Electric lines broadcasting AM radio

How are the electric lines in my neighborhood ruining AM reception? Aren’t they pulsing at 60Hz? How are they interfering with my reception at 640kHz?

The phenomenon is called “carrier current” and it’s (or was) common on college campuses as an efficient way to operate a radio station without the hassles of getting an FCC license. It’s also used by community stations.

Carrier current uses the electric wiring to transmit the radio signal. It’s not especially powerful, so whatever you’re hearing has to be close. And unless the power company has special equipment installed, the signal can’t cross transformers.

If you can, listen to find out what the station is broadcasting and report back. If it’s a legit station, let 'em know you’re listening. They’ll appreciate it. :slight_smile:

But your radio isn’t broken, trust me.


I’m not hearing another station, there’s just a lot of static if you’re on that side of the road. I assume that it’s from the normal function of the wires.

It could just be interference from antennas or poorly-shielded equipment. It happens.


Lots of devices put high frequency hash on the AC lines. Brushed motors and anything that makes sparks (like welders) are pretty bad, but even things like lamp dimmers and poorly designed (or defective) computer power supplies can generate a fair amount of RF.

Power lines produce a magnetic field that can play hob with anything nearby, and AM radio is notorious for being sensitive to “interference”. In an audio recording workshop I attended I learned that the easiest way to check for electrical interference at a remote production site was to check the area where you planned to set up your equipment was with a cheap AM radio.

I vaguely recall from electricity class the story of a farmer who had a high-tension line running across his property. If he tried to drive his tractor under it, the tractor would conk out. (Which led us to realize that one could put a coil under such a line and it would effectively become the secondary winding of a transformer [the power line being the primary]. Voila: free electricity. Of course, you should not try this at home unless you want to be prosecuted for theft. . . .)