What scanner do you have? You can also use Pro96com to decode the control channel from the some scanners and log the talkgroups on each site. Other software can be used as well. Proscan comes to mind for uniden scanners.
See here for list of scanners with control channel output for pro96com. Pro96Com - Control channel decoder for P25 Trunked Radio Systems
See here for list of scanners with control channel output for pro96com. Pro96Com - Control channel decoder for P25 Trunked Radio Systems
