When the maladjustment is too large, the transmitter is taken out of service temporarily. This manifests itself in electrical detuning of the antenna resonance circuit and hence a measurable phase modulation of the received signal. Longer lasting transmission service interruptions are generally caused by strong winds, freezing rain or snow-induced T-antenna movement. Most service interruptions are short-term disconnections of under two minutes. With Media Broadcast GmbH, a temporal transmission availability of at least 99.7% per year or under 26.28 hours of annual downtime has been agreed upon. It is operated by Media Broadcast GmbH (previously a subsidiary of Deutsche Telekom AG), on behalf of the PTB. The transmitter generates a nominal power of 50 kW, of which about 30 to 35 kW can be radiated via a T-antenna.ĭCF77 is controlled by the Physikalisch-Technische Bundesanstalt (PTB), Germany's national physics laboratory and transmits in continuous operation (24 hours). In June 1973 date and time information was added.

It started service as a standard-frequency station on 1 January 1959. DCF77 is a German longwave time signal and standard- frequency radio station.

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