While the use cases for blockchains continues to grow, from tracking product shipments, to exchange of values or 'money' one thing has always hung over the whole industry.
What happens if the internet goes down.
Obviously that would be like turning the power off or the sun going out for many people.
But back before the internet existed, Ham radio allowed people to communicate.
This old tech, is still current and working today.
What is new is the ability to transmit blockchain transactions over Ham radio, thereby 'bypassing' the internet.
Assuming a battery was available, then Ham radio or more spcifically radio waves might provide an interesting way for future blockchain and maybe even internet data transmission.
Time will tell
https://www.coindesk.com/bitcoin-coders-send-international-lightning-payment-over-ham-radio