Cobb County Digital

[ButchGone]

If I were traveling through Cobb County and wanted to hear the new digital system for police, do I monitor the Cobb County frequenices or program in the GEWIN state system? It seems like the 9 freqs listed for just the Cobb County system won't be enough to accomodate full migration of all services?
It's a little confusing when you look at the GEWIN system. Do Cobb Police talkgroups pop up on both systems?
Thanks.
BG

 

[Thunderbolt]

Do Cobb Police talkgroups pop up on both systems?

Yes they do, especially if they can't make it into their own site, but are in range of the Atlanta GEWIN site.

73's

Ron

 

[ButchGone]

Re:

Thanks Ron! So, in order to monitor Cobb County Police I will have to monitor two trunked systems instead of just one? Will this be the case when DeKalb County and others upgrade to digital?
Again, thanks for your help.
BG

 

[Casey]

Program just the Gewin control channels on the cobb site on the Gewin page and you will get the county police. If you stick with the cobb analog control channels you will hear the fire departments and most of the cities. By the way, depending upon when you swing through you may still hear the county police patched on the analog system on their old talkgroups. You do not have to program in the state-owned simulcast on the Gewin page at all. That system is pretty silent so far.

 

[Thunderbolt]

Thanks Ron! So, in order to monitor Cobb County Police I will have to monitor two trunked systems instead of just one?

Yes, in reality they all apart of one trunked system but with different simulcast sites. When the user has their radio on, it will affiliate with the tower/system closest to them. This means that if a Cobb County Sheriff unit was in Atlanta, you would hear him off the State system, as well as all the other traffic on that talkgroup. Likewise, if another patrol unit(s) were on the same talkgroup, but in Cobb County you would hear all the radio traffic on that talkgroup on both sites. However, since the Cobb County system has such great coverage, you will probably only rarely hear them on the State site, so you can mostly scan the former site and not miss much of anything.

Will this be the case when DeKalb County and others upgrade to digital?

Yes. I have not heard anything new on DeKalb County, but the last I heard they plan on joining the GEWIN TRS, and they are researching the funding and procurement of real estate to erect towers at this time. However, to the best of my knowledge, no construction has started at this point.

Dekalb County would become another simulcast system, with several towers all across the county. They would also connect via high-speed microwave to the Cobb County and State sites, to connect with the main site-controller, which is the master brain of the network. Further, the controller acts as a switching network and recognizes each radio and allows it to roam from one site to another, much like a cellphone network does.

Eventually, since Forsyth County is operating the same system technology as GEWIN, they maybe integrated into the system down the road. Ironically, everyone was hoping that Cherokee County would join GEWIN in the future, but they decided to go with M/A-COM instead. However, other counties in the Metro Atlanta area are taking a more serious look at GEWIN, rather than other vendors, but in the final run, governmental agencies tend to look at the bottom line when it comes to how much money will spent.

73's

Ron

 

[ButchGone]

Re:

Thanks again Ron!
I understand now how officers from Cobb can roam seamlessly out of their county. But with Cherokee on the north side of Cobb going MA/COM as you mentioned, what does this mean for interops? For example, a Cobb Sheriff's unit goes north on I-75, does his radio quit working when he's out of range of the Cobb towers, or can Cherokees' MA/COM system hear him and work him through their system to Cherokee deputies? If not, it makes no sense for counties to spend mega-millions on a system that's not compatible with most users in the state (Motorola P25). If there's no interops, then why migrate away from analog VHF when that already works statewide?
...BG

 

[Thunderbolt]

Thanks again Ron!...
But with Cherokee on the north side of Cobb going MA/COM as you mentioned, what does this mean for interops? For example, a Cobb Sheriff's unit goes north on I-75, does his radio quit working when he's out of range of the Cobb towers, or can Cherokees' MA/COM system hear him and work him through their system to Cherokee deputies?

As I understand it, M/A-COM plans on have several talkgroups patched together between the two systems. This method will allow rather limited interoperability options, but will work only if the Cobb County unit is in range of a GEWIN tower site. However, they can switchover to the nationwide I-CALL/I-TAC channels, which are conventional analog frequencies and communicate that way.

As more GEWIN sites are added or as more counties decide to integrate into it, this will expand the range of any mobile and portable radios to communicate back to their home area. For instance, LaGrange City/Troup County plans on upgrading their trunked radio system in the future to probably include the city of Columbus, Muscogee and Harris Counties. If they decide to upgrade and become part of the GEWIN TRS, that would extend Cobb County's coverage to those counties, so they could talk back to their home base or communicate effectively with the local units in those areas, if there was a wide-scale disaster that needed additional support from other agencies from around the state.

73's

Ron

 

[b7spectra]

Looks like Cobb has ceased the simulcasting. My Spectra was dead all day on CCPD!

 

[codeplug]

Any updates on the Cobb County TRS 800 System lately.
I checked the FCC DB and it looks like a lot of the frequencies have been changed over to Digital Voice & Data use
but several freq.'s.are still listed for Analog use.
Emission Designators: 16K0F3E, 16K0F1D, 16K0F1E

 

[b7spectra]

The old analog is still out there, you might even find a control channel up. Anything on it? Nope!

 

[MTS2000des]

about this time last year, we used the analog TRS for a special event with Cobb STEP. It was still up. After Thanksgiving, it was gone, apparently one of the Kennesaw mountain sites was still up, in failsoft for weeks- last I checked it is completely off the air.

The official memo that CC911 sent out to mutual aid agencies is they would support the system until 2010. but everyone was off of it before this, IIRC the city of Marietta was the last to go in the summer of 2008.

 

[codeplug]

Thanks for the update.