On 4625 kHz a monotone buzz drones day and night, broken only by Russian voices reading code words. It is one of dozens of 'numbers stations' aimed at spies no one can identify — and no agency admits to owning.
Shortwave broadcasts of spoken digits, letters or Morse, on fixed schedules since World War I. Thought to send one-time-pad orders to spies in the field — undecryptable by design.
The most famous of them all: a buzz tone repeating ~25 times a minute, 24/7, from sites near Moscow and St. Petersburg. Occasionally a voice cuts in with names and numbers.
A clear modern primer on how these stations work, why they survived the internet, and what spycraft needs that email never could.
The documented cases: real spies — from Cuba to the UK — caught with shortwave receivers and codebooks, proving the broadcasts were no myth.
A four-hour collection of numbers-station recordings released in 1997 — the eerie audio that pulled this hidden world into public ears.
Hours of actual station recordings — children's voices, counting women, synthesized tones. Listen once and you won't forget it.
The hunt to locate one of the most famous Western stations — a synthesized English voice named for the folk tune it played before reading numbers.
An actual recording of UVB-76 still transmitting in 2025 — the same drone that has outlasted the Soviet Union itself.