Frequently Asked Questions

FAQ

How should I mount the remote transmitter?

In order to get an accurate reading and to prolong the life of your transmitter, we recommend that you have it in a sheltered area out of the sun and direct rain. Fog and Mist will not affect the sensor, but a soaking in water may. You can mount it outside under an eave of your house or any other suitable place that will keep it out of the sun and rain. Do not wrap the sensor in plastic or seal it in a plastic bag.

What is the maximum distance I can have the remote transmitter from the display?

The maximum open-air distance is 82 feet in a straight line, although you should take into account distance and resistance. Subtract 25-30 feet for an exterior wall or any obstruction that is similar in width or composition. Subtract 15-20 feet per interior wall or any obstruction that is similar in width or composition. (An obstruction would include anything that is between the line of sight like a roof, walls, floors, ceilings, trees, etc.) Also keep your units away from electronic appliances like TV's, microwaves, computers, refrigerators, and speakers.

The transmitter has trouble maintaining a signal through metal siding, stucco walls, and UV glass. You can get the remote transmitter to transmit through these materials, but it will take a little bit of trial and error. Reset the clock as mentioned above and change the angle that the remote transmits through the siding or glass until an outdoor temperature remains on the display for an extended period of time. Keep in mind that the signal from the remote must travel through some space (3 inches of air minimum) before reaching the metal wall or glass window.

My clock has lost its outside temperature reading.

If your outside temperature is not showing on your clock, that may mean that the clock and the transmitter have lost their connection. To reconnect them you must first take the batteries out of both of the units for 15 minutes. First put the batteries back into the transmitter, and then the clock. Let them sit side by side inside your home. When both the indoor and outdoor temperatures show on your clock with the same reading, or within two degrees of each other, then you may put your transmitter back outside. Remember to keep the transmitter out of the direct sun in a dry place. Also keep it away from metal, which can affect the readings. We suggest you use Duracell batteries for optimal performance.

My clock doesn't work.

NIST provides the signal received by your radio controlled clock, but we cannot provide technical support for the clocks themselves. We didn't manufacture them, and we are not familiar with all the models or all of their features. We recommend that you save the instruction sheet that came with your clock, so you can refer to in the future if necessary. Having said that, we can offer a few general tips about what to do if your radio controlled clock isn't displaying the correct time.

My clock doesn't synchronize at all.

Most WWVB radio controlled clocks work great, as evidenced by the hundreds of thousands of units that have been sold throughout the United States. However, if your radio clock or receiver isn't working, we suggest:

• If your clock uses batteries, check them and replace if necessary.

• If you have a desk top unit, try rotating it 90 degrees. If you have a wall clock try mounting it on a wall perpendicular to the one it is currently on (e.g. if it is on a north-south wall try an east-west wall). The antennas are directional and you might be able to improve the signal strength by turning the antenna.

• Place the clock along a wall or near a window that faces Fort Collins, Colorado.

• Locate the clock at least 1 or 2 meters away from any computer monitors, which can cause interference (some monitors have a scan frequency at or near the WWVB carrier frequency of 60 kHz).

• If nothing else works, take the clock outdoors at night and power it down (remove the batteries or unplug it), then power it up again to force it to look for the WWVB signal. If it works outdoors but not indoors, you probably have a local interference problem inside your house or building. If it doesn't work outdoors at night, its probably best to return it and try a different model.

• The shielding provided by a metal building might prevent the clock from working. For example, if you live in a mobile home or a house with steel siding, the clock might not work.

• If you think your clock is defective, ask the manufacturer or dealer about obtaining a replacement.

This information provided by www.tf.nist.gov

My clock switched to DST, but we don't observe DST where I live.

There is most likely an on/off toggle for DST. Turn it off if your area does not observe DST. Contact us about how to do this. If there isn't a way to turn DST off, you may have to change your time zone setting during DST to make your clock display the correct time.

This information provided by www.tf.nist.gov

How do I stop my clock from giving me military time?

The clock has two hour setting features. One feature is the regular time (12) and the second feature is military time (24). As a default the clocks are set for regular time (12). For those that wish to utilize the military (24) feature, you must follow these steps.

First, you repeatedly push the SET button until you see the number (12) for regular time at the top of your LCD screen where your minutes used to be. Second, you push the (+) button once. Your (12) for regular time will switch to (24) for military time. Once you see the (24) do not push any more buttons your clock will update itself.

When does daylight savings time (DST) begin?

Click here http://aa.usno.navy.mil/faq/docs/daylight_time.php

How does my Atomic clock work?

Click here http://www.atomicclocksstore.com/how-do-atomic-clocks-work

Do the clocks run on batteries and if so how long do they last?

Most of the clocks run on AA or AAA batteries. The batteries in the watches and wall clocks usually last about 2 years. The batteries in the digital clocks usually last about a year.

How do I set my time zone?

Each clock is different but in each case you can set each clock & watch to any one of the 4 major US time zones (Eastern, Central, Mountain, Western). When you get your clock, you put in the batteries, set the time zone, and that's it! The clock will take care of the rest. It is also possible to display different US time zones other then the one you are in (convenient if you want four clocks to display the 4 US times zones all at the same time).

What about Canada and Mexico?

The signal does penetrate into areas of southern Canada and Northern Mexico but unfortunately we do not ship outside the US at this time.

Do your clocks work outside of the US, like say in Europe?

Unfortunately not. These clocks were designed only to pick up the US time signal therefore they only work in the US.

Do your clocks work in Alaska or Hawaii?

Unfortunately not. The signal does not reach outside the continuous 48 states.

Will I be able to return the clock if I can't pick up the signal?

Yes. If after 7 days you have followed the instructions and still have not been able to pick up the signal you may return your clock for a full refund.

How long does it take to pick up the signal?

Each case varies depending on the strength of the signal at the time you set up your clock, the clock or watch you have, and your location. In most cases people are able to pick up the signal within a day (usually during the first night when the signal is the strongest).

Will I be able to pick up the time signal where I live?

The government recently upgraded the signal strength from 27,000 watts to 50,000 watts, therefore the signal currently covers the entire continental US. The signal is weakest on the east coast (the I-95 Northeast Corridor) so it may take a little longer to pick up the signal there, and in rare cases some people have not been able to pick up the signal (mostly in commercial metal/brick enclosed buildings with few windows). If you plan to set up some clocks in a brick office building or school we recommend trying out one (just to make sure you can pick up the signal) before you outfit the whole building with atomic clocks. Overall, 98% of our customers have been able to pick the signal.

How do atomic clocks/watches work?

The government owns and operates an "atomic clock" which is located in Colorado. This atomic clock keeps precise time by dropping atoms. It is the most accurate clock in the world and is considered the official US time. The clock is hooked up to a huge radio antenna which sends out a strong radio signal across the entire contiguous US. Our clocks tune into that radio frequency, decode the signal, and automatically set their time to the US atomic clock. The clocks automatically search for the signal at least once a day in order to keep precise time. For more information and a coverage map please go here: http://www.boulder.nist.gov/timefreq/stations/wwvb.htm

How do Atomic Clocks Work?

WWVB Radio Controlled Clocks

To obtain a wealth of information about WWVB radio controlled clocks, please download this 64-page booklet:

WWVB Radio Controlled Clocks: Recommended Practices for Manufacturers and Consumers
(NIST Special Publication 960-14)

You may also receive a printed copy by sending your mailing address to: sp960@boulder.nist.gov or calling (303) 497- 4343.

By now, you have probably seen or own a radio controlled clock. These clocks are sold in all forms: as wall clocks, desk clocks, travel alarms, and wristwatches. They have a tremendous advantage over conventional clocks, they are always right! When working properly, radio controlled clocks always display the correct time, down to the exact second. And you never have to adjust them. During the transition from standard time to 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 economies of scale, radio controlled clocks are now very inexpensive, often costing just a few dollars more than conventional clocks. This page provides information about radio controlled clocks, including how they work, where they work, and what to do when they don’t work.

How They Work

Some manufacturers refer to their radio controlled clocks as "atomic clocks", which isn’t really true. An atomic clock has an atomic oscillator inside (such as a cesium or rubidium oscillator). A radio controlled clock has a radio inside, which receives a signal that comes from a place where an atomic clock is located.

In the United States, the signals received by radio controlled clocks originate from NIST Radio Station WWVB, which is located near Fort Collins, Colorado. WWVB broadcasts on a frequency of 60 kHz. Your radio controlled clock actually has a miniature radio receiver inside, which is permanently tuned to receive the 60 kHz signal.

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 530 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. The time broadcast by WWVB is Coordinated Universal Time (UTC), or the time kept at the Prime Meridian that passes through Greenwich, England. 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.

Time Zone	Difference from UTC During Standard Time	Difference from UTC During Daylight Time
Pacific	-8 hours	-7 hours
Mountain	-7 hours	-6 hours
Central	-6 hours	-5 hours
Eastern	-5 hours	-4 hours

Once your radio controlled clock has synchronized, it won’t decode the signal from WWVB again for a while. Some clocks only decode the signal once per day, others do it more often (like every 4 hours or every 6 hours). Those that decode the signal just once per day usually do it at night, since the signal from WWVB is much stronger once the sun goes down. 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.

Where They Work

WWVB radio controlled clocks should be able to work in most places in North America. 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). For example, 0600 UTC is about midnight in the central United States.

0000 UTC

0200 UTC

0400 UTC

0600 UTC

0800 UTC

1000 UTC

1200 UTC

1400 UTC

1600 UTC

1800 UTC

2000 UTC

2200 UTC

These maps are based on a field strength of 100 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). However, simply having a large signal doesn't mean that the receiver will work. What really matters is the signal-to-noise ratio, or the size of the signal compared to the size of the electrical noise near the same frequency. Raising the noise level is just as harmful as reducing the signal level. For example, if the radio controlled clock is near a source of interference (like a computer monitor) the noise level will increase, and the clock might not be able to synchronize. If the radio controlled clock is in a building with a metal roof, much of the signal will be blocked. Therefore, the signal level will be reduced, and the clock might not be able to synchronize.

Therefore, use the coverage maps as a rough indicator only. We have heard from many owners of radio controlled clocks whose clocks do not work inside the coverage area shown on the maps. This is probably due to a local source of interference. We have also heard several reports from Alaska that the clocks work fine, even though Alaska is outside the coverage area shown on the maps. This is probably due to the low amount of radio “background” noise found in a sparsely populated area.

What to Do When They Don’t Work

NIST provides the signal received by your radio controlled clock, but we cannot provide technical support for the clocks themselves. We didn’t manufacture them, and we are not familiar with all the models or all of their features. We recommend that you save the instruction sheet that came with your clock, so you can refer to in the future if necessary. Having said that, we can offer a few general tips about what to do if your radio controlled clock isn’t displaying the correct time.

My clock doesn’t synchronize at all

Most WWVB radio controlled clocks work great, as evidenced by the hundreds of thousands of units that have been sold throughout the United States. However, if your radio clock or receiver isn't working, we suggest:

• If your clock uses batteries, check them and replace if necessary.
• If you have a desk top unit, try rotating it 90 degrees. If you have a wall clock try mounting it on a wall perpendicular to the one it is currently on (e.g. if it is on a north-south wall try an east-west wall). The antennas are directional and you might be able to improve the signal strength by turning the antenna.
• Place the clock along a wall or near a window that faces Fort Collins, Colorado.
• Locate the clock at least 1 or 2 meters away from any computer monitors, which can cause interference (some monitors have a scan frequency at or near the WWVB carrier frequency of 60 kHz).
• If nothing else works, take the clock outdoors at night and power it down (remove the batteries or unplug it), then power it up again to force it to look for the WWVB signal. If it works outdoors but not indoors, you probably have a local interference problem inside your house or building. If it doesn’t work outdoors at night, its probably best to return it and try a different model.
• The shielding provided by a metal building might prevent the clock from working. For example, if you live in a mobile home or a house with steel siding, the clock might not work.
• If you think your clock is defective, ask the manufacturer or dealer about obtaining a replacement.

My clock is off by one or more hours

Remember, minutes and seconds are the same in all time zones within the WWVB coverage area; only hours are different. If your clock is off by one or more hours, it probably has to do with a time zone setting. Make sure you have properly selected your time zone using the instructions that came with your radio controlled clock.

If you live in an area that does not observe Daylight Saving Time (Arizona, Hawaii, parts of Indiana), make sure that DST is disabled on your radio controlled clock. Not all clocks have this feature, so you might have to select another time zone to make your clock display the correct time when DST is in effect.

Some radio controlled clocks only allow you to select four different time zones (Pacific, Mountain, Central, and Eastern). Some clocks allow you to select any time zone, even those time zones that are outside the coverage area. When purchasing a clock, make sure that it can handle your time zone. For example, we’ve heard from a few users who purchased clocks in Hawaii but can’t select the Hawaiian Time Zone.

My clock is off by a few minutes or seconds

This can be due to a number of different problems as listed below:

Reception Problem - If your clock isn’t currently receiving the signal, the time will “drift” and gradually get further and further from the correct time. Remember, if the signal isn’t being received, your clock isn’t radio controlled any longer, it’s just a regular quartz clock. Its accuracy will depend on the quality of the quartz crystal. Most quartz clocks can keep time to 1 second per day or better, but some will be off by several seconds per day.

Most digital radio controlled clocks have an indicator on the display that tells you if the signal is being received properly. Some analog clocks have an audio indication (a button you can push that indicates through a series of tones or beeps if the signal is there). If you are not sure if the signal is being received, try powering down the clock (unplug it or remove the batteries), then turn it on again to see if it can synchronize. If it doesn’t, see the tips above for improving your reception.

Alignment Problem - If you have an analog clock, its possible that the hands aren’t properly aligned. This could cause the clock to be off by a second or more even if it is receiving the signal properly. The clock might not have been properly aligned at the factory, or it might have been jostled during shipment, causing the hands to move. Some manufacturers explain how to align the hands on their instruction sheet. If you aren’t sure how to do this, and the small error bothers you, it's best to return the clock.

Checking your clock - There is no need to check a properly working WWVB clock, it should always display the correct time. However, you might want to check it if you suspect you have a problem. You can check your clock by using the NIST web clock, or by listening to NIST Radio Station WWV using a shortwave radio or telephone (dial 303-499-7111).

When checking an analog clock, make sure you are looking straight at the clock face, and not viewing it from an angle. If you view if from an angle, you can think its off by a few seconds, even if its not. This is similar to trying to read the speedometer from the passenger seat of a car, and thinking the speed is faster or slower than it actually is.

We switched to Daylight Saving Time, and my clock didn’t change

This is probably due to a reception problem. Your clock hasn’t received the signal recently, so it didn’t know about the time change. Most digital radio controlled clocks have an indicator on the display that tells you if the signal is being received properly. Some analog clocks have an audio indication (a button you can push that indicates through a series of tones or beeps if the signal is there). If you are not sure if the signal is being received, try powering down the clock (unplug it or remove the batteries), then turn it on again to see if it can synchronize. If it doesn’t, see the tips above for improving your reception.

Also, some clocks have a way to disable Daylight Saving Time. Make sure it isn’t disabled if your area observes DST.

My clock switched to Daylight Saving Time, but we don't observe DST where I live

There is most likely an on/off toggle for DST. Turn it off if your area does not observe DST. Contact the manufacturer about how to do this. If there isn't a way to turn DST off, you may have to change your time zone setting during DST to make your clock display the correct time.

info from this page is courtesy of http://www.nist.gov/

Specifications:

• Time
  • 12/24 hour display in hh: mm ss format
  • Auto receive function
  • Manual receive function
  • Signal: US WWVB, Europe DCF77, Japan JJY40/JJY60
    
• Full Auto Calendar
  • Auto calculation of different month lengths (28, 30 or 31 days) and leap year 2000-2099
• Daily Alarm
• Stopwatch
  • Elapsed time, split time and final time are measured with 1/100-sec accuracy
• Counter Timer with Chime
  • Adjustable up to 23 Hr 59 Min 59 Sec
• Water Resistance
  • 3 ATM (100ft or 30m)
• Power
  • 1 CR1620 battery (included)
• Dimensions
  • Diameter of face: 1.75" (45mm)
  • Wrist size: approx. 6.1" - 8.5"(155mm - 215mm)

Maps showing ranges of the atomic time signal (click on images to enlarge)

Atomic Time Signal	Descriptions
	DCF77	Germany: transmitting from Mainflingen (near Frankfurt) at 77.5 kHz, with a range up to 2000 km, which covers most of Western, e.g. UK and some of Central Europe.
	JJY40/JJY60	Japan: transmitting from Mount Otakadoya (near Fukushima) at 40 kHz and 60 kHz, and from Mount Hagane (located on Kyushu Island) at 60 kHz, which together cover all of Japan and parts of Korea and East Asia e.g. Hong Kong, Beijing & Taiwan.
	WWVB	U.S.A.: transmitting from Fort Collins, Colorado, at 60 kHz, which covers all 4 zones in the continental U.S.A. and most places in North America.