Last night, near Pellston, MI, I heard a Classical Religious recording on 630. I assume it was KYFI (KXOK).
Strange conditions suggesting some Auroral or Meteor Shower effects. It was very cold, below 0 to just above 0, and I was hearing enhanced ground waves during the Daytime, with WJML 1110 at 11.5 mV/m and WTCM 580 at 7 mV/m, around twice their Summer readings on the FIM-41. The snow may be a factor, but the big variations seem to be the extreme cold.
WMFN 640 was heard around the same time as KYFI 630, and WIND 560, which probably could have been heard except for CFOS Owen Sound, ON and the noise level during the Daytime. Bumpers for all Night Talk Shows heard all over the dial, one in the background under a stronger signal. Have to look through the show affiliates.