Montgomery County P25 Metro tunnel testing

[dmi]

1200 EDT/
Radio Techs - MC Services 86 (id 28086) and 88 (id 28088) performing radio tests from Tenley Town up towards Grosvenor on:

17712

453

D

C11 CCVTAC1

C11 Chevy Chase Village Police Tactical 1

 

[ResQguy]

I assure you that was not P25 testing. What with there not being a P25 system and all.

 

[dwlipp]

I assure you that was not P25 testing. What with there not being a P25 system and all

Mostly true. The system is operating using an Astro 25 core connected to the Smartzone 3.0 system via SmartX currently, so there are some P25 bits in the picture right now, just not any of the RF site equipment yet; the RF bits should be on the air county-wide in less than a year.

 

[maus92]

Mostly true. The system is operating using an Astro 25 core connected to the Smartzone 3.0 system via SmartX currently, so there are some P25 bits in the picture right now, just not any of the RF site equipment yet; the RF bits should be on the air county-wide in less than a year.

I'm curious - does each tower site require a SmartX Site Converter, or is it installed per simulcast site (Montgomery County being technically a single simulcast site for the entire county.) Are the Metro tunnels considered a seperate site?

I believe Howard County also upgraded to an Astro P25 core, but remains a SmartZone system.

 

[dmi]

Mostly true. The system is operating using an Astro 25 core connected to the Smartzone 3.0 system via SmartX currently, so there are some P25 bits in the picture right now, just not any of the RF site equipment yet; the RF bits should be on the air county-wide in less than a year.

IF not P25 then what? RR says:

System Type:	Motorola Type II SmartZone
System Voice:	Analog and APCO-25 Common Air Interface

So are you saying not a pure P25 system?

 

[maus92]

IF not P25 then what? RR says:

System Type:	Motorola Type II SmartZone
System Voice:	Analog and APCO-25 Common Air Interface

So are you saying not a pure P25 system?

That is what he is saying. The core is now Astro 25 (fully P25 compliant, with Motorola proprietary features / options), but requires SmartX to bridge to the legacy Smartzone system (some P25 features, i.e. the voice codec, but proprietary signaling) that the county currently operates.

 

[dwlipp]

I'm curious - does each tower site require a SmartX Site Converter, or is it installed per simulcast site (Montgomery County being technically a single simulcast site for the entire county.) Are the Metro tunnels considered a seperate site?

As you note, the County is a single simulcast site (zone) so there is one active SmartX. Unlike the Prince George's system where the tunnel coverage is provided by additional system sites, the Montgomery County METRO tunnel coverage is provided by over the air BDAs connected to the METRO DAS so there is no SmartX converter associated with our METRO coverage.

 

[riveter]

I'm curious - does each tower site require a SmartX Site Converter, or is it installed per simulcast site (Montgomery County being technically a single simulcast site for the entire county.) Are the Metro tunnels considered a seperate site?

I believe Howard County also upgraded to an Astro P25 core, but remains a SmartZone system.

SmartX is the simulcast site as far as the P25 system architecture is concerned. It sees that as the actual site. SmartX is also the 3.x zone controller as far as the 6809 simulcast site under it is concerned. It translates all the information from the simulcast site up to the P25 zone core, and translates the core traffic down to the signalling the 6809 simulcast site expects, working as a double imposter. One is needed per standalone or simulcast site.