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

John Ackermann N8UR jra at febo.com
Sat Mar 28 01:34:19 UTC 2009

Poul-Henning is doing some really neat stuff with a software defined 
LORAN receiver, but he's not actually using that one for timekeeping 
(that I know of).  I didn't know he also had your design running as well.


David Mills said the following on 03/27/2009 08:24 PM:
> Johm,
> 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.
> Dave
> 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
> _______________________________________________
> questions mailing list
> questions at lists.ntp.org
> https://lists.ntp.org/mailman/listinfo/questions

More information about the questions mailing list