Monday, April 27, 2020

Setting up TNC-Pi9k6 - Raspberry Pi Hat with Pi 4

Notes from my setup that others might find helpful:

Using latest build of raspbian

Ran os updates:
sudo apt update; sudo apt upgrade

Ran firmware update:
sudo rpi-update

Detecting the TNC and running getparams first time:

Following the manual here as it's for this particular hardware:
And additional help from this manual since it has much more information:

Serial Port - it should be on /dev/serial0. To enable it, do:
sudo raspi-config
Select option 5 for Interfacing options
Select option 6 for Serial
Say "no" to the login shell question.
Say "yes" to serialport hardware question.
Now you should see output when you do "pitnc_getparams /dev/serial0 0"

Software Setup

Following this guide for software setup:
Skipped the direwolf stuff for now since I'm using the TNC

Tuesday, April 21, 2020

APRSdroid, Mobilinkd TNC2, and Baofeng UV-5R Setup

I couldn't find concise settings for this pairing of components online, so this documents the setup that is working for me.  I'm able to send and receive APRS packets using APRSdroid on my android phone.

Phone Setup

  • Pair your phone with the Mobilinkd TNC2, password is 1234
  • Install the "Mobilinkd TNC" app
  • Install APRSdroid app.  If you're on android 10 or later, you'll need to sideload their offline map of the program as the regular version crashes.  If you want maps functionality in Android 10, you can install the "Backcountry Navigator XE" app and enable APRSdroid integration in it's setting menu. 

UV-5R Setup

I did this all in VFO mode rather than programming the station in.  You can probably program it from chirp as a simplex station and several of these settings will be made automatically for you.  Just make sure you have the rest of the settings correct in the radio.

  • Tune to 144.390
  • 0 - SQL: 1
  • 2 - TXP: HIGH
  • 3 - Save: OFF
  • 4 - VOX: 10
  • 5 - WN: WIDE
  • 6 - ABR: 5
  • 7 - TDR: OFF
  • 9 - TOT: 60
  • 10 - R-DCS: OFF
  • 11 - R-CTCS: OFF
  • 12 - T-DCS: OFF
  • 13 - T-CTCS: OFF
  • 14 - VOICE: OFF
  • 16 - DTMFST: OFF
  • 17 - S-CODE: 1
  • 18 - SC_REV: TO
  • 19 - PTT_ID: OFF
  • 20 - PTT-LT: 5
  • 21 - MDF-A: NAME
  • 23 - BCL: OFF
  • 24 - AUTOLK: OFF
  • 25 - SFT-D: OFF
  • 26 - OFFSET: 00.000
  • 32 - AL-MOD: TONE
  • 33 - BAND: UHF
  • 34 - TDR-AB: OFF
  • 35 - STE: OFF
  • 36 - RP-STE: OFF
  • 37 - RPT-RL: OFF
  • 38 - PONMSG: FULL
  • 39 - ROGER: OFF

"Mobilinkd TNC" App Setup -

  • Connect the TNC2 to the Radio if you haven't already. 
  • Pair the TNC2 with your phone if you haven't already
  • Open the Mobilinkd app and "Connect" to the TNC.  Make sure it has the blue light blinking and press the button on it if not. 
  • In Audio Output Settings:
    • PTT Style: Simplex
    • Output Volume: 100 - I had to find this by trial and error.  I'd suggest starting here and adjusting until you see your station register on  You'll have to alternate between connecting to the TNC with the Mobilinkd app and APRSdroid to adjust this setting and test a few times.  
  • In Audio Input Settings - follow the process in the TNC2 documentation. 
    • Shift the radio off of the aprs frequency temporarily
    • Hold the call button on the side of the radio and adjust teh radio volume  until the display on the phone shows the yellow bars light constantly and occasionally one of the red bars lights up. Don't un-check Attenuate input unless you find that you've turned the volume all the way up on the radio and still can't get the volume level high enough on the phone. 
  • Modem Settings:
    • Check the DCD option.
  • That's it!  

APRSdroid Setup

  • In the Settings menu:
    • Set your call sign
    • Set "APRS digi path" to: WIDE1-1,WIDE2-1
    • In APRS Connection Preferences:
      • Set "Connection Protocol" to: TNC (KISS)
        • Yes, do this even though there's a separate TNC2 optoin listed. 
      • Set "Connection Type" to "Bluetooth SPP"
      • Select the TNC2 in the TNC Bluetooth Device menu
    • In Location Settings:
      • Set "Location Source" to: Periodic GPC/Network Position
      • Set "GPS Precision" to: Low
  • Now start tracking and you'll see it broadcast your call and location in green.  
    • If everything's working, someone's system will see this and report it to, etc. 


  • I had limited success with the stubby antenna.  If you go outside and hold up the radio, it might help!  Best thing I did was plug into my DBJ-1 antenna above the house.  If you're backpacking, you might want to invest in a DBJ-2 or similar for good reception. 
  • If you want to know that your messages are getting out, even if you can't receive, try using the SMS gateway to relay texts to your phone.  Link Below. 
  • The audio level settings in the mobilinkd app are important. 

Reference Links:

APRSdriod Offline maps version:
Mobilinkd TNC2 User Guide:
UV-5R Menu guide:
SMS Gateway:
DBJ-1, DBJ-2 antennas:  They're sold for $40 on ebay and made by Ed's students to raise money for their program at UC Santa Cruz.  Good money spent for a quality antenna.