Historic California Posts, Camps,Station and Airfields
Tierra del Sol Gap Filler Annex P-76C
(Hipass Gap Filler Annex P-76C)
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
US Army Corps of Engineers Los Angeles District History (1992)
The former Tierra Del Sol Gap Filler Annex (previously known as Hipass Gap Filler Annex, designated changed 30 June 1958) was located on a parcel of land approximately 54 miles southwest of El Centro, South of state Route 94 on Tierra Del Sol Road, San Diego County, California. The Tierra Del Sol Gap Filler Annex was acquired by the Untied states Air Force to be used as a radar gap filler annex. The land was acquired fee simple by direct purchase (No. LA-49) from Richard C. and May M. Singleton on 13 November 1956. The site consisted of 0.89 acres, of which
0.15 acre is in road.

The Tierra Del Sol Gap Filler Annex was use as an unmanned gap filler station and a masonry block gap filler building exists. According to the Report of Excess Real Property submitted by the U.S. Army Engineer District, Los Angeles, dated 24 January 1962, the following are the site improvements:
The date of construction is not known. There is no evidence that the area was under other than Air Force control during the period of Department of Defense (DoD) ownership.

The Air Force terminated the ownership of the site by transferring the parcel to the state of California on 3 June 1963, via quit claim deed. the new owner, California Division of Forestry (now California Department of Forestry and Fire Fighting or CAL FIRE), currently uses the main building as a fire station (named White star Fire Station). The land is presently used as a fire station. The building, concrete walks, access road and tower foundation are still present, based on a site visit on 7 December 1987.


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Updated 8 February 2016