Revision 1 as of 2013-02-13 19:19:14

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WSJT Setup

The wsjt package is used for weak-signal amateur radio communications.

Configuring Audio Devices

Wsjt allows configuration to select your sound card device, but there is insufficient information presented in the GUI interface to troubleshoot problems.

Start wsjt from a command line, and during startup, a list of all available audio devices will be printed. You can then select a device number from the "Audio Device" column, and enter it in the setup dialog of wsjt.

After changing the configuration, you must restart wsjt for changes to take effect.

Known Issue with audio sample rate

Wsjt requires that the audio stream be opened at a single, fixed sample rate. If the Audio device does not support that sample rate, wsjt will fail with the following error:

Error opening input audio stream.
        Errortext: Invalid sample rate
        Number: -9997
Error opening output audio stream.
        Errortext: Invalid sample rate
        Number: -9997
Error  3 in JTaudio, you will only be able to work offline.

In order to provide a resampled audio stream that can support the rate requested by wsjt, you can create a .asoundrc file in your home directory, and add the following to it:

pcm.SignalLink-USB {
        type hw
        card 1
        device 0
pcm_slave.SignalLinkIn {
        pcm SignalLink-USB
        rate 44100
pcm.SignalLinkOut {
        type rate
        slave SignalLinkIn

Once you create this file, you'll have to restart the pulse audio system:

sudo service pulseaudio –restart

Now, reconfigure wsjt to use the audio device named "SignalLinkOut", and it should work. (Thanks to LarryJ2 for documenting this workaround.