[ntp:questions] NMEA ref.clock better than my ISP's timeserver?

David Lord snews at lordynet.org
Thu Jun 11 08:11:50 UTC 2009

David J Taylor wrote:
> David Lord wrote:
> []
>> I eventually ordered from gpsw.co.uk, UKP 71.02 inclusive. I'd
>> searched their site prior to trying the US ones and not been able to
>> locate the GPS 18x-LVC and only went back after it being confirmed
>> here they stocked the product.
> I also ordered from  GPS warehouse and it arrived very quickly.
>  http://www.gpsw.co.uk/details/prod2402.html
>> I've not yet connected the GPS 18x as still thinking about where to
>> mount it. I previously tried with a BR304 without pps and had 80%
>> of time +/- 25ms, much worse than for time from internet whilst a
>> Conrad DCF module used over a few days gave 80% at +/- 2ms, better
>> than expected, but both BR304 and DCF have reception difficulties.
>> David
> Mine is now sitting indoors, near the roof of an upstairs room.  It's a 
> lot more sensitive than the plain "18" model, so I'm trying it indoors 
> rather than on the roof  (where my 18 lives).  It's a backup, and 
> working into a rather poor Windows box, but keeping generally within 0.5ms.
>  http://www.satsignal.eu/mrtg/stamsund_ntp_2.html
> I couldn't see any change between the outdoors 18 and the indoors 18x on 
> that PC.  The changeover was on Friday, May 22, week 21 - spot any 
> difference?

Late last night I got round to connecting the Garmin GPS18x-LVC and
just after midnight it stepped from around 60s to 0.5ms and 8 hours
later is between -74us and +62us. The module is in south facing
upstairs window in same location I failed to get anything useful
from the Globalsat BR304. Now I need to make a 30m extender cable to
get the signals downstairs to back of house to connect to servers.


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