Completely outside of my area of expertise, so this may be a silly question, but are police transmissions distinguishable from others in their encrypted form? If so, there could still be a use case for knowing _where_ the cops are. Wonder if some sort of mesh could be used to triangulate the positions of these signals.
I think the repeaters would block out any of the mobile radios. So you could see the dispatchers easily, but the individual mobile operators (EMS, Fire, Police) would be hard to distinguish.
If the mesh was every Digital TV tuner inside a municipality, then maybe the mesh could triangulate position.
Outside of my area as well, but, IIRC Kevin Mitnick wrote about using a radio set to encrypted frequencies. When he was out and about, if he heard traffic on those frequencies, then he knew the FBI etc. must be nearby.
