NAC code/number question

crippledchicken

Member
Premium Subscriber
Joined
Dec 28, 2004
Messages
438
Location
Butler County MO
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?
 

wbloss

Member
Premium Subscriber
Joined
Dec 19, 2002
Messages
611
Location
Joplin Mo
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?
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!
 

GTR8000

NYS Database Guy
Database Admin
Joined
Oct 4, 2007
Messages
8,132
Location
BEE00
The NAC allows similar radios to hear each other.
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
Premium Subscriber
Joined
Dec 28, 2004
Messages
438
Location
Butler County MO
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! (y)
 

GTR8000

NYS Database Guy
Database Admin
Joined
Oct 4, 2007
Messages
8,132
Location
BEE00
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! (y)
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.
 

scannerowner

Member
Joined
Aug 4, 2008
Messages
919
Location
NW Missouri
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.
 

wbloss

Member
Premium Subscriber
Joined
Dec 19, 2002
Messages
611
Location
Joplin Mo
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.
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
Premium Subscriber
Joined
Dec 28, 2004
Messages
438
Location
Butler County MO
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! :)
 

wbloss

Member
Premium Subscriber
Joined
Dec 19, 2002
Messages
611
Location
Joplin Mo
It may well be that the NAC has changed - several sites changed NAC a while back.
Unless you have an unusual feature turned on in the Uniden SDS series, there is no need to change site NAC.
 

crippledchicken

Member
Premium Subscriber
Joined
Dec 28, 2004
Messages
438
Location
Butler County MO
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 checking the database and, if I've interpreted things correctly I'm scanning 4 different sites
 

kc4jgc

Member
Joined
Mar 7, 2004
Messages
1,456
Location
Virginia Beach, VA
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.
 
Top