Operation Guide 2891
How a Radio-controlled Watch Works
Reception Ranges
With this setting, the watch automatically selects either the Mt. Otakadoya signal (40kHz) or the Mt. Hagane signal (60kHz), whichever is strongest.
Location
Reception is difficult and may even be impossible in the locations described below. Avoid such locations when performing signal reception.
What is a radio-controlled watch?
Your
Signal is received by
Long-wave
Watch decodes received data and
Signal data 
converts it to time data.
| Decode |
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Cesium | Time data | Time is adjusted | |
| according to time | ||
atomic clock Watch | Internally | ||
data. |
After the watch receives the Standard Time signal, it performs internal calculations to determine the current time. Because of this, there may be an error of up to one second in the displayed time.
Calibration Signal
•The Japanese calibration signal (Call Sign: JJY) is maintained by the National Institute of Information and Communications Technology (NICT). It is transmitted 24 hours a day from the Mt. Otakadoya transmitter (40kHz) located in
Though the calibration signal normally is transmitted 24 hours a day, transmission may be interrupted occasionally due to maintenance, lightning, etc.
Transmitter Location | 1000km | |
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| Mt. Otakadoya |
500km | 500km | (40kHz) |
Mt. Hagane |
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(60kHz) |
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1000km
•Under optimum conditions, the calibration signal should be receivable up to 1,000 kilometers from the transmitter. Note that the wave is relatively weak at distances greater than 500km, so reception may be poor at long distances.
•Geographic contours, nearby buildings, the season, the time of day, can even make reception impossible even when you are within range of the transmitter.
•Best reception is possible late at night.
•You should think of your watch operating like a radio or TV when it is receiving the calibration signal.
Among or near buildings | Near |
Inside a vehicle (automobile, | Next to a household appliance or |
train, plane, etc.) | office equipment (TV, speaker, |
| fax, computer, cell phone, etc.) |
In a location where there is
radio interference (construction Near mountains site, airport, etc.)
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| If you are experiencing problems with reception, move away |
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| from the types of locations described above to a location with |
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| better reception, and try again. |
Receiving the Calibration Signal | Time Required for Reception |
| Receive Icon | Receive Icon |
| ❚ To view the last reception date and time | |
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There are two methods you can use to receive the time calibration signal. | Signal reception takes anywhere from about two to seven minutes. | The receive indicator cycles from |
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| In the Timekeeping Mode, press the Dbutton six times to | ||
• Auto receive (Reception is performed automatically at | • Under certain conditions, signal reception can take as long as 14 minutes. | “Unstable” through “Stable” as |
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| enter the Receive Mode. | |||||
midnight, 1:00, 2:00, 3:00, and 4:00 each morning.) | • See “Configuring Auto Receive Settings” for more |
| shown below while reception is in |
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• Manual receive (You initiate reception using a button operation.) | information about auto receive. |
| progress. How far it cycles depends |
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| • This displays the date and time when signal reception was last suc- | |
• Once auto receive is successful on a particular day, the auto receive |
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| on the signal strength. |
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❚ To perform manual receive |
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| cessful, and the current time and date were last adjusted. | |||
operation for subsequent times are not performed for that day. |
| Keep the watch in a location where |
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| • To return to the Timekeeping Mode, press the D button again. | ||||
| reception is stable while reception is |
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• If reception is not successful for any of the normal auto receive operations | 1. In the Timekeeping Mode, press the D button six |
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in progress. |
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| • The display will return to the normal timekeeping screen | ||||
shown above, auto receive is performed one more time at 5:00 a.m. |
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• The watch is set up for auto receive at the factory, so all you need to | times to enter the Receive Mode. |
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| automatically if you do not perform any operation for about one or | |
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| two minutes. | |
do is to place it in a location that allows good reception each night. |
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2. Hold down the Cbutton |
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❚ To position the watch for optimum reception |
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| Reception Time | ||
for about two seconds. |
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Remove the watch from your wrist and place it somewhere so its top | • The watch will beep and |
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(12 o’clock, where the antenna is located) is facing approximately in |
| Unstable |
| Stable |
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the direction of the signal transmitter. Keep it away from metal objects. | reception will start. The display |
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| will flash and the receive icon |
| • Even under optimum reception conditions, it can take about 10 |
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| ( | ) will start to cycle through | (2 seconds) | seconds for reception to stabilize. |
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| its numbers. |
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| ❚ To interrupt reception |
| • Use the receive icon to check reception status and to | (6 times) | |||
Resin Band | Press the C button. |
| determine the best location for signal reception. |
| Reception Date | ||
| • Note that weather, the time of day, surroundings, and other | ||||||
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| • All other buttons besides C are disabled during signal reception. | factors can all affect reception. |
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| When reception is successful |
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| The watch terminates reception and adjusts the current time. Next it |
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| beeps and then displays the date and time the adjustment was performed. |
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| • The “ | ” icon (with all numbered segments visible) on the display |
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| also indicates successful signal reception. |
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Metal Band | When reception fails |
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| The watch does not adjust its current time setting and displays |
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• Orienting the watch so it is sideways to the transmitter makes it | “ERR” when signal reception is unsuccessful for some reason. |
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more difficult to receive the signal. | • The display will return to the normal timekeeping screen automatically |
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• Do not move the watch while it is receiving the calibration signal. | if you do not perform any operation for about one or two minutes. |
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