[ntp:questions] NTP server with no network, no GPS signal

Chris Albertson albertson.chris at gmail.com
Fri Apr 29 15:17:45 UTC 2011

On Fri, Apr 29, 2011 at 4:10 AM, Cristian Seres <cristian-2 at contrasec.fi> wrote:
> Hi!
> I am looking for a solution to install an NTP server in a very restricted
> network which can not be connected to other networks even through a firewall
> because of strict security policy. RS232 and usb are ok. Using GPS or DCF77
> reference clocks would require a long antenna wire to get signal. Installing
> the antenna cable would be expensive, but there is good LAN cabling between
> a space with good GPS signal and the room with high security.

This is easy.  Install the GPS but use a very short antenna cable.
Then the output of a GPS is in two parts (1) A serial data stream and
(2) a pulse per second.   Both of these can go over the LAN cable.

You never want a long antenna cable because of the losses in a long
run.  It is best to keep that cable short and send the data from the
PS back over a digital cable
Chris Albertson
Redondo Beach, California

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