On 16/12/2021 23:37, [email protected] wrote:
Hi,
just wondering if a PI4 could be a suitable NTP server for a small lab (and
maybe with some other NTP servers for my company, about 2000 clients).
Main use is for correct timestamp on logs/computer time sync.
I setup the NTP using Adafruit Ultimate GPS shield(with battery), and the
GPS/GLONASS Antenna(cheap one, not a timing antenna). Antenna is on a roof
window with a small metal base, outside.
What is the accuracy I could expect from it?
You can see the offsets reported by a number of Raspberry Pi NTP servers here:
https://www.satsignal.eu/mrtg/performance_ntp.php
As a very rough guide I would expect a PPS-based RPi to be within 100 us
easily, and perhaps considerably better (~10 us) in a constant temperature
environment, and with no other load. I don't know about load capacity as I've
not tested that, but here it's serving perhaps 50 devices. With classic NTP
which is what I use there will be a period before the offset becomes near-zero
so 24 x 7 is the way to operate.
Although there are some devices on that page with LAN, 2.4 GHz or 5 GHz
connections, for beat accuracy you must use the PPS signal from the GPS as you
know. The "o" tally code suggests that's OK.
I suggest using the "pool" directive rather than multiple pool servers:
https://www.satsignal.eu/ntp/setup.html#pool
Cheers,
David
--
SatSignal Software - Quality software for you
Web: https://www.satsignal.eu
Email: [email protected]
Twitter: @gm8arv
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