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Signal Transmission from Mars to Earth

  1. May 5, 2007 #1
    When they say it takes about 5-6 mins to send radio signal back to earth, what kind radio signal are they talking about? Not FM/AM signal right?
     
  2. jcsd
  3. May 6, 2007 #2
    I'm betting digital FM
     
  4. May 6, 2007 #3

    russ_watters

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    Staff: Mentor

    Looks like the frequency is in the UHF range (the same frequency band as some tv stations and many other types of radio communications), and yes, I'd also guess that they are digital, frequency modulated.

    Also, at its minimum, Mars is about 35 million miles (3 minutes) and at its maximum, it is about 220 million miles (19 minutes).
     
    Last edited: May 6, 2007
  5. May 7, 2007 #4
    NASA uses microwave C band and X band frequencies to communicate with the probes. Uplink is in C band about in 7.8 GHz range, and downlink is 8.4 GHz.

    Microwaves travel alot better in space, require less power, and more data can be sent than on lower frequency bands.

    I don't remember what modulation Nasa uses, but it's probably QAM because you can cram alot of data.

    If interested, you can build your own receiver to pick up signal from Mars probes, no kidding.

    http://www.uhf-satcom.com/vex/

    hope that helps
     
  6. May 8, 2007 #5
    Wow cool contraptions. Thanks. I'm try to set one up.
     
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