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Keeping Time with NTP and a WWVB Radio Receiver - Page 1 |
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Almost everything in todays PC's relates in some way to time: CPU cycles, bus frequencies, graphics refresh rates, file dates, even a simple cursor blink. Correct time is one of the fundamentals for reliable and secure computing. Yet setting and keeping correct time is one of the challenges standard computers didn't solve yet. Computer time happily drifts away and relies on the user to be set, while any cheap digital watch keeps better time and is often already radio synchronized to a public time service. |
 UltraLink Model 325 WWVB Time Receiver, serial port |
Wouldn't it be good to have such a root server directly in your local network? There are several ways to do that. Apart from turnkey blackbox networked server solutions ($$$), a time signal receiver can be attached to a soon to be NTP root server (off the shelf hardware), usually through a parallel or serial port. Several receiver technologies are to choose from, with GPS the most expensive. For my budget and requirements, I choose the M325 WWVB radio receiver from UltraLink. Moderate priced at $165, it is small, compact and, something I learned to value highly, does not need an external power supply. The receiver gets its time signal from the atomic clock in Fort Collins, Colorado, operated by the |
National Institute of Standards and Technology (NIST). The signal is transmitted in low frequency at 60kHz with an effective power of 50KW and an accuracy of up to 100 microseconds. It covers all States in the U.S., with the exception of Alaska and Hawaii. Hawaii got its own WWV station located on the island of Kauai near Kekaha, while Alaska is covered by the Canadian time signal. |
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