DCF77 is a longwave time signal radio station. The callsign stands for D=Deutschland (Germany), C=long wave signal, F=Frankfurt, 77=frequency: 77.5 kHz. It is run by The Physikalisch-Technische Bundesanstalt. Longwave radio frequencies are those below 500 kHz, which correspond to wavelengths longer than 600 meters. ... A time signal is a visible, audible, mechanical, or electronic signal used as a reference to determine the time of day. ... In broadcasting and radio communication, a callsign or call sign (also call letters) is a unique designation for a transmitting station. ... The Physikalisch-Technische Bundesanstalt (PTB) is based in Braunschweig and Berlin. ...

DCF77 radio signals (set by an atomic clock) are broadcast on 77.5 kHz from Mainflingen, Germany, about 25 km south-east of Frankfurt. The signal can be received from a distance of 2000 km. There are two transmitters so it is rarely off the air. Atomic clock Chip-Scale Atomic Clock Unveiled by NIST An atomic clock is a type of clock that uses an atomic resonance frequency standard as its counter. ... Mainflingen is a small town of about 3800 inhabitants, part of the municipality Mainhausen (near Frankfurt am Main) in Hesse, Germany. ...   Frankfurt am Main? [ˈfraÅ‹kfÊŠrt] is the largest city in the German state of Hesse and the fifth-largest city in Germany. ...

Radio clocks are popular in this region and use DCF77's signal to set their time automatically.
A radio clock A radio clock is a clock that is synchronized by a time code transmitted by a radio transmitter connected to a time standard such as an atomic clock. ...

A radio clock A radio clock is a clock that is synchronized by a time code transmitted by a radio transmitter connected to a time standard such as an atomic clock. ... BPM is the Peoples Republic of Chinas national time signal service, operated by the Chinese Academy of Sciences. ... Chu could refer to: The Chu river valley in modern Kyrgyzstan. ... Over fifty GPS satellites such as this NAVSTAR have been launched since 1978. ... HBG Prangins is a large transmission facility near Prangins, Switzerland. ... JJY is the callsign of a longwave time signal radio station similar to WWVB. The station is located in Japan, operated by a branch of the Japanese government known as the National Institute of Information and Communications Technology. ... The MSF time signal is a broadcast from the VLF transmitter Rugby near Rugby, Warwickshire based on time standards maintained by the British National Physical Laboratory. ... RWM is the callsign of a shortwave radio station in Moscow, Russia. ... VNG was Australias national time signal service, and operated on 2500, 5000, 8638, 12984, and 16000 kHz. ... WWV is the callsign of NISTs shortwave radio station located in Fort Collins, Colorado. ... WWVB is a special NIST time signal radio station in Fort Collins, Colorado, co-located with WWV. WWVB is the station that radio-controlled clocks throughout North America use to synchronize themselves. ... WWVH is the callsign of NISTs shortwave radio time signal station in Kekaha, on the island of Kauai in the state of Hawaii. ... YVTO is the callsign of the official time signal from the Juan Manuel Cagigal Naval Observatory in Caracas, Venezuela. ...

External links

• DCF77 Atomowy czas w Twoim PC
• Official DCF77 web page at the PTB
• The atomic clock in Frankfurt/Main Germany
• PTB FAQ on Time
• Time code description