I am not sure if anyone else mentioned this, Placing the parts against the oscillator with a little thermal epoxy under a small piece of foam so they are at least partially "ovenized" should really help.
Thomas Knox > From: li...@rtty.us > Date: Fri, 31 Jan 2014 22:36:46 -0500 > To: lajeune...@mail.com; time-nuts@febo.com > Subject: Re: [time-nuts] EFC divider resistors > > Hi > > If you attenuate the DAC 100:1 to 1000:1 before it hits the OCXO, the DAC > does not matter much. That may sound like a crazy ratio, but it is indeed > possible with some of these OCXO EFC ranges. They can have a *lot* of swing. > > The reference is an LTZ1000, they run about $50 in single piece lots. You can > get resistors that run below 1 ppm tracking without a whole lot of effort > > Bob > > On Jan 31, 2014, at 8:38 PM, Robert LaJeunesse <rlajeune...@sbcglobal.net> > wrote: > > > Must be military prices. If using 5 PPM resistors in the build a reference > > much better than that isn't needed, especially if the temperature is > > somewhat controlled, like time nuts do. A commercial 3 PPM/C part, the > > LM4140A, is $4.54 each in singles. At 2.2uV p-p it's reasonably quiet as > > well. > > > > Considering stability influences, what provides the DAC reference? That's > > rather important as well. > > > > Bob LaJeunesse > > > > I'd also note the 2 PPM ratio tracking dividers, the MAX549x series, can be > > had in the $3.49 range, also not all that expensive. > > > > > > > >> ________________________________ > >> From: Bob Camp <li...@rtty.us> > >> To: Bob Stewart <b...@evoria.net>; Discussion of precise time and > >> frequency measurement <time-nuts@febo.com> > >> Sent: Friday, January 31, 2014 7:17 PM > >> Subject: Re: [time-nuts] EFC divider resistors > >> > >> > >> > >> ... A good voltage reference will set you back about $50 or so. > >> > > _______________________________________________ > > 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.
