FCC and their relationship to "lightsourced"

[lloyds]

I am surprised no one here has mentioned this. This could potentially have a huge impact on all of us, as well as the rest of the world. Apparently in our Presidents' zeal to deliver on his promise of 4G to all citizens he coerced the FCC into granting bandwidth to this firm called "lightsourced". To "make it happen" FCC did away with the required six months for study and public input and automatically granted the bandwidth request in a two week time period. To make a long story short what it does is gives them permission to build over 40,000 land based antennas for communications. Doesn't sound like that bad of thing, BUT, the bandwidth is directly adjacent to GPS satellite bandwidth. And at 50,000 times the power you can pretty much imagine which technology loses. The military, GPS manufacturers and suppliers, and users groups are fighting this vigorously so it would be nice to believe that this just can't happen but we will see. This directive was in direct opposition to the international commission which oversees bandwidth allocation. Lots on the internet if you care to search it.

[matt_unique]

"Coerced the FCC"? Sounds serious

I did a search and did not find anything for "lightsourced". Do you have a link handy? I would be very surprised if any actions were taken that would affect GPS signals as they are so highly integrated.

[Bill Uffelman]

LightSquared

http://www.wfsb.com/technology/27448640/detail.html

Bill Uffelman
In Carson City NV through June

[lloyds]

My mistake it is "lightsquared". If you google it you will find near the top the threat to gps which will also lead you to some other links. I am surprised this thing has stayed so quiet.

[lloyds]

Thanks Bill for correcting that. There is quite a bit more to the story but it takes some digging to find it. The administration was in a big hurry to get this thing going and almost got away with it. Now due to pressure on them, the government has put together a committee of users which is now up to about 34 folks. They will meet once a month and issue a report on their progress. I think they have released the first one, which details the committee and its' functions. I think it is supposed to be finished in june or july. That is the FCC standard as I understand it but the government got in a hurry for this one and tried to shortcut it and got caught. I know it sounds impossible that something like this could actually happen but we came incredibly close this time. I have no idea who blew the whistle, maybe another competitor but we are lucky someone was watching.

[Larry H]

Panbo, a marine electronics blog, broke the news on Mar 14.

Link. http://www.panbo.com/archives/2011/03/the_lightsquared_problem_time_to_join_save_our_gps.html

Also, our own Brat, Tim, wrote about it on his blog.

Link. http://www.navagear.com/2011/03/15/house-subcommittee-told-fcc-action-poses-a-threat-to-gps/

[Aurelia]

There is much hype and fear about this and it is a real concern generally but a little ahead of itself.

"as part of the waiver granted allowing LightSquared to operate a hybrid network in the L-Band -- that LightSquared must work with the satellite industry to study the issue and provide a solution if there is a problem. The first report from the 34-member group arrived on March 1, the second is due April 15, and the final report is due June 15."

They seem to be tasked with solving any problems and I really have a hard time believing that all of our GPS gear is just going to be blurred out for this system. GPS is a bit more established in our countries daily personal and business affairs than that. I am ignoring the hype and waiting to be proved right.

[localboy]

[lloyds]

You should ask the pres for his take on that one.

[Da Nag]

Great topic...I'm looking forward to hearing more details on the issue as things go forward.

But the following crap - I'll ask only once. Take it elsewhere.

[thataway]

This has been in the view finder since at least mid Feb. It is difficult to see where it will go. Even if Lightsource goes ahead, it will not cause a problem for marine navigation--but airplanes, and inland it can be a possible issue. The question remains if filters on both the recievers and transmitters will be adequate. I don't see a threat to our boating issues curently--but it is something which we need to keep an eye on.

There was also a threat a couple of years ago--broad band via power lines--and that would have caused some serious RF spectrum interference--and was eventually put on the back burner.

[rogerbum]

This pdf of a report from Garmin is quite interesting. It describes some experiments done at Garmin's facility in which they simulated the signals that would be sent by Light Squared's proposed system and measured the effect on two GPS systems - the Garmin Nuvi 265w and the GNS 430W. The former is one of the most common systems used in cars while the latter is one of the most common systems used in aircraft. Garmin picked these units because they have high market share and are representative of other units in the field. In the interest of getting some testing done quickly, they didn't test other units.

The bottom line of their testing is that the car units will be jammed when within 0.6 miles of a Light Squared transmitter when they have open sky to the GPS satellites (best case scenario) and at about 1.8 miles when they are in "urban canyons" (e.g. amongst tall building that block some satellite signals). For the aviation GPS, which has line of sight to both the transmitters on the ground and the GSP satellites, the situation is worse with jamming occurring at a distance of 5.6 miles from the simulated Light Squared transmitter.

As someone with some experience in electronics in these frequencies (I did a lot of spectroscopy using similar types of test equipment), Garmin's testing setup seems reasonable and (as they plainly stated) was done to provide a simulation of the conditions and setup most favorable to Light Squared - e.g. not at the full power Light Squared would be permitted to use and not at the full edge of the spectrum that Light Squared could conceivably use. Given Garmin's testing and the large number of deployed GPS's, I can't see the Light Squared units actually get deployed as projected. My money says that the rug is pulled out on this prior to it becoming a problem.

[jstates]

This concern was announced a few weeks ago and the 4G company indicated that it was in their interest to be sure 4G and GPS were compatible, since 3G &/or 4 G is often used with GPS at the same time on the same device. They won't have much market share if their 4G damages GPS performance.

I used Sprint 4G all last week in Seattle w GPS some of the time - no problem. The measured download speed up to 8 MB sec was fantastic

Jim

[Captains Cat]

[matt_unique]