Wednesday, April 30, 2008

Alaskan DRM experiment proposed

Digital Aurora Radio Technologies of Delta Junction, Alaska has applied to the FCC for authorization to experiment with statewide DRM in the 5, 7 and 9 MHz shortwave bands. The FCC has assigned the callsign WE2XRH to this station, but its licence is pending. Delta Junction is approximately 130 miles southeast of Fairbanks.
“The ultimate goal of this project is to provide a terrestrial digital radio service to the citizens of Alaska,” the company said. “In general, the population of Alaska is underserved with respect to the ability to have a high quality, reliable public radio audio service. This is especially true for sparsely populated areas of the state.”
Digital Aurora would perform propagation, S/N, field strength, bit rate and audio quality measurements over a two-year period. The signals will be contained in a 10 kHz channel, but the test may include a wider signal to investigate the impact on broadcast quality and “expanded digital capabilities.” Transmissions will be coordinated with the High Frequency Coordination Conference.
“It is clear from the coverage contours that nearly all of the energy is concentrated for reception in Alaska,” the company said. Major parts of the planned experiment will be to investigate how well the propagation predictions reflect field conditions and how low the transmit power can go below 100 kW without jeopardizing coverage in some parts of Alaska.
A unique element of the proposed station is its use of government surplus over-the-horizon (OTH) radar transmitters. Tests by the OTH system manufacturer, Continental Electronics, demonstrated the capability of the transmitter to broadcast DRM with “excellent performance characteristics” and within the spectral mask recommended by the ITU for this mode.
“An Alaskan experiment will fill a gap in assessing the performance of digital terrestrial shortwave broadcasting in the difficult high latitude environment,” the company said.
(Source: Netherlands Media Network Weblog)