One starting point to figure out the 10 years aging can be the datasheet of an OCXO: MTI240: per year, 3.0E-7, in 10 years must be less than 30.0E-7 MTI220: per year, 1.0E-6, in 10 years < 10.0E-6 Bliley NV26R: 17 years, 5.0E-6 OSA8663: per year, 3.0E-8, in 10 years < 30.0E-8
On Fri, Nov 18, 2016 at 11:48 PM, Bob Camp <kb...@n1k.org> wrote: > Hi > > > >> On Nov 18, 2016, at 1:31 PM, Lars Walenius <lars.walen...@hotmail.com> wrote: >> >> Hi Bob (and all others), >> >> I agree to all your points but am curious to your comment: ”that OCXO is >> aging a lot for one that has been on that long”. >> As I have only done this test and seen no other test of OCXO´s powered over >> at least ten years, I have no idea what is reasonable. I also guess I will >> not do another test of an OCXO powered and measured over ten years again. >> >> Could you give some examples what is reasonable for aging after ten years? >> Maybe others have data? I have searched internet and it isn´t easy to find >> long-term data on OCXO’s (at least for me). > > The only people I know of that have the gear and the interest to run a number > of OCXO’s are oscillator manufacturers. They also track parts > in the field by various methods. The data takes real effort to collect and > thus is “part of our IP”. > > Bob > >> >> This oscillator drifted about 60ppm between 1month on to ten years on . Do >> others have figures what is reasonable over this time span? >> >> For point 1: Is it possible from the aging curve to have some ideas what is >> going on?? >> >> Lars >> >> >Från: Bob Camp >> >Skickat: den 17 november 2016 01:03 >> >Hi >> >> >Your data demonstrates a couple of things: >> >> >1) There are a number of different things going on with that OCXO and some >> >things are a lot less predictable than others. >> >2) Oscillators do drop rate while on power. >> >3) Oscillators that age a lot are easier to model (yes, that OCXO is aging >> >a lot for one that has been on that long). >> >> >Bob >> >> >> On Nov 16, 2016, at 2:41 PM, Lars Walenius <lars.walen...@hotmail.com> >> >> wrote: >> >> >> >> FWIW. Between 2001 and 2011 I run a 5MHz OCXO (in a box). It is a 2x3inch >> >> type without EFC marked OFC MC834X4-009W with date code 97. Probably it >> >> was from some base station testing and it had been sitting in my shelf >> >> since 98. The OCXO were battery backed but at two occasions (2004 and >> >> 2007) we had power fails that drained the battery as can be seen in the >> >> graph. >> >> >> >> Just out of curiosity I yesterday put just the first thirty days (like in >> >> the pdf mentioned below) and let Excel calculate the logarithmic >> >> function. If I extrapolate that to 10 years it seems that the drift would >> >> be 6E-13/day but as can be seen in the aging graph it was more like ten >> >> times higher. >> >> >> >> Some days ago I started the OCXO again after it had been on the shelf for >> >> more than 4 years. Enclosed is a graph for the first 7 days. After six >> >> and half days it seems to be a jump of about 1.5E-10 and as I have no >> >> indication of anything else I believe it is from the OCXO. >> >> >> >> /Lars > > _______________________________________________ > 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.
