[ntp:questions] Isolated Network Drift Problem

Cal Webster cwebster at ec.rr.com
Tue Nov 25 23:22:28 UTC 2008


On Tue, 2008-11-25 at 17:52 -0500, Richard B. Gilbert wrote:
> Steve Kostecke wrote:
> > On 2008-11-25, Cal Webster <cwebster at ec.rr.com> wrote:
> > 
> >> ... We'd have to run a long cable [to the GPS18LVC] though,
> >> the computer lab has no windows and the roof is the most logical place
> >> to put an antenna. I don't think USB will handle that much line loss.
> > 
> > It is RS-232, not USB.
> > 
> 
> RS-232 specifies a 50 foot maximum!
> 
> IF you use top quality cable, take care that your cable runs avoid the 
> fluorescent lighting fixtures, etc, you can use a great deal more than 
> that.  I've used more than 100 feet on occasion.  If it doesn't work, 
> you will get no sympathy.
> 
> I'd suggest that you put the computer on the top floor somewhere and use 
> Cat-5 cable for your RS232.

I was thinking I'd try the rather crude but elegant solution here: 
Using a Garmin GPS 18 LVC as NTP stratum-0 on Linux 2.6
http://time.qnan.org/




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