You could try listening on the repeater input. Some you'll hear loud and clear while others will be inaudible. I don't know if the input is listed here on RR.com or not. If you're in LV city, check out out the MERS relay on the Fort Leavenworth military digital system. There is one, I think, but I can't remember the TG. Nor do I know if it's always turned on.
Otherwise, buy a little 3 element beam. I get 'em very well with a discone. And jbxfire is right. Different scanners yield different results. . . .
Bob, wOnxn