[time-nuts] Re: Creating a D.I.Y Rubidium Atomic Clock

[Bob Stewart]

Hi Adrian,
My link didn't come through the last time, so let's try this differently.

Re the Rb capsules, take a look at this ebay listing.  Is this what you were thinking of?  Just enter this number in the search field on ebay:  124012486501

Bob 

    On Wednesday, June 7, 2023 at 01:14:43 PM CDT, Adrian Godwin via time-nuts <time-nuts at lists.febo.com> wrote:  
 
 I have seen glass rubidium capsules on ebay a couple of years ago. None at
the moment and they were possibly in Russia. They were just a glass capsule
- no surrounding components, not even a coil, but they weren't particularly
expensive,. Certainly not HP-spares expensive.

Is such a thing useful (to provide 'the hardest thing') for Leo's project
if they reappear ?

On Wed, Jun 7, 2023 at 1:26 PM Magnus Danielson via time-nuts <
time-nuts at lists.febo.com> wrote:

> Hi,
>
> I agree with Rick and was about to make more or less the same comment.
>
> The glas package is the hardest thing to do, and there is also a certain
> magic to mix the buffer gas just the right way to frequency compensate
> the wall shift. Already there comes the aspect of knowing what wallshift
> you will get, so you need reasonable reproduceability in both the glass
> and pressure and mix in gases. To put that in other words, I am not THAT
> crazy, yet.
>
> Next level is the cavity you put the glas-ware into. The Q of that
> resonator is not irrelevant, so you want to handle that.
>
> There is a certain magic to the temperatures of the rubidium lamp and
> that of the rubidium filter. This has consequences on how the physical
> package is built. Some of this can be avoided today by using diodeds,
> and that may even open up for avoiding the tuned resonator, but brings
> in it's own set of issues.
>
> Achievable engineering challenges, but maybe hard to do as a hobbyist.
> The remaining temperature controls, FLL-lock of oscillator, synthesis
> have become more and more achieveable over the years. That has become
> hobbyist achieveable for sure.
>
> However, just *attempting* to study up on a subject like this forces you
> to learn alot, so even if you do not do a single soldering, you can have
> improved your knowledge.
>
> I would consider recycle an existing physical package that works and
> make modern electronics for it. That should be plenty of challenges and
> quite achieveable.
>
> Cheers,
> Magnus
>
> On 2023-06-07 02:26, Richard Karlquist via time-nuts wrote:
> > In a former life, I was on the design team of a mini rubidium standard
> > at Hewlett-Packard.  We built some working prototypes before it was
> > cancelled.  It was going to have the model number 10816.  I was the RF
> > person, but I worked very closely with the other team members.
> > Remembering what we had to go through to make "glassware", it is
> > inconceivable that you could do that as a "home brew" project.  And this
> > was the same HP facility that already made the 5065 rubidium standard.
> > The best you could hope to do is to start with a commercial "physics
> > package" as we called it, and make your own electronics for it.  Reading
> > books about how rubidium standards work, etc is fine, but again, you
> > can't home brew the glassware.
> >
> > ---
> > Rick Karlquist
> > N6RK
> >
> > On 2023-06-06 15:39, Tom Van Baak via time-nuts wrote:
> >
> >> Hi Leo,
> >>
> >> That sounds like a fun project. Here are some extremely informative
> resources:
> >>
> >> "Introduction to the Rubidium Frequency Standard"
> >> by Michael Parker, 358 pages
> >> http://www.leapsecond.com/u/parker/ParkerIntroRFS-PPCP.pdf
> >>
> >> "Rubidium Frequency Standard Primer"
> >> by Bill Riley, 163 pages
> >>
> http://www.wriley.com/Rubidium%20Frequency%20Standard%20Primer%20102211.pdf
> >>
> >> "Selection Criteria for Rubidium Frequency Standards"
> >> by Bill Riley, 51 pages
> >>
> http://www.wriley.com/Selection%20Criteria%20for%20Rubidium%20Frequency%20Standards.pdf
> >>
> >> Also read service manuals for commercial Rb products. Didier's site has
> a nice collection. Search by product number (e.g., 5065a) or by title
> (e.g., rubidium):
> >>
> >> http://www.ko4bb.com/getsimple/index.php?id=manuals
> >>
> >> /tvb
> >>
> >> On 6/6/2023 12:25 PM, Leo Ahluwalia via time-nuts wrote:
> >>
> >>> Hello, my name is Leo, and I was wondering about the feasibility of
> >>> creating a simple rubidium atomic clock at home, and good places to
> source
> >>> parts for this sort of project. I was also wondering what instruments
> and
> >>> specialized knowledge would be required depending on how pre-built the
> >>> parts are, for example, the prerequisite knowledge for creating PLL(s)
> for
> >>> both frequency division to provide an output and also to modulate the
> input
> >>> of the microwave oscillator. Any good resources or PDFs would be
> greatly
> >>> appreciated, as I am very new to frequency analysis and phase
> manipulation
> >>> in general. I was also hoping to keep the cost of the project soft-line
> >>> below 500$, though that would be assuming a decent level of precision
> and
> >>> already possessing basic equipment (oscilloscope, multimeter, etc...).
> Safety
> >>> is also a major concern, as I know while the intensity of the EM waves
> >>> involved is low, the power source may or may not be. This is all of
> course
> >>> assuming a basic design, where my assumption is that it will involve
> the
> >>> microwaves being shot at a rubidium vapor cell which is directed
> towards a
> >>> photodetector. This would then be connected up to the PLL and
> circuitry to
> >>> both provide a stable standard while also modulating the microwave
> >>> oscillator to offset any external environmental factors. I don't have a
> >>> clear vision of what would truly be the best design for both
> simplicity and
> >>> cost, though this is what I've found to be a common design in what I've
> >>> looked at online.
> >>>
> >>> Thanks, Leo
> >> _______________________________________________
> >> time-nuts mailing list -- time-nuts at lists.febo.com
> >> To unsubscribe send an email to time-nuts-leave at lists.febo.com
> > _______________________________________________
> > time-nuts mailing list -- time-nuts at lists.febo.com
> > To unsubscribe send an email to time-nuts-leave at lists.febo.com
> _______________________________________________
> time-nuts mailing list -- time-nuts at lists.febo.com
> To unsubscribe send an email to time-nuts-leave at lists.febo.com
>
_______________________________________________
time-nuts mailing list -- time-nuts at lists.febo.com
To unsubscribe send an email to time-nuts-leave at lists.febo.com