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Re: Accuracy of tracking programs



At 23:31 07/06/01 +0100, I wrote:


><snip>



>I have 2 computers in my shack,that are networked. Both are mid to high 
>range pentiums.
>On my main PC, ( this one ) I run LogSat 5.2 on my other PC I run Nova. I 
>have two programs,
>because each is better at one or another thing.
>
>LogSat is great for forward predictions,and is prettier, but I never did 
>get it to drive my KCT card.
>Nova is not so good at forward predictions, not so easy to use, but drives 
>the KCT great.
>
>Now here is the point, Nova consistently puts LEO satellites about 1 
>minute in front of LogSat,
>this makes no real difference to the high orbit satellites, but *is* 
>significant on LEO's

<snip>


  I tried again today, with the new keps as supplied by Amsat, the results 
are different from last night. Now the calculations by both programs give 
identical results to within 0.1 degrees and seconds in time . As an 
experiment I put last weeks keps back in and got the same around 1 minute 
error that I got last night. This seems to complicate matters as it seems 
that the results are KEP dependant. I wonder if one of the programs 
truncate or round off some of the decimal places on the elements, thus 
giving a variation dependant upon how precise the element set is?

I seem to have cried ' wolf ' a little prematurely, but at least it has 
generated some awareness that just cos' the PC says so, it can vary as to 
what is really happening. It was probably academic anyhow, as even with the 
errors of a few degrees, it's still well within most practical antenna beam 
widths, unless of course it's you that's got that 40' dish.....


____________________________

      G4DMF  QTHR   IO93HA
      Amsat-UK Member 5372
          g4dmf@amsat.org
      http://www.g4dmf.co.uk
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