Delta Junction, AK (August 27, 2008)–The Digital Radio Mondiale Consortium (DRM) recently announced that the Federal Communications Commission (FCC) has granted a license to Digital Aurora Radio Technologies (DART) to conduct a two-year experiment for coverage of the state of Alaska with DRM signals in three of the lower shortwave bands.
If the tests show excellent results for digital broadcasts to cover the entire state, the next step would be to obtain approval to use the DRM system and the transmission station for a regular broadcasting service.
Alaska has a surface area of approximately 1,300,000 square kilometres. With one DRM transmission, either 10 or 20 kHz in bandwidth, the entire state would be covered with approximately “FM-like” quality for up to four simultaneous programs.
Because of the severe ionospheric propagation conditions at the high latitudes for the state, these experiments will yield valuable information on what is needed to get excellent audio coverage at realistic powers for this concept–that is, for “regional coverage” on the order of hundreds of thousands to perhaps two million square kilometers from one shortwave transmitter located “in the middle” of the coverage area.
The full test plan will include several variations of DRM system variables in order to determine which combination works best under the different ionospheric propagation conditions to be encountered. For the latter, this includes sunspot number, season and time of day. For the former, it involves different levels of audio quality for example with or without stereo and different levels of error correction. Finally, there is the choice of the three shortwave broadcasting bands at around 5, 7 and 9 MHz. Shortwave radio operates in the 3-30 MHz band.
Unlike the FCC-approved, iBiquity-controlled HD Radio format, DRM is an open, non-proprietary, digital standard that requires no licensing or running fees be paid to the organization and is employed by such shortwave broadcasters as the BBC World Service, Radio France Internationale and Voice of America.
Digital Radio Mondiale