NC NAC list

[BCasto]

Is there a list of NAC codes for NC or at least for the area around Wake County?

I suppose 383 is Wake Co Simulcast but I am guessing.
I have been finding:
1F2
1F3
1F4
5C2
591

Thank you.

 

[drayd48]

Is there a list of NAC codes for NC or at least for the area around Wake County?

I suppose 383 is Wake Co Simulcast but I am guessing.
I have been finding:
1F2
1F3
1F4
5C2
591

Thank you.

I believe the 1F? are VIPER.
I would assume 591 would be carry city services.
I world assume the 5C2 would be the Durham and Fayetteville System.

 

[KE4ZNR]

Is there a list of NAC codes for NC or at least for the area around Wake County?

I suppose 383 is Wake Co Simulcast but I am guessing.
I have been finding:
1F2= VIPER
1F3= VIPER
1F4= VIPER
5C2=Durham
591=Cary

Thank you.

Remember that P25 trunked systems have NAC tones for system access and for use during failsoft.

Marshall KE4ZNR

 

[BCasto]

Thanks a bunch. Is there a way to derive the NAC from the system ID or some other info we have?

Marshall so NACs are used for system access. Does that mean if 2 nearby systems are using the same frequency that each will only "pay attention" to transmissions with the correct NAC?

My BDC996P2 will tell me the system ID if I hold on a control channel. It will tell me the NAC if I am in search mode held on a voice channel. Is there a way to tie a voice channel (frequency) to a specific control channel and therefore a specific System ID and antenna site?

Let's say I am searching for activity between 850Mhz and 855Mhz and stop on what looks like a P25 voice channel with a NAC of 1F2. Let's also say several Viper sites in range share this voice channel frequency. Which Viper site am I actually listening to? Would all affiliated or local sites use the same NAC? How are NACs assigned? - by antenna, by county, or how? Viper has a single system ID but seems to have multiple NACs. How are they mapped, determined, etc.?

Thank you for tolerating more questions... I just enjoy the heck out of learning this stuff.

 

[KE4ZNR]

Thanks a bunch. Is there a way to derive the NAC from the system ID or some other info we have?

Marshall so NACs are used for system access. Does that mean if 2 nearby systems are using the same frequency that each will only "pay attention" to transmissions with the correct NAC?

That is one of the ideas. Another way to help filter out other system's radio traffic (though 2 systems should hopefully not have the same freqs that close together).

My BDC996P2 will tell me the system ID if I hold on a control channel. It will tell me the NAC if I am in search mode held on a voice channel. Is there a way to tie a voice channel (frequency) to a specific control channel and therefore a specific System ID and antenna site?

More or less it is just another way to ID what system you are hearing. If you see a 1Fx NAC you can pretty much guarantee that freq is part of a VIPER site.

Let's say I am searching for activity between 850Mhz and 855Mhz and stop on what looks like a P25 voice channel with a NAC of 1F2. Let's also say several Viper sites in range share this voice channel frequency. Which Viper site am I actually listening to?

That is where programs like Pro96Com and Unitrunker come in handy. They can help you figure out what sites use which frequencies.

Would all affiliated or local sites use the same NAC? How are NACs assigned? - by antenna, by county, or how?

On a Wide Area Trunked system like VIPER NACs are assigned at the Site Level.

There is actually a setting within Motorola CPS that validates the NAC to the System ID:

Causes the radio to validate the upper 8 bits of the 16-bit System ID against the upper 8 bits of the 12-bit NAC (Network Access Code) received on the Trunking - control channel. If a match is not found, the radio does not attempt to register / affiliate to the Trunking site. Therefore enabling this field allows the radio to quickly match a site's NAC code with its System ID and quickly reject interfering Trunking System control channels. This selection applies for the current Trunking System.

Viper has a single system ID but seems to have multiple NACs. How are they mapped, determined, etc.?

It is purely up to the System Techs & System Admins which NACs are used at which sites though the first 2 numbers match up to the System ID. We have only 1 NAC for our 4 site system. VIPER with 200+ sites needs to use different NACs to help reduce the possibility of interference. BTW: Each site listing in the RR database has a section for site NAC code listing so feel free to submit any verified accurate NACs for sites that don't yet have them!

Marshall KE4ZNR

 

[BCasto]

RDU Airport NAC 5F1

 

[radioman2001]

This is all very interesting, maybe why I never seem to get reception on Viper when I travel through there. Yes I do get Brunswich Co OK when I am there, but I have never heard a peep out of NCHP while going to and from there. I usually resort to monitoring the channels conventionally. I have 20 to 30 mile zones setup with all the channel of a site for that area.
We don't have any large systems up her (NY State) so still in the learning phase on how to program my XTS and XTL (non-affiliate scan method).
So is there a method to this madness when programming, I do have every control channel loaded, but still no reception while in trunking mode.

 

[BCasto]

NAC 1F2 - Viper Durham Camden Avenue site 009
NAC 1F4 - Viper Durham Cole Mill Road site 015
NAC 1F0 - Viper Durham Brian Center site 147

 

[KE4ZNR]

Hey Brian, Make sure you check the VIPER database listing as a good number of the Central NC VIPER site NACs are already listed.
Thanks!


Marshall KE4ZNR

 

[PiccoIntegra]

Zone 1: 70 Sites, 9 NAC entries
Zone 2: 84 Sites, 0 NAC entries
Zone 3: 73 Sites, 0 NAC entries

It's a pretty common theme...

 

[BCasto]

Marshall, I have found some of the NACs are included. I have found one error and have added one along with some new frequencies on some of the sites so far. Unitrunker is pretty cool. When I do a "submit" I am also including peer/affiliate sites, LCNs, and in some cases a band plan. I understand the radio site admins make changes every once in a while and I hope I can provide updates when I find them. It is fun.

I hope I am using Unitrunker properly. I can't seem to find a way to produce the NAC when using it. So, I just use a second scanner in search mode (996P2) and it will show the NAC. I do have a question about Unitrunker. With some sites, the peer/affiliate list and frequencies lists are produced right away. On a couple sites, after running Unitrunker for several hours, new frequencies were added. Is that normal?

 

[BCasto]

Unique NACs

Having now looked at the NACs for many of the local Raleigh / Durham area VIPER system sites I have another question.

It seems NACs are not unique. Two of the systems I can receive at home have the same NAC. Am I crazy or overlooking something? Do the need to be unique?

 

[BCasto]

More NAC updates have been submitted..