REPOST: It’s about Time – NIST WWV Radio Reference Signals

This is a repost of a February 2007 Article. Several of our local club members asked about WWV during a club shack session, prompting the return of this article.
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Did you know that the USA Government provides a free to use time reference that is as accurate as anything on the planet?

Perhaps you have heard the “beep beep beep at the Tone it is X:XX Universal Coordinate Time” on the air?

Perhaps you have an “Atomic Clock” or watch?

Perhaps you have even done sound-calibrations using the WWV radio signal and one of the digital mode software packages?

All use the WWV (and WWVH & WWVB) radio transmissions.

The National Institute of Standards and Technology is the US Government Agency charged with running the radio time beacons as part of its overall charter:

NIST’s mission is to promote U.S. innovation and industrial competitiveness by advancing measurement science, standards, and technology in ways that enhance economic security and improve our quality of life.

NIST Radio Station WWV is the part of NIST that Radio Amateurs most use.

Located in Colorado, the site itself is not open to the public, and looks like this:

MIST WWV Transmitter Station

How accurate is WWV’s time keeping?

Less than 1 microsecond of Coordinated Universal Time (UTC) at the transmitter.

Of course the signal is delayed as it travels to your receiver.

This delay increases with distance, and also changes with Propagation as at various times the signal is bouncing between the earth and the ionosphere which effectively changes the distance. Usually in the USA the accuracy should be better than 10 milliseconds (1/100 of a second).

Over the telephone, acurracy drops, but WWV should still be accurate to less than 40 milliseconds (1/25 of a second).

The Broadcast Format

Is best explained by this NIST WWV Graphic:

NIST WWV Broadcast Format Chart

WWV broadcasts much more than just the time. There is so much it is best to simply check the WWV Website for more information!

The Phone Option

WWV shortwave broadcast, can be heard by phone at (303) 499-7111 and for WWVH time announcements from Hawaii, call (808) 335-4363 WWVB does not have a number published

The Internet Option

You can synchronize your computer clock to NIST using either an Internet or a dial-up, and using simple software available at the WWV site.

Other Uses

Using WWV to calibrate radios or other gear is quite easy, but usually equipment specific. You will need to follow the directions for your specific gear.

WWV is a unique service. Though a few other countries have similar systems, no other has so much to offer on an open user basis.

Remember “It’s about Time” at WWV !!!

73

Steve
K9ZW

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