Find the control channel. Create a new P25 site / system in your radio with this one frequency. Set your radio monitor and Hold on this system with control data output option turned on.
Run Unitrunker for a while to accumulate additional information like voice channels and talkgroups.
How long should it take before UniTrunker will display the FREQ with other than 000.0000? I was mobile in another county for some time trying to do this one SAFE-T tower and all I ever got was about 5 channels with 000.000 which would display TG's as they talked. I stayed put in a parking lot until I seemed to attract to much interest from local LE's. When the LE's started showing up and circling my location, I felt it was time to pack up and leave the area.
BTW: The signal strength was 5 bars on the 996XT and 99% in UniTrunker where I was parked.