NTPsec

NTP0: x86 SBC, NTPSec, NTP-disciplined (stratum 2)
Three Hour - September 14, 2026 05:00 UTC

Report generated: Mon Sep 14 05:00:50 2026 UTC
Start Time: Mon Sep 14 02:00:50 2026 UTC
End Time: Mon Sep 14 05:00:50 2026 UTC
Report Period: 0.1 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 -69.114 -48.633 -35.452 0.126 41.713 61.083 125.414 77.165 109.716 23.462 1.458 µs 0.3784 3.73
Local Clock Frequency Offset -4.255 -3.016 -2.439 -1.324 -0.385 0.042 0.303 2.054 3.058 0.646 -1.357 ppm -0.4152 3.6

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 13.243 16.124 20.963 30.772 44.684 55.238 71.789 23.721 39.114 7.523 31.722 µs 0.8336 4.899

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 194.320 260.343 360.811 534.453 811.822 985.603 1,337.010 451.011 725.260 142.678 556.028 ppb 0.9291 5.105

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 -69.114 -48.633 -35.452 0.126 41.713 61.083 125.414 77.165 109.716 23.462 1.458 µs 0.3784 3.73

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 -4.255 -3.016 -2.439 -1.324 -0.385 0.042 0.303 2.054 3.058 0.646 -1.357 ppm -0.4152 3.6
Temp ZONE0 55.000 55.000 56.000 59.000 62.000 62.000 62.000 6.000 7.000 2.088 59.028 °C
Temp ZONE1 56.000 56.000 56.000 61.000 64.000 64.000 64.000 8.000 8.000 2.178 60.250 °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 -69.115 -48.634 -35.453 0.127 41.714 61.084 125.415 77.167 109.718 23.462 1.458 µs 0.3783 3.729

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 7.166 17.316 25.906 47.766 85.618 105.812 143.185 59.712 88.496 18.903 50.430 µs 0.8616 3.978

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 -29.827 -16.598 -9.995 12.145 48.217 69.579 129.541 58.212 86.177 19.130 15.063 µs 0.9729 4.905

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 -10.898 3.184 12.674 40.880 79.673 96.019 159.369 66.999 92.835 20.611 43.163 µs 0.6046 4.091

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 -25.094 -12.995 -3.483 17.423 57.296 78.633 130.227 60.779 91.628 19.592 21.271 µs 1.103 5.356

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 2.073 23.578 37.270 66.538 104.318 120.825 171.494 67.048 97.247 20.624 68.095 µs 0.4167 3.586

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 2.056 3.663 8.185 30.890 59.317 76.832 95.591 51.132 73.169 15.770 31.671 µs 0.5826 3.415

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 1.016 1.754 2.307 10.386 32.479 44.699 80.781 30.172 42.945 9.727 12.696 µs 1.599 6.767

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 3.395 5.986 8.926 19.738 40.761 52.504 82.693 31.835 46.518 10.034 21.574 µs 1.358 6.402

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 2.230 3.526 5.602 19.336 44.301 60.796 85.560 38.699 57.270 12.206 21.342 µs 1.235 5.617

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 3.486 4.697 6.748 16.704 39.231 57.226 110.088 32.483 52.529 11.205 19.262 µs 2.122 11.81

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 0.005 0.010 0.014 0.026 0.048 0.063 10.265 0.034 0.053 0.470 0.049 ms 21.69 471.5

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.



Summary


Percentiles...... Ranges...... Skew- Kurt-
Name Min1%5%50%95% 99%Max   90%98%StdDev  MeanUnits nessosis
Local Clock Frequency Offset -4.255 -3.016 -2.439 -1.324 -0.385 0.042 0.303 2.054 3.058 0.646 -1.357 ppm -0.4152 3.6
Local Clock Time Offset -69.114 -48.633 -35.452 0.126 41.713 61.083 125.414 77.165 109.716 23.462 1.458 µs 0.3784 3.73
Local RMS Frequency Jitter 194.320 260.343 360.811 534.453 811.822 985.603 1,337.010 451.011 725.260 142.678 556.028 ppb 0.9291 5.105
Local RMS Time Jitter 13.243 16.124 20.963 30.772 44.684 55.238 71.789 23.721 39.114 7.523 31.722 µs 0.8336 4.899
Server Jitter 10.0.50.10 2.056 3.663 8.185 30.890 59.317 76.832 95.591 51.132 73.169 15.770 31.671 µs 0.5826 3.415
Server Jitter 10.0.50.100 1.016 1.754 2.307 10.386 32.479 44.699 80.781 30.172 42.945 9.727 12.696 µs 1.599 6.767
Server Jitter 10.0.50.20 3.395 5.986 8.926 19.738 40.761 52.504 82.693 31.835 46.518 10.034 21.574 µs 1.358 6.402
Server Jitter 10.0.50.30 2.230 3.526 5.602 19.336 44.301 60.796 85.560 38.699 57.270 12.206 21.342 µs 1.235 5.617
Server Jitter 10.0.50.40 3.486 4.697 6.748 16.704 39.231 57.226 110.088 32.483 52.529 11.205 19.262 µs 2.122 11.81
Server Jitter 10.0.50.50 0.005 0.010 0.014 0.026 0.048 0.063 10.265 0.034 0.053 0.470 0.049 ms 21.69 471.5
Server Offset 10.0.50.10 -69.115 -48.634 -35.453 0.127 41.714 61.084 125.415 77.167 109.718 23.462 1.458 µs 0.3783 3.729
Server Offset 10.0.50.100 7.166 17.316 25.906 47.766 85.618 105.812 143.185 59.712 88.496 18.903 50.430 µs 0.8616 3.978
Server Offset 10.0.50.20 -29.827 -16.598 -9.995 12.145 48.217 69.579 129.541 58.212 86.177 19.130 15.063 µs 0.9729 4.905
Server Offset 10.0.50.30 -10.898 3.184 12.674 40.880 79.673 96.019 159.369 66.999 92.835 20.611 43.163 µs 0.6046 4.091
Server Offset 10.0.50.40 -25.094 -12.995 -3.483 17.423 57.296 78.633 130.227 60.779 91.628 19.592 21.271 µs 1.103 5.356
Server Offset 10.0.50.50 2.073 23.578 37.270 66.538 104.318 120.825 171.494 67.048 97.247 20.624 68.095 µs 0.4167 3.586
Temp ZONE0 55.000 55.000 56.000 59.000 62.000 62.000 62.000 6.000 7.000 2.088 59.028 °C
Temp ZONE1 56.000 56.000 56.000 61.000 64.000 64.000 64.000 8.000 8.000 2.178 60.250 °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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