NORTH AMERICAN RADAR

By 1950 the United States was gripped by an intense, paranoid fear of sudden attack by Russian bomber flying the shortest, trans-polar route via the north pole and Canada. To detect this onslaught, three lines of early warning radar stations were foisted upon the Canadian people: the Pinetree Line, which ran east to west just north of the US border, the Mid-Canada Line, and the arctic Distant Early Warning Line.
The first phase of the Pinetree Line was completed in 1954 and the whole system by 1962. The Mid-Canada Line, which was a Dopler radar fence, ran along the 55th parallel and was completed a few years later.
The DEW line, many of the stations on which were built in the most inhospitable region on earth, followed the 66th parallel and was completed by 1961. Extensions to the DEW line eventually gave continuous radar cover from the Aleutian Islands to Scotland, via Greenland and Iceland.
In reaction to a new generation of Russian bombers, and to the threat of nuclear cruise missiles, the DEW Line was upgraded with fifteen new FPS117 phased-array radars between 1985 and 1994, and re-named the North Warning Line.

ABOVE and BELOW
Typical DEW Line radar stations
in sub-arctic Canada

ABOVE: Up until the introduction of SAGE in the mid to late 1950s radar control and reporting in the US was done by voice-telling and manual plotting using proceedures similar to those employed in the British ROTOR system.

BELOW: The introduction of the computerised SAGE (Semi-Automatic Ground Environment) system called for large, centralised Combat and Direction Centres like this one at Topsham.

BELOW LEFT: SAGE called for eight Combat Centres (similar to ROTOR SOCs) and over thirty sub-Sector Direction Centres. Most Combat Centres were to be colocated with Direction Centres but this was later abandoned. This picture shows the dual complex at Syracuse under construction

LEFT: interior and exterior views of SAGE Direction Centre powerhouse, showing Worthington diesel generators