*** Thanks to Oliver DG6BCEfor this information! ***
The MagPi Journal #80 contains several HAM Radio project descriptions using the Raspberry Pi.
The download of the magazine is free: https://www.raspberrypi.org/magpi/issues/80/
ESA Education partner Dave Honess describes his SSTV experiences in an tutorial (page 62ff),
several other ham radio projects are described in additional articles.
And thanks to Ciaran M0XTD who assisted Dave on the last mile to his success!