All satellites have what is called a "footprint" and the further you get away from the center of the footprint or beam, the weaker the signals are going to be, and the larger the dish you will need in order to receive a clear picture. Once you get past the line of sight view to a satellite the signal is completely lost and no size of dish will be large enough to capture enough signal in order to get a usable picture and/or sound from that satellite. This works much like the beam of light coming from a flashlight in a dark area.
The maps below show which regions are covered by a specific satellite beam and it will also indicate which type of satellite antenna you will need which is large enough to receive the signal. For a larger view click on the image.