[amsat-bb] Re: Pass predictions and differences in software

Alexandru Csete alexc at phys.au.dk
Mon Jul 13 12:27:15 PDT 2009

Hi LeRoy,

Which version of gpredict are you using? The one that is included with
Ubuntu? That version is very much out of date and did have several bugs
that could affect pass predictions. In particular the "time controller"
function was very immature back then.

Did you try the predict pass functions instead of advancing the clock
(i.e. right click on a satellite)? 


On Mon, 13 Jul 2009 18:27:42 +0000
kd8bxp at aol.com wrote:

> Good afternoon
> I am running gpredict on an ubuntu linux box - I am looking at the
> SO50 satellite -
> It is currently 1412 (1812utc) - I advanced the clock of the software
> forward by about 3 hrs (1712 local) and see what looks like a great
> pass on screen
> I went to verify using the webbased prediction on the amsat website,
> and. Don't see anything in the list of passes even close to what
> gpredict says will happen in the future
> I updated the keps thinking maybe they were out day, and got the same
> results
> I then fired up my winXP machine and SatPC32 - and got results that
> are closer to what the amsat site says. 
> When looking at real time, all three show the SO50 in just about the
> same spot
> I think I believe the amsat site and satPC32 software. 
> Not sure of the question to this post - wondering more or less what
> factors effect how the pass predictions work. When they (or at least
> the two I have control over) have updated keps shouldn't they give
> the same information or realitivly close - as I look at the two
> programs running side by side I do see slight differences in where
> SO50 is located on the map currently.  But it is only slight and may
> have more to do with the scale of the display maps and not the
> software.  
> If I advance the time thou I don't get the same results. And this
> confuses me
> Thanks,
> LeRoy, KD8BXP
> http://www.HamOhio.com
> Sent on the Now Network™ from my Sprint® BlackBerry

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