I guess the question there is HOW that forwarding is done. But that may be where my understanding of Nostr is a bit suboptimal -- that may be as simple as just boosting it without needing to faff about with signing. Otherwise, it seems like it'd be a propagation that's done from relay to relay without going through a normal client connection, which is where things get a bit odd. The goal of course being to allow people following the person posting the note to see it, and also not to have one npub belonging to the relay that is just a mostly unsorted pile of relayed content which is harder to selectively follow.

Sorry, I don't know what you mean? It is a standard nostr note. It is publishing to relays, nothing more. A signed nostr note just like a normal client. Nostr relays to prop gate from relay to relay typically. That is done at the client level. There is no such thing as a client that reads a ham radio callsign, nor would a relay use this information.

My understanding was relays don't forward notes to other relays -- only to the client requesting the note. That is where store and forward seems like it would be necessary in order to tie a ham-enabled relay into the broader nostr ecosystem, allowing hams to access nostr as clients without an internet connection. But, it isn't immediately clear how that store and forward would be established while maintaining the structure of notes and their apparent origins. I think I need to do some reading.