Rick- You've peaked my interest. Has anyone ever collected any data on 10811 frequency vs. humidity or dew point?
-Brian, WA1ZMS -----Original Message----- From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] Behalf Of Richard (Rick) Karlquist Sent: Tuesday, June 20, 2006 1:03 AM To: Discussion of precise time and frequency measurement Subject: Re: [time-nuts] 10811 Extra Lagging etc > 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 _______________________________________________ time-nuts mailing list time-nuts@febo.com https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts