A La Crosse Atomic Wall Clock is a radio-controlled wall clock. This means that the clock uses long-wave radio signals to set the time itself, based on the time zone you chose for the clock. The clock then automatically resets the time as needed, such as if the clock is lagging behind or during daylight savings time.
Slide the battery cover on the back of the clock downward. Insert a AA battery into the housing unit and slide the battery cover back over the battery housing unit.
Press the "PT" (Pacific Time), "MT" (Mountain Time), "CT" (Central Time) or "ET" (Eastern Time) button for the time zone in which you are located. If you press more than one button, the clock will display the time based on the button you last pressed. If no button is pressed, the clock will set to Pacific Time.
Place the clock upright in front of a window. The clock will search for a signal. Due to the nature of long wave radio signals, a signal may not be available in the day and may need to stay in the window overnight. The clock will continue searching for a signal until it receives one. Once the time has been set, the clock can be hung on a wall.