A radio clock is controlled by a radio transmitter that synchronizes the time with a precise time keeper like an atomic clock. A radio-controlled clock is your best choice if you want the most exact timepiece.

Although a radio-controlled clock can be manually set, the adjustments made by receiving radio messages keep it operating smoothly and in time with a more precise atomic clock. A radio clock is more than simply a timer that adds seconds and minutes to the time you specify; it's…