The Lashup Radar Network was a United States Cold War radar netting system for air defense surveillance which followed the post-World War II "five-station radar net" and preceded the "high Priority Permanent System". ROTOR was a similar expedient system in the United Kingdom.
Background
United States electronic attack warning began with a 1939 networking demonstration at Twin Lights station NJ, and 2 SCR-270 radar stations during the August 1940 "Watertown maneuvers" (NY). When "Pearl Harbor was attacked, [there were 8 CONUS] early-warning stations" (ME, NJ, & 6 in CA), and Oahu's Opana Mobile Radar Station had 1 of 6 SCR-270s. CONUS "Army Radar Station" deployments for World War II were primarily for coastal anti-aircraft defense, e.g., L-1 at Oceanside CA, J-23 at Seaside OR (Tillamook Head), and B-30 at Lompoc CA; and "the AAF...inactivated the aircraft warning network in April 1944." In 1946 the Distant Early Warning Line was "first conceived—and rejected". By 1948 there were only 5 AC&W stations, e.g., Twin Lights in June and Montauk's "Air Warning Station #3 on July 5 (cf. SAC radar stations, e.g., at Dallas & Denver Bomb Plots).
Radar Fence
The Radar Fence was a planned U.S. Cold War air defense "warning and control system" for $600 million (including $388 million for radars and other equipment) proposed in a report by Maj. Gen. Francis L. "Ankenbrandt and his communications officers" and which was approved by the USAF Chief of Staff on November 21, 1947. The "Radar Fence Plan (code named Project SUPREMACY)" was to be complete by 1953 with 411 radar stations and 18 control centers in the continental United States. Air Defense Command (ADC) rejected Supremacy since "no provision was made in it for the Alaska to Greenland net with flanks guarded by aircraft and picket ships [required] for 3 to 6 hours of warning time", and "Congress failed to act on legislation required to support the proposed system." In the spring and summer of 1947, 3 ADC Aircraft Control and Warning (AC&W) plans had gone unfunded.
Lashup planning
In November 1947 ADC "decided to go ahead with implementation [using] AC&W assets…ADC possessed." The January 1, 1948, Finletter Commission report "while recognizing the need for a radar early-warning system, cautioned against the extraordinary expense of such a system, if constructed, to provide total coverage." The ADC commander "was ordered on 23 April 1948 to establish with his current resources [the initial networks with] AC&W systems in the Northwestern United States, the Northeastern United States, and the Albuquerque, New Mexico, areas, in that priority." The "first air defense division organization", the 25th Air Division, was established October 25, 1948, "at Silver Lake (Everett), Washington", the 26th Air Division was activated at Mitchell Field NY on November 16, and both were transferred to ADC on April 1, 1949.
Lashup deployment
"Lashup I" was a stopgap $561,000 program approved in October 1948 by the ADC commander to expand "the five-station radar net then in existence". Preliminary work began by the end of 1948, and L-1 at Dow Air Force Base was complete in June 1949. In the fall of 1949 a 2nd stage of "additional Lashup stations and heavy radar equipment [was] authorized", and after completed in April 1950 the "Lashup net went into operation" on June 1, 1950. After a mid-July direct telephone line was installed between CONAC headquarters and the 26th Air Division HQ ("the beginning of the Air Force air raid warning system"); in August "President Truman had a direct telephone line installed between the Air Force Pentagon post and the White House."
Sites in the network
The 44 Lashup radar stations in April 1950 were 23 in the Northeast/Great Lakes areas, 10 in the Pacific Northwest, 5 in/near Southern California, 3 at Albuquerque, 2 at San Francisco, and 1 in Tennessee (Alaska radars were in a separate network.) Stations were geographically grouped by Air Divisions which each had a ground-controlled intercept (GCI) center (e.g., Roslyn Air Warning Station's Manual Control Center in New York).