I am going to try and answer the OP's question.
I agree with some of the other posters in this thread... If you want a great CONVENTIONAL scanner, you can't beat /\/\otorola.
Trunking system? That's where it gets dicey. When you program a Motorola radio to a TRS (You can NOT just buy the software and do it, you need a system key, although it is possible to hack the radio so you don't need it), every time you begin monitoring that TRS, something called affiliation takes place. Affiliation occurs when the radio transmits a data burst to the trunking controller and basically says this: "Hi, system! I'm a Motorola Radio, and I would like to use your system now, please." The TRS Controller says, "That's great! What would you like to hear?" and so on. There are two things wrong with this:
1. You violated federal law by transmitting that affiliation burst on PUBLIC SAFETY frequencies.
2. Because your radio has affiliated, the system admin will see that it is there. If he is worth his salt, he will assume you are an unauthorized user. He will then instruct the TRS controller to send a "Kill" command to your radio. This permanently disables the radio forever, turning it into a brick.
(Notes: It's possible to disable affiliation, but it will only work on some systems under the right conditions. It's better not to try. Also, there are two ways to unbrick a radio: have the sysadmin unkill it, which they won't do, or send it to Motorola, where you run the risk of not getting it back.)
The moral of the story? Don't do it.
BTW, auxscan, the systems saber and the ASTRO saber are capable of trunking.
