NTPsec

NTP0: x86 SBC, NTPSec, NTP-disciplined (stratum 2)
One Day - July 31, 2026 04:00 UTC

Report generated: Fri Jul 31 04:02:52 2026 UTC
Start Time: Thu Jul 30 04:02:52 2026 UTC
End Time: Fri Jul 31 04:02:52 2026 UTC
Report Period: 1.0 days

Return to It's About Time

Section Time Frame NTP Server
Local Clock Time/Frequency Offsets One Hour NTP0: x86 SBC, NTPSec, NTP-disciplined (stratum 2)
Local RMS Time Jitter Three Hour NTP1: RPi4B, Uputronics M8, NTPSec
Local RMS Frequency Jitter Six Hour NTP2: CM4, Bollar ZED-F9T, NTPSec
Local Clock Time Offset Histogram Twelve Hour NTP3: CM5, TimeHat LEA-M8T, NTPSec
Local Temperatures One Day NTP4: SecureSync, Rubidium, NTP (Classic)
Local Frequency/Temp Two Day NTP5: RPi3B+, Uputronics MAX-M8Q, NTPSec
Local GPS Three Day NTP6: CM4, TimeBeat OTC Mini, PTP
Server Offsets Seven Day NTP7: LeoNTP, Standalone GNSS, Firmware
Server Jitters Fourteen Day (Updated Daily)
Summary One Month (Updated Daily)
NTPQ Stats
GNSS Performance

NTP0 runs on a low-power x86 single board computer with no GNSS or PPS hardware; it is disciplined over the network by NTP only (stratum 2, from the GNSS fleet). It processes and renders the NTPViz reports and lets us observe the effects of CPU load on NTP jitter.

If graphs don't match report time above, force refresh the browser. The images have been cached.


Local Clock Time/Frequency Offsets

local offset plot

Percentiles...... Ranges...... Skew- Kurt-
Name Min1%5%50%95% 99%Max   90%98%StdDev  MeanUnits nessosis
Local Clock Time Offset -87.565 -55.805 -40.350 1.462 44.571 68.930 123.176 84.921 124.735 25.202 1.306 µs 0.2262 3.695
Local Clock Frequency Offset -4.680 -3.308 -2.603 -1.317 -0.416 0.133 4.703 2.187 3.441 0.692 -1.391 ppm -0.2847 5.435

The time and frequency offsets between the ntpd calculated time and the local system clock. Showing frequency offset (red, in parts per million, scale on right) and the time offset (blue, in μs, scale on left). Quick changes in time offset will lead to larger frequency offsets.

These are fields 3 (time) and 4 (frequency) from the loopstats log file.



Local RMS Time Jitter

local jitter plot

Percentiles...... Ranges...... Skew- Kurt-
Name Min1%5%50%95% 99%Max   90%98%StdDev  MeanUnits nessosis
Local RMS Time Jitter 13.106 17.286 20.978 33.608 49.711 59.183 84.561 28.733 41.897 8.826 34.270 µs 0.6065 3.92

The RMS Jitter of the local clock offset. In other words, how fast the local clock offset is changing.

Lower is better. An ideal system would be a horizontal line at 0μs.

RMS jitter is field 5 in the loopstats log file.



Local RMS Frequency Jitter

local stability plot

Percentiles...... Ranges...... Skew- Kurt-
Name Min1%5%50%95% 99%Max   90%98%StdDev  MeanUnits nessosis
Local RMS Frequency Jitter 0.200 0.281 0.345 0.562 0.876 1.042 1.453 0.532 0.760 0.164 0.580 ppm 0.6967 3.806

The RMS Frequency Jitter (aka wander) of the local clock's frequency. In other words, how fast the local clock changes frequency.

Lower is better. An ideal clock would be a horizontal line at 0ppm.

RMS Frequency Jitter is field 6 in the loopstats log file.



Local Clock Time Offset Histogram

local offset histogram plot

Percentiles...... Ranges...... Skew- Kurt-
Name Min1%5%50%95% 99%Max   90%98%StdDev  MeanUnits nessosis
Local Clock Offset -87.565 -55.805 -40.350 1.462 44.571 68.930 123.176 84.921 124.735 25.202 1.306 µs 0.2262 3.695

The clock offsets of the local clock as a histogram.

The Local Clock Offset is field 3 from the loopstats log file.



Local Temperatures

local temps plot

Local temperatures. These will be site-specific depending upon what temperature sensors you collect data from. Temperature changes affect the local clock crystal frequency and stability. The math of how temperature changes frequency is complex, and also depends on crystal aging. So there is no easy way to correct for it in software. This is the single most important component of frequency drift.

The Local Temperatures are from field 3 from the tempstats log file.



Local Frequency/Temp

local freq temps plot

Percentiles...... Ranges...... Skew- Kurt-
Name Min1%5%50%95% 99%Max   90%98%StdDev  MeanUnits nessosis
Local Clock Frequency Offset -4.680 -3.308 -2.603 -1.317 -0.416 0.133 4.703 2.187 3.441 0.692 -1.391 ppm -0.2847 5.435
Temp ZONE0 48.000 48.000 50.000 58.000 58.000 58.000 58.000 8.000 10.000 2.425 56.707 °C
Temp ZONE1 48.000 49.000 50.000 58.000 59.000 59.000 60.000 9.000 10.000 2.505 57.237 °C

The frequency offsets and temperatures. Showing frequency offset (red, in parts per million, scale on right) and the temperatures.

These are field 4 (frequency) from the loopstats log file, and field 3 from the tempstats log file.



Server Offsets

peer offsets plot

The offset of all refclocks and servers. This can be useful to see if offset changes are happening in a single clock or all clocks together.

Clock Offset is field 5 in the peerstats log file.



Server Offset 10.0.50.10

peer offset 10.0.50.10 plot

Percentiles...... Ranges...... Skew- Kurt-
Name Min1%5%50%95% 99%Max   90%98%StdDev  MeanUnits nessosis
Server Offset 10.0.50.10 -87.566 -55.806 -40.351 1.463 44.572 68.931 123.177 84.923 124.737 25.202 1.306 µs 0.2262 3.695

The offset of a server in seconds. This is useful to see how the measured offset is behaving.

The chart also plots offset±rtt, where rtt is the round trip time to the server. NTP can not really know the offset of a remote chimer, NTP computes it by subtracting rtt/2 from the offset. Plotting the offset±rtt reverses this calculation to more easily see the effects of rtt changes.

Closer to 0s is better. An ideal system would be a horizontal line at 0s. Typical 90% ranges may be: local LAN server 80µs; 90% ranges for WAN server may be 4ms and much larger.

Clock Offset is field 5 in the peerstats log file. The Round Trip Time (rtt) is field 6 in the peerstats log file.



Server Offset 10.0.50.100

peer offset 10.0.50.100 plot

Percentiles...... Ranges...... Skew- Kurt-
Name Min1%5%50%95% 99%Max   90%98%StdDev  MeanUnits nessosis
Server Offset 10.0.50.100 -310.154 -254.717 -81.787 39.568 189.999 235.960 317.954 271.786 490.677 78.814 33.744 µs -0.5284 6.528

The offset of a server in seconds. This is useful to see how the measured offset is behaving.

The chart also plots offset±rtt, where rtt is the round trip time to the server. NTP can not really know the offset of a remote chimer, NTP computes it by subtracting rtt/2 from the offset. Plotting the offset±rtt reverses this calculation to more easily see the effects of rtt changes.

Closer to 0s is better. An ideal system would be a horizontal line at 0s. Typical 90% ranges may be: local LAN server 80µs; 90% ranges for WAN server may be 4ms and much larger.

Clock Offset is field 5 in the peerstats log file. The Round Trip Time (rtt) is field 6 in the peerstats log file.



Server Offset 10.0.50.20

peer offset 10.0.50.20 plot

Percentiles...... Ranges...... Skew- Kurt-
Name Min1%5%50%95% 99%Max   90%98%StdDev  MeanUnits nessosis
Server Offset 10.0.50.20 -347.796 -306.332 -128.952 -4.922 142.974 186.947 262.748 271.926 493.279 77.968 -11.944 µs -0.5719 6.727

The offset of a server in seconds. This is useful to see how the measured offset is behaving.

The chart also plots offset±rtt, where rtt is the round trip time to the server. NTP can not really know the offset of a remote chimer, NTP computes it by subtracting rtt/2 from the offset. Plotting the offset±rtt reverses this calculation to more easily see the effects of rtt changes.

Closer to 0s is better. An ideal system would be a horizontal line at 0s. Typical 90% ranges may be: local LAN server 80µs; 90% ranges for WAN server may be 4ms and much larger.

Clock Offset is field 5 in the peerstats log file. The Round Trip Time (rtt) is field 6 in the peerstats log file.



Server Offset 10.0.50.30

peer offset 10.0.50.30 plot

Percentiles...... Ranges...... Skew- Kurt-
Name Min1%5%50%95% 99%Max   90%98%StdDev  MeanUnits nessosis
Server Offset 10.0.50.30 -318.225 -275.814 -93.805 22.576 169.350 216.083 278.848 263.155 491.897 77.146 16.127 µs -0.5533 6.759

The offset of a server in seconds. This is useful to see how the measured offset is behaving.

The chart also plots offset±rtt, where rtt is the round trip time to the server. NTP can not really know the offset of a remote chimer, NTP computes it by subtracting rtt/2 from the offset. Plotting the offset±rtt reverses this calculation to more easily see the effects of rtt changes.

Closer to 0s is better. An ideal system would be a horizontal line at 0s. Typical 90% ranges may be: local LAN server 80µs; 90% ranges for WAN server may be 4ms and much larger.

Clock Offset is field 5 in the peerstats log file. The Round Trip Time (rtt) is field 6 in the peerstats log file.



Server Offset 10.0.50.40

peer offset 10.0.50.40 plot

Percentiles...... Ranges...... Skew- Kurt-
Name Min1%5%50%95% 99%Max   90%98%StdDev  MeanUnits nessosis
Server Offset 10.0.50.40 -340.530 -303.231 -120.921 0.139 148.339 192.976 272.179 269.260 496.207 78.645 -6.917 µs -0.598 6.762

The offset of a server in seconds. This is useful to see how the measured offset is behaving.

The chart also plots offset±rtt, where rtt is the round trip time to the server. NTP can not really know the offset of a remote chimer, NTP computes it by subtracting rtt/2 from the offset. Plotting the offset±rtt reverses this calculation to more easily see the effects of rtt changes.

Closer to 0s is better. An ideal system would be a horizontal line at 0s. Typical 90% ranges may be: local LAN server 80µs; 90% ranges for WAN server may be 4ms and much larger.

Clock Offset is field 5 in the peerstats log file. The Round Trip Time (rtt) is field 6 in the peerstats log file.



Server Offset 10.0.50.50

peer offset 10.0.50.50 plot

Percentiles...... Ranges...... Skew- Kurt-
Name Min1%5%50%95% 99%Max   90%98%StdDev  MeanUnits nessosis
Server Offset 10.0.50.50 -306.122 -244.563 -70.815 51.005 198.538 244.876 328.369 269.353 489.439 78.262 45.689 µs -0.607 6.671

The offset of a server in seconds. This is useful to see how the measured offset is behaving.

The chart also plots offset±rtt, where rtt is the round trip time to the server. NTP can not really know the offset of a remote chimer, NTP computes it by subtracting rtt/2 from the offset. Plotting the offset±rtt reverses this calculation to more easily see the effects of rtt changes.

Closer to 0s is better. An ideal system would be a horizontal line at 0s. Typical 90% ranges may be: local LAN server 80µs; 90% ranges for WAN server may be 4ms and much larger.

Clock Offset is field 5 in the peerstats log file. The Round Trip Time (rtt) is field 6 in the peerstats log file.



Server Jitters

peer jitters plot

The RMS Jitter of all refclocks and servers. Jitter is the current estimated dispersion, in other words the variation in offset between samples.

Closer to 0s is better. An ideal system would be a horizontal line at 0s.

RMS Jitter is field 8 in the peerstats log file.



Server Jitter 10.0.50.10

peer jitter 10.0.50.10 plot

Percentiles...... Ranges...... Skew- Kurt-
Name Min1%5%50%95% 99%Max   90%98%StdDev  MeanUnits nessosis
Server Jitter 10.0.50.10 1.706 6.412 12.203 38.236 70.900 94.235 663.740 58.697 87.823 22.760 39.714 µs 6.415 112.4

The RMS Jitter of a server. Jitter is the current estimated dispersion, in other words the variation in offset between samples.

Closer to 0s is better. An ideal system would be a horizontal line at 0s.

RMS Jitter is field 8 in the peerstats log file.



Server Jitter 10.0.50.100

peer jitter 10.0.50.100 plot

Percentiles...... Ranges...... Skew- Kurt-
Name Min1%5%50%95% 99%Max   90%98%StdDev  MeanUnits nessosis
Server Jitter 10.0.50.100 1.297 3.864 6.950 18.740 40.496 56.285 442.400 33.546 52.421 12.911 20.904 µs 10.75 322.6

The RMS Jitter of a server. Jitter is the current estimated dispersion, in other words the variation in offset between samples.

Closer to 0s is better. An ideal system would be a horizontal line at 0s.

RMS Jitter is field 8 in the peerstats log file.



Server Jitter 10.0.50.20

peer jitter 10.0.50.20 plot

Percentiles...... Ranges...... Skew- Kurt-
Name Min1%5%50%95% 99%Max   90%98%StdDev  MeanUnits nessosis
Server Jitter 10.0.50.20 2.218 5.354 8.049 18.436 44.899 61.807 403.021 36.850 56.453 13.898 21.517 µs 8.716 209.2

The RMS Jitter of a server. Jitter is the current estimated dispersion, in other words the variation in offset between samples.

Closer to 0s is better. An ideal system would be a horizontal line at 0s.

RMS Jitter is field 8 in the peerstats log file.



Server Jitter 10.0.50.30

peer jitter 10.0.50.30 plot

Percentiles...... Ranges...... Skew- Kurt-
Name Min1%5%50%95% 99%Max   90%98%StdDev  MeanUnits nessosis
Server Jitter 10.0.50.30 3.057 6.860 9.969 21.455 43.530 57.930 395.015 33.561 51.070 11.305 23.327 µs 4.763 124.7

The RMS Jitter of a server. Jitter is the current estimated dispersion, in other words the variation in offset between samples.

Closer to 0s is better. An ideal system would be a horizontal line at 0s.

RMS Jitter is field 8 in the peerstats log file.



Server Jitter 10.0.50.40

peer jitter 10.0.50.40 plot

Percentiles...... Ranges...... Skew- Kurt-
Name Min1%5%50%95% 99%Max   90%98%StdDev  MeanUnits nessosis
Server Jitter 10.0.50.40 2.683 6.185 8.814 20.014 44.220 61.119 408.464 35.406 54.934 13.057 22.486 µs 7.496 190.5

The RMS Jitter of a server. Jitter is the current estimated dispersion, in other words the variation in offset between samples.

Closer to 0s is better. An ideal system would be a horizontal line at 0s.

RMS Jitter is field 8 in the peerstats log file.



Server Jitter 10.0.50.50

peer jitter 10.0.50.50 plot

Percentiles...... Ranges...... Skew- Kurt-
Name Min1%5%50%95% 99%Max   90%98%StdDev  MeanUnits nessosis
Server Jitter 10.0.50.50 4.685 10.000 13.428 25.976 51.177 67.619 361.094 37.749 57.619 13.451 28.501 µs 5.609 114.8

The RMS Jitter of a server. Jitter is the current estimated dispersion, in other words the variation in offset between samples.

Closer to 0s is better. An ideal system would be a horizontal line at 0s.

RMS Jitter is field 8 in the peerstats log file.



Summary


Percentiles...... Ranges...... Skew- Kurt-
Name Min1%5%50%95% 99%Max   90%98%StdDev  MeanUnits nessosis
Local Clock Frequency Offset -4.680 -3.308 -2.603 -1.317 -0.416 0.133 4.703 2.187 3.441 0.692 -1.391 ppm -0.2847 5.435
Local Clock Time Offset -87.565 -55.805 -40.350 1.462 44.571 68.930 123.176 84.921 124.735 25.202 1.306 µs 0.2262 3.695
Local RMS Frequency Jitter 0.200 0.281 0.345 0.562 0.876 1.042 1.453 0.532 0.760 0.164 0.580 ppm 0.6967 3.806
Local RMS Time Jitter 13.106 17.286 20.978 33.608 49.711 59.183 84.561 28.733 41.897 8.826 34.270 µs 0.6065 3.92
Server Jitter 10.0.50.10 1.706 6.412 12.203 38.236 70.900 94.235 663.740 58.697 87.823 22.760 39.714 µs 6.415 112.4
Server Jitter 10.0.50.100 1.297 3.864 6.950 18.740 40.496 56.285 442.400 33.546 52.421 12.911 20.904 µs 10.75 322.6
Server Jitter 10.0.50.20 2.218 5.354 8.049 18.436 44.899 61.807 403.021 36.850 56.453 13.898 21.517 µs 8.716 209.2
Server Jitter 10.0.50.30 3.057 6.860 9.969 21.455 43.530 57.930 395.015 33.561 51.070 11.305 23.327 µs 4.763 124.7
Server Jitter 10.0.50.40 2.683 6.185 8.814 20.014 44.220 61.119 408.464 35.406 54.934 13.057 22.486 µs 7.496 190.5
Server Jitter 10.0.50.50 4.685 10.000 13.428 25.976 51.177 67.619 361.094 37.749 57.619 13.451 28.501 µs 5.609 114.8
Server Offset 10.0.50.10 -87.566 -55.806 -40.351 1.463 44.572 68.931 123.177 84.923 124.737 25.202 1.306 µs 0.2262 3.695
Server Offset 10.0.50.100 -310.154 -254.717 -81.787 39.568 189.999 235.960 317.954 271.786 490.677 78.814 33.744 µs -0.5284 6.528
Server Offset 10.0.50.20 -347.796 -306.332 -128.952 -4.922 142.974 186.947 262.748 271.926 493.279 77.968 -11.944 µs -0.5719 6.727
Server Offset 10.0.50.30 -318.225 -275.814 -93.805 22.576 169.350 216.083 278.848 263.155 491.897 77.146 16.127 µs -0.5533 6.759
Server Offset 10.0.50.40 -340.530 -303.231 -120.921 0.139 148.339 192.976 272.179 269.260 496.207 78.645 -6.917 µs -0.598 6.762
Server Offset 10.0.50.50 -306.122 -244.563 -70.815 51.005 198.538 244.876 328.369 269.353 489.439 78.262 45.689 µs -0.607 6.671
Temp ZONE0 48.000 48.000 50.000 58.000 58.000 58.000 58.000 8.000 10.000 2.425 56.707 °C
Temp ZONE1 48.000 49.000 50.000 58.000 59.000 59.000 60.000 9.000 10.000 2.505 57.237 °C
Summary as CSV file

Our production NTP servers share the same mast-mounted Tallysman Accutenna® TW3972 Triple Band GNSS Antenna + L-band Correction Services antenna using a Tallysman TW164 1-to-4 Port Smart Power GNSS Signal Splitter. No external NTP servers are contacted and all servers, with the exception of NTP6, the LeoNTP 1200, poll each other. Internal NTP clients poll NTP4 or NTP6.

The LeoNTP 1200 is a black-box appliance that doesn't support timing reporting. Its status can be checked by viwing the Server Jitter & Offset from any of the other servers. It can be found at NTP7 or leontp.bollar.com (10.0.50.100). The LeoNTP link above will take you to the Server Jitter between the LeoNTP and the currently selected server.

NTPQ Stats

NTPQ Statistics are not not available for this NTP server.'

GNSS Performance

GNSS Performance is not available for this NTP server.'

Glossary:

frequency offset:
The difference between the ntpd calculated frequency and the local system clock frequency (usually in parts per million, ppm)
jitter, dispersion:
The short term change in a value. NTP measures Local Time Jitter, Refclock Jitter, and Server Jitter in seconds. Local Frequency Jitter is in ppm or ppb.
ms, millisecond:
One thousandth of a second = 0.001 seconds, 1e-3 seconds
mu, mean:
The arithmetic mean: the sum of all the values divided by the number of values. The formula for mu is: "mu = (∑xi) / N". Where xi denotes the data points and N is the number of data points.
ns, nanosecond:
One billionth of a second, also one thousandth of a microsecond, 0.000000001 seconds and 1e-9 seconds.
percentile:
The value below which a given percentage of values fall.
ppb, parts per billion:
Ratio between two values. These following are all the same: 1 ppb, one in one billion, 1/1,000,000,000, 0.000,000,001, 1e-9 and 0.000,000,1%
ppm, parts per million:
Ratio between two values. These following are all the same: 1 ppm, one in one million, 1/1,000,000, 0.000,001, and 0.000,1%
‰, parts per thousand:
Ratio between two values. These following are all the same: 1 ‰. one in one thousand, 1/1,000, 0.001, and 0.1%
refclock:
Reference clock, a local GPS module or other local source of time.
remote clock:
Any clock reached over the network, LAN or WAN. Also called a peer or server.
time offset:
The difference between the ntpd calculated time and the local system clock's time. Also called phase offset.
σ, sigma:
Sigma denotes the standard deviation (SD) and is centered on the arithmetic mean of the data set. The SD is simply the square root of the variance of the data set. Two sigma is simply twice the standard deviation. Three sigma is three times sigma. Smaller is better.
The formula for sigma is: "σ = √[ ∑(xi-mu)^2 / N ]". Where xi denotes the data points and N is the number of data points.
Skewness, Skew:
The skewness of a random variable X is the third standardized moment and is a dimension-less ratio. ntpviz uses the FIsher-Pearson moment of skewness. There are other different ways to calculate Skewness Wikipedia describes Skewness best: "The qualitative interpretation of the skew is complicated and unintuitive."
A normal distribution has a skewness of zero.
Kurtosis, Kurt:
The kurtosis of a random variable X is the fourth standardized moment and is a dimension-less ratio. ntpviz uses standard Kurtosis. There are other different ways to calculate Kurtosis.
A normal distribution has a Kurtosis of three. NIST describes a kurtosis over three as "heavy tailed" and one under three as "light tailed".
upstream clock:
Any server or reference clock used as a source of time.
µs, us, microsecond:
One millionth of a second, also one thousandth of a millisecond, 0.000,001 seconds, and 1e-6 seconds.



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