Spam was a challenge for self-organized networks almost as soon as they left the university labs, 40 years ago

UHF is strictly line of sight, and finicky HF (which bounces off the ionosphere) might have a total global bandwidth of 15mbit/s during a good hour of a good day. For everyone. If you use the entire possible spectrum.

you don’t need custom anything, you just need to set it up. You can put access points on your roof and on your neighbors’ roofs and on the roofs of buildings on a distant hill, plug them into routers, configure an addressing scheme and routing rules and you’re set.

anybody with a connection to any of those nodes can set up a server and offer content.