[lightswitch05]

You can see for yourself the level of accuracy in the ntpviz output. Notice the units of measurement on the graphs:

* Clayface: https://www.developerdan.com/ntp/#./clayface/7-days/

* Catwoman: https://www.developerdan.com/ntp/#./catwoman/7-days/

That Wikipedia quote should mention temperature! Temperature variations have a big impact at this level of accuracy. These really cheap GPS receivers do not have temperature adjusted clocks. Unfortunately my server closet (this is just a hobby) does not have well regulated temperature, so you can see the impact of temperature on the clock accuracy. Also, I found if I start running a bunch of stuff on these computers - that makes the CPU heat up, which also affects the jitter. If you really want high-precision, you'll have to shell out some extra cash then I did: https://www.sparkfun.com/products/18774

[hcfman]

rtk gnsses really rock. I would to save up for one for next year :)