Hi Bob, I was afraid that the answer should be like this (smile). One paper from MTI that probably confirms that aging prediction is difficult: http://www.mti-milliren.com/MTIPapers/Ext_Aging_Perf_Results.pdf Lars From: Bob Camp<mailto:kb8tq@n1k.org> Sent: den 19 november 2016 00:23 Hi > On Nov 18, 2016, at 1:31 PM, Lars Walenius <lars.walenius@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