The advantages of G-SHOCK watches are obvious:
Once they have been set to the relevant time zone, they always display the exact local time and automatically switch between summer and winter time. Here you can read about the technology and how your watch receives the time signals.
What is the point of time radio-controlled watches?
A time radio-controlled watch always gives you the accurate time. Always: because the watch receives a regular signal. Accurate: because the time is calculated by atomic clocks, the most precise timekeepers in the world. No setting, no adjusting, always on time.
What kind of signal is transmitted?
In Germany, the time signal DCF77 is transmitted on the frequency 77.5 kHz. MSF is the signal from Great Britain and WWVB is the signal in the USA - both are transmitted with a frequency of 60 kHz. The two Japanese signals JJY are transmitted with a frequency of 40 kHz and 60 kHz. The Chinese signal BPC is sent on a frequency of 68 kHz. The radio-controlled watch decodes the relevant signal and displays the exact local time.
What happens when I go on a journey?
The transmitter in Mainflingen near Frankfurt can supply both Germany and large parts of Europe with the exact time. When G-SHOCK radio watches are set to the relevant time zone, they show the exact local time for the current location. Some G-SHOCK models are equipped with the new radio technology Multiband 6 and receive signals in North America and Japan, as well as many parts of Canada, Mexico and China.
The displayed time matches your computer's system clock - not the actual atomic clock's time.
Where does the time signal come from?
Atomic clocks are the most accurate clocks in the world. In Germany, the official time is established in the Physkalisch-Technische Bundesanstalt in Braunschweig the national meteorology institute. In Great Britain, the National Physical Laboratory in Teddington near London is in charge of this task.In the USA, this job is carried out by the National Institute for Standards and Technology (NIST) in Fort Collins/Colorado. In Japan, the official time is determined by the Communications Research Laboratory (CRL) in Tokyo. In China, the time is sent by the National Time Service Center.
How accurate are atomic clocks?
Atomic clocks show practically no deviation from ideal time. During the course of a million years, they will in theory "stray" by about one second. As a comparison: a quartz wristwatch errs by a couple of seconds a month, mechanical watches - no matter how noble - by much more.
How does the time reach the watch?
The time calculated by atomic clocks is sent to radio towers.In Germany, the tower is located in Mainflingen near Frankfurt. In Great Britain, the tower can be found in Anthorn. In the USA, the tower is located in Fort Collins. The tower in Japan can be found in Fukushima in the North East and Fukuoka in the South West. The tower for China is located in Shangqiu. The radio tower in Mainflingen reaches a watch with radio technology within a radius of up to 1,500 km depending on the model. A special feature of some CASIO radio watches is that they are equipped to receive signals from all six transmitters.
