On 3/23/26 4:17 PM, Mark Graves wrote:

What does the audio component waveform look like? If line noise, it would most likely have 120 hz pulses well defined by some sort of arc on the positive and negative peaks. 

It has only 60 Hz and its harmonics. See attached. I have turned off everything in my shack and ran the radio on battery. It is still there. The distance from my antennas to the nearest neighbors is about 1000'. My house is about 700' from my shack & 160m antenna. So, whatever this is, it must be pretty strong source.

But now I know better what to look for and will setup portable 160m receive and perhaps a loop as Stan suggested.

Jussi (aa6kj)