Trans Canada Microwave or Trans-Canada Skyway was a microwave relay system built in the 1950s to carry telephone and television signals from Canada's east coast to its west coast. Built across the nation, the towers ranged in height from nine metres high, to one in northern Ontario that was over 100 metres high. The system included 139 towers spanning over 6,275 kilometres and cost $50 million (equivalent to $555,000,000 in 2025).
History
Origins Canada was among the first countries to implement telephone service using a microwave relay system, when in 1948 a link between Nova Scotia and Prince Edward Island opened with a capacity of 23 telephone lines. This was followed in 1952 by a radio system between Halifax and Saint John, New Brunswick, with 46 channels. Telephone usage grew explosively in the post-war era in Canada, and the country soon had the third largest number of telephones in the world despite its small population. More importantly, Canadians used their phones much more than any other nation, making an average of 411 calls per year. Existing long-distance lines would quickly be saturated, especially in the major markets. Studying the issue, Bell Canada decided to skip the use of coaxial cable connections being installed in the US, and concluded a microwave relay was the solution for rapidly improving the number of connections in these markets. In 1952, the Canadian Broadcasting Corporation (CBC) issued a contract for a nationwide relay to send television and radio signals coast-to-coast. The contract was sent to both Bell and CNCP Telecommunications, the joint Canadian National Railway-Canadian Pacific Railway company that shared telegraph services. The Department of Transport, responsible for licensing bandwidth allocations in Canada, tried to have the two groups build a single shared network. CNCP agreed to the proposal, but Bell rejected it, at which point CNCP dropped their interest in the project. The Cabinet stepped in and passed a law stating that no company would be allowed a monopoly, at which point CNCP began plans for their own network concentrating in the heavily populated areas east of Manitoba.
First links With Bell as the only remaining contender for the CBC network, plans began for the first major link from Toronto to Montreal via Ottawa. After discussions between Bell's president Thomas Wardrope Eadie and CBC's president Alphonse Ouimet, the network would also include a link to Buffalo, New York, to allow US television programming to be rebroadcast into the Toronto market. The link went live on 15 January 1953, and the rest of the network to Montreal was completed in May the same year. The network was extended to Quebec City the next year, with branch links northward from the mainline to Peterborough and Barrie, and a short link southward to Kingston. The obvious value of the system, especially the Toronto-Montreal link, led Eadie to consider expanding the network into a trans-Canada system carrying television, teletype and telephone signals.
The network used the Bell Labs TD-2 system, built locally by Northern Electric, operating at base frequency of 4 GHz. It could carry twelve 10 MHz wide signals, producing six channels in both directions. In US service at that time, any one channel carried one television channel or up to 600 telephone conversations encoded using frequency division multiplexing (FDM). Bell upgraded their systems to add FDM to the television channels as well, allowing two 4 MHz signals to be carried in a single 10 MHz channel. They also added the ability to mix one television signal with addition telephone signals, which Bell referred to as "double decking". To lower the cost compared to the TD-2 system being deployed by AT&T in the US, Bell Canada used double decking where possible, simplified power supplies, and added a microwave frequency switch that allowed the same antennas to be used for broadcast or reception depending on the immediate needs of the network.
Cross-country expansion The first links in Ontario and Quebec were within areas served entirely by Bell, but this was not the case for the rest of the network, where smaller regional telephone companies held local monopolies. This required additional planning, including deciding how to split up the costs and revenues. This was carried out within the Trans-Canada Telephone System company, which had formed to handle the same sorts of issues for land-line cost sharing and long-distance fees. Construction of the cross-country network began on 8 March 1955. The system required a total of 139 stations, spaced at an average of 25 miles (40 km). The stations in the original core typically used squared-off parabolic reflectors, while later additions used horn-reflector antennas. Sites in the east were relatively easy to locate as they were already heavily developed, but in northern Ontario and especially the Rocky Mountains, aerial surveys were used to pick likely spots. Once selected, a temporary tower made of aluminium would be manually lifted into place and a small circular reflector hoisted to test the link and find the minimum altitude that gave it a good signal. Getting the equipment into position could be an enormous task; in one case at Morrissey Ridge in British Columbia, it took two months to bulldoze a road to the proposed site. Given this sort of delay, a new system was created in which a single workman would travel to the site and alert the next tower he was in place using a walky talky, then used a mirror to reflect the sun onto the next station to test the line of sight. This was sometimes done from a helicopter. The towers themselves were sized to the local terrain, with the largest, just over 350 feet (110 m) high, outside North Bay.
… excerpt ends here. Continue reading the full article.
