G-Shock GW-300BTJ-10JR User Manual
MA0302-A
USER’S GUIDE 2609/2639
The following explanation covers the radio-controlled timekeeping function only.
For other functions, go to the download page for Module 2608 or 2638,
which are the export models that have the same functions, except for radio-controlled timekeeping.
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.
Time Calibration Signal
The time calibration signal is the same one used by TV and radio
stations to keep accurate time and sound their time signals. The
standard time data of the time calibration signal is controlled by
cesium beam atomic clock.
Time data
After the watch receives the Japan 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
Inside a vehicle
(automobile, train, plane, etc.)
In a location where there is
radio interference
(construction 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.
Near high-voltage lines
Next to a household
appliance or office equipment
(TV, speaker, fax, PC, etc.)
Near mountains
Calibration Signal
The Japanese calibration signal (Call Sign: JJY) is maintained by
the independent Japan Ministry of Posts and Telecommunications
Communication Research Laboratory (CRL). It is a long wave
signal 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.
Though the calibration signal is normally transmitted 24 hours
a day, transmission may be interrupted occasionally due to
maintenance, lightening, etc.
Transmitter
Cesium
atomic clock
Long-wave time
calibration signal
Watch
Receiving the Calibration Signal
There are two methods you can use to receive the time calibration
signal.
Auto reception (Reception is performed automatically at 2:00,
3:00, 4:00, and 5:00 each morning.)
Manual reception (You initiate reception using a button
operation.)
The watch is set up for auto reception at the factory, so all you
need to do is to place it in a location that allows good reception
each night.
Setting Up to Make Reception Easier
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 the
watch 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.
Signal data
Decoding
Time data
Inside the watch
Signal received using
built-in antenna.
Watch decodes
received data
and converts it
to time data.
Time is
adjusted
according to
time data.
Reception Range
This watch is designed to receive the standard time calibration signal of Japan (JJY) or of the United States (WWVB). The signal that is
received depends on the current Home City setting.
When this Home City is selected: You can receive this signal
Either the Mt. Otakadoya signal (40kHz) or the Mt. Hagane signal (60kHz)
Fort Collins, Colorado signal
500km
1000km
1000km
Mt. Otakadoya
(40kHz)
Receive icon
Receive indicator
Transmitter Location
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.
Receive Icon and Indicator
While reception is in progress, the
icon and the receive indicator
cycle from “Unstable” through
“Stable” as shown below. How far
they cycle depends on the signal
strength. Keep the watch in a
location where reception is stable
while reception is in progress.
Module 2609
Unstable Stable
Module 2639
Unstable Stable
Even under optimum reception conditions, it takes at least
10 seconds before reception starts.
Use the receive icon and receive indicator to check
reception status and to determine the best location for
signal reception.
Note that weather, the time of day, surroundings, and other
factors can all affect reception.
Transmitter Locations
Mt. Hagane
(60kHz)
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, and the time of day can make reception impossible even when you are within range of
the transmitter.
Best reception is possible late at night.
500km
Time Required for Reception
Signal reception takes anywhere from about two to six minutes.
Note that when “AUTO” is specified as the frequency selection
mode, signal reception can take up to 12 minutes.
* See “Specifying the Transmitter Selection Mode in Japan” for
more information.
Triggering Reception Manually
In the Timekeeping Mode:
Hold down the
about two seconds.
The watch beeps and reception
starts. Ongoing reception is
indicated by the icon and the
receive indicator. See “Receive
Icon and Indicator” for more
information.
To interrupt reception
Press the
All other buttons besides D are disabled during signal reception.
When reception is successful
The watch terminates reception and adjusts the current time. Next
it beeps and then displays the date and time the adjustment was
performed.
The icon and the receive indicator remain on the display to
indicate that reception was successful. The icon is cleared
from the display each day at 3:00 a.m.
When reception fails
The watch does not adjust its current time setting, and displays
“ERR” instead.
The display also return to the normal timekeeping screen
automatically if you do not perform any operation for about one
or two minutes.
DD
D button for
DD
DD
D button.
DD
3000km
1
USER’S GUIDE 2609/2639
The following explanation covers the radio-controlled timekeeping function only.
For other functions, go to the download page for Module 2608 or 2638,
which are the export models that have the same functions, except for radio-controlled timekeeping.
Viewing the Last Reception Date and Time
In the Timekeeping Mode:
DD
Press the
D button.
DD
This displays the date and time
that signal reception was
complete and the current time
and date were adjusted.
To return to the timekeeping
screen, press the D button
again.
The display also returns to the
normal timekeeping screen
automatically if you do not
perform any operation for about
one or two minutes.
Important!
The calibration signals received by this watch include two data
groups: an hour-minute-second group and a year-month-day group.
Both the hour-minute-second
group and year-month-day group
were not received. It will not
remain on the display if only the
hour-minute-second group is
received.
Not displayed
Hour-minute-second group and yearmonth-day group received
Hour-minute-second group only received
If only the hour-minute-second group is received, the Timekeeping
Mode date at the time of reception is recorded as the last
reception date.
displayed
not displayed
Calibration Signal Reception Precautions
Auto reception can be performed while the watch is in the
Timekeeping Mode or World Time Mode only.
Operating any button while auto reception is in progress will
cause the watch to beep and then exit the receive operation.
Make sure you are within the range of the calibration signal
transmitter before performing the receive operation. Remember
that geographic contours, nearby buildings, the season, and 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 signals transmitted in Japan and
the United States only. Note that you will need to make your own
adjustments when using this watch outside of Japan or the United
States, 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 signal using the
calibration signal for some reason, timekeeping accuracy is within
±15 seconds per month.
Strong electrostatic charge can cause timekeeping error.
Signal reception is cancelled if an alarm starts to sound while it is
being performed.
The watch's calendar shows dates up to the year 2099.
Attempting a receive operation after that causes an error.
Turning Auto Reception On and Off
Display the setting screen.
1.
Hold down the
for two seconds.
AA
A button
AA
2. Display the transmitter selection mode setting screen.
CC
Press the
C button three
CC
times.
3. Turn auto reception on or off.
DD
Press the
D button to
DD
toggle auto reception ON
and OFF.
4. Exit the setting screen.
AA
Press the
A button twice.
AA
This exits the setting screen and returns to the normal
timekeeping screen.
The display also will return to the normal timekeeping screen
automatically if you do not perform any operation for about
two or three minutes.
Troubleshooting
Cannot perform manual reception.
Possible Cause: The watch is not in the Timekeeping Mode
Corrective Measures: Perform manual reception while a time
The icon is not displayed even though auto reception is
turned on.
Possible Cause: A single receive operation was not
Corrective Measures: Check to make sure the watch is in a
or World Time Mode.
The Home City is set to a city other than
TYO (Tokyo), NYC (New York), CHI
(Chicago), DEN (Denver), or LAX (Los
Angeles).
screen is on the display in the Timekeeping
Mode or World Time Mode only.
Change Home City To TYO (Tokyo), NYC
(New York), CHI (Chicago), DEN
(Denver), or LAX (Los Angeles).
successful.
Both the hour-minute-second group and
year-month-day group were not received.
The watch is not in the Timekeeping Mode
or World Time Mode when an auto
reception time is reached.
You performed manual reception, which
clears the icon from the display.
location where it can receive the signal.
Place the watch in a location where
reception conditions are good.
Make sure that the watch is in the
Timekeeping Mode or World Time Mode
during the auto reception times.
The icon disappears from the display
whenever you change the current time
setting manually.
Specifying the Transmitter Selection Mode in Japan
When Tokyo (TYO) is selected as the Home City, you can select
either of two different transmitters for reception.
1. Display the setting screen.
Hold down the
for two seconds.
AA
A button
AA
2. Select the transmitter selection mode you want.
DD
Press the
D button.
DD
3. Exit the setting screen.
AA
Press the
A button twice.
AA
This exits the setting screen and returns to the normal
timekeeping screen.
The display also will return to the normal timekeeping screen
automatically if you do not perform any operation for about
two or three minutes.
Time setting is incorrect following signal reception.
Possible Cause: Summer time is turned on or the wrong
Corrective Measures: Turn off summer time so the DST
If you cannot receive the calibration signal or if the current time
setting is incorrect after signal reception, check the current setup
of the watch. The following are the watch's factory default
settings, which are configured automatically whenever you have
the battery of the watch replaced.
Auto Receipt
Transmitter
Home City
Summer Time
Home City is selected.
indicator is not on the display.
Configure the watch for the correct DST
setting and Home City setting.
On
Auto Japan transmitter select
(40kHz/ 60kHz)
To kyo
Auto switching in accordance
with signal data
AUTO
With this setting, the watch automatically selects either the
Otakadoya Mountain signal (40kHz) or the Hagane Mountain
signal (60kHz), whichever is strongest.
* The frequency first used by the watch is the one that was
last successful.
40
With this setting, the watch always receives the Otakadoya
Mountain signal (40kHz).
60
With this setting, the watch always receives the Hagane
Mountain signal (60kHz).
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