Please identify this interference.

[Laggard]

YouTube - What is this interference?

Happens randomly on various bands. Sangean ATS 803A with 100 feet of wire outside. Located in South Minneapolis.


Thanks for any help.

 

[WyoWabbit]

Sounds like video (does that even make sense???) Okay, it sounds like a TV video signal. Changes in the 'tone' are when the video image changes from one scene to another. Couldn't see your radio's frequency display, but it could be mixing with something else to give a resultant frequency. Tom

 

[Laggard]

It was around 9700 khz. Most of that band was affected by the interference.

 

[KI4AMD]

Powerline?

Sounds like powerline to me. My best guess is that somewhere nearby you have a powerline component arcing. I'm not saying it couldn't be video, they do sound a lot alike, but if it the sound is relatively constant when it's active and it covers a wide swath of spectrum my guess is powerline. FYI power companies are not allowed to produce harmful interference any more than any other entity. If you can track it down with a directional antenna and ask them to fix it they usually will.

 

[Laggard]

Thanks. I moved to this location recently but had the same problem at our last place which was in a different building but literally 200 feet from where we are now. I guess I'm thinking that I don't know that it has anything to do with anyone in our building.

 

[WyoWabbit]

If you do track it, look closely at the cable TV lines and connections, they are notorious for leakage. Tom

 

[WA1ATA]

If you can track it down with a directional antenna and ask them to fix it they usually will.

Or just use a small antenna and walk around your neighborhood and find out where it is strongest. Then report the pole number to your electric company. It may be nothing more than an arcing insulator.

 

[WA1ATA]

Happens randomly on various bands. Sangean ATS 803A with 100 feet of wire outside. Located in South Minneapolis.

It sounds like 60Hz. Obviously, the powerlines are at 60Hz.
Unfortunately, a television signal also has a lot of energy at 60Hz (the vertical field rate) and it could be interference from a nearby TV station or from the cable TV.

If it is problem of a TV signal overloading your radio front end, then using a smaller antenna will disproportionately reduce the buzz.

If it is powerline, then it will most likely be worse when you tune the radio to the lowest frequencies.

 

[bryan_herbert]

Ive been trying to track that same noise down here in my neighborhood too. At times the interference is so strong I have to unplug the antenna or just shut off the radio. Sadly, its not located in my apartment, possibly not even in my complex.

 

[k9rzz]

Power lines. 100% sure.

Must be a leaky insulator nearby -> loss of power for the utility which they will happily fix!

Give them a call, tell them you are getting interference on your shortwave, you are pretty sure it's from the power lines nearby because it is real loud, and tell them where you live. They will dispatch a truck or two in a few days and PRESTO, it will disapear!

 

[Token]

Not enough data in the noise to definately ID it, but there are clues.

It is a short duration pulse type noise, around 0.002 seconds pulse duration. The pulse interval is 0.0166 seconds, and a 0.0166 sec rep rate is 60 Hz.

Most likely it is powerline noise or something related to that. For sure, it is something associated with the power lines, although it is possible that it is something plugged into them that cycles at the line rate. This leaves out things like CFLs but not some other types of fluorescent lights.

If you live in a house, vs an apartment, start killing circuit breakers until the noise goes away. If the noise does not go away it is outside the house and will take other efforts to find.

T!

 

[bryan_herbert]

Dont know about Laggard but Ive already unplugged and killed circuits. At times its so bad it kills AM and FM broadcast reception as soon as you pull in front of the building. No fixed time, sometimes in the morning, sometimes in the middle of the night. With me though it REALLY likes 5-6 MHz and anything between 13-20 MHz. Signal strength like I said is enough to kill AM and FM broadcast reception so S9+60dB on HF.

 

[WA1ATA]

With me though it REALLY likes 5-6 MHz and anything between 13-20 MHz. Signal strength like I said is enough to kill AM and FM broadcast reception so S9+60dB on HF.

Have you tried to localize it by wandering around your apartment complex with your radio, with no antenna or just a foot or two of wire?

A quarter wavelength at 5-6MHz is about 40 feet. So the noise source might be attached to a wire with effective length of 40 feet. That 40' length of wire would also be a pretty good radiator at the 3rd harmonics up around 15-18MHz. And then again around the 5th harmonics of 25 to 30MHz.

Problems in powerlines themselves generally show up strongest at lower frequencies.

If it is a noisy motor, you generally can hear some other tones besides 60Hz, and things like vacuum cleaners, mixers and other cheap universal motors aren't normally run for very long at a time.

Bryan and Laggard ..... if you ever do find the cause of the noise, please come back and educate us.

 

[bryan_herbert]

That would make sense. 30 MHz clear up through 6 meters (minus the clear 25 KHz or so gap every 1 MHz) just cannot be listened to here, variable S5-S9 depending on the antenna I use. One thing I do have to point out is every few MHz on .7500 KHz is tv audio. For example 149.7500 MHz. We do have ATT Uverse broadband with WiFi. Most of the complex if not the neighborhood has Time Warner Cable. Ive walked the whole building and its a pretty solid signal, right now 20 meters is completely unusable the signal meter is reading S7 and bouncing. I narrowed down one source that would stop my scanner on 121.5000, that source was my TV. It is still unplugged along with my cable box, I will not be plugging them back in. The DVD player on the laptop I'm on now has a really bad problem between 160-170 MHz on multiple frequencies so I use it as little as possible. I've been battling this issue a few months now and I'm ready to bring some outside help in. I'm not allowed to put up an antenna here so my only hope of getting on the air is going portable or solving the RFI issue and installing a loop in the room here.

 

[datainmotion]

While I generally defer to K9RZZ and Token, I'm going to have to disagree with them on this one. I believe that is the horizontal sync from a CATV video carrier, and a nasty one at that. I'd say contact Time Warner and tell them that there is a bad signal leak in your area.

Having said that, check the link in my sig for tips on finding it.

Good luck!

 

[bryan_herbert]

Literally, the only time I get piece and quiet on HF is during a neighborhood wide blackout.

 

[datainmotion]

Literally, the only time I get piece and quiet on HF is during a neighborhood wide blackout.

Bryan - unfortunately, living in an MUD (multi-unit dwelling in CATV speak) means there is a statistically higher chance of signal leaks due to the large number of connections in a small area. This is also compunded when there are multiple buildings in the complex.

I would contact the CATV company in your area and have them come out and find the leak(s).

 

[k9rzz]

Power Line Noise #2

YouTube - UKQRM Video showing the interference caused by BT Vision

 

[jim202]

[Simple question, does the noise change with the weather?

Like does the noise get better or worse when it rains?

Does the noise change with the wind? Like the harder it blows, the worse it gets.

 

[jackj]

It sounds like an electrical arc. Probably a power line insulator is cracked somewhere nearby. The crack will collect salt and dirt from the roads and then it will attract moisture causing the arc. Complain to the electrical power company, they should try to track it down and repair it.