Amateur radio clubs:
The Veron Dutch amateur radio club
Chapter 12, Dordrecht, of the Veron
Raspberry PI links:
KM4ACK build a PI GitHub
KM4ACK on YouTube
DL1GKK Set up a Raspberry Pi for Ham radio
OH8STN off-grid and field radio
OH8STN off-grid and field radio on YouTube
Hardware:
A Radio Interface for Digital Two-Way Radio Applications
Digimodes:
FT8 Operating GuideWeak signal HF DXing for technophiles