LightSquared GPS Protection Garners Public Comment

Documents have started appearing in the FCC Electronic Comment Filing System (ECFS) in response to the FCC's invitation for comments on LightSquared's request for declaratory ruling concerning resolution of GPS interference concerns about its terrestrial use mobile satellite services (MSS) spectrum near GPS bands.

(Comments can be found on the FCC's ECFS Full Text Search by entering "10-142" in the "Proceeding" box.)

A typical filing comes from Anthony Rumpca who states, "I belong to a search & rescue unit that uses GPS's to help in finding missing people. GPS's have aided in many searches and while I cannot say that without them it would have resulted in loss of life, I can say that GPS's have reduced the amount of time it would have normally taken to locate the missing person. Please don't allow LightSquared to degrade the efficiency of the tools we need to help aid the public."

Michael Mable, in his more detailed comments addressed LightSquared's contention that manufacturers of GPS devices susceptible to interference from LightSquared's proposed terrestrial transmitters are at fault because they did not provide sufficient filtering:

"This is not due to 'poor design' of existing receivers, it is due to those receivers being designed for the present operating environment, where the L-band is kept 'quiet' and reserved for low-level satellite to earth transmissions," said Mable. "It is possible that receivers could be built today with better rejection of high-level out-of-band signals, and maybe that is something for the future, but for the present, installed user base of receivers are not so designed. Some of these receivers could, possibly be retro-fitted with filters (at whose expense?) but the majority of receivers could not be. So far as I know, there has been no truly independent testing to demonstrate the efficacy of any of the filter solutions proposed."

The deadline for filing comments is Feb. 27, 2012. I do not expect to see filings from companies and nationwide interested organization to appear in ECFS until closer to the deadline. Reply comments are due March 13, 2012.

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.