La Crosse Technology WS-8010U - Manual (Page 10)

10
FEATURES
I. ABOUT WWVB (Radio Controlled Time)
The NIST (National Institute of Standards and Technology—Time and
Frequency Division) WWVB radio station is located in FT. Collins, Colorado,
and transmits the exact time signal continuously throughout the United States at
60 kHz. The signal can be received from up to 2,000 miles away through the
internal antenna in the Weather Center. However, due to the nature of the Earth’s
Ionosphere, reception is very limited during daylight hours. The Weather Center
will search for a signal every night, when reception is best. The WWVB radio
station derives its signal from the NIST Atomic clock in Boulder, Colorado. A
team of atomic physicists continually measure every second, or every day, to an
accuracy of ten billionths of a second a day, creating an international standard,
measuring a second as 9,192,631,770 vibrations of a Cesium-133 atom in a
vacuum. This Weather Center regulates the WWVB sensor.
II. WEATHER FORECAST
The weather forecasting feature is estimated to be 75% accurate, basing the
weather forecast solely upon the change of air-pressure over time. The
WS-8010U averages past air-pressure readings to provide an accurate forecast—
creating a necessity to disregard all weather forecasting for 12-24 hours after the
Weather Center has been set-up, reset, or moved from one altitude to another (i.e.
from one floor of a building to another floor).
A. WEATHER ICONS
There are 3 possible weather icons that will be displayed in the FORECAST
DISPLAY:
Sunny—indicates that the weather is expected to improve (not that the weather
will be sunny).
Sun with Clouds—indicates that the weather is expected to be fair (not that the
weather will be sunny with clouds).
Clouds with Rain—indicates that the weather is expected to get worse (not that
the weather will be rainy).
The weather icons change when the unit detects a change in air pressure. The
icons change in order, from “sunny” to “sun with clouds” to “clouds with rain,”
or the reverse. It will not change from “sunny” directly to “clouds with rain,”