[time-nuts] Glass Envelope Quartz Crystals

Dave Brown tractorb at ihug.co.nz
Wed Feb 3 14:36:09 EST 2016


And many of these glass envelope crystals were made on very low frequencies- 
I have  several below 20 kHz and one as low as 3 kHz in a B7G based envelope 
that is 4 inches long.
http://homepages.ihug.co.nz/~tractorb/3k1.JPG

DaveB, NZ

----- Original Message ----- 
From: "Alan Melia" <alan.melia at btinternet.com>
To: "Discussion of precise time and frequency measurement" 
<time-nuts at febo.com>
Sent: Thursday, February 04, 2016 6:30 AM
Subject: Re: [time-nuts] Glass Envelope Quartz Crystals


>I think it was unlikely that that it was made "just to see where it would
> come out" That is a flexural bar possibly an NT cut. 100KHz standards were
> commonly made in this format.
> The British GPO had a factory at Mill Hill in N. London making these in
> tube-like (valve in UK) enclosures, IO GT and B7G. I have a number of unit
> saved from the dumpster (skip in the UK).when the unit closed in the early
> 60s. Remember there was a surge in telephones in this era and many of 
> these
> frequencies were for FDM carriers on trunk sytems. This is 
> pre-synthersiser.
>
> Also many special quality tubes were made for VHF in B7G with two or three 
> inch wires instead of pins to reduce the socket parasitics. so these were 
> probably still around in Russian factories to produce  components for the 
> "Foxbat" etc.
>
> Alan
> G3NYK
>
>
> ----- Original Message ----- 
> From: "Philip Gladstone" <pjsg-timenuts at nospam.gladstonefamily.net>
> To: <time-nuts at febo.com>
> Sent: Wednesday, February 03, 2016 1:21 PM
> Subject: Re: [time-nuts] Glass Envelope Quartz Crystals
>
>
>>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 <jn6wfo at gmail.com> 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 <kb8tq at n1k.org>
>>>>>>> Data: 02/02/2016 13.15
>>>>>>> A: "Discussion of precise time and frequency
>>>>>>> measurement"<time-nuts at febo.com>
>>>>>>> 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 <watsondaniel3 at gmail.com>
>>>>>>>> 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.
>>>>>>
>>
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