Wildcat Ridge WWII Radar Site

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Wildcat Ridge WWII Radar Site (1942-1946) - A World War II U.S. Army Radar Site established in 1942. Used to provide fire control information to large caliber (6" and above) coastal gun batteries in the Harbor Defense of the San Francisco against enemy warships. Located on Wildcat Military Reservation near Olema, Marin County, California. Closed in 1946.

Wildcat Ridge WWII Radar Site Map.
Wildcat Ridge WWII Radar Site Transmitter Building Plan.

History

Part of the Harbor Defense of San Francisco.

SCR-296A Typical Radar Set Installation.

Constructed under project No. RAD-9-177 and transferred for use on 8 Jun 1944 as Wildcat Ridge WWII Radar Site. Construction costs to date of transfer were $13,248.17. The physical plant consisted of a transmitter building, two powerhouses each with a 1000 gallon fuel tank, a 25' steel tower and an antenna housing disguised as a Water tank atop the tower. The buildings and the tower were placed on concrete pads and footings installed by the Corps of Engineers who erected all of the structures. The engineering construction work was done by government forces.

The radar equipment was installed by the Signal Corps. It required 16.3kW of 120/240 AC, 1 phase, 60 cycle power furnished by the two on-site 25kw generators. The 25 kW generators were furnished and installed by the Signal Corps.


Site Operation

SCR-296-A Range Operator Display.
SCR-296-A Azimuth Operator Displays

In operation, the SCR-296-A radar could only track one target at a time. Target assignments were made from the harbor HECP/HDCP command posts by telephone, citing the approximate range and azimuth of the target using the SCR-582/SCR-682 search radar and/or optical spotters. The SCR-296-A radar operators would then find the target and pass the precise range and azimuth to the plotting room at the gun battery by phone. Two operators were required, one for the range position and one for the azimuth position. The radar operators would continue to track the target and update the plotting room as the range and azimuth changed. Once the shore battery fired, the SCR-296-A could detect the water splashes of near misses and provide adjusting information by voice commands such as "300 short" or "500 long".

SCR-582 to SCR-296-A Radar, Seacoast Battery Communications Paths.

In operation, the range accuracy was about ± 30 yards while azimuth accuracy was about ± 0.20 degree under the best conditions. The set had a dependable range of 20,000 yards on a destroyer size target when properly sited between 150 to 500 feet above sea level.

The operating crew consisted of 5 men plus a power plant operator and radar maintenance man.

The Radar track data was provided by telephone to support Battery Townsley as the primary battery and to secondary batteries including Battery 129 .

Closure

The SCR-296A Radar equipment was declared obsolete by AG letter on 17 Jan 1946. The Tower and radar equipment were to be disposed of while the buildings were to be retained.

Physical Plant

Wildcat Ridge Radar Site Plan.
Wildcat Ridge Radar Site Coverage.

The transmitter building for this radar set was built as a dug-in type reinforced concrete structure with the antenna tower supported by four concrete piers on the reinforced concrete roof. The transmitter building site was then backfilled so that the roof was covered with a layer of earth and only the back entrance, the four antenna supports, a vent, an escape hatch and cable conduits were exposed.

The radar site was located on the Wildcat Military Reservation which was the location of two fire control base end stations that provided part of a manual fire control system that relied on optical observation. The fire control stations supported Battery Townsley and Battery 129. Also on the post were 60" searchlights #1 and #2 of the San Francisco searchlight defenses. These were the furthest north searchlights of the harbor defenses.

Electrical power was provided by two 25kw generators each housed in a separate building with a 1000 gallon underground fuel tank.

Communications facilities on the Wildcat Ridge Military Reservation included a 15 pair telephone cable southward to the Bolinas fire control switchboard and from there on to the Hill 640 Military Reservation fire control switchboard and then on a 25 pair cable to Fort Cronkhite and then on to the HDCP at Fort Scott. The landline communications were backed up by an emergency radio network.

Current Status

Part of Point Reyes National Seashore in Marin County, California. Several hiking trails cross the former reservation and the Wildcat Camp is located on the site of the reservation. No visible remains of the Military reservation facilities.

Public access via hiking and biking trails. No direct automobile access.


Location: Wildcat Ridge in Marin County, California.

Maps & Images

Lat: 37.97635 Long: -122.79236

See Also:

Sources:

  • U.S.Army, Supplement to the Harbor Defense Project Harbor Defenses of San Francisco, (CCA-P-SFB), 15 Nov 1945, CDSG
  • RCW-Corrected to May 1944, CDSG.

Links:

Visited: No


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