Faraday cage.....a clue, hmm.....
For post apocalypse operations, the FCC rules would seem to be unimportant. How about a spark gap transmitter and a crystal receiver for ultimate simplicity and ease of repair. Probably aren't a dozen components together.
p.s. You could leave them out on the shelf for ready operations. No Faraday cage required.
p.p.s. Remember to ground your cage.