Pat + Winlink with handheld radio and handheld Mobilinkd TNC

A previous posting showed how to set up Winlink through basic internet (Telnet). Internet/Wifi may or may not be available in any emergency, however, so it is important to be able to work Winlink over a VHF/UHF radio – which is the main benefit of WINLINK over e-mail, after all. To get this working you will need a radio, a TNC, and computer with the Pat or Winlink program. For my test I use a Yaesu FT-70 handheld, Mobilinkd TNC3, and Pat on a Linux computer.

This makes a much smaller Winlink setup than most, though a 5 watt radio will be needing a bigger antenna if the Winlink packet gateway repeater is miles away.

FT-70 handheld radio, Mobilink handheld TNC, and laptop.

The Mobilinkd device needed some setup through the mobile app, which is detailed in its documentation. I had to test getting it working a few times, I found it should always connect to Android’s bluetooth device immediately after turning it off and on. I had to hit the reset button when the green light stuck, once, and once again before I finally got it working.

Firstly, if you have a four-link Yaesu cable plugging in to the Mobilink, you will have to use the Android/ios configurator app to switch it from PTT Simplex (Kenwood and Chinese HTs) to PTT Multiplex (Yaesu, Icom, Alinco and others) as noted in the documentation.

You may get an error upon trying to connect even with it recognized by your computer. As with most usb devices you can use “lsusb” in terminal to list all usb-hub devices, to see that they are recognized. Remember to use a real data Micro-usb cable, not the charge only cables that come with many flashlights and gadgets these days 🙂

The instructions here may help. First install and set AX25Tools:

$ sudo apt-get install ax25-tools
$ sudo nano /etc/ax25/axports

Add your callsign in a line at the end of axports file like so:

wl2k  YOURCALLSIGN   9600 255 7 Winlink

Now ax25 works, but if you try Pat you will have the wrong default path. If you try it you would get:

 Unable to establish connection to remote: no such file or directory

In this case, the device isn’t /dev/ttyUSB0. On Ubuntu, list serial devices with:

$ ls -lah /dev/serial/by-id
total 0
drwxr-xr-x 2 root root 60 Jan 10 19:47 .
drwxr-xr-x 4 root root 80 Jan 10 19:47 ..
lrwxrwxrwx 1 root root 13 Jan 10 19:47 usb-Mobilinkd_LLC_Mobilinkd_TNC3_v2.1.1_208F33A4464B-if00 -> ../../ttyACM1

Unfortunately this /dev/serial/… path is a link that doesn’t work with “kissattach” command for kiss protocol, use the “ttyACMX” for the assigned path on your system, like so:

$ sudo kissattach /dev/ttyACM1 wl2k
AX.25 port wl2k bound to device ax0

At the terminal enter:

 pat configure

and change the quoted path here to the appropriate full path:

 "serial-tnc": {
    "path": "/dev/ttyACM0",

Running Pat in the browser

To start up Pat locally with the new values, at the teminal, next run:

pat http

and open http://localhost:8080/

Connect, receive, or send in the same way you would with internet and “telnet”, but use “ax.25” option like so:

Connect to remote node screen on Pat for Winlink

Note that you have to set the frequency manually, which is listed under the list button if you forget what your nearest Winlink packet radio station is. The “freq” setting in this case with this device, does nothing. Click connect to send and receive inbox and outbox.

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