I run FreeDV on HF.
https://freedv.org/
https://qso.freedv.org/
https://evoham.com/
https://www.arrl.org/files/file/QST/This%20Month%20in%20QST/2023/090%20September%2023/09%202023%20Brodsky.pdf
https://www.sigidwiki.com/wiki/FreeDV_plus_Video
https://vk3tbs.home.blog/2025/08/23/freedv/
https://gadgeteer.co.za/hamradio/freedv-hf-digital-voice-for-amateur-radio/