Yes, all about experience , Ulrich In a message dated 7/19/2015 9:46:17 A.M. Eastern Daylight Time, kb...@n1k.org writes:
Hi There are an enormous number of variations on the basic SC trap. Most of what drives one to be “best” is the component selection process. If a coil above X uh simply will not fit, time for a new circuit …. Bob > On Jul 19, 2015, at 12:53 AM, jerry shirᴀr <radio.n...@gmail.com> wrote: > > 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 < > mag...@rubidium.dyndns.org> 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, >>> n1...@dartmouth.edu 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 >>>> >>> <time-nuts@febo.com >>> >>>> wrote: >>>>> >>>>> I am working with this ...... amazing device, Ulrich N1UL >>>>> _______________________________________________ >>>>> 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. >>>>> >>>>> _______________________________________________ >>>> 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. >>>> >>> >>> _______________________________________________ >>> 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. >>> >>> _______________________________________________ >>> 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. >>> >>> _______________________________________________ >> 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. >> > <5MHz SC trap.png>_______________________________________________ > 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. _______________________________________________ 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. _______________________________________________ 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.