Web Multiband Simulator

Reproduce radio time signals to sync radio-controlled watches.
Please star the project on GitHub if you find it helpful!

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Select a protocol
Time source
Broadcasting

Global Signal Coverage

Radio-controlled clocks automatically synchronize to one of these regional longwave transmitters. Select the one that suits your watch's supported frequencies and your location/timezone for the best results.

Map of global atomic clock signal coverage
BPCChina
68.5 kHz
WWVBUSA
60 kHz
DCF77Germany
77.5 kHz
MSFUK
60 kHz
JJYJapan
40 & 60 kHz

Pick a Time source in the time card (below the UTC/DST badges). NTP synced lets the page pull accurate time from the network automatically. If you keep System time, make sure your device's clock is accurate — check it against time.is or an NTP server such as pool.ntp.org — so the simulator transmits the correct time signals.

Use a headphone or the computer's built-in speaker. Maximize the volume for better reception, and place your radio-controlled clock close to the speaker.

Press Start Transmitting, set your clock to its manual sync/receive mode, and wait. Because these protocols transmit one frame per minute, it usually takes several minutes for a clock to successfully decode the time.