I think I found the source of RFI in my apartment

[wa2ise]

For the past year or more, a persistent intermittent (half second brittz every few tens of seconds) burst of RFI that would pollute the MW AM band was happening. Took a while to track down. Thought maybe a bad thermostat in the electric water heater, turn its breaker off, not it, still hear it. Try other breakers, seems one breaker cycling makes it go away for about 20 minutes. I eventually find that it's the power supply charger for my laptop. Seems when the laptop blanks its screen (screensaver and powersaver mode) it makes the RFI noise. Tickling the laptop mouse makes the screen light up and the RFI goes away. Or if I unplug either end of the power supply (120V side or the 19VDC output side). Okay, need to filter the power supply charger. I have a couple of those Cornell Doublieer powerline RFI filters (small metal box with 3 prong power plug and socket and RFI filter inside, and that looks to quiet the RFI down to almost nothing.

And for the longest time I figured it was faulty electrical wiring in the apartment building. I could see the lights flicker ever so slightly when the RFI bursts happened. That power supply must have been sucking down much amperage for brief periods of time. The filter is rated for 3 amps, but that's continuous. So I don't think it will get blown out...