[time-nuts] Thinking outside the box a super reference

Tim Shoppa tshoppa at gmail.com
Thu Nov 3 21:43:30 EDT 2016


Zero. But the answer is also zero for a Rb or Cs cell!


On Thu, Nov 3, 2016 at 8:59 PM, Bob Camp <kb8tq at n1k.org> wrote:

> Hi
>
> Ok, how many full performance Hydrogen Masers can you build (size is not
> an issue) and
> deliver for < $10,000 (2X Bert’s number) ?
>
> Bob
>
> > On Nov 3, 2016, at 8:55 PM, Tim Shoppa <tshoppa at gmail.com> wrote:
> >
> > It would obviously be larger than a homebrew Cs, but why not a homebrew
> > Hydrogen Maser Frequency standard?
> >
> > The commercial Cs units always seemed objects of pure miniaturized
> hi-tech
> > materials science magic, while the Hydrogen Masers I've seen seem much
> > larger-scale\ and more a matter of vacuum plumbing. Obviously the
> materials
> > cost for the copper microwave cavity will be very large, and I'm sure
> > Teflon-coating a quartz chamber is an art, but the pumps and magnets are
> > very familiar from my years in grad school working with plasma kettles
> and
> > mass spectrometers.
> >
> > Tim N3QE
> >
> >
> >
> >
> >
> > On Thu, Nov 3, 2016 at 4:07 PM, Bert Kehren via time-nuts <
> > time-nuts at febo.com> wrote:
> >
> >>
> >> Over the past there has been talk about building from  scratch high
> >> performance references. I think consensus was that it is out of  reach.
> In
> >> the mean
> >> time Corby is reworking an active maser which takes a lot of  know how.
> But
> >> let us look at his work on the super HP5065. It is able to  outperform a
> >> passive maser in the below 100 second range! Long term a proper  GPSDO
> >> should
> >> be possible to step in. We are working on it including pressure and
> >> temperature control. To make full use of it you also need to have the
> >> capability
> >> to monitor, record and analyze on a continuous basis preferably with out
> >> tying  up expensive equipment. We have the pieces in place and looking
> >> forward
> >> of  combining all the pieces and compare with Corby’s active Maser. We
> are
> >> back to  the GPSDO after being distracted by Tbolt performance. A third
> >> party
> >> is working  combining the GPSDO data stream with the data from the unit
> >> that
> >> generates  frequency, pressure and temperature data along with time to a
> >> USB stick, while  also be able to monitor with a PC.
> >> I know it is considered by some heresy but our lack of a  Maser and in
> >> Juerg
> >> ’s case no access to one, we try to overcome it with a GPSDO  tailored
> for
> >> Rb and Cs and control our Cs’s C field .
> >> There was a time that I did have a HP5065A but got rid of  it when I got
> >> some Cs’s. My best counter was A HP5345 and even with a Tracor 527  1
> >> second
> >> performance was not an issue. That changed when Corby introduced me to
> >> time
> >> nuts and frankly it was the first  time I learned about ADEV. But the
> >> HP5065A was gone. Now I have a cell  that Corby has plotted and time
> >> permitting
> >> may become a project.
> >> Let me get to the real issue. There are not enough  HP5065A’s out there
> and
> >> not affordable for all time nuts. Most are being kept  and are not for
> >> sale. But if a combined effort by many time nuts it MAY be  possible to
> >> recreate
> >> the guts of the HP5065A. The key word is MAY. 200 time nuts  be willing
> to
> >> invest $ 5000 each may get us there. The market does not justify  such
> an
> >> effort but time nuts keep bringing up discussions. All the other ideas
> >> kicked
> >> around in the past will cost more. There are some among us that know
> what
> >> it cost and who can make the key elements like lamps, cells, filters
> etc.
> >> Just a  thought outside the box and hopefully may turn in to a limited
> >> constructive  dialog. We will continue on our path, which include
> >> FRK/M100, HP5065
> >> and  Cs.
> >> We would not be capable to contribute technically on the  physics
> package
> >> but I would be willing to contribute financially and with  monitoring
> >> equipment even if I would not be around when finished.
> >> Bert Kehren
> >> _______________________________________________
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> >>
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