Category Archives: Shortwave Radio

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!

VOA protests jamming of English service to China

voa logo(Source: VOA)

The Voice of America is protesting new jamming of its English broadcasts in China.

VOA Director David Ensor condemned the new interference and said the U.S. government broadcaster is working with experts to determine the precise origin of the jamming. He said “the free flow of information is a universal right and VOA will continue to provide accurate and balanced information on platforms that can reach audiences in areas subject to censorship.”

The U.S.-funded VOA is not the only victim of jamming. The British Broadcasting Corporation said this week its shortwave English radio broadcasts also are being jammed in China.

The BBC said that while it is not possible to know who is doing the jamming, “the extensive and co-ordinated efforts are indicative of a well-resourced country such as China.”

VOA broadcast engineers say Radio Australia also is being jammed.

At VOA headquarters in Washington, engineers say that while the agency’s Chinese-language broadcasts are routinely jammed in China, its English broadcasts usually are not. They noticed the jamming of the English programs about a month ago and say it appears to use a new technology.

Many countries have used various methods to jam VOA broadcasts for decades, especially during the Cold War when VOA broadcast heavily into the former Soviet Union and other countries under Communist control. Now, its Persian satellite television broadcasts into Iran are frequently jammed, as are VOA Horn of Africa broadcasts to Ethiopia.

Note our previous article on the topic of harmful interference from China.

Shortwave Radio Recordings: Voice of Greece

TheParthenonAthensFor your listening pleasure: two hours of music, and a little Greek commentary, from the Voice of Greece.

Recorded on February 24, 2013 at 00:00 UTC on 9.42 MHz.

Click here to download the MP3 of the recording, or listen below:

Frank hears Bureau Met in DRM

drmlogoFrank writes:

Hello Thomas,

This afternoon I came across ‘Bureau Met’ on 5960 [kHz]. I have been listening since 0800Z today, 24th Feb. SNR is a constant 19/20dB (RNZI peaks at about 17 on a good day. ). Content is a speech by Martin Luther King, ‘ one small step for mankind’, a speech by Churchill, more Apollo mission, Bill Clinton apologizing to the nation, and similar stuff repeating about every 40 minutes..

I suspect this is a Radio Australia test tx from their Canberra transmitter.

No station ID on the hour.

Cheers
Frank

Thanks, Frank! Has anyone else caught this DRM broadcast?

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.

Pirate Radio Recordings: Wolverine Radio

Wolverine1

Wolverine Radio eQSL–one of two SSTV images decoded near the end of the broadcast

For your listening pleasure: 2 hours and 46 minutes of pirate radio station, Wolverine Radio–recorded Sunday, February 17, 2013 around 2:40 UTC.

Wolverine was broadcasting on 6.925 MHz in the upper side band. Typical of Wolverine, lots of music variety which spans the decades, and no commentary other than station ID throughout.

I decoded two of the SSTV images Wolverine transmitted; the Canadian flag (see right) and this one. You can easily decode these live, or via the recording below. Per Ragnar’s suggestion, I now use MMSTV to decode SSTV images.

Click here to download the full recording of Wolverine Radio, or simply listen via the embedded player below:

Daniel shares recent QSLs

Daniel (W3DI) writes:

I have been enjoying some shortwave broadcasts recently and received some nice QSL cards. Wanted to share the cards and some station information.

 Deutsche Welle - copied broadcast on 15,275 KHz - Jan 20 , 2013 at 1930 UTC

Deutsche Welle – copied broadcast on 15,275 KHz – Jan 20 , 2013 at 1930 UTC

China Radio International - copied broadcast on 9,580 & 6,020 KHz - Dec 29 & 31 , 2012   at 0130 UTC

China Radio International – copied broadcast on 9,580 & 6,020 KHz – Dec 29 & 31 , 2012 at 0130 UTC

IMG_0002

VOA -  Africa service - They sent not only a QSL but a beautiful 2013 calendar.

VOA – Africa service –
They sent not only a QSL but a beautiful 2013 calendar.

Daniel addeded:

Shortwave listening was my first step to becoming an amateur [radio operator]. First receiver was a Lafayette HE – 10 with a Q mulitplier I built. Now using a WinRadio 313 – things have really changed.

Shortwave listening was also my first step to becoming a ham radio operator. The Lafayette HE-10 is a beautiful little 9 tube radio. I love the split dials on the front–much like the venerable Hallicrafters S-38.

The Lafayette HE - 10 (Photo: RigPix.com)

The Lafayette HE – 10 (Photo: RigPix.com)

Halli-S-38

The Hallicrafters S-38 (Photo: The S-38 Guy)