[LinuxPPS] Ultimate time server

[Hal V. Engel]

On Tuesday, December 28, 2010 05:54:13 am Udo van den Heuvel wrote:
> On 2010-12-28 14:24, Paul Lavender wrote:
> > board crystal. Has anybody replaced the crystal with a higher stability
> > device, such as a temperature compensated crystal, or even better
> > something derived from the Rubidium maser?
> 
> I have seen a thermostat built by one of the readers:
> 
> http://rembl.org/index.php/2008/12/31/thermostat-for-system-clock/
> 
> Will you also implement a PTP server?
> 
> Udo

There is also a crystal temperature control device intended for amateur radio 
use for UHF and microwave work (moon bounce and the like) from a German 
company.  You basically shrink wrap it to your crystal and give it power.  I 
think it needed 8 to 14 volts.  So you should be able to power it from a 12 
volt supply line from the computer PSU.   It is designed to keep the crystal 
at about 42C +-1C.  When I checked into it a while back it was priced at about 
$18 so it was not expensive.

There is also a web page out there about someone using a GPS disciplined 
frequency source and a frequency divider to drive the motherboard.  He was 
using a BSD machine and was able to get very accurate results.  Here is a link

http://www.febo.com/pages/soekris/ 

This type of thing does require a motherboard modification so it is not for the 
faint of heart or those with bad eyes or unsteady hands. 

A more stable freq. source for the motherboard will help things a lot.  At 
that point the limiting factor in how accurate your ntp server becomes is 
latency in the serial interrupt handler.

Hal