DIY high precision clock synchronized with an atomic clock
Here is a DIY high precision clock that is synced to the DCF77 atomic clock long wave radio signal. The radio signal is broadcast form Frankfurt at 77.5 KHz and has a reach of about 2000 Km.
DCF77 is the name of a german radio station on 77.5 KHz, which gives official time and date from an atomic clock located in Francfort. The time and date is coded into a 59 bit length frame, and is sent on the air through an antenna, by a 50 kilowatt power amplifier.
A simple and tiny receiver can catch the signal, from approximately 2000 kilometers around the antenna. The pulse contained in the radio frequency signal is filtered by the receiver : a 100 ms pulse is a value of 0, a 200 ms pulse is a value of 1, there is a pulse per second, and the last second of a minute lacks (there is 2 seconds without pulse) to allow synchronization with the next minute.
Via Hacked Gadgets.
This entry was posted in clock, DIY and tagged clock, DCF77, DIY.
Comments
It is a bummer that the WWVB module that digikey and sparkfun used to sell is no longer available — does anyone know of an alternative?
OR! Does anybody know how to build an antenna for this specific use :)
At that sort of frequency, just a long line would be fine.
Don’t these DCF77 receivers come with a ferrite loop antenna? If not, one should be available separately.
My reason for asking was how to build the antenna bit yoruself. Buying/salvaging the Ferrite core with some wire around it, add some components, hook it up to a micro.
Very incidentally I was searching for the last two days how to easily build an antenna assembly, but everybody speaking of DCF77 uses pre-build antenna’s with some chip on it.