The WS8248U-CH has four user-selectable display modes. Information shown in the initial display mode (pictured) includes hour and minutes, month and date, weekday, indoor temperature, indoor relative humidity, outdoor temperature, and moon phase. The three other display modes let you display clock seconds digitally in place of indoor humidity, indoor temperature, or outdoor temperature. A tower and waves icon appears in the upper left corner of the top (hour and minutes) section of the LCD panel to indicate successful reception of the atomic clock time-synchronization radio signal.

In addition to large displays, this clock's LCD panel has 8 user-selectable contrast levels for optimum viewing under a variety of lighting conditions.

The moon phase icon on the WS8248U-CH shows 12 different phases, not the 8 phases of some smaller moon phase clocks. Please be aware that dark portions of the icon represent the illuminated area of the moon.

There's one more thing you'll really appreciate on this clock. It's the location of the four control pushbuttons. They're right on the front, just below the lower display section. You won't have to take this clock off of the wall or turn it around to change a display parameter or the display mode, set the alarm, or activate the snooze function when the alarm sounds.

When you set the alarm time, it appears in the lower section of the LCD panel where the indoor temperature and humidity are shown in the initial display mode during normal operation. The alarm is automatically switched on when the alarm time is set, and the alarm-on state is indicated by an alarm icon between the moon phase and the calendar month. After the alarm time is set, you can turn the alarm on or off during normal operation by pressing the ALM (alarm) button. 

We should mention that the outdoor temperature is transmitted to the clock by an included TX6U wireless remote thermo sensor/transmitter. Maximum transmission range in open areas is 330 feet (100 meters) when the TX6U is used with the WS8248U-CH.

Please have a look at the Features list below. We're genuinely impressed with the WS8248U-CH atomic clock, and we think you will be, too.

Note: As is typical of giant-display digital LCD clocks, this one does not have a backlight for its displays.

Features:

• Sets automatically to WWVB (60 kHz) radio signal from U.S. atomic clock in Colorado. Manual setting is also possible.
• Radio tower and waves icon indicates WWVB signal reception.
• Giant time display in 12-hour format:
  • Hour and minutes digits are 4 inches tall and separated by a flashing colon (:) that indicates seconds.
  • PM is displayed along with time when appropriate.
• Hour, minutes, month, date, and weekday are continuously displayed.
• Four user-selectable display modes let you display digital seconds in place of indoor humidity, indoor temperature, or outdoor temperature.
• Any of 13 time zones can be set. Select Greenwich Mean Time (GMT) or -1 to -12 hours.
• Time zones from -4 to -10 hours and GMT (0) are displayed with 3-letter abbreviations: ATL (Atlantic), EST (Eastern, the default setting), CST (Central), MST (Mountain), PAC (Pacific), ALA (Alaska), HAW (Hawaii), and GMT.
• Daylight Saving Time (DST) on/off option.
• Full auto-calendar for year 2003 to 2039 (default setting is 2004).
• Three-letter month and weekday abbreviations are user-selectable for any of 3 languages: English, French, or Spanish.
• One daily alarm. Pressing SNZ (snooze) button suspends alarm for 10 minutes.
• Alarm time can be displayed in the lower section of the display.
• Temperature displays are user-selectable for °F or °C.
• Moon phase icon shows 12 different phases.
• LCD panel contrast is user-adjustable for 8 levels for optimum viewing.
• Maximum transmission range for remote temperature is 330 feet (100 meters).
• Clock can be wall mounted, or integral foldout props can be extended for placement on a table or shelf.
• TX6U remote transmitter is wall mounted via an included bracket into which transmitter snaps.
• Clock is powered by three AA (1.5V) alkaline batteries (not included), with normal life of up to 18 months.
• TX6U is powered by two AA (1.5V) alkaline batteries (not included), with normal life of about 1 year. For use in sub-freezing temperatures, AA lithium batteries are recommended instead of alkaline.

WS8248U-CH Clock Specifications:

• Time source and frequency: WWVB, 60 kHz
• Indoor temperature measuring range:
  +14.1°F to +99.8°F with 0.2°F resolution
  -9.9°C to +37.6°C with 0.1°C resolution
  ("OFL" is displayed if outside this range)
• Outdoor temperature measuring range:
  -21.8° to 157.8°F with 0.2°F resolution
  -29.9°C to +69.9°C with 0.1°C resolution
  ("OFL" is displayed if outside this range)
• Temperature checking interval:
  • Indoor: every 10 seconds
  • Outdoor: every 5 minutes
• Indoor humidity measuring range: 1% to 99% relative humidity
• Dimensions:
  12 inches (305 mm) wide
  11.75 inches (299 mm) high
  1.25 inches (32 mm) deep

• Remote transmission of outdoor temperature to station via 433.92 MHz signals
• Temperature checking interval: every 1 minute, with reception by WS8248-OAK clock every 5 minutes
• Water-resistant case
• Wall mounting (remote unit snaps into its own wall-mounted bracket)
• Dimensions:
  1.57 inches (40 mm) wide
  5.04 inches (128 mm) high
  0.9 inch (23 mm) deep

The NIST (National Institute of Standards and Technology, Time and Frequency Division) maintains a radio station, WWVB, in Ft. Collins, Colorado. The WWVB radio station derives its signal from the NIST atomic clock in Boulder, Colorado. A team of atomic physicists is continually measuring every second of every day, to an accuracy of ten billionths of a second per day. These physicists have created an international standard, measuring a second as 9,192,631,770 vibrations of a Cesium-133 atom in a vacuum.

WWVB (the station’s identification just like any other radio station) continuously broadcasts time and frequency signals at 60 kHz. The carrier frequency provides a stable frequency reference traceable to the national standard. There are no voice announcements on the station, but a time code is synchronized with the 60 kHz carrier and is broadcast continuously at a rate of 1 bit per second using pulse width modulation. The time code contains the year, day of year, hour, minute, second, and flags that indicate the status of Daylight Saving Time, leap years, and leap seconds.

The La Crosse Technology WS8248U-CH Radio Controlled Digital Clock:

The La Crosse Technology Radio Controlled Digital Clock maintains its incredible accuracy by automatically tuning into the WWVB radio signal. The built-in antenna ensures reliable signal reception up to 2000 miles (3200km) from the WWVB transmitter. As a result, the La Crosse Technology clock will calibrate to the atomic clock not only throughout the mainland U.S. but also in much of Canada. You need only insert the battery, wait until the signal is received, and program the desired additional settings. In locations outside of WWVB range, the La Crosse clock can be manually set and will provide the high degree of accuracy of any quality quartz clock.

In a nutshell, here's how the the La Crosse clock works: The clock's antenna is specifically tuned for optimal reception of the 60 kHz time signal. The time signal received on the antenna is demodulated by an onboard receiver, which sends the information to the clock's CMOS microprocessor for decoding. Once your clock has automatically set its time for the first time, it ensures continuing accuracy by automatically tuning into the WWVB radio signal once per day at midnight. (If no signal is detected, the clock performs its WWVB check hourly until the signal is found.) As long as your clock is kept within transmitter range, it will continue to display the absolutely precise time, automatically adjusting for summer time/winter time changeovers if the daylight savings time option is ON. Should you move your clock out of transmitter range for an extended period of time, the clock will continue to operate as a highly accurate quartz-controlled clock. Upon re-entering the transmitter range, your clock will correct itself again to the precise WWVB time signal.