Unid 16Kbps/16000 wideband FSK (WBFSK) heard and sent me by my friend Martin on 31875 KHz, just a bit beyond the limit of the HF region (LVHF). announcement in Figure 1 the sharp filtering at the edge of FSK transitions.
The signal has strong 196 ms ACF spykes which are due to the inserted bursts limiting the blocks in which the transfer is arranged (Figure 2).
The bitstream resulting after demodulation of part of the signal has a 3136-bit dimension framing, as expected since the 196 ms ACF, consisting of a 191-bit known series (the above mentioned inserted bursts) followed by 2945-bit of unknown data; the inserted burst are most likely utilized for (re)synchronization purposes. Despite respective runs, I did not find a valid LFSR for that sequence. besides note - zooming the bitstream - further 33 bits that could not be part of the following data block: this way it could be a 192-bit series followed by a 32-bit CRC... but it's only a mine speculation!
Voice or data? The 16 Kbps velocity and the way it sounds (like a white noise, to make it hard to intercept) make me think of a vocoder. Indeed, in many VHF radio stations the analog speech signal is converted into digital form utilizing CVSD (Continuous Variable Slope Delta)  just moving at 16 kbit/s and then encrypted most likely utilizing a VINSON household crypto device specified as KY-57/KY-58 .
L3Harris RF-7800H-MP could be a possible candidate among another radios since it allows both VHF WBFSK and CVSD vocoder.
Likely, the 191-bit (or 224-bit) inserts are not a CVSD circumstantial feature but are added by the crypto device.