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In many regions, conventional time signals like WWV are not available continuously; on the other hand the signals of the Omega navigational system can be received everywhere 24 hours a day. They are not, strictly speaking, time signals, but they can be used to synchronize clocks to an accuracy of about 0.01 s. The Observatory of Neuchâtel, Switzerland, has developed such a clock; it is battery operated (5 years autonomy), small (14×13×4 cm), light (400 g, including antenna and battery), and fixed-tuned to one particular Omega transmitter.

There are eight Omega stations evenly distributed around the earth, and no land area is further away than 5000 km from the nearest transmitter. For a distance of this order the clock described above has been measured to have an accuracy of better than 0.01 s in the temperature range 0°C to +40°C. The clock is actually driven by a quartz crystal, and the synchronization with the Omega signals is achieved in small steps of about 0.5 ms every 10 s. During times of poor reception, caused by local thunderstorms, the clock continues to run with the accuracy of its quartz crystal. The clock should prove useful for many geophysical applications and can be purchased in sample quantities. For detailed information write to Otfeervatoire Cantonal, Neuchâtel, Switzerland.