As I understand it our local law enforcemant and fire department use a LTR system. When I think of a trunking system I think of 5 or 6 different frequencies with the radio having the capability to skip to the one not in use. But when listening to my scanner I hear all of the organizations using only one frequency, with the exception of a scrambled frequency that gets used very seldom by the SO and is shared with the city water dept. Often times while I'm monitoring I will hear a dispatcher in the background talking to another officer. I have done a search on all the frequencies being used by our local government, but never here them on any other frequency. I have all the frequencies punched in on my scanner and you can hear them make a short transmission (not voice) which I've read is typical of a LTR system. I have also heard them say go to tac, when they do I search all the frequencies I have stored and can't hear anything, but when they say go to ch. 4, I know that means they are going to use the frequency in which they scramble on. Can someone shed some light on the subject. Thanks.