Atomic Sync: Watch Time Sync

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About this app

Atomic Sync is a handy time sync tool for compatible radio-controlled watches.

With Atomic Sync, you can send your phone’s current time to a supported radio-controlled watch using an audible encoded signal from your phone speaker. The app is useful when normal radio reception is weak, unavailable indoors, or difficult to receive in your location.

Atomic Sync supports multiple regional time signal formats, including JJY 40, JJY 60, WWVB, DCF77, MSF, and BPC. Simply choose the signal format supported by your watch and start a close-range transmission.

Key features:
• Send phone time to compatible radio-controlled watches
• Support for JJY 40 / JJY 60, WWVB, DCF77, MSF, and BPC formats
• Uses your phone’s current local time
• Simple protocol selector for different regional signal formats
• Transmission status and frame progress display
• Helpful for close-range sync attempts when normal radio reception is weak
• Designed for watches that support regional radio time signal formats

Atomic Sync does not transmit real 40-77.5 kHz radio waves. It generates an audible encoded time signal for close-range synchronization attempts. Sync success may vary depending on your watch model, speaker volume, watch position, room noise, and protocol compatibility.

If you use a radio-controlled watch and need a simple way to try syncing it with your phone time, Atomic Sync gives you a practical tool right in your pocket...
Updated on
Jun 4, 2026

Data safety

Safety starts with understanding how developers collect and share your data. Data privacy and security practices may vary based on your use, region, and age. The developer provided this information and may update it over time.
This app may share these data types with third parties
Location and Device or other IDs
No data collected
Learn more about how developers declare collection
Data is encrypted in transit
Data can’t be deleted