NIST NTP servers

[lowen at pari.edu (Lamar Owen)]

On 05/11/2016 09:46 PM, Josh Reynolds wrote:
> maybe try [setting up an NTP server] with an odroid?
>
...

I have several ODroid C2's, and the first thing to note about them is 
that there is no RTC at all.  Also, the oscillator is just a 
garden-variety non-temperature-compensated quartz crystal, and not 
necessarily a very precise one, either (precise quartz oscillators can 
cost more than the whole ODroid board costs).  The XU4 and other ODroid 
devices make nice single-board ARM computers, but have pretty ratty 
oscillator precision.

You really have to have at least a temperature compensated quartz 
crystal oscillator (TCXO) to even begin to think about an NTP server, 
for anything but the most rudimentary of timing.  Ovenized quartz 
oscillators (OCXO) and rubidium standards are the next step up, and most 
reasonably good GPS-disciplined clocks have at least an ovenized quartz 
oscillator module (the Agilent Z3816 and kin are of this type).