To prevent disruption to the cellular phone network from the effects of fast-moving cell phones at altitude (see Technical discussion, below), the FCC has banned the use of mobile phones on all aircraft in flight. The FCC did, however, allocate spectrum in the 450 MHz and 800 MHz frequency bands for use by equipment designed and tested as "safe for air-to-ground service" and these systems use far more widely separated ground stations than standard cellular systems. In the 450 MHz band co-channel assignments are at least 497 miles apart and in the 800 MHz band only specific sites were authorized by the FCC. The 450 MHz service is limited to "general aviation" users, usually corporate jets, while the 800 MHz spectrum can be used by airliners as well as for general aviation. The 450 MHz spectrum is named AGRAS while the name of the 800 MHz service is under review following an auction of the spectrum in 2006.