Interferogram showing vibration nodes etc for quartz ring resonator frequency
standard attached.
Bruce
> On 01 March 2020 at 14:27 Bob kb8tq <[email protected]> wrote:
>
>
> Hi
>
> It’s also the size of the 2.5 MHz 5th’s and similar parts made “way back”.
> They went into glass packages
> the size of door knobs. Packaging / design / mounting / processing has
> changed a lot since then.
>
> Bob
>
> > On Feb 29, 2020, at 7:41 PM, John Moran, Scawby Design
> > <[email protected]> wrote:
> >
> > Wow, that provoked an interesting discussion!
> >
> > Thanks for all the information and references to further information - it
> > should keep me quiet for a while.
> >
> > Interestingly 50mm diameter was about the diameter of the crystals used by
> > the British Post Office in the early days for generating a master
> > oscillator. It wasn't ground into a plano-convex lens but as a ring and was
> > about 10mm thick. Like the old WW2 crystals the electrodes weren't plated
> > but just contact rings. I have no idea what frequency they were ... by the
> > time that I realised they were scrapping all this kit it was gone and I
> > only managed to salvage two GPO Type 36 master 1S pendulums from a dumpster!
> >
> > Thanks again for all the feedback.
> >
> > John
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>
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