I get the impression that a lot (if not most) public service radio comm's (e.g. police, fire, ambulance, utility etc etc ....) in the USA is still analogue, not digital - is this correct guys?
UK police radio comm's have over the last 5 years or so been subject to the largest overhaul ever carried out: TETRA forms the basis to most public service radio comm's in the UK now, allowing various services (police, ambulance, fire etc ...) to link to each other nationwide.
Though there have been (and still are) problems with the system, one thing that has been achieved is the shutting out of hobby scanners/listeners.
TETRA demodulation is relatively straightforward to carry out, but real-time decyphering (and most Police TETRA com's are cyphered) has yet to be demonstrated. It's proved to be a pretty secure and reliable system.
The few police TETRA hand-sets that have been lost or stolen are quickly "isolated" and/or remotely deactivated.