In the early 1970s, amateur radio enthusiasts began picking up strange transmissions on the outer reaches of the spectrum. These shortwave signals, buried between shipping forecasts and commercial stations, would broadcast bizarre music and mechanical voices reading out long lists of numbers. As the Cold War intensified, so did the ubiquity of these so-called numbers stations. No government has ever officially acknowledged their existence, and some can still be heard today. They’re illegal to broadcast and mathematically impossible to crack – but what are they?
Most stations begin their broadcasts with music. The Swedish Rhapsody opens with the distorted jingle of a wind-up music box. The Lincolnshire Poacher plays a synthesized version of traditional English folk song. This is an announcement to the receiver that the numbers are about to begin. These are usually read out in groups of five by a staccato, machine-generated voice, sometimes for as long as 45 minutes. Then the station falls silent until the next scheduled transmission. Some stations transmit the numbers as Morse code, and there have been rare cases of the numbers being read out live.
It isn’t the numbers themselves that are strange, but the oddness of their delivery. Each station has its own idiosyncratic quirks, which seems counterintuitive for something intended to be secretive. They almost urge people to listen in, which has created a subculture of shortwave fanatics obsessed with unraveling their secrets. Oddities include the Tyrolean Music station, which plays recordings of German drinking songs and yodeling. The Gong bookends its numbers with loud, mangled clock chimes. The metallic voice on The Swedish Rhapsody sounds eerily like a little girl.
On a station nicknamed Ready Ready, the announcer puts on a bad English accent, perhaps in an attempt to hide its origin. The nonsensical German on the Tyrolean station (“Helmut greets Franz! The sun is shining wonderfully! Our hen is about to lay an egg!”) has a slight French twang. There have even been cases of numbers stations interfering with air traffic control, and interrupting programmes on the BBC World Service. A live operator was once recorded reading numbers over the machine voice, and The Russian Woodpecker – which transmitted a repetitive tapping noise for over a decade – was broadcast from an array inside the Chernobyl exclusion zone.
Erwin van Haarlem was an art dealer who moved to London in 1975 using a Dutch passport. Described by neighbours as a “pleasant oddball”, he habitually changed the locks on his flat, never had visitors, and rarely spoke to anyone. He visited Russia twice during his stay in the UK and seemed to take an active interest in Jewish dissident groups, which attracted the attention of the Metropolitan Police’s Special Branch.
A surveillance operation was mounted. Detectives monitored van Haarlem’s movements from a house across the street and bugged his phone. During the course of the investigation, £54,000 of unexplained income was discovered across multiple bank accounts. Paperwork was forged to make it seem like the money was coming from his art business, but an accountant saw through the ruse. In 1988, van Haarlem’s home was raided and detectives caught him receiving coded messages using a shortwave radio. Over a period of 13 years he had intercepted over 200 coded transmissions. They were all five figure groups of numbers, tapped out in Morse code. He had been decoding them using one-time pads, which detectives found hidden in hollowed-out bars of soap.
He was a spy, sent to Britain by the Czech government to infiltrate dissident groups and gather information about companies involved in Ronald Reagan’s ‘Star Wars’ program. He was sentenced to ten years in prison and deported to Prague at the end of his sentence, but his real identity has never been revealed. The van Haarlem case is the only direct evidence of a numbers station being used for espionage during the Cold War, and it explains why this method of communication was, and still is, favoured by intelligence agencies. He was able to intercept the messages using a simple, store-bought radio, anyone listening in wouldn’t be able to decipher the code without the appropriate one-time pad, and it could never be traced back to the sender.
After the fall of the Berlin Wall, numbers stations continued to operate – and still do. Cherry Ripe, which is believed to have been British, was live until December 2009. Voice messages were heard on The Buzzer, a station that has operated since at least 1982, in September of this year. Some believe modern stations may be used by drug runners in Latin America or insurgents in war-torn countries. No organisation has ever admitted to a specific broadcast, although the British Department of Trade and Industry told the Telegraph that they’re “not intended for public consumption.”
An archive of numbers station recordings was released on CD in 1997. The Conet Project spans four discs and contains 157 tracks, some of which have been sampled by bands including Wilco, Boards of Canada, and Porcupine Tree. Director Cameron Crowe used clips from the collection to create a feeling of unease in his 2001 film Vanilla Sky.
There’s something inherently fascinating about the numbers stations and the way the surreal, inscrutable nature of the recordings creeps under your skin. It’s no surprise they’ve captured the imagination of so many artists and musicians. Erwin van Haarlem’s arrest may have exposed one station, but hundreds more remain shrouded in secrecy. We’ll never know the truth behind the playful bleeps of The Lincolnshire Poacher or the shrill voice barking out numbers on The Swedish Rhapsody.