Could 4G jam your GPS?
"The GPS industry is warning that a proposed broadband Internet network could effectively jam GPS signals. " A company called LightSquared has gotten FCC authorization to effectively reallocate L-band spectrum for terrestrial use. L-band has been used to transmit the weak GPS signals used by farmers, the military, aviation, emergency services and virtually all of society. The new transmitters that LightSquared plans to use, primarily in urban areas, can cause a Garmin 430W to lose signals at 4 miles. The Garmin 430W is a sample of the devices used by airplanes to land in low visibility. Garmin also tested one of their car GPSs and found it lost signal. Not many of us farm in an urban environment, but if you do it is conceivable that you could lose GPS tracking.
This is likely to be an interesting and probably public discussion.
From what I understand, GPS was using a frequency spectrum reserved for space and set up it's equipment accordingly. LightSwared apparently got the FCC to allow ground based use as well. That means that GPS is now responsible for filtering out adjacent signals, which GPS says are so stgrong they can't. So, what seems to be happening is LightSquared got the rules changed and are now trying to use their new rules to bully everyone who was already there. GPS is worried that they did nothing wrong but with new rules they may not be able to make their equipment work or it may require expensive redesign. If that is the case, you can kiss your present GPS good bye whenever you drive into the middle of Denver, Chicago, LA, etc.
We'll have to see how this all falls out. To learn more, Google using terms like "gps, l-band, lightsquared" etc. There is getting to be a very lively discussion.