understanding database/trunked systems

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alok

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I am new to this and hearing on a regular scanner radio ,unable to follow trunk systems.
I'm looking up Trunked Systems in my area in the database. I see RED frequencies in RED ,a mention of BLUE frequencies ,but see none in BLUE ( I understand that these are MAIN & ALTERNATE CONTROL FREQUECIES ) is this where I'd hear the constant data ?
I also see frequencies in BLACK ,are the frequencies in black the open frequencies where I'd hear the Trunked System communications on a regular radio but naturally unable to follow it ... these black frequencies being controlled by the frequency mentioned in RED ?

Am I understanding this correctly ?

Al
 

troymail

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I am new to this and hearing on a regular scanner radio ,unable to follow trunk systems.
I'm looking up Trunked Systems in my area in the database. I see RED frequencies in RED ,a mention of BLUE frequencies ,but see none in BLUE ( I understand that these are MAIN & ALTERNATE CONTROL FREQUECIES ) is this where I'd hear the constant data ?
I also see frequencies in BLACK ,are the frequencies in black the open frequencies where I'd hear the Trunked System communications on a regular radio but naturally unable to follow it ... these black frequencies being controlled by the frequency mentioned in RED ?

Am I understanding this correctly ?

Al
The data on the RR database listings is generally completely dependent upon and reflect what any given user submits.

Trunk systems CAN have primary (RED) and alternate (BLUE) control channels but if the user who submitted the information just doesn't know all of the information, they provide what they do know. Others can come along and make improvements to that information once it is known.

The control channel (data/signal) assigns radio users on the system a frequency when they want to talk.

A control channel will typically have constant data.

Note that traditionally, systems had a primary control channel and a few "alternates". However, it has been said that in reality, ANY of the system/site frequency could be used as a control channel. Some systems these days actually broadcast information that indicates exactly that (all are considered possible control channels).

As you said - you can enter the system/site frequencies and possibly hear voice but it ill be difficult to follow the conversations as the control channel/system assigns frequencies as the conversation(s) go on. At least one exception - P25 Phase 2 - you're not going to hear any conversations due to the nature of the signal.
 

GTR8000

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Note that traditionally, systems had a primary control channel and a few "alternates". However, it has been said that in reality, ANY of the system/site frequency could be used as a control channel. Some systems these days actually broadcast information that indicates exactly that (all are considered possible control channels).
Motorola ASTRO 25 (P25) systems can have up to four frequencies designated as control channels. They are known as "preferred" and "alternative", and generally do not rotate much at all (unlike how older SmartZone systems would rotate every 12 or 24 hours).

Other manufacturers, such as Harris, allow for more than four channels to be designated as control channels with their P25 systems.
 
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