Running PACKET on Linux

 Hi again everyone!

Man, I cannot put down my Linux with ham radio software! It's absolutely amazing! If you didn't read my last blog post, I got Linux to FINALLY run RMS Express and VARA, albeit with some issue. It does, for the moment, seem fixed. Today, I want to talk about expanding upon the RMS software to run packet for HF, VHF, and UHF radio.

Installing Direwolf

In the 1980s, during the revolution of the personal computer and the digitization of ham radio, packet could only be sent via TNCs. These were boxes that were no different to a dial-up modem. Data would run at a rate of 1200 baud via an FM transceiver. 

Once computer scientists, software engineers, and amateurs figured out that we could virtualize TNCs, we developed software such as Direwolf. To run and install Direwolf, make sure to run the following:

    sudo apt-get update

    sudo apt-get upgrade

Once you've done this, we have to clone the Git repository where Direwolf is hosted. A big thanks to WB2OSZ for hosting it!

    git clone https://www.github.com/wb2osz/direwolf && cd direwolf

Once we clone the repo, we add the command to change directories into the direwolf directory once it's done. Next, let's make a directory and cd into that:

    mkdir build && cd build

Finally, let's set everything up by making an installer for Direwolf:

    make -j4

    sudo make install

    make install-conf

We're done! Now let's set our configuration up...

Setting Up Direwolf

Direwolf comes pre-configured with a config file. To access this, type the following command in your root folder:

    nano direwolf.conf

Here, you can make the necessary adjustments. You'll need to provide your callsign in the NOCALL section and you'll also need to update your sound card address. It is pre-configured to plughw: 1,0. Run arecord -l to list out your soundcard devices. A piece of advice - a USB soundcard is much easier to work with...

Once we're done here, we can set up Winlink to connect to Direwolf. In essence, we're "tricking" the software to believe that we have a physical TNC by setting it to Direwolf's TCP and Port address.

NOTE: The previous steps came from here: https://www.thetechprepper.com/digital-modes/setting-up-dire-wolf

Inside Direwolf, we need to also specify our modem baud rate. For VHF/UHF, it is common to use 1200 baud (standard packet and APRS), while for HF SSB, it's common to use 300 baud (HF packet and APRS). You'll need to uncomment the correct line that corresponds with the frequency band you are on. 

Direwolf, interestingly, has an EAS mode for Emergency Alerts that come across NOAA weather radios. The creator of Direwolf has stressed the importance of converting SAME-encoded messages into APRS messages for local emergencies. This does seem like an excellent idea and an intriguing new way of retransmitting time-sensitive information that could save lives. I'll need to read more on it to see how to use this mode.

Setting Up Packet Winlink

Packet Winlink is quite simple to set up. Follow my instructions below.

First, open Winlink Express and select "Packet Winlink." Then click on Open Session.

Navigate to the Settings tab in the Packet session. You'll be prompted with several dropdown boxes, but don't panic. We need to set our Packet TNC Type to KISS (it stands for Keep It Simple, Stupid) and the TNC model to NORMAL. 

In the Serial Port option, select TCP. Leave the TCP Port/Host address as 127.0.0.1, or whatever the default is, and in the smaller box next to it, type in 8001 (Direwolf should give you a reading of where this port is. Mine happened to be on 8001). 

In TNC Parameters, select 1200 baud. The sub-configurations are of personal choice, like retry attempts. When you're done, press Update.

Now, when you want to use Packet, you'll need to open both Direwolf and Winlink Express. Simple soundcard interfaces, such as the Easy-Digi, can be found online. Schematics are also posted almost everywhere. PTT control can be done with a simple FT232 BoB, but I'll leave all that up to you.

Alongside Winlink, other applications such as Xastir and GridTracker should work well with Direwolf!