Casio MA0811-EA User Manual

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There are two methods you can use in order to receive the time calibration signal. 

Up to six times a day (Midnight, 1:00, 2:00, 3:00, 4:00, 5:00 a.m.)

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A for about two seconds 

•  The second hand moves to “READY”. 

•  The hour and minute hands continue to operate normally. 

•  The second hand moves to “WORK”. 

•  The hour and minute hands continue to operate normally. 

•  Do not perform any watch operations while signal reception is in 

progress (second hand at “WORK”).

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•  When the receive operation is successful, the second hand will move 

to “Y” or “YES”, the watch will adjust its time, and then the second hand 
will return to normal operation after about three minutes.

•  If the receive operation is not successful, the second hand will move 

to “N” or “NO”. The second hand will return to normal operation after 
about three minutes.

■ To cancel a manual receive operation

■ To position the watch for optimum reception

Remove the watch from your wrist and place it somewhere so its top (12 o’clock side, where the antenna 
is located) is pointing approximately in the direction of the signal transmitter. Keep the watch away from 
metal objects.

•  Orienting the watch so it is 

sideways to the transmitter 
makes it more diffi cult for it to 
receive the signal. 

•  Do not move the watch while it is 

receiving the calibration signal.

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Signal reception normally takes anywhere from about two to seven minutes. Under certain signal 
conditions however, the receive operation can take as long at 14 minutes. 

1.  The watch cannot receive the time calibration signal.
•  Is the signal being transmitted? 
  Though the time data of the Japanese calibration signal (Call Sign: JJY) is maintained by the Japan 

Standard Time Group of the National Institute of Information and Communications Technology (NICT), 
it sometimes may be interrupted for periodic maintenance work, or because of lightning or other 
problems. 

•  Are you within the reception range of a transmitter? 

•  Is there something in the immediate area that may be interfering with reception? 
  Even if you are within the reception range of a transmitter, electrical noise or objects between you and 

the transmitter can interfere with reception. Avoid such areas during signal reception.

•  After the watch receives the time calibration signal, it performs an internal decoding process before 

updating its time setting. Because of this, the time setting may be off slightly (within one second).

3.  Time calibration signal reception is successful, but the current time setting is wrong. 
•  Are the home positions of the hands off?
 Refer 

to 

“Home Position Adjustment” and check the hand home positions.

•  Pressing any button while auto receive is in progress will cause the watch to exit the receive operation. 

•  Make sure you are within the range of a calibration signal transmitter before performing the receive 

operation. Remember that geographic contours, nearby buildings, the season, or the time of day can 
make reception impossible even when you are within range of the transmitter. 

•  Proper reception may be impossible if there is something blocking the signal. If reception is 

unsuccessful, try again. 

•  This watch is designed to adjust its current time setting in accordance with the calibration signal 

transmitted in Japan only. Note that you will need to make your own adjustments when using this watch 
outside of Japan, or in any area that is outside the range of one of the receivable time calibration signal 
transmitters. 

•  When the watch is unable to adjust its time using the calibration signal for some reason, timekeeping 

accuracy is within ±20 seconds per month. 

•  Strong electrostatic charge can cause timekeeping error.

A radio-controlled watch is designed to receive a time calibration signal that contains standard time data 
and adjust its current time setting accordingly.

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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 (40 
kHz) located in Tamura-gun, Fukushima Prefecture, and from the Mt. Hagane transmitter (60 kHz) located 
on the border between Saga Prefecture and Fukuoka Prefecture. 

The time data of the Japanese calibration signal (Call Sign: JJY) is maintained by the Japan 
Standard Time Group of the National Institute of Information and Communications Technology 
(NICT). 
Note that transmission of the calibration signal may be interrupted occasionally due to 
maintenance, lightning, etc.
For more information, visit the website of the Japan Standard Time Group of the National Institute 
of Information and Communications Technology (NICT) at the following URL.

•  Note that the above URL is subject to change.

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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 make reception impossible 

even when you are within range of the transmitter.

•  Best reception is possible late at night. 

Reception is diffi cult and may even be impossible in the locations described below. Avoid such locations 
when performing signal reception. 
•  You should think of your watch as operating like a radio or TV when it is receiving the calibration signal. 

If you are experiencing problems with reception, move away from the types of locations described 
above to a location with better reception, and try again.