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05-03-2008, 02:31 PM #1
- Join Date
- Dec 2007
I never understood what a trunked system was.
Someone tried to explain it to me, but as I took it, it was a bunch of frequencies put into one, and when someone talked on one of the grouped frequencies, it would be broadcasted.
I believed this for about a week, but I've come to the realization that it's just not correct xD.
What exactly is a trunked system, and how does it work?
05-03-2008, 04:36 PM #2
Re: Trunked Systems
A trunked system is controlled by a computer.
It has a number of frequencies that it can assign to a particular transmission.
Channels within a trunked system do not denote different frequencies but what are called Talk Groups and any one conversation can take place on any of the given frequencies, except the Control Frequency.
To scan a Trunked system the scanner constantly scans the 10 or so frequencies that make up the system but only stops on a frequency if the transmission is carrying the talk groups information you have requested to hear. So lets say you want to hear Port Washington PD, you would program in the Nassau County Trunked System frequencies and search for Talk group 04-083 - Port Washington PD. Of the frequencies you scan the scanner knows to only stop when the signal is identified by talk group 04-083.
When a user keys up the mic the computer randomly assigns an open frequency of the ones available in the system, in none are available the radio is "bonked". If it gets through that talk group begins to transmit and all other radios set to that talk group stop scanning on the randomly assigned frequency and start to recieve. Any response to the initial transmission can happen on any of the frequenciesavailable and is not necessarily the same as the one assigned to the initial transmission.
These are Nassau County's Trunked Frequencies as per LI Scanning:
866.1875 - Trunked System (1)
866.3375 - Trunked System (2)
866.5875 - Trunked System (3)
866.7375 - Trunked System (4)
866.8375 - Trunked System (5)
866.900 - Trunked System (6)
867.1125 - Trunked System (7)
867.175 - Trunked System (8)
867.900 - Trunked System (9)
868.175 - Trunked System (10 - Control)
868.425 - Trunked System (11)
868.575 - Trunked System (12)
868.725 - Trunked System (13)
868.650 - Trunked System (14)
I think thats about it...
Last edited by EMSJEEP; 05-03-2008 at 04:41 PM.
05-04-2008, 11:56 PM #3
Re: Trunked Systems
this link might help also.
The Difference Between Trunked and Conventional Radio Systems | Daryl Jones' Weblog
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