NTPsec

NTP0: x86 SBC, NTPSec, NTP-disciplined (stratum 2)
Seven Day - September 15, 2026 09:00 UTC

Report generated: Tue Sep 15 09:08:14 2026 UTC
Start Time: Tue Sep 8 09:08:12 2026 UTC
End Time: Tue Sep 15 09:08:12 2026 UTC
Report Period: 7.0 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 -97.493 -55.069 -42.440 1.372 46.313 66.236 163.209 88.753 121.305 26.597 1.385 µs 0.1861 3.151
Local Clock Frequency Offset -5.144 -3.390 -2.726 -1.471 -0.390 0.080 1.390 2.336 3.470 0.723 -1.512 ppm -0.2762 3.408

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 4.984 12.989 19.866 34.661 50.235 58.539 86.796 30.369 45.550 9.171 34.858 µs 0.1594 3.565

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 0.099 0.213 0.337 0.609 0.909 1.059 1.717 0.572 0.846 0.173 0.615 ppm 0.2399 3.533

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 -97.493 -55.069 -42.440 1.372 46.313 66.236 163.209 88.753 121.305 26.597 1.385 µs 0.1861 3.151

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 -5.144 -3.390 -2.726 -1.471 -0.390 0.080 1.390 2.336 3.470 0.723 -1.512 ppm -0.2762 3.408
Temp ZONE0 53.000 54.000 55.000 62.000 63.000 63.000 64.000 8.000 9.000 2.105 61.894 °C
Temp ZONE1 54.000 55.000 56.000 64.000 65.000 65.000 66.000 9.000 10.000 2.136 63.247 °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 -97.494 -55.070 -42.441 1.373 46.314 66.237 163.210 88.755 121.307 26.598 1.385 µs 0.1861 3.151

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 -14.839 15.262 23.866 50.899 93.924 113.820 203.645 70.058 98.558 22.408 54.256 µs 0.6708 3.487

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 -43.159 -17.207 -8.379 18.245 60.644 79.358 166.032 69.023 96.565 21.958 21.625 µs 0.6701 3.517

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 -34.153 2.233 12.821 44.949 88.823 107.305 205.711 76.002 105.072 23.515 47.537 µs 0.4884 3.344

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 -55.156 -13.948 -4.416 22.262 64.028 83.112 185.439 68.444 97.060 21.806 25.467 µs 0.6546 3.56

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 -19.456 22.457 36.258 71.803 117.143 136.753 217.385 80.885 114.296 24.928 74.066 µs 0.3813 3.272

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 1.160 3.557 6.083 29.282 63.569 82.753 808.100 57.486 79.196 20.361 31.121 µs 5.177 114.6

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 10.0.50.100

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 0.416 1.605 2.506 11.340 36.770 52.247 873.335 34.264 50.642 13.301 14.474 µs 14.57 756.3

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 10.0.50.20

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 0.000 5.284 8.396 20.298 46.406 63.428 650.819 38.010 58.144 13.297 22.999 µs 7.122 248.9

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 0.000 3.774 5.960 20.404 49.129 65.995 848.781 43.169 62.221 15.562 23.041 µs 12.03 527.5

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 10.0.50.40

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 0.000 5.109 7.676 18.526 45.117 61.333 845.152 37.441 56.224 14.474 21.542 µs 15.49 738.8

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.



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 0.002 0.008 0.011 0.024 0.048 0.063 10.265 0.037 0.056 0.066 0.026 ms 149 2.309e+04

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 -5.144 -3.390 -2.726 -1.471 -0.390 0.080 1.390 2.336 3.470 0.723 -1.512 ppm -0.2762 3.408
Local Clock Time Offset -97.493 -55.069 -42.440 1.372 46.313 66.236 163.209 88.753 121.305 26.597 1.385 µs 0.1861 3.151
Local RMS Frequency Jitter 0.099 0.213 0.337 0.609 0.909 1.059 1.717 0.572 0.846 0.173 0.615 ppm 0.2399 3.533
Local RMS Time Jitter 4.984 12.989 19.866 34.661 50.235 58.539 86.796 30.369 45.550 9.171 34.858 µs 0.1594 3.565
Server Jitter 10.0.50.10 1.160 3.557 6.083 29.282 63.569 82.753 808.100 57.486 79.196 20.361 31.121 µs 5.177 114.6
Server Jitter 10.0.50.100 0.416 1.605 2.506 11.340 36.770 52.247 873.335 34.264 50.642 13.301 14.474 µs 14.57 756.3
Server Jitter 10.0.50.20 0.000 5.284 8.396 20.298 46.406 63.428 650.819 38.010 58.144 13.297 22.999 µs 7.122 248.9
Server Jitter 10.0.50.30 0.000 3.774 5.960 20.404 49.129 65.995 848.781 43.169 62.221 15.562 23.041 µs 12.03 527.5
Server Jitter 10.0.50.40 0.000 5.109 7.676 18.526 45.117 61.333 845.152 37.441 56.224 14.474 21.542 µs 15.49 738.8
Server Jitter 10.0.50.50 0.002 0.008 0.011 0.024 0.048 0.063 10.265 0.037 0.056 0.066 0.026 ms 149 2.309e+04
Server Offset 10.0.50.10 -97.494 -55.070 -42.441 1.373 46.314 66.237 163.210 88.755 121.307 26.598 1.385 µs 0.1861 3.151
Server Offset 10.0.50.100 -14.839 15.262 23.866 50.899 93.924 113.820 203.645 70.058 98.558 22.408 54.256 µs 0.6708 3.487
Server Offset 10.0.50.20 -43.159 -17.207 -8.379 18.245 60.644 79.358 166.032 69.023 96.565 21.958 21.625 µs 0.6701 3.517
Server Offset 10.0.50.30 -34.153 2.233 12.821 44.949 88.823 107.305 205.711 76.002 105.072 23.515 47.537 µs 0.4884 3.344
Server Offset 10.0.50.40 -55.156 -13.948 -4.416 22.262 64.028 83.112 185.439 68.444 97.060 21.806 25.467 µs 0.6546 3.56
Server Offset 10.0.50.50 -19.456 22.457 36.258 71.803 117.143 136.753 217.385 80.885 114.296 24.928 74.066 µs 0.3813 3.272
Temp ZONE0 53.000 54.000 55.000 62.000 63.000 63.000 64.000 8.000 9.000 2.105 61.894 °C
Temp ZONE1 54.000 55.000 56.000 64.000 65.000 65.000 66.000 9.000 10.000 2.136 63.247 °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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