Category Archives: Digital Modes

North Korean numbers station detected; possible submarine instructions?

The website Intellihub.com features an Op Ed piece regarding a recently detected numbers station supposedly originating from North Korea. The station, reported by a ham radio operator, is in single-side band and adjacent to the Voice of Korea.

Below is an excerpt from this Op Ed piece; note my comments following:
NorthKoreaMap

(Source: Intellihub.com)

Within hours of South Korean news sources breaking a story that several Sang-Ho class submarines had disappeared from their North Korean bases, a ham radio operator named Tim, picked up a “numbers station” broadcasting on the same frequency as “The Voice of Korea” propaganda station. [check out our recent post]  What makes this even more interesting is that at the tail end of the numbers transmission there was a long duration digital transmission as well.

So what makes this number station significant is the proximity in timing to the disappearance of the San-Ho class submarines, as well as the digital transmission.

[…]What is more significant is the digital signal at the end of the transmission.  Digital transmissions such as this one may indicate the presence of a burst transmission which contains a compressed and encrypted message bound for some covert force, somewhere.  Typically a burst transmission is used to minimize the download time at the end point to prevent discovery.  The unusual part of this potential burst transmission is being attached to a numbers station as well as the length and the power of the broadcast.  Normal burst transmissions are in the one second to two second range.  This transmission was in the 10 to 15 second range which is almost unheard of, unless the end point is a submarine.

[…]The ham operator who picked up this particular transmission was located in the Midwest of the United States, and he reported the transmission was received 4 by 5 indicating a significant power was used to send the transmission.  That level of power coupled with the length and possible submarine end point opens up a new and alarming tangent to this escalating conflict. It is important to point out that the numbers are being read in Spanish but that is typically done to confuse the original source of the transmission.  In this case the transmission was detected on a upper side band of the AM range used by the Voice of Korea so while the numbers are Spanish the transmission does appear to originate in North Korea.  That fact coupled with the missing submarines seems to provide evidence of the nature of the transmission despite being in Spanish.  Its also important to note that the numbers being in Spanish could also be used to employ a different set of codes in the operatives code books.

Short digital bursts, as they describe, are not necessarily that uncommon since the Cuban numbers station,HM01, has been doing this for years.  (Indeed, perhaps North Korea got a little help from Havana?) You can hear audio from HM01 here and here and learn how to decode RDFT (HM01’s digital mode) here.

Read the full opinion article on Intellihub.com.

Thanks to Dan for the tip!

VOA, Mighty KBC and PCJ: Radiograms this weekend

The Mighty KBC, the VOA and PCJ radio will broadcast radiograms (digital text) over shortwave radio this weekend.

Reception conditions could be challenging depending on the impact of the incoming CME (Coronal Mass Ejection) which is expected to disrupt the high frequency bands today. All the more reason to attempt to decode these messages as Dr. Kim Elliott is studying each digital mode and its ability to effectively overcome adverse conditions. Email your reports and audio files to: [email protected]

Here are details from each broadcaster:

KBCradioThe Mighty KBC

Broadcasting 14 April 2013 from 00:00-02:00 UTC on 7,375 kHz.

At about 0133 UTC, two slow (less than 60 WPM) but robust modes will be transmitted: Olivia 8-1000 centered on 1000 Hertz, and MFSK16 on 2000 Hertz.

At just before 0200 UTC, Olivia 8-2000, with Flmsg format, will be centered on 1500 Hertz.

VOARadioGramThe Voice of America

VOA Radiogram for the weekend of 13/14 April 2013 will feature the Olivia modes, with MFSK modes also transmitted for comparison.

The modes will be transmitted in groups of three, and all will be centered on an audio frequency of 1500 Hertz, except where indicated:

Olivia 8-1000, 58 WPM, 1:32 (program menu)
MFSK 16,  58 WPM, 1:52
Olivia 8-1000, 58 WPM, 1:44

Olivia 32-2000, 50 WPM, 2:09
MFSK 22, 80 WPM, 1:50
Olivia 16-2000, 80 WPM, 1:51

MFSK 32, 120WPM, 2:04
Olivia 8-2000, 120WPM, 2:04
Olivia 4-2000, 160WPM, 1:40

Olivia 16-1000 (centered on 2000 Hz) versus music, 2:03

MFSK 32 closing text and image,  :51

Reception reports with (if possible) sample audio and screenshots would be appreciated. Audio files from outside the United States are especially helpful.

[email protected]

Twitter: @VOARadiogram

Here is the VOA Radiogram broadcast schedule:
(all days and times UTC)
Sat 1600-1630 17860 kHz
Sun 0230-0300 5745 kHz
Sun 1300-1330 6095 kHz
Sun 1930-2000 15670 kHz
All via the Edward R. Murrow transmitting station in North Carolina.

pcjPCJ Radio

PCJ Radio will transmit text on 14 April 2013 at 02:27 UTC via WRMI, Radio Miami International on 9,955 kHz. The mode will be Olivia 8-1000.

VOA Radiogram this weekend

VOARadioGramHere are the details for the VOA Radiogram this weekend:

(Source: Kim Elliott)

VOA Radiogram on 30 and 31 March 2013 will feature the MFSK (multiple frequency shift keying) modes. This “menu” for the program shows the mode, center audio frequency, and duration of transmission in minutes:seconds…

MFSK4 1500Hz 0:40*
MFSK16 1500Hz 1:00
MFSK32 1000Hz 1:00
MFSK32 2500Hz 1:00
PSKR125 2500Hz 1:00
PSKR250 2500Hz 1:00
MFSK64 2500Hz 1:00
MFSK64 2500Hz 3:07 Flmsg format
PSKR500 2000Hz 0:58
MFSK128 2000Hz 0:57**
MFSK32 2000Hz 1:40 Image
MFSK32 1500Hz 0:58 Image

* No RSID. You must tune the audio frequency very carefully. (Don’t worry if it does not work!)

**The RSID might not work, so manually select MFSK128 (needs new version of Fldigi) and the 2000 Hz center audio frequency.

Transmission schedule:

(all days and times UTC):

  • Sat 1600-1630 17860 kHz
  • Sun 0230-0300 5745 kHz
  • Sun 1300-1330 6095 kHz
  • Sun 1930-2000 15670 kHz

All via the Edward R. Murrow transmitting station in North Carolina.

Please send reports, audio samples, screenshots, etc to [email protected].

If you are unable to listen to the program because of Easter weekend, this MFSK show will be repeated later this year.

PCJ Radio International radiogram, March 31st

pcj

(Source: PCJ Media)

On March 31st, 2013 PCJ Radio International will conduct a digital text through analogue shortwave broadcast of a radiogram.

Setting: MFSK32

Date: March 31, 2013

Time: 0227UTC

Frequency: 9955khz

This test will have a message in English and Spanish for listeners in Cuba and Latin America. Those in the South Eastern part of the United States will also be able to tune in and record the 2 to 3 min transmission. If all goes as planed the Cuban jamming against 9955 kHz won’t have any effect on the message we will transmit.

For information on the software needed to decode this radiogram visit the following URL:

http://www.pcjmedia.com/component/content/article/1-latest-news/224-pcj-radio-radiogram-test-march-27-2013

DRM tests from Moscow starting tomorrow morning

drmlogoThe WRTH Facebook page has noted that DRM tests from Moscow will take place on 25,900 kHz starting Friday, March 22nd (tomorrow) at 10:00 UTC and ending on Saturday, March 23rd at 10:00 UTC.

Details of each broadcast can be found here–see English version via Google Translate.

They’re asking that all DRM reception reports be logged in this online forum with a detailed description and even sound clips of audio reception, if possible.

VOA Radiogram: March 23/24 broadcast

VOARadioGram(Source: VOA Radiogram)

VOA Radiogram for March 23/24 will be similar to the past weekend’s program in that it features the PSK modes. Much of Kim’s script will be the same. In this weekend’s broadcast, however, only one mode at a time will be transmitted. This should improve the signal-to-noise ratio and ability to decode each mode.

Each will be centered on 1500 Hz:

  1. BPSK31 (1:00)
  2. PSK63F (1:00)
  3. BPSK63 (1:00)
  4. PSKR125 (1:00)
  5. PSKR250 (1:00)
  6. PSKR500 (1:00)
  7. PSKR1000 (1:00)
  8. PSKR125 (3:45) Plain text
  9. PSKR250 (2:40) Flmsg* formatted (with html)
  10. MFSK32 (0:55) Image

*Install Flmsg. Then, in Fldigi: Configure > Misc >  NBEMS > under Reception of flmsg files click Open with flmsg and Open in browser, and below that state where your Flmsg file is located.

If decoding performance is still not satisfactory, VOA Radiogram in future weekends will feature more robust modes, such as MFSK, MT63, and Olivia.

See VOA Radiogram: how to decode the modes.

VOA Radiogram transmission schedule
(all days and times UTC)
Sat 1600-1630 17860 kHz
Sun 0230-0300 5745 kHz
Sun 1300-1330 6095 kHz
Sun 1930-2000 15670 kHz
All via the Edward R. Murrow transmitting station in North Carolina.

Please send reception reports, audio samples, screenshots, etc.,  to [email protected]

Shortwave Radio Recordings: The Disco Palace (in DRM)

DiscoBallPerhaps one of the things I love the most about SWLing is the sheer variety of broadcasters out there. We can sample diverse offerings across a broad spectrum–from the BBC World Service to Radio Romania International, from pirate stations to numbers stations.

There’s even The Disco Palace: a station that plays only disco music, and each show is mixed thematically. This station broadcasts online and over shortwave radio via DRM (Digital Radio Mondiale).

Last week–specifically, on March 15, 2013–I caught about thirty minutes of The Disco Palace broadcast and was able to record it from my Bonito RadioJet IF Receiver. Reception on 17,875 MHz was excellent, although the DRM signal wasn’t quite strong enough for comfortable stereo decoding.

The following TDP recording starts around 2030 UTC (about halfway through the broadcast). Click here to download the recording as an MP3, or simply listen via the embedded player below: