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Necessary cookies Necessary cookies enable core functionality such as security, network management, and accessibility. Analytics cookies We utilise Google Analytics cookies to help us to improve our website by collecting information on how it's used. Home Resources Questions and answers Why is my radio-controlled clock not showing the correct time?
Questions and answers Why is my radio-controlled clock not showing the correct time? What can you do to ensure you receive the correct time? Improving reception Assuming that the signal is still on, the following suggestions, in order of increasing difficulty, may help to improve reception of the MSF radio signal: Consult the manual for the clock before turning it on.
The 60 kHz signal is located in a part of the radio spectrum called LF, which stands for low frequency. This is an appropriate name, because the FM radio and TV broadcasts that we are accustomed to listening to use frequencies thousands of times higher.
The lowest frequency received by any of the other radios in your house is probably kHz, the bottom of the AM broadcast band. Even that frequency is nearly 10 times higher than the WWVB signal. At 60 kHz, there isn't enough room on the signal bandwidth to carry a voice or any type of audio information. Instead, all that is sent is a code, which consists of a series of binary digits, or bits, which have only two possible values 0 or 1.
These bits are generated at WWVB by raising and lowering the power of the signal. They are sent at a very slow rate of 1 bit per second, and it takes a full minute to send a complete time code, or a message that tells the clock the current date and time. When you turn a radio controlled clock on, it will probably miss the first time code, so it usually takes more than one minute to set itself sometimes 5 minutes or longer depending on the signal quality and the receiver design.
Once your radio controlled clock has decoded the signal from WWVB, it will synchronize its own clock to the message received by radio. Before it does so, it applies a time zone correction, based on the time zone setting that you supplied. While a few users like their clocks to display UTC ham radio operators, for example , most prefer to display local time. This means that the time in your area is corrected by the number of hours shown in the table. Once your radio controlled clock has synchronized, it won't decode the signal from WWVB again for a while.
Most clocks only decode the signal once per day, but some do it more often for example, every 6 hours. Those that decode the signal just once per day usually do it at midnight or in the very early hours of the morning, because the signal is easiest to receive when it is dark at both WWVB and at the site where the clock is located.
In between synchronizations, the clocks keep time using their quartz crystal oscillators. A typical quartz crystal found in a radio controlled clock can probably keep time to within 1 second for a few days or longer.
Therefore, you shouldn't notice any error when you look at your clock display, since it will appear to be on the right second, even though it has probably gained or lost a fraction of a second since the last synchronization. The red areas on the coverage maps below show where a WWVB radio controlled clock should be able to synchronize. Note that the red area is largest at night, and smallest in the daytime click on the map to see a larger image.
These maps are based on a field strength of microvolts per meter, which in theory should be a large enough signal for most receivers to work with. In fact, some receivers have much better sensitivity 20 or 30 microvolts per meter. All that you have to do is set the time zone, and the clock can display a very accurate time. The only thing more accurate that you can carry around easily is a GPS receiver , which derives atomic clock accuracy in real time from the atomic clocks in orbiting GPS satellites.
Sign up for our Newsletter! Mobile Newsletter banner close. Mobile Newsletter chat close. Mobile Newsletter chat dots. Mobile Newsletter chat avatar. Well, once the watch has been set to the relevant time zone, they always display the exact local time. How good is that? Regular signal reception ensures that your watch will always show the correct time.
The exact time is transmitted to the watch from atomic clocks which are practically the most precise watches in the world. Basically, No setting, no resetting, and always on time.
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