Very interesting! Hazarding a guess.... higher end of a NT-cut? Looks much like the third from the right here: http://www.pbgquartz.com/www.pbgquartz.com/images/foto1.jpg
Some crystals in this range were used as filters or LO's in telecom SSB-type channel banks (I think that's what the vendor who made that photo, used to specialize in) but I don't know if those were generally NT cut or what. Tim N3QE On Wed, Feb 3, 2016 at 8:21 AM, Philip Gladstone < [email protected]> wrote: > I dug around in my junk box, and found this: > > > https://plus.google.com/+PhilipGladstone/posts/JBNLMSq2rsE?pid=6247050011623528018&oid=115465617973526125523 > > This is (according to the markings) a 71.137 kHz crystal made in 1948. I > suspect that they just measured the crystal after manufacture rather than > actually trying to make a 71137Hz crystal.... > > After this discussion, I'm feeling the need to fire it up and see whether > it still runs, and what the aging has done to the frequency.... > > Philip > > > On 03/02/2016 07:11, Bob Camp wrote: > >> Hi >> >> There is actually a range of crystals shown in the pictures. The gold >> plated 5 MHz >> crystal is probably an overtone part. It could be fairly precise. The 25 >> MHz part is >> plated with something like silver. It probably is a *much* lower >> precision part. There >> likely are long stories that explain just why this or that package got >> used in this >> or that application. >> >> Bob >> >> On Feb 2, 2016, at 10:04 PM, Jeremy Nichols <[email protected]> wrote: >>> >>> The OP's picture looks very much like the crystals that HP's "Frequency >>> and Time" division in Santa Clara (02 was their division number) used to >>> manufacture back in the 1970s. My picture shows a 1 MHz crystal that HP >>> used in the predecessor to the HP-105A (perhaps the 101A). >>> >>> Jeremy >>> >>> >>> http://s323.photobucket.com/user/Jeremy5848/media/Miscellaneous/Crystal_1140587_zps0jxjpoal.jpg.html >>> >>> >>> >>> On 2/2/2016 12:24 PM, Don Latham wrote: >>> >>>> You have it right, iovane. At the least, they should be protected from >>>> light, >>>> thermal radiation, and emf. Won'drous things will happen if the >>>> crystal and >>>> its structure are subjected to radiation through the glass. I'd suggest >>>> a foam >>>> wrap in a tin can as a minimum. Put the oscillator cat in there too. >>>> Don >>>> >>>> iovane--- via time-nuts >>>> >>>>> I think that these crystals were designed to be placed in an oven, >>>>> which >>>>> worked >>>>> as a shield too. I have a similar crystal made by Racal in the 60's, >>>>> and in my >>>>> case it is fitted with the classic octal tube-type plug. It was housed >>>>> (still >>>>> is) in a heavy massive shimmering chrome-plated cylindrical brass >>>>> enclosure, a >>>>> beauty to see, It was the timebase of a tube-type synthesizer with >>>>> lots of >>>>> tubes. Themperature control was achieved by means of a mercury >>>>> thermometer in >>>>> which mercury actuated a contact when reaching a wire crossing the >>>>> capillary >>>>> tube. >>>>> >>>>> Antonio I8IOV >>>>> >>>>> Da: Bob Camp <[email protected]> >>>>>> Data: 02/02/2016 13.15 >>>>>> A: "Discussion of precise time and frequency measurement"< >>>>>> [email protected]> >>>>>> Ogg: Re: [time-nuts] Glass Envelope Quartz Crystals >>>>>> >>>>>> Hi >>>>>> >>>>>> Since the 25 MHz crystal has already been soldered into a circuit, >>>>>> putting it >>>>>> >>>>> in a >>>>> >>>>>> socket is probably not a real good idea. It’s also a leaded part. >>>>>> Even with >>>>>> >>>>> fat pins >>>>> >>>>>> sockets can be an issue. With wire leads, you are asking for trouble. >>>>>> >>>>>> Functionally, there is little there is little difference between a >>>>>> glass >>>>>> >>>>> package crystal >>>>> >>>>>> and a metal package. About the only real one is the obvious - one has >>>>>> a metal >>>>>> >>>>> shield >>>>> >>>>>> you can (but sometimes don’t) ground. >>>>>> >>>>>> Bob >>>>>> >>>>>> >>>>>> On Feb 1, 2016, at 9:58 PM, Daniel Watson <[email protected]> >>>>>>> wrote: >>>>>>> >>>>>>> Hi, >>>>>>> >>>>>>> I purchased a pair of interesting glass envelope crystals for a >>>>>>> project. >>>>>>> Here are some pictures: >>>>>>> >>>>>>> >>>>>>> http://syncchannel.blogspot.com/2016/02/glass-envelope-quartz-crystals.html >>>>>>> >>>>>>> Does anyone have an idea about what mount/socket I should buy for >>>>>>> these? I >>>>>>> read a previous thread on the list about Bliley crystals using a B7G >>>>>>> mount, >>>>>>> but I'm not sure if that type might work here. >>>>>>> >>>>>>> Also, when building up a circuit to make these oscillate, are there >>>>>>> any >>>>>>> specific differences about crystals in this package that I should >>>>>>> keep in >>>>>>> mind? >>>>>>> >>>>>>> >>>>>>> Thanks much, >>>>>>> >>>>>>> Dan W. >>>>>>> >>>>>> >>>>> > _______________________________________________ > 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. > _______________________________________________ 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.
