That depends on a few things. Which dish system, which LNB, switch mounted at the dish or at the house....
I have a dual-dual LNB on mine, so that's 4 wires that come out of the dish. Within 4 feet of the dish, I have 2 switches to combine 1 wire from each LNB, so 4 wires to 2. Those 2 come into the house and go in different directions, each to a separate receiver.
The newer dishes don't have all that.
http://www.dishnetwork.com/download...als/installation/SHOW_949_dishpro_install.pdf
Edit: My neighbor got HD recently, and he now has 2 dishes, each in a different place pointed in a different angle. Wires run in from both to a switch to combine them.