4. After power-up, the alarm will sound once and all LCD segments will light up briefly.
5. The clock will now start receiving the WWVB time signal and the radio tower icon will start
flashing indicating that time reception is being attempted
6. Time reception takes typically about 3-5 minutes with timeout being 10 minutes. If after 10
minutes the WWVB time signal has still not been received, the user should try one of the
following two actions:
Reset the unit by removing the battery and proceed from step 2 (above). Should after 10
minutes and the time is still not received the clock will automatically attempt to receive the
WWVB time signal two hours later.
Manually set the time (see
“Manual Time Setting”
below).
Note:
During the time of power-up (i.e. inserting the battery)
DO NOT
press any of the keys as
this will interrupt stop the WWVB time signal reception. If keys are pressed during this
stage, then proceed from
“Setting up the Atomic Alarm”
above.
If there is no WWVB signal then the radio tower will not appear on the LCD
When WWVB time reception is successful, the received time will automatically override
the manually set time and date. (Please see notes on
“Radio Controlled Time
Reception”
and
“Manual Time Setting”
).
WWVB icon (flashing)
Location test
sequence for better
reception
Radio controlled Time Reception:
During reception, the WWVB tower icon in the LCD will start flashing. This indicates that the
WWVB time signal is present and the clock is trying to receive it. At the same time, three digits
“000” will appear below the USA map in the LCD to indicate that the time data from the signal
source is being de-coding for the time. The digit on the left should randomly display the
numbers 0, 1 or 8 for a strong signal. If 0, 1 or 8 are not displayed, then reposition the clock for
a better signal.
When the time signal is received, the WWVB tower becomes permanently lit and the time will
be displayed.
General Information on WWVB radio controlled time
NIST Radio Station WWVB is located on the WWVB site near Ft. Collins, Colorado. The
WWVB time code is transmitted by the 60 kHz carrier and is broadcast continuously at a rate of
1 pulse per second using pulse width modulation.
The broadcast information includes the year; time intervals; Daylight Saving Time and leap
year. The accuracy of the transmitted WWVB signal is better than 1 part in 100 billion (1 x 100
-
11
) and with day to day deviations being less than 5 parts in 1000 billion
(5 x 10
-12
).
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