Tag Archives: DCF77

Ovenized crystal oscillator frequency stability


E. Schrama @ ejo60.wordpress.com uses an Arduino and a DCF77 time signal receiver to test the stability of an ovenized crystal oscillator running at 1 MHz.

In this experiment I will use an Arduino and a DCF77 time signal radio receiver to measure the stability of an ovenized crystal oscillator running at 1 MHz. It demonstrates that 50ppb (or 50 milliHerz) can be achieved on the short term, whereby an aging effect of 0.1 ppb per day is demonstrated with a 18 month long dataset. The output of the 1MHz oscillator is fed into a 248 counter and six 74HC165 parallel in, serial out (piso) conversion ICs that are controlled by an ATMEGA 2560, the circuit is described here. With this setup running at 1 MHz you get a rollover every 10 years, the resolution is 1 microsecond. In principle you could do this also with an Arduino but I decided for this set-up since I already had most of the components left over from an earlier experiment.

Ovenized crystal oscillator frequency stability – [Link]

Arduino DCF77 Master Wall Clock


by oliverb @ instructables.com:

Time displayed on large 1″ (26mm) 7 segment displays with secondary 4×20 LCD information display. The clock can be used stand alone or provides the following pulses to drive slave clocks 1 sec alternating, 30 sec, 1 min , 1 hour, 24 hr, 15 min chime of quarter hours, hourly chime of hours.

An Arduino 328 Microprocessor is used to decode and display time & date from the DCF77 “Atomic” Clock in Mainflingen near Frankfurt Germany.
The DCF77 signal is decoded using the fantastic new DCF77 library written by Udo Klein meaning the clock stays in sync and keeps perfect time even with a massive amount of noise on the received DCF77 signal. Udo Klein’s DCF77 library also continually “Auto Tunes” the quartz crystal so in the rare event the signal can’t be decoded the clock remains accurate within 1 sec over many days.

Arduino DCF77 Master Wall Clock – [Link]

DCF77 to USB converter

Jürgen Beisert writes:

I like the handy DCF77 signal. In this project no clock should use it, instead the computers in my home network should be served by a precise time reference. Due to the fact most other interfaces are no longer available on modern computers, it uses the USB to forward the prepared DCF77 signal to the host.

DCF77 to USB converter – [Link]

Homebrew DCF-77 Signal Generator

www.changpuak.ch writes:

Well, our meetings take place on wednesdays at 10:30 (sharp). A radio controlled clock is used to determine whether you are late (and must bring a cake next time) or not. Unfortunately the identical radio controlled clock in my office always shows a different time :-(

After baking a lot of cakes, I thought about synchronising these disreputable clocks …

Homebrew DCF-77 Signal Generator – [Link]

Testing CMA-77-100 antenna with SYM-RFT-77 DCF77 receiver module

SYM-RFT-77 DCF77 module with standard antenna (60x7mm)

Using a better antenna to improve DCF77 reception on long distances

We are in the prototyping phase of building a Nixie clock using 1N-14 Nixie tubes. The clock is designed around a PIC16F886 MCU, 74141N BCD decoder/driver and CNY74 optocouplers using common circuit topology. High DC voltage (+ 180VDC ) is generated using MAX1771 step-up switching regulator, which is quite efficient (if you use appropriate components).

Our clock will have some nice features:

  • Compact design
  • Manual time configuration
  • DCF77 time synchronization
  • Sync success indicator
  • HV shutdown during sync (to reduce noise received by DCF module)
  • Super-capacitor time backup
  • Thermal protection
  • ICSP connector etc.

When clock is complete we will release it as open source-hardware here at Electronics-Lab.com

We decided to use DCF77 signal as time reference for two main reasons, it’s quite easy to receive it and it’s very accurate for the reason that carrier signal is generated from atomic clocks.

But, what about receiving and decoding DCF77 signal?  Continue reading Testing CMA-77-100 antenna with SYM-RFT-77 DCF77 receiver module

Homemade 77.5 kHz DCF77 time signal transmitter

Matthias Franz writes:

The time manipulator is the little brother of the time signal transmitter located in Mainflingen close to Frankfurt in Germany. The very low frequency transmitter  located there has an output power of 50 kW and is called, in accordance to its call sign, DCF77 (similar to HBG, MSF, RWM and WWV, WWVB, WWVH). The transmitter is operated by the Media Broadcast GmbH and transmits on 77.5 kHz the official time signal for Germany. The medium range is stated with 2’000 km.

My time manipulator however offers some more functionalities. It’s the true alternative if you have difficulties to find your flux capacitor or your local electricity supplier canceled your contract after you had difficulties to pay off for the 1.21 GW.

Homemade 77.5 kHz DCF77 time signal transmitter – [Link]

DCF77 Simulator

www.sundgren.se writes:

The DCF77 Simulator is a combined simulator and demonstrator. It generates DCF77 time code at the same time as it displays the code in different views. The time code to be generated can be set to any time between 2000-01-01 and 2099-12-31.

The simulator can control DCF clocks via two interfaces:

  • Electrical
  • Radio-signal via a built in low-power transmitter

DCF77 Simulator – [Link]