Time signal station
Stations that broadcast the exact time from atomic clocks, with ticks every second and spoken or coded announcements.
What does it sound like?
Regular clock-like ticks, one per second, with a voice announcing the time each minute.
Who uses it?
National standards laboratories, for example WWV (Colorado) and WWVH (Hawaii) in the US, RWM (Russia), BPM (China).
Where and when can I hear it?
WWV on 2.5, 5, 10, 15 and 20 MHz (plus an experimental 25 MHz signal) and WWVH on 2.5, 5, 10 and 15 MHz; RWM on 4996, 9996 and 14996 kHz. Canada's CHU went off the air on June 22, 2026.
Hear it live
- Northern Utah WebSDR #1 (Northern Utah, USA) · 5,000 kHz AM
WWV broadcasts 24 hours a day on 2.5, 5, 10, 15 and 20 MHz, plus an experimental 25 MHz signal. - Northern Utah WebSDR #2 (Northern Utah, USA) · 10,000 kHz AM
WWV broadcasts 24 hours a day on 2.5, 5, 10, 15 and 20 MHz, plus an experimental 25 MHz signal. - University of Twente WebSDR (Enschede, the Netherlands) · 77.5 kHz CW
DCF77, Germany's time signal from Mainflingen, runs around the clock. Heard as a steady tone that dips at the start of each second, except the last second of each minute.
These are free public receivers run by other people; we only link to them. You'll hear the signal only if it's on the air right now and conditions carry it to that receiver, so if it's quiet, try another time. Links last reviewed 2026-09-28.
The science
WWV and WWVH use ordinary double-sideband AM, with frequencies and timing traced to atomic standards. Each second is marked by a 5-millisecond tick at 1000 Hz from WWV or 1200 Hz from WWVH, the 29th and 59th seconds are skipped so listeners can find the minute, and each minute opens with an 800-millisecond tone. A time code is sent one bit per second on a 100 Hz subcarrier, and both stations announce UTC by voice every minute, WWVH first and then WWV.
Why use it?
Anyone with a basic shortwave radio can get accurate time and a reference frequency for checking equipment, with no internet or satellite needed. Broadcasting on several frequencies at once means at least one usually gets through whatever the time of day and propagation, and WWV's signal on 5, 10 and 15 MHz runs at 10 kilowatts.
Lore
WWV received its call letters in October 1919 and in May 1920 broadcast Friday evening music concerts from Washington, D.C., months before KDKA's famous election-night broadcast. Voice time announcements began on January 1, 1950, and the station moved to Fort Collins, Colorado, on December 1, 1966.
What do the decoded parts mean?
- Time: The official time, usually given in UTC (Coordinated Universal Time).
Easily confused with
- Morse code (CW): a beacon's Morse ID repeats but doesn't tick every second