Trunk Recorder, Airspy, and ConventionalP25

[blantonl]

Has anyone successfully gotten Trunk Recorder to work recording Conventional Project 25 frequencies using an Airspy?

I'm able to decode a Trunked VHF and 800 MHz P25 systems just fine, however when attempting to just record a simple VHF P25 frequency, I get a P25 recorder that fires up immediately and then never stops, and it doesn't ever seem to record anything.

Here is my config.json file. (recording 156.000 MHz which is a conventional P25 channel)

{
"sources": [{
        "center": 155000000.0,
        "rate": 10000000,
        "error": 0,
        "squelch": -50,
    "mixGain": 10,
    "lnaGain": 15,
    "gain": 15,
        "digitalLevels": 3,
        "digitalRecorders": 4,
        "driver": "osmosdr",
    "device": "airspy",
        "modulation": "fsk4"
    }],
    "systems": [
    {
    "type": "conventionalP25",
        "channels": [156000000],
    "talkgroupsFile": "convP25.csv",
        "shortName": "convP25"
    }]
}

This is what I see when I run trunk recorder:

[2019-04-27 15:14:36.826980] (info)   Call Timeout (seconds): 3
[2019-04-27 15:14:36.826997] (info)   Log to File: false
[2019-04-27 15:14:36.827014] (info)   Control channel warning rate: 10
[2019-04-27 15:14:36.827032] (info)   Control channel retune limit: 0
[2019-04-27 15:14:36.827049] (info)   Frequency format: 0
[2019-04-27 15:14:36.827064] (info)   Status as String: false
[2019-04-27 15:14:36.827086] (info)   [convP25]    Monitoring Conventional Channel: 1.560000e+08 Talkgroup: 1
[2019-04-27 15:14:36.834265] (info)        P25 Recorder Initial Rate: 500000 Resampled Rate: 31250 Initial Decimation: 20 Decimation: 16 System Rate: 30000 ARB Rate: 0.96
[2019-04-27 15:14:36.834333] (info)   P25 Recorder Taps - initial: 1515 channel: 1515 ARB: 757 Total: 3787
[2019-04-27 15:14:36.838221] (info)        P25 Recorder - Adjust Channel Resampled Rate: 31250 System Rate: 24000 ARB Rate: 0.768
[2019-04-27 15:14:36.838517] (info)       - Started P25 Recorder Num [4]    TG: 1    Freq: 1.560000e+08     TDMA: false    Slot: 0
[2019-04-27 15:14:36.838817] (info)   [convP25]    TG: 1    Freq: 1.560000e+08    Listening on Src: airspy

As you can see a P25 recorder starts up and it never stops until I quit the app, meanwhile nothing was ever recorded in that file. It doesn't seem to record any calls and instead starts up immediately infinitely recording nothing, Any ideas?

 

[blantonl]

I think I've gotten this figured out. It turns out that Trunk Recorder starts recording immediately and regardless of whether or not a call is active and then writes the files when the call terminates and then starts recording again.

So this means the audio files are created immediately after the last call ends, not when a new call begins. A kind of strange setup for Conventional Call processing. The json metadata files also reflect this timing... so some trickery is going to be needed to determine the proper call start times (maybe calculating and subtracting the call duration from the last updated timestamp on the file)

 

[NebraskaCoder]

Good to know and hear that you figured it out!

Sent from my SM-G975U using Tapatalk

 

[10-75]

Lindsay, I think this setting in the config file under "system" may help you...

• delayCreateOutput - [conventionalP25 only] this will delay the creation of the output file until there is activity, The options are true or false, without quotes. The default is false.

robotastic/trunk-recorder

 

[blantonl]

Excellent, thank you!