[time-nuts] LTE-Lite module and the pendulum...

Burt I. Weiner biwa at att.net
Tue Oct 21 18:10:44 EDT 2014


The DATUM 9390's I have came from the Sieko pager watch project that 
I was involved in back in the mid to late 90's.  As I recall, even 
when the DATUM clocks were new we'd have to adjust the oscillators 
periodically to keep them within lock range.  The center of the DAC 
was around 27000 and they'd wander about 10000 plus or minus.  They'd 
sometimes wander out of lock at plus or minus about 15000 and one of 
us would have to make a trip to some transmitter site to re-set the 
clock and re-center the Vectron module.  The adjustment was 
accessible through a hole in the back of the clock.  As I recall, you 
could give the oscillator a half turn one way or the other without 
causing too much distress to the clock.  This held true with my two 
units until the one oscillator developed the adjustment problem.  Not 
knowing what was really inside the Vectron, I attributed the problem 
to a defective or cracked piston capacitor.  The adjustment certainly 
had the feel of a piston capacitor.

Since I made the modifications I described, the DAC sits within about 
10 of 27450, and that's where my units are happy.  By the way, I've 
got two 1.5 KVA UPS's in my shoppe, one for each clock.  They'll run 
for a long time on those.


>From: Said Jackson <saidjack at aol.com>
>Subject: Re: [time-nuts] LTE-Lite module and the pendulum...
>Great insight thanks. You nailed it: out with the old oscillator and 
>in with one that doesn't have that problem.
>Btw the mechanical tuning issue you mentioned is essentially the 
>same exact problem: even the slightest turn will make the frequency 
>jump too high or too low. It can drive you (and the loop) crazy 
>trying to get it on-frequency.

Burt I. Weiner Associates
Broadcast Technical Services
Glendale, California  U.S.A.
biwa at att.net

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