The Avco AN/FPS-26 Radar was an Air Defense Command height finder radar developed in the Frequency Diversity Program with a tunable 3-cavity power klystron for electronic counter-countermeasures (e.g. to counter jamming). Accepted by the Rome Air Development Center on 20 January 1960 for use at SAGE radar stations, the AN/FPS-26 processed height-finder requests (e.g., from Air Defense Direction Centers) by positioning to the azimuth of a target aircraft using a high-pressure hydraulic drive, then "nodding" in either a default automatic mode or by operator command. The inflatable radome required a minimum pressure to prevent contact with the antenna which would result in damage to both (technicians accessed the antenna deck via an air lock.) To maintain high dielectric strength, the waveguide was pressurized with sulfur hexafluoride (SF6), which technicians were warned would produce deadly fluorine if waveguide arcing occurred.

Opheim Air Force Station is a closed United States Air Force General Surveillance Radar station. It is located 3.3 miles (5.3 km) west of Opheim, Montana. It was closed in 1979.