A problem I've seen when using the hermetic sealed soldered version of the 10811 from a dual oven unit, is when the case is sealed the osc makes a good barometer because of changes in its case due to barometric changes. A 1 inch difference (such as 30 to 29) caused something on the order of 1e-11 freg change. To see the effect just need to put a little pressure on the case So now I'm trying to determine which is worse, leaving the freq adj screw tight and sealed or leaking a little, inside a box containing desiccant.
ws ****************** > > Heating up a space does not change the absolute humidity AFAIK. > It only changes the relative humidity. We did tests where we > "sealed" a 10811 inside a box that was held together with so-called > "hermetic" epoxy. We put it in an environmental chamber at a > constant temperature and constant low humidity and let it stabilize. > We then increased the humidity to something like 80%, > while holding the temperature constant. Within > minutes the frequency changed more than the spec for the entire > temperature range. Therefore, you should do your experiment with > the hermetic version of the 10811. The hermetic version is soldered > shut, rather than using epoxy, which turns out not to be hermetic, > no matter what they claim. > > Rick Karlquist > _______________________________________________ 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.
