[time-nuts] Spectracom 8170 -> SWCC clock

Jim Hickstein jxh at jxh.com
Fri Jan 20 17:23:16 EST 2012

I have a Spectracom 8170 in the living room (who doesn't?), and a Western Union 
time-service clock, a.k.a SWCC clock -- a nice one, in a 3-foot-high wood case. 
  I've been watching TV with this combination for years and years but never got 
around to feeding a pulse from the 8170 to discipline the other one. Now that 
Western Union no longer provides the service. :-)  But it just begs to be done.

I did draw up a TTL circuit, once (on a napkin, naturally, which I have now 
misplaced), that could live inside the 8170.  I figured out the minimum number 
of inputs needed to detect when the MM:SS LED displays said 00:00 (for one 
second).  It would close a relay, which could feed the winding-battery power to 
the hour-set solenoid down a pair of wires from 10 feet away.  But I never built it.

A little over a year ago the TS clock was getting gummy and free-running slower 
and slower, so I sent it to the clock hospital.  It's back and free-running 
nicely, so maybe it's finally time I did this.  Anyone got a better idea than my 
little TTL circuit, on a breadboard inside the 8170?  I'd like to get it across 
the rear panel without cutting a new hole, if I can avoid it.  But maybe the 
right connector would do.  Another time-code receiver in the TS clock, e.g. a 
GPS module that provides a relay closure for 1 second on the hour (if such 
exists) might be neater.  But the living room faces north.

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