Category Archives: Digital Modes

Saturday, from Bulgaria, Dr. Elliott will control your web browser

“Let Dr. Elliott take control of your PC!”

I agree.

On several occasions now, Dr. Kim Elliott has transmitted digital messages via shortwave radio in an assortment of digital modes. We’ve mentioned this in the past (and we even posted a tutorial on decoding his WBCQ message).

Early Sunday morning (UTC–Saturday night for many) The Mighty KBC will once again broadcast some of Elliott’s digital messages from 00:00-02:00 UTC on 9,450 kHz. This time, they’ll even broadcast two different messages in two different modes simultaneously (details below). No Johnny, this isn’t your granfather’s shortwave:

(Source: Kim Elliott)

The Mighty KBC, 21 Nov 2012: “This UTC Sunday, 25 November, more digital text during the broadcast of The Mighty KBC at 0000 to 0200 on 9450 kHz. At about 0130 UTC, PSK125 will be centered at 1300 Hz on the waterfall, MFSK32 at 2200 Hz. Decode one from the radio, and the other from your recording. Just before 0200, only one mode, MFSK32, will be transmitted, centered at 1500 Hz. For this message, please have Fldigi and Flmsg (both available from www.w1hkj.com), as well as your web browser, all running on your PC. If all goes well, at the end of this transmission, the message should pop up in new windows of Flmsg and your browser. (In Flmsg, click Configure, then Misc, then NBEMS, then check Open with flmsg and check Open in browser.)

[Elliott’s comments] “UTC Sunday 25 November at 0000 to 0200 UTC is the same as Saturday evening, 24 November, 7 to 9 pm Eastern Time in North America. This transmission on 9450 kHz is via a leased transmitter in Bulgaria.

To decode the two text transmissions, download Fldigi and Flmsg from w1hkj.com. Configure Fldigi to work with your PC’s sound card.

Also, in Fldigi, click Configure, Misc, NBEMS. Under NBEMS data file interface, click Enable. Under reception of flmsg file, click Open with flmsg and Open in browser.

During reception, patch audio from the earphone or line out jack of your radio to the microphone input of your PC. You may have to experiment a bit with audio settings. You should see a “waterfall” on your Fldigi display.

If all goes according to plan, when the text message just before 0200 UTC (9 pm Eastern) is completely received, it should pop up in a new window of your default web browser.

By the way, if you haven’t noticed, I’m a big fan of The Mighty KBC. Not only do they broadcast an excellent mix of music on shortwave radio, but they’ll also blast these digital messages to their listeners. Thanks, KBC!

Again, please comment if you decode these messages!

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The Mighty KBC tests 9,450 kHz and will send a digital message this weekend

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KBC Propagation Map (Source: The Mighty KBC)

This Sunday, from 00:00-02:00 UTC, The Mighty KBC will again broadcast 2 hours of music on the 31 meter band. This time, they will be testing on 9,450 kHz to avoid adjacent signal interference heard on 9,500 kHz last week.

They will also broadcast a special digital message at 01:30 and then again prior to the end of their broadcast. They have sent full details about the broadcast in a press release (below). Note that though the mode is different, the procedure of decoding the digital message is similar to the one WBCQ broadcast this year. We published a short primer on decoding the WBCQ message in May.

Here are the details on Sunday’s broadcast and how to decode the QPSK125 message:

(Source: The Might KBC)

The Mighty KBC will test to the USA on Sunday 11 November 2012 00.00 – 02.00 UTC on 9450 kHz!

Please join the Mighty KBC for a test of a digital text sent via a shortwave broadcast transmitter. This will take place during the next transmission to North America, Sunday 0000-0200 UTC, at approximately 0130 and just before the end of the broadcast at 0200.

All you need is a basic shortwave receiver (no SSB mode is necessary), and a basic personal computer. Using a patch cord, you will feed the audio out of the earphone jack (or line out) of your radio into the microphone jack of your PC. If you don’t have a patch cord, you can try placing the speaker of your radio close to the built-in microphone of a laptop PC.

You will also need software. There are several freeware or shareware programs used by the amateur radio community that decode digital text modes. One is FLDIGI, available from http://www.w1hkj.com .

After installing FLDIGI, pull down the Configure menu, then click Sound Card, and select the soundcard your PC is using.

You might also have to adjust your audio settings. In Windows 7, left click twice on the speaker icon in the lower right of PC display, then click Options, then click Properties, then click Recording, then click the input that works. Other operating systems will have different procedures. A good way to test your audio settings is to try to decode the radio amateurs using the PSK31 mode on 14070 kHz.

For the test digital text transmissions on Sunday, The Mighty KBC will be using the QPSK125 mode. On your software, your cursor should be centered on 1500 Hertz, where you will see the “waterfall” of the QPSK125 signal. You can decode the transmission while you receive it, or record the transmission and decode from the recording. The latter will give you more opportunities to perfect the technique.

The test to be transmitted will be a formatted html file. Copy it from <html> to (and including) </html>, and paste it to a text editor (such as Notepad in Windows). Save the file, using any file name, with the suffix .htm or .html. Then open the file in any web browser. If all goes well, this might be the first time you receive a shortwave radio broadcast in color!

In the future, an app will be developed to make this process simpler!

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Radio World looks at DRM

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(Source: Radio World)

By: Ernie Franke

Once touted as the “Savior of Shortwave,” Digital Radio Mondiale has not lived up to its hype. Proposed in 1988, with early field-testing in 2000, inaugural broadcasting in 2001 and its official rollout in 2003, DRM has had a lackluster career over the last decade.

With the allure of FM-quality audio and fade-free operation, it had appeared that DRM might revive the shortwave community. Unfortunately, it has been overcome by other events, some technical and some social. The main weakness has been alternate sources of information and entertainment, fueled by the very technology that gave DRM hope.

Additionally, in areas of the world without ubiquitous social media, DRM has yet to realize receivers at a moderate cost with adequate battery life. The very processing technology that allows improved operation using the more complex DRM waveform costs more and consumes more power than the standard AM receiver. A quick look at standalone DRM receivers over the past decade shows almost a dozen companies entering the market, only to retreat when the promise didn’t materialize.

[…]The rise of the Internet has influenced many broadcasters to cease their shortwave transmissions in favor of broadcasting over the World Wide Web. When BBC World Service discontinued service to Europe, North America, Australasia and the Caribbean, it generated many protests. The shifting of resources from shortwave to Internet and television by the Broadcasting Board of Governors, which oversees U.S. international broadcasting, further reduced broadcasting hours in the English language. […]Although most of the prominent broadcasters continue to scale back their analog shortwave transmissions or completely terminate them, shortwave is still common and active in developing regions, such as parts of Africa and South America.[…]

The article then goes into an in-depth look at both the reasons for and technology behind Digital Radio Mondiale–both on the broadcasting and receiving ends.

Read the full article at Radio World’s website.

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German Armed Forces Radio testing in DRM

DRM Consortium publishes the DRM Introduction & Implementation Guide

North Korea is testing digital shortwave broadcasting via DRM

How to decode WBCQ’s digital message

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Last night, WBCQ’s sent a digital message about ten minutes before the end of the Allan Weiner Worldwide show. If you missed the broadcast, no worries; we recorded the show, and you can download the audio (below) to try decoding the message for yourself.

The digital message can be decoded using a variety of free software packages. The package we used–and which we use for many other digital modes–is FLDIGI, which can be found at http://www.w1hkj.com/Fldigi.html.

Downloading and installing FLDIGI is straightforward. But although this is a simple program, there is a slight learning curve involved. Below, we explain how to use FLDIGI to decode the message.

1. Download the mp3 recording by clicking here (right-click, then save file).

2. Download and install FLDIGI.

Screenshot of digital mode being selected in FLDIGI. Click image to enlarge.

3. Launch FLDIGI and tell it that you wish to decode the digital format MFSK-64. Do this by selecting the menu items “Op Mode” –> “MFSK” –> “MFSK-64.”

4. Play the audio so FLDIGI can decode the message.

There are a few simple ways to play the audio:

If your computer has a built-in microphone, simply play the pre-recorded audio file from an mp3 player with a built-in (or amplified) speaker. Hold the speaker near the computer’s microphone. FLDIGI can decode the digital signal from the computer’s buit-in microphone if the mp3 player volume and microphone gain are adequate. FLDIGI is reasonably forgiving, but you should try this in a low-noise environment.
Better yet, if you have a way to feed the audio directly from your mp3 player into the line-in (or microphone input) on your computer–say, with a shielded audio patch-cord–this will insure a clean signal into FLDIGI. Note that you should lower the volume of your mp3 player to do this. In some cases, you can actually damage your sound card if you feed it audio at a high volume.
Another method would be to play the mp3 file on your computer and use a program such as Virtual Audio Cable to link the audio to FLDIGI.

FLDIGI capturing the digital message and decoding. Note the solid block of color in the waterfall display. Use your pointer to click in the middle of this block in order to tell FLDIGI where to decode. Click image to enlarge screen capture.

Note that in our recording we include several seconds of normal audio before and after the digital message. When you watch the “waterfall” display on FLDIGI, you will see a solid block of coloring indicating the digital message when it begins (see screenshot on right). When the hosts are talking, this block will not be visible.

5. When the digital message begins, use your pointer to click in the middle of the block of color that represents the digital message in the waterfall display of FLDIGI. This tells FLDIGI where to find the digital message in the audio.

6. Your decoded message will appear in the text area of FLDIGI (as in the screenshot).

Image of decoded message as an HTML page. Note that copy was excellent, save one small error in the text. These minor errors are fairly normal in a digital broadcast. Click to enlarge.

7. Copy the decoded text to your PC’s clipboard, and paste into Notepad (or Word, OpenOffice, etc) and save the file as HTML by giving it a “.htm” or “.html” file extension.

Now the message should appear.

See, that wasn’t so difficult! This digital message could be decoded without purchasing any special software or other accessories. Most of us have everything we need to decode the bulk of the digital messages on the shortwave bands–and there are many, many more out there.

Please leave a comment if you successfully decoded this message, or if you have any other tips for decoding it.

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