Are you sure it was coming through on the trunked system? Don't recall them having any trunked analog capability. I know they have some non-trunked analog systems like ICALL/ITAC or CSPERN? Maybe that is what you heard. What were they talking about?
Troop E you say? Funny you should mention that... a few weeks ago I heard them on the trunked system and they absolutely *sounded* like an analog frequency. Much different than all the other talkgroups. Don't know what it means.
I have picked up some analog stuff on the CSP system as well, Off of the 868.3375 Control channel, Usually on CSP Channel 37, and 38. Must be some nearby system that uses the same control channel and some similar TG ID's.