Cambridge Police

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kjl13

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Hey everyone,

Does anyone know if Cambridge Police( that is on the Phase 2 commonwealth system has any patches to UHF and or VHF. Or is it only on the 800 MHz system?


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jmorrissey23

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Hey everyone,

Does anyone know if Cambridge Police( that is on the Phase 2 commonwealth system has any patches to UHF and or VHF. Or is it only on the 800 MHz system?


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Cambridge Police's Main Channel (Ch.1) is patched to 470.3125 CTCSS 131.8 and there backup channel (Ch.16) is patched to 470.1250 CTCSS 127.3
 

garys

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To clarify. Cambridge is NOT on the "Phase 2 Commonwealth system." They are on their own Phase 1 system that shares ONLY the Astro Core 7.1 (or whatever the latest revision is) controller that is owned by the state. That's a subtle, but important distinction.

Both RR and the Wiki at Scan-NE are not entirely clear on this. The CONTROLLER is owned by the state and the other trunk systems (Cambridge, Worcester, MassPort) use that controller.

Cambridge Fire has simulcasts Ch1 of the trunk system on 471.3125 for mutual aid purposes.
 

kjl13

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So Cambridge has nothing to do with the CoMIRS system? And do they have their own site?
 

garys

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Not "nothing" as they share the trunking controller. The radio hardware is theirs, not the states. The system is not set up like, say Rhode Island where the state owns the system and allows municipalities to buy into it. Which is where the confusion comes in.

The main area of commonality is coordination of the Talk Groups so that there is no overlap of numbers. That allows individual radios to use any site if the need arises.

For example, MassPort units often access the 700 Mhz Overlay if they can't reach the MassPort system. You'll see that for units that work downtown at MassPort facilities. MassPort PD Ch 1 will appear on the MassPort trunk and the 700 Mhz system because some of the units not in East Boston have better signal into the 700Mhz system.

At some point the various systems might operate as one, but I have no idea if there are plans around to do that.

So Cambridge has nothing to do with the CoMIRS system? And do they have their own site?
 

kjl13

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Not "nothing" as they share the trunking controller. The radio hardware is theirs, not the states. The system is not set up like, say Rhode Island where the state owns the system and allows municipalities to buy into it. Which is where the confusion comes in.

The main area of commonality is coordination of the Talk Groups so that there is no overlap of numbers. That allows individual radios to use any site if the need arises.

For example, MassPort units often access the 700 Mhz Overlay if they can't reach the MassPort system. You'll see that for units that work downtown at MassPort facilities. MassPort PD Ch 1 will appear on the MassPort trunk and the 700 Mhz system because some of the units not in East Boston have better signal into the 700Mhz system.

At some point the various systems might operate as one, but I have no idea if there are plans around to do that.

That makes much more sense, thanks for the explanation.

So if another town wanted to go on the system they would need to have a site nearby and also buy the radio equipment? Then just get it authorized by the state?
 

garys

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It would likely work the other way. They'd request to use the controller and when that was approved, they'd buy their own hardware. They'd be responsible for building the infrastructure and maintaining it.

That's my understanding of how it works.

Zone 1 on the analog system and the 700Mhz Overlay are a bit different. Boston and the state share responsibility for both is my understanding.

At one time, the City of Boston had it's own 800Mhz analog system. Back around 2007 or so, they merged that system with the MSP system and it's now shared. Or was at least. The people I knew from Boston who did that stuff are all retired, so I don't know the exact details of the current system. Zone 1 carries all of the City of Boston users and some state users, but not MSP. The 700 Mhz Overlay has the same users simulcast for the most part.

That makes much more sense, thanks for the explanation.

So if another town wanted to go on the system they would need to have a site nearby and also buy the radio equipment? Then just get it authorized by the state?
 

kjl13

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It would likely work the other way. They'd request to use the controller and when that was approved, they'd buy their own hardware. They'd be responsible for building the infrastructure and maintaining it.

That's my understanding of how it works.

Zone 1 on the analog system and the 700Mhz Overlay are a bit different. Boston and the state share responsibility for both is my understanding.

At one time, the City of Boston had it's own 800Mhz analog system. Back around 2007 or so, they merged that system with the MSP system and it's now shared. Or was at least. The people I knew from Boston who did that stuff are all retired, so I don't know the exact details of the current system. Zone 1 carries all of the City of Boston users and some state users, but not MSP. The 700 Mhz Overlay has the same users simulcast for the most part.

Ok. Thanks for the information, learned a lot more about the system.

Do you know if they have plans to expand so they can completely switch over to the new system, moving away from the phase 1 system.


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GTR8000

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To clarify. Cambridge is NOT on the "Phase 2 Commonwealth system." They are on their own Phase 1 system that shares ONLY the Astro Core 7.1 (or whatever the latest revision is) controller that is owned by the state. That's a subtle, but important distinction.

Both RR and the Wiki at Scan-NE are not entirely clear on this. The CONTROLLER is owned by the state and the other trunk systems (Cambridge, Worcester, MassPort) use that controller.
Actually, they are the same system if they share the ASTRO 25 core (and thus SysID/WACN). The core would need to be at System Release 7.11 or newer for Phase II TDMA.

What you meant to say is that they have their own site on the D14 system.

Further, I see that both Cambridge and the Metro Boston cells are RFSS 2, which means they operate on a separate zone controller than the sites in RFSS 1. So all RFSS (Zone) 1 sites are operating off of one zone controller, and all RFSS (Zone) 2 sites a separate zone controller. Both are connected to the same system core, however.
 

kjl13

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Actually, they are the same system if they share the ASTRO 25 core (and thus SysID/WACN). The core would need to be at System Release 7.11 or newer for Phase II TDMA.

What you meant to say is that they have their own site on the D14 system.

Further, I see that both Cambridge and the Metro Boston cells are RFSS 2, which means they operate on a separate zone controller than the sites in RFSS 1. So all RFSS (Zone) 1 sites are operating off of one zone controller, and all RFSS (Zone) 2 sites a separate zone controller. Both are connected to the same system core, however.

Hmm. Ok


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