[time-nuts] FE-5680A Mechanical Question

[Bob Camp]

Hi

I think it would be worth the effort to try dithering the DDS commands into
the Rb while measuring ADEV. You *might* find that you can do it with little
or no impact on the unit's stability. If so it takes out some modification
effort and should make the controller cheaper. 

Bob

-----Original Message-----
From: time-nuts-bounces at febo.com [mailto:time-nuts-bounces at febo.com] On
Behalf Of EWKehren at aol.com
Sent: Thursday, January 12, 2012 10:43 AM
To: time-nuts at febo.com
Subject: Re: [time-nuts] FE-5680A Mechanical Question

Bringing out the C field in my estimation does not effect long or short  
term. External magnetic field I think is a joke. An other option is a loop 
that  generates a tuning word for the DDS but that means your steps are 7
E-13.
Bert Kehren
 
 
In a message dated 1/12/2012 10:34:10 A.M. Eastern Standard Time,  
davidwhess at gmail.com writes:

I was  more interested in the technical details of how to adjust the
output of a  RbO without sacrificing the short and long term stability.
I have seen a  few designs that used a DDS to generate the 10 MHz
output which lends  itself to this but they all suffer from DDS and
tuning noise.  I see  now that the RbO can be adjusted with an external
magnetic field.

On  Thu, 12 Jan 2012 07:34:44 -0600, "J. L. Trantham"  <jltran at att.net>
wrote:

>David,
>
>I have been  following discussions on the list about a GPSDRbO for a year  
or
>so.  Some interesting challenges and probably best implemented  in a 
'stable'
>environment rather than portable operation but as best I  can tell, it 
would
>require a very stable and good antenna location,  stable and clean power, 
and
>I was thinking of using something like an  LPRO-101 with an Ext C Field
>input, a Shera type controller, and a GPS  timing receiver, though, I 
suspect
>there are likely to be some  'multi-tasking' receivers out there that will
>look at several sources  including GPS, GLOSNASS, etc.
>
>While the project might be fun,  for portable work, it is likely far easier
>and probably just as good  (almost), to use a Tbolt.
>
>In any event, something to think  about for the future.
>
>Joe
>
>-----Original  Message-----
>From: time-nuts-bounces at febo.com  [mailto:time-nuts-bounces at febo.com] On
>Behalf Of David
>Sent:  Wednesday, January 11, 2012 11:12 PM
>To: Discussion of precise time and  frequency measurement
>Subject: Re: [time-nuts] FE-5680A Mechanical  Question
>
>
>How would a GPSDRbO work?  Phase lock the  DDS output to the GPS? Phase 
lock
>a VCXO to the GPS and then phase lock  to the RbO on loss of GPS lock?
>
>On Wed, 11 Jan 2012 22:55:58  -0600, "J. L. Trantham"  <jltran at att.net>
>wrote:
>
>>Bill, Brian, Bill, and  Peter,
>>
>>Thanks for the info.  All I need now is a  'project' to incorporate the 
>>unit into.
>>
>>In  the back of my mind, I have the thought of a 'box' that will be  
>>battery powered or 110 VAC powered (perhaps with an internal SLA  
>>battery) and include a GPSDO and Rb unit (possibly a GPSDRbO) for  the 
>>purpose of a 'reference' for portable operation in the  microwave  
>>regions.
>
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