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The time signal and standard frequency stations transmit pratically continuously
standard time intervals, standard radio frequences, time announcements, radio
propagation forecasts, etc.
These signals can be used, for example, in obtaining accurate time, in checking
the calibration of a radio receiver, and in gaining information on propagation
conditions.
The transmissions are usually realized in the frequencies of
2.5 MHz, 5 MHz, 10 MHz, 15 MHz, 20 MHz, 25 MHz, or 5 to 10 MHz around these
frequencies, within the frequency ranges allocated for this service.
These stations are usually operated by research centers in their countries.
Below are listed some time signal and standard frequency stations:
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WWV:
U.S. station operated by NIST (National Institute of Standards and Technology).
Its transmitters are located near Denver, USA.
This station transmits on
5 MHz, 10 MHz, 15 MHz (10 KW power), and
2.5 MHz, 20 MHz (2.5 KW power).
The time announcements are said by a male voice,
at minutes 0 and 30 in each hour.
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WWVH:
U.S. station operated by NIST (National Institute of Standards and Technology).
Its transmitters are located in Maui, Hawaii, USA.
This station transmits in the same frequencies used by WWV, except 20 MHz.
In order to avoid confusion with WWV,
the time announcements are said by a female voice,
at minutes 29 and 59 in each hour.
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CHU:
Canadian station operated by NRC (National Research Council).
Its transmitters are located in Ottawa, Canada.
This station transmits on 3330 kHz, 7335 kHz and 14670 kHz
(hence using frequencies placed out of the bands allocated for this service),
with power transmission of 3 kW, 10 kW and 3 kW, respectively.
The time announcements are given in English and French each minute.
Also, a digital time code is presented between the seconds 31 and 39.
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Observatório Nacional:
towards its Divisão do Serviço de Hora (DSHO/ON), it is
responsible by the generation and dissemination of the official time in Brazil.
The time signals are divulged through own transmissions in HF and VHF,
by radio stations, Internet, phone services.
Its transmitters are located in Rio de Janeiro, Brazil.
According information available (dated 1996),
the transmissions are realized on 8721 kHz
(at 0:25 UTC, 11:25 UTC, 13:25 UTC, 18:25 UTC, 20:25 UTC, 23:25 UTC,
during five minutes), and on 160.23 MHz, 171.13 Mhz, 166.53 MHz,
with 20 kW power (continuous transmission).
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LOL:
time signal station from Argentina, it is operated by
Servicio de Hidrográfica Naval,
Observatorio Nacional.
Transmits since Buenos Aires, Argentina,
on 5 MHz, 10 Mhz, 15 Mhz (2 kW power).
The identification is presented at minutes
3, 4, 8, 9, 13, 14, etc, in each hour.
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