On 2017-01-31 22:55, sean wrote: > On 2017-01-30, David Taylor <[email protected]> wrote: >> On 30/01/2017 04:13, sean wrote: >>> I'm real interested in NTP and accurate time, hence why I'm on this >>> newsgroup. I would like to look into getting a time sensor and I hear >>> the Garmin GPS 18X is what some folks run unless they need much more >>> precision. Is this still a pretty well regarding GPS unit for pretty >>> accurate (I know that's highly subjective) time keeping? This would be >>> a hobbyist thing and I'm not running an important business, if you were >>> going to ask. >>> Next question...Do most folks here use the NTPD client, or it is a >>> mixture of Chrony and openNTPD? Maybe some folks just go with what ships >>> with their OS? >>> The comparison chart is pretty nice and lays each option out nicely: >>> https://chrony.tuxfamily.org/comparison.html >>> I think that's all for now. Feel free to provide any URLs to any >>> resources I should check out about time sycing, NTP, etc. >> I have been running NTP on multiple systems since 2002, including Linux >> and Windows (2000 and later), both with hardware sync (GPS18, GPS18x and >> multiple GPS devices for the Raspberry Pi), and with LAN and Wi-Fi >> network sources. I find NTP easy to manage and monitor over multiple >> systems, and the fact that it runs on Windows, and can accept GPS >> devices on Windows very valuable. You can easily get within 10 >> microseconds in Linux (but be careful of the temperature and GPS antenna >> location), and within 200 microseconds on Windows when using an attached >> GPS/PPS device. > Thank you for the reply. I found your website about 3 weeks ago and got > the urge to checkout GPS devices, like the GPS18, Raspberry pi options, > etc. Thank you for it and all of the graphs. You certainly have many Pis > keep track of the time! I don't recall, are you apart of the NTP Pool? > I found your website to have a wealth of great information that's quite > well compiled and thoughout. I hope your health is much better this > year and that you're on the road to recovery. > Primarily I run FreeBSD and was surprised to learn that it can have > better precision than Linux, although the articles I read were FreeBSD > 8.0 era. Do you find FreeBSD generic kernel comparable with Linux? From > what it sounds like, a Raspberry Pi with the device below will give me > "pretty accurate" (my words) time, which I can use to sync my devices in > my home. >> http://www.satsignal.eu/mrtg/performance_ntp.php >> For the Raspberry Pi: >> https://store.uputronics.com/index.php?route=product/product&product_id=81 > That's pretty well priced, cheaper than the Garmin
For that and the below you also need power supply, antenna, and interface. http://www.ebay.com/itm/Trimble-Resolution-T-Timing-GPS-module-12ns-1pps/252474351979 http://www.ebay.com/itm/UBLOX-LEA-5T-high-precision-timing-GPS-module-dev-board-1PPS-USB-RS232-ntp-ser/251785217093 For easy as Pi there's the GPS HAT: https://www.adafruit.com/product/2324 which works fine on the Pi3 if you disable BT or switch BT to the mini-uart with a DT overlay despite AdaFruit statement (do web search for Adafruit Ultimate GPS HAT Pi3 NTP). Cheapest Garmin 18x LVC I have found anywhere is US$60 (shipping extra) from my local dealer who also ships world wide from LV, NV: http://www.gpscity.com/garmin-gps-18x-high-sensitivity-lvc.html http://www.gpscity.ca/garmin-gps-18x-high-sensitivity-lvc.html I run both of the above and average offset is low us with offset spiking up to about +/-50us, probably temperature swings. -- Take care. Thanks, Brian Inglis, Calgary, Alberta, Canada _______________________________________________ questions mailing list [email protected] http://lists.ntp.org/listinfo/questions
