DCF77 is a longwave

Mainflingen longwave transmitter

Mainflingen longwave transmitter is a large facility for commercial longwave transmissions at Mainflingen, Hesse, Germany, which was built in 1956. It uses several T- and triangle antennas, which are mounted on guyed masts of lattice steel, insulated against ground...

 time signal

Time signal

A time signal is a visible, audible, mechanical, or electronic signal used as a reference to determine the time of day.-Audible and visible time signals:...

 and standard-frequency radio station. Its primary and backup transmitter

Transmitter

In electronics and telecommunications a transmitter or radio transmitter is an electronic device which, with the aid of an antenna, produces radio waves. The transmitter itself generates a radio frequency alternating current, which is applied to the antenna. When excited by this alternating...

 are located in Mainflingen

Mainflingen

Mainflingen is a small settlement of about 3800 inhabitants, a constituent community of the municipality Mainhausen in Hesse, Germany....

, about 25 km south-east of Frankfurt am Main, Germany

Germany

Germany , officially the Federal Republic of Germany , is a federal parliamentary republic in Europe. The country consists of 16 states while the capital and largest city is Berlin. Germany covers an area of 357,021 km2 and has a largely temperate seasonal climate...

. It is operated by Media Broadcast GmbH (previously a subsidiary of Deutsche Telekom AG), on behalf of the Physikalisch-Technische Bundesanstalt

Physikalisch-Technische Bundesanstalt

The Physikalisch-Technische Bundesanstalt is based in Braunschweig and Berlin. It is the national institute for natural and engineering sciences and the highest technical authority for metrology and physical safety engineering in Germany....

, Germany's national physics

Physics

Physics is a natural science that involves the study of matter and its motion through spacetime, along with related concepts such as energy and force. More broadly, it is the general analysis of nature, conducted in order to understand how the universe behaves.Physics is one of the oldest academic...

 laboratory. DCF77 has been in service as a standard-frequency station since 1959; date and time information was added in 1973.