[time-nuts] common mode loran comparisons

Brooke Clarke brooke at pacific.net
Sat Jun 2 16:39:38 EDT 2007


Hi Tom:

NIST was monitoring 9940 not that long ago and I called them to ask about the 
very poor numbers.  They said the monitoring was being done with an antenna in 
Colorado!  So you're not missing much in that regard.

I'm almost in the shadow of the Middletown station.  A few months ago they were 
testing the new Data Channel, but are not now.  I've been thinking of making up 
a PCB board for the Burhans LORAN-C receiver that was published some years ago 
in a series of articles about LORAN-C.  It was small and has outputs that work 
with micro controllers.  But the R.F. front end in the Austron 2100 receivers 
is far and away a much better way to go.  They have variable gain and filtering.

Once the modernization program is complete the timing will change from the 
current Master -> delay -> slave to one based on UTC.  That will enable "all in 
view" LOARN-C receivers.

Have Fun,

Brooke Clarke
http://www.PRC68.com
http://www.precisionclock.com



tom jones wrote:
> I'm getting great results monitoring daily phase changes of the fallon loran master station.
>   I don't have any computer logging from my austron 2100's but manual readings taken several times a day show 10 to 30 nanosec of phase change throughout the day and about 0 to 10 ns day to day and about 0 to 30ns week to week.
>    
>   I have an hp-5061 providing reference for two seperate 2100's one f model the other is the timing type.both austrons readings agree with each other.
>   I also have sirf type 1pps gps receiver that agrees with the long term phase changes of all the above.
>    
>   The reading are good enough to participate in common mode measurements with fellow time-nuts that have cesium and austron 2100 loran monitors.
>    
>   I'm using a funaro 80 marine loran as an antenna pre-amp for the 2100's coupled by capacitors.to the austron.  Any old loran that has two wire antenna coupler could be used as a preamp for the austron 2100.
>     The austron 2100 does not provide power for said coupler so you should use matching receiver thats belongs with antenna coupler.
>    
>   My antenna is indoor and works fairly well without preamp but works better with furano loran preamp.  I've never owned the orignal antenna designed for the austorn 2100 but assume it works well.
>    
>   My recent data;
>   Time  loran1  loran2 gps  date      doy
>   12:24 -013     -025   772  5-27-07 147
> 15:00 -011     -024   784  5-27-07 147       
> 06:13 -014     -026   759  5-28-07 148
> 09:43 -014     -026   771  5-28-07 148
> 14;07 -010     -023   799  5-28-07 148
>   20:11 -009     -022   807  
>   05:28 -013     -025   775  5-29-07 149             
> 10:25 -014     -028   743 
> 18:06 -016     -029   739 
> 21:40 -013     -026   760 
>   05:27 -015     -028   745  5-30-07 150
>   06:14 -016     -028   754  5-31-07 151
>   07:25 -018     -031   722  6-01-07 152
>   07:13 -014     -027   777  6-02-07 153
>        
> I would enjoy comparing this measured loran data with someone elses.
>    
>   Nist & unso aren't monitoring chain 9940 so I need help from fellow time-nuts.
>    
>    
> 
>  
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