La Crosse WS-8249U Instruction Manual - page 12
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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
measures every second of every day to an accuracy of ten billionths of a second a 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. This atomic clock regulates the WWVB transmitter.
Once the outdoor temperature is displayed on the atomic clock, the WWVB tower icon in the
clock display will start flashing in the top center of the LCD. This indicates that the clock has
detected a radio signal and is trying to receive it. When the time code is received, the WWVB
tower becomes permanently lit and the time will be displayed.
If the tower icon flashes, but does not set the time or the WWVB tower does not appear at all,
then please take note of the following:
•
Recommended distance to any interfering sources like computer monitors or TV sets is a
minimum of 6 feet (2 meters).
•
Within ferro-concrete rooms (basements, superstructures), the received signal is naturally
weakened. In extreme cases, please place the unit close to a window and/ or point its front or
back towards the Fort Collins, Colorado, transmitter.
•
During nighttime, the atmospheric disturbances are usually less severe and reception is
possible in most cases. A single daily reception is adequate to keep the accuracy deviation
below 1 second.
Note:
In case the atomic clock is not able to detect the WWVB-signal (disturbances, transmitting
distance, etc.), the time can be manually set (please refer to notes on
Manual time setting
).
WEATHER FORECAST
The weather forecasting feature is estimated to be 75% accurate. The weather forecast is based
solely upon the change of air pressure over time. The WS-8249U averages past air-pressure
readings to provide an accurate forecast, creating a necessity to disregard all weather forecasting
for 12-24 hours after the unit has been set-up, reset, or moved from one altitude to another (i.e.
from one floor of a building to another floor). In areas where the weather is not affected by the
change of air pressure, this feature will be less accurate.