[time-nuts] Chronometer contest sponsored by IEEE Spectrum

Hal Murray hmurray at megapathdsl.net
Fri Nov 30 00:58:58 EST 2007

> Are surplus parts such as Ebay OCXOs OK? (That's an 'open market' to me!)

I got eight 3 MHz OXCOs for $32.  They don't have electric tuning, but the 
one I played with seems pretty stable.  It takes a significant dip if I grab 
the can with my fingers but there isn't any obvious 24 hour pattern.

Maybe there should be several categories:
  Sync to WWVB
  Sync to 60 Hz from the wall.
  Sync to GPS (you can get USB GPS units well under $100)

  Watch crystal - 32 KHz
  Other crystal
  Good local osc (TCXO, OCXO, ...)
  External frequency source - focus on display
    Say 10 MHz coax with power over the coax.

  Longest battery life (lowest power)

  Best accuracy per dollar
    measured over a month
    using Digikey's one-off pricing (or any major supplier)

  Coolest as determined by judge's whimsy.
    Any other categories the judges think appropriate.

  Built out of stuff in your junk box
    Only "junk" allowed
    Cesium OK if you already have one  :)

> Display should be  seven-segment LEDs

That seems like a strange restriction.  It cuts out a lot of innovation that 
could be done on the display.  It also mostly eliminates the battery powered 

Using the eye-ball to measure goodness of a clock seems like the wrong 
approach.  How about adding a PPS test point to the requirements?

> we're looking for a usable appliance, not just a  science project.

What's wrong with science projects?  DIY stuff is inherently a project.  
Sometimes it's science, sometimes art, sometimes engineering, sometimes just 


These are my opinions, not necessarily my employer's.  I hate spam.

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