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Size of Satellite TV Dish -v- Radio

  1. Feb 13, 2010 #1
    Hi there... I have a question regarding satellite. If I am posting in the wrong place, I'm very sorry (in advance :blushing:) Here's my question. Why is a satellite dish for TV (think Dish Network) so much bigger than one for satellite radio?

    Sure would be more attractive to have a teeny unit on top of a home than the big dish. I found this thread https://www.physicsforums.com/archive/index.php/t-125286.html but it didn't really answer the question.
  2. jcsd
  3. Feb 13, 2010 #2


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    Simply signal strength. It's just like big binoculars collect more light than small binoculars.
    Radio sends less data than TV so you can don't need to grab as much data/sec so you can use a weaker signal (and more error correction) assuming the same broadcast power
  4. Feb 13, 2010 #3
    Thank you, thank you. The analogy of the binoculars helped a lot (I actually thought radio sent more data not less). Many thanks to you!
  5. Feb 13, 2010 #4


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    If you think Dish or DirecTV antennas are big, you must never have used or lived next to someone who used a Big Ugly Dish (BUD). :biggrin:
  6. Feb 13, 2010 #5
    Wow! No doubt... can you imagine? :eek:
  7. Feb 13, 2010 #6


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    There is also the factor of bandwidth and the required signal to noise ratio. If your TV requires a bandwidth of something like 27MHz then the receiver will let in a lot more noise than a narrow band channel for radio.
    This is an over simplification because I'm comparing the performance of the 'old' analogue FM broadcast TV system, used in Satellite TV with the modern digital radio systems, but the message is basically that if you want to receive wide bandwidth signals, you need a wider RF bandwidth for your receiver which will let in more noise as well, which leads to the requirement for more powerful transmitter or a bigger receiving dish.
    Modern digital signals have changed the limits but the same basic principal will always apply.
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