A buddy of mine called me with this so I thought that I would throw it out for comments. The problem is that he can hear a local AM radio station coming from at least two motors in his house. If the fridge fan or compressor [not sure which], or the space heater fan motor is running, he can hear the station; disconnect the appliance from power and the sound goes away. And he can hear it coming directly from the motor, with the audio clear enough that he can even recognize which DJ is on at the time. At first I assumed that this is related to something like an amplifier with a bad ground in the neighborhood, but I guess a motor could resonate electrically at just the right frequency, and then convert this to sound? Anyone who works with VFDs can verify that motors do convert electrical sine waves having a frequency ranging from 1-20Khz, to sound, very nicely. Also, it occurred to me that the wiring in buildings tends to resonate at about 100Khz - very near the bottom end of AM radio.