NTPsec

NTP0: x86 SBC, NTPSec, NTP-disciplined (stratum 2)
Six Hour - August 01, 2026 06:00 UTC

Report generated: Sat Aug 1 06:01:22 2026 UTC
Start Time: Sat Aug 1 00:01:22 2026 UTC
End Time: Sat Aug 1 06:01:22 2026 UTC
Report Period: 0.2 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 -464.707 -31.019 -20.126 0.259 20.742 29.337 749.773 40.868 60.356 24.182 0.272 µs 7.967 491.5
Local Clock Frequency Offset -28.170 -2.042 -1.642 -1.042 -0.522 -0.251 2.707 1.119 1.791 0.734 -1.071 ppm -24.56 852

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 7.794 9.449 11.395 17.263 26.207 122.302 444.663 14.812 112.853 26.880 20.369 µs 11.18 144.2

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 0.116 0.154 0.199 0.296 0.465 2.660 10.338 0.266 2.505 0.616 0.370 ppm 11.12 141.4

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 -464.707 -31.019 -20.126 0.259 20.742 29.337 749.773 40.868 60.356 24.182 0.272 µs 7.967 491.5

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 -28.170 -2.042 -1.642 -1.042 -0.522 -0.251 2.707 1.119 1.791 0.734 -1.071 ppm -24.56 852
Temp ZONE0 56.000 56.000 57.000 57.000 58.000 58.000 58.000 1.000 2.000 0.308 57.071 °C
Temp ZONE1 57.000 57.000 57.000 58.000 59.000 59.000 59.000 2.000 2.000 0.679 57.900 °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 -482.196 -31.079 -20.151 0.260 20.743 29.338 749.774 40.894 60.417 26.158 0.072 µs 3.644 408.6

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 -15.705 -5.716 1.653 48.290 76.086 214.027 1,023.778 74.433 219.743 39.875 46.313 µs 8.325 165.1

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 -60.929 -48.118 -37.450 -2.112 31.081 180.299 550.763 68.531 228.417 36.237 0.113 µs 4.95 47.75

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 -81.384 -73.603 -63.635 -11.882 28.964 166.968 652.935 92.599 240.571 41.029 -12.100 µs 4.719 56.57

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 -44.362 -28.361 -9.521 44.496 87.158 197.823 1,123.186 96.679 226.184 45.424 45.175 µs 7.471 141.7

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 5.164 9.767 12.932 27.087 45.730 67.898 708.568 32.798 58.131 34.607 30.392 µs 13.72 234.9

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 10.0.50.100

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 1.058 2.058 3.160 10.003 26.119 38.560 772.011 22.959 36.502 29.453 13.100 µs 18.57 412.1

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 0.003 0.008 0.012 0.023 0.042 0.056 15.714 0.030 0.047 0.458 0.040 ms 34.01 1164

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 6.141 8.986 12.993 26.447 46.285 56.452 734.367 33.292 47.466 31.315 29.337 µs 17.32 359.3

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 3.031 6.153 9.499 26.301 50.251 63.074 663.481 40.752 56.921 27.671 28.999 µs 14.69 289.4

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.



Summary


Percentiles...... Ranges...... Skew- Kurt-
Name Min1%5%50%95% 99%Max   90%98%StdDev  MeanUnits nessosis
Local Clock Frequency Offset -28.170 -2.042 -1.642 -1.042 -0.522 -0.251 2.707 1.119 1.791 0.734 -1.071 ppm -24.56 852
Local Clock Time Offset -464.707 -31.019 -20.126 0.259 20.742 29.337 749.773 40.868 60.356 24.182 0.272 µs 7.967 491.5
Local RMS Frequency Jitter 0.116 0.154 0.199 0.296 0.465 2.660 10.338 0.266 2.505 0.616 0.370 ppm 11.12 141.4
Local RMS Time Jitter 7.794 9.449 11.395 17.263 26.207 122.302 444.663 14.812 112.853 26.880 20.369 µs 11.18 144.2
Server Jitter 10.0.50.10 5.164 9.767 12.932 27.087 45.730 67.898 708.568 32.798 58.131 34.607 30.392 µs 13.72 234.9
Server Jitter 10.0.50.100 1.058 2.058 3.160 10.003 26.119 38.560 772.011 22.959 36.502 29.453 13.100 µs 18.57 412.1
Server Jitter 10.0.50.20 0.003 0.008 0.012 0.023 0.042 0.056 15.714 0.030 0.047 0.458 0.040 ms 34.01 1164
Server Jitter 10.0.50.40 6.141 8.986 12.993 26.447 46.285 56.452 734.367 33.292 47.466 31.315 29.337 µs 17.32 359.3
Server Jitter 10.0.50.50 3.031 6.153 9.499 26.301 50.251 63.074 663.481 40.752 56.921 27.671 28.999 µs 14.69 289.4
Server Offset 10.0.50.10 -482.196 -31.079 -20.151 0.260 20.743 29.338 749.774 40.894 60.417 26.158 0.072 µs 3.644 408.6
Server Offset 10.0.50.100 -15.705 -5.716 1.653 48.290 76.086 214.027 1,023.778 74.433 219.743 39.875 46.313 µs 8.325 165.1
Server Offset 10.0.50.20 -60.929 -48.118 -37.450 -2.112 31.081 180.299 550.763 68.531 228.417 36.237 0.113 µs 4.95 47.75
Server Offset 10.0.50.40 -81.384 -73.603 -63.635 -11.882 28.964 166.968 652.935 92.599 240.571 41.029 -12.100 µs 4.719 56.57
Server Offset 10.0.50.50 -44.362 -28.361 -9.521 44.496 87.158 197.823 1,123.186 96.679 226.184 45.424 45.175 µs 7.471 141.7
Temp ZONE0 56.000 56.000 57.000 57.000 58.000 58.000 58.000 1.000 2.000 0.308 57.071 °C
Temp ZONE1 57.000 57.000 57.000 58.000 59.000 59.000 59.000 2.000 2.000 0.679 57.900 °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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