[ntp:questions] Re: Garmin GPS18USB and NTP on Win2k

Richard B. Gilbert rgilbert88 at comcast.net
Sat Jun 25 22:32:00 UTC 2005

ecoca at eed.usv.ro wrote:

>I have a Garmin GPS18USB on a win2k server machine (driver #20). I've
>installed NTP 4.2.0a distribution. My question is about the jitter - I
>notice a big value of the jitter (30 to 80), sometimes the offset being
>too much - above 200-300 ms for shot periods (one or two request
>intervals). Is there anyone having the same experience ?
>Thank you !
I have not tried it myself but I have read reports the the USB interface 
is ill suited to timing applications; that the latency is high enough to 
produce large values of jitter and offsets.

USB does work well for navigation but I would not use it for timing.

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