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Homework Help: Radio Astronomy - power received

  1. Mar 13, 2007 #1
    1. The problem statement, all variables and given/known data
    Compare this to the power received on the ground from a geostationary satellite with a 1 W transmitter and with a transmission footprint of 1000 square km across (assume uniform power in footprint).


    3. The attempt at a solution
    I don't know where to start on this one pretty much. I mean I know that it is transmitting 1 W of power and that the intersection of this beam with the Earth's surface is 1000 square km, but I just don't know how I would go about determining the total power collected. There must be something that I'm missing because from the amount of marks allocated for this question you wouldn't receive 1 W of power. Any hints on what to do would be greatly appreciated.

    Cheers
     
  2. jcsd
  3. Mar 13, 2007 #2

    Dick

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    Compare WHAT with the power recieved from a 1W transmitter? I think you truncated the question.
     
  4. Mar 13, 2007 #3
    Yeah I did truncate the question, but it's not the comparing part that I'm concerned with. I'm just wanting to get a push in the right direction as to how I would calculate the power received by the satellite.

    But maybe the first part really does have something to do with it. The first part was this:

    Estimate the total energy collected by a radio telescope since 1950 assuming that the sky emits a uniform flux density of 1 Jy.

    So for that part I had to assume the area of the telescope and assume the bandwidth that was used too.
     
  5. Mar 14, 2007 #4

    Dick

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    Then I think you want to compare that with the energy it would receive from said satellite. The question as stated doesn't give, or give you a way to guess the area of the antenna.
     
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