[time-nuts] Man with too many clocks.

EB4APL eb4apl at gmail.com
Fri Nov 4 17:07:03 UTC 2016


A bit OT, but regarding your Rb, some units needs to be powered thru 2 
pins, one is used only for the 10 MHz output buffer, if remember it 
correctly. Which is your model number?

Ignacio EB4APL


El 04/11/2016 a las 16:35, Peter Reilley escribió:
> I gave up on trying to use the GPS 1 PPS signal to calibrate the 10 
> MHz OCXO's that
> I have.   The reason that others have pointed out is that the 
> uncorrected 1 PPS
> signal from the GPS is has just a little too much a jitter to use it 
> for calibration
> with your eye using a scope.   If it were sawtooth corrected then it 
> would be better
> but you really need a GPS disciplined oscillator.
>
> Not to be outdone, I brought out a rubidium oscillator that I had put 
> away because
> it did not appear to work properly.   It only put out a 1 PPS signal 
> and nothing else.
> I compared that with the GPS PPS and could get a good comparison on 
> the scope.
> The rubidium drifted about 40 nS over 12 hours.   So it seemed to be 
> good.
>
> With that I could adjust the OCXO's in my 5370's.   The spec for the 
> HP 5370B with
> a HP 10811 OCXO is better than 1 X 10^-10 RMS for 1 sec average. That 
> is, it should
> take more than 1,000 seconds for one 10 MHz wave to shift by 360 
> degrees.   That
> is very hard to do using the screw adjustment in the OCXO.   Even the 
> slightest
> movement possible will cause a frequency change greater that is 
> spec'ed.   How
> do cal labs do it?
>
> My HP 5370A has a 10544 OCXO which is spec'ed for short term stability of
> better than 1 X 10^11 for 1 second.   Even better than the 5370B! The 
> adjustment
> screw is much coarser and it is not possible to get any better than a 
> few seconds for
> one cycle phase shift of the 10 MHz OCXO against the standard. It 
> seems that I can't
> get even close to the spec.
>
> These have been running for a few days.   It that enough?
>
> Pete.


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