NTPsec

NTP4: SecureSync, Rubidium, NTP (Classic)
Seven Day - May 01, 2026 20:00 UTC

Report generated: Fri May 1 20:14:11 2026 UTC
Start Time: Fri Apr 24 20:14:09 2026 UTC
End Time: Fri May 1 20:14:09 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, Undisciplined, NTPSec
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 -17.000 -1.000 -1.000 0.000 0.998 1.000 73.998 1.998 2.000 0.708 -0.000 µs 34.1 2559
Local Clock Frequency Offset 89.666 89.677 89.684 89.700 89.716 89.721 89.743 0.032 0.044 0.0095 89.700 ppm -0.1631 3.067

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 0.954 0.955 0.958 0.970 1.112 1.603 40.437 0.154 0.648 0.777 1.043 µs 20.45 571.7

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 0.016 0.061 0.098 0.199 0.290 0.484 12.779 0.192 0.423 0.270 0.216 ppb 18.63 490.6

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 -17.000 -1.000 -1.000 0.000 0.998 1.000 73.998 1.998 2.000 0.708 -0.000 µs 34.1 2559

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 89.666 89.677 89.684 89.700 89.716 89.721 89.743 0.032 0.044 0.0095 89.700 ppm -0.1631 3.067
Temp BOARD 58.000 58.000 58.000 58.750 59.880 59.880 59.880 1.880 1.880 0.379 58.775 °C
Temp CPU 58.000 58.000 58.000 59.120 59.880 59.880 59.880 1.880 1.880 0.422 59.069 °C
Temp OSC 48.270 48.450 48.530 48.760 48.990 49.060 49.230 0.460 0.610 0.138 48.756 °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 14.000 17.000 18.000 21.000 25.000 26.000 28.000 7.000 9.000 1.888 21.455 nSat 0.1048 2.833
TDOP 0.180 0.180 0.190 0.200 0.200 0.210 0.220 0.010 0.030 0.006 0.196 -0.1008 2.688

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 10.0.0.241

peer offset 10.0.0.241 plot

Percentiles...... Ranges...... Skew- Kurt-
Name Min1%5%50%95% 99%Max   90%98%StdDev  MeanUnits nessosis
Server Offset 10.0.0.241 -606.148 13.489 23.918 42.379 58.743 66.153 680.229 34.825 52.664 23.758 43.085 µs 1.431 363.9

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 10.0.0.242

peer offset 10.0.0.242 plot

Percentiles...... Ranges...... Skew- Kurt-
Name Min1%5%50%95% 99%Max   90%98%StdDev  MeanUnits nessosis
Server Offset 10.0.0.242 -613.553 6.512 18.904 40.029 55.640 61.696 550.493 36.736 55.184 17.503 39.577 µs -2.776 348.4

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 10.0.0.90

peer offset 10.0.0.90 plot

Percentiles...... Ranges...... Skew- Kurt-
Name Min1%5%50%95% 99%Max   90%98%StdDev  MeanUnits nessosis
Server Offset 10.0.0.90 -526.134 7.487 13.231 26.647 47.329 55.511 531.942 34.098 48.024 14.725 28.167 µs 7.68 423.8

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 -11.910 9.584 11.166 34.669 42.284 43.547 109.295 31.118 33.963 8.207 32.782 µs -1.433 5.371

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 -109.812 31.537 44.582 66.051 98.628 106.240 297.338 54.046 74.703 15.908 68.029 µs 0.2617 9.887

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 -17.000 -1.001 -1.000 -0.001 0.999 1.000 73.999 1.999 2.001 0.708 -0.001 µs 34.09 2557

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 10.0.0.241

peer jitter 10.0.0.241 plot

Percentiles...... Ranges...... Skew- Kurt-
Name Min1%5%50%95% 99%Max   90%98%StdDev  MeanUnits nessosis
Server Jitter 10.0.0.241 0.001 0.008 0.012 0.025 0.382 2.441 9.716 0.370 2.432 0.422 0.113 ms 7.276 70.17

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 10.0.0.242

peer jitter 10.0.0.242 plot

Percentiles...... Ranges...... Skew- Kurt-
Name Min1%5%50%95% 99%Max   90%98%StdDev  MeanUnits nessosis
Server Jitter 10.0.0.242 0.001 0.008 0.011 0.023 0.578 2.449 16.514 0.567 2.441 0.651 0.144 ms 12.39 213.3

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 10.0.0.90

peer jitter 10.0.0.90 plot

Percentiles...... Ranges...... Skew- Kurt-
Name Min1%5%50%95% 99%Max   90%98%StdDev  MeanUnits nessosis
Server Jitter 10.0.0.90 0.001 0.008 0.011 0.025 0.318 1.889 12.490 0.307 1.881 0.421 0.098 ms 11.85 201.9

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 0.954 1.301 1.989 7.341 28.404 32.537 591.477 26.415 31.236 14.441 9.837 µs 28.01 1094

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 0.954 4.013 5.688 14.261 39.140 52.873 733.578 33.452 48.860 15.887 19.289 µs 13.36 482.6

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.



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 1.133 1.362 74.289 0.179 0.408 0.795 1.003 µs 36.11 1872

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 89.666 89.677 89.684 89.700 89.716 89.721 89.743 0.032 0.044 0.0095 89.700 ppm -0.1631 3.067
Local Clock Time Offset -17.000 -1.000 -1.000 0.000 0.998 1.000 73.998 1.998 2.000 0.708 -0.000 µs 34.1 2559
Local RMS Frequency Jitter 0.016 0.061 0.098 0.199 0.290 0.484 12.779 0.192 0.423 0.270 0.216 ppb 18.63 490.6
Local RMS Time Jitter 0.954 0.955 0.958 0.970 1.112 1.603 40.437 0.154 0.648 0.777 1.043 µs 20.45 571.7
Refclock Offset 127.127.45.0 -17.000 -1.001 -1.000 -0.001 0.999 1.000 73.999 1.999 2.001 0.708 -0.001 µs 34.09 2557
Refclock RMS Jitter 127.127.45.0 0.954 0.954 0.954 0.954 1.133 1.362 74.289 0.179 0.408 0.795 1.003 µs 36.11 1872
Server Jitter 10.0.0.241 0.001 0.008 0.012 0.025 0.382 2.441 9.716 0.370 2.432 0.422 0.113 ms 7.276 70.17
Server Jitter 10.0.0.242 0.001 0.008 0.011 0.023 0.578 2.449 16.514 0.567 2.441 0.651 0.144 ms 12.39 213.3
Server Jitter 10.0.0.90 0.001 0.008 0.011 0.025 0.318 1.889 12.490 0.307 1.881 0.421 0.098 ms 11.85 201.9
Server Jitter 10.0.50.100 0.954 1.301 1.989 7.341 28.404 32.537 591.477 26.415 31.236 14.441 9.837 µs 28.01 1094
Server Jitter 10.0.50.50 0.954 4.013 5.688 14.261 39.140 52.873 733.578 33.452 48.860 15.887 19.289 µs 13.36 482.6
Server Offset 10.0.0.241 -606.148 13.489 23.918 42.379 58.743 66.153 680.229 34.825 52.664 23.758 43.085 µs 1.431 363.9
Server Offset 10.0.0.242 -613.553 6.512 18.904 40.029 55.640 61.696 550.493 36.736 55.184 17.503 39.577 µs -2.776 348.4
Server Offset 10.0.0.90 -526.134 7.487 13.231 26.647 47.329 55.511 531.942 34.098 48.024 14.725 28.167 µs 7.68 423.8
Server Offset 10.0.50.100 -11.910 9.584 11.166 34.669 42.284 43.547 109.295 31.118 33.963 8.207 32.782 µs -1.433 5.371
Server Offset 10.0.50.50 -109.812 31.537 44.582 66.051 98.628 106.240 297.338 54.046 74.703 15.908 68.029 µs 0.2617 9.887
TDOP 0.180 0.180 0.190 0.200 0.200 0.210 0.220 0.010 0.030 0.006 0.196 -0.1008 2.688
Temp BOARD 58.000 58.000 58.000 58.750 59.880 59.880 59.880 1.880 1.880 0.379 58.775 °C
Temp CPU 58.000 58.000 58.000 59.120 59.880 59.880 59.880 1.880 1.880 0.422 59.069 °C
Temp OSC 48.270 48.450 48.530 48.760 48.990 49.060 49.230 0.460 0.610 0.138 48.756 °C
nSats 14.000 17.000 18.000 21.000 25.000 26.000 28.000 7.000 9.000 1.888 21.455 nSat 0.1048 2.833
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 10.0.50.55. 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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