This Porthole clock combines the best of both worlds; the modern-day electronics of the Radio Control Clock with the traditional beauty of a solid brass porthole and mahogany finished frame. All brass is hand polished and lacquered for long-lasting enjoyment. It is beautiful yet extremely accurate.
To setup, insert an AA battery, select your time zone with the clearly marked knob, and then hang it on the wall. The clock will automatically set itself to the exact time.
Each instrument is provided with complete instructions, mounting hardware, lifetime warranty, and a fresh battery.
Wt. 3 lbs. 15 oz.
Dial: 6-1/8", Base: 9-7/8", Depth: 3".
Radio Control Clocks Nothing is measured more precisely than time!
Since the beginning of time, man has been fascinated with the measurement of time and has devised more accurate machines to trap and measure time. Today, time is precisely controlled in the United States by the most accurate clock in North America, the atomic clock of the US National Institute of Standards and Technology, Time and Frequency Division in Boulder, Colorado.
A Team of atomic physicists continually measures every second of every day to an accuracy of ten billionths of a second per day. These physicists have created an international standard, measuring a second as 9,192,631,770 vibrations of a cesium 133 atom in a vacuum. This atomic clock regulates the WWVB radio transmitter located in Fort Collins, Colorado, where the exact time signal is continuously broadcast throughout the United States at 60 kHz to take advantage of stable longwave radio paths found in that frequency range. Radio waves at these low frequencies use the earth and the ionosphere as a wave-guide and follow the curvature of the earth for long distances.
The built-in antenna system will receive the WWVB signal anywhere in North America where long-wave reception is undisturbed. A microprocessor activates the receiver and process the time signal from Fort Collins overnight. Even adjustment for daylight savings time, and leap second are automatic.