The sound of scrubbing an fm radio back and forth across the spectrum. There are bits and pieces of stations picked up with static in-between. Recorded using an old analogue radio, connected to a zoom h1 handy recorder.
I foudd this frequency, between 4450 and 4475 khz whilst going through channels on radiosdr. Org. It sounds a bit like a printer and then lower down sounds like a laser. Sorry for the sound of me pressing the keyboard, my laptop has an internal microphone so this was picked up.
This is a 10-min recording i made with audacity of the mysterious russian radio signal known as "the buzzer". It can be found by tuning the dial of your shortwave radio to 4625khz. The radio station's call sign is uvb-76.