[time-nuts] Grinding crystals...

[Ed Palmer]

I have a copy of  " Understanding Amateur Radio" published by the ARRL 
in 1963.  One of the appendixes is titled "Changing Crystal Frequencies" 
and talks about grinding crystals from FT-243 holders.

Just google on < "ft-243" crystal grinding > and you'll find lots of web 
pages and at least one YouTube hit.

Ed

On 6/20/2013 8:06 PM, Hal Murray wrote:
> nuts at lazygranch.com said:
>> A common scheme in metal deposition measurement is to measure the frequency
>> of a crystal prior to starting the deposition process, then monitoring the
>> frequency shift of the crystal as the metal is sputtered.
>> I was told crystals are tuned this way at the factory, but don't know this
>> for a fact.
> I don't have any good references, but I've seen that story several times, and
> at least some of them were credible enough so that my opinion changed from
> sounds-good to really-works.
>
> -------
>
> Many years ago (50+), I remember stories of grinding or leading crystals.  I
> remember taking one apart.  It was only a few screws.  Does anybody have an
> ARRL handbook from that era?
>
> Does anybody have any estimates on what the performance of a hermetically
> sealed crystal is compared to an old non-sealed mounting?  (Do they still
> make the old non-sealed mounting?)
>
> I also remember getting several crystals cut to order, one each for me and a
> few friends.  That was through the local radio/TV fixit parts store, a block
> or two from the high school.
>
>