NIST broadcasts the time https://www.nist.gov/pml/time-and-frequency-division/time-distribution/radio-station-wwv
Both WWV and WWVH announce the time of day each minute in Coordinated Universal Time, and make other recorded announcements of general interest on an hourly schedule, including the Global Positioning System (GPS) satellite constellation status. Because they simultaneously transmit on the same frequencies, WWV uses a male voice in order to differentiate itself from WWVH, which uses a female voice.
Source: https://en.wikipedia.org/wiki/WWV_(radio_station)
Station identification: WWV
WWVH is the Hawaii location
automatic-setting 'atomic' clocks use radio WWVB https://www.nist.gov/pml/time-and-frequency-division/time-distribution/radio-station-wwvb/help-wwvb-radio-controlled
Wikipedia has a technical article
GPS has its own page