Ryan,
in order to have an output signal, make the following settings. If you use an external log program that is installed on the RPi, you will see the additional settings below.
Use SSTV only on an external PC on a laptop, because qsstv doesn't work with sbitx anyway. MMSSTV 1.13 is currently being further developed by a Spanish team, which you can find under the name MMSSTV-YoniQ 1.13.3. This requires an external USB audio card (I use the WB2CBA made by Barb).
Yesterday I managed to make some qso in sstv mode using sbitx and external laptop and the usb audio card.
It was exactly 39 years ago that I first saw an sstv image on the converter I built myself with 39 ttl ic. :-)
I was a little nostalgic.
--
Gyula HA3HZ
HA3HZ