radio-synched clock : Computer Hardware Buyers’ Glossary

1. It should be very accurate.
2. You might want it to display 24-hour time.
3. It should automatically and accurately correct for daylight saving time so you can verify your computer and other equipment and clocks are correctly set.

Radio-Synched Accurate Clocks

Because of anomalies such as the fact Illinois ignores DST, the clocks are not always 100% automatic. You have to tell them the time zone, and sometimes you must tell them the approximate time. Here is a typical fudge to deal with the fact Illinois ignores DST.

The signal from Colorado includes a bit to say whether DST is currently in effect. The Colorado signal does not contain information about DST for different geographical regions that don’t follow the US federal pattern. This means clocks can handle the national days of switchover being changed but cannot automatically handle regions differing from the national standard.

The clocks work all through the USA and southern Canada, though you need good radio reception. You might want to borrow a clock to test the reception in the room you plan to keep it. You might get great reception on the Colorado side of your building outside, but hopeless reception inside.

Manufacturers call them analog atomic clocks and digital atomic clocks, though there is nothing radioactive in them. They are merely radio-synchronised from a government atomic clock.

When I was a child a read a story about a man who devised a scheme to keep all the world’s clocks in sync. People thought him mad. Today you have to be mad to put up with an inaccurate clock or one that keeps forgetting its time every time it loses AC (Alternating Current) power or its batteries run down.

Vendors of Radio-Synched Clocks

•  WeatherBuffs.com atomic analog, digital, mantel clocks and watches
• Weather Connection atomic analog wall clocks atomic digital wall clocks atomic alarm clocks atomic watches
• The Clock Depot
• Radioworld Canada. Mostly small travel clocks.
• BRG Canada. Commercial clocks. Ethernet synched clocks. Building-synched clocks.

Desk and Wall Radio-Synched Clock Models

Wall Clocks
Model	Cost CurrCon Applet needs Java 1.5 or later to display prices in your local currency. CurrCon Applet needs Java 1.5 or later to display prices in your local currency.	Appearance	Notes
Oregon Scientific Atomic Digital Desk Clock	$29.00 CAD		MRM-983A. This exact model is no longer manufactured, but there are several other models similar to it. Keeps accurate time by monitoring a radio signal from a US government atomic clock in Colorado. It also displays room temperature in Fahrenheit only. 12 or 24 hour digital display.8.76 × 11.43 cm (3.45 × 4½ in). I have one on my desk. It is not smart enough to automatically adjust for DST. It is very simple to use since other than setting the time and date to get it started, it stays in synch automatically. It has two alarms: The weekday alarm that goes off each day that goes off only on Monday through Friday. The single alarm that goes off each day By tapping the  button you can cycle between time with seconds, time with day of week and UTC-offset (-8 for PST (Pacific Standard Time) and -7 for PDT (Pacific Daylight Time)). You must manually enter the date and time to let it know the offset from UTC (Coordinated Universal Time/Temps Universel Coordonné), and from then on it stays in sync. It has one serious design flaw. It is fairly easy to inadvertly turn off the clock’s ability to receive radio signals. Idiotically, the clock goes to a default mode after you change the batteries where it ignores the synching broadcasts. You turn it back on by pressing and holding the up arrow ▲ to enable radio synching. You should see an animated radio tower if synching is turned on. You can figure out the buttons without the manual if you know that you press once to select the W alarm (or twice to select the S alarm) then press and hold  for two seconds to enter alarm setting mode. E means English day of week abbreviations. You turn the alarms on and off with the arrows. The presence of the bell icon does not mean the alarm is turned on. The instructions come in microscopic type.
Honeywell Atomic Digital Wall Clock	$40.00 USD		Model RCW33W. Keeps accurate time by monitoring a radio signal from a US government atomic clock in Colorado. It also displays temperature inside and out using an included remote sensor. 12 or 24 hour digital display. 28.58 × 17.14 cm (11¼ × 6¾ in)
Lacrosse Atomic Analog Wood Wall Clock	$23.00 USD		Model WT-3122J. Wood. Keeps accurate time by monitoring a radio signal from a US government atomic clock in Colorado. 12 hour analogy display. No temperature display. 30.48 cm (12 in) diameter.
Lacrosse Atomic Digital Wall Clock	$45.00 USD		La Crosse WS-8117C-IT Weather Station Wall Clock. Keeps accurate time by monitoring a radio signal from a US government atomic clock in Colorado. It also displays temperature inside and out using an included remote sensor. 12 or 24 hour digital display. It also computes the phase of the moon. 20.32 × 30.99 cm (8 × 12.20 in)
Lacrosse Atomic Plastic Analog Wall Clock	$25.00 USD		La Crosse WT-3144P. Plastic. Keeps accurate time by monitoring a radio signal from a US government atomic clock in Colorado. 12 hour analogy display. No temperature display. 35.56 cm (14 in) diameter.