Hi! Thank you for your input.
Yes, I've set minpoll and maxpoll to 4 yet the system corrects the offset slowly during the calibration interval that starts I believe at 8 seconds (2^3) and stops at 256 seconds (2^8) even though I've set min and maxpoll. Even considering this situation I am going crazy with the Trimble Acutime Gold I installed on my roof. I connected the port A to a RS422-to-RS232 converter. The PPS+ signal is directly connected to the DCD pin of this RS232 port. The port B is also connected to a RS422-to-RS232 converter and I occasionally connect a Windows computer to check the status of the antenna. I've reconfigured the antenna to output only NMEA sentences (and I also use the PPS) and NTP works fine but suddenly without any explanation the NTP process stops receiving information from the receiver. I really don't understand what's happening here as the receiver is on the roof and sees plenty of satellites: 56427 70907.634 127.127.20.0 $GPGGA,194147.0,4055.227,N,00829.618,W,1,07,1.14,00264,M,051,M,,*48 56427 70923.635 127.127.20.0 $GPGGA,194203.0,4055.227,N,00829.617,W,1,07,1.14,00262,M,051,M,,*42 56427 70939.634 127.127.20.0 $GPGGA,194219.0,4055.226,N,00829.616,W,1,06,1.47,00258,M,051,M,,*47 56427 70955.635 127.127.20.0 $GPGGA,194235.0,4055.226,N,00829.615,W,1,07,1.14,00251,M,051,M,,*44 56427 70971.634 127.127.20.0 $GPGGA,194251.0,4055.227,N,00829.616,W,1,07,1.13,00255,M,051,M,,*47 Can anyone help me please? Cheers, Miguel On 15 May 2013 18:33, Chris Albertson <[email protected]> wrote: > i've seen that myself, NTP's compensation can almost be used as a way to > measure room temperature. You can see the AC cycles. For this reason I > keep the NTP server in a walk in closet that lacks heating duct. The room > temp cycles slowly. > > I've also read but can't remember where about a project to replace the TTL > can oscillator in a PC with a better quality one driven from a OCXO. That > is a lot of work for small gain. > > One thing about that study. I notice the author had t remove the PPS > reference clock. It looks like he was unabe to get the graph to move at > all with PPS attached. I'd like to see the same study done with a good > PPS reference clock let connected. Likely the results would be > uninteresting, just a flat graph. > > > On Wed, May 15, 2013 at 12:51 AM, Hal Murray <[email protected] > >wrote: > > > > > [email protected] said: > > > Maybe not you, but I think some people think "Oh my, NTP is not > checking > > the > > > time very often. It must not be accurate." That is thinking > backwards, > > > you need the long poll interval to see small errors in rate. But this > > > assumes a stable local clock. NTP balances this. > > > > That "balance" is assuming a classic ADEV type V curve. That assumption > > works better in old non-green systems that burned lots of power in an > idle > > loop when they didn't have any work to do. With modern systems, it's > easy > > to > > change the temperature significantly by starting/finishing a big chunk of > > work. > > > > External temperature changes can also be important. Every now and then, > I > > like to repost this link. This seems like a good opportunity. > > NTP temperature compensation > > http://www.ijs.si/time/temp-compensation/ > > > > > > > > -- > > These are my opinions. I hate spam. > > > > > > > > _______________________________________________ > > 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. > > > > > > -- > > Chris Albertson > Redondo Beach, California > _______________________________________________ > 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. > _______________________________________________ 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.
