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 <[email protected]> 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 > >> On Mon, Nov 7, 2016 at 10:34 AM, Scott Stobbe <[email protected]> >> wrote: > >> Here is a sample data point taken from http://tycho.usno.navy.mil/ptt >> i/1987papers/Vol%2019_16.pdf; the first that showed up on a google search. >> >> Year Aging [PPB] dF/dt [PPT/Day] >> 1 180.51 63.884 >> 2 196.65 31.93 >> 5 218 12.769 >> 9 231.69 7.0934 >> 10 234.15 6.384 >> 25 255.5 2.5535 >> >> If you have a set of coefficients you believe to be representative of your >> OCXO, we can give those a go. >> >> > > <Aging per day OFC x834 2001-2011.PNG><Drift OCXO OFC x834 2001 30 first > days.PNG><Drift OCXO OFC x834 2001-2011.PNG><Drift OCXO OFC x834 > 2016.PNG>_______________________________________________ > 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.
