[time-nuts] Glass Envelope Quartz Crystals

[Don Latham]

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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-- 
Felix qui potuit rerum cognoscere causas.
Lucky is he who has been able to understand the causes of things.
Virgil
-------------------------------
"Noli sinere nothos te opprimere"

Dr. Don Latham, AJ7LL
Six Mile Systems LLC, 17850 Six Mile Road
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