La Crosse Technology WT-2191A - Manual (Page 7)

5
minutes of battery installation, you may
manually set the time or leave the time
function alone (reception will occur
regardless).
About Radio Controlled Time signal,
WWVB:
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 and date 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 alarm clock. However, due to the
nature of the Earth’s Ionosphere,
reception is very limited during daylight
hours. The alarm clock 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 is
continually measuring every second, of
every day, to an accuracy of ten billionths
of a second per day. These physicists