Alexander Pummer wrote on Montag, 30. Mai 2016 16:25 >KVG Neckarbischofshofen used to have a crystal in a glass envelope, which was >made just for that purpose it was third overtone crystal ask Bernd if that is >still available, of course you would need a low noise power amplifier to get >that 1W. It is true that 20~30 years ago crystals in glass enclosure used to be under the top performant precision crystals ...until Coldweld technology was "re-discovered" in industry (HP did that before...). Nowadays glass-sealing technology is no longer available (except by a few new manufacturers), as this is a too expensive and delicate process due to the high temperature of melting glass comes very close two the quartz crystal. For a normal transverter type applications there is no need for extra low phase noise. As Rick has pointed out, a "regular" 116 MHz AT 5th overtone crystal in a resistance-weld HC-49/U (4.9 mm pin spacing) or HC-52/U or UM-1 (3.75 mm pin spacing) will do the job perfectly. There are a lot of proven circuits out there, most of them work fine with a crystal adjusted in series resonance. Certainly you can do better with more complex solutions which is like shooting canons to sparrows (as we say here in Germany).
BTW: Alternatively you can use a 116 MHz TCXO (as some of our customers are doing, getting <-155 dBc/Hz @ 10 kHz with a stability of 0.5 ppm over-10~+60°C) - but this is not the place for a commercial, sorry. Have fun Bernd DK1AG _______________________________________________ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
