[time-nuts] RaspberryPi and RADclock

David J Taylor david-taylor at blueyonder.co.uk
Sat Dec 15 07:07:04 UTC 2012


From: paul swed

Thanks.
I really like the idea that a Rassberry Pi could be a time server. Maybe
enough to get me going.
Thanks
===============================

Paul,

I wrote up my experiences with the Raspberry Pi as a standard NTP server 
here:

  http://www.satsignal.eu/ntp/Raspberry-Pi-NTP.html

and the performance can be seen here:

  http://www.satsignal.eu/ntp/Raspberry-Pi-NTP.html#current
  http://www.satsignal.eu/mrtg/performance_ntp-pn.php

Interestingly, the second RPi card is doing better than the first, and it 
does /not/ have gpsd installed, so relying on the LAW/WAN for its source of 
coarse seconds.   But it has a timekeeping GPS and a slightly better located 
antenna as well - both antennas are indoors and some drop-outs show as 
spikes on RasPi-1.  No gpsd appears to mean less CPU load.  Compare:

  http://www.satsignal.eu/mrtg/performance_raspi-1.php
  http://www.satsignal.eu/mrtg/performance_raspi-2.php

It looks like sub-microsecond might be possible in a temperature-controlled 
environment, as the main drift seems to be at 05:30 when the heating turns 
on:

  http://www.satsignal.eu/mrtg/performance_ntp.php?period=week

Raspberry Pi 2 was only switched to GPS from LAN-only sync a few days ago.

Cheers,
David
-- 
SatSignal Software - Quality software written to your requirements
Web: http://www.satsignal.eu
Email: david-taylor at blueyonder.co.uk 




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