La Crosse Technology WS-9031U - Manual (Page 16)

3. Adjust the projection image in an upright position with the key.
Note:
If more than one Thermo-hygro Sensor is used, only the temperature from
sensor 1 will be projected.
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 up to 2,000 miles away through the
internal antenna in the Weather Projection Station. However, due to the nature
of the Earth’s Ionosphere, reception is very limited during daylight hours. The
Weather Projection Station will search for a signal every night when reception
is best.
The WWVB radio station receives the time data 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. For more
detail, visit http://www.boulder.nist.gov/timefreq.htm. To listen to the NIST
time, call (303)499-7111. This number will connect you to an automated time,