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. "Burt I. Weiner" <[email protected]> wrote: >Brian, > >I remember grinding FT-243 crystals. I had a TV set safety glass >about 18" square and about 1/4" thick. That and some Comet type >cleanser mixed with water to make a thin paste would work wonders. I >was taught to put my finger on the corners and grind an equal amount >on the 8 corners (4 on each side) so as not to remove the bevel of >the quartz. Once I applied this lesson I was able to grind crystals >that were more stable and more active. When I over-leaded them I was >generally able to remove the lead using alcohol. I've still got the >old TV safety glass although it has an area near one corner that is >very opaque do to all the grinding that was done in that area. Those >were fun days! > >Burt, K6OQK > > >>From: Brian Alsop <[email protected]> >> >>Reminds me of the FT-243 xtal controlled transmitter Novice days. >Xtals >>of the frequency you wanted were hard to come by. We would grind >xtals >>a bit on a bed of very fine abrasive to raise their frequency. >> >>The other trick was taking a pencil and adding graphite to the xtal >>faces to lower it's frequency. You couldn't add too much or it would >>stop oscillating-- forever. Never did understand the forever part. >>Removing the graphite didn't bring it back to life. >> >>Brian >>K3KO > >Burt I. Weiner Associates >Broadcast Technical Services >Glendale, California U.S.A. >[email protected] >www.biwa.cc >K6OQK > >_______________________________________________ >time-nuts mailing list -- [email protected] >To unsubscribe, go to >https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts >and follow the instructions there. -- Sent from my Android device with K-9 Mail. Please excuse my brevity. _______________________________________________ time-nuts mailing list -- [email protected] To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
