Simulcast or not?

[dgruver911]

If there is a better forum for this I apologize, just looking for some feedback...

We are in the planning phase of a P25 800 system for our county. Looking at 3-4 sites, around 600 radios, around 40 talkgroups. Remains to be seen whether we attach our system to the statewide P25 system or have our own with a possible future ISSI to the state system. If we join the state system, we are bordered on 2 sides by large metropolitan counties already on the state system; one is simulcast the other isn't. We have no state towers in our county, but every county around us has at least 1.

My question: We are working with 2 vendors right now for information and trying to figure out which direction we are ultimately going. One is suggesting simulcast, the other is not. The primary reason they give for sumulcast is a lack of available frequencies, which by my reseacrh is not accurate. Are there other compelling reasons to simulcast a system as small as ours? I don't see any need to have systemwide coverage by more than a small handfull of talkgroups, and what will happen with cross-over from surrounding counties? Looking to the experts who have been there for some guidance and suggestions. Thanks.

 

[hitechRadio]

Not sure where you are located but 700mhz would be a viable option and there should be avaliable frequecies. You would be using TDMA Phase2 at 700mhz.

Multicast is nice because you can have mixed number of channels at each site. Example, the most populated area have 5 channels and other sites you can reduce to 3 or 4 channels. Depending on expected loading at those sites. One down side to Multicast is scanning, Example if and user is affiliated at that site on talkgroup1 but he is prority scanning talkgroup2. If no one at the site he is on is affiliated on Talkgroup2 he will not hear that transmission. But there is an exception to this if, A system administrator can force talkgroup2 to always come out that site though, even when no one is affiliated with Talkgroup2.

Simulcast has advantages, uses less spectrum. Scanning is not an issue. But You will have to have the same number of channels at each subsite obviously. There is much more equipment associated with simulcast.

My opinion would be to join with the state system since the bordering large counties already are. Put in 700mhz Phase2 TDMA sites (if frequencies are an issue) otherwise 800mhz, and multicast. Just my opinion though. As i don't know your exact situation.