Kim Andrew Elliott | The SWLing Post

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.

Edward R. Murrow transmitting station site in Greenville, NC

I recently read the following comments by Kim Andrew Elliott regarding the Broadcasting Board of Governors’ strategic move away from shortwave radio. I think Kim is spot-on:

As a shortwave listener for nearly a half-century, I am saddened to see the reduction of shortwave broadcasting, especially by US international broadcasters. As an international broadcasting audience research analyst, however, I see much data showing a decline in the number of of people owning and and listening to shortwave radios. Even in rural areas, audiences are moving to FM radio, television, and mobile phones.

US international broadcasting should employ, if possible, the media preferred by its target audiences. If access to those media are denied in the target country, then the use of more robust but less popular media is necessary. Shortwave can be jammed, but it still offers the most physical resistance to interdiction of any medium available to international broadcasting. New digital modes allow text to be transmitted very efficiently via shortwave, requiring much less power than needed for voice. Shortwave could therefore be an alternative means of delivery when the internet is blocked. (On the subject of internet blocking, see previous posts re Iran and China.)

For future emergencies, when the internet, mobile networks, cable television, and other popular forms of communication will be disrupted, the United States should maintain an interagency global network of shortwave transmitters. These can be used by US international broadcasting to reach key target countries, by the State Department to reach Americans abroad and for public diplomacy tasks, and by the military for information operations and other purposes. The output of each agency would remain separate. Their functions would not be intermingled. The shortwave transmitter network would operate as a common carrier.

No doubt that shortwave radio listenership is on the decline. Still, as we point out so often, many around the world still rely on the medium. Indeed, should those of us who regularly use the internet ever experience a regional/national internet blackout or other potential communications disaster, shortwave radio would be a reliable communications medium of last resort.

Broadcasters (like RCI) should not dispose of their broadcasting infrastructure during cuts. Kim’s suggestion of an “inter-agency global network of shortwave transmitters” is a worthy option.