Jlanfn wrote:...Even if the entire county had been covered with one enormous simulcast system (pointless because you don't need to hear all the metro valley traffic if you're in Barstow), it would still be limited to 27 talk paths with one control channel. That is just enough capacity for portions of the valley area as it is (see System 6/7).
The newer systems are still limited by similar constraints. The number of channels is higher, as is the number of sites, but there are still limitations. In addition, there are practical limits on how many channels can be installed in a given site... there are physical space and power considerations, and other technical factors that come into play. But the big one will be frequencies. Not every frequency can be licensed at every site, so that can make large wide area simulcast systems almost impossible to build. So, it gets broken down to separate systems service a specific area, with channel capacity to match the requirements.
So, the new system will still be broken out into numerous smaller systems, like what's done today. It won't be as if you can program in one single system in your scanner and go anywhere in the county and hear everything.
Jlanfn wrote:So basically, the county needed multiple systems because that was the only way for the trunking technology of the time to provide the needed capacity and geographical coverage.
The mountain area needs are different from that of the valley, so there will be separate systems. What's different is how the multiple separate systems work together for wide area coverage for the users that are authorized for it. At some level, it will be one big system, but from a traffic and control channel aspect, it will be multiple systems just like it is today.
There can be specific users that are only authorized for a single site, for example jail units using a cell located at a detention center. Those guys may not be able to take their radio outside that site's coverage and talk to anyone. For other units, they may have seamless county wide coverage, and as it hands off from one cell or system to another, the user can be almost completely oblivious to it. Or, it can be separated out by site or cell, similar to what it is now, where a user would have to manually select, say, the mountain system, when he or she drives out of the valley into the mountains.
It's very versatile. It can be controlled by individual radio, and/or by talk group. A talk group must be allowed in a specific cell, and a radio must be allowed in that specific cell, and on that specific talk group. And that level of control IS used in these types of systems. Its' the only way to manage channel resources.
There is a common problem that can crop up. If a unit radio was not completely programmed, it becomes possible for several units to go to some specific location, and one of them can't talk. It's like he's in a dead spot, and everyone else works fine. The system and unit programming is EXTREMELY complicated on these systems. I suspect that issues such as that were one of the things that held back the PSEC system from cutover for so long.
Jlanfn wrote:There are probably other reasons that zz can provide. He has much more experience and history with the county's radio technology.
Good grief... I could go on for days.
One thing cvrules90 can count on is, it won't be any easier for him to program his scanner than it is now. And we haven't even talked about encryption.