Numbers Stations

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Podcast Transcript

If you ever stay up at night scanning through frequencies on shortwave radio, there is a good chance you might come across something very odd and kind of creepy. 

You will find a station that is nothing but a disembodied voice reading off a seemingly random string of numbers. There is often an identifying sound or song which is played on a regular basis before another recital of numbers. 

These stations have no call signs or other identifying information, and no one has ever publicly claimed responsibility for them. 

Learn more about numbers stations, what they are, and how they work on this episode of Everything Everywhere Daily.

Back in the mid-1990s, I owned a shortwave radio that I would listen to at night. 

At the time, before the internet became widespread, shortwave radio was a window into the rest of the world. Shortwave radio signals can travel vast distances around the world by bouncing off the Earth’s ionosphere, especially at night. 

I could move up and down the dial, picking up any number of stations from around the world broadcasting in different languages. 

However, every so often, I came across something that was very…..weird. I’d find a station that was nothing but someone reading numbers. Seemingly random numbers. 

Sometimes, there would be a sound or audio cue that would break up the numbers before someone started reading them again. 

Listening to these stations was really creepy. 

They seemed to serve no purpose. You’d just listen to someone read out numbers over and over, usually in the middle of the night, because that was when you could get a good signal.

So, the million-dollar question was and is, what were these number stations? 

The very first thing that could be construed to be a numbers station appeared during the First World War. Stations appeared in the shortwave part of the spectrum, broadcasting nothing but numbers in Morse code. 

It was said that Archduke Anton of Austria, who was a child during the war, would stay up listening to these stations, copying down what he heard and sending the Austrian intelligence service. 

Here, I should probably explain why these broadcasts were done on shortwave radio and not on other, more popular frequencies. 

Shortwave radio signals can travel long distances due to their ability to reflect off the ionosphere, a layer of the Earth’s atmosphere filled with charged particles located approximately 60 to 250 miles above the surface. Unlike higher frequency signals (such as FM radio), which typically travel in straight lines and, therefore, are limited by the horizon, shortwave frequencies have the property of being able to “bounce” between the ionosphere and the Earth’s surface.

The ability of shortwave transmissions to travel so far is part of the key to understanding why numbers stations appeared on the shortwave bands and nowhere else. 

When World War II began, more numbers stations started to appear again. There weren’t a lot of them, but they appeared on the airwaves, and they used voices to read numbers, not just Morse code. 

The end of the war saw a reduction in the number of numbers stations, but they came back with a vengeance during the Cold War. The early 50s saw an explosion of numbers stations. 

Dozens of them sprang up, each of which had a different identity. They appeared on different frequencies, they were in different languages, and they had different sound signatures. Each station would usually do something to identify it, often a song or a sound clip. 

Soon, amateur radio operators began to track and name these number stations, giving them monikers based on their audio signals.

It isn’t often that I do an episode on an exclusively audio topic, but this is just such an episode. 

The following is a brief recording of a numbers station which was dubbed the Lincolnshire Poacher. The Lincolnshire Poacher got its name from an English folk song it played at the top of the hour, followed by numbers. 

Here is a clip from the Lincolnshire Poacher numbers station, which was recorded in 2007, a year before it went off the air. 

<insert audio clip>

Other stations were identified, such as The Swedish Rhapsody, The Buzzer, Yosemite Sam, and others. 

There were many theories as to what these stations were. One of the more outlandish theories was that one of the stations was a deadhand doomsday device set up by the Soviets. 

In the event that the station went off the air, it would somehow trigger a nuclear strike. 

The idea was rather ridiculous because putting the fate of the world on a radio station that was subject to atmospheric conditions and electrical outages doesn’t really make sense. 

Sleuths, who cataloged and followed these sites, began putting together what the stations were. 

For starters, none of these stations were identified or registered as all radio stations should be. They were, in effect, pirate radio stations. 

However, unlike pirate radio stations, there was no government effort to close any of these stations down, something which happened all the time with actual pirate radio stations.  

The regularity of their broadcasts and the power at which they transmitted meant that a great deal of money had to be behind them. No one was going to spend that sort of money for something with no obvious purpose. 

It also turned out that it wasn’t too difficult to determine the direction and, ultimately, the location of a powerful radio signal. 

The Lincolnshire  Poacher, for example, was determined to first be broadcasting from Bletchley Park in England, and then it was later moved to a British military base on the island of Cyprus. 

There were other stations discovered in other Western countries, including in the United States and Australia. 

It was also possible to at least tell via the direction of the signal that there were numerous sites in the Soviet Union, the Eastern Block, and Cuba as well. 

It soon became obvious that these stations were part of intelligence operations for various countries. When the locations of transmitters were discovered, they were often immediately shut down or moved to a new location. 

So, if these stations were part of intelligence operations, what exactly were they doing? 

If you remember my episode on cryptography, you can, in theory, crack any encryption system. Very difficult encryption systems developed by the Germans and Japanese were cracked during World War II. Even a very secure digital system can, in theory, be cracked. 

However, there is one type of system that can’t even theoretically be cracked. It is called a one-time pad. 

A one-time pad is the most secure form of communication possible because it is completely random. There is, in effect, no system to crack, which is why it is uncrackable. There is no message encoded in the signal which is sent.

However, such a system requires the sender and the receiver to have a key to understand what a message means. 

So long as the sender and the receiver have the same key, they can confidently send a message publicly without anyone knowing the message. 

Let’s use the example of this podcast. Of the many people who listen to the podcast every day, let’s say I wanted to communicate with just a single person who listens to the show.

Ahead of time, we could agree on a code. I would select an arbitrary number or even a phrase that, if you heard it, would indicate the predetermined message. If we selected our code carefully enough, no one would even know there was a message.

This is a very simple example. You could create an elaborate numeric system that could convey very complex messages. 

If an intelligence service puts an agent in the field and needs to send them instructions, the most secure way to do so is using a one-time pad. However, the agent has to keep the pad secure. Otherwise, they would be compromised.

So, why would they use shortwave radio? 

In the case of sending messages to agents in the field, it doesn’t matter if an adversary knows where the message is being broadcast from. I’m sure every country with an intelligence service knows exactly where the numbers stations originated from. 

What matters is protecting the agents in the field. A shortwave radio transmission can be picked up anywhere. All that is required to pick up the signal is a cheap shortwave radio, which can be purchased almost anywhere. I was able to find a shortwave radio for sale on Amazon for just $10. 

An adversary would have no idea who listened to the signal because the signal is available everywhere. That is what makes the system particularly ingenious and why so many countries use it. 

There have been cases of countries who have tried to jam the frequencies used by numbers stations, but they usually just move frequencies, probably to a predetermined frequency in such an event.

Despite the very public way numbers stations are operated, no intelligence service has ever publicly admitted to having operated one……sort of.

In 1997, an anonymous source in British Intelligence told the London Daily Telegraph that the stations were not for public consumption and they are exactly what you think they are. 

So, they sort of said something without saying something. 

Declassified documents from both the Czech Republic and Sweden have shown that during the Cold War Czechoslovakia used numbers stations for espionage. 

Moreover, there was an espionage case in 1998 of a Cuban spy ring that was busted. They found a spy that was using a shortwave receiver to get messages from a numbers station, which was called the Atención station, based on its sound signal. 

The spy was found with a laptop that was used as a one-time pad to decode the messages. 

The Atención case remained the only time a numbers station was used as evidence in an espionage case. 

When the Cold War ended, the number of numbers stations decreased dramatically. However, they didn’t disappear. 

There are still numbers stations that are broadcasting today. There are many websites that can help you find and listen to them if you have a radio, and there are several software radio websites that you can listen to various frequencies in a web browser. 

You might be thinking that numbers stations are rather antiquated. Wouldn’t it be easier and safer to communicate online?

The answer is not necessarily. You certainly can communicate safely online with cryptography. That, however, isn’t the problem. Even if the communication can’t be read, it is possible to identify the recipient. 

Every sort of online action involves what’s known as an IP address. Given the resources of a state actor, let’s say something like the NSA, it is at least possible to figure out who received a message and get an idea of where they are located. 

Even things like using a VPN or onion routing can still be figured out if you have enough resources. 

However, there is nothing to track with a radio receiver. The only possible evidence would be catching a person with a radio, and even then, lots of people have radios. 

Numbers stations remain one of the most open and public secrets in the world. Anyone can listen to them, but no one knows who their intended audience is. 

The Executive Producer of Everything Everywhere Daily is Charles Daniel. 

The associate producers are Peter Bennett and Cameron Kieffer. 

Today’s review comes listener sparksfire on Apple Podcasts in the United States. They write:


I can’t believe how a podcast can change my life. Yours has. My family is tired of hearing about the facts I bring up every day. Thank you for doing what you do.

Thanks, sparksfire!  I’m always glad to hear when I make an impact on someone. However, in your case, I’m hoping the life change you are referring to isn’t the same thing as annoying your family with facts.

Remember that if you leave a review or send me a boostagram, you too can have it read on the show.