Winlink under Linux
Winlink is an email service that allows people to send and receive email from
        anywhere in the world using HF radio. I wanted to try it out but on Linux, and without using WINE.
        To do this, there are three components.
The Winlink client
Pat is a cross-platform CLI and web-based Winlink client. It doesn't talk to the radio, or modulate/demodulate
        audio. For that it delegates to other software.
        Hamlib provides the functionality to change frequency
        Ardop does the actual modulation/demodulation
Ardop
Winlink gateways support quite a few protocols that can be used to connect. Some require expensive proprietary
        hardware, but the one that is of most interest to Linux users will probably be Ardop.
        This is an open standard radio protocol.
        It is apparently open source, but I couldn't find the Linux source for it anywhere, so I grabbed the binary from
        https://www.cantab.net/users/john.wiseman/Downloads/Beta/
    
Install and configure Pat
Install Pat from https://getpat.io. Run pat configure for it to provide an
        example config file which should live in ~/.wl2k/config.json
        Configure the hamlib_rigs section
"hamlib_rigs": {"your_rig_name": {"address": "localhost:4532", "network": "tcp"}},
    You also need to configure Pat to use Ardop:
  "ardop": {
    "addr": "localhost:8515",
    "arq_bandwidth": {
      "Forced": false,
      "Max": 500
    },
    "rig": "your_rig_name",
    "ptt_ctrl": true,
    "beacon_interval": 0,
    "cwid_enabled": true
  }
    Run it all
#You need to find out what number corresponds to your radio's soundcard. Run aplay -l and arecord -l
./ardopc_64 8515 plughw:2,0 plughw:2,0
# Change 237 for the id for your radio as listed in rigctl -l
rigctld -vv -m 237 -r /dev/ttyUSB0 -s 115200
pat http
    
    Now, visiting http://127.0.0.1:8080 should give you the web interface to Pat.
Sending and receiving email
In order to send or receive email, you need to connect to a gateway. Go to https://winlink.org/RMSChannels, and tick the Ardop box.
        Hopefully, you should see some gateways near you. Clicking on one of them will show you their callsign, the
        bands they support, and what frequencies they're listening on.
        Select Connect in Pat, select Ardop, fill in the callsign and frequency, and click connect.
        Hamlib should change the frequency of your radio, and Ardop should start keying between TX and RX and
        transmitting.
        What happens next? I'm not sure. I haven't managed to connect to a gateway yet :)
Update: I have had success in this, and I wrote it up under send and receive email over hf