AM bands from 2 to 30 MHz have propagation characteristics over sizable geographic areas. FM aka 175 MHz and higher are local only type systems.
A global or nationwide info blockage will be overcome mostly with 7 or 14 MHz bands.
I am terrible, there are meter names for all these that I know not. What 40 and 20 meter I think.
Hmm. EWTN has some shortwave programming. Just learning about that should give us some ideas as to what can be accomplished over 100s of miles range.