Decoding Mototrbo/DMR Signals during the Australian Formula 1 Grand Prix

1. MOTO-T-BRO
mototrbo/DMR
decodingONLINUX
Decoding DMR trunks on linux
Where What Who
Cyberspectrum
DMR Trunk Decoding
Tim Noise

2. tIMNOISE
• twitter/dnoiz1
• github/dnoiz1
• mIRC/dnz
• streetz/notorious D N Z
• tim@drkns.net
Aspiring Ham Radio Operator Lookalike

3. DIGITALMobileRADIOthe key word is digital. also mobile and radio
• open digital mobile radio standard
• P25 phase II and NXDN are the main competitor
• 6.25 kHz equivalent bandwidth
• proprietary AMBE+2 vocoder
• DMR + P25 II in a 12.5 kHz channel
• RF range 30 MHz to 1 GHz.

4. HARDWAREImplementsRadios are not all software

5. DuringTheGPWhy even look for this?

6. ScanningForStuffWhat was around
• FM stuff on 443.1mhz -> *
• Camera people
• TV / production people
• Italians
• Stuff what I don’t know what it is
• Normal RF traffic (neckbeards and couriers)

7. ScanningForStuffWhat was around
• SOMETHING ELSE AROUND 462.125mhz

8. DMRSAMPLEDECODEDspoiler, probably sounds better if you are good at air

9. SOFTWAREOnLinuxcheck your version dependencies
• GQRX
• Netcat
• mkfifo
• padsp (because /dev/dsp isn’t a thing anymore)
• dsd (and its depends)

10. SOFTWAREOnLinuxA Diagram

11. SOFTWAREOnLinuxcheck your version dependencies
• Install GQRX as normal, anything you’d normally
need for your SDR
• install dev dependencies for DSD (check the
GitHub wiki for downloads and links)
• https://github.com/szechyjs/dsd
• mkdir build && cd build && cmake .. && make &&
make install

12. cONFIGYourAudioSolutionSetting up a FIFO buffer and piping your raw audio
• MKFIFO!
• Netcat!

13. cONFIGYourAudioSolutionSetting up a FIFO buffer and piping your raw audio
• padsp wrapping dsd

14. cONFIGYourAudioSolutionSetting up a FIFO buffer and piping your raw audio
• Sending the audio to netcat over UDP from GQRX

15. cONFIGYourAudioSolutionSetting up a FIFO buffer and piping your raw audio
• (Un)Muting GQRX to swap between scanning and listening

16. OtherSystemsTOLISTENThis was pretty basic
• Actual radios
• SDR#/DSD+ on windows
• kinda similar on mac (see @zenmountainman)
• Other DSD implementations
• NOT in gnu radio live distro
• HackRF Portapack HAVOC firmware (?)

17. QUESTIONS?

18. tIMNOISE
• twitter/dnoiz1
• github/dnoiz1
• mIRC/dnz
• streetz/notorious D N Z
• tim@drkns.net
Aspiring Ham Radio Operator Lookalike