The Digital Radio Mondiale standard for digital broadcasting in long, medium, and shortwave bands offers the possibility to transmit audio, text and pictures.
A few broadcasters use DRM for both domestic and international transmissions. DRM’s largest problem is lack of receivers, especially affordable standalone ones.
Some listeners use an SDR, computer and free Dream software to receive the DRM signals, but this audience doesn’t make up the mass audience that broadcasters are looking for.
A FEW ISSUES
In addition, the Dream has two serious limitations: It can’t receive the latest DRM codec (xHE-AAC) and its current version is unable to receive MOT Slideshow.
Many international broadcasters will not commit to DRM transmissions because of the lack of receivers. There is an effort by some broadcasters to coordinate the purchase of thousands of standalone DRM receivers in the hope that this will jump-start the market for receivers. This effort is rather capital-intensive, however.
There are millions of Android and Apple smartphones and tablets already in use. What if they included an app that could receive DRM? What if that app could be coupled to the SDRs already in the hands of listeners?
HOW IT WORKS
AlgorKorea didn’t develop the apps with the intention of solving the DRM receiver issue. They developed them to resolve a problem with FM hearing aids used in classrooms.
So how do they work? The DRM+SDR version couples the popular and inexpensive RTL-SDR to an Android device with a USB OTG adapter.
The DRM+ app is compatible with both Android and Apple devices and couples to the SDR using audio cords. A common and inexpensive resistor/capacitor needs to be soldered into one of the cords.
The app can receive MOT Slideshow, DRM texts and Journaline, a text news/information feed. AlgorKorea says it’ll continue to develop DRM apps. “We’re working on another new app (an inexpensive SDR dongle) for the Msi SDR Panadapter,” added Dr. Jarng.
Apps will play an important role in solving the DRM receiver problem and Algor’s offerings appear to be just the beginning.
Hans Johnson has worked in the shortwave broadcasting industry for over 20 years in consulting, frequency management, and sales.