Yearly Archives: 2013

Bill helps with low-power, license-free broadcasting

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HobbyBroadcasterIn reference to our post, Dave’s FM Station Empire, SWLing Post reader Bill writes:

Nice article on the use of low power broadcasting. For the last 5 years my site, HobbyBroadcaster.net, has been helping radio enthusiasts along with schools and businesses learn how to use legal, low power, license-free Part 15 radio for a variety of uses. I created the site due to my involvement with starting a campus-limited high school station and discovering the lack of quality resources available for school-based broadcasters unable to obtain an FCC allocation. With many hobbyists also using this same technology on AM to serve their neighbors with micro radio it only seemed natural to expand the interest to hobbyists, too.

Also, Part 15 regulations allow for some use of the shortwave bands for experimental broadcasting with the most common frequency used by hobbyists being 13.56 MHz.

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Bermuda…Missing?

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"Uh, Charlie, where did Bermuda go?"

“Uh, Charlie, where did Bermuda go?”

My good buddy, David Goren, directed me to the VOLMET frequency for New York Sunday afternoon on 3,485 kHz.

VOMET, for those of you not familiar, is a worldwide network of radio stations that broadcast TAF, SIGMET and METAR aviation weather reports on shortwave radio, and in some countries on VHF, too. All of the reports are broadcast in upper sideband, using automated voice transmissions.

At any rate, they must have experienced a glitch which resulted in the loss of meteorological data for most of the United States. The broadcast preamble is as usual, but as soon as specific airport regions (mostly major US cities and some islands) are mentioned, the report takes a disturbing turn.  It’s fodder for science fiction–one is not sure whether to be alarmed or amused by this eyebrow-raising data (or, lack thereof).

The end result becomes almost like a numbers station, sans numbers, of course. Take a listen for yourself by clicking here to download the recording, or listen via the embedded player below:

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Even numbers stations make mistakes

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WFL_015On February 5th, 2013, the Cuban numbers station widely known as HM01 struggled to maintain its composure following an awkward studio error.

In this particular case, I started recording a few seconds prior to the carrier, at which point you’ll hear a couple of minutes of “dead air” (silence). The broadcast starts around 2:25, cutting into the middle of a data burst; the station then goes silent before it comes back on at 5:15 with numbers, then abruptly stops. At 6:15 the station restarts the numbers broadcast in earnest.

Download the MP3 of the full recording by clicking here, or listen via the embedded player below:

Click here to view the Archive.org with original audio files.

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Reader Chris shares travel recordings: Voice of Mongolia, Korea

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Map pointing to Truk Lagoon (Source: truk-lagoon.com)

Map pointing to Truk Lagoon (Source: truk-lagoon.com)

SWLing Post reader, Chris Johnson, recently sent me a message confessing his love of travel combined with shortwave radio listening. When he told me about his enviable plans to travel to the tiny islands of Truk Lagoon in the Federated States of Micronesia–and to record some of the broadcasts he heard–I asked if he would allow me to share his recordings on the Post. Fortunately for us, he agreed!

Below are two of his recordings, the first from the Voice of Mongolia, the second from the Voice of Korea. Both happen to be very difficult stations to catch here in eastern North America. His comments follow each recording:

Voice of Mongolia Shortwave Broadcast to Asia and Europe. Using a Sony ICF-SW7600G with a whip antenna. Recorded on 29 January 2013 at 1030z on 12085 khz from the Blue Lagoon Resort, Truk Lagoon, Federated States of Micronesia. The broadcast interval signal begins at 1:35

Voice of Korea; Recorded on a Sony ICF-SW7600G using a whip antenna. 7 February 2013 on 15100 khz at 0500z Location; Puka Beach, Boracay Island, Philippines. The program was scheduled for 60 minutes but due to the frequent power outages in the DPRK, the program ceased at approximately 52 minutes.

Thanks, Chris!

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Shortwave Radio Recordings: Saturday Night Country

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Emma Swift is filling is hosting Saturday Night Country while Felicity Urquhart is on maternity leave. (Photo: Radio Australia)

Emma Swift is hosting Saturday Night Country while Felicity Urquhart is on maternity leave. (Photo: Radio Australia)

As on many Saturday mornings, this past weekend I sipped my morning coffee while listening to ABC’s Saturday Night Country from Radio Australia’s Shepparton shortwave transmission site on 9.58 MHz…some 9,800 miles from my home.

In this program, Emma Swift continues to fill in for Felicity Urquhart (who is on maternity leave). Swift, who is an amazing host and songwriter in her own right, focuses in this show on country drinking songs (amongst others) and on a few nostalgic country songs in the final set. Fortunately, I captured the whole show in two recordings.

Click here to download the first recording and here to download the second as MP3s. Alternatively, you can simply listen via the embedded player below:

The Archive.org download page for these recordings can be found here.

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

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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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VOA protests jamming of English service to China

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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.

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