NTPsec

NTP0: x86 SBC, NTPSec, NTP-disciplined (stratum 2)
Two Day - July 30, 2026 23:00 UTC

Report generated: Thu Jul 30 23:04:03 2026 UTC
Start Time: Tue Jul 28 23:04:02 2026 UTC
End Time: Thu Jul 30 23:04:02 2026 UTC
Report Period: 2.0 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 -91.240 -55.627 -39.817 1.216 43.857 66.840 153.278 83.674 122.467 24.917 1.336 µs 0.2623 3.895
Local Clock Frequency Offset -5.718 -3.305 -2.569 -1.293 -0.404 0.117 4.703 2.165 3.422 0.681 -1.373 ppm -0.4234 4.991

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 12.134 17.199 20.796 32.467 48.623 58.527 86.334 27.827 41.328 8.682 33.325 µs 0.7335 4.211

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 0.129 0.275 0.341 0.546 0.856 1.038 1.739 0.515 0.764 0.162 0.567 ppm 0.8302 4.45

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 -91.240 -55.627 -39.817 1.216 43.857 66.840 153.278 83.674 122.467 24.917 1.336 µs 0.2623 3.895

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 -5.718 -3.305 -2.569 -1.293 -0.404 0.117 4.703 2.165 3.422 0.681 -1.373 ppm -0.4234 4.991
Temp ZONE0 48.000 49.000 53.000 57.000 58.000 58.000 58.000 5.000 9.000 1.970 56.717 °C
Temp ZONE1 48.000 49.000 54.000 58.000 59.000 59.000 60.000 5.000 10.000 1.971 57.349 °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 -91.241 -55.628 -39.818 1.217 43.858 66.841 153.279 83.676 122.469 24.918 1.336 µs 0.2622 3.895

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 -59.312 -21.270 49.789 89.725 112.561 197.494 110.995 171.873 40.187 44.803 µs -3.554 27.13

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 -101.164 -65.485 5.422 42.688 64.905 136.467 108.173 166.069 39.626 -0.281 µs -3.793 29.27

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 -75.925 -36.643 33.258 70.208 92.840 178.808 106.851 168.765 39.242 27.575 µs -3.702 28.59

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 -98.912 -61.169 10.831 47.980 69.687 145.658 109.149 168.599 40.681 4.558 µs -3.851 28.89

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 -50.667 -10.078 62.776 101.738 125.683 215.111 111.816 176.350 40.359 56.690 µs -3.44 26.38

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 1.304 6.718 12.509 38.050 69.891 94.350 690.757 57.382 87.632 24.206 39.716 µs 7.851 140.7

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 10.0.50.100

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 0.001 0.004 0.007 0.019 0.041 0.057 8.357 0.034 0.053 0.104 0.022 ms 78.81 6329

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 5.481 8.186 18.492 44.899 62.417 724.804 36.713 56.936 16.160 21.588 µs 16.91 605.7

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 10.0.50.30

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 1.455 6.879 10.035 21.734 43.997 59.587 732.448 33.962 52.708 13.607 23.687 µs 14.87 600

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 1.759 6.217 8.868 19.907 44.141 62.153 491.454 35.273 55.936 14.551 22.496 µs 11.62 322.3

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 5.446 9.873 13.318 26.347 50.439 66.647 685.197 37.121 56.774 14.483 28.559 µs 12.9 494

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 -5.718 -3.305 -2.569 -1.293 -0.404 0.117 4.703 2.165 3.422 0.681 -1.373 ppm -0.4234 4.991
Local Clock Time Offset -91.240 -55.627 -39.817 1.216 43.857 66.840 153.278 83.674 122.467 24.917 1.336 µs 0.2623 3.895
Local RMS Frequency Jitter 0.129 0.275 0.341 0.546 0.856 1.038 1.739 0.515 0.764 0.162 0.567 ppm 0.8302 4.45
Local RMS Time Jitter 12.134 17.199 20.796 32.467 48.623 58.527 86.334 27.827 41.328 8.682 33.325 µs 0.7335 4.211
Server Jitter 10.0.50.10 1.304 6.718 12.509 38.050 69.891 94.350 690.757 57.382 87.632 24.206 39.716 µs 7.851 140.7
Server Jitter 10.0.50.100 0.001 0.004 0.007 0.019 0.041 0.057 8.357 0.034 0.053 0.104 0.022 ms 78.81 6329
Server Jitter 10.0.50.20 2.218 5.481 8.186 18.492 44.899 62.417 724.804 36.713 56.936 16.160 21.588 µs 16.91 605.7
Server Jitter 10.0.50.30 1.455 6.879 10.035 21.734 43.997 59.587 732.448 33.962 52.708 13.607 23.687 µs 14.87 600
Server Jitter 10.0.50.40 1.759 6.217 8.868 19.907 44.141 62.153 491.454 35.273 55.936 14.551 22.496 µs 11.62 322.3
Server Jitter 10.0.50.50 5.446 9.873 13.318 26.347 50.439 66.647 685.197 37.121 56.774 14.483 28.559 µs 12.9 494
Server Offset 10.0.50.10 -91.241 -55.628 -39.818 1.217 43.858 66.841 153.279 83.676 122.469 24.918 1.336 µs 0.2622 3.895
Server Offset 10.0.50.100 -310.154 -59.312 -21.270 49.789 89.725 112.561 197.494 110.995 171.873 40.187 44.803 µs -3.554 27.13
Server Offset 10.0.50.20 -347.796 -101.164 -65.485 5.422 42.688 64.905 136.467 108.173 166.069 39.626 -0.281 µs -3.793 29.27
Server Offset 10.0.50.30 -318.225 -75.925 -36.643 33.258 70.208 92.840 178.808 106.851 168.765 39.242 27.575 µs -3.702 28.59
Server Offset 10.0.50.40 -340.530 -98.912 -61.169 10.831 47.980 69.687 145.658 109.149 168.599 40.681 4.558 µs -3.851 28.89
Server Offset 10.0.50.50 -306.122 -50.667 -10.078 62.776 101.738 125.683 215.111 111.816 176.350 40.359 56.690 µs -3.44 26.38
Temp ZONE0 48.000 49.000 53.000 57.000 58.000 58.000 58.000 5.000 9.000 1.970 56.717 °C
Temp ZONE1 48.000 49.000 54.000 58.000 59.000 59.000 60.000 5.000 10.000 1.971 57.349 °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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