Rpi NTP server and PPM test

• So pi has 1PPM error rate on it’s clock. it should dirft ~1second per day

systemctl status systemd-timesyncd

root@lp-arm-5:~# timedatectl timesync-status
       Server: 192.168.10.196 (192.168.10.196)
Poll interval: 34min 8s (min: 32s; max 34min 8s)
         Leap: normal
      Version: 4
      Stratum: 1
    Reference: GPS
    Precision: 1us (-20)
Root distance: 0 (max: 5s)
       Offset: -79.759ms
        Delay: 177.920ms
       Jitter: 392.723ms
 Packet count: 437

root@lp-arm-5:~# timedatectl show-timesync
SystemNTPServers=192.168.10.196
FallbackNTPServers=0.debian.pool.ntp.org 1.debian.pool.ntp.org
ServerName=192.168.10.196
ServerAddress=192.168.10.196
RootDistanceMaxUSec=5s
PollIntervalMinUSec=32s
PollIntervalMaxUSec=34min 8s
PollIntervalUSec=34min 8s
NTPMessage={ Leap=0, Version=4, Mode=4, Stratum=1, Precision=-20, RootDelay=0, RootDispersion=0, Reference=GPS, OriginateTimestamp=Sat 2026-08-22 13:55:50 IST, ReceiveTimestamp=Sat 2026-08-22 13:55:50 IST, TransmitTimestamp=Sat 2026-08-22 13:55:50 IST, DestinationTimestamp=Sat 2026-08-22 13:55:50 IST, Ignored=yes, PacketCount=437, Jitter=392.723ms }
Frequency=278345

root@lp-arm-5:~# cat  /etc/systemd/timesyncd.conf
[Time]
NTP=192.168.10.196
FallbackNTP=0.debian.pool.ntp.org 1.debian.pool.ntp.org
[Time]
#NTP=
#FallbackNTP=0.debian.pool.ntp.org 1.debian.pool.ntp.org 2.debian.pool.ntp.org 3.debian.pool.ntp.org
#RootDistanceMaxSec=5
#PollIntervalMinSec=32
#PollIntervalMaxSec=2048
#ConnectionRetrySec=30
#SaveIntervalSec=60

• stoped ntp service

root@lp-arm-5:~# timedatectl  && ntpdate -q 192.168.10.90
               Local time: Sat 2026-08-22 14:55:11 IST
           Universal time: Sat 2026-08-22 09:25:11 UTC
                 RTC time: Sat 2026-08-22 09:25:11
                Time zone: Asia/Kolkata (IST, +0530)
System clock synchronized: yes
              NTP service: inactive
          RTC in local TZ: no
2026-08-22 14:55:11.120999 (+0530) +0.017578 +/- 0.004635 192.168.10.90 s1 no-leap



root@lp-arm-5:~# while true; do     ntpdate -q 192.168.10.90;     sleep 1; done
2026-08-22 14:56:07.223000 (+0530) +0.014346 +/- 0.009613 192.168.10.90 s1 no-leap
2026-08-22 14:56:08.310000 (+0530) +0.016642 +/- 0.008483 192.168.10.90 s1 no-leap
2026-08-22 14:56:09.393000 (+0530) +0.019201 +/- 0.004101 192.168.10.90 s1 no-leap
2026-08-22 14:56:10.473000 (+0530) +0.016223 +/- 0.012315 192.168.10.90 s1 no-leap
2026-08-22 14:56:11.563000 (+0530) +0.022523 +/- 0.005409 192.168.10.90 s1 no-leap
2026-08-22 14:56:12.657000 (+0530) +0.020756 +/- 0.004506 192.168.10.90 s1 no-leap
2026-08-22 14:56:13.748000 (+0530) +0.027691 +/- 0.013002 192.168.10.90 s1 no-leap
2026-08-22 14:56:14.824999 (+0530) +0.020858 +/- 0.004934 192.168.10.90 s1 no-leap
2026-08-22 14:56:15.902000 (+0530) +0.020752 +/- 0.006207 192.168.10.90 s1 no-leap
2026-08-22 14:56:16.980000 (+0530) +0.022216 +/- 0.004206 192.168.10.90 s1 no-leap
2026-08-22 14:56:18.081999 (+0530) +0.021030 +/- 0.007626 192.168.10.90 s1 no-leap
2026-08-22 14:56:19.162000 (+0530) +0.022143 +/- 0.005573 192.168.10.90 s1 no-leap
2026-08-22 14:56:20.237000 (+0530) +0.020466 +/- 0.005176 192.168.10.90 s1 no-leap
2026-08-22 14:56:21.313000 (+0530) +0.018130 +/- 0.005373 192.168.10.90 s1 no-leap
2026-08-22 14:56:22.394000 (+0530) +0.019911 +/- 0.005312 192.168.10.90 s1 no-leap
2026-08-22 14:56:23.501999 (+0530) +0.022654 +/- 0.006490 192.168.10.90 s1 no-leap
2026-08-22 14:56:24.587999 (+0530) +0.023260 +/- 0.011551 192.168.10.90 s1 no-leap