Category Archives: Numbers Stations

How to decode that RDFT in numbers station HM01? Roland explains

DIGTRXA few weeks ago, I published a post with a recording of the Cuban numbers station HM01, a “Hybrid Mode” numbers station which interchangeably broadcasts both voice and a digital mode called RDFT with each transmission. I had suggested using an application called “DIGTRX” to decode the data bursts.

I then received  a comment on that post from the author of the DIGTRX program himself, Roland. He has actually created a page in English which describes in detail how to decode the RDFT in HM01.  Note that this page was originally in Roland’s native Portugese, and he kindly translates it into English for us: http://www.qsl.net/py4zbz/eni.htm

[While this means that we can decode the transmissions, it doesn’t mean we can necessarily decipher them, however.  At least, not yet.]

Imagine that a spy numbers station is using an application you, yourself, authored to send coded messages. What are the odds?  This apparently happened to Roland, when he discovered that HM01 was, in fact, using his application DIGTRX. What?!?

Actually, it makes sense to me that numbers stations would use DIGTRX. After all, it’s open source. Operatives in the field can download the application without raising awareness. If it were a proprietary application, either commercially or of their own design, it would add to the complication of downloading and using it (on both ends). As you’ll read in Roland’s tutorial, HM01 has built in robust redundancies by using RDFT and DIGTRX. Very interesting.

Thanks, Roland, for sharing!

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Numbers stations: stranger than fiction

towersMore mentions of numbers stations in the popular press, thanks to the new movie, The Numbers Station. Hat tip to SWLing Post reader, HK:

(Source: Reelz.com)

[…]If you ever find yourself wishing your life was filled with a little more mystery, a little more excitement, save up thirty dollars and go buy a shortwave radio and start scanning the airwaves. With a little luck and a lot of patience, you might come across a band carrying the monotone voice of a man reciting military call letters (“Echo — Kilo — Charlie”), the robotic voice of a woman counting in Russian, or one broadcasting a continual string of beeps, chirps or hums. If you manage to tune in to one of these stations, you could very well be listening in on a coded message intended for a spy.

Once thought to be useless for communications purposes because of their high frequencies and short wavelengths, shortwave radio bands were, it was discovered in the 1920’s, ideal for sending messages over extremely long distances. Shortwave signals are broadcast into the sky, where they are reflected or refracted off of the electrically-charged ionosphere layer of the upper atmoshpere and sent back down to Earth as far as a continent away. By the start of the Cold War a few decades later, countless shortwave radio stations were found to be broadcasting strange, seemingly coded, messages using this technique. At the time, these so-called “number stations” (or “numbers stations”) were widely believed to be in use by various government intelligence agencies to broadcast secret messages to spies over great distances, but none of the codes — if, indeed, that’s what the signals were — were ever cracked and no governments ever officially acknowledged their use.

Number stations remained a mystery and were all but forgotten by the general public until the discovery in the ’70s of a station that was broadcasting a powerful signal comprised of the synthesized voice of a British woman speaking a sequence of five numbers. The station came to be known as “The Lincolnshire Poacher” because two bars from the English folk song of that name served as interval signals. The signal from the station was traced back to the Royal Air Force base at Akrotiri, on the island of Cyprus, providing number station enthusiasts with the first “proof” that government organizations like the British Secret Intelligence Service were behind some, if not most, of the number stations.[…]

Read the full article at Reelz.com. Keep track of news on numbers stations and our recordings by following the numbers stations category.

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Shortwave Radio Recordings: Listen to Cuban Spy Numbers Station HM01

WFL_015Numbers stations have always been a dark oddity that pop up from time-to-time in the course of shortwave radio listening. There is unquestionably an air of mystery and intrigue which surrounds them. With the release of the movie The Numbers Station, many non-SWLers may be enticed to explore the HF bands.  A good thing, as it may draw fresh interest to this classic radio hobby.

I have heard numbers stations since I first started listening to shortwave radio broadcasts some thirty years ago, and I find that I often pause to listen (and to wonder) when I come across one on the bands.  The numbers station I hear most often, though the country of origin cannot be confirmed, is in Cuba–well, at least, we’re pretty certain of that. The same female voice, reading numbers in Spanish, has been Cuba’s calling card in the spy numbers world for some time.

Two weeks ago, on a Sunday morning between 10:00-11:00 UTC, I captured the Cuban spy numbers station widely recognized as HM01 (Hybrid Mode Number 01) on 5,855 kHz. HM01 broadcasts a mixture of AM voice and digital file transfer modes intermixed within the same transmission. The voice heard is the familiar Spanish female voice described above; the digital portion of the broadcast uses a mode called RDFT, a differential phase shift keying mode that has never become popular or standard in the ham radio world. If you’re feeling adventurous, the Windows software DIGTRX (download here) can decode RDFT.  Let us know what, if anything, you discover…

You can click here to download the entire HM01 broadcast as an MP3, or simply listen via the embedded player below:

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Finally: Official trailer for the movie The Numbers Station with John Cusack and Malin Akerman

The long-awaited trailer for the new movie, The Numbers Station:

We first mentioned the The Numbers Station in 2011, when it was still being filmed.

In this film, John Cusack’s character, Emerson, has been given the task of protecting Katherine (Malin Akerman), the operator of a shortwave numbers station that broadcasts encrypted messages to operatives. When the station is compromised in a surprise attack, they must work together to secure it and prevent distater.

According to the website The Digital SpyThe Numbers Station is scheduled for release in the US on April 26, though a UK release date has not yet been confirmed.

If you’re new to shortwave radio and wish to listen to numbers stations, follow the category Numbers Stations–we will post updates on the movie as well as several recordings of real numbers stations still in existence.

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Deutsche Welle: spies received secret messages on their shortwave receiver

towersIf you’ve ever been curious who listens to and acts upon the coded messages we hear in numbers stations (a.k.a. spy numbers stations), follow this German-based couple who are being accused of spying on NATO and and the EU:

(Source: DW)

A spectacular trial at a Stuttgart court is about to begin, involving a German-based couple accused of spying on NATO and the EU for decades on Russia’s behalf. Neighbors say they knew something was fishy.

It reads like a John le Carre novel: “dead mail boxes,” secret radio signals, encrypted messages hidden in plain sight on the Internet.

According to accusations, a married couple has been spying in Germany for more than 20 years – first at the behest of the Soviet Union and thereafter for its post-Soviet incarnation, the Russian Foreign Intelligence Service.

On Tuesday (15.01.2013) 54-year-old Andreas Anschlag and his 48-year-old wife, Heidrun, will stand trial in Stuttgart. Federal prosecutors accuse them of “secret agent activity” and of “forgery of documents.”

[…]The history of the purported agent couple begins at a time when the Soviet Union still existed and the Cold War was still cold. According to accusations, Andreas Anschlag traveled to West Germany in 1988 with the help of a forged Austrian passport. His wife did the same in 1990. Both were supposed to have been born in South America. The two settled in Aachen, close to the western border with Belgium, where Mr. Anschlag studied mechanical engineering.

[…]The files were delivered via “dead mail boxes,” according to official charges, to the Russian Foreign Intelligence Service in Moscow. The couple apparently received further commands through an agent radio network and sent their own messages via satellite and through an internet video platform.

When they were arrested in October 2011, the German news magazine Der Spiegel reported that the woman was sitting in front of a shortwave receiver, writing down secret messages. At that point the pair was living in a house in Michelbach, a small community in the German state of Hesse.

“Suddenly we had this spy thriller taking place right outside our window – it was better than the movies,” one of the neighbors told DW.

Read the full article on DW’s website.

Note that this story reads much like the Russian couple who spied on the US a few years ago.

 

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Coded message from WWII carrier pigeon structured like numbers station communiqué

The message contains the all-too-familiar 5 character groupings we’re used to hearing in numbers station broadcasts

This news story about a recently discovered WWII carrier pigeon message has been floating around the Internet over the past few days.

(Source: CNN)

Not even the British spy agencies that inspired James Bond can solve the mystery of a secret World War II message recently found on the skeleton of a carrier pigeon in a house chimney.

The meaning of the encoded message apparently died about 70 years ago with the wayward pigeon that David Martin found in his smokestack in Bletchingley, Surrey County, England.

Martin recently discovered the bird’s remains with the surprisingly intact message inside a small red canister attached to a leg bone.

[…]Hand-written on a small piece of paper labeled “Pigeon Service,” the note consists of five-letter words. Those words don’t make sense: The jumble begins with “AOAKN” and “HVPKD.” In all, the message consists of 27 five-letter code groups.

Indeed, the only hope the UK intelligence agency, the GCHQ, stands in deciphering the message (click here to see the full message) would be to find the appropriate, specific decipher key. Most likely, this message–like numbers station (a.k.a. spy numbers) messages–was a one-time communiqué, with a one-time decipher key. This type of encryption is incredibly effective as they provide little to no context for deciphering.

But again, that’s a part of the magic and mystery many of us find so fascinating about numbers stations.  The messages are (still) everywhere and broadcast publicly, yet, we have no clue of the meaning.

If you’ve never heard a numbers station, check out this audio of the numbers station, “The English Man” I recorded earlier this year:

Also, you should check out the many numbers station audio files in the Conet Project on Archive.org. Listen to a sample in the embedded player below:

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Numbers Stations: The English Man came back

Two weeks ago this Friday, I caught and recorded the numbers station often referred to as the English Man. He was found in the pirate radio watering hole (of 6,925-6,990 kHz) on 6,949 kHz.

After sifting through more spectrum recordings taken the following evening by the Microtelecom Perseus, I realized that I caught him once again at the exact same time and frequency. I have his full transmission in the recording below.

Note: The English Man was broadcast in AM, but I had to dig the signal out of the noise. I used a tuning technique I referred to last year in a post–click here for more info.

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