Non-comprehensive parts list:

  • baofeng uv-5r
  • Audio Transformers to remove AC Hum and ground loops
  • 15CM SMA Male to SMA Female Coax Cable Jumper Pigtail
  • SMA Female Jack to SMA Female Bulkhead Straight RF Coaxial Adapter Connector B1
  • CR1220 for GPS
  • 12V Car Charger Power Battery Eliminator For Baofeng UV5R Seiries Black New
  • Adafruit Ultimate GPS Breakout – 66 channel w/10 Hz updates – Version 3
  • DC 7V-24V to 5V 3A Step Down Buck LM2596 Arduino Module KIS3R33S than 5V USB
  • rapsberry pi 3
  • Roof top antenna
  • USB Soundcard
  • Still a work in progress.

    The hardest part about this project was selecting a USB soundcard that worked. Ultimately I found one I got on ebay for $1 10 years ago and it worked better than the 3 others I tried.

    I’ve included some config options for PPS, even though I am not using PPS at this time.

    Disable serial console
    In /boot/cmdline.txt remove console=ttyAMA0,115200 or console=ttyS0,115200 depending on Pi 2 or 3

    Enable UART and map PPS


    # needed for hardware uart

    Install needed packages

    apt install libgps-dev gpsd git libasound2-dev gpsd-clients pps-tools 

    Disable systemd gpsd

    systemctl stop gpsd.socket
    systemctl disable gpsd.socket

    Install direwolf

    git clone https://github.com/wb2osz/direwolf.git
    cd direwolf
    make install
    mkdir /etc/direwolf
    mv ~/direwolfconfigs /etc/direwolf 

    Set services to start on boot

    update-rc.d gpsd enable
    wget -o /etc/init.d/direwolf https://raw.githubusercontent.com/elafargue/aprs-box/master/config/etc/init.d/direwolf
    chmod +x /etc/init.d/direwolf
    ln -s /etc/init.d/direwolf /etc/rc2.d/S06direwolf
    chmod +x /etc/rc2.d/S06direwolf 

    Modify /etc/ntp.conf to use GPS by adding these lines

    server minpoll 4 maxpoll 4 iburst
    fudge time1 +0.130 refid GPS


    Design Box:

    I picked up a el-cheapo clear plastic enclosure for $1 to mount all the cables and boards in and keep things from shifting around. My plan is to eventually 3D print an enclosure once I have everything finalized.

    Works well for around town, but not enough power to hit distant repeaters except intermittently.

    I took it showshoeing up by bumping lake, didn’t hit BETHAL once. I was able to hit SHRINR from bumping. I believe the major issue to be lack of power from the 5W baofeng.

    I took it up showshoeing again this time at Hell’s crossing/Pleasant Valley and didn’t get a single ping up the pass. I did get a few pings on BETHAL on the way up, which I am happy about since I should have before.

    Since I am seeing long haul truckers with 25-50W APRS transmitters hitting repeaters hundreds of miles away with consistency, I can only surmise my little 5W chinese HT just isn’t getting out. What I really wanted to find was a dual band (2m/70cm) dual VFO radio to dash mount and dedicate the second VFO to APRS. However, I wasn’t able to find a good radio that fit the bill. Backup plan is to get a cheap dedicated radio for APRS.

    Thus enter the Mark II…