I turned on AM640 early Wednesday morning, to discover I couldn't hear them very well. I had to turn up the volume fairly high just to be able to make out what Greg Brady was saying. It sounds like they may be on a lower power - although not low enough for good DX-ing. 

Not sure why, but hope it doesn't last. I'm an inveterate channel changer, and going from one station to another is tough when everyone else is louder.