Originally Posted by xbi0s
Encrypted and trunked systems are not the same. Trunked systems have been around a while, and can still be analog-based.....as opposed to some of the articles up on that site you linked to talking about more and more local rescue units switching over to digital technologies...and in some cases encrytped digital radios.
From what I've seen most scanners now have the ability to listen to a analog trunked system....there's basically just a "control" channel that the scanner listens to that tells it what "channel" (frequency) to switch to to follow a conversation.
Scanner listening is just another hobby and as an amateur radio operator I've played around with scanners and have enjoyed listening to the local rescue units, or tracking down who's on what frequency, or listening to the airport tower, etc....
And I believe it's up to the state as to whether it's legal or not, so check your state's statutes or ask around.