Hoi Gerhard! On Wed, 26 Feb 2020 01:42:11 +0100 Gerhard Hoffmann via time-nuts <time-nuts@lists.febo.com> wrote:
> Pics are there: > > < > https://www.flickr.com/photos/137684711@N07/49585174873/in/album-72157662535945536/ > > > Nice pictures! Thanks! Do you know what the two coils/transformers that were glued to the outside of the inner oven were for? > But I could not see anything at 1 or 1.6666 MHz, so it should be a > fundamental crystal? Judging from the specs, very unlikely. The short-term and long-term stability are consistent with what I expect of an 3rd overtone 5MHz SC cut crystal. The lower Q of a fundamental mode crystal would result in a higher close in phase noise and the thinner plate would lead to a higher aging rate at tau of one day. I can see two reasons for you to not see the fundamental mode: Either your measurement setup was not done properly to measure quartz crystals (see Bob's comment on impedance) or they manufactured the crystal for low fundamental mode. Bernd Neubig has written a few documents on how to measure crystals properly, which should be available from Axtal's website, if I'm not mistaken. Attila Kinali -- In science if you know what you are doing you should not be doing it. In engineering if you do not know what you are doing you should not be doing it. -- Richard W. Hamming, The Art of Doing Science and Engineering _______________________________________________ time-nuts mailing list -- time-nuts@lists.febo.com To unsubscribe, go to http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com and follow the instructions there.