[time-nuts] Datum 1000B's any hints ?

EWKehren at aol.com EWKehren at aol.com
Tue Aug 28 02:24:06 UTC 2012

without any EFC I would expect it to be 1 Hz low. If less than 5 Volt  will 
get it on frequency I would use a 78L12 from your main supply followed by a 
 TI REF02. Worked for me.
Bert Kehren
In a message dated 8/27/2012 10:13:35 P.M. Eastern Daylight Time,  
mspencer12345 at yahoo.ca writes:

Wondering if anyone has any practical suggestions as to the  operation of 
stand alone Datum 1000B's.    Over the last 6 months or  so I've acquired 3 
of them and I haven't been that impressed with their  performance.   I've got 
a nicely running FTS 1050 and an 8600 series  bva along with time lab and 
some HP5370's so I'm reasonably confident in my  references and test setup.   

I've been powering them from  stand alone linear power supplies with 
separate supply and return leads for  the oven and electronics and have left them 
alone for several weeks at a  time.   I haven't touched the efc input yet 
and am wondering if  leaving that floating could be causing issues.   I also 
tried  running one of them from my stand alone 24 volt battery system which 
didn't  seem to help.

They all seem to be gradually getting better over time  but I'm thinking 
either I have three duds or there is something basic I'm  missing (ie. perhaps 
I need to connect the efc input ?).  I'm also  wondering what if anything 
to connect the case ground to.

The most  promising of the bunch from an adev perspective is also off 
frequency by  approx a hz or so but seems to be slowly drifting towards the 
correct  value.

Any comments would be appreciated.

Regards Mark  Spencer.

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