I didn’t Know That...

Q: I have a clock that sets its own time. How does it do it?

A: The federal government operates a radio station, WWVB, in Fort Collins, Colo., that continually broadcasts the time, as determined by an atomic clock at the site. WWVB is a 50,000-watt station that broadcasts at the low frequency of 60,000 hertz, compared with the typical AM radio frequency of about 1,000,000 hertz. Because of its high power and low frequency, the station can cover all the continental United States, plus much of Canada and Central America, but can be picked up only with a special receiver. The signal can be picked up with a very small antenna that will even fit in a wristwatch. The station transmits the time once per minute, using a digital format that is sent out at a rate of one bit per second. For more information, visit the station’s Web site at: https://www.boulder.nist.gov/timefreq/stations/wwvb.htm