[time-nuts] What is the BEST crystal?

[Bob kb8tq]

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 <john at scawbydesign.co.uk> 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
> _______________________________________________
> time-nuts mailing list -- time-nuts at lists.febo.com
> To unsubscribe, go to http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com
> and follow the instructions there.