time of the Federal Republic of Germany on
the long-wave frequency of 77.5 kHz. The
transmitter is located in Mainflingen near
Frankfurt am Main and, with its range of up
to 2000 km, supplies the majority of radio-
controlled clocks in western Europe with the
necessary radio signals.
As soon as the radio-controlled alarm clock is
supplied with power, it switches to reception
and searches for the signal from the transmitter
DCF77. If the time signal is received in sufficient
strength, the display shows the date and time.
The radio-controlled alarm clock switches on
several times a day and synchronises the time
with the radio signal from the transmitter DCF77.
In the event the signal is not received, e.g. during
a strong storm, the device continues to run
precisely and then switches to receiving mode
again at the next scheduled time.
51