DCF77 Time Server

The DCF77 signal is the legal time signal of the Federal Republic of Germany and is derived from the atomic clocks of the Physikalisch-Technische Bundesanstalt (PTB) in Braunschweig, Germany. The transmitter is located in Frankfurt/Mainflingen and it distributes the DCF77 signal by long radio waves at a frequency of 77.5 kHz, within a radius of 1500 km.

The atomic clocks of the PTB are adjusted to TAI the International Atomic Time which is a high-precision standard based on the notional passage of proper time on earth's geoids. The accuracy of the DCF77 long radio wave signal is 1ms. To enhance the signal accuracy the PTB sends out a pseudorandom noise (PZF), like this a signal accuracy up to 1µs can be achieved.

The length of the antenna cable for Meinberg's DCF77 receivers can be up to 300m by using a standard RG58 cable. For longer distances the DCF77 Diplexer/Distributor DCF77 Distributor AV4 can be used.

Other important national Time Signals:

MSF: The UK long wave signal can be used as reference for time servers
JJY: Japanese long wave transmitter
WWVB: The time base for many applications in the United States

Meinberg Time Server with long wave AM or PZF receiver:

Advantages of long wave signal synchronized time servers:

Receipt with indoor antenna is possible, if the room is not too much shielded
Official local time
By using a Meinberg PZF receiver very good accuracy and frequency stability

Disadvantages of DCF77 time servers:

Transmitter range only 1500 km around Frankfurt/Mainflingen (Germany)
In areas / rooms with lots of metal, computers or high voltages the usage of an indoor antenna is not recommended