CFS Sioux Lookout Canadian Forces Station Sioux Lookout ( ADC ID : C - 16 ) is a closed General Surveillance Radar station . It is located west of Sioux Lookout , Ontario . It was closed in 1987 . It was operated as part of the Pinetree Line network controlled by NORAD . " I think with proper research you will find that it was not named Sioux Lookout but Sam Lake . I can remember , as a kid in nearby Hudson , civilians that worked at the base had a paper stuck to the inside of the windshield behind the mirror with the initials SL on it . The base sits on the shore of Sam Lake , a tiny pothole lake and across highway 664 from Sam Lake is Ralph Lake . They were probably named for the Warner Bros cartoon characters Ralph the wolf and Sam the sheep dog . As the crow flies Sioux Lookout is closer to the base but by road the base is just about equidistant between Hudson and Sioux . . " History . As a result of the Cold War and with the expansion of a North American continental air defence system , Sioux Lookout was selected as a site for a United States Air Force ( USAF ) radar station , one of the many that would make up the Pinetree Line of Ground - Control Intercept ( GCI ) radar sites . Construction on the Sioux Lookout base began in 1952 and was completed by 1953 . The base was manned by members of the USAF ' s Air Defense Command ( ADC ) 915th Aircraft Control and Warning Squadron , being known as Sioux Lookout Air Station . In April 1953 of the following year , operations began at the unit ' s permanent home . The station was equipped with AN / FPS - 3 C , AN / FPS - 502 , AN / FPS - 20 A , AN / TPS - 502 , and AN / FPS - 6 B radars . As a GCI base , the 915th ' s role was to guide interceptor aircraft toward unidentified intruders picked up on the unit ' s radar scopes . These interceptors were based at Duluth International Airport in Minnesota . In the early 1960s , the USAF relinquished control of the base to the Royal Canadian Air Force ( RCAF ) . This was part of an arrangement with the United States that came as a result of the cancellation of the Avro Arrow . Canada would lease 66 F - 101 Voodoo fighters and take over operation of 12 Pinetree radar bases . Upon hand - over on 1 October 1962 , the operating unit was re - designated 39 Aircraft Control and Warning Squadron and the base , RCAF Station Sioux Lookout . Radars at the station were also upgraded to the following : In 1963 , radar operations at 39 Squadron were automated by the Semi Automatic Ground Environment ( SAGE ) system , and the station became a long - range radar site . It would no longer guide interceptors but only look for enemy aircraft , feeding data to the Duluth Air Defense Sector SAGE DC - 10 Direction Center of the 30th NORAD Region . As a consequence of the change , the operating unit was once again renamed , this time as 39 Radar Squadron . In 1966 , Sioux Lookout was reassigned to the 29th NORAD Region , and in October 1967 , Sioux Lookout was once again re - designated . This time , the change was due to the creation of the Canadian Armed Forces , the new tri - service organization that absorbed the RCAF , RCN and the Canadian Army . 39 Radar Squadron , RCAF Station Sioux Lookout , became simply Canadian Forces Station ( CFS ) Sioux Lookout . In yet another organizational change , Sioux Lookout was again switched to the 23d NORAD Region in 1969 . Beginning in 1983 it began reporting to Canada West ROCC . The last major change came in the 1980s . After a lengthy review by both the Canadian and American defence ministries , it was decided to modernize the North American air defence infrastructure . DEW Line equipment was upgraded and the Line was renamed the North Warning System . With this newer equipment , it was decided to close most Pinetree Stations . CFS Sioux Lookout was thus disbanded in July 1987 . Today , the station remains standing , although thought as deserted and apparently unused , it is privately owned and now used as a homestead .