Skip to main content
U.S. flag

An official website of the United States government

Official websites use .gov
A .gov website belongs to an official government organization in the United States.

Secure .gov websites use HTTPS
A lock ( ) or https:// means you’ve safely connected to the .gov website. Share sensitive information only on official, secure websites.

Time Signal Broadcast Stations

NIST distributes frequency and time signals by radio, referenced to UTC(NIST), to users in all 50 states. Radio Stations WWV, in Ft. Collins, Colorado, and WWVH located on the island of Kauai in Hawaii, operate a combined total of ten transmitters in the HF (high frequency) spectrum. They broadcast standard carrier frequencies, audio announcements of time, and related information. They also serve as space weather beacons that assist scientists involved in ionospheric research. Radio Station WWVB, also located in Ft. Collins, operates in the LF (low frequency) portion of the spectrum at 60 kHz. Its signals synchronize tens of millions of radio-controlled clocks and also serve as a frequency reference.

WWV building
Radio Station WWV
Credit: NIST
Image of WWVB radio antennas
Radio Station WWVB
Credit: NIST


Fort Collins (WWV, WWVB)

Hawaii (WWVH)

Created April 27, 2023, Updated May 3, 2023