VERY broad banded, and effects all HF bands. Noticeable on ALL SDR's here at the QTH!

I have a hunch it may be a powerline insulator arcing due to the sound and width of QRM.
See the examples attached:
Note the spacing between gaps appears to be same (like a timed pulse), but it appear to be random. Will be silent for extended periods of time, then randomly appear and disappear.
Time to bust out the active loop and do some DF'ing!
73 Kriss KA1GJU