the same station. It's never on long enough to swing the beam to peak it, although I've heard it as most all the azimuths I tend to work. This may be because the source is within a few hundred miles and the signal arrival angle is so high that the beam shows little F/B ratio. FWIW: My QTH is about 35-40 miles from Beal AFB which is (or was) home to a Pave Paws OTH radar. So far as I know, it operated in the general vicinity of 70cm, however, and I don't know if it is still operating. It is also home to a couple of recon/intelligence outfits, including the Predator UAV and the lone SR-71 still flying."

Click this link to listen:  www.arrl.org/files/file/RFI Sounds/k6dgw-14050.mp3

Added January 24, 2005
Contributor:

Matt, KQ7W

Noise Source: Unidentified
Where Found:

17m band.

Notes:

"Here is my clip...17 meters...AM first half, SSB 2nd half... Sounds like powerline noise to me? The thing is that is constant...but sometimes it's off, thats why I was thinking it might be someone just flipping a switch somewhere. I just put up a real antenna (just a windom) and I notice it more now. This morning it kicked in around 9 am from absolutely NO noise to this horrible S9 noise. I can blank most of it with the TS-870 noise blanker, but obviously can't work much when the band is full of signals due to IMD and overload from the blanker...especially in contests which I always get on.

PS : I just have a next door neighbor with some kind of a vent in his attic, I will go out and see if his vent is OFF when the noise if off, will try to analyze daily hour patterns and see if its a business hours related noise, but again, sounds like a bad powerline noise to me? Let me know if you can identify it. I will call the power company to check the transformers out here if possible."

Click this link to listen:  www.arrl.org/files/file/RFI Sounds/kq7w-noise-17m.mp3

Added April 24, 2005
Contributor: Bert, F6HKA
Noise Source: Unidentified 50 Hz AC
Where Found: S-9 on all HF bands
Notes: "Hi Ken, All have been recorded in AM mode. It is what I hear in my location every day 24/24 with a S9 level with peaking to 40dB. I have this QRM on all HF bands. I do not know where it comes from but I try to find that. Hope to give good news soon."

Click this link to listen:  www.arrl.org/files/file/RFI Sounds/f6hka-7mhz-am.mp3

Added April 24, 2005
Contributor: Morgan, SA0AED
Noise Source: Unidentified, 50 Hz AC
Where Found: 40m band
Notes: "Here is my contribution of an QRM noise thats is bothering me. It's found mainly in the 80- and 40-metersband, but can also be found in other band as well. In the 40-meters band the QRM is approx. between 6.930 - 7.056 Mhz and then it suddenly drops. The enclosed wav-file is recorded at 7,000 KHz 2005-03-25 ,19.52 UTC. I've not been able to identify the source of the QRM."

Click this link to listen:  www.arrl.org/files/file/RFI Sounds/sa0aed.mp3

Added April 24, 2005
Contributor: Jim, W0SR
Noise Source: Unidentified, strongest at a nearby manhole
Where Found: 150 MHz
Notes: "The attached noise was recorded today by the power company noise technician at 150 MHz. It is very localized (50 to 75 feet max) at the intersection of two streets a few hundred feet from my house. It seems to be loudest at the manhole cover! The noise levels are so high (S8 to S9 on 20-10) at my house I cannot hear it. Any ideas? Thanks."

Click this link to listen:  www.arrl.org/files/file/RFI Sounds/w0sr-noise-manhole2.mp3

>> NEW - August 2, 2005 <<
Contributor:

Frank, W0ECS

Noise Source: Unidentified, but seems computer/internet related
Where Found:

14,028 to 14,034 kHz and other areas

Notes:

"I've avoided this s5 to s7 noisy area at several QTHs, but now I've rediscovered the joy of DX hunting recently and I hate to give up this part of the 20m band.

I've asked other hams about this and many, but not all have experienced this. I'm not looking for anything peculiar to my current (2nd floor apartment) QTH because I heard it in our home and other apartments. The same sounding interference is on the low end of 30m as well - around 10.106 to 10.108.

Is this a generic sort of city dweller problem one has to put up with or can it be addressed?"

Note that in w0ecs-rfi1.mp3 Frank is slowly tuning through the noise on 20m. In w0ecs-rfi2.mp3 his receiver is stationary on 14,029.79 kHz....Ken

Click this link to listen:  www.arrl.org/files/file/RFI Sounds/w0ecs-rfi1.mp3

>> NEW - August 2, 2005 <<
Contributor:

Frank, W0ECS

Noise Source: Unidentified, but seems computer/internet related
Where Found:

14,028 to 14,034 kHz and other areas

Notes:

"I've avoided this s5 to s7 noisy area at several QTHs, but now I've rediscovered the joy of DX hunting recently and I hate to give up this part of the 20m band.

I've asked other hams about this and many, but not all have experienced this. I'm not looking for anything peculiar to my current (2nd floor apartment) QTH because I heard it in our home and other apartments. The same sounding interference is on the low end of 30m as well - around 10.106 to 10.108.

Is this a generic sort of city dweller problem one has to put up with or can it be addressed?"

Note that in w0ecs-rfi1.mp3 Frank is slowly tuning through the noise on 20m. In w0ecs-rfi2.mp3 his receiver is stationary on 14,029.79 kHz....Ken

Click this link to listen:  www.arrl.org/files/file/RFI Sounds/w0ecs-rfi2.mp3

Added:  February 26, 2010

Contributor:  Roland, AH6RR

Noise Source:  Unidentified

Where Found:  I have this noise that I can hear on my radio TS-850S
any filter combo from 8.MHz (S7-8) to 15.9(S9++ S9+ on 20Meters).
I also get it on 80M (S2-5) and 10M (S1-5) it is to the south of me but
it has made 20 Meters useless because even with the beam pointed
away from it is still S7-8. I need help in identifying this noise.

Click this link to listen:  www.arrl.org/files/file/RFI Sounds/ah6rr-20m-noise.mp3

Added:  April 17, 2010

Contributor:  John, AA9UF

Noise Source:  Unidentified

Where Found:  HF Bands

Click this link to listen:  www.arrl.org/files/file/RFI Sounds/aa9uf-unid-041710.mp3

Added:  March 13, 2010

Contributor:  Jay, N4NUI

Noise Source:  Unidentified

Where Found:  This signal appears on 20 Meters on an intermittent
basis almost every day. It is very broad, sweeps in frequency and
appears to be unidirectional.

Click this link to listen:  www.arrl.org/files/file/RFI Sounds/n4nui-20m-noise.mp3

Contributor:  Chris, KJ6BBS

Heard on 21.295 MHz USB on 2011-08-21, 19:20:45 UTC.

No measurement from signal meter.

Click this link to listen:  files/file/RFI%20Sounds/201108211910.mp3

Learn More

The latest challenge in my ham radio life is trying to uncover the
source of an interference issue that I have experienced on 10 meters for
about the past 2 weeks.

The interference is consistent, in that it occurs at all times of the
day.

I only get the interference on 10 meters, but it occurs throughout the
band.

Thanks and 73 from Tom Behler: KB8TYJ, Big Rapids

 Click this link to listen: files/file/RFI%20Sounds/KB8TYJ%20-%2010meter%20Unid.mp3

 
Learn More

W7PDX EMI

When monitored in SSB, the noise is an alternating high-speed motorboating with occasional bursts of what sounds like digital data.  In AM, it sounds like an alternating two-tone, high-pitched buzzing.  The interfering signals occur every 23-24 kHz between 80M and 15M.  The signals start at 9:00 am and end at 9:00 pm.  Signal strength is 10-15 dB over S9 on my Kenwood TS-870.

AM Mode EMI signal shown to right

Click this link to listen:  files/file/RFI%20Sounds/W7PDX_EMI-AM.mp3

 SSB Mode EMI signal shown to right

Click this link to listen:  files/file/RFI%20Sounds/W7PDX_EMI-SB.mp3

 
Learn More

Harro Tesmann, DJ9SA submitted this sample of RFI he experienced on the low end of 10 meters at 28.020 MHz.
He's asking for help identifying the type and source of RFI.

AM Mode RFI signal shown to right

Click this link to listen:  files/file/RFI%20Sounds/QRM-10m-2012_11_19-AM-28020KHZ.mp3

 
Learn More