La Crosse Technology WIRELESS WEATHER STATION Instruction Manual page 35

In area where reception of the DCF-77 time is not possible, the DCF-77 time
reception function can be turned OFF. The clock will then work as a normal Quartz
clock. (Default setting is ON).
1. The digit "ON" and the time reception icon will start flashing on the LCD.
2. Use the + key to turn OFF the time reception function.
3. Confirm with the SET key and enter the "12/24-Hour Display setting" or
exit the setting mode by pressing the CH key.
Note:
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