[ntp:questions] GPS/PPS and "enable calibrate"

David Taylor david-taylor at blueyonder.co.uk.invalid
Fri Sep 6 11:09:43 UTC 2013


On 05/09/2013 21:00, Horvath Bob-BHORVAT1 wrote:
[]
> Hi,
> this runs perfectly for me:
> <http://open.konspyre.org/blog/2012/10/18/raspberry-pi-time-server/>.
>
> OK, maybe I'll have to try that image.
>
> In general though, when it comes to this line...
>
>    fudge 127.127.20.0 flag1 1 time2 0.496
>
> ... how do you know what value to set for time2?
>
> Did you got through the instructions here?
>
> http://www.eecis.udel.edu/~mills/ntp/html/drivers/driver20.html
>
> ... or are you using 0.496 - what is shown on the http://open.konspyre.org/blog/2012/10/18/raspberry-pi-time-server/ ?
>
>
>
> Bob

No need to change the Kernel,Bob.  There's a program which does /not/ 
require you to change the OS - it runs the PPS collection in user-mode 
rather than kernel-mode, and the performance is only a shade worse than 
the kernel-mode version:

Program:
   http://vanheusden.com/time/rpi_gpio_ntp/

Using:
   http://www.satsignal.eu/ntp/Raspberry-Pi-NTP.html#user-mode

Performance:
   http://www.satsignal.eu/mrtg/performance_raspi-4.php

All my Raspberry Pi experiments with different NTP versions and 
different GPS receivers are here:

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

so I hope you find something of interest there.

-- 
Cheers,
David
Web: http://www.satsignal.eu



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