SDS200 NAC

TedTobias

Member
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Feb 28, 2004
Messages
156
Location
Bradenton Fl.
Hi,
What is NAC, I noticed it in my SDS 200 settings And what is it used for?

Thanks so much!
Theodore
 

sonm10

Central MN Monitor
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Nov 19, 2016
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142
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Sauk Centre, Minnesota
It is like ctcss or dcs tones on analog only for p25. Nxdn will have ran or area and dmr will have color codes

If unfamiliar with these codes, they allow multiple users access to the same frequency and mode of operation using different codes. There will still be interference, though.
 

bobruzzo

W1AV
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Joined
Nov 4, 2019
Messages
826
Location
Cranston, Rhode Island
Thank so much. where do you get the codes from?

Theodore
If you have an SDS200 (like me) it will automatically display NAC code when scanner stops on a P25 transmission. To make sure, go to SETTINGS>Site NAC Operation>Use site NAC
If you use Sentinel or whatever software to program scanner you can also set individual NAC's for stand alone (Not trunked) P25 freqs. For example my state (RI) is on a P25 simulcast system. But my hometown Police doesn't use it. They are on their own 482 Mhz P25 system. So the NAC on their frequencies is different from the state system.
 

n1chu

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Oct 18, 2002
Messages
845
Location
Farmington, Connecticut
Sonm10’s comment “There will still be interference, though.” relates to the use of the same frequency. Although differing NAC’s may be used, a signal can be present but ignored by your scanner because it’s not using the same NAC as your scanner. This signal, although intelligible with the proper NAC, will have the same effect as a high noise floor on the frequency. What this means to us is this... there may be times when we don’t receive a transmission as clearly as usual, and start thinking there is something wrong with either the transmission or our scanner, when all it amounts to are two signals using the same frequency at the same time.

Thanks to Somn10 for mentioning this. It’s another instance (there are a few) that can create confusion, especially with a newbie who just plunked down hundreds of dollars on a state-of-the-art scanning receiver only to find it’s not performing as advertised, at least in their minds... when all it was is just another instance of a lack of knowledge on how things work. There is nothing wrong with the scanner in situations such as this.
 

sonm10

Central MN Monitor
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Joined
Nov 19, 2016
Messages
142
Location
Sauk Centre, Minnesota
Thank so much. where do you get the codes from?

Theodore
Depends on type of system. For conventional frequencies it will be in the tone column. For trunk systems it is a little more hidden and in the site information. Click on the site name will reveal site information
 
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