DSDPlus NXDN Conventional Private Calls

[THR1972]

Hello! I've spent probably far too long searching the forum for this and not finding it. I'm currently using DSD+ FL and FMP24 on a Windows 10 machine to monitor a NXDN48 conventional frequency. It works really well considering my antenna is the one that was included with the RTL-SDR blog v3 I ordered from Amazon. I'd say it's doing 99% of what I want it to, but I cannot figure out private calls. I know they're happening because occasionally I will hear on the frequency say "can you switch to private" but I don't pick anything up and the event log does not catch any private or encrypted traffic. (I have follow encrypted voice calls enabled and have private calls on high priority in the menus.)

There are no other frequencies listed for this entity. The "Tone" box on RRDB for my frequency says "10 RAN" but I have no idea what to do with that information. How are private calls handled on NXDN conventional systems? Are these people just using a different frequency not registered to them? How can I monitor private calls? TIA!

***ETA*** I just re-read the warning notice about posts on encryption. To be clear, I'm not asking how to break into encrypted traffic. I don't believe these calls are encrypted based on the information I've read elsewhere on the forum. I just clearly do not understand how CTCSS/DCS/unit-to-unit calls work and what, if anything, I can do to monitor that.

 

[dave3825]

***ETA*** I just re-read the warning notice about posts on encryption. To be clear, I'm not asking how to break into encrypted traffic.

No worries about that. Your question is far from what that's meant for.

When they say switch to private, it could very well be another freq that might not be listed on this site. If you look at the agency listed, if there is an FCC license listed, you can search that and see if there are any other freqs that might be active. Many agencies have more than one license so when your viewing it, look for the FRN (FCC Registration Number) and run a search by FRN on the FCC site and it will display everything associated with that agency.

FCC FRN Search Go here and search by call sign, frn or name.



What does your DSDPLus.radio file say? Do you see any -1 entries as mentioned in the file?

DSDPlus.radios

; DSD+ 2.465; radio records
;
; this file is populated automatically by DSD+
;
; you can edit this file while DSD+ is running
;
; line format: protocol, networkID, group, radio, priority, override, hits, timestamp, "radio alias"
;
;
; protocols:
;
; ProVoice
; D-Star
; Fusion
; dPMR
; IDAS
; NEXEDGE48
; NEXEDGE96
; DMR
; TIIIStd
; TIIInonStd
; DCDM
; Cap+
; Con+
; XPT
; P25
; X2-TDMA
;
;
; special group values:
;
; -1: only private calls seen
; -2: group unknown

here are no other frequencies listed for this entity. The "Tone" box on RRDB for my frequency says "10 RAN" but I have no idea what to do with that information.

Ran is like a pl tone. It allows different agencies to speak on the same freq without hearing each other. Police could use Ran 10 and Fire could use Ran 5 and police won't hear fire and visa versa.

 

[THR1972]

No worries about that. Your question is far from what that's meant for.

When they say switch to private, it could very well be another freq that might not be listed on this site. If you look at the agency listed, if there is an FCC license listed, you can search that and see if there are any other freqs that might be active. Many agencies have more than one license so when your viewing it, look for the FRN (FCC Registration Number) and run a search by FRN on the FCC site and it will display everything associated with that agency.

FCC FRN Search Go here and search by call sign, frn or name.

View attachment 162213

What does your DSDPLus.radio file say? Do you see any -1 entries as mentioned in the file?





Ran is like a pl tone. It allows different agencies to speak on the same freq without hearing each other. Police could use Ran 10 and Fire could use Ran 5 and police won't hear fire and visa versa.

I don't have any -1s in my Radios file. I do note several other frequencies listed under that call sign on the FCC site. A few of the frequencies are listed on the RRDB as belonging to other agencies, but not all of them. I will add those to my scan list and see if anything pops up. It looks like a couple of them are just FM frequencies though.

**ETA** Some of these frequencies look like they're repeater inputs. The only non-accounted for frequencies that are not inputs are FM.

 

[dave3825]

When looking at the license, go with the FB (fixed base) ones. The MO are input freqs and usually lower powered.

 

[RaleighGuy]

but I cannot figure out private calls. I know they're happening because occasionally I will hear on the frequency say "can you switch to private" but I don't pick anything up and the event log does not catch any private or encrypted traffic. (I have follow encrypted voice calls enabled and have private calls on high priority in the menus.)

As you haven't said what agency or type of system you are talking about. One possibility, if this is a facility or building rather than wide area system, is that the private could be a simplex frequency that you can not pick up unless you are close. While often called private it can also be a talk-around channel. I've seen this used in some federal facilities.

 

[THR1972]

As you haven't said what agency or type of system you are talking about. One possibility, if this is a facility or building rather than wide area system, is that the private could be a simplex frequency that you can not pick up unless you are close. While often called private it can also be a talk-around channel. I've seen this used in some federal facilities.

It's law enforcement. Sorry, I probably should have specified. It's a rural county that shares one centralized dispatch between law enforcement and fire from the county and several cities.

 

[THR1972]

Is it possible that they’re calling car to car direct? If so, can you pick up those transmissions with an SDR?

 

[racingfan360]

Is it possible that they’re calling car to car direct? If so, can you pick up those transmissions with an SDR?

If those private calls were going over the conventional repeater system (encrypted or not) then you should either hear them or at least see the activity on DSD+. Clearly you're not seeing that, so I'd assume (1) they're using the same rados but talking on direct mode (2) they're on a different frequency or (3) they're using a completely different comms system. I assume you're monitoring the repeater output frequency atm. So to eliminate (1) try adding the input frequency for the repeater. Note you will have to be in range of the transmitting radio (as a rule of thumb, that means within line of sight), it will be relatively low power, and your standard antenna probably isn't going to be great unless you are very close to the transmitting radio.

 

[DaveNF2G]

Check the county's local government frequencies - highway, water, sewer, etc.

 

[Whiskey3JMC]

Is it possible that they’re calling car to car direct? If so, can you pick up those transmissions with an SDR?

Assuming encryption not a factor, use DSDPlus. SDRTrunk although it can monitor conventional traffic doesn't as of date of this posting support NXDN