How A Radio-Controlled Watch Works; Reception Ranges - Casio 2931 Operation Manual

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Selecting Beeper or Vibration Alert
You can select either a beeper or vibration as the alert that is
performed for the alarm, hourly time signal, or Timer Mode
progress alert and time up alarm.
Beeper: The watch emits audible beeps.
Vibration: The watch vibrates silently and a VIB indicator appears
on the display.
Vibration
Indicator
• While vibration alert is selected, the watch does not emit any
operation confirmation tones when you change modes, etc.
❚ To select beeper or vibration alert
1.
GMT Differential
In the Timekeeping Mode,
A
A
hold down the A
A
A button
City Code
for about two seconds
until the city code and
GMT differential start to
flash. This is the setting
screen.

Reception Ranges

This watch is designed to receive the standard time calibration signal of Japan (JJY) or of the United States (WWVB), depending on its
current Home City setting.
• For information about selecting a Home City, see "Setting the Home City Time and Date". For information about city codes, see the
"GMT Differentials".
Home City
TYO, OSA
Either the Mt. Otakadoya signal (40kHz) or the Mt. Hagane signal (60kHz)
LAX, DEN, CHI, NYC
Fort Collins, Colorado signal
1000km
Transmitter Location
Mt. Otakadoya
500km
(40kHz)
500km
Mt. Hagane
(60kHz)
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.
Operation Guide 2931
2.
A
A
A button.
Press the A
A
• This causes VIB (vibration
alert) or BEEP (beep alert) to
flash on the display.
3.
Vibration Indicator
Press the D
D
D button to
D
D
toggle the alert setting
between VIB and BEEP.
• The VIB (vibration) indicator
appears when vibration alert it
selected. No indicator is
displayed while beep alert is
selected.
4.
When the alert setting you want is displayed, press the
A
A
A
A
A button twice to exit the setting screen.
• The display also will exit the setting screen automatically if
you do not perform any operation for about two or three
minutes.
Transmitter
Transmitter Location
3000km
1000km
Fort Collins
• Under optimum conditions, the calibration signal should be
receivable up to 3,000 kilometers from the transmitter. Note
that the wave is relatively weak at distances greater than
1,000km, so reception may be poor at long distances.

How a Radio-controlled Watch Works

What is a radio-controlled watch?
Your radio-controlled watch is designed to receive a time
calibration signal that contains standard time data, and adjust its
current time setting accordingly.
Signal is received by
built-in antenna.
Transmitter
Long-wave time
calibration signal
Watch decodes
received data and
Signal data
converts it to time
data.
Decode
Time data
Time is adjusted
Cesium
according to time
atomic clock
Internally
Watch
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.
Location
Reception is difficult and may even be impossible in the locations
described below. Avoid such locations when performing signal
reception.
• You should think of your watch operating like a radio or TV when it
is receiving the calibration signal.
Among or near buildings
Near high-voltage lines
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.)
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.
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 Tamura-gun, Fukushima
Prefecture, and from the Mt. Hagane transmitter (60kHz) located
on the border between Saga Prefecture and Fukuoka Prefecture.
• The U.S. calibration signal (Call Sign: WWVB) is transmitted by
the National Institute of Standards and technology from Fort
Collins, Colorado.
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 standard
wave 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.
http://jjy.nict.go.jp
• Note that the above URL is subject to change.
Receiving the Calibration Signal
There are two methods you can use to receive the time calibration signal.
• Auto receive (Reception is performed automatically at
midnight, 1:00, 2:00, 3:00, and 4:00 each morning.)
• Manual receive (You initiate reception using a button
operation.)
• Once auto receive is successful on a particular day, the auto receive
operation for subsequent times are not performed for that day.
• If reception is not successful for any of the normal auto receive operations
shown above, auto receive is performed one more time at 5:00 a.m.
• The watch is set up for auto receive at the factory, so all you need to
do is to place it in a location that allows good reception each night.
❚ 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 facing
approximately in the direction of the signal transmitter. Keep it
away from metal objects.
Resin Band
Metal Band
• Orienting the watch so it is sideways to the transmitter makes it
more difficult to receive the signal.
• Do not move the watch while it is receiving the calibration signal.
4

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