China has developed a new tactical air defense radar designated AS901. This is a 242 pound unit that can be mounted on numerous vehicles to detect attacking aircraft. The unit includes a transceiver, identification friend-or-foe system, and control units. It requires 600 watts at 24 volts for direct current, but can run on 220 volt alternating current. The AS901 is a solid-date L-band pulse-Doppler radar. It can track 10 targets (interrogating them with IFF) while scanning for more. The Chinese claim that the AS901 can function effectively in a high electronic counter-countermeasures arena. Maximum range to detect an aircraft is 25 kilometers at maximum altitudes of 3,500 meters. Aircraft flying very low (100m) can be detected at 15 kilometers and helicopters ducking behind trees can still be detected at 10km. The antenna rotates at a rate of 10 revolutions per minute. The AS901 includes datalinks which can pass targeting data to weapons platforms. China insists that the AS901 has a mean time to failure of 400 hours in operation and a mean time to repair of 30 minutes.Stephen V Cole