In case you don't already know.  Atomic watches have tiny radio receivers inside and they periodically synchronize with a signal broadcast from a location with an atomic clock.  Here in the US, the atomic clock signal originates from Fort Collins Colorado.  There are also atomic clock radio transmitters located in Japan, the United Kingdom, and in Europe (Germany). 

Each transmitter broadcasts on a unique radio frequency and many atomic watches only work with a single transmitter (or in a single country).  For example most Casio WV57xxx models are US-only, where the Casio WVA510xxx models work in both the US and in Japan.

The Timex models I've seen so far (T 5E881 and T 5G341) adjust for any of the currently available transmitters based on which time zone you set the watch for.

Here are my Ownership Tips

1. My Top Atomic Watch Tip - Maybe once a week, leave your Atomic Watch overnight near a window.  You'll probably understand why after reading the rest of these tips.
   
2. Note the signal reception cycle - Each watch is pre-programmed to check the time synchronization radio signal 3-4 times per day.  And because the antenna in the watch is so small and the signals are easiest to receive at night, Atomic Watches typically do their magic between midnight and 5 AM.
   
3. Check signal indicator in the mornings - This lets you know if you are keeping the watch in a location where it can read the radio signal on a reliable basis. If it misses the signal, try again with the watch rotated 90-degrees from how you placed it last time.
   
4. Daylight Saving Time - If your Atomic Watch is kept in a location with somewhat weak signal reception, it can cause it to miss DST being turned on or off.  This creates a 1-hour difference and is best corrected by following Tip #1 (leave the watch near a window overnight).
   
5. Solar charging - If you have a Atomic Watch that uses the Solar-charged batteries, it will go into Power Save mode if kept in the dark.  Power Save mode may cause Analog hands to stop moving until the watch is exposed to bright light.
   
6. Changes cause loss of signal indicator - This is normal behavior.  If you adjust the watch because you have changed time zones, the radio signal indicator typically goes blank until the next synch cycle.
   
7. Manual receive - You can force the watch to look for the synchronization radio signal and update itself.  If you do this, I have two recommendations.  First plan on setting the watch on a window sill and leave it alone for 5 minutes immediately after triggering the manual receive.  Second, you'll have a greater chance of success if you do this at night when the signal is strongest.
   
8. Know where Colorado is - If you are in the US, having the watch near a window that faces in the general direction of Colorado will help since that is where the signal is broadcast from.

Can you get atomic time without an atomic watch? 

Sure, there are several sources:

1. Telephone - (303) 499-7111 (Colorado) and  (808) 335-4363 (Hawaii)
   
2. Internet – The National Institute of Standards and Technology - See my Blog Entry for the Link
   
3. GPS Units – The Global Positioning System relies on calculations based on distance from satellites broadcasting a signal pattern based on the atomic time.  So most GPS units have  a clock feature that stays relatively accurate because of how it utilizes the satellite signals.  However the GPS manufacturers will tell you the clock can be off by a couple of seconds because they put a priority on displaying accurate location data (time information is secondary).

Brief Commercial plug - I do sell Casio and Timex atomic watches, so please check out my Sun-Bits eBay Store if you are interested.

Yes, I am tickled when I see when someone has given my guide a "Helpful" vote.  But either way, thank you for taking the time to read this Guide.

This guide and photos copyright 2006 Sun-Bits