Building 821: Radar Test Building
Built in 1947-48 as the first radar test facility at Wright-Patterson Air Force Base, Building 821 has been used predominately for antenna and radar cross section studies throughout its existence.
In the early 1950s, Bill Bahret, regarded by some as the "father of radar camouflage," designed and built the Air Force's first anechoic chamber for analyzing radar echo. The chamber stood in the middle of the floor, and radar absorption cones covered most of the interior walls. Although Bahret and his engineers knew that an objects shape and material had something to do with what showed up on radar, they did not set out to do "stealth" research. In fact, in those early days of radar cross section experimentation, the goal was simply to learn how radar interacted with bodies.
By the mid-1950s, the team in Building 821 was beginning to understand the relationship between radar and objects, and the different variables involved; only then did they start to wonder if they could actively reduce a model's radar "signature." Beginning in the late 1950s, a great deal of the early signature control technology was developed by the Propagation Group (precursor to the Radar Test
Building 821 continued to function as the Radar Test Building until 1990. However, for several years before, concerns had been growing which led to the eventual demise of Building 821's role as a radar facility: first, the Wright Aeronautical Laboratories wished to consolidate their operations (Avionics now resides in Buildings 620 and 22, and Signature Technology in Building 254); second, the amount of maintenance needed to sustain the aging building for radar testing was escalating (Building 821 has a history of maintenance problems, including a perpetually leaky roof, poor heating, and faulty alarm systems); moreover, Building 821's location just outside the main confines of the base poses security problems, especially for a facility doing highly classified research. In 1991, Logistics Supply took over Building 821 to use for shipping, receiving, and storage.
See the original Building 821: Radar Test Building document here.