I was hoping to measure the ppm error of a Raspberry Pi's crystal using an NTP client running on the Pi itself. The NTP client reports a ppm correction that I find to be consistently (measurements performed over several days) off by about 10 ppm compared to what I measure using my GPS calibrated frequency counter (HP5328). Specifically, the Pi reports a required ppm correction of -33 ppm whereas I consistently measure a required correction of -43 ppm on my frequency counter.
Any ideas on where I can look to track down the discrepancy? Perhaps the timers on the RPi are configured incorrectly in the kernel? Or is this the best I can expect from NTP? I would understand the situation if the NTP reported correction drifted above and below -43ppm, but it seldom departs from -33ppm by more than 1 or 2 ppm... Thanks, James P.S. I apologize if this isn't time-nutty enough :) I only need about 1ppm accuracy in my corrections :) -- *Integrity is a binary state - either you have it or you don’t.* - John Doerr _______________________________________________ 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.
