I hear shortwave radio stations whi transmit strange signals.
Jammers?
Coded messages?
Sounds like train and ship and bip bip bip.
I hear similar sounds.
http://websdr.ewi.utwente.nl:8901/?tune=6085am
This is interesting
https://www.radiobanter.com/shortwave/41393-shortwave-strange-sounds.html
I also hear wind sound on shortwave frequencies and bubbling.