[time-nuts] Loran - any good for timekeeping?

[Brooke Clarke]

Hi John:

Setting the 2100T is really a two step process.  After  you have done 
all the setup possible and then connect you house 1 PPS and put in a 
phony TOC that's say 10 seconds ahead, then at the TOC the 2100T will 
sync it's 1 PPS output (you will get a red error light).  You need to do 
this to get the seconds ticking with UTC.  Then you can set the time so 
it ticks over on the UTC second edge.  Then do a real TOC sync.
More at:
http://www.pacificsites.com/~brooke/A2100F.shtml#2100T

Have Fun,

Brooke

John Ackermann N8UR wrote:

>M. Warner Losh wrote:
>
>  
>
>>Can't you recover the time by tracking multiple chains and using the
>>relationship between them to come up with at least small number of
>>possible seconds?  Hasn't the US started broadcasting data that can be
>>used to know which second you are at?
>>    
>>
>
>I don't think that the US has started broadcasting a timecode, though I 
>think those plans are in the works.
>
>I have to look at the Austron 2100T manual to get the exact sequence of 
>events, but basically you set the clock, feed an external PPS signal 
>that is roughly accurate (within some tens of milliseconds, I think), 
>and then enter the next time of coincidence (TOC) which you obtain from 
>the USNO (http://tycho.usno.navy.mil/lortoc.html).  The TOC is when the 
>Loran pulse coincides with the UTC second.  When the TOC rolls around 
>(which occurs a couple of times per day, the receiver locks to that and 
>you can remove the external PPS.  From that point on, the PPS output 
>should track with the stability of the Loran signal unless/until it 
>loses lock.
>
>Not sure about the idea of tracking multiple chains; it seems like that 
>should work, but that's not how the Austron receiver, at least, does it.
>
>John
>
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