Originally posted by: Mark R
Over here, all the cops use encrypted digital trunked radios. No way to listen to that.
There's three different trunking systems, all of which can be listened to with certain scanners. If they go one step further and add encryption, then without the keys you won't be able to listen in. Our local police use an encrypted setup for some things, public frequencies for the rest.
Older scanners from Radioshack did 40-2400mhz without stopping, and some had a handy feature of locking onto a strong (local) signal and telling you what frequency it was. So if you didn't have it programmed in you could still listen to it and then program it easily. They haven't sold them in 10+ years though, since it's now illegal to listen to certain frequencies (Cellular, military, aircraft).
I guarantee you can still find them though, check the local Hamheads, Ham shows, stuff like that. If you ask in the right way they'll let you know what you can and can't do.