Sounds like a burglar alarm set-up that sends a message over the air when when a zone is tripped on the panel (B/A). I ran into these a long time ago when I worked in a Central Station (Alarm Co.)
Ward county (155.79) and Winker county (155.64) also have an automated voice like that at times. It usually will say something like what you said, or something about the radio system (like site 2 is down). Maybe they have voters or something!
These are some type of emegency alarms the S.O. has installed in one of the court rooms and some of the other offices. I have had to lock them out on my dps radio, they get very annoying when they get stuckk