Tuesday, December 09, 2014

How to get MSF "radio controled" clocks on your boat to get time from GPS instead.

My boat has two nice shiny brass clocks with quartz movements. They are a pain to adjust as they are screwed on the wall and the easiest thing is to keep them on GMT but even then they need correcting. They just have cheap quartz movements and I thought of replacing them with radio controlled clocks that use the MSF time signal (which used to be called the Rugby atomic clock signal). The thing is that would only work a certain distance off shore. There are transmitters in Germany, USA and Japan, with different frequencies and protocols but not world wide. On the other hand we have an accurate time signal from GPS.

The MSF clock mechanisms are really cheap so there is a good reason to stick to that and I was wondering about feeding a time signal from the GPS.  Something that is a nice idea I wont get round too!

I have just found that someone has already done it!  Unusual electronics have a small device called a Chronoverter that converts time procols. In particular it can take NMEA data from a GPS and convert it to MSF - digital as well as the modulated carrier wave that can be coupled in to the antenna of a clock. Nice thing about this is you do not need to modify the clock. Hopefully just shield it from the real signal. As the clock has a brass case I am half way there I hope.


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