Unruh wrote: > David Lord <[email protected]> writes: > >> David J Taylor wrote: >>> David Lord wrote:
.... > > I get an average of 2usec from pps driving the parallel interrupt ( with > "myown" interupt service daemon). I think much of that is a) ntp's > handling of rate fluctuations, and b)natural variation in the interrupt > handling due to computer issues. My gps 18 has about a 20m run to the > computer, and is simply a "bar wire ( well one of the Cat5e twisted pair > wires) connection. Thanks for that Bill, to both you and David, I'll still make up the pcbs but will first try connecting with straight through cable. .... > Putting in a thermistor on top of the clock crystal and read the > temperature and use it to predict the rate variation. That will probably > give far better results than using a temperature controll. Also using > chrony ( which now has an shm refclock input at least in beta). will > give better results than ntp. From my searches I had opposite impression, that patches to ntp for temperature compensation were good but not anywhere near as good as keeping crystal at constant temperature. Add to that a pps source probably takes system clocks largely out of the equation. I'm very happy to give chrony another try. I used it for a few years without problems when on dialup. I'm thinking of notebook rather than servers but I'd be happy to try on one of servers (webserver uses ntpd but has chrony-1.20nb3 which I guess is old). David _______________________________________________ questions mailing list [email protected] https://lists.ntp.org/mailman/listinfo/questions
