Skip to main content
Cold War Radar

Introduction to the Line

Radar lines.jpg

1957 image showing the radar chains in Canada.  Note the Pinetree Line, closest to the American border

The plan for the Pinetree Line was created by CONAC (Continental Air Command) and the RCAF (Royal Canadian Air Force) and began in 1948. 

It was comprised of 33 stations, 17 of them American staffed.  60% of the stations would be early warning while the other 40% would be to help navigate interceptors. 

The Pinetree Line ran the 49th parallel, in areas where pinetrees grew and Canada did about 1/3 of the building.

It was able to give an extra 2 hours warning time at the most, but this was still very important. With this time, the Americans could get about 40% of their interceptors flying, though the RCAF's number would be less.

The systems of radar to be used in the Line were AN/MPS-4 or AN/TPS-10 as height finder, and AN/CPS-5 or AN/TPS-1B as search radar.  The buildings would be located above the ground.

In 1951 there was an agreement between the two countries that said the United States would cover a lot of the expense and that the radars would connect to the Permanent Radar System in the United States.  22 of the original stations would be paid for by the United States. 

It was originally focused more on the east because this where most of the industry was but in the 1950s importance moved to Strategic Air Command bases.  Therefore, between 1957-1964, holes in the Line in the Prairies and in Quebec and northern Ontario were filled.

These stations relied on communication systems which also helped civilians.  Where able, the Pinetree Line drew on the communication lines that already existed, although they had to be further supported or updated.  This was done by engineers from CN, CP, and Bell and the networks continued until the fall of the Soviet Union.  At the bequest of the Canadian Department of Defence, one system was built that was no longer up to date in 1965 and Bell purchased it for $4 million.

In the early 1960s it was updated with new radar stations.  Their purpose was to reach further north, and make use of new technology in radar, communications, and computers.  These improvements were done due to Soviet bomber improvements.  New long-range stations included Chbougamau Quebec, Moosonee Ontario, Gypsumvill Manitoba, Yorkton, Dana, and Alask in Saskatchewan, and Penhold Alberta.

The old stations were improved too, receiving new long-range radars and height-finder radars.  This gave coverage of 200 miles and upwards of 50 000 feet and was compatible with SAGE.

Canadians began to staff 11 radar stations that had been American and by 1963 all stations were in Canadian hands.

Taking over these stations was part of the agreement after the Arrow failure and began with Beausejour Manitoba on October 1961 and continued to Lowther Ontario July 1, 1963.  Also taken over were Barrington, Nova Scotia, Ramore, Pagwa, Armstrong, and Sioux Lookout Ontario, Saskatoon Mountain Alberta, and Baldy Hunghes, Puntzi Mountain, and Kamloops British Columbia.

About 6 stations were shut down before 1965 but the majority continued into the 1970s.


Pinetree Line
Introduction to the Line