Signal Setter: Radio Watches
WWVB JJY DCF77 MSF time signal
Only for iPhone
$1.99
iPhone
Set most radio-controlled watches and clocks indoors or abroad: your phone sends the station's signal with exact network time. One price, no subscription, no ads.
Your radio-controlled watch or clock sets itself from a time station: WWVB in the US, JJY in Japan, DCF77 in Germany, MSF in the UK. Indoors, abroad or out of range, it never hears one. Signal Setter sends the station's time signal from your phone, and most radio-controlled watches and clocks can pick it up and set themselves. Reception depends on the model, so hold the watch close to the phone's speaker or to wired earphones.
PICK THE CITY, NOT THE STATION
Choose the city your watch is set to. Signal Setter picks the station a watch set to that city listens for. You can still pick any station yourself, including JJY on 40 or 60 kHz.
THE TIME IT SENDS IS RIGHT
The time comes from a network time server, corrected for your phone's own clock, and every minute of the code starts exactly on the minute. The app shows how far your phone's clock was off. Each station's own time zone and summer-time rules are applied, so your watch adds its own offset correctly. Without a connection it falls back to the phone's clock and tells you.
LOCAL TIME FOR WATCHES FROM JAPAN
A watch sold in Japan that only receives JJY always shows Japan time, wherever you are. Turn on "Send my local time" and it sets itself to the time where you are instead.
SEE THE SIGNAL AS IT GOES OUT
The session screen shows the time the signal is sending, every second of the minute's code as it plays, and the status of each minute of the session.
HOW TO PLACE YOUR WATCH
A short guide shows where the antenna usually sits and how to hold the phone's bottom speaker against it. Volume all the way up; the app will not start below full volume, because the watch picks up only a faint radio echo of the sound.
ONE PRICE
Pay once. No subscription, no ads, no account, no tracking. The only network request asks a public time server for the time.
GOOD TO KNOW
• Works with many radio-controlled watches and clocks. Reception depends on the model, where its antenna sits and nearby interference, so some watches never pick it up this way.
• Put the watch into its receive mode first. Most finish within 3 to 10 minutes.
• Use the phone's speaker or wired earphones. Bluetooth audio rarely works.
• The tone is high-pitched and plays at full volume. Keep the phone away from your ears.
Ratings & Reviews
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The developer, FatCouple OÜ, indicated that the app’s privacy practices may include handling of data as described below. For more information, see the developer’s privacy policy .
Data Not Collected
The developer does not collect any data from this app.
Accessibility
The developer has not yet indicated which accessibility features this app supports. Learn More
Information
- Seller
- FatCouple OU
- Size
- 2.3 MB
- Category
- Utilities
- Compatibility
Requires iOS 17.0 or later.
- iPhone
Requires iOS 17.0 or later.
- iPhone
- Languages
English and 2 more
- English, German, Japanese
- Age Rating
4+
- 4+
- Copyright
- © 2026 FatCouple OU
