As I understand it, the only transmissions you will hear broadcast on the frequencies at the Coweta County tower sites will only be on the talkgroups authorized to do so and these are strictly talkgroups assigned to Coweta County and Newnan with the exception of a few mutual aid or common talkgroups. The system would busy out quite frequently if all of the talkgroups used by the agencies in Carroll, Coweta, Haralson and Heard Counties were set up to simulcast at all sites at the same time across all four counties. Therefore, to prevent this from happening each talkgroup and individual radio must be authorized to "roam" to the other tower sites based on system and individual radio programming. In order for the system to be able to simulcast each talkgroup used by each agency at every tower site the system would have to be designed to have every frequency at every tower site throughout all four counties and this would be extremely expensive to do and maintain, so I don't think this is the case. Anyone on RR familiar with the actual system design or have a working knowledge of it that can confirm this?
If the system is designed the way I think it is, it will not enable someone in Coweta County to hear radio traffic occurring in Carroll County any better regardless of whether the two systems are tied together or not.
That is correct. The Smartzone OmniLink zone controller allows for specific load balancing site and individual ID provisioning, roaming to specific zones/sites can be enabled/disabled for specific talkgroups and specific radios. It all depends on how the system management wants it, and available resources at each site.
In large statewide systems, unlimited roaming has proven to be a bad omen. The bridge collapse in Minnesota a couple of years ago proved this, when low density sites on the ARMER system became overloaded with distant talkgroup traffic by local users "wanting to listen" to the incident from hundreds of miles away. The smaller sites had very few channels, some as little as 3-5, and easily became busied out so local talkgroup users could not get radio resources to complete calls.
In another incident in Colerain, OH, two LODD's occured and later forensic examination of their Smartzone Omnilink P25 radio system traffic showed many affiliations and de-affiliations by users across multiple zones, all occuring simultaneously which caused several transmissions from the fallen firefighters at the scene to be blocked. A great majority of these affiliations and accidental inadvertent keyups on the talkgroup were from radio system users who were not involved or part of the incident response.
In Metro Atlanta, the Cobb DTRS has some talkgroup roaming capability on the UASI overlay for authorized users. One of the reasons the UASI overlay is underused (aside from high per radio user fees) is the lack of radio resources (RF channels) at each site to support heavy use for day to day agency operations.
So, in Coweta, you'll only hear traffic on the other county talkgroups when an authorized users' radio affiliates on one of those talkgroups on those distant sites. When they leave the coverage area, their radio will re-register on their "home" WACN and those talkgroups will again go quiet on the distant sites.
