Another fascinating tuning-fork standard was used together with a Synchronome to govern the timing of pulses of Morse code on undersea telegraph cables in the British empire’s globe-girdling telegraph network. Timing was derived electromagnetically from incoming Morse code signals (a bi-polar signal where one polarity represented a dit and the other a dah, but both dit and dah were of equal length) to set the master at each downstream relay/switching station on a cable route.
In essence, brass, mahogany and electromagnetics were use to perform all the functions done today on fiber optic cables: signal generation, multiplexing, regeneration, and timing recovery… not to mention encoding & decoding plus printing. One can see a working example at the Museum of Undersea Telegraphy in Porth Curno, Cornwall — a museum well worth the detour to Land’s End. — Eric > On 2017 Dec 09, at 10:11 , Don <[email protected]> wrote: > > Thank you, Pete. -Don > > ========================== > > > > > On Sat, 2017-12-09 at 05:57 -0800, Pete Lancashire wrote: >> Here's a look at a 723-C (1,000 cps) and how its power supply cap was >> handled and a good look inside >> >> https://www.eevblog.com/forum/reviews/vintage-teardown-general-radio- >> 723-c-vacuum-tube-tuning-fork/ >> >> >> The GR Experimenter >> >> http://www.americanradiohistory.com/Archive-General-Radio/GR%20Exp%20 >> 1941_10.pdf >> >> There is another Experimenter that goes into how the tuningfork was >> made >> but can't find it >> >> -pete >> >> On Sat, Dec 9, 2017 at 5:18 AM, Don <[email protected]> wrote: >> >>> >>>> >>>> I was fortunate to find a vintage, General Radio (GR) Model 723D >>>> Precision Oscillator (tuning fork). >>>> >>>> The exceptional wooden case is as 'exciting' to look at as is the >>>> mechanical tuning fork inside (400Hz). >>>> >>>> As it is ac powered, I'll need to recap it before I turn it on. >>>> Then, we can test for accuracy! (sic). >>>> >>>> A real class-act, 'time-nut' oscillator from the last century, >>>> predating crystals. >>>> >>>> Don >>>> >>>> Don Lewis _______________________________________________ time-nuts mailing list -- [email protected] To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
