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: [email protected]
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73 de Gamal
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