Re: [SAGE] Cheap USB NTP Reference Clocks?

[Brad Knowles <brad@stop.mail-abuse.org>]

At 2:12 PM -0500 2006-01-03, John Stoffel wrote:

>  Anyone got a pointer to a cheap USB (or serial) NTP Reference clock?
>  Someone mentioned one recently on LOPSA and/or SAGE, but I can't seem
>  to find the reference anywhere...

	The best place to ask questions like this is the newsgroup 
comp.protocols.time.ntp, which is also gatewayed to the mailing list 
questions@ntp.isc.org.

	In short, I believe that the Garmin GPS 18LVC is widely 
considered in the community to be a decent inexpensive consumer-grade 
GPS device that also handles time reasonably accurately.  The 
previous hacker favourite used to be the Motorola Oncore 12+, but I 
believe that this product has been discontinued by Motorola and may 
have been sold to another company.

	If you're looking for something even less expensive, you can 
build a radio receiver for something like $40.  We try to keep the 
NTP Public Services Project page at <http://ntp.isc.org/> as 
up-to-date as we can.  From our external links page at 
<http://ntp.isc.org/bin/view/Main/ExternalTimeRelatedLinks>, you can 
find plans for building your own WWVB receiver at 
<http://www.febo.com/time-freq/wwvb/antenna/index.html> or a 
different take on the same concept at 
<http://www.buzzard.org.uk/jonathan/radioclock.html>.  You may also 
be interested in the NIST page of Time and Frequency Receivers at 
<http://tf.nist.gov/timefreq/general/receiverlist.htm>.

>  Needs to work with either Solaris or Linux servers.

	Solaris should be no problem.  We have high level people at Sun 
who hack on the kernel to adapt it to the needs of good timekeeping, 
and they also hack on the NTP code to bring in new Solaris features 
to help improve our existing timekeeping capabilities.

	Linux may take some work to get to work well, especially if it's 
a more recent version (based on the 2.6 kernel).  I'd encourage you 
to read the appropriate pages on the NTP Public Services Project as 
well as in the NTP FAQ.

-- 
Brad Knowles, <brad@stop.mail-abuse.org>

"Those who would give up essential Liberty, to purchase a little
temporary Safety, deserve neither Liberty nor Safety."

     -- Benjamin Franklin (1706-1790), reply of the Pennsylvania
     Assembly to the Governor, November 11, 1755

  LOPSA member since December 2005.  See <http://www.lopsa.org/>.