[time-nuts] Next upgrade
EWKehren at aol.com
EWKehren at aol.com
Fri Nov 24 11:58:56 UTC 2017
A few comments I forgot.
Most Rb's can use a clean up loop, we are experimenting with Wenzel's 600
second loop recently posted here. Exceptions are the HP 5065 the optical
unit is the source of the performance, Corby experimented with different OCXO,
performance remained the same. Loop time constant is 0.01 second. There is
also no way to improve PRS 10 performance it will stay at 2 E-12 because
of DAC resolution.On related subject Corby and I community regularly and he
mentioned in all his 5065 work he has never experienced a bad lamp!!
We focus our Rb work on FRK/M100 because next to the 5065 it has the
largest cell and it is easy to work on. Focus right now is OCXO and reducing
time constant. If positive results we may look at inserting an optical filter,
Corby did experimented with it but forgot reducing the time constant.
Bert Kehren
In a message dated 11/22/2017 7:26:57 P.M. Eastern Standard Time,
k8yumdoober at gmail.com writes:
For the most part the SRS-10 is a nice choice, although I'd always be wary
of buying a
used one.
My only real beefs are that the tuning granularity is rather coarse, about
2E-12, and the
disciplining loop seems to be a bit aggressive so that the poor oscillator
gets jerked
around quite a bit by the GPS. This makes for rather ugly-looking plots of
time error
over time.
The above comments are derived from about 3 years of operating one as a hot
emergency spare at the Arecibo Observatory against the day when the H-maser
crashed abruptly. In this case the SRS-10 was embedded in an FS725 which
we
bought new.
Dana
On Wed, Nov 22, 2017 at 4:16 PM, Jerry Hancock <jerry at hanler.com> wrote:
> Three questions:
>
> 1) Now that I’ve split my Lucent RFTG-U into a REF0 and REF1 unit with
> both supplying 10Mhz and 1PPS, is there a way to combine the outputs or
> some other technique to improve the short and/or long term performance?
>
> 2) I’ve become interested in Rubidium Disciplined Oscillators recently
and
> was now thinking of purchasing one of the PRS-10 that I see on Ebay. If I
> did that and replaced one of the DOCXOs from one of the Lucent boxes,
what
> impact would this have on the overall performance both with and without
> (when in hold-over)? Basically, is it worth the money to upgrade one of
> the boxes to a Rubidium disciplined oscillator assuming the GPS signal is
> rarely lost?
>
> 3) Figuring the PRS-10 will cost around $250 when all is said and done,
is
> there a better option to improve my GPSDO system?
>
> I basically use the GPSDO as a reference for any equipment that takes an
> input. I have no monetary need for a reference, just an interest.
>
> Thanks.
>
> Jerry
>
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