The clockmodule as sold by Conrad (b.nr. 641871 - 89) for about 12 euro in the Netherlands is a nice tiny module that keeps track of the time very accurate due to the built in DCF-77 receiver. The idea was to see if this module could be used instead of the DCF-77 receiver that goes for 10 euros over here. Besides of having a smaller module the great benefit lies in the fact that it is a complete clock with a small LCD screen to show the exact time (good when testing freshly built nixie clocks!!!).
The module comes with a small leaflet that tells you fairly nothing about whats inside so after a initial fireup with a CD2032 battery i pried up the little case quite easy using the 4 notches in the case with sharp tweezers. Carefully lifting the back cover reveals the PCB board with the attached LCD that could be removed from the case very simple. Next thing was to find the DCF-77 signal using a scope. First testpoint was the large blank copperspot between U1 en U2 and Bingo: a nice (inverted) pulse (100 mS and/or 200 mS) sharp edged pulse was the result. Adding a little logic-converter to make it TTL level was enough to make this a fully functional DCF-77 receiver WITH its own display. Looking at the signal i must say: The quality of its signal is even better than that of the DCF-77 receiver module as sold by the same company.
Conrad DCF-77 module 641871 - 89
(photos a further description will follow soon)
