LightSquared has filed a Petition for Rulemaking asking the FCC to allocate the 1675-1680 MHz band for terrestrial mobile use. Along with the 1670-1675 MHz spectrum it already has. This spectrum would replace the 1545-1555 MHz spectrum segment terrestrial purposes, avoiding--LightSquared claims--the problems of interference to GPS receivers that have thwarted its efforts to roll out a nationwide wireless network.
In the Petition, LightSquared said it would “Permanently relinquish its authority to conduct terrestrial operations in the upper 10 MHz downlink band at 1545-1555 MHz...”
If the Petition is granted, LightSquared would use 1670-1680 MHz for its terrestrial network and forgo use of its spectrum at 1526-1536 MHz, pending outcome of a separate FCC rulemaking petition. It would continue to use its two 10 MHz uplink bands at 1627.5-1637.5 MHz and 1646.7-1656.7 MHz under their existing technical parameters and match them to its alternative downlink channel in the 1670-1680 MHz spectrum.
The 1675-1680 MHz spectrum is used for federal and non-federal meteorological aids and the Meteorological-Satellite Service. LightSquared proposes that any operations in the band would “proceed in cooperation with federal government uses under the existing primary allocations of this band segment for meteorological aids and the Meteorological-Satellite Service. Use of this spectrum would impact private users receiving polar orbiting satellite NOAA 19 and NOAA 16 HRPT images.
Perhaps more important, the GOES-13, GOES-14, and GOES-15 geostationary weather satellite use frequencies at 1685.7 MHz and 1691 MHz for GVAR and LRIT digital images. Private weather services and hobbyists that receive weather images from the satellites could be impacted by LightSquared’s terrestrial use of this spectrum.
As the weather satellites use only part of the band, LightSquared is requesting and because large, directional antennas are used to receive the satellites, perhaps one solution would be for LightSquared to avoid use of the GOES satellite frequencies and perhaps the NOAA polar satellite frequencies.
The FCC issued a Public Notice inviting comments on LightSquared's proposal. Comments/Petitions to Deny are due Dec. 17, 2012, oppositions are Jan. 4, 2013 and replies are due Jan. 11, 2013.
Doug Lung is one of America's foremost authorities on broadcast RF technology. He has been with NBC since 1985 and is currently vice president of broadcast technology for NBC/Telemundo stations.
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