Trunked Systems: Input frequencies?

[Ovencleaner]

Well I am trying to figure out input frequencies for a Motorolla Trunked Control Channel 800 MHZ style system.

Scanner Frequencies: Southeast Texas Area Radio Network (STARNET) Motorola Trunking System, Metro Houston area, Texas

I know the offset is -45 MHZ, but is that for primary control channels?

What exactly determines input frequency?

[Stealth Stalker]

Originally Posted by Ovencleaner

Well I am trying to figure out input frequencies for a Motorolla Trunked Control Channel 800 MHZ style system.

Offset is irrelevant. All you have to do is program in the frequencies that are in RED and BLUE on the list of control channels. You don't need the others at all.

What kind of scanner? If you're lucky, you got one that can be loaded by computer, making things a LOT simpler and faster, using pre-made files.

[Lucky225]

Stealth he's asking for INPUT freq's... assuming he means to key up/transmit? If not just the red & blue data is all you need to input and set to motorola or edacs mode depending on the system your area uses. If you trying to transmit -- good luck, trunked systems are data controlled and only authorized radio IDs can key up, and the freq for transmit is different every time and determined by the data channel, that's how trunk works, when a user goes to press the transmit key, the freq to key up on is 'known' by the trunked 2-way because it's constantly listening to the data stream, and the system that controls the data stream monitors the trunked network (which is a handful of frequencies) for what freq's ARE *NOT* being used and tells all the radios which freq to use when they go to key up. So instead of channels, the trunk system is just a few frequencies shared between a large group, and each agency has it's own "talkgroup ID" which seperates the communications on the network so only people monitoring that talkgroup hear calls on that talkgroup.

[Stealth Stalker]

Ooops, you're right. Sorry bout that. That's an extremely rare question in scanning circles, so I wasn't thinking about it.

The whole input monitoring theory of avoiding traffic cops is totally bogus in an urban area though. You are going to hear every Houston cop within five miles of you everytime they key up their radio for any purpose. And what you will NOT hear is any of them announcing that they are setting up a radar trap on the road you are travelling on. It simply doesn't work that way. The wide open rural highway and really small towns is about the only place that theory ever pans out. And even then, it's just a whole lot more trouble than it is worth.