[ntp:questions] Re: Looking for time sync hardware supported under Linux for under $400?

Richard B. Gilbert rgilbert88 at comcast.net
Tue Jan 17 20:41:07 UTC 2006


Mark Hansen wrote:

> It is possible to find a time synchronization device which is
> supported by the NTP software (NTP version 4.2.0.a on CentOS 4.2)
> for under $400?
>
> In looking at the various solutions, all I see one units which
> appear to be pretty expensive. Are there less-expensive (perhaps
> GPS-based) units which are supported by NTP?
>
> For example, I found the InSync GPS Master Clock, shown here:
>
>   
> <http://www.bytefusion.com/products/ntm/master_clock/gps_master_clock.htm> 
>
>
> but it appears to want to use its own Windows-based driver, and I
> don't see it mentioned in the 'Comprehensive list of clock drivers'
> which is included in the documentation for the NTP server.
>
> Is there anything available in the few-hundred-dollar price range?
>
> Thanks,

You can get an "FS Oncore" GPS Timing receiver from Synergy Systems 
<http://www.synergy-gps.com/>

You should plan to purchase one with the "evaluation kit" unless you are 
equipped to design and produce your own circuit board.  I bought one 
about fourteen months ago when they were still manufactured by Motorola 
and paid about $200 US for it.   It comes with a power supply (wall 
wart) and an antenna.  I've been using it with a Sun Ultra 10 running 
Solaris 8.   It generally synchronizes within a millisecond or less.
sunblok_$ ntpq -p
     remote           refid      st t when poll reach   delay   offset  
jitter
==============================================================================
*GPS_ONCORE(0)   .GPS.            0 l    4   16  377    0.000    0.001   
0.001

There are other GPS receivers that will work quite nicely; one sells for 
around $85 US.   Be certain to get one with a serial (RS-232) interface 
(the USB interface does not work well in timing applications).  Also be 
certain to get a receiver designed for timing applications.  Many GPS 
receivers are designed for navigation and it is generally not possible 
for a receiver to do both timing and navigation well.




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