[Fwd: LF: info rgd WWVB]

[Andre' Kesteloot]

Soegiono, Gamal wrote:

> Hello all,
>
> on my search about LF stations found the following:
>
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> http://www.boulder.nist.gov/timefreq/wwvstatus.htm
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> NIST Radio Station WWVB
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> NIST Radio station WWVB is located on the WWV site near Ft. Collins,
> Colorado.
> The WWVB broadcasts are used by millions of people throughout the United
> States
> to synchronize consumer electronic products like wall clocks, clock radios,
> and
> wristwatches. In addition, WWVB is widely used for high level applications
> such
> as network time synchronization and frequency calibrations.
>
> WWVB continuously broadcasts time and frequency signals at 60 kHz. WWVB does
> not
> broadcast voice announcements, but provides standard time information,
> including
> the year; time intervals; Daylight Saving Time, leap second, and leap-year
> indicators; and UT1 corrections by means of a BCD time code. In addition,
> the
> 60-kHz carrier frequency provides an accurate frequency standard which is
> referenced
> to the NIST Frequency Standard.
>
> The transmitted accuracy of WWVB is normally better than 1 part in 100
> billion
> (1 x 10-11). Day-to-day deviations are less than 5 parts in 1000 billion
> (5 x 10-12). The BCD time code can be received and used with an accuracy of
> approximately 0.1 ms. Propagation effects are minor compared to those of WWV
>
> and WWVH. When proper receiving and averaging techniques are used, the
> received
> accuracy of WWVB should be nearly as good as the transmitted accuracy.
>
> NIST Radio Station WWVB is currently undergoing major equipment upgrades.
> When
> finished, the station will have three refurbished longwave transmitters
> (formerly
> installed at U.S. Navy facilities), two refurbished 60 kHz antenna systems,
> a new
> backup generator and emergency power supply system, and other new equipment
> to improve
> signal strength and reliability. The upgrade has progressed in phases; the
> first
> involved replacing the original LF transmitters with the first of the more
> powerful
> refurbished units, along with rebuilding the first antenna system. This
> phase raised
> the radiated power from 13 kW to 23 kW in December 1997. Next, an additional
> transmitter
> was brought on-line to provide stand-by capability and improve broadcast
> reliability.
> Additional improvements allowed for an increase in radiated power to 30 kW
> by
> December 1998. The final phase of the upgrade involves installing a third
> transmitter
> and refurbishing the second antenna system. Control systems will be
> installed with
> the aim of operating two transmitters into two separate antennas
> simultaneously. These
> transmitters will be broadcasting the same 60 kHz signal, but the result is
> expected
> to be an increase in radiated power to 45-50 kW for the station. This phase
> of the
> WWVB upgrade is expected to be completed by October 1999.
>
> Click on the links below to see pictures of the upgrade and to check planned
> service
> disruptions.
>
> NOTE: On 6 August 1999 at 0130 UTC WWVB began broadcasting at 50kW (up from
> 27 kW)
> to test the two antenna system. During the week of 16 August and 23 August
> the power
> will be reduced to 27 kW to complete work on the second antenna system. Any
> changes
> to this schedule will be posted as soon as possible. Click on the "Status of
> WWVB
> operations..." link below for additional information
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> Status of WWVB operations/planned service disruptions
> Pictures of the WWVB upgrade
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> Questions? Click on the hyperlink to send mail: nist.radio@boulder.nist.gov
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>
> 73 de Gamal