WiMAX: No Satellite Interference says WARC
WiMax Antennas May Interfere with Satellites, says DSL Reports, a story repeated by Om Malik and Crunch Gear today, after Engadget ran a story saying as much. They point to a Satellite Users Interference Reduction Group study that found sharing Fixed Satellite Services (FSS) with WiMAX services on the C-band spectrum (pdf) posed a significant interference threat to satellite signals transmitted in the C-band frequency.
It’s hardly news. Six months ago, WARC-07 ruled that WiMAX and other services can’t share satellite “C” band frequencies. The World Administrative Radio Council last year looked into whether part of C-band satellite spectrum could be shared by services like WiMAX — but ruled against it.
A typical “C band” satellite uses 3.7–4.2 GHz for downlink, and 5.925–6.425 GHz for uplink, according to Wikipedia. It is adjacent to the 3.5 Mhz band favored by fixed WiMAX, world-wide.
The ITU World Radiocommunication Conference (WRC) 2007, was held 22 October-1 November in Geneva. To keep their frequencies “pristine”, the satellite industry showed that WiMAX could interfere with a satellite digital signal more than 7 miles away — if WiMAX shared the satellite “C band”.
So WRC preserved the C-band for exclusive use by satellite operators last year. Case closed.
“The WRC-07 outcome was everything that the industry could have desired,” says Robert Bell, executive director, World Teleport Association (pdf).
The FCC opened access to the 3650-3700 MHz band (3650 MHz) in the United States. The hybrid regulatory model provides for nationwide, non-exclusive licensing of terrestrial operations.
In [real] space news, SES AMERICOM’s AMC 14, a communications satellite to be used by Echostar for direct, local-to-local HDTV ended in failure early Saturday after the launch of the Russian Proton’ upper stage booster suffered a glitch, dumping the DISH Network satellite in a useless orbit. The satellite “can be controlled but is in an orbit of 28,000 kilometres instead of the planned 36,000 kilometres“.
The Lockheed Martin A2100-based AMC-14 also carries an active phased array that can be reshaped on orbit. Lockheed Martin’s A2100 platform is also utilized in the DOD’s Advanced Extremely High Frequency, Mobile User Objective System (right) and Transformational Satellite program (TSAT).
- March 17 - DirecTV 11 on Sea Launch: A Zenit 3SL rocket is scheduled to carry the direct-to-home satellite (154° West) to increase local and national HDTV channels for DirecTV. Sea Launch will provide live coverage beginning at 3:30 pm PDT (22:30 GMT) on March 17.
- April 14 - ICO G1 on Atlas 5 : Craig McCaw’s big gamble for satellite phones. Space Systems/Loral is building the huge geostationary spotbeam spacecraft. Will use terrestrial repeaters and was built by Space Systems/Loral, based on the Loral 1300 platform.
- April: Inmarsat-4 F3 on Proton: Inmarsat’s final spotbeam (positioned over the Pacific) should deliver broadband at 492kbps (send and receive) to airplanes, ships and individuals using laptop-size antennas. Astrium will deliver both the platform (a high-power Eurostar-3000GM) and the payload, including the on-board processor. UPDATE: Inmarsat announced today that it won’t ship the third Inmarsat-4 F3 satellite to the launch pad until April, amid hand-wringing over the AMC-14/Proton “anomaly”.
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