crippledchicken
Member
Should all counties in mo be using the same nac code? All the counties come in showing 1NC8 is this normal for the missouri statewide wireless interoperable Network?
NAC code/number question
- Thread starter crippledchicken
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crippledchicken
Member
(Correction) should be 1C8
doctordialtone
Member
The NAC code is administered by the System Admin so it's up to them.
The NAC allows similar radios to hear each other.
The NAC is set for each tower. They are all similar: 1CB, 1C8, 1C2, 1CE. BUT Don't confuse with the sysid of 1CE also!
Generally the opposite is intended when it comes to trunked systems. The NAC prevents co-channel interference when frequencies are reused at multiple sites. Especially true for larger systems such as statewide, where there are a finite amount of frequencies that can be used.
crippledchicken
Member
I was just curious if all the p25 transmissions should all say p25 nac 1c8 at the bottom so I guess the other counties being on the same system is why the 1C8 never changes no matter which county is transmitting on p25. Thanks Folks! 
The NAC is assigned per-site in a P25 trunked system. How many sites are you scanning? If just one, then yes every transmission at that site, regardless of user or "county", would have the same NAC.I was just curious if all the p25 transmissions should all say p25 nac 1c8 at the bottom so I guess the other counties being on the same system is why the 1C8 never changes no matter which county is transmitting on p25. Thanks Folks!
scannerowner
Member
I'd be curious to research if each Region has it's own NAC?? That'd be interesting to see see. Some sites are border though.
doctordialtone
Member
scannerowner
Member
Ha, my bad! I'll do some research.
In MOSWIN you can see the site(tower) NAC IF it has been reported to the RR database. Click on a site/tower name - for example, site #1 Americus. A second detail screen will popup with more info including the site NAC (1C1 is Americus). Back at the main MOSWIN page note that Americus' site control channel in red is 170.3875. If you look further in the site list you will see this frequency is re-used in TEN other sites in Mo. The Site NAC of 1C1 is kind of like a PL or CTCSS that only unlocks the Americus site when used on 170.3875.
crippledchicken
Member
When I looked in the RR Database, I found that Doniphan mo. site NAC was listed as 1C6 but it always shows 1C8 at the bottom of the scanner. It says it was updated the 17 of this month. Last night I noticed the audio seemed like it wasn't decoded very well or something. Should I change the Site NAC to 1C6 or just set the scanner to ignore if there's no way to change the NAC code? Thanks!
scannerowner
Member
I bet my assumption is probably wrong then.
crippledchicken
Member
I was checking the database and, if I've interpreted things correctly I'm scanning 4 different sites
kc4jgc
Member
Do you need to program the NAC for a trunked system? I've only programmed those for conventional P25 repeaters. I don't believe there's a way to program trunked system NAC's in WIN500.
No, not necessary.
Only the Uniden SDS series scanners allow you to program a Site NAC for trunked systems, however it's not required or necessary to do so.
kc4jgc
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