Relying on HAM radios and satellite links are both legacy systems and we can’t pretend any significant percentage of the global populace could conduct Bitcoin transactions without centralized 3rd party services subject to the same regulations as the banks, much less use HAM radios, especially the poor and unbanked who always seem to be the goto demographic the proponents of cryptocurrency point to as the people benefiting greatly from cryptocurrency.
It’s on par with saying when supply chains fail we have farming, hunting and gathering. Very few people are capable of getting fresh water much less living off the fat of the land.
I like the technology and do see it as still in the early stages of adoption, but I liked the freedom of the early internet, unfortunately that didn’t stop SV and VC money from putting a strangle hold on it, making it the shit-hole sandboxes it is today, exploiting people and farming their attention and data for advertising dollars.
> sent via HAM radio
You probably want to transmit your private key in a secure manner. HAM radio is not a good way to do this: http://www.arrl.org/news/fcc-dismisses-encryption-petition
You are correct in that technically HAM does not allow for encrypted communications, but that's not an issue here, and probably would be very low on the list of concerns in a situation where your only comms channel is HAM.
There are also devices for offline transactions.