Casio 3476 Owner's Manual page 24

About the Receiving Indicator
The receiving indicator shows the strength of the calibration signal being received.
For best reception, be sure to keep the watch in a location where signal strength is
strongest.
Receiving indicator
• Even in an area where signal strength is strong, it takes about 10 seconds for signal
reception to stabilize enough for the receiving indicator to indicate signal strength.
• Use the receiving indicator as a guide for checking signal strength and for finding
the best location for the watch during signal receive operations.
EN-22
Weak
(Level 0)
Strong
(Level 3)