connie.marshall@suddenlink.net said: > www.k5cm.com/soundcard.htm Nice, thanks. >From there: > Sound card drift over this four hour period is about 250 micro Hertz. > The temp in the shack was going up during the measurement period. > Unfortunately I did not track the exact temp rise, but was about > around 4 to 6 degrees F. 250 micro Hz relative to 1000 Hz is 1/4 ppm. My memory is that junk PC crystals are ballpark of 1 ppm/degree. (That's probably per degree C rather than F, but that's only a factor of 2.) So 1/4 ppm for 4 degrees is better than I would have guessed. -- These are my opinions, not necessarily my employer's. I hate spam.

You know, I probably need to run the test again and do a better job of tracking room temp. My thermometer is high up on the wall in the shack. The computer sets under the bench in a corner. It does represent a typical afternoon in my shack however. 73, Connie K5CM -----Original Message----- From: time-nuts-bounces@febo.com [mailto:time-nuts-bounces@febo.com]On Behalf Of Hal Murray Sent: Wednesday, June 03, 2009 12:24 PM To: Discussion of precise time and frequency measurement Subject: Re: [time-nuts] Sound Cards for locking to GPSDO 10 MHz references connie.marshall@suddenlink.net said: > www.k5cm.com/soundcard.htm Nice, thanks. >From there: > Sound card drift over this four hour period is about 250 micro Hertz. > The temp in the shack was going up during the measurement period. > Unfortunately I did not track the exact temp rise, but was about > around 4 to 6 degrees F. 250 micro Hz relative to 1000 Hz is 1/4 ppm. My memory is that junk PC crystals are ballpark of 1 ppm/degree. (That's probably per degree C rather than F, but that's only a factor of 2.) So 1/4 ppm for 4 degrees is better than I would have guessed. -- These are my opinions, not necessarily my employer's. I hate spam. _______________________________________________ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.