On: Snowden's talk at Bitcoin 2019 conference [video]

[brokenmachine]

?how?

50Hz is 50Hz everywhere.

[Ao7bei3s → brokenmachine]

It's never exactly 50 Hz, as the frequency is affected by load and generators can't compensate this perfectly. So record it in many locations, then correlate the signal extracted from audio/video against the database.

Main article: https://en.wikipedia.org/wiki/Electrical_network_frequency_a...