[time-nuts] PC time app

David J Taylor david-taylor at blueyonder.co.uk
Sat Nov 26 07:40:03 UTC 2011


From: "Hal Murray" <>
Sent: Saturday, November 26, 2011 6:58 AM
To: "Discussion of precise time and frequency measurement" 
<time-nuts at febo.com>
Subject: Re: [time-nuts] PC time app

>
> david-taylor said:
>> Yes, although from some GPS devices the jitter may be worse than from
>> Internet servers (depending on your connection).
>
> I've been looking for "good", low cost GPS gizmos, preferably with no
> soldering required.  If anybody finds one, please let me/us know.
>
> The best I've found is the Garmin GPS-18x.  It is only "good" if you can 
> use
> the PPS signal and it requires some soldering.
>
> All the low cost GPS unit's I've tested have horrible jitter.  They are
> crappy without PPS support.
[]

I do agree with Hal's comments.  The one other unit I've found is this 
one, which I know I've mentioned here before:

  http://www.satsignal.eu/ntp/Sure-GPS.htm

but again some assembly is required, including soldering.  It can take its 
power from a spare USB port.

I did test the GPS 18(x) with a USB to serial adapter, and the PPS/DCD 
line was passed through, allowing NTP to work rather better than pure LAN 
sync, but not as good as a direct connection to the serial port DCD line. 
Not all USB/serial adapters and their drivers work as well.

Cheers,
David
-- 
SatSignal software - quality software written to your requirements
Web:  http://www.satsignal.eu
Email:  david-taylor at blueyonder.co.uk 




More information about the time-nuts mailing list