Back in HVAC discussing noisy variable speed fans. Looking at CB and amateur 10/11 meter bands. I have to turn ac off to get good noise levels. Turned cb on yesterday. New noise. Sssss pow. Sssss pow. Constant interval , S3 level. Take portable cb around house. Strange places where it showed up, with no sensible answers. Go outside, getting stronger near poles. Walk up street, getting stronger. Top of hill, 300 feet from house, signal stronger.
Go back to house, thinking I still have problem in house. Start shutting off breakers. Got it. Goes to kitchen/ dinning area. Start pulling plugs. Look on breaker chart. One more near laptop area. Look down at sears lithium battery charger, no battery inserted. Pull plug. No noise. Question is, I'll have to go back up the street and check. Neighbors may also have similar devices.
Greg