I've been able to listen to this system on a few occasions. I just hooked up an AC-powered amp and I can now receive it at home, zero signal to 3 bars now . Heard a good bit of activity this afternoon.
Logged one new TG  and an I-call [710584-710396] so far today. 659 sounds like base maintenance (dealing with air handlers and lighting). In addition to these and what Mike posted I have:
610 and 654 sound like they could be PD.
Add 611 to the list of TGs.
2/6/07 TG650 sounded like it could be a Frederick Co FD Dispatch patch