WWV and WWVH are shortwave radio stations operated by the National Institute of Standards and Technology, a United States government agency. WWV is located in Fort Collins, Colorado, and WWVH is located in Hawaii.
Originally, WWV was located in Washington, D.C. from 1920 to 1931, College Park, Maryland from 1931 to 1932, and Greenbelt, Maryland from 1932 to 1966. On December 1, 1966, the station moved to its present location in Fort Collins, Colorado. WWV broadcast local Eastern Standard Time until April 1967 when they switched to Greenwich time. WWV was originally operated by the National Bureau of Standards, the predecessor agency to today's National Institute of Standards and Technology. WWVH started broadcasting in 1948. 
These radio stations broadcast the time in Coordinated Universal Time, which corresponds to the time in Greenwich, England. These stations also broadcast maritime storm alerts, solar conditions, and other announcements. The two stations can be distinguished from each other by their announcers. WWV has a male announcer and WWVH has a female announcer.
WWV operates on 2500, 5000, 10,000, 15,000, and 20,000 kilohertz. WWVH operates on 2500, 5000, 10,000, and 15,000.