Im scanning the South Dakota digital system, (smartzone type II). In one city I can receive all traffic with no problem, but while im in a different city in the southern part of the state I can hear nothing. I can almost see the nearest tower site from my apartment, and scan 3 other towers that are close. Sometimes I see a talkgroup come up on the scanner, but hear no audio with it. BUT I know that there is traffic there because I hear it online. Im baffled, cant think of anything, any help would be great.