Category Archives: Digital Modes

VOA Radiogram features EasyPal digital images this weekend

VOARadiogram(Source: VOA Radiogram)

During the past weekend, EasyPal digital images were received successfully throughout Europe and North America. You can see a gallery of some of the received images here:

voaradiogram.net/post/51385444401/voa-radiogram-easypal-images-received-100-or-0

Reviewing the advantages of EasyPal versus MFSK32:

EasyPal:

1) When received successfully, the picture is perfect.

2) Takes less time to transmit than MFSK32 and most SSTV images of the same size.

3) No problems with slant if soundcards are not calibrated.

MFSK32:

1) If the signal drops below a certain level, or if interference exceeds a certain level, no EasyPal image will be received at all. Under similar reception conditions, MFSK32, which uses an analog frequency shift keying system for images, will allow the an image to be seen, even if the quality is not perfect.

2) MFSK32 images allows images of different heights and widths, including small images which can be transmitted quickly. The gray tone MFSK32 image option allows even faster transmission.

3) MFSK32 images can be decoded by more than one software program under more than one operating system. There is only one EasyPal program, and it works only under the Windows operating system.

I welcome your comments and suggestions about the transmission of images via shortwave broadcast. Weighing all of the above factors, I am inclined to adopt MFSK32 as the primary image mode for VOA Radiogram. However, the EasyPal images are so impressive that I will continue to include some in future programs.

On VOA Radiogram for the weekend of 1 and 2 June 2013, we will continue to compare MFSK32 and EasyPal images. Here is the lineup for the program:

3:44    MFSK16: Program preview
3:17    MFSK32: VOA News story about Olympics wrestling
3:16    MFSK32: VOA News story about 2013 hurricane season
1:10    MFSK32: File image of Atlantic hurricane
2:53    MFSK32: VOA News story about colliding galaxies
1:04    MFSK32: Image of the colliding galaxies
1:21    MFSK32: Introduction to MFSK64 and EasyPal
1:30    MFSK64: Same VOA News story about colliding galaxies
:39     EasyPal text: Same VOA News story about galaxies
2:38    EasyPal image: Colliding galaxies
2:38    EasyPal image: Soyuz capsule being moved to launch site
1:09    MFSK16 closing announcements
:29     Surprise mode of the week

To decode EasyPal text and images, download the 4-May-2013 version of the program from vk4aes.com.

To decode the MFSK modes, use Fldigi from w1hkj.com or another digital decoding program.

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 to [email protected]

And visit voaradiogram.net (where any schedule or frequency changes will be posted)

Twitter: @VOARadiogram

Kim

Kim Andrew Elliott
Producer and Presenter
VOA Radiogram

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Capture images on the VOA Radiogram this weekend

VOARadioGram(Source: VOA Radiogram)

VOA Radiogram for the weekend of May 11 and 12 will feature long stretches of VOA News in plain text, using the MFSK 32 and 64 modes. No Flmsg or Flamp this time. This weekend’s program will also include our first test of slow scan television (SSTV).

Here is the lineup:

MFSK16 (2:28)     Preview

MFSK32 (12:08)     VOA News stories

The first of the three stories will be in Spanish. This is to determine how letters with accent marks appear on your display. The second VOA news story will be followed by an accompanying MFSK32 image

MFSK16     Intro to the next mode

MFSK64 (3:34)    VOA News story

MFSK16     Intro to the next mode

SSTV Scottie DX (4:31)

There are several software programs that decode SSTV, including Digital Master 780 (DM780) andMMSSTV. A free receive-only SSTV decoder is RX-SSTV from users.belgacom.net/hamradio/rxsstv.htm

MFSK16 (1:11)     Closing announcements

Closing music, accompanied by the surprise mode of the week

Please send reception reports to [email protected]

Screenshots and audio samples are welcome, especially audio of less than perfect reception conditions.

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.

 

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Shortwave Radio Recordings: The Mighty KBC

The Art of Noise kicks off this Mighty KBC broadcast. (Photo: Wikimedia Commons)

The Art of Noise kicks off this Mighty KBC broadcast. (Photo: Wikimedia Commons)

The Mighty KBC broadcast again early this morning (from 00:00-02:00 UTC) on their new summer frequency of 9,925 kHz. Their signal from Nauen, Germany was packing 125 kW–it was amazingly strong into North America. As we’ve come to expect, the KBC’s Giant Jukebox of music has a lot of rock-n-roll and Euro-pop variety, spanning the decades; DJ, “Uncle Eric” knows how to entertain and spin the tunes!

You can listen to the full recording below in the embedded player, or simply right click this link and save the MP3 file to your computer:

You’ll notice that Kim Elliott has another installation of digital text modes in this broadcast. Decode these digital modes using Fldigi from www.w1hkj.com. Be sure to check out Dr. Elliott’s VOA Radiogram website for full details about this broadcast.

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VOA Radiogram for April 27/28 includes Thor50x2, PSK63F, and Flamp

VOARadiogram(Source: VOA Radiogram)

Apologies for not updating this website since the April 20/21 VOA Radiogram. I have been diverted by deadlines connected to my other full-time job, audience research analyst for the International Broadcasting Bureau.

Thanks to all who sent reception reports, screenshots, audio samples, and other materials from the past weekend’s program. MFSK held off a challenge from the Thor modes and remains the most successful of the modes we have tested.

However, because your producer omitted the Thor 50×2 mode — a mode that might prove to be robust — from that program, VOA Radiogram on April 27/28 will include a “make good” transmission of Thor 50×2. And a transmission of Thor 50×1 for comparison.

There will also be a transmission of the PSK63F mode. This rather slow mode performed well during VOA Radiogram 1, but we only gave it a minute. There will be a longer transmission of PSK63F this weekend to allow a better evaluation.

The last text transmission this weekend will be in the Flamp format. If you don’t already have it, please download Flamp from www.w1hkj.com. Flamp divides a text file into several blocks, each with a specific number of characters. If any block is received without the correct number of characters, that block is rejected. The missing block can be picked up during the repeat transmission. Flamp might be useful for those text transmissions that are received at about 90% copy, when occasional deep fades prevent 100% copy. In Flamp, under Configure, check both of the Auto sync boxes.

Here is the lineup for the April 27/28 VOA Radiogram:

MFSK16 (58 wpm) program preview
PSK63F (55 wpm), 2:50
MFSK32 text (120 wpm) and image, 4:28
Thor50x1 (180wpm), 1:48
Thor50x2 (180wpm), 1:46
MFSK64 (240 wpm), 2:16
MFSK128* in Flamp X2 format, 3:46
MFSK32 image

*Probably a good idea to set the MFSK128 mode manually rather than depend on the RSID

All modes will be centered on 1500 Hz.

Each mode will be introduced by a brief MFSK16 transmission, same as last weekend.

Please send reception reports to [email protected]

Twitter: @VOARadiogram

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.

Kim

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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!

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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.

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