Well this was odd! Was listening on the 20m amateur band, and I spotted this signal on 14205 kHz USB. Looks a lot like LoRa (FMCW chirps, with different 'phasing' for modulation), but there's no actual LoRa hardware for HF. Signsl was contained within a 3 kHz channel. Possibly someone experimenting? Hopefully it's an open source mode...