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@lists.febo.com To unsubscribe, go to http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com and follow the instructions there.
