Time flies! 80th anniversary of the National Research Council of Canada time signal

News release

Time signal first heard on the CBC Radio One Network in 1939

November 5, 2019 – Ottawa, Ontario – National Research Council of Canada

Today marks the 80th year that Canadians can tune in to the longest-running but shortest-duration broadcast program on the Canadian Broadcasting Corporation (CBC) Radio One network. It was on November 5, 1939, that the first time signal from the National Research Council of Canada (NRC) was heard on air across the CBC network at exactly 13:00.

A brief history of timekeeping in Canada over the past 96 years

1923: Astronomers at the Dominion Radio Astrophysical Observatory created a shortwave time signal radio station.

1929: The regular daytime transmission began in January. In order to cover Canada in its entirety, the station automatically sent its call sign in Morse code once per hour and pulses were coded to identify the time of day. 

1938: The CHU call letters were first used for Canadian time transmission on the frequencies 3330 kHz, 7335 (7850 since 2009) kHz and 14670 kHz.

1939: The first time the NRC signal was heard on air across the CBC Radio One network.

1970: CHU was transferred from astronomers to physicists at the NRC, putting the Government of Canada’s largest science and research organization in charge of maintaining Canada’s official time.

2019: Almost 50 years later, the NRC continues to be Canada’s official timekeeper.

Quick facts

  • The NRC has used cesium atomic clocks, the world's best timekeepers, since the 1950s. 

  • The NRC operates a cesium fountain atomic clock where atoms of cesium are first launched with laser beams up and then under the force of gravity fall back down like water in a fountain.

  • The NRC offers authenticated Network Time Protocol which enables all Canadians to synchronize their computer clocks with official time.

  • The CHU station is located 15 km southwest of Ottawa at 45° 17' 47" N, 75° 45' 22" W.

  • Since 1990, Canada's official time has been presented by CHU broadcasts through Coordinated Universal Time (UTC) and digital voice announcements have been used.

  • The NRC runs two telephone numbers that announce the time of day. These numbers are accessible to the general public in English: (613) 745-1576 and in French: (613) 745-9426.

Associated links


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