October 12, 2011: The U.S. Army has purchased 56 AN/MPQ-64F1 air surveillance radars. These systems, weighing six tons, are carried in a trailer that is towed by a hummer (which also carries an electricity generator). A crew of two operates the radar, which can be set up in under twenty minutes. Max range, even for small targets like cruise missiles and UAVs, is about 75 kilometers. Older AN/MPQ 64s had a range of 40 kilometers, and these are being upgraded. Max altitude is 20 kilometers (63,000 feet). This is a 3-D, 360 degree radar that revolves once every two seconds. The army already has a hundred of these radars, and plans to use them for another two decades.