Ok, I got my Volpmeter (awesome), and I’m checking all around my house. I find a point that with this device plugged in I get ~4.5V signal and .07 noise. That’s somewhat lower signal than other outlets. I remove that device and I get ~8V signal and .10 noise. (Yeah, I got a XTB-IIR).
Ok, I found a signal sucker. I get a little less noise when plugged-in (good), but nearly 1/2 the signal (bad).
But wait a minute … the device is a X10 Powerflash Module - WTF!?
I use this module to sense a DC level and send a X10 when the DC is present. I tried a second module, and removed the DC input in case there was some weird feed-thru. Same results.
Why would an X10 module act like a signal sucker on its own network? I can’t isolate the Powerflash Module with a filter because I need the X10 signal from the module to get through to the AC line.
Any thoughts?