Shortwave spy stations, still transmitting years after the Cold War

I’ve been reading a number of John Le Carré books lately, which are mostly fictional thrillers about Cold War spies. The Spy Who Came in from the Cold is a particularly good one. So in that vein, I’ve been reading about ’60s spycraft, including how they used to communicate.

In the pre-internet days, these spies used shortwave radios to receive orders from “numbers stations”, which are radio repeaters transmitting coded signals over the open airwaves, only at ranges higher than AM and FM music stations. Used together with a “one-time pad”, these encoded transmissions traveled around the world on open airwaves but were unbreakable if you didn’t have the code.

I decided to see if these “number stations” were still around, as I had heard that they are still on the air. Tech seems to go obsolete these days very quickly, so I was skeptical. Short answer, they are still broadcasting!

There’s a whole subculture of people that track these stations and there’s even a schedule that shows expected repeat transmissions. They’ve given them names based on their quirks, “The Pip”, “The Airhorn”, “The Buzzer”, all of these transmit audible sounds when inactive. When they are active, a voice reads numbers or letters from the military alphabet.

They transmit in English, Spanish, Russian, and Morse code, which gives a hint at how widely they are employed. What we don’t know is if these stations are in active use or “mothballed”, though given their level of activity, they’re at least kept in a state of readiness and have been for many years. This may be due to extreme caution on the part of spy agencies: changes in frequency of transmissions or other details might inadvertently reveal operational details. In that vein, as if a carryover from a past era, several of these transmissions are still done manually by radio operators.

Moments after I checked the page above, a station labeled “M12”, for Morse code, began transmitting: “TTT 531 531 531 TTT”. Twenty minutes later, the same message on a different “M12” channel. Who knows what this means? There’s a good chance the answer to that lies behind the former Iron Curtain.