I found this on another of our sites and just brought it over here . Sorry if posted already . A NOTAM is warning operators of “all aircraft relying on GPS” of widespread GPS outages starting Tuesday throughout the Southwest and especially southern California. Although the FAA doesn’t go into detail, it seems the military is testing something that can disrupt GPS over a huge area, centered on China Lake, California, home of the Navy’s China Lake Naval Weapons Center. On Tuesday, June 7, the FAA is warning that GPS signals down to 50 feet AGL could be “unreliable or unavailable” between 9:30 a.m. and 3:30 p.m. local time over a radius of 253 nautical miles, which includes the L.A. Basin, Bay area and Las Vegas. There will be further outages of similar potential duration June 9, 21,23, 28 and 30. The circles expand with altitude and at 40,000 feet the interference will affect a circular area of the Southwest 950 nautical miles across, reaching central Oregon, Colorado and New Mexico.