I seem to recall that crystals for frequency control (on a commercial basis) were sort of a post WW2 thing (partly because of developments in piezo hydrophones for sonar)
Crystals for radios were well established pre-WWII. There was an FCS paper ~30 years ago about the WWII quartz shortage and the research to find alternatives to quartz (which they didn't know how to grow synthetically yet). Spoiler alert: there is nothing else like quartz!. Novice hams routinely used war surplus crystals (FT-243?) after the war. I had some at 3.7 and 7.15 MHz fundamental and they oscillated fine with receiving tubes, circa 1965. There was some standard military crystal test set from the war that was always referenced in crystal specs in those days. The test set was in essence a "golden" oscillator. Rick N6RK _______________________________________________ time-nuts mailing list -- [email protected] To unsubscribe, go to http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com and follow the instructions there.
