La Crosse Technology WS-7391UF Wireless 433 MHz Weather Station with Atomic Clock, (AKA Lacrosse Technologies WS7391UF)

La Crosse Technology WS-7391UF Wireless 433 MHz
Weather Station with Atomic Clock

For definitions of the feature icons, please click any icon.

The La Crosse Technology WS7391UF displays indoor and outdoor temperature plus indoor and outdoor relative humidity. It also has a moon-phase display with tide indication, a weather-forecasting feature with three indicator icons, and an integral atomic clock. Outdoor temperature and humidity are transmitted to the station via the included TX4U remote sensor. The station can actually receive signals from a total of three remote transmitters (additional transmitters are optional and sold separately).

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Styled as a black bulb-type thermometer in a real wood case with a rich mahogany finish, the wall-mount WS7391UF has plenty of convenient features, including an atomic clock. In addition to day/date/time and moon phase with tide indication, the station displays indoor temperature and humidity, outdoor temperature and humidity (via an included remote transmitter), forecasting information, and indoor comfort level. Install one or two optional remote transmitters, and get outdoor temperature and humidity data from additional locations.

The station's incredibly accurate radio-controlled atomic clock features day, date, and time displays. Time can be displayed as 12-hour or 24-hour, and the clock can be optioned to automatically adjust for daylight saving time.

Almost 18 inches tall and over 6 inches wide, the station is black (with silver function buttons) in a mahogany-finished wood case and is intended for wall mounting only. Its LCD displays are large for easy reading, and the LCD display contrast can be adjusted for any of 8 different levels.

The station's weather-forecasting feature senses barometric pressure over time and adjusts the indicator icons to provide accurate forecasts based on pressure trends. Another clever feature of the WS7391UF is an indoor comfort level indicator with happy and sad face icons.

The station keeps a record of the minimum and maximum indoor and outdoor temperatures and humidity it has recorded, and these are available at the push of a button.

Not only will the station operate with up to three remote transmitters, three different transmitters are available. The TX3U reports outdoor temperature only and has an LCD display for local viewing. The TX4U (the one included with the station) reports both outdoor temperature and humidity. The TX3UP senses temperature via a probe on a 10-foot (3m) wire for use in pools, spas, soil, etc., and has an LCD display like the TX3U.

The station's clock calibrates itself to the world's most accurate clock every night by receiving WWVB radio transmissions. These transmissions contain time information from the U.S. atomic clock source, operated by the U.S. Commerce Department near Boulder, Colorado. The built-in antenna ensures reliable signal reception up to 2000 miles (3200km) from the WWVB transmitter.

Substantial in size with elegant styling and many convenient features, the WS7391UF is ideal for larger rooms and offices. If you would prefer this same station in a different color or finish, please check out the following:

WS7391U(D): Real wood case with warm cherry finish and black "thermometer" display. Function buttons ("bulb" portion of display) are dark gray.
WS7391U(G): Real wood case with handsome natural finish and and black "thermometer" display. Function buttons ("bulb" portion of display) are dark gray. (Note from lacrossetechnology-at-psmall.com: The finish of the wood case is a medium brown and not as "blond" as some pictures of the station indicate.)
WS7390U: Black plastic case with silver "thermometer" display. Function buttons ("bulb" portion of display) are silver.

Features:

Clock sets automatically to WWVB radio signal (manual setting is also possible)
12/24-hour time display (hour, minute, second)
Date (calendar) display
Moon phase display with tide indication
Station displays indoor and outdoor temperature and relative humidity with minimum and maximum recordings and time and date of recording (resettable)
Temperature indication selectable for either °F or °C
Three weather-forecasting icons
Weather tendency indicators
Indoor comfort level indicator with happy and sad face icons
One outdoor temperature and humidity transmitter included; additional transmitters are optional and sold separately
Can receive and display information from up to three outdoor transmitters
LCD display contrast selectable for 8 different levels
Station powered by two AA alkaline batteries (not included), with average life of about 1 year
Remote transmitter (TX4U) powered by two AA alkaline batteries (not included), with average life of about 1 year

Station Specifications:

Radio-controlled time signal: WWVB
Recommended operating temperature:
32° to 122°F ((0° to 50°C)
Indoor temperature measuring range:
32° to 140°F with 0.2°F resolution
(0° to 60°C with 0.1°C resolution)
Outdoor temperature measuring range:
-21.8° to 139.8°F with 0.2°F resolution
(-29.9° to 59.9°C with 0.1°C resolution)
Indoor and outdoor relative humidity range:
20% to 95% with 1% resolution
Indoor checking intervals:
Indoor temperature: every 20 seconds
Indoor relative humidity: every 1 minute
Outdoor checking intervals:
Outdoor temperature: every 5 minutes
Outdoor relative humidity: every 5 minutes
Transmitter temperature reading update: 1 minute
Station dimensions:
6.41 inches (16.3cm) wide
17.71 inches (45.0cm) high
1.22 inches (3.1cm) deep

Remote Thermo-Hygro Transmitter (TX4U) Specifications:

Remote transmission of outdoor temperature and humidity to station via 433 MHz signals
Recommended operating temperature:
-25° to 158°F (-31.6° to 70.0°C)
Temperature measuring range:
-21.8° to 156.2°F with 0.2°F resolution
(-29.9° to 59.9°C with 0.1°C resolution)
Relative humidity range:
20% to 95% with 1% resolution
Checking intervals:
Temperature: every 5 minutes
Relative humidity: every 5 minutes
Transmission interval: every 10 seconds for first 3 minutes, every 1 minute thereafter
Transmission frequency: 433.92 MHz
Transmission range: 80 feet (25m) in open space with no interference
Wall mounting
Power source: two AA (1.5V) alkaline batteries (not included)
Remote transmitter dimensions:
1.6 inches (4.0cm) wide
4.3 inches (11.0cm) high
0.8 inch (2.0cm) deep (not including mounting bracket)
Rain protector dimensions:
2.24 inches (5.7cm) in diameter
4.7 inches (12cm) high
Remote transmitter dimensions with rain protector installed and including mounting bracket:
2.24 inches (5.7cm) wide
4.88 inches (12.4cm) high
2.87 inches (7.3cm) deep

Radio-controlled Time:

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 Integral Atomic Clock:

The atomic clock integral to the WS7091UF 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 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 batteries, wait until the signal is received, and program the desired additional settings. In locations outside of WWVB range, the 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 atomic 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 between midnight and 6:00 a.m. 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 saving 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.