Wit's end with unknown source of RFI

No idea what that is. I'm out. But I've heard something similar also.

 

Just curious- has anyone tried turning off all of the lights except an incandescent flashlight? 20 Khz. might be a switch-mode power supply- common in LED systems including grow lights ( raising that funny herb? ) and most CFL ( mercury-vapor ) lamps. Neon signs can also have RFI-producing power supplies.

 

Could be coming from an electric fence at the Crystal Blue Ranch...

 

Over The Horizon Radar. I new model I believe. From Russia with love.

 

I was waiting for someone to give us the requisite "OTHR" answer.

 

I've seen security camera's, particularly an Axis Communications POE PTZ camera that had 100' run of cat6 cause an identical signal to this.

 

When everything in the house was turned off at the breaker, did you make sure that no battery powered or backed up devices were still operating?

 

Super simple to test. Not familiar with your SDR, I own a SPRPlay RSP2 and an Airspy HF+. Happens to me on both, although the SDR is chronic and more pronounced. You will know instantly if it will work or not. As you turn down the RF Gain the false signals (intermod), you wil notice on the spectrum the false signal fades.

The bad news if that is the problem, I do not know how to fix it other than RF Gain. It may not even be intermod on my units, I suspect the units just goes into oscilations. You should not need much RF Gain for HF. Even though it is an SDR Radio, it still operates like its analog cousin. Example say SSB. You would turn the AF Gain up, a long way up, then use RF Gain to control audio level like you would operate on a analog radio.

 

I do have an extensive IT system providing the household IT needs (and wants), and it is run on a UPS. But I powered that down as well. I even waited until the last capacitor in the last power supply was drained. There wasn't an electron moving in the entire AC grid.

 

Unfortunately it's not the SDR. These are not false signals, and I get them even with the SDR completely disconnected, and on rigs that are not SDR capable. It appears to be something in the 'hood'.