Editing Mid-Canada Line (section)

===Finalizing the plans===

As the experiments continued it became clear that by using taller masts, {{convert|350|feet}} tall, the radar stations could be located further apart, up to {{convert|90|km}}. This reduced the number of stations required. Nevertheless, the price rose, now estimated at about $120,000,000. Although their final report was not yet ready, the SEG put in an interim report in June and it was approved by cabinet by the end of the month.{{sfn|Thorne|1979}}

In their report they outlined the system that would be built almost exactly. It called for eight major ''Sector Control Centres'', numbered from 200 to 900, each of which control up to thirty unmanned radar sites for a total of 90 radar stations.{{sfn|Thorne|1979}} Each of the radar stations consisted of a single tall mast with a number of small dishes in fixed positions on top (typically four, two pointed in either direction), with power and electronics located in a building beside the base of the mast.

The sector control centres were linked using an advanced [[microwave]] communications system developed in part by [[Canadian Armament and Research Development Establishment|CARDE]], which scattered off the [[troposphere]] for long-distance communications. The southernmost site along the eastern portion of the line, at Cape Henrietta Maria on [[Hudson Bay]], was used as the main communications point, with three additional repeater stations transferring data from the line southward to the [[NORAD]] command center in [[North Bay, Ontario]]. The easternmost station at [[Hopedale, Newfoundland and Labrador|Hopedale, Labrador]] was co-located with an existing Pinetree Line station in order to save construction costs.{{sfn|Thorne|1979}}

All aircraft transiting the line would have to file a flight plan through the ''Mid Identification Zone'', or ''MIDIZ'', centred on the fence. The plans also called for the construction of several airbases known as ''Line Clearance Aerodromes'' just to the north of the line, where [[interceptor aircraft]] could operate in times of heightened alert.{{sfn|Thorne|1979}}

At about this time another huge [[civil engineering]] project was underway in Canada, the construction of a cross-Canada microwave relay telephone system. Since many of the [[logistics]] problems were similar, the construction group, led by [[Bell Canada]], was selected as a major contractor for the base construction. Detailed site selection started in 1955, with a major surveying effort running across Canada at the 55th parallel. The sites were so remote that the RCAF had to form up its first all-helicopter squadron in order to provide flight support for the survey teams.{{sfn|Thorne|1979}}