Daily Archives: 25th May

The Right Time

I’m quite fussy about the time.


These are three of the clocks in my house. If you click on the image to enlarge it you’ll notice that they all show exactly the same time, to the second.

In the Cumbrian countryside there is a 17kW 60kHz radio transmitter operated by the National Physical Laboratory connected to three caesium fountain atomic clocks that constantly broadcasts the current time and date. Once a day, at night for some odd reason, each of the clocks in my house synchronises itself with the broadcast time signal, keeping them accurate to 1 second in 1000 years. My watch does the same thing.

Recently one of my other clocks fell off the wall and broke, so I took that opportunity to take it apart.



This is the part that drives the hands, a highly accurate stepper motor.


But this is the true heart of the clock: the radio receiver and the 60kHz antenna. The ribbon wire to the left of the image carries information from the receiver to the clock’s motors.


You can just about make out the tiny radio crystal in the bottom right-hand corner of the circuit board.