Interference disappears after 20 sec. power outage

[Uncle John]

I've had a "interference" (qrm) problem for a few weeks. The "noise" is/was a rapid pulse every 1/2 second though varied slightly, noise didn't sound significantly different in am, u/lsb, cw, rtty modes, pulse resonates/appears specifically on 930, 1200 & 1600 am. , & (of course) 6.920 through 6.945 mhz. though variable, & signal appeared on various sw frequ.'s. This last Wednesday I did a bit of amateur detective work hoping to isolate origin. Here are my results: The interference seemed to be strongest when I held my Panasonic Model R-1240 am radio nearest to next door neighbor's circuit breaker panel board, located outside behind my bedroom, along with 4 other panel boards.
Last night there was a 20 second power outage (wind storm) &..."Praise the Propagation Gods" (just to be on the safe side), the @#$%**& interference disappeared. So far. Any thoughts? I'm not that technically experienced so will appreciate insights from fellow board members. Thanks. Uncle John.

[The Poet]

I don't know....

But maybe I need to throw the main switch here, or at my neighbor's....

[Uncle John]

Interference is a four letter word