[ARC5] Crystal aging

[Dennis Monticelli]

Hello Bruce,

It's great to meet someone that was right in the middle of that amazing
effort to literally create a broad crystal manufacturing effort overnight.

Yes, the pressure on the blank, the exact placement of the pressure, the
air gaps, etc all matter.  The small mass of the plated contacts on modern
crystals are used to fine tune the frequency and these regions can display
aging characteristics too.  The well-etched defect-free crystal mand-made
quartz blank all by itself is extremely stable with time.  It only needs
temp correction and/or temp stabilization.

Perhaps you could share more stories with us about those crystals in our
past.

Dennis AE6C

On Fri, Mar 15, 2013 at 9:47 AM, Bruce Long <coolbrucelong at yahoo.com> wrote:

> Sorry Kennth for sending this email originally just to you instead of the
> group   bruce
>
>
>
> with respect to HF  I discovered to my surprise some small bottle rust
> removing potions available at the big orange box are actually dilute HF
> solutions.  They work really well for me.
>
> I am also very happy to
>  see this discussion of the important of WW2 quartz crystal technology-
> having been previously employed at Piezo Crystal Company, McCoy
> electronics and Bliely- the latter as a consultant.
>
> The huge
> expansion of the quartz crystal industry in the USA was in my opinion a
> very important aspect of the American war effort and is not widely
> understood or recognized.  IIRC the war time expansion when from fewer
> than 10 very small pre-war crystal companies that catered to the amateur
>  and custom experimental market to well over 300 companies at the peak
> manufacturing what was at the time an extremely high tech,
>  precision product.
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