sentences:  In 1979, the 671st Radar Squadron was replaced by the 20th Air Defense Squadron, Operating Location Alpha Juliet (OL-AJ).By 1988, the last of the two AN/FPS-90 sets was removed.Today, an ARSR-4 radar is part of the Joint Surveillance System (JSS), designated by NORAD as Southeast Air Defense Sector (SEADS) Ground Equipment Facility "J-07".