Christmas Valley Air Force Station

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Christmas Valley Air Force Station (1985-2005) - A Cold War U.S. Air Force Radar Station. Established as an Over-the-Horizon Backscatter (OTH-B) radar transmitter site. Located near Christmas Valley, Lake County, Oregon. Closed in 1997.

Christmas Valley AFS Empty Computer Room in Sector 6.
Christmas Valley AFS FPS-118 Transmitters in Transmitter Building.
Christmas Valley AFS Sector 4 Operations Complex, Transmitter Building & Antennas on Right, Communications Terminal on Left.


Christmas Valley Air Force Station was first established in 1985 but the OTH-B radar station it housed never became fully operational. The station was manned by the 777th Radar Squadron, activated on 1 Oct 1988, as a part of the West Coast Sector of the OTH-B radar system, with the associated receivers located at Tule Lake Air Force Station, California. The 777th Radar Squadron operated the sector, with its headquarters at Mountain Home Air Force Base in Idaho. The 2,622-acre Christmas Valley site was located 16 miles east of the Town of Christmas Valley. Some $275 million was spent by General Electric Aerospace on on-site construction.

Christmas Valley AFS Sector Layout.
OTH-B Radar Antenna Configurations.

Initial equipment included the transmitter portion of an FPS-118 OTH-B search radar and some 216 antennas that range from 35 to 135 feet high.

There were actually three FPS-118 transmitters located at Christmas Valley AFS, one for each of the three 60-degree sectors it covered. The three sectors together provide a 180-degree arc of coverage of the west coast from 500 miles out to 1800 miles out from the station. The radar could not cover the first 500 miles because the radar beams skipped over that area. The east coast system provided the same amount of coverage but toward the east from Maine. The sectors were numbered from one to six with 1-3 in the east and 4-6 in the west

The receiver station associated with this transmitter station was located at Tule Lake Air Force Station in California. Data processing took place at the OTH-B Operations Center at Mountain Home AFB, Idaho. Radar track data from the Mountain Home facility would have been fed to the then Northwest Air Defense Sector at McChord Air Force Base near Seattle, Washington and integrated into the air defense picture nationwide.

The Collapse of the USSR

The Cold War ended in 1989 as Soviet states in Eastern Europe overthrew their communist governments. The USSR turned inward, attempting to preserve what remained of the USSR. On 25 Dec 1991, the last Soviet leader, Mikhail Gorbachev resigned and the remaining twelve USSR republics emerged as independent states. It was not clear at the time what would happen as historical events played out but it was clear that the USSR with its massive military capability was devolving and it no longer posed the threat it once had to the West.

With the airborne threat thought to be essentially gone, the need for the new (and very expensive) OTH-B system came into question and the planned sites in Alaska and a southern facing site were outright canceled. Attempts were made to find other missions for the already constructed sites in Oregon, California, Idaho, and Maine but the proposed systems did not warrant the expense of operating the facilities.

Deactivation and Closure

The 777th Radar Squadron was deactivated on 15 Sep 1991 by Tactical Air Command Special Order GB-81 dated 13 Aug 1991. This ended formal military operation of the site with an air defense mission but the equipment remained in place in a "caretaker" status with a 12-month recall ability.

Christmas Valley AFS was next placed in "warm storage" status in October 1997 with the capability to restore operations if necessary. In 2002 it was deactivated and placed in "cold storage" with equipment removed from the site. In 2005 Christmas Valley Air Force Station was officially closed.

Physical Plant

Christmas Valley Air Force Station Structures (edit list)
Number Building Area Currently
3 Transmitter Building All 3 Yes One per sector
3 Water Tank All 3 Yes One per sector
3 Wells All 3 Yes One per sector
3 Transmitter Antenna Arrays All 3 No One per sector
Foundation only remain
6 Sounder Antenna Arrays All 3 No Two towers per sector
Foundation only remain
3 Power Substation All 3 Yes One per sector
Various states of dissassembly
1 Garage S4 Yes
1 Comm Terminal S4 No

Transmitter Buildings

Christmas Valley AFS Sector 5.
Christmas Valley AFS Sector 4 "Cattle Chute Entrance".

There are three transmitter buildings, one in each sector. Sectors 5 and 6 have identical buildings 235 feet in length by 60 feet in width, while the sector four building has an extension on the northeast side that adds 30 feet to the width for a length of some 108 Feet. This adds an additional 1110 square feet to the sector 4 transmitter building. There is also a "cattle chute" type paved entrance to the extension area indicating that this area served as a primary access point and probably contained administrative, security, and possibly communications facilities that served the whole site.

All three of the transmitter buildings are pre-engineered steel structures with insulated, corrugated steel walls and insulated, corrugated steel, gabled roofs, on a concrete foundation. There is a horizontal row of air intake and exhaust grills that span 3/4 of the building's length just below the roofline. The buildings contain no windows, with ventilation provided via the louvered vents and an air-conditioning system. From the photographs above the individual transmitter cabinets and the power tubes atop them appear to be water-cooled hence the large water tank by each building.


Christmas Valley AFS Sector 5 Water Tank & Paet of Power Substation.

Water Tank
A large 75,000-gallon circular steel water storage tank is provided for each sector. Each tank has a diameter of 26 feet and is 21 feet 6 inches in height. Each tank rests on a concrete ringwall and compacted oiled sand foundation. The top of the tank is accessed by way of an exterior steel ladder mounted on the side of the structure.

There are three wells listed on the county records for this site, one for each sector.

FPS-118 Antenna Detail.

Transmitter Antenna Arrays
There are three sets of transmitter antenna arrays, one in each sector placed to the west of each transmitter building. The transmit antenna array is comprised of six distinct subarrays in a line for a total length of 3,630 feet. Each subarray has 12 radiating elements mounted on steel arms connected by steel booms to steel towers. From left to right, the subarrays operate in the A, C, E, D, F, and B bands of the high-frequency radio spectrum. The different frequency bands dictate significant physical size differences in the antenna elements. The steel arms range in length from 19 feet to 77 feet. This, in turn, influences the tower height and gives an uneven or ragged appearance since the tower heights, from left to right, are 135 feet, 75 feet, 45 feet, 55 feet, 35 feet, and 100 feet. Each tower is individually set into a concrete footing. A back screen of corrosion-resistant wire mesh is located behind the antenna elements. The back screen is supported by and is the same height as, the same steel towers that support the antenna elements. A ground screen of galvanized metal mesh runs the full length of the antenna array and extends out 750 feet to the front.

Sounder Antenna Array
The two sounder antenna structures measure ionospheric conditions and are collocated with the transmitter antenna arrays in each sector. The antennas are on identical steel towers 148 feet in height. Each tower is triangular and supported by steel guy wires that radiate outwards in a circular plan from the steel structure.

Christmas Valley AFS Sector 5 Power Substation.

Power Substation
There is a power substation at each of the sectors that distributes power to the transmitter building and other facilities. The substation is a fenced area containing two steel "A" frame dead-end towers, which distribute incoming high voltage electric power to the switchgear and transformers. The yard also contains a three-sided communications tower, conduit support towers, and a small pre-engineered, gable roof, steel building.

Christmas Valley AFS Sector 4 Garage.
Christmas Valley AFS Sector 4 Communications Terminal.

A single garage building was located by the Sector 4 transmitter building. Served as a location to store and maintain equipment quite possibly including emergency vehicles. The garage is a pre-engineered steel structure approximately 20 feet by 20 feet with corrugated steel walls, a steel gable roof, and two overhead rolling steel doors with a door placed between them.

Communications Terminal
A single two-dish satellite communications terminal was located across from the Sector 4 Transmitter building next to the garage.

Christmas Valley Air Force Station AFS Major Equipment List
Search Radar HF Radar Data Systems Comm
Unit Designations
  • 777th Radar Squadron (1988-1991)

Current Status

The former Christmas Valley Air Force Station is now abandoned by the Air Force and all of the external radar equipment has been removed. Most of the high voltage AC switchgear and transformers have been removed and it appears that normal commercial three-phase power is directly wired into the three transmitter buildings and there were some sounds of fans operating during our visit (2018). There was no other activity, vehicles, or people observed during our visit. The three transmitter buildings and other structures remain in place, in good condition and the roads are in good condition. There was no evidence of current ownership.

The Lake County Assessor’s Office records indicate that the State of Oregon currently owns the site containing the three transmitter sites. The 2018 real market value of that 326.39 acre lot is $1,005,112 (Land $110,462 Structures $894,650).

Location: Christmas Valley Air Force Station in Lake County, Oregon.

Maps & Images

Lat: 43.27917 Long: -120.37917

  • Multi Maps from ACME
  • Maps from Bing
  • Maps from Google
  • Elevation: 4,300'

GPS Locations:

See Also:


  • Winkler, David F., Searching the Skies: the Legacy of the United States Cold War Defense Radar Program, USAF Hq Air Combat Command, 1997, 192 pages, Pdf, page 61, 150.
  • Final Environmental Assessment For Equipment Removal At Over-The-Horizon Backscatter Radar – West Coast Facilities, U.S. Air Force Air Combat Command, July 2005, Pdf


Fortification ID:

  • OR0040 - Christmas Valley Air Force Station

Visited: 4 Sep 2018

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