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[time-freq] RefLock II behavior

Owen, Michael Michael.Owen at Sensis.com
Wed Jun 21 12:33:38 UTC 2006

All -

Thanks for the input.  My (well, my employer's) setup is this: 

Fei-Zyfer GSync GPS RX w/1PPS output
RefLock II
  f_conf   = 00
  avg_conf = 00
  pps_pol  = 0
  ld_conf  = 5 (R5=0,R4=0,R3=0,R2=1,R1=0,R0=1)
OCXO is Wenzel Assoc 501-14217
(http://www.wenzel.com/datasheets/Onyx/501-14217.htm) Tuning range is
+/-4Hz 0-10 VDC
Freq counter is Agilent 53131A-02
(http://cp.literature.agilent.com/litweb/pdf/5967-6039EN.pdf) calibrated
last month.

I have changed R22 to 68K as per Peter G2XO(?) via Steve Bible because
the "stock" VTUNE range was insufficient.

Ideas are welcome!


Michael R. Owen, Ph.D.
Senior System Engineer
Sensis Corporation
(315) 634-3066 

|-----Original Message-----
|From: time-freq-bounces at lists.tapr.org 
|[mailto:time-freq-bounces at lists.tapr.org] On Behalf Of Robert McGwier
|Sent: Tuesday, June 20, 2006 9:48 PM
|To: TAPR time and frequency projects
|Subject: Re: [time-freq] RefLock II behavior
|Could you provide a little more description of your set up?  What is 
|your reference,  what is the tuning range on your VCO in frequency and 
| I can lock my oscillators using 1pps GPS or 10 MHz rubidium sing 
|modified Reflock I and it will NEVER be that far off.  What 
|you are see 
|is 0.15 ppm.  That is really messed up.   You should be seeing 
|one part 
|in 10^10 at least from GPS (say).  My PTS-160 synthesizer 
|locked to this 
|source is extremely stable.
|Owen, Michael wrote:
|> Dear friends,
|> Thanks to Steve Bible, I got my brain un-stuck and figured out how to
|> set the 0-ohm jumpers (I'll summarize everything in a couple of days 
|> when it's all finished and my shame has faded).
|> For right now, I have a question.  RefLock plus my pretty good OCXO
|> are trying to settle at 100 MHz but there are sharp spikes every few 
|> minutes.  Here's an image:
|> The time span is about 40 minutes.  Even after 3+ hours, the spikes
|> are still there (although more rarely).  Does anyone have an 
|idea how 
|> to get rid of them?
|> 73, W9IP
|> ------
|> Michael R. Owen, Ph.D.
|> Senior System Engineer
|> Sensis Corporation
|> (315) 634-3066
|> --
|> _______________________________________________
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|Laziness is the number one inspiration for ingenuity.  Guilty 
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