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Long-Range UHF Radars for Ground Control of Airborne Interceptors

■ The standard Air Force radars available in the early 1950s had major shortcomings for air-battle management in the face of plausible threats. At that time Lincoln Laboratory was achieving impressive success in developing UHF radars for airborne early warning with moving-target indication by changing from shorter to longer operating wavelengths. It appeared that similar innovations would also yield major performance improvements for radars devoted to the ground control of airborne interceptors. Lincoln Laboratory developed and fielded two different UHF radars that showed that this promise could be fulfilled. Both had quite large antennas rotating in azimuth. A narrowband radar operating near 425 MHz was built on Jug Handle Hill near West Bath, Maine; it became a primary sensor for the Cape Cod System and the Experimental SAGE Subsector. A broadband radar operating across the 400-to450-MHz band was built atop Boston Hill near North Andover, Massachusetts. This radar was designed as a test bed for the development of techniques to combat active electronic jamming and passive countermeasures such as chaff dispensed by hostile aircraft. These radars paved the way for subsequent Air Force efforts to achieve frequency diversity in its air-defense network.