Re: Toggling time sync between two servers

vwvr6vw wrote:

Thanks. In this application, a few thousand dollars is not going to be
an issue. Having the correct time is critical and that is why I'm
hoping that managment will go for it. I believe the two sources we
have now are from GPS.
<snip>

Can you locate an antenna where it will have an unobstructed view of the entire sky? If so, you can buy a GPS receiver (GARMIN GPL18LVC) for less than $100 and connect it to a serial port on a computer running ntpd with support for refclocks and presto! It's a bit on the do it yourself side of things but it will get the job done. You'll need a soldering iron, a DB9 connector, and a five volt power supply.

Moving upscale a bit, you can get a Motorola Oncore M12M timing receiver (actually somebody else makes them now) from Synergy Systems. You get the one with the evaluation board. It's still pretty crude; a bare circuit board, but a power supply, antenna, and RS232 cable come with it. That will cost you $200. Plug it in, connect it to a serial port, install ntpd, configure it, and go.

Moving pretty far upscale, you can get a box from Symmetricom with a built in GPS receiver and NTP server. Plug it in to the AC outlet and your Ethernet. I think these go for something like $2500 and up. That's about $2300 above my budget for toys so I don't have one and won't unless someone gives me one for Christmas. I think that box may also come with an OCXO disciplined by the GPS to give some "holdover" capability if you lose signal from the satellites.

You can also get a box that gets the time from a CDMA Cell Phone base station (derived from GPS). You plug that box into AC, your network and a whip antenna. It, too, has a built-in NTP server.

You might want to get a couple of each.
.

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