スマホで電波時計の時刻を合わせる JJY Simulator

Easily synchronize your radio-controlled clock with your smartphone.

This radio-controlled clock time synchronization utility solves problems like "My radio-controlled clock doesn't receive a signal in the back of the room" or "I'm overseas but want to synchronize my Japanese radio-controlled clock."

This app uses the sound (harmonics) emitted from your Android smartphone's speaker to generate a simulated signal that closely resembles the standard radio wave "JJY (40kHz)" transmitted from Mt. Otakadoya in Fukushima Prefecture for the East Japan area. Even in the back of a room or basement where radio waves are difficult to reach, you can force your radio-controlled clock to synchronize using just your smartphone.

💡 Main Features and Characteristics

• Designed specifically for 40kHz (Mt. Otakadoya)

• Accurately simulates the 40kHz standard radio wave widely used in the East Japan area. A single-frequency-only design for easy use.

• Synchronize anywhere with just your smartphone

• Easily synchronize your time even in places where radio waves are normally unavailable, such as reinforced concrete apartments, offices without windows, and basements.

• Simple one-tap operation

• Just launch the app. No complicated settings are required; anyone can use it intuitively.

🛠 How to Use (5 Steps)

1. Put the radio-controlled clock into "Radio Wave Reception Mode (Forced Reception State)".

2. Turn up your smartphone's volume to "Maximum" or near maximum.

3. Launch this app, "JJY Simulator".

4. Bring your smartphone's speaker as close as possible to the internal antenna of the radio-controlled clock (usually on the top or back of the clock).

5. Wait for a few minutes, and if the hands of the radio-controlled clock move correctly, synchronization is complete!

⚠️ Tips and Precautions to Increase Reception Success Rate
• Using Earphones (Recommended):
If you can't receive the signal well through your smartphone's speaker, connect wired earphones to your smartphone and wrap the earphone cord around the radio-controlled clock's body. The cord acts as an antenna, dramatically increasing the reception success rate.

• Synchronization Time:
Due to the specifications of radio-controlled clocks, it takes about 3 to 15 minutes for the time to be perfectly synchronized. Please keep your smartphone and watch still and wait in a quiet environment while receiving the signal.
• Individual watch variations:
Some watches with very robust noise suppression, or certain overseas-made radio-controlled watches, may not be able to properly recognize the simulated signal.

📈 Recommended for:

• Those whose radio waves do not reach the back of their rooms at home
• Those using radio-controlled clocks in windowless shops, offices, or underground environments
• Those who find it troublesome to take their watch to a window every time they change the battery