DCF77 - Definition and Overview

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.

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 2 transmitters so it is rarely off the air.

Radio clocks are popular in this region and use DCF77's signal to set their time automatically.

External links

• The atomic clock in Frankfurt/Main Germany (http://www.dcf77.de/)
• PTB FAQ on Time (http://www.ptb.de/en/blickpunkt/_infoszurzeit.html)
• Time code description (http://www.eecis.udel.edu/~mills/ntp/dcf77.html)