I am attaching a file showing the schematic for the trap used in a Colpitts oscillator which will look like 58pF at 5MHz and will be inductive at 5.5MHz. So something like this can be used in place of a pair of one of the split capacitors at ~56pF loading the crystal.
Jerry N9XR On Sat, Jul 18, 2015 at 11:59 AM, Magnus Danielson < [email protected]> wrote: > Dear Ulrich, > > Now you taught me something useful, that the SC-cut has inherent less > noise than AT-cut. Many thanks. > > Indeed, measuring below 1 Hz starts to be challenging as environmental > aspects chimes in. I assume you ovenize your crystals, to make use of the > turn-over point. > > Even for ovens, (wind)shielding to reduce thermal stress turns out to be > helpful. Some toss their oscillators into thermal flasks too. As always, a > myriad off issues creep up as you push the noise down and want to verify > it. Thermal mass has proven useful in many ways. There was a nice paper > from NIST where they used water-bottles to stabilize WWVB. > > Cheers, > Magnus > > On 07/18/2015 11:52 AM, KA2WEU--- via time-nuts wrote: > >> Good morning, >> >> the AT Cut is inherently noisier then the SC cut but the SC has some >> spurious resonances modes. Measurements below 1 Hz are very tricky as the >> oscillator must be (more or less) insulated from hum, infrared (heater) >> . Here I >> am still struggling . >> >> Ulrich N1UL >> >> >> In a message dated 7/17/2015 9:59:55 P.M. Eastern Daylight Time, >> [email protected] writes: >> >> He doesn't mention that that crystal is used in New Horizons: >> http://www.bliley.com/products/crystals-precision-standard/vacuum-sealed/ >> >> Nice. I have a similar crystal from Valpey-Fischer, 5 MHz 5th overtone >> AT-cut (as opposed to your 3rd overtone SC-cut). I would be interested >> in what you would use for an oscillator circuit. >> >> David N1HAC >> >> >> On 7/17/15 4:27 PM, paul swed wrote: >> >>> Ulrich, >>> Nice picture. What are you doing with the crystal? I have several older >>> crystals that are nice but have never done anything with them. >>> Regards >>> Paul >>> WB8TSL >>> >>> On Thu, Jul 16, 2015 at 6:02 PM, KA2WEU--- via time-nuts >>> >> <[email protected] >> >>> wrote: >>>> >>>> I am working with this ...... amazing device, Ulrich N1UL >>>> _______________________________________________ >>>> 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. >>>> >>>> _______________________________________________ >>> 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. >>> >> >> _______________________________________________ >> 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. >> >> _______________________________________________ >> 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. >> >> _______________________________________________ > 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. >
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