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DCF77 Signal Reception

reception, distribution & monitoring of the DCF77 signal for multiple Clocks

above my DCF77 Receiver Module from http://www.pvelectronics.co.uk


I now use a single DCF77 receiver for all my clocks and have fitted a larger aerial to improve reception.

The aerial is located in the roof of my house away from any electrical noise. The 3.3v signal from the receiver is fed into a digital

repeater circuit built into my Pragotron Master Clock. The 3.3v signal is duplicated over 5 outputs and changed to 5v and can feed up to 10 DCF77 decoders.


PV Electronics DCF77 Receiver Module connections

Connections from left to right

 1.VDD  2.TCON  3.PON  4.GND  5.NC

Provides output in an inverted format (output is low, and goes high once per second).

Low power standby mode - connect PON to Vdd. Connect PON to GND for normal operation.



DCF77 Signal Repeater

The receiver feeds all my clocks via a signal repeater circuit made up of inverters

A 4049UB Hex inverter is used with the 1st inverter inverting the 3.3v DCF77 signal.

This inverted output is fed into all the 5 remaining inverts giving 5 duplicate outputs at 5 volts.

Each 5v output can drive 2 Arduino clocks.



DCF77 Signal Quality Monitoring

The signal from the repeater is monitored minute by minute by my Binary Clock

When the incoming signal (50 pulses meteo pulses not checked as they are encoded ) matches the expected signal 100%

5v is output from pin 15 of this clock to a GPIO pin on the WIFI port of my Arduino Radiation Monitoring Station.

If the signal is not 100% correct then 0v is output.

This 1 or 0 uploaded to Thingspeak and Sparkfun data by the WIFI board (ESP8266).


Live charts showing DCF77 signal reception in Kenley UK

1 = all 60 bits of data received with no errors in the last minute. 0 = 1 or more data bits received in the last minute had an error.



There is also a Thingspeak app for Android phones with a Widget to show live data on any home screen or graphs for any sensor data.

Screenshot below left shows the live Widget with data from my Arduino Radiation Monitor and DCF77 signal Quality.

By selecting the graph symbol below each number brings up the graph screen for each number below right.




below Thingspeak "ThingView" App

Just enter your or any other channel ID into the app and you can see all your sensors as graphs.