G-Shock GW-300CFJ-3 - Manual (Page 3)

Operation Guide 2689
3
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.
• For information about selecting a Home City, see “Setting the Time and Date Manually”.
Home City
TYO
LAX, DEN, CHI, NYC
Transmitter
Either the Mt. Otakadoya signal (40kHz) or the Mt.Hagane signal (60kHz)
Fort Collins, Colorado signal
1000km
Mt. Hagane
(60kHz)
500km
1000km
500km
Transmitter Location
Mt. Otakadoya
(40kHz)
• 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.
Fort Collins
3000km
1000km
Transmitter Location
• 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.
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 using
built-in antenna.
Watch decodes
received data and
converts it to time
data.
Time is adjusted
according to time
data.
Signal data
Cesium
atomic clock
Transmitter Long-wave time
calibration signal
Internally
Decode
Watch
Time 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 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.
How a Radio-controlled Watch Works
❚ 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 Mode” for more information about
the transmitter mode.
❚ To trigger reception manually
In the Timekeeping Mode, hold
down the D button for about
two seconds until the watch
beeps.
• This indicates that manual receive
has started. The “
” icon flashes
on the display while signal
reception is in progress.
❚ To stop signal reception
Press the D button.
• 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 on the display also indicates successful signal reception.
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 will return to the normal timekeeping screen
automatically if you do not perform any operation for about one
or two minutes.
❚ Receive icon
The receive indicator cycles from
“Unstable” through “Stable” as
shown below while reception is in
progress. How far it cycles depends
on the signal strength. Keep the
watch in a location where reception
is stable while reception is in
progress.
Unstable Stable
• Even under optimum reception conditions, it can take about 10
seconds for reception to stabilize.
• Use the receive icon 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.
Receive icon
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.
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 Among or near buildings
Next to a household appliance
or office equipment
(TV, speaker, fax, PC,
mobile phone, etc.)
Inside a vehicle
(automobile, train, plane, etc.)
Near mountains In a location where there is radio
interference
(construction site, airport, etc.)
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 receive (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.
❚ 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 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.
• 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.