How a radio-controlled watch works, Operation guide 3346, What is a radio-controlled watch – G-Shock GW-1310RCJ-3AJR User Manual

Page 3: Calibration signal, Reception range

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Operation Guide 3346

3

To specify the illumination duration

1.

In the Timekeeping Mode,
hold down the

A

A

A

A

A

button

for about one second.

This will cause your city code
to flash on the display.

2.

Press the

C

C

C

C

C

button three

times to display the
flashing seconds count.

3.

Press the

B

B

B

B

B

button to

toggle the illumination
duration between about
1.5 seconds ( indicator)
and 2.5 seconds
(

indicator).

4.

After the setting is the way
you want, press the

A

A

A

A

A

button to exit the setting
screen.

The watch will also exit the
setting screen automatically if
you do not perform any
operation for about two or
three minutes.

City Code

Seconds

(3 times)

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

Cesium
atomic clock

Transmitter

Internally

Decode

Watch

Time data

Signal is received
using built-in antenna.

Watch decodes
received data and
converts it to time
data.

Time is adjusted
according to time
data.

Long-
wave time
calibration
signal

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 National Institute of Information and Communications
Technology (NICT). 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.

How a Radio-controlled Watch Works

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 “Configuring Home Time Settings”. For information about city codes, see the “World Time
City Code List”.

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

Japan Transmitter
Locations

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.

U.S. 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.

Geographic contours, nearby buildings, seasonal conditions, 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.

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