@jasoyeom
Unfortunately, NXDN (and DMR for that matter) is a different system than P25. The good thing about P25 for us radio enthusiasts is that the information and frequency for the voice channels can be calculated from data sent out by the control channel. That is how both scanners and DSD+ can monitor a P25 system by only monitoring the control channel. The frequency for the voice channel will be calculated and the second instance of FMP24 will be tuned to monitor the conversation.
NXDN control channels do not provide this type of information so monitoring an NXDN trunking system is more complicated. Luckily, it looks like someone has already done the work of decoding this system and giving you the information that you need to plug in to DSD+.
If you go to the page for the system you are trying to monitor and pick out the specific site that you want to monitor (I am not aware of a way to monitor more than one site with DSD+ but if there is a way, I am sure someone will pop up with this information). Anyway, you need to click on the Name of the site that you wish to monitor. When you do, you will be able to find the Site Frequency Table toward the bottom. This will give you the control channel along with the other channels used by the site and pay close attention to that number in the CH ID column. Unlike P25, you have to manually tell DSD+ (scanners as well) what the channels are and the ID, also known as the LCN, so that DSD+ can properly tune to the voice channels.
I'm going to use the Fonthill site (
Fonthill Site Details (OnQ Network)) as an example but you can do the same with any site in the network. You will need to open the DSDPlus.frequencies file with a text editor such as notepad.exe and put the following information in it and save it (the information at the top should already be in the file but I am including it to explain the line format). A semicolon marks the line as a comment and DSD+ ignores it. Handy for commenting your entries.
; DSD+ frequency file
;
; line format:
;
; protocol, network ID, site number, OTA channel number, TX frequency, RX frequency, sort order
; Fonthill Site:
NEXEDGE48, 202, 5, 18, 420.54375, 0.0, 0
NEXEDGE48, 202, 5, 21, 420.64375, 0.0, 0
NEXEDGE48, 202, 5, 24, 420.74375, 0.0, 0
NEXEDGE48, 202, 5, 27, 420.84375 , 0.0, 0
NEXEDGE48, 202, 5, 30, 420.94375 , 0.0, 0
Entries explained:
- As per the information at Radio Reference already, the protocol is 4800 baud NextEdge so NEXEDGE48 is set as the protocol.
- The network ID for the system you linked to is 202.
- The site ID for the Fonthill site is 5.
- The OTA Channel Number coincides with the CH ID for that site. This number is
important as it tells DSD+ what frequency to tune to when the control channel sends out a channel number.
- Of course, the next column is the five frequencies for this site
- Leaving the remaining values as 0.0 and 0 have worked for me based on instructions found here on the Radio Reference forums.
Take the closest site that you want to monitor and get the information from that page by clicking on the name of the site on the main OnQ Network page and change the data above and enter it in your DSDPlus.frequencies page.
There are other entries that you can put in other text files to properly name the system but the above should at least get the site decoding data and audio! Good luck!
On a quick site note, I have noticed that, with the latest versions of DSD+ Fastlane, the blue audio dialog boxes do not show up any more. Not sure if this is something you can turn back on or not but I am not seeing them any longer.
