Numbers Stations: The Truth Behind The Code

First Published: March 18, 2012 Last updated: April 1st, 2018 Written by Ian Stephens Estimated Reading Time: 12 minutes 1 comment

Listening intently to a steady stream of static, suddenly you hear a series of low tones followed by a robotic woman’s voice:

“Yankee… Hotel… Foxtrot… Yankee… Hotel… Foxtrot… Yankee… Hotel… Foxtrot…”

The static continues as a sheet of white noise in the background. The woman continues:


These strange series of words and numbers are not the crazy ramblings of a demented person. They are actual broadcasts from real “numbers stations.”

Numbers stations are shortwave radio transmitters that send out a constant stream of numbers, letters, words or song lyrics, all delivered by disembodied voices. The voices are male and female, young and old.

The voices are also typically recorded or, today, synthetically created using computer software although it wasn’t uncommon for radio stations to have an actual live reader instead.

The actual phenomenon of numbers stations are nothing new, and have been around since the end of the Second World War and were at one stage used as a means of transmitting weather during the war itself.

Additionally, they were also used to send covert messages that the opposition – were they ever to pick up on the message – would never understand what is actually being spoken about. It’s a subject that seems to attract a fair amount of publicity, for a wide spectrum of reasons.

For a start, the mystery of the actual reasoning for these stations is still something that is debated today. While it’s never been confirmed that they were used as a part of long-term military strategies, either, so it’s also pretty hard to know for sure just what these services were ever actually used for.

Radio Tower

A radio tower, possibly used for broadcasting numbers stations.

To many laypersons that hear number station transmissions for the first time, they sound eerie and distant, as if from a barren, lonely post-apocalyptic future. For governments and others that need to transmit messages to their agents in foreign countries, however, they are extremely valuable.

For example, one of the most well-known number stations was the Lincolnshire Poacher which was presumed by the run by the British SIS, giving it that very “Bond” feeling and really adding to the overall spectacle and style of the original idea of numbers stations. To a first-team listener to these messages, it would be easy to think that you have hopped back in time such is the cryptic and garbled style of just about every numbers station.

How Numbers Stations Operate

Number stations, sometimes called One-Way Voice Links (OWVL) broadcast a series of loops of numbers or letters. Inside the string of seemingly nonsensical characters is a code which, if you have the decoding mechanism, delivers secret messages across borders and long distances to foreign agents (spies).

As you can imagine, this type of powerful technology was one of the most powerful assets around at the time of its creation. Whilst today we could easily send the information securely via IP messaging or any number of ways, back then you had either radio contact or very basic telephone support.

Having access to this kind of technology back in the day would have been like having a whole new upper-hand on the opposition. If you want to try and find a simple to understand example of what numbers stations were like, you need only look at Morse code – it effectively sent large spans of Morse code across a radio station.

The majority of number stations operate on shortwave radio. This is because shortwave has characteristics that make it easy to send a signal extremely long distances. Although different types of transmission equipment have been used, a regular shortwave transmitter anywhere from 10 kW power to 100 kW is the most common form.

Obviously, this would have been very important for the overall depth and development of the spies own ability to get things done. if cryptic messages had the capacity to travel as far as possible, even into enemy lines, then spies had a far greater chance of accomplishing their original task or adapting to any changes that may have occurred along the way. Without this kind of support, many espionage missions from the Second World War onwards would have gone awry.

Even though spies have access to high-tech modern equipment, many governments find it advantageous to continue to use old-fashioned shortwave radio. It raises less suspicion than a bank of expensive high-powered equipment. Shortwave radio is also better than modern conveniences like cell phones and e-mail because it does not leave a digital trail.

Even today, this hardware is still used across the globe – it makes perfect sense, too. It’s far more likely that somebody would totally miss a random radio signal today, or that they would never even look in the first place.

If we are all so busy checking our e-mails, SMS messages and everything else then many other traditional communication styles have been pushed to the side, meaning that even in this era of technology cryptic numbers stations still exist. Because everything is tracked digitally today, it’s much easier to remain truly under the radar if you use this style of radio transmission because very few people will be analysing or looking for information this way.

Recording of a German Numbers Station

Below is a recording of a German Numbers Station dubbed “G06” or “G6” at 4792KHz on Dec 11, 2009 at 19:36 ZULU time.

Aside from the fact it’s clearly in German, and anyone without a fluent and strong understanding of the language would be lost, the actual content of the message is completely nonsensical – to us. To somebody, though, that message meant something and was genuinely used for some kind of operation or to pass on a message.

German Spy Numbers Station G06 4792KHz Dec 11, 2009 19.36z


Consistent Format

Number stations usually follow a consistent formula. Most broadcasts take place at the beginning or the bottom of an hour. Very often, the beginning of a broadcast will have a “signature” identifier or slogan—perhaps a saying or phrase; or clip of music, sounds or tones.

This was very important so that those who were supposed to hear the message would be able to spot the “tell” that this was the message they were looking for. In much the same way that you see undercover officers using a codeword when wired up to call for support, this was a way to alert only specific people to what they needed to hear.

The reason they also chose the beginning or end of an hour is that they were the most likely times it would be possible to actually get a hold of a radio, and listen out for the specific message.

Usually there is only one message per each transmission. Just as the sign-on has a signature, sign-offs also have some sort of theme. For example, they may say the word “end” or repeat a series of zeros. You might also hear another snippet of music or sounds.

Again, this is so that the individual who is supposed to hear the message can know that what they heard was definitely aimed at them. The importance of having these themes – whether it was music, a sound or a series of numbers and words – should not be lost on anyone.

It was an incredibly important part of preparing and relaying vital messages across battlefields and behind enemy lines to those carrying out espionage missions. Even today, it’s still a very important form of communication as its simplicity still prevails even today.

Number stations are broadcast out in the open but they don’t make any sense to most people. Some officials think they are nothing but a campaign of disinformation by governments to throw adversaries off their trail.

This is a common conspiracy theory across many different forums and styles – people like to believe that the government pull tricks like this on a regular basis to throw people off the scent. It’s been proven in other forms of communication that this can be the case in many different industries, so it’s hardly inconceivable that such tactics have been used in the past.

Because the messages can be relayed together in the open, it’s easy to catch someone and have them believe they’ve broken enemy transmission. The problem is that only a few individuals will have a clue what these messages actually mean!

High Profile

Some number stations operate for years, and throughout those time frames they can tend to pick up various different quirks and nicknames that those who have come across the message will attribute to them. for example, some of the most popular number stations have been:

  • One of the most famous, “The Lincolnshire Poacher,” was never acknowledged by the British government although it operated day and night for decades. Its name was based on the fact that they played the first two bars of the folk song, “The Lincolnshire Poacher,” for each string of numbers.
  • Magnetic Fields” is named after the multi-million selling 1981 album from French electronic musician Jean Michel Jarre. Before and after each set of numbers, the “Magnetic Fields” station played a Jean Michel Jarre track.
  • A Spanish-speaking numbers station emanating from Cuba began their transmissions with the declaration “Atención!”
A WWI Submarine Radio Receiver

A WWI Submarine Radio Receiver

Number stations have been around since World War I. One of the original uses was for countries to communicate with their spies working in foreign countries undercover. Many number stations broadcasts are encrypted with a one-time pad. A one-time pad is a type of encryption method that has a key that is used once and never again. They are considered unbreakable.

Suspected Uses

Numbers stations have been used by criminals like smugglers to help transport illegal contraband such as drugs across borders. It is widely believed, however, that most number stations are run by governments to communicate with agents. Further evidence of this is that most number station broadcasts are in the part of the shortwave band set aside for international use. This band is not available to most citizens that might contemplate using them for criminal activity.

It’s these small hints throughout history that give us more ideas that the usage of numbers stations isn’t for crazy people and criminals alone – there definitely has to be some kind of official, government footprint across these stations. The issue is that they are used across the globe, so it looks to have become a mainstream choice for those looking to not get caught regardless of which side of the fence they are on.

The first official public accusation of using number stations to transmit information to spies was the “Atención!” station of Cuba. A United States Court espionage trial came after the arrest of several Cuban spies in 1998. Prosecutors in United States said they were decoding numbers that came over the “Atención!” number station.

This was one of the big cases to ever be revealed about number stations, despite the fact they had been used for more than four decades prior to this discussion ever taking place. This is a sign of just how effective and useful these systems were in the first place. In fact, it probably does not help the government storyline that they stated they were now decoding numbers – what made them think of trying that, we wonder?

The FBI went to one of the accused spy’s apartment in 1995, gathered computer decryption equipment, and used it to decode their messages. During the trial, the FBI translated some of the spy messages.

The content of the messages were quite interesting, and showed you just one scope of what one nonsense translation can actually turn into when used properly and when it’s been understood to the highest possible standard. Here is one example:

“Under no circumstances should agents German nor Castor fly with BTTR or another organization on days 24, 25, 26, and 27.” 

“BTTR” represents the organization Brothers to the Rescue, an anti-Castro group. (Miami New Times Feb 01) It’s this kind of hint that makes it much easier to believe that the governments around the world have, at one stage, put coding like this to good use either to fool the enemy or to help instruct an agent behind enemy lines.

After all, if Cuban rebels were using them in the late 1980s it’s a cert that the government at least toyed with the idea of using a system like this!

Conet Project

Perhaps the largest collection of number stations transmissions has been gathered by The Conet Project. They have assembled assorted transmissions onto CDs. The recordings have also been made available for free download for the non-profit use of the general public.

Obviously, these messages are of huge public importance as more transparency is something that we all wish to see from our governments. The problem is that without the right way of decoding these messages it would be nearly impossible – the Conet Project makes it much easier to actually get ready-decoded equivalents of these audio artefacts.

They could be talking about anything at all, and being able to actually gain access to something like this can be a great learning experience for anyone whether it’s for media training or for learning about decryption!

Despite this, the band Wilco used several of the transmissions for a music album without permission. They were subsequently sued and eventually decided to settle out-of-court. They paid for the commercial use of the transmissions as well as legal costs.

The Conet Project recordings have been used by noted music groups like Boards of Canada and Faith No More, and in commercial films like Vanilla Sky. It’s managed by someone with a deep interest in the idea of numbers stations, Akin Fernandez, and has released up to five CDs so far with various recordings believes to originate from government orders to espionage agents and other members of their forces elsewhere in the world.

Interference and Jamming

Interference and jamming of number stations takes place. Even though the stations are on open frequencies, jamming is somewhat difficult due to the limited number of transmitters available that are capable of jamming a transmission.

As you can imagine, successfully locking down a radio station is hard work and takes a considerable amount of skill, technology and manpower to successfully manage. Therefore, back in the day outside of just shooting down radio towers there was no real way to just jam a radio station. This meant that, at one stage, radio jamming was rarely used as it was simply unfeasible and this allowed both Axis and Allied forces to carry out many acts of espionage without repercussions.

Nonetheless, there have been interferences recorded over the years. As we know, when there is a will there is a way and with government espionage they’ve been able to jam various broadcasts in more modern times as radio jamming technology has become more common:

  • North Korea interfered with the Lincolnshire Poacher station in 2006.
  • One dangerous jammer affected critical aeronautical transmissions in the Caribbean in 1990.
  • A West German based numbers station interfered with Radio Moscow broadcasts.
  • The Mossad station Uniform Lima X-ray clashed with the “Independent Voice of Zimbabwe” broadcasts.

A number of large jamming sessions took place in 2005 and 2006 from what is known as the “Chinese Music Station,” which emanates from the mainland of China.  Many suspect it was an attempt to jam the broadcast of a Taiwanese station named “Sound of Hope.” There were no spoken numbers or letters as in a traditional numbers station broadcast – only a cacophonous mixture of music, songs, sounds, drums, and flutes. (IARU Region 1 report)

The unique style of the messages sent across this radio station has garnered more mainstream media attention than others in the past, as it’s unique style of producing the sound made it much more difficult to ever be able to trace or track – number codes could potentially be deciphered if given enough time and effort, but how do you decode music and sounds?

There have also been reported jamming’s of the Lincolnshire Poacher station in the 1990s, the CIA station “Cynthia,” and the Mossad station “EZI 1.” Additionally, there may be many more that aren’t so widely reported – as one of the most publically hushed and out-of-sight methods of passing along information it would be no surprise if regular attempts on number stations occurred.

After all, are you going to let a spy wander free if you know that their main method of communication and learning could potentially be a totally free-to-air radio broadcast that passes along information only they can understand? Number stations aren’t just some kind of rarely used idea; they are genuinely a big part of setting up effective and professional espionage missions.

Fringe Radio

Despite jamming attempts, interference, arrests, and various different trials over the years, numbers stations continue to survive. In a fast-paced, high-tech modern world, their low-tech, low-profile nature has worked to their advantage. It’s hard to believe James Bond may be getting his next assignment from a simple shortwave radio, isn’t it?

However, that may very well be the case. As technology advanced at a dizzying pace, it’s hard for people to keep making defences against all of these tools across the years. The big issue for most countries, though, is the fact that for every new piece of technology they defend against an older idea will have been improved and refined to deliver an even stronger response in the future.

Fringe radio, therefore, has become the best way for people to pass along information to only a very select collection of people. While the message might come across a absolute nonsense to others, to somebody out there it could be the security key to unlocking something that would change the entire world. Defending against this kind of system is hard, too, because there’s nothing to say that a message that comes across the radio in total gibberish is some big government plot.

It could be people messing around, it could be illegal activity going on at a civilian level – the possibilities are pretty much endless when it comes to what number stations could be used for in the long-term. Therefore, defending against them becomes something that many countries actually struggle with – how can you shut down the public radio waves? You can jam them, sure, but it’s not something that many countries would ever be too keen to admit.


Nobody knows for sure who is transmitting the eerie, robotic numbers and letters across cities, towns, and borders into foreign countries. Many assert they are government agencies communicating to a far-flung spy network, or simply trying to outwit a rival country’s espionage effort. Others believe drug smugglers have learned to use technology to move their product.

It’s something that literally anyone could do, though, if you have the right technology behind you. you could be leaving messages for people to find for generations to come, and if you work hard enough at it you might just have a team of government agents working around the clock to decipher your message!

It’s a technology that many of us will have thought of, presumed existed but was no longer used. After all, you aren’t likely to send a radio message if you can just use something far more secure and worthwhile and ensure the person hears the message, right?

Well, the thing with number stations are that they give the user the chance to really be explicit in their message knowing that a handful of people, at most, understand what the message really means!

While it’s likely that nobody is ever going to hold their hands up to this kind of activity, All we know for sure is they will continue to send their eerie message across the void as they have for years,“5,2,8,4…6,2,9,7…4,1,6,2…8,8,5,3…”

About Ian Stephens

Ian Stephens is an editor and writer for UFO Insight. He has a keen interest in the fields of strange phenomena, UFOs and aliens. He is also interested in space, physics and science in general. Writing for over 10 years in these fields, Ian has a lot of experience and knowledge to share.

Ian has written a total of 95 articles for UFO Insight. You can contact Ian via email.

1 Comment

  • Inner circle says:

    Awesome very interesting :/

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