Poseidon Scientific Instruments (acquired by Raytheon) make a room temperature 10.24GHz Sapphire loaded cavity oscillator with a low PN floor: https://www.rdi.uwa.edu.au/__data/assets/pdf_file/0012/3447669/Raytheon-TechnologyToday-20141-Extract.pdf
Bruce > On 02 April 2021 at 05:06 Chris Caudle <6807.ch...@pop.powweb.com> wrote: > > > On 2021-03-31 14:27, Richard (Rick) Karlquist wrote: > > When I left Keysight in 2014, they were still trying to solve the > > microphonic problem in their sapphire resonator oscillator. Also, > > it is still necessary to lock the oscillator to a 5 or 10 MHz > > OCXO. The oscillator is tuned by varying its oven temperature > > set ppoint. > > What kind of oven temperature range? I thought sapphire oscillator was > pretty much synonymous with "cryogenic sapphire oscillator." I found a > paper which described sapphire as a "low loss material with loss tangent > of 5×10^−6 at room temperature, 2×10^−8 at 77 K and 7×10^−10 at 4 K > giving Q-values of more than >10^7 at low temperatures." > > That paper seemed to be describing some kind of temperature compensation > they had developed to reduce the temperature sensitivity of 10ppm/K and > also move the turnover point from 77K to 92K. 92K isn't exactly what I > think of when I hear "oven" so presumably there is some mode that works > at around 300K that I didn't find discussed yet. > > -- > Chris Caudle > _______________________________________________ > time-nuts mailing list -- time-nuts@lists.febo.com -- To unsubscribe send an > email to time-nuts-le...@lists.febo.com > To unsubscribe, go to and follow the instructions there. _______________________________________________ time-nuts mailing list -- time-nuts@lists.febo.com -- To unsubscribe send an email to time-nuts-le...@lists.febo.com To unsubscribe, go to and follow the instructions there.