On 2016-05-13 14:12, Lamar Owen wrote:
On 05/11/2016 09:46 PM, Josh Reynolds wrote:
maybe try [setting up an NTP server] with an odroid?
...
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.
There are WWVB clocks that try to sync nightly. Many of them don't even
have a second indicator, but they give reliable time to the minute. NTP
is a lot better than this as it continuously disciplines the clock
instead of just lining it up once a day, but we're talking about doing
this over the internet where we measure latency in milliseconds. If
you're working down at the picosecond level you will probably not be
using NTP to distribute your clock signal. Running an NTP client
against pool servers is a lot better than not running it at all, but
running it against a fancy local server with a GPSDO hooked up to it is
only marginally better than the pool servers.
It all depends on what you want to do but a cheap ARM or Intel Atom
computer works well for an NTP server (remember millisecond level
accuracy). If you can afford to build a secure bunker with armed guards
and redundant everything for your time server that's good, but a few RPi
style computers with GPS hats are almost as good, and you can buy a lot
of them for very little money..
-Laszlo
