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Radio Stations |
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Services |
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Standards |
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Time Transfer |
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Metrology |
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Research |
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Data |
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Frequently asked questions (FAQ) index
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Here are some frequently asked time and frequency questions grouped by category. If you have a question, look for an answer here. We'll add new questions to this list as we receive them.
Precision
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The current time, precision methods, Global Positioning System (GPS), and atomic clocks.
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Leaps
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Leap years and leap seconds.
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History
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General history, hours, minutes, & seconds, Daylight Saving Time (DST), and time zones.
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Government
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National and international timekeeping, Greenwich Mean Time (GMT), and time zone law. |
Broadcast |
Time signals broadcast by radio, telephone, and Internet. |
Misc |
Coordinated Universal Time (UTC), a.m./p.m., Modified Julian Date (MJD), and other related questions. |
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