Cost effective time servers

Fri Jun 21 11:23:32 UTC 2019

On 2019-06-21 14:19, Niels Bakker wrote:
> * jay at west.net (Jay Hennigan) [Fri 21 Jun 2019, 05:19 CEST]:
>> On 6/20/19 07:39, David Bass wrote:
>>> What are folks using these days for smaller organizations, that need 
>>> to dole out time from an internal source?
>> 
>> If you want to go really cheap and don't value your time, but do value 
>> knowing the correct time, a GPS receiver with a USB interface and a 
>> Raspberry Pi would do the trick.
> 
> Have you tried this?  Because I have, and it's absolutely terrible.
> GPS doesn't give you the correct time, it's supposed to give you a
> good 1pps clock discipline against which you can measure your device's
> internal clock and adjust accordingly for drift due to it not being
> Cesium-based, influenced by room temperature etc.
> 
> You're unlikely to get the 1pps signal across USB, and even then
> there'll likely be significant latencies in the USB stack compared to
> the serial interface that these setups traditionally use.

I think it depends on recipe you are using.
Raspberry have low latency GPIO, and some receivers have 1pps output.
https://www.satsignal.eu/ntp/Raspberry-Pi-NTP.html