Type II Smartnet Simulcast

[jlanfn]

In a Motorola Type II Smartnet Simulcast system, can the system track which site a particular radio is getting the control channel from? Would that eliminate the need for voting equipment, as the system would assume the best audio will be from the site that the radio is "on"?

I'm trying to understand how it is possible for system users to add "filler" sites to a simulcast system that do not have all the frequencies of regular sites. How does the system know that radio "1234" is out of range of all the regular simulcast sites, so the talkgroup he is on needs to be limited to the frequencies available at the "filler" site?

 

[N4DES]

No the system cannot tell as the radio has no idea when it is in the simulcast zone because all of the sites are transmitting the same information at exactly the same time in pahse with each other. The voter is used for talk-back only and is a comparator that selects the best audio from only the sites that unsquelch. They are exclusive of each other and do not utilize each others information.

Now if your talking about a unit roaming from one site to an IR site that is being utilized as a filler, the subscriber makes that decision based on received signal strength, or RSSI, and only handshakes with the system when it makes the switch. When it handshakes it tells the controller the RID, talk-group that it's currently on, and which site it wants to affilaite with. The controller will look up all this information and either grant it or deny it based on the permissions programmed for the user and talk-group. If it denys it the radio goes back to the original control channel/site.

Hope that helps.
Mark

 

[guitarbrian30]

way cool

that makes some sense. thanks for talking normal. I understood what you were talking about!

 

[jlanfn]

Okay. Pardon my asking a few more questions. I still do not completely understand it.

Say someone wanted to add a filler site to a Smartnet system. The system has 15 voice-only frequencies and four rotating control channel frequencies. For whatever reason, the filler site would only have 7 total frequencies. What would the activity on the filler site look like? Would the filler site have to have the same four rotating control channels, or could it have it's own rotating or non-rotating control channel(s)? Would the information transmitted over the filler site's control channel be exactly the same content as a regular site's control channel, and would the filler site control channel always be active regardless of whether the system knew a subscriber unit was using the filler site? Given the potential for there to be, say, 10 voice frequencies active at once on the normal sites, how would the filler site handle that, since it only has 7 frequencies total?

It seems to me the more independent the filler site's operation is from the rest of the system, the more it acts like a separate cell in a Smartzone system.

 

[N_Jay]

Exactly right, the filler site is simply an additional cell.
Filler sites are independent, have their own control channel (or channels) and have the number of channels required to carry the amount of traffic expected in the filler area.

 

[jlanfn]

Okay, now I understand. Thanks.