Ther's a great picture of the site at the More Info URL.
Clear Air Station is a Ballistic Missile Early Warning System (BMEWS) radar site which is one of three in the world. Built in 1959 it was used to detect enemy missile attack. It is now used to track satellites and space debris and covers 120 degrees in azimuth and approximately 3,000 nautical miles in range. It is located 40 miles north of Mount McKinley and 80 miles south of Fairbanks. Air Force personnel stationed there receive overseas pay and their families are not permitted on the base due to its top secret security status.
In 1995 the Clear Radar Upgrade program, a $106.5 million project, replaced the last mechanical radar in the Ballistic Missile Early Warning System network, operated by the 13th Space Warning Squadron. The existing mechanical radar was replaced with a phased array warning system, commonly referred to as PAVE PAWS. PAVE is an Air Force program name, while PAWS stands for Phased Array Warning System.