Tom Van Baak wrote: > > >>I should be able to improve the receiver performance some by ovenizing >>it. I wonder if it would be worth the effort? >> >> > >You can check this with a hair dryer. Measure the effect >of a 10 C rise and then extrapolate back to 0.1 or 0.01C >to see what the result of making an oven would buy you. > > > One problem with that approach is that crystals that are not intended for oven operation are optimized for minimum frequency change over 0-50 or some other "normal" environment temperature range, and at 75 degree C or wherever you are going to run the oven at, the temperature sensitivity might be much greater than around 25 degrees. So even though the oven might reduce the temperature variation by a factor of 10 or better, the overall frequency sensitivity may not improve by the same factor..
Check the following curve http://www.sbtron.co.kr/chinese/technic/frequency_vs_temperature.gif See the curve that is the most flat in the middle and see how rapidly it rises at temperatures above 70 degrees. Then, I am not sure all GPS receivers actually use their internal crystal oscillator in a PLL as the timebase. I have read that some work by removing or adding pulses in a discrete fashion rather than phase locking, and this offers significant jitter, making the 1 PPS only useable to phase lock a reference oscillator with a very long integration period to eliminate the jitter. Now, I can't find the article describing that technique, so it may have been old news. Didier KO4BB _______________________________________________ time-nuts mailing list time-nuts@febo.com https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
