@Captain-Crunch
Yes you can imagine how Maintenance Control Felt as the messages started to light up their screens.
These messages would have appeared live on someones workstation
I am aware of an airline that took a HF Datalink for their aircraft as a cost mitigation however it was never activated (to my knowledge)
As for Txing in a dive, possible but the HF uses 3 phase power AC & a coupler so the chances of failure would increase (In my opinion)