NXDN - How To Find Network ID(s) - Control Channel Monitoring Didn't Work

[AB9NN]

I tried following these instructions:

I have a correct control channel per RadioReference.com
I have SDR# tuned and using NFM and 4,000 bandwidth
I see the strong RF transmissions on the control channel
I have DSD+ FastLane 2.155 started by itself with VB Cable as output from SDR# and defaults to input to DSD+
No wave form in Source. No presentation of network ID.

I went back to DSD+ and FMP24 in scan mode. I see frequencies changing. I see RF and waveforms in Source as scan hits transmissions
No network IDs shown anywhere.
Tried searching Google, FCC license listing and RadioReference.com listing pages and links. No joy!

 

[slicerwizard]

I have SDR# tuned and using NFM and 4,000 bandwidth
I see the strong RF transmissions on the control channel
I have DSD+ FastLane 2.155 started by itself with VB Cable as output from SDR# and defaults to input to DSD+
No wave form in Source.

Volume level turned down in SDR#?

Your problem has nothing to do with NXDN...

No presentation of network ID.

With no audio getting to DSD+, wouldn't any other result be rather odd?

I went back to DSD+ and FMP24 in scan mode. I see frequencies changing. I see RF and waveforms in Source as scan hits transmissions
No network IDs shown anywhere.
Tried searching Google, FCC license listing and RadioReference.com listing pages and links. No joy!

Why are you scanning? Just sit on the control channel. They're blindingly obvious in the spectrum display...

 

[AB9NN]

Volume level turned down in SDR#?
Your problem has nothing to do with NXDN...

With no audio getting to DSD+, wouldn't any other result be rather odd?

Why are you scanning? Just sit on the control channel. They're blindingly obvious in the spectrum display...

Multiple services running NXDN. Went back to 1 service, 1 Freq. In SDR# there are two ways to pipe to / from VB Cable. Selected the other method and got a nice wave form. Waited for transmission and no networks were documented. Made sure that the P25 network data was removed from the DSD+ Networks file and that the file was appropriately initialized. Dumb question alert! If this frequency is all encrypted, would I even see a network ID or would the network ID be in the clear and the data and voice be encrypted by themselves? Newbie. Curious newbie but a newbie. Scanned thinking if it was an encryption issue on one service maybe scan several and see if I could find a network ID from any of several. Understand slow scan may reduce chances of any hits, depending on how sporadic they are.

 

[slicerwizard]

Multiple services running NXDN. Went back to 1 service, 1 Freq. In SDR# there are two ways to pipe to / from VB Cable. Selected the other method and got a nice wave form. Waited for transmission and no networks were documented.

If you're waiting for transmissions, you're not monitoring control channels. No control channels means no networks and no network IDs.

Made sure that the P25 network data was removed from the DSD+ Networks file and that the file was appropriately initialized.

I don't understand the need for this.

Dumb question alert! If this frequency is all encrypted, would I even see a network ID or would the network ID be in the clear and the data and voice be encrypted by themselves? Newbie. Curious newbie but a newbie. Scanned thinking if it was an encryption issue on one service maybe scan several and see if I could find a network ID from any of several. Understand slow scan may reduce chances of any hits, depending on how sporadic they are.

Voice encryption has no impact on network data. But you're obviously monitoring conventional channels, not trunked/networked systems.

 

[AB9NN]

If you're waiting for transmissions, you're not monitoring control channels. No control channels means no networks and no network IDs.

I don't understand the need for this.

Voice encryption has no impact on network data. But you're obviously monitoring conventional channels, not trunked/networked systems.

Re: Control Channel or Not - Please review this page: https://www.radioreference.com/apps/db/?ctid=1236 and scroll down to the first Benzie County table and find the row that lists 156.240 Mhz and a NXDN listing for KQJ233 RMBenzie RoadsRoad Commission NXDN Public Works. Is the frequency listed - 156.240 supposed to be a control frequency? When I monitor that frequency visually via the waterfall I see noise floor and an occasional transmission which can be for an extended period. I hear the same thing through the speakers. When I monitor a P25 control channel I see a continual strong wave on the waterfall and see codes scrolling very quickly in the softwares. Trying to understand the listing and frequency actual behavior. Saw some YouTube video for a software called Go2Monitor that could figure this all out with a few clicks - but for Government sale only and export.

 

[cg]

Conventional (not trunked) NXDN. You are likely getting what you should. The database listings at the bottom of each county are the trunked systems, frequencies within each town are for the conventional.

chris

 

[dave3825]

156.240 supposed to be a control frequency?

156.240 is listed in the database as a conventional frequency. It's also listed with the fcc as Public Safety Pool, Conventional License - KQJ233 - BENZIE COUNTY ROAD When you click on either location, it only lists 1 freq 156.240.

Do conventional nxdn freqs display a network id? That should be the question.

I monitor a few conventional nxdn freqs and even tho they display talk groups, they do not display any network info. Just Nextedge48 TB (for what I monitor) .

As far as dsd networks file. Trunked systems display a network id. If your networks file has that id listed with a name, it will display that name in the event window. If you do not have a name associated with the id, or no entry at all, it will just display the id, and no name.

I went back to DSD+ and FMP24 in scan mode. I see frequencies changing.

What exactly is in your fmp24 scan list and what exactly are you scanning? You will see what ever freqs are in the scan list change based upon signal activity. When it finds something, it should stop on that. Then resume scanning.

If you only want to listen to a single conventional freq, ie:156.240, then there's no need to scan.

Made sure that the P25 network data was removed from the DSD+ Networks file and that the file was appropriately initialized.

Removing anything from the networks file will prevent the system name from being displayed when you are monitoring a system that's entry was removed from the file. So then you have to go to the database and look up the id to know who it is.

 

[AB9NN]

IT WORKS! The idea that a NXDN (out of newbie-ism-ness) frequency had no control channel was not on my radar. I made a few quick changes to two bat file and I am hearing voices - clearly decoded - and (bonus round) I launched LRRP.exe and everything works as expected there. LOTS of data. Here are my two bat files and thank you. I also had to create a FMP frequency list - plugged in two frequencies and everything worked.

FMP24 -i2 -o20003 -P0.0 -f156.240

DSDPlus -e -fa -i20003 -o1

In the FMP24 bat file - Note that I run three RTL-SDRs. #1 is for HF (works really well) and uses a SpyVerter to convert the low frequencies to a higher frequency that the RTL-SDR is capable of tuning. So the input is RTL-SDR #2. It just finds it on it's own. Per advice, no filters used and allow it to figure out on it's own what the mode is.

In the DSDPlus bat file - not that -o1 is to my Desk Speakers so that I can hear the audio as decoded.

I had, per advice, made a copy of my P25 folder and so for clarity I went through and cleaned-out some data in the various files that related only to the P25 system. I wasn't sure if the software would ignore that data or be confused by it - so I eliminated it to the extent practical and necessary. Seeing Group IDs, 246 radios saved, etc.. Looks to be functional! Never did document a Network ID for the system to work. Will do that if and when I see one. Thanks! Learning...

 

[DRL-XM43]

"In the DSDPlus bat file - not that -o1 is to my Desk Speakers so that I can hear the audio as decoded."

If you are set up correctly this should not be needed....? DSD+ should be decoding to your main speaker unless your audio defaults are incorrect.

 

[AB9NN]

I seem to have to change my Windows Sound settings for Default Audio from Desk Speakers to VB Cable and back when I listen to an FM Broadcast station in SDR# and then do NOAA Wx Satellite decoding and need to route the audio to WxToImg. Just seleting VB Cable in SDR# doesn't seem to cut it...

 

[DRL-XM43]

I seem to have to change my Windows Sound settings for Default Audio from Desk Speakers to VB Cable and back when I listen to an FM Broadcast station in SDR# and then do NOAA Wx Satellite decoding and need to route the audio to WxToImg. Just seleting VB Cable in SDR# doesn't seem to cut it...

When listening to FM in sdr# you would not change your windows default sound settings you would change the audio output in sdr# to your speakers from vbcable.

If you are feeding VBcable later you would reverse the selection in SDR#. There should be no need to change the windows default settings they should always remain as default output main speakers and default input VBcable.

If you left the windows defaults alone you would not have problems with DSD+, it would listen to the right input and output to the main speakers, regardless of using vbcable or using tcp connection to dsd+.

You could even leave SDR# audio as vbcable and run everything through DSDplus, if you use the -m1 switch it will happily pass your FM broadcast directly through to your main speakers thus having to avoid even changing sdr# audio output.

You would set WxToImg to listen to vbcable in the settings.

 

[AB9NN]

Wow! Thanks! That cleared-up a bunch of things. When I do that though, I have to mute my Windows Volume control so I don't hear the tones of the passing weather satellite. That's OK if everything else works. I had been going the other route so I could listen to HF at the same time on another dongle. This method gives best image so I will likely stay with that. I have already selected as input on WxToImg the VB Cable.

 

[DRL-XM43]

Wow! Thanks! That cleared-up a bunch of things. When I do that though, I have to mute my Windows Volume control so I don't hear the tones of the passing weather satellite. That's OK if everything else works. I had been going the other route so I could listen to HF at the same time on another dongle. This method gives best image so I will likely stay with that. I have already selected as input on WxToImg the VB Cable.View attachment 67867

Glad that helped, if you are having to mute windows audio there is still something not quite right, the only thing I can think of is you may have "listen to this device" checked in the windows vbcable settings. This should be unchecked.

Also in DSD+ batch files you should not have -o(X) as well as -o(tcp) that can cause distortion since you are sending processed audio twice.