That signal almost sounds like you could make a clock from it. Like you manually set it and it syncs to beat in the video.
The "clicks" are second markers, and the low-frequency hum that follows each click encodes a single bit of a binary datastream conveying the current time. If you've ever had an automatic clock in the US, it sets the time by tuning in to WWV and decoding this signal.
It broadcasts on longwave rather than shortwave and uses a different modulation.
https://www.nist.gov/pml/time-and-frequency-division/time-di...