Historic California Posts, Camps,Station and Airfields
Joshua Tree Gap Filler Annex P-76F
Typical AN/FPS-14 Gap Filler Radar
"During the late 1950s another area of progress was the development and deployment of AN/FPS-14 and AN/FPS-18 gap-filler radars. Having a range of around sixty-five miles, these radars were placed in areas where it was thought enemy aircraft could fly low to avoid detection by the longer-range radars of the permanent and mobile radar networks. Gap-filler radar deployment peaked in December 1960 at 131 sites throughout the continental United States. Because the introduction of gap-filler radars alleviated the need for civilians to scan the skies for enemy bombers, the ADC disestablished the Ground Observer Corps on January 31, 1959."
Searching The Skies
USAF Air Combat Command
June, 1997
Typical floorplan of a Gap Filler Annex
On March 24, 1958, 13.10 acres were acquired by the US Air Force from the Department of the Interior as a military right of-way and installation pursuant to Department of the Interior Regulation 44-LD-513. Of this 13.10 acres, the gap filler site consists of 0.26 acres. An access road comprises the remaining 12.84 acres. An additional 1.49 acres of privately owned land required for the access road was acquired by way of permanent easement on July 21, 1958, bringing the total to 14.59 acres.

The site has been used for a gap filler/radar facility by the Air Force and subsequently the Navy since 1958. Site improvements consist of an approximately 1,200 square foot masonry block building with an antenna, three cement pads which appear to have been foundations for a large tower, a 2000 gallon fuel storage tank, and a chain link fence surrounding the facility. The site's radar covered those areas that geography blocked the radar at Boron Air Force Station.

Rights to the facility, access road and easement were transferred to the US Navy on June 4, 1965, as indicated on DD Form 1354 of the same date.
Source: Los District, US Army Corps of Engineers
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Updated 8 February 2016