This is not a radioberry issue but a linux related one.
A lot of people are having problems to get this running..... iam thinking of making an image or is there an image we can add the radioberry?... do people have ideas what must/should/could be installed.
You need to run a virtual audio card program. In linux this is a module (driver) called : snd-aloop .
This module must be loaded. For loading a module a program modprobe is available..
sudo modprobe snd-aloop but you can add some parameters:
sudo modprobe snd-aloop enable=1,1 index=4,5 id=vac1,vac2 pcm_substreams=2,2
This is all described in the instructions in the attachment.
The other pictures show wsjtx running with pihpsdr.
Hope this helps.