WWVB, America's Atomic Clock Radio Station

Somewhere near Fort Collins, a low-frequency radio signal pulses outward at sixty kilohertz, twenty-four hours a day, carrying the most precise time available to the American public. This is WWVB, operated by the National Institute of Standards and Technology. The station went on the air on the Fourth of July, nineteen sixty-three, which was already July fifth in Coordinated Universal Time, built here because the alkaline soil north of Fort Collins conducts radio waves with exceptional efficiency.

The signal is designed to reach most of the continental United States and southern Canada. In nineteen sixty-five NIST added a time code to the broadcast, making it possible to build clocks that set themselves automatically from the signal. Today most radio-controlled clocks and wristwatches in North America use WWVB transmissions, synchronizing to the cesium fountain atomic clocks that NIST uses to define national time.

If your car clock reset itself correctly after you changed the battery, this station is probably why.