G-Shock GW-900BJ-4 - Manual (Page 3)

Operation Guide 2839
3
❚ Time Required for Reception
A calibration signal receive operation takes anywhere from about
two to six minutes.
• Note that when “AUTO” (Auto Select) is specified as the transmitter
selection mode, signal reception can take up to 12 minutes.
• See “Signal Reception Settings” for more information.
❚ To perform manual receive
Hold down the D D D D D button for
about two seconds.
• The watch will beep and
reception will start. The signal
receive indicator changes to
while signal reception is in
progress.
❚ To interrupt reception
Press the D D D D 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.
Reception Error (ERR Indicator)
The watch does not adjust its current time setting, and displays
“ERR” when signal reception is unsuccessful for some reason.
• The display will return to the normal timekeeping screen automatically
if you do not perform any operation for about one or two minutes.
How a Radio-controlled Watch Works
Receiving Indicator
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.
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 data
Transmitter
Internally
Decode
Watch
Time data
Long-wave
time calibration
signal
Cesium
atomic clock
Signal is received
using built-in antenna.
Watch decodes
received data
and converts it to
time data.
Time is adjusted
according to 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.
Note that transmission of the standard wave may be
interrupted occasionally due to maintenance, lightening, etc.
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 city codes, see the “Selecting Your Home City”.
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)
Mt. Otakadoya
(40kHz) 500km
1000km
500km
Transmitter Location
• 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.
3000km
1000km
Fort Collins
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.
• 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.
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.
Receiving the Calibration Signal
There are two methods you can use to receive the time calibration
signal.
• Auto receive (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 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 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.
❚ Receive Icon
The receive icon 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
Near mountains
Inside a vehicle (automobile,
train, plane, etc.)
In a location where there is
radio interference (construction
site, airport, etc.)
Next to a household appliance or
office equipment (TV, speaker,
fax, computer, cell phone, etc.)
Among or near buildings Near high-voltage lines