Despite the FCC's glowing remarks about LightSquared, the conditional approval made it clear the plan would never gain final clearance unless it could be implemented without interfering with GPS devices. In a nutshell, LightSquared needed a special waiver because it is trying to use spectrum allocated for low-power space-to-ground transmissions for something it was not originally allocated for: high-power ground-only transmissions that could fuel a nationwide wireless mobile broadband network. The portion of L-Band spectrum controlled by LightSquared is adjacent to the spectrum used by GPS devices, and GPS devices, according to repeated tests, would be unable to receive the signals intended for them because the high-power LightSquared signals would overpower the GPS ones.
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In the end, though, it was not politics, but the results of repeated tests which the FCC could not ignore, and thus doomed LightSquared. The ruling against the company seems to be grounded in science and common sense, coming swiftly after the NTIA reported to the FCC that months of analysis determined that "LightSquared's proposed mobile broadband network will impact GPS services and that there is no practical way to mitigate the potential interference at this time. Furthermore, while GPS equipment developers may be able to mitigate these issues via new technology in the future, the time and money required for federal, commercial, and private sector users to replace technology in the field and the marketplace, on aircraft, and in integrated national security systems cannot support the scheduled deployment of terrestrial services proposed by LightSquared." The NTIA further noted potential problems for air traffic navigation and NASA's "future space-based GPS receivers" that would be sensitive even to LightSquared's usage of signals in the lower 10MHz.