[DSP-10] Re: DSP-10

[David Garnier]

Mike,

Very interesting stuff!  I am beginning to appreciate all of the work
that goes into the making of a crystal.  Years ago I had a tour of a small
crystal company in Burlington Wisconsin, it was a quick 25 cent tour
because the owner was also a ham, (his company's pride and joy was
a specialized a crystal housed in a octal tube envelope manufactured for
HP but that's another story.

Your last statement suggests one could recondition a crystal element by
cycling the unit through long periods of constant temperature extremes
while cycling the drive to the crystal's.  Correct??? (I take it, in the
case
of temp controlled units one would disable the oven part, right?)  ;-)
Mike, any idea or theory on what�s going with the crystal element during
this cycling period?

Mike I have some other questions about the manufacturing process,
how is the crystal blank tweeked during it�s path through manufacturing,
some sort of etching?  Anything to do with the silver plates deposited on
either side of the blank?  Are crystal blanks ever polarized by a high
voltage in the process of manufacturing, is there a need?  Interesting
stuff,
Mike, thank you.

dave garnier  - wb9own



>
>
> Michael Lodico wrote:
>
>   dave garnier - wb9own something that is not mentioned in those links is
>   component aging.  I worked several years for a company that made OCXO's
>   and did the design work on them which also involved stability over time
>   issues.  These are some of my findings that may help others.
>
>   1)  Aging of the crystal blank is controlled by the cut of the blank,
>   quality of the blank, the blank holder, the plating on the crystal, the
>   back fill gas and Crystal Room aging requirements which can vary from
>   mfg to mfg.
>
>   2)  There are 2 types of electrical aging that goes on with an OCXO.
>   The first is the drive current on the crystal and the second is the
>   parts aging from a current in the support circuit.
>
>   3) The temperature aging process.  The crystal ages at one rate while
>   the components age at a different rate depending on the temperatures
>   involved.
>
>   So with so many variables involved the ideal OCXO would have the
>   crystals aged in the Crystal Room for 30 days using temps going from
>   -20C to 80C or higher with a drive current on them.  The parts for the
>   OCXO would be aged 30 days using the same temp ranges and an electrical
>   current going through each part.  The container for the OCXO would be a
>   vacuum thermos bottle.   Needless to say these are very expensive OCXO's
>
>   and are almost considered standards.
>
>
> Now for what you can do to improve what you may have the best thing
> would be to cycle it for 30 days going from your freezer to an 80C oven
> with a voltage applied several times a day.  After this time frame then
> use a freq. standard to recalibrate your OCXO and you should achieve
> minimal drift and stability over the long term.  I hope this info is of
> some use to people.
>
> Mike Lodico
> K1EG
>
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