WWV

WWV is a shortwave radio time signal station operated by the National Institute of Standards and Technology (NIST) in the United States. It provides highly accurate time and frequency references and is used by radio amateurs, scientists, engineers, and automated systems to calibrate equipment and synchronize clocks. The station is notable for its long-running service as a public standard of time and frequency.

Location and transmission: The WWV transmitter complex is located at a site near Fort Collins, Colorado. WWV broadcasts continuous time signals on multiple shortwave frequencies, currently including 2.5, 5, 10, 15, 20, and 25 MHz. In addition to a spoken time announcement each minute, the station transmits a digital time code that encodes the current Coordinated Universal Time (UTC) and provides a precise timing reference for receivers worldwide.

Reception and use: The WWV signal can be received globally under favorable ionospheric conditions, though reception quality depends on frequency, time of day, and solar activity. The station is widely used to discipline local clocks, calibrate test equipment, and verify receiver performance. Its time signals are also employed in academic research and by hobbyists who rely on a trusted time standard for experiments and synchronization tasks.

History and status: WWV is part of NIST’s time and frequency services and has operated as a standard reference for many decades. It exists alongside other time signals such as WWVB (on 60 kHz) and other NIST time dissemination services, forming a network that supports timekeeping and metrology across various applications.

See also: WWVB, NIST time and frequency services.