On Wed, Feb 24, 2016 at 3:22 PM, Neil Green <[email protected]> wrote: > I currently operate a stratum 1 NTP server in the NTP pool using a U-Blox > Max-7Q GPS module with PPS attached to, variously, a Raspberry Pi via GPIO or > a Celeron mini PC via serial DB-9. The machine does nothing but serve time to > the pool. Operating systems of choice are Debian or FreeBSD. > > > What would be my next step up be, hardware-wise, in terms of improving > precision, stability, etc? A GPSDO? Budget is limited as far as these things > go - about £150 UK/$210 US.
For what purpose? In my experience, NTP is able to sync other systems to within 10-100 microseconds of an NTP server on a LAN. The vagaries of the internet mean that it's unlikely for NTP clients to sync any closer than a few tens of milliseconds. The Pi is a decent system, but its ethernet port is connected via USB, so accuracy isn't as good as it would be on a different, non-USB system. It's quite satisfactory for serving time to the internet using NTP. A GPSDO is handy if you need better precision (but the Pi and the internet can't deliver that better precision, so this is not a major advantage for NTP) or holdover in case of issues with GPS. Many also emit a stable reference frequency: this is useful for providing a common reference for test equipment like frequency counters, or for radio/microwave systems that need very high stability. If you don't have such needs, a GPSDO will be of limited use. > I appreciate this is basic stuff compared to the usual discussions but this > doesn't seem the right question to ask on the NTP lists. Any help > appreciated. Thanks. Welcome, and thanks for providing a server in the NTP pool. Cheers! -Pete -- Pete Stephenson _______________________________________________ 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.
