"Dave Hart" <[email protected]> wrote in message
news:CAMbSiYBLnxaj_x4vch3eNDqwUDX+d5sGcHyr8zBe3Jh0C2K=y...@mail.gmail.com...
On Thu, May 24, 2012 at 4:24 PM, Chris Albertson
<[email protected]> wrote:
Lots of good discussion here but I found an easy way to stay "on-time"
while the Internet is down and GPS is not available. There are some
people on eBay selling Rubinium oscillators for about $40. They have
a pulse per second output. These Rb clocks will keep NTP within
reasonable specs for a LONG time. It does required some effort to set
up. Just wanted to point out one more option.
ntpd requires reference clocks provide time, not just frequency. How
do you discipline the Rb PPS to occur at the top of the UTC second (or
a fixed offset from the top)?
Cheers,
Dave Hart
Agreed, Dave. The way I read the message was for /temporary/ coverage,
not a fully disconnected solution. For US $40 (or somewhat more) you
could easily get a secondary GPS reference such as:
Trimble Resolution SMT Timing GPS OEM board
eBay 290696970497 (price has gone up, though)
Sure Electronics GPS evaluation board
http://www.sureelectronics.net/goods.php?id=99
http://www.satsignal.eu/ntp/Sure-GPS.htm
Garmin GPS 18x LVC
http://www.satsignal.eu/ntp/FreeBSD-GPS-PPS.htm
http://www.satsignal.eu/ntp/NTP-on-Windows-serial-port.html
and use these to provide backup servers to cover the outage.
Cheers,
David
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