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1939: The beginning of the long dash…

The Story


On Nov. 5, 1939, CBC Radio began network broadcast of the Dominion Observatory official time signal. Generations of CBC Radio listeners have set their watches and clocks to the familiar daily refrain, aired promptly at 12:59 p.m. eastern standard time. Early mariners and surveyors relied on an accurate time signal to calibrate their instruments for navigation and mapping. More recently, precise timekeeping is essential for the coordination of communications, transportation and power distribution networks. As demonstrated by this 1974 CBC Radio clip, the announcement introducing the time signal has changed very little since it began.

Medium: Radio
Broadcast Date: Feb. 4, 1974
Announcer: Alan Maitland
Duration: 0:51

Did You know?


• The Meteorological Service of Canada was the nation's official timekeeper until the mid 1930s, at which point the responsibility was transferred to astronomers at the Dominion Observatory. In 1941 this arrangement was formalized by an order-in-council designating the observatory the source of official time for the country. Physicists at the National Research Council took over responsibility in 1972.

• In addition to the daily CBC broadcast, the NRC's time signals are broadcast continuously by short wave radio station CHU.

• In 1958 Canada's official reference standard was the first in the world to be based on the vibrations of a cesium atom. Astronomically determined time was replaced with the cesium atomic clock. In 1967 the cesium atom was formally recognized as the new international unit of time.

• Cesium atomic clocks are known as the world's most accurate timekeepers. The National Research Council developed their cesium-V frequency standard into the world's first high-accuracy primary cesium clock, which began operation in 1975.

• Oddly enough, trains were instrumental in the early days of Canadian radio and, subsequently, time signals. Constantly competing with Canadian Pacific Railways, Canadian National Railways turned to broadcasting as a means of promotion in 1923. CNR Radio was established as Canada's first network, broadcasting the nation's time signals from Ottawa and Moncton. The signal continued transmission when the Canadian Radio Broadcasting Commission took over CNR Radio in 1933, and when the CRBC became CBC in 1936.

• The official time signal is the longest-running feature on CBC Radio.

• The current announcement accompanying the broadcast reads as follows: "Now for the National Research Council official time signal: the beginning of the long dash following ten seconds of silence indicates one o'clock eastern standard time."


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