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Standard frequency and time signal service (short: SFTS) is, according to Article 1.53 of the International Telecommunication Union's (ITU) Radio Regulations (RR), [1] "A radiocommunication service for scientific, technical and other purposes, providing the transmission of specified frequencies, time signals, or both, of stated high precision, intended for general reception".
Radio clocks depend on coded time signals from radio stations. The stations vary in broadcast frequency, in geographic location, and in how the signal is modulated to identify the current time. In general, each station has its own format for the time code.
The telegraphic distribution of time signals was made obsolete by the use of AM, FM, shortwave radio, Internet Network Time Protocol servers as well as atomic clocks in satellite navigation systems. Time signals have been transmitted by radio since 1905. [12] There are dedicated radio time signal stations around the world.
A standard frequency and time signal service is a station that operates on or immediately adjacent to 2.5 MHz, 5 MHz, 10 MHz, 15 MHz, 20 MHz, and 25 MHz, as specified by Article 5 of the ITU Radio Regulations (edition 2012). [2] The US service is provided by radio stations WWV (Colorado) and WWVH (Hawaii).
The radio spectrum is the part of the electromagnetic spectrum with frequencies from 3 Hz to 3,000 GHz (3 THz).Electromagnetic waves in this frequency range, called radio waves, are widely used in modern technology, particularly in telecommunication.
Over the years, many radio navigation systems were designed using stable time and frequency signals broadcast on the LF and VLF bands. The best known of these navigation systems was the now-obsolete Loran-C , which allowed ships and planes to navigate via reception of 100 kHz signals broadcast from multiple transmitters.
These nonstandard time signal frequencies were chosen to avoid interference from WWV and WWVH. The signal is amplitude modulated, with the lower sideband suppressed (emission type H3E). The same information is carried on all three frequencies simultaneously including announcements every minute, alternating between English and French.
Five short pips and a long pip is broadcast between :55 and :00. The time signal broadcast at 15:00 EET is from Bulgarian Institute of Metrology. Canada – The National Research Council Time Signal was broadcast daily on Ici Radio-Canada Première at 12:00 EST/EDT and on CBC Radio One at 13:00 EST/EDT. It was Canada's longest running radio ...