[ntp:questions] time delta between clients
David J Taylor
david-taylor at blueyonder.not-this-bit.nor-this-bit.co.uk
Thu Dec 13 07:55:44 UTC 2007
Rick Jones wrote:
[]
> I suppose I could also try to see if I can get the powers that be to
> spring for a GPS18 and see if I can indeed get signal in the machine
> room(s) of interest.
>
> Speaking of which, I was just at the garmin website, and seems they
> now have a GPS18 5HZ in addition to the regular GPS18. Is there any
> benefit to the extra four pulses per second?
>
> rick jones
Rick,
I have found that, compared to recent GPS receivers, the GPS-18 is not
very sensitive. For example, I needed to mount the unit outside my
window:
http://www.david-taylor.myby.co.uk/ntp/FreeBSD-GPS-PPS.htm
facing south, to get any signal, whereas my GPSmap 60CSx works fine
/inside/ the same room. Even outside the window, the approximately
180-degree sky view resulted in some loss of sync, and I now have the
GPS-18 on the roof which has a 30 degree slope to the west. Not ideal,
but better than before.
There is no advantage to the 5Hz unit with the present NTP implementation.
Cheers,
David
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