Hi Rick: Thanks for pointing that out. Maybe the factor is air density. I know air density was the thing we used to monitor to jet the carbs in racing cars. It was better than using a barometer and/or thermometer.
Have Fun, Brooke Clarke -- w/Java http://www.PRC68.com w/o Java http://www.pacificsites.com/~brooke/PRC68COM.shtml http://www.precisionclock.com Rick Karlquist wrote: >You must be kidding. No way are Zip Lok bags hermetic. >Water vapor will diffuse right through. (Note that waterproof >does not equal hermetic). > >Rick N6RK > > >Brooke Clarke wrote: > > >>HI Rick: >> >>For humidity control in other applications I have used Zip-Lok bags. >>How about putting the 10811 in a Zip-Lok bag and run the wires through a >>hole that gets epoxy sealed? Some desiccant would lower the humidity if >>that is an advantage. >> >>Have Fun, >> >>Brooke Clarke >> >>-- >>w/Java http://www.PRC68.com >>w/o Java http://www.pacificsites.com/~brooke/PRC68COM.shtml >>http://www.precisionclock.com >> >> >> >>Richard (Rick) Karlquist wrote: >> >> >> >>>>Given that HP's engineers have done such a good job with >>>>the oven and oscillator design, is there anything to be gained >>>>by adding extra thermal insulation (lagging)? How much >>>> >>>> >>>> >>>> >>>Not a good idea. The best thing you could do to improve >>>temp stability of a 10811 is to tweak the resistors that >>>proportion the power between the two heater transistors. >>>At some ratio, the thermal gain will peak at over 1000 >>>typically. If you just take pot luck, you would be lucky >>>to do 100. You are still limited by the tempco of the >>>electronics, no matter what thermal gain you achieve at >>>the crystal. >>> >>>You should also be aware that the 10811 is fairly humidity >>>sensitive, which can seem like temperature sensitivity >>>if the humidity and temperature change together. >>> >>>The HP E1938 was a much better design in terms of environmental >>>insensitivity, but that didn't help much because the >>>ultimate stability was limited by crystal frequency jumps, >>>which didn't seem so bad with the 10811 due to the large >>>environment errors in it. In the E1938 they stuck out like >>>a sore thumb. >>> >>>Rick Karlquist N6RK >>> >>> >>> >>> _______________________________________________ time-nuts mailing list time-nuts@febo.com https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts