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Re: [MSG-1] Increased BER?

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  • geojohnt@aol.com
    In a message dated 29/11/05 15:43:11 GMT Standard Time, tdavid@dsl.pipex.com writes: I understood that the sat gives the impression that it moves in a fig 8
    Message 1 of 15 , Dec 1, 2005
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      In a message dated 29/11/05 15:43:11 GMT Standard Time, tdavid@...
      writes:

      I understood that the sat gives the impression that it moves in a fig 8
      during the 24 hrs. If one looked at a ground station com sat terminal the dish
      was always on the move and if plotted it moved through a fig 8. May be the
      small dish that we use is not big enough to capture the beam when it is just off
      centre.


      David,

      Indeed, geostationary satellites that develop inclination do follow the so
      called figure of eight pattern. I don't understand why they don't just move N -
      S in a straight line.

      Anyway, none of 'our' satellite demonstrate an inclination that we would be
      aware of except Meteosat-5 whose inclination must now be more than 8 deg.
      TV broadcast satellites [Astra 1 and 2, Hot Bird, etc.] are kept within very
      tight limits.
      Though they do of course move, they don't move out of the beam width of a
      properly aligned dish.

      Regards,
      John.


      [Non-text portions of this message have been removed]
    • Trevor David
      I agree with you but I think it is the earth that wobbles on it`s axis through out the day giving the impression that the sat is moving. ... From:
      Message 2 of 15 , Dec 1, 2005
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        I agree with you but I think it is the earth that "wobbles" on it`s axis through out the day giving the impression that the sat is moving.
        ----- Original Message -----
        From: geojohnt@...
        To: MSG-1@yahoogroups.com
        Sent: Thursday, December 01, 2005 11:34 AM
        Subject: Re: [MSG-1] Increased BER?



        In a message dated 29/11/05 15:43:11 GMT Standard Time, tdavid@...
        writes:

        I understood that the sat gives the impression that it moves in a fig 8
        during the 24 hrs. If one looked at a ground station com sat terminal the dish
        was always on the move and if plotted it moved through a fig 8. May be the
        small dish that we use is not big enough to capture the beam when it is just off
        centre.


        David,

        Indeed, geostationary satellites that develop inclination do follow the so
        called figure of eight pattern. I don't understand why they don't just move N -
        S in a straight line.

        Anyway, none of 'our' satellite demonstrate an inclination that we would be
        aware of except Meteosat-5 whose inclination must now be more than 8 deg.
        TV broadcast satellites [Astra 1 and 2, Hot Bird, etc.] are kept within very
        tight limits.
        Though they do of course move, they don't move out of the beam width of a
        properly aligned dish.

        Regards,
        John.


        [Non-text portions of this message have been removed]



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      • David J Taylor
        ... The satellite s inclination makes it move far more than any earth wobble! One thing which was wrongly stated earlier - having a smaller antenna should mean
        Message 3 of 15 , Dec 1, 2005
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          Trevor David wrote:
          > I agree with you but I think it is the earth that "wobbles" on it`s
          > axis through out the day giving the impression that the sat is
          > moving.

          The satellite's inclination makes it move far more than any earth wobble!

          One thing which was wrongly stated earlier - having a smaller antenna
          should mean that its beamwidth greater, and therefore less sensitive to
          any orbital wobble, although of course the margin for rain etc. will be
          less because of the weaker signal.

          Cheers,
          David
          --
          SatSignal Software - quality software written to your requirements
          Web: http://www.satsignal.net
          Email: davidtaylor@...
        • John Parkins
          Hello Trevor and all, There s quite a good description of this effect here: http://www.geocities.com/senol_gulgonul/uydu/ Thursday, December 1, 2005, 11:46:43
          Message 4 of 15 , Dec 1, 2005
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            Hello Trevor and all,

            There's quite a good description of this effect here:

            http://www.geocities.com/senol_gulgonul/uydu/

            Thursday, December 1, 2005, 11:46:43 AM, you wrote:

            TD> I agree with you but I think it is the earth that "wobbles" on
            TD> it`s axis through out the day giving the impression that the sat is moving.

            --
            Best regards,
            John mailto:kvp@...
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