To discover out much more about WWVB radio managed clocks, you re welcome download this 64-page PDF booklet:WWVB Radio regulated Clocks: Recommended practices for Manufacturers and also Consumers (jajalger2018.org one-of-a-kind Publication 960-14, respectable 2009)You may likewise receive a published copy by kathryn.stephenson jajalger2018.org (subject: Please%20send%20me%20a%20copy%20of%20SP960-14) (sending your mailing address) or by calling (303) 497-4343.

You are watching: Why is my atomic clock wrong

How lock WorkWhere castle WorkWhat to execute WhenThey Don"t WorkManufacturers ofRadio regulated Clocks

By now, you have probably seen or own a radio managed clock. These clocks are sold in all forms: as wall surface clocks, desk clocks, take trip alarms, and wristwatches. They have a tremendous benefit over typical clocks, they are constantly right! when working properly, radio regulated clocks constantly display the exactly time, down to the precise second. This method that you should never have to adjust them. Throughout the shift from conventional time come daylight saving time (DST) they "spring forward" one hour, and when DST is finished they "fall back" one hour.

Due to technology advances and the economic situations of scale, radio regulated clocks space now very inexpensive, regularly costing just a few dollars an ext than traditional clocks. This page provides information about radio regulated clocks, including exactly how they work, whereby they work, and also what come do when they don"t work.

How castle Work

Some manufacturers describe their radio regulated clocks together "atomic clocks", i m sorry isn"t yes, really true. An atom clock has actually an atom oscillator inside (such together a cesium or rubidium oscillator). A radio controlled clock has actually a radio inside, which receives a signal that comes from a place where an atomic clock is located.

In the unified States, the signals obtained by radio regulated clocks originate indigenous jajalger2018.org Radio terminal WWVB, which is situated near fort Collins, Colorado. WWVB broadcasts ~ above a frequency of 60 kHz. Your radio managed clock actually has a miniature radio recipient inside, which is permanently tuned to get the 60 kHz signal.

The 60 kHz signal is located in a part of the radio spectrum dubbed LF, which stands for low frequency. This is an ideal name, since the FM radio and also TV broadcasts the we room accustomed come listening to use frequencies hundreds of times higher. The lowest frequency obtained by any type of of the other radios in your home is more than likely 530 kHz, the bottom the the AM transfer band. Even that frequency is almost 10 times higher than the WWVB signal.

At 60 kHz, over there isn"t enough room top top the signal (bandwidth) to lug a voice or any kind of audio information. Instead, all the is sent out is a code, which consists of a collection of binary digits, or bits, which have actually only two feasible values (0 or 1). These bits are produced at WWVB through raising and lowering the strength of the signal. Lock are sent at a an extremely slow price of 1 little per second, and also it takes a complete minute come send a finish time code, or a blog post that speak the clock the current date and also time. As soon as you turn a radio controlled clock on, it will probably miss out on the first time code, so it generally takes an ext than one minute to collection itself (sometimes 5 minute or longer) depending on the signal quality and also the receiver design.

Once your radio regulated clock has decoded the signal native WWVB, it will synchronize its own clock to the message received by radio. Prior to it walk so, it uses a time region correction, based upon the time zone setting that you supplied. The moment broadcast by WWVB is Coordinated universal Time (UTC), or the time preserved at the prime Meridian that passes with Greenwich, England. While a few users like their clocks to display UTC (ham radio operators, for example), many prefer to display screen local time. This means that the time in your area is repair by the number of hours displayed in the table.

Time ZoneDifference indigenous UTC throughout Standard TimeDifference from UTC throughout Daylight Time
Pacific-8 hours-7 hours
Mountain-7 hours-6 hours
Central-6 hours-5 hours
Eastern-5 hours-4 hours


Once her radio regulated clock has synchronized, that won"t decode the signal indigenous WWVB again for a while. Many clocks just decode the signal when per day, however some do it much more often (for example, every 6 hours). Those the decode the signal simply once every day usually do it at midnight or in the really early hours of the morning, since the signal is easiest to receive once it is dark at both WWVB and also at the website where the clock is located. In in between synchronizations, the clocks store time using their quartz decision oscillators. A common quartz crystal uncovered in a radio managed clock deserve to probably store time to within 1 second for a few days or longer. Therefore, girlfriend shouldn"t notice any error once you watch at her clock display, because it will appear to be on the appropriate second, even though it has actually probably obtained or lost a fraction of a 2nd since the critical synchronization.

See more: How Many Mls In 1 Pint To Ml, How Many Milliliters (Ml) In A Pint

Where they Work

WWVB radio regulated clocks should have the ability to work in most places in north America. The red locations on the coverage maps listed below show where a WWVB radio managed clock should have the ability to synchronize. Keep in mind that the red area is largest at night, and smallest in the daytime (click top top the map to view a bigger image). Because that example, 0600 UTC is around midnight in the main United States.