Before running any trunking decoder software, please follow these steps to validate the discriminator audio passed into your computer. You will need a program that can display the waveform like an oscilloscope.
This will take some research. Failing that you will have some hard work.
1. check the radio reference Database.
2. check government bureau for radio licenses
a. the license for the control channel frequency may have to voice channels.
3. hard search; scan up and down in the band occupied by the other frequencies.
a. This will take time and luck.