This article is from the Digital Broadcast Satellites FAQ, by Brian Trosko email@example.com with numerous contributions by others.
Ideally, the coaxial cable between the dish and the receiver
should be high-quality RG-6. High-quality RG-59 can work,
but only for short runs, and even then it knocks the signal
strength back substantially.
Several individuals have reported successful installations
using long runs of RG-59. If you've already run RG-59,
you have nothing to lose by trying it - it just might work.
But if you're running new cable specifically for the dish,
play it safe and use RG-6.
There is a coaxial RF output on the back of the satellite
receiver, intended for a run to a second television, or for
televisions without video inputs. RG-59 would be sufficient
for that output. This means that it is possible to run from
the RF output to your cable junction box and send the signal
from one satellite receiver throughout the house.