can't hear talkgroups

Hi So, I been listening to the cottonwood heights Police Dept, And I notice they have dispatch, and car to car, but not a tactical channel, I tried listening on other talk groups, but I don't hear anything when they talk. If anyone could help me I would be happy. Thanks! I just wanna be informed...

I'm just getting back into scanning after a 3 year hiatus (damaged my Pro 96 beyond repair and couldn't afford to replace). I just purchased a Pro 651 which , thus far, I am happy with. My issue stems from an isolated group of talk groups on a somewhat large system. The system is...