Brian,

 

Phase-I FDMA LSM (Simulcast) and Phase-II TDMA systems require the CQPSK demodulator option.   Change your command line from (-D fsk4) to (-D cqpsk), then

add  (-V) to enable the vocoder that compliments  the (-2) Phase-II TDMA option.

 

Bill, WA8WG

 

 

From: op25-dev <op25-dev-bounces@lists.osmocom.org> On Behalf Of Brian Rak
Sent: Tuesday, April 14, 2020 8:24 AM
To: op25-dev@lists.osmocom.org
Subject: [op25-dev] P25 P2 corrupted audio?

 

I've been trying to use OP25 to listen to a Project 25 Phase 2 system, and so far all I've managed to get is weird corrupted audio out of it.  It almost sounds like the audio isn't being decoded at all, and it's just playing me the raw bit stream.

 

I'm using:

 

# ./rx.py --nocrypt -f 770081250 -N 'LNA:47' -2 -T trunk.tsv -l http:192.168.5.134:4445 -v 8 --args 'rtl' -S 274000  -w -W 192.168.5.224  -q 2 -D fsk4

 

(have tried with and without the fsk4).  

 

I do see debug output that seems to indicate it's following the channel properly: https://gist.githubusercontent.com/devicenull/1086fe103f751be9103a86496b46709a/raw/920fa584beab0ff3ae7f0735fe6a6750023440d3/gistfile1.txt

 

I'm listening in on a remote device with vlc: vlc.exe --clock-jitter=500 --network-caching=0 --demux=rawaud --rawaud-channels 1 --rawaud-samplerate 8000 udp://@:23456

 

The machine I'm running OP25 on doesn't really have a sound setup (it's a server, no GUI or speakers), so I can't really confirm if the issue is with the sound or VLC.

 

Any suggestions?