For sporadic medium-long distance communication over packet radio. 10MHz isn’t too crowded and can be easily used for regional communications (and occasionally long distance) via atmospheric bounce. It also works well at low power and the antenna is shorter than other long distance modes like the longer wave HF bands (20m+).
Sending data by radio is messy, slow, and generally disappointing. Start your journey by reading up on the Aloha system https://en.wikipedia.org/wiki/ALOHAnet.
