Just a couple of quickies before I board my flight home.
While driving in to Providence this morning, I caught what sure sounded like MotoTRBO digital on 173.9875 MHz. The signal was moderate but not real strong as I entered the airport area (KPVD). The frequency has been associated with a number of agencies in the past, including FBI, DoD, FAA, USFS and the Department of the Interior.
Oh, and the TSA at PVD is using 172.9000 MHz, 162.2 pl in analog with voice inversion for the checkpoint screeners. Normal TSA ops continue on 172.9000 MHz, NAC 001.
I think the new TSA radio rollout is pretty much everywhere, so the only remaining mystery is a channel plan and PL tones for the different airports. And I have confirmed that the radios are using simple voice inversion, no rolling-code encryption.