Precision Timekeeping

Exact time keeping is a small obsession around here. A decade or more ago, I got an HP Z3801A GPS Receiver from E-Bay and it has worked very well. The point of this thing is not to tell you where you are, but to tell you what the time is. More specifically, it produces a 10MHz frequency reference signal which is typically accurate to within 1 part in a billion, along with a 1 pulse per second signal that is synchronized to GPS time to better than a microsecond. These signals can be used to drive other things - such as frequency synthesisers, counters, clocks, time servers ...

  • If you are interested in knowing more about the Z3801A this link will probably tell you all you need to know.
  • Some excellent software for communicating with a Z3801A can be found here.
  • My own software for displaying the Z3801A status generates the image shown below.






Two interesting Web sites run by the time obsessed are www.leapsecond.com and www.febo.com. There is some fascinating stuff there...