It seems that the US have tested HF radio as a means of long-distance communication of speech and data. Maybe they have realised that satellites and fibre optic cables are not as safe as they thought.
Satellites are easy to take out as the Chinese demonstrated a while back. There was also a report in the UK press recently about the vulnerability of underwater fibre optic cables.
It is interesting how things go around in circles. It is only ~30 years since the UK closed its point-to-point HF radio system. Now we are looking at HF again for strategic communications. It will be interesting to see what happens.
See the full article here