[ntp:questions] Stick to PPS, even if the prefer server fails

David Mills mills at udel.edu
Sat Mar 28 00:24:21 UTC 2009


Don't get me going on the Austron 21--. I had one and a 2200, too, and 
they cost me more in repeated repari bills than new Spectracom GP 
receivers, so I junked them. As for the Coasties, they have threatened 
to turn LORSTAs off every few years since 1990. As for your suspicion 
that you are the only NTP server synchronized to LORAN-C, be advised 
Poul-Henning Kamp has a clone of my receiver running in Denmark with a 
Rubidium timebase. Apparently, LORAN-C has new life in Europe.


DaveJohn Ackermann N8UR wrote:

> David Mills said the following on 03/27/2009 05:44 PM:
>> To John: I suspect you know that all LORSTA stations run by the Coast 
>> Guard include in the weekly announcement series a time-of-coincidence 
>> (TOC) second at which the epoch of the second is equal to the epoch 
>> of the GRI. My Astron LORAN-C receiver, which was modified by the 
>> Coast Guard, flashes a light at the TOC. The TOCs and the intervals 
>> between them vary up to several minutes depending on the GRI of the 
>> chain. I made provisions for the TOC in the LORAN-C receiver I built 
>> some years ago, but never completed the code to exploit them.
> Hi Dave --
> Yes, the TOC can be used to generate an on-time PPS.  The Austron 2100 
> (sometimes referred to as the "T" model) receiver has that capability 
> (the more common 2100F version does not; it is useful only for 
> frequency comparisons).
> I drive one of my NTP servers (a modified Soekris SBC running nanoBSD) 
> tied to the Austron 2100, and its crystal oscillator is locked to an 
> Austron 2010B disciplined oscillator that is driven from the LORAN 
> receiver.  I suspect that this may be the only LORAN-based NTP system 
> running anywhere today.  It keeps very good time; in fact, its noise 
> is comparable to a similar Soekris box that gets its PPS and 
> oscillator from a Z3801A GPSDO.
> Of course, the Coast Guard just announced that they plan to turn the 
> US LORSTAs off in 2010 as part of budget cuts.  I don't know if that 
> is political maneuvering to get a bigger piece of the pie, or a done 
> deal.
> John

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