help with monitoring (via sdr) NXDN voice freqs

Are you a beginner or an expert? Have a question about monitoring? Or a seasoned pro who has some tips and advice? This is the forum for you. Class is in session at Scanning 101, no extra credit needed.
Post Reply
User avatar
Posts: 81
Joined: 09 Mar 2020 17:13

help with monitoring (via sdr) NXDN voice freqs

Post by riskan20 »

I recently set up a new "dongle (rtl-sdr v3) and using SDR# and DSD Plus. All new to me. I was able to get it all mostly working. So far I have been just searching the 450mhz band and found a few strong NXDN Data channels. It just endlessly streams "SYNC+ NXDN48 TB CCDATA". So control channels dont offer much. I did briefly stumble upon a voice freq and did hear a short transmission but I lost the freq and cant find it. I also found some DMR but couldnt get anything useful. Is there a list of some NXDN voice freqs I can try to monitor? Not sure who uses this mode. Apparently DSD plus decodes many of these modes. I also stumbled upon a federal safety service freq P25 on 408.200 encrypted though. But most of what I see are control channels. Not sure how to go about this.

SNE and Wiki Moderator
Posts: 1228
Joined: 29 Aug 2005 15:46
Location: Granby, CT

Re: help with monitoring (via sdr) NXDN voice freqs

Post by cdgordon »

There is an option to put the frequency into the Event log but I believe you need to be using FMPx so the programs can talk back and forth.
You don't say how long you are sitting on one of the Control Channels but I usually watch for a minimum of 24 hours on a weekday or a full week if I think it is something I am interested in (not oil companies, buses, garbage trucks, etc)
There is not a list that separates voice channels from control channels. You should be making your own notes so that you can try to figure out systems and how they work. You can use the Digital Freq search page but it is only license emissions and not what is actually used.


Post Reply