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“.
- 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”.
