Here's a weird noise that is on almost all the time - peaks 77kHz apart at -80dBm from the broadcast band to 30MHz.
Two spectrum displays, the upper is zoomed in, lower zoomed out. https://www.dropbox.com/s/0zqbgtvl80noe02/noise%20every%2077%20KHz.JPG
Frustrating... goes away sometimes on no apparent schedule, not it my house, but I'm in an urban environment.
Ideas before I call the power company?
Thanks and 73,
It is VERY local to you. The only signal sources that would have such uniform strength all the way to 20MHz have to be within a wavelength of your antenna. And, those frequencies are way too high to be propagated in through the power line.
Cell phone chargers can do that
Cable/FiOS modems and routers, and their power supplies
The SMPS in any electronic appliance in your home (not all SMPSes vary in frequency, some actually use crystal controlled clocks)
The SMPSes inside the devices themselves (modern consumer devices all have them)
Don't forget your ham gear: any radio that can handle a negative-going ALC signal from an amplifier has an SMPS inside to generate that negative voltage. I can sometimes hear those SMPSes on the receiver they're part of.
Turn off ALL battery operated devices in your home by removing the battery. You cannot assume they're off until the battery is removed.
Operate your receiver from a battery.
Start turning off breakers in the house, looking for a change.
I once had a coffee pot generate hash like that - and it was only "barely" electronic, in that it had a clock so you could set a morning brew time.
I haven't scoped it out yet, but at my present QTH, I do suspect something outside the house. The power pole out front has a cable TV box on it and it emits a very audible acoustic buzz...no doubt there are SMPSes in that thing.
GL ES 73,