[time-nuts] Re Looking for QST Jan 1990 article on Crystals

Cornell cornell at charter.net
Mon Dec 25 01:26:05 EST 2006


A couple of ideas on crystal testing which I have found to be a quick and
dirty way to check crystal activity. There are probably many other ways, but
these work for me. These work out of circuit, but I doubt they would be any
good testing in circuit. Either device works with regular or overtone
crystals.

1. ARRL's Radio Amateur Handbook 1975 page 523. I constructed this tester
into a mini box pretty much per the schematic. I ran sockets for crystals to
the panel such that I can quickly change crystals, and also used sockets for
the transistors. It will work on PNP, NPN, MosFets, and Jfets. The meter
gives an indication of activity. A nine volt battery will run this thing for
years if S2 is a spring loaded push button. This project was published by
ARRL in several other books.

2. The Heathkit HD-1250 Grid Dip Oscillator (should you have one) also can
be used to check crystal activity. The inductor jack is on the back panel.
Prepare a phone plug with two leads, each lead with a small alligator clip.
Insert the phone plug into the inductor jack. To check activity attach the
clips to the crystal pins and turn on the meter. Again, a meter deflection
will indicate crystal activity. Tuning the variable capacitor has no effect
on the meter reading.

If you want, I would be glad to take pix of either one, scan the article and
e-mail to you, etc. Just let me know.

Max Cornell K0MC
cornell at charter.net




>-----Original Message-----
>From: time-nuts-bounces at febo.com [mailto:time-nuts-bounces at febo.com] On
>Behalf Of Brooke Clarke
>Sent: Wednesday, December 20, 2006 5:15 PM
>To: Discussion of precise time and frequency measurement
>Subject: [time-nuts] Looking for QST Jan 1990 Article on Crystal S,Q & R
>testing By DeMaw
>
>Hi:
>
>I'm looking for  the subject article on crystal testing, or any other
>articles on testing crystals.
>This is more related to knowing if a given crystal is alive than
>characterizing it, i.e. a Crystal Activity Meter type thing.
>
>Have Fun,
>
>Brooke Clarke





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