[time] GPS Time Server Survey

Chris Kuethe chris.kuethe
Thu Apr 24 22:32:49 UTC 2008


On Thu, Apr 24, 2008 at 3:20 PM, Jan Hoevers <ml.janhoevers at xs4all.nl> wrote:
>  No way you can maintain that kind of accuracy with "a good crystal",
>  even an oven controlled one would not do the job.  And the average pool
>  member will not sell his home to buy a cesium osc.

they're not that expensive. as i write this, there's one on ebay under
$2.5k. rubidiums are easily had under a thousand; the bare physics
package can be had for a couple hundred.

>  What problem are you trying to solve anyway?  We serve time over the
>  internet, typically with an accuracy of 5 - 50 ms.  That is
>  milliseconds, not nanoseconds, not even microseconds.

"because i can"

note that i was the one who observed (twice) that there's ethernet
(and possibly ADSL) between any of my clients thereby seriously
impacting my accuracy.

>  We have no need for a 30 ns reference, as it would be a million times as
>  accurate as the service we can offer to the pool users.

but that doesn't stop me from wanting a 30ns reference.

>  I do believe the pool will need more accuracy in the future, but right
>  now the network is the bottleneck, not the time reference.

yes, i think this morning we all saw that the network sucks.

-- 
GDB has a 'break' feature; why doesn't it have 'fix' too?



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