[time-nuts] Better than average Rb oscillator

[Bob kb8tq]

Hi

Cool !!

> On Feb 10, 2021, at 6:54 PM, Skip Withrow <skip.withrow at gmail.com> wrote:
> 
> Hello Time-Nuts,
> I just finished an almost 27 day run of one of my Rb oscillators and,
> at least, I was impressed.
> 
> This oscillator is a stock standard LPRO-101 with only one slight
> modification.  The 5k C-field pot was brought out external to the unit
> and replaced with a precision 500 Ohm 10-turn pot with fixed resistors
> on either side to make the total 5k.  The frequency change is about
> 1.62x10E-13 per division on the turns counting dial.
> 
> The oscillator IS in a controlled environment (with a little secret
> sauce poured on).

Ok, I’ll ask …. what’s the environment?

Bob

> 
> The oscillator is running completely open loop.  In fact, there is
> purposely nothing hooked to the EFC line.  During the run nothing was
> touched in the system.
> 
> There are two attachments.  The first is a TimeLab ADEV plot.  The 4
> hour plot is the oscillator against a free running 8602 measured with
> a DMTD and TICC (this gives the real short-term performance with the
> GPS noise removed).  The 26 day plot was done by logging the
> oscillator against GPS with a Thunderbolt every 15 seconds.  The phase
> data was imported into TimeLab.  Of course, this plot has the GPS
> noise in it as well, but gives a good indication of the unit
> long-term.
> 
> The second attachment is the phase data plot.  Over the almost 27 days
> it moved about 130ns.  And the curve looks reasonably parabolic, which
> would indicate the aging is pretty constant.  Aging calculates to
> about 4.15x10E-15 per day.  Reasonably good by my standards (but I'm
> trying to do better)!
> 
> When I monitor my HP5065A with a Thunderbolt side by side with this
> rubidium I can see the 5065A move with barometric pressure changes and
> ambient temperature changes much more than RUFUS.  And the 5065A
> flicker floor seems to be worse (but, of course, I haven't measured
> the 5065A yet).
> 
> Just had to brag a bit on this one.
> 
> Regards,
> Skip Withrow
> <RUFUS vs 8602 - ADEV.png><RUFUS vs 8602 - Phase Data.png>_______________________________________________
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