Music in the air

[mtnelectrical]

I do some renovations in old apartment buildings whenever the tenants move. Buiilding with brick walls some 4 o 5 floors maybe 30 to 50 apartments. I just finish one apartment 2 weeks ago. Super called me saying there is a humming sound coming from all the apliances when they power them up. Go there ask the lady to show me what appliances make that sound. She showed me first the TV, it is working and as soon it is turn off the TV start making a sound like interfirence the TV is off when does this, now to eliminate the sound you have to unplug it. Go to the computer she has the speakers of the desktop pc making the same noise, the pc is off and the speakers are humming again to make disappear you have to unplug it. Checked voltage and 119 volts receptacles were grounded and of course good polarity, But while I was connecting and disconnecting things I moved the wires for the transformers for the speakers, modem (internet) and the sound increases and decreases, specially when moving cat TV wire, The other day she said there was some Calypto music, I started to laugh and yes after a while we started hearing some music. Well it looks that the apatment has become an antenna. Question (finally) Does anyone has seen something like this before? and what can be done to correct it? Sorry for the long post

 

[LarryFine]

I'm guessing she lives near a radio station transmitter?

 

[mtnelectrical]

not that I know, and cable tv tecs were there today and said it was an electrical problem. Something I did was disconnect the cable frome the cable connector that goes the basement 9main connection of the bulding and still we heard music.

 

[satcom]

not that I know, and cable tv tecs were there today and said it was an electrical problem. Something I did was disconnect the cable frome the cable connector that goes the basement 9main connection of the bulding and still we heard music.

Yes, once in a building in Teterboro and another time a building in the Meadowlands, in both cases the nearby station towers had large ground systems.

 

[Speedskater]

Jim Brown the Audio Engineering Society committee chair on EMI/RFI and a HAM has several papers on radio interference.

http://www.audiosystemsgroup.com/publish.htm

But almost always it takes a loudspeaker and amplifiers to hear this interference.

 

[satcom]

Jim Brown the Audio Engineering Society committee chair on EMI/RFI and a HAM has several papers on radio interference.

http://www.audiosystemsgroup.com/publish.htm

But almost always it takes a loudspeaker and amplifiers to hear this interference.

Some people can hear it in their head, and once they have their tooth fillings removed the music broadcast stop

 

[K8MHZ]

There are times when the grounding system can act like an antenna.

Since it seems that this started a couple weeks ago, has anything been done to the grounding system that you know of? Has anything been done to the plumbing that may have been part of the grounding system?

If a quick look doesn't provide a solution, you are going to have to get more info.

If you can make the music intelligible and it is a radio station, listen for a station ID. That will tell you how close they are.

Also, since this is an apartment, there may be some device in another apartment that is causing the problem.

Be careful about implementing solutions that involve modifying or adding anything to people's stuff. That may put you in a liability loop if something ever happens to that device, your fault or not.

 

[hurk27]

Use the "receiver" side of a telephone toner set, its nothing but an audio amp and a pickup coil through an AM detection diode, by placing it near conductors and metal you should hear this station and be able to hear a call sign, you can input the call sign into Google Earths search function and it should show you where the transmitter is, it might be out of sight from your location, but if it is a ganged array pointed in the direction of this house, you will get RFI from it, I have a couple neighborhoods that get lam blasted by a AM Spanish station that only putting out 25kw day and 5kw night, but it will even stop a Genie garage door opener, as the digital interlink to the eyes can't communicate till I put RF filters on the lines, about every house has RFI filters on the phone lines and data cables, and those with the Genie GDO's, depending upon the strength of the RF it can be a bare to overcome.

WLS AM in Chicago had bad time with a new neighborhood that was built under their 50kw or 100kw transmitter back a few years ago, they even had florescent lights lighting up, I never heard the outcome of that one.

 

[G._S._Ohm]

there is a humming sound coming from all the apliances when they power them up.

Sine waves make a "hum". Square waves or 60 Hz harmonics make a "buzz". Check your power waveform.