What open hardware can legally do any useful (open source, auditable, and secure) encrypted voice communication at long distance via ISM?
Of course encryption is not impossible on HF, just a bit more difficult.
Whatever, both commercial and military uses are using encryption on HF.
https://www.wired.com/story/tetra-radio-encryption-backdoor/
This is why proprietary solutions are non-starters.
Civilians deserve real encryption they can control with provable privacy.
Thanks.
The M17 project found some low cost transceivers that operate on a pretty low level, and I think those would be relevant for future development on ISM for people wanting to use encryption.