unruh wrote:
On 2012-02-23, Alby VA <alb...@empire.org> wrote:
On Feb 23, 4:29?pm, unruh <un...@invalid.ca> wrote:
No, that is a very typical figure for the frequency offset. Remember
that the crystals used to control the timing in computers are not
supposed to be terribly accurate. (They are chosen to be cheap, not
great).
It is because such frequency offsets exist that ntp was invented to
correct.
When you say "crystals used to control the timing in computers",
are you referring to the parts that make up my actual FreeBSD
Server (ie: Motherboard)? Or Parts in the GPS Device (ie: Sure Elec.
GPS)?
On your motherboard.
Or in the Satellites receiving the GPS signal?
I'm just trying to gauge, what hardware should be looking to obtain
to
improve that frequency offset. Or is it a moot point unless I'm going
to
invest in some high dollar atomic clock?
An atomic clock.
Or better yet, can I buy quality crystals from DigiKey and do some
soldering in whatever devices that need crystal upgrading?
No.
And why do you care? As I said this is waht ntp was invented for. It is
doing its job.
When I started using ntpd it didn't work with some of my
systems as the clocks were too far out, >> 50ppm, and/or
too temperature sensitive. Some of my motherboards had a
3-pin jumper already fitted so that an external clock
source could be connected.
One of my desktop systems, p4-2667, has just taken two
days to get to an offset of under 2 ms after a kernel
change. I suspect because that coincided with the hottest
day in February since 1998. All my pcs were affected
except the one connected to PPS from a Sure GPS. The one
with an MSF source, no PPS, was also fighting to keep sync.
David
Note that even all of the time standard labs around the world use
programs like ntp to track their frequency offsets.
And all atomic clocks have them.
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