[time-nuts] Isotemp 134-10 & Fury

Richard Moore richiem at hughes.net
Mon Nov 3 09:05:04 UTC 2008


The Isotemp 134-10 *may* have a screw in the side of the case that  
gives access to a trimmer for the frequency. You can set your Fury to  
an EFC output of 2.5V and try adjusting the trimmer for 10MHz or as  
close as you can get it. This will optimize your control range from  
the Fury, with the proviso that the Isotemp's control slope is not  
linear. My OFC version does not have the access port, but it it a  
much earlier model than the Isotemp 134. The Isotemp has a positive  
control slope -- increasing EFC increases frequency. Mine has an EFC  
sensitivity of about 2E-7 per Volt.

Dick Moore


> From: Matt Osborn <_kc0ukk at msosborn.com_  
> (mailto:kc0ukk at msosborn.com) >
> Date:  November 1, 2008 23:28:34 PDT
> To: time-nuts <_time-nuts at febo.com_ (mailto:time-nuts at febo.com) >
> Subject:  [time-nuts] Jackson Labs Fury & Isotemp  OCXO134-10
> Reply-To: Discussion of precise time and frequency  measurement
> <_time-nuts at febo.com_ (mailto:time-nuts at febo.com) >
>
> I think that I've managed to keep a low profile here, trusting  that I
> would learn more if I refrained from random  interjections of
> ill-informed thoughts.  However, there  comes a point in every  man's
> life...
>
> A year or two  ago, I took advantage of Said's offer and purchased one
> of  the Jackson Labs OEM external OCXO Fury units and am  
> attempting  to
> put it to work. I've decided to use an Isotemp OCXO134-10  oscillator
> and have several decisions which I would like to  vet with those of  
> you
> that have been down this road  before.
>
> The Isotemp unit has an EFC range  of 0 to 8 Volts; the Fury has an  
> EFC
> range of 0 to 5 volts.  Using my HP 53131A, I'm able to adjust the
> Isotemp to  10 MHz +- 5 mHz with an EFC voltage of 4.64 volts.  
> That  is
> within the adjustment range of the Fury, but I'm not sure  of the
> accuracy of the HP53131A.  Should I construct a  resistive network ala
> Brooks Shera to 'boost' the EFC range  just in case or would I be
> better off just using the Fury  'as is'?
>
> Secondly, the Jackson Labs advises  that since the Fury uses the
> external oscillator as its  clock, that the oscillator should be
> powered up before the  Fury itself.  I was hoping that I would be able
> to use  a single power switch to power both the oscillator and the   
> Fury
> simultaneously, but now I'm not so  sure.
>
> Finally, are there any of you that  have used the Isotemp OXCO134-10
> with the Fury?  Have  any of you worked out the various SERVO settings
> that the  Fury makes available?  I'm interested in the  DAC gain,  EFC
> scale, EFC dampening and Phase  compensation.
>
> Any and all advice will be  gratefully accepted.
>
> -- kc0ukk at msosborn  dot  com
>



More information about the time-nuts mailing list