There's a chance that I might be getting the thinest shred of signal from this one.
I have nothing by ear, and nothing on the spectrogram running normally, but I
DO have a trace of higher density on the waterfall right around that frequency if I slow down the display to sort of "accumulate" the readings into a more visible form. It's just barely there, and since I can't make it out by ear - even with headphones and filtering - I can't tell if it's a pulsed signal or a stray harmonic of something, but it
does move up and down the spectrum normally as I tune, so it's just possible that I may possibly be hearing the faintest trace of it.

location: upstate South Carolina
radio: Icom IC-718
antenna: 400-foot longwire @ 40 feet