[time-nuts] Using GPS to Fine Tune a Rubidium Frequency Standard.

[EWKehren at aol.com]

Depends on what you call close. 1 E-14 steps are very doable. That does not 
 mean that that is the accuracy because once you go below 1 E-12 you have 
to  worry about barometric pressure and humidity assuming you already have  
temperature control.
Bert
 
 
In a message dated 3/21/2014 2:58:32 P.M. Eastern Daylight Time,  
paulswedb at gmail.com writes:

Chris,
Not to often I can offer useful advice. But I know others  on time-nuts have
experimented with the digital dacs in the RBs. There was  program quite a
while ago that let you tweak them. Essentially it seems you  can not get
them exactly on because of the DAC step function.
Granted  they are crazy close, but this is  time-nuts.
Regards
Paul.
WB8TSL


On Fri, Mar 21, 2014 at  2:24 PM, Chris  Albertson
<albertson.chris at gmail.com>wrote:

> I'm working  on doing exactly this right now.   There is a "ton" of
>  information on how to build a GPSDO where the oscillator is an OCXO.
>  But it is almost exactly the same thing to build a "GPSDRb"     The
> only change is that rather then sending a command to control a  DAC
> that in turn controls the OCXO's EFC pin you send data to control  the
> Rb.    Also of course use some different  constants.
>
> There seem to be two different class of Rb.   One takes an EFC just
> like the OCXO so the controller looks just like  a GPSDO and the other
> class of Rb accepts serial commends to adjust  the frequency.  These
> have an internal DAC.  But either way  the logic is the same.
>
> On Fri, Mar 21, 2014 at 6:20 AM, Anders  Time <anderstime at gmail.com> 
wrote:
> > Does anyone have a copy  of the QEX 2013 november article(Bill Kaune)
> "Using
> > GPS  to Fine Tune a Rubidium Frequency Standard"?
> >
> > I´m  really interested in this subject, but I can´t find this magazine 
in
>  > Sweden. I have contacted QEX, but it is very difficult to buy
>  back-issues.
> >
> > Have any one built this frequency  standard and can tell me more about 
the
> > project?
> > You  can access the source code for the project here:
> >
>  
http://www.arrl.org/files/file/QEX%20Binaries/2013/November_13/11x13_Kaune_PIC_Code.zip
>  >
> > /Anders
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>
>
>  --
>
> Chris Albertson
> Redondo Beach, California
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