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

Mark Spencer mspencer12345 at yahoo.ca
Mon Aug 27 22:53:27 EDT 2012


Thanks..  That seems like a good next step.

(Just to add to this, all three of the units have functional trim pots and two of three units will easily adjust to the correct frequency.)
> 
> Message: 7
> Date: Mon, 27 Aug 2012 22:24:06 -0400 (EDT)
> From: EWKehren at aol.com
> To: time-nuts at febo.com
> Subject: Re: [time-nuts] Datum 1000B's any hints ?
> Message-ID: <1003d9.2a828d17.3d6d85c5 at aol.com>
> Content-Type: text/plain; charset="US-ASCII"
> 
> 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.
> 
> Sent from my  iPad
> _______________________________________________





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