NTPsec

NTP4: SecureSync, Rubidium, NTP (Classic)
Six Hour - August 01, 2026 06:00 UTC

Report generated: Sat Aug 1 06:01:43 2026 UTC
Start Time: Sat Aug 1 00:01:43 2026 UTC
End Time: Sat Aug 1 06:01:43 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

NTP4 is a Safran SecureSync 1200 appliance with a Rubidium oscillator and u-blox timing GNSS receiver. It is used as a highly stable atomic reference clock for the network.

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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 -1,920.263 -1.000 -1.000 0.000 42.998 190.998 528.998 43.998 191.998 56.098 6.894 µs -19.17 726.5
Local Clock Frequency Offset 108.265 110.806 114.618 115.755 115.764 115.766 115.768 1.146 4.960 0.821 115.561 ppm -5.55 36.61

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 0.955 0.958 0.960 0.972 2.465 303.025 1,001.027 1.505 302.067 65.761 9.339 µs 10.29 120

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 0.052 0.099 0.128 0.227 25.684 754.310 2,652.020 25.556 754.211 169.552 22.789 ppb 10.52 126.5

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 -1,920.263 -1.000 -1.000 0.000 42.998 190.998 528.998 43.998 191.998 56.098 6.894 µs -19.17 726.5

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 108.265 110.806 114.618 115.755 115.764 115.766 115.768 1.146 4.960 0.821 115.561 ppm -5.55 36.61
Temp BOARD 58.000 58.000 58.000 59.000 59.880 59.880 59.880 1.880 1.880 0.479 59.039 °C
Temp CPU 58.000 59.000 59.120 59.380 59.500 59.620 59.750 0.380 0.620 0.162 59.322 °C
Temp OSC 48.780 48.820 48.850 48.970 49.110 49.140 49.160 0.260 0.320 0.078 48.971 °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.



Local GPS

local gps plot

Percentiles...... Ranges...... Skew- Kurt-
Name Min1%5%50%95% 99%Max   90%98%StdDev  MeanUnits nessosis
nSats 19.000 19.000 20.000 23.000 26.000 28.000 28.000 6.000 9.000 1.762 22.992 nSat 0.37 3.701
TDOP 0.180 0.180 0.180 0.190 0.200 0.200 0.200 0.020 0.020 0.005 0.191 0.1539 4.186

Local GPS. The Time Dilution of Precision (TDOP) is plotted in blue. The number of visible satellites (nSat) is plotted in red.

TDOP is field 3, and nSats is field 4, from the gpsd log file. The gpsd log file is created by the ntploggps program.

TDOP is a dimensionless error factor. Smaller numbers are better. TDOP ranges from 1 (ideal), 2 to 5 (good), to greater than 20 (poor). Some GNSS receivers report TDOP less than one which is theoretically impossible.



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 10.0.50.100

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 -35.800 6.082 11.136 40.912 68.282 187.645 249.326 57.146 181.563 27.791 40.640 µs 4.184 27.37

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 -28.745 -17.859 -7.278 5.248 23.328 33.661 56.532 30.606 51.520 9.871 6.527 µs 0.6616 5.352

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 10.0.50.200

peer offset 10.0.50.200 plot

Percentiles...... Ranges...... Skew- Kurt-
Name Min1%5%50%95% 99%Max   90%98%StdDev  MeanUnits nessosis
Server Offset 10.0.50.200 -41.831 -25.695 -11.389 29.027 51.478 60.636 70.665 62.867 86.331 18.526 25.173 µs -0.6998 3.516

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 -24.057 -11.876 -1.640 26.702 65.453 173.201 220.867 67.093 185.077 30.167 27.025 µs 3.634 20.17

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 10.661 17.439 34.284 48.903 60.358 66.389 76.154 26.074 48.950 8.623 48.419 µs -0.8296 5.723

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.



Refclock Offset 127.127.45.0

peer offset 127.127.45.0 plot

Percentiles...... Ranges...... Skew- Kurt-
Name Min1%5%50%95% 99%Max   90%98%StdDev  MeanUnits nessosis
Refclock Offset 127.127.45.0 -1,920.264 -1.001 -1.000 0.000 45.000 190.999 528.999 46.000 192.000 56.132 6.927 µs -19.17 726

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

Closer to 0s is better. An ideal system would be a horizontal line at 0s. Typical 90% ranges may be: local serial GPS 200 ms; local PPS 20µs.

Clock Offset is field 5 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 10.0.50.100

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 0.954 1.006 1.356 3.048 31.206 37.687 239.248 29.850 36.681 18.004 9.620 µs 8.448 100

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 4.894 6.761 11.133 22.591 42.865 48.724 70.652 31.732 41.963 10.003 24.507 µs 0.8438 3.992

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 10.0.50.200

peer jitter 10.0.50.200 plot

Percentiles...... Ranges...... Skew- Kurt-
Name Min1%5%50%95% 99%Max   90%98%StdDev  MeanUnits nessosis
Server Jitter 10.0.50.200 4.888 5.674 7.049 16.534 48.088 60.850 78.242 41.039 55.176 12.756 20.422 µs 1.532 5.589

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 1.344 1.760 2.357 7.416 34.340 45.238 239.276 31.983 43.478 20.476 13.260 µs 7.316 72.74

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 4.256 4.873 5.648 11.784 36.776 43.986 53.452 31.128 39.113 9.677 14.851 µs 1.505 4.673

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.



Refclock RMS Jitter 127.127.45.0

peer jitter 127.127.45.0 plot

Percentiles...... Ranges...... Skew- Kurt-
Name Min1%5%50%95% 99%Max   90%98%StdDev  MeanUnits nessosis
Refclock RMS Jitter 127.127.45.0 0.954 0.954 0.954 0.954 4.174 21.462 2,187.263 3.220 20.508 83.318 6.410 µs 19.42 414.2

The RMS Jitter of a local refclock. 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 108.265 110.806 114.618 115.755 115.764 115.766 115.768 1.146 4.960 0.821 115.561 ppm -5.55 36.61
Local Clock Time Offset -1,920.263 -1.000 -1.000 0.000 42.998 190.998 528.998 43.998 191.998 56.098 6.894 µs -19.17 726.5
Local RMS Frequency Jitter 0.052 0.099 0.128 0.227 25.684 754.310 2,652.020 25.556 754.211 169.552 22.789 ppb 10.52 126.5
Local RMS Time Jitter 0.955 0.958 0.960 0.972 2.465 303.025 1,001.027 1.505 302.067 65.761 9.339 µs 10.29 120
Refclock Offset 127.127.45.0 -1,920.264 -1.001 -1.000 0.000 45.000 190.999 528.999 46.000 192.000 56.132 6.927 µs -19.17 726
Refclock RMS Jitter 127.127.45.0 0.954 0.954 0.954 0.954 4.174 21.462 2,187.263 3.220 20.508 83.318 6.410 µs 19.42 414.2
Server Jitter 10.0.50.100 0.954 1.006 1.356 3.048 31.206 37.687 239.248 29.850 36.681 18.004 9.620 µs 8.448 100
Server Jitter 10.0.50.20 4.894 6.761 11.133 22.591 42.865 48.724 70.652 31.732 41.963 10.003 24.507 µs 0.8438 3.992
Server Jitter 10.0.50.200 4.888 5.674 7.049 16.534 48.088 60.850 78.242 41.039 55.176 12.756 20.422 µs 1.532 5.589
Server Jitter 10.0.50.40 1.344 1.760 2.357 7.416 34.340 45.238 239.276 31.983 43.478 20.476 13.260 µs 7.316 72.74
Server Jitter 10.0.50.50 4.256 4.873 5.648 11.784 36.776 43.986 53.452 31.128 39.113 9.677 14.851 µs 1.505 4.673
Server Offset 10.0.50.100 -35.800 6.082 11.136 40.912 68.282 187.645 249.326 57.146 181.563 27.791 40.640 µs 4.184 27.37
Server Offset 10.0.50.20 -28.745 -17.859 -7.278 5.248 23.328 33.661 56.532 30.606 51.520 9.871 6.527 µs 0.6616 5.352
Server Offset 10.0.50.200 -41.831 -25.695 -11.389 29.027 51.478 60.636 70.665 62.867 86.331 18.526 25.173 µs -0.6998 3.516
Server Offset 10.0.50.40 -24.057 -11.876 -1.640 26.702 65.453 173.201 220.867 67.093 185.077 30.167 27.025 µs 3.634 20.17
Server Offset 10.0.50.50 10.661 17.439 34.284 48.903 60.358 66.389 76.154 26.074 48.950 8.623 48.419 µs -0.8296 5.723
TDOP 0.180 0.180 0.180 0.190 0.200 0.200 0.200 0.020 0.020 0.005 0.191 0.1539 4.186
Temp BOARD 58.000 58.000 58.000 59.000 59.880 59.880 59.880 1.880 1.880 0.479 59.039 °C
Temp CPU 58.000 59.000 59.120 59.380 59.500 59.620 59.750 0.380 0.620 0.162 59.322 °C
Temp OSC 48.780 48.820 48.850 48.970 49.110 49.140 49.160 0.260 0.320 0.078 48.971 °C
nSats 19.000 19.000 20.000 23.000 26.000 28.000 28.000 6.000 9.000 1.762 22.992 nSat 0.37 3.701
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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