Mark is correct. You want the amplifier as close to the original signal as possible, that way you aren't amplifying any noise and signal degradation.
That's not strictly true. If you put the amplifier too close to the source (LNB) then there is a danger you'll overload the amp's input thereby resulting in a distorted output.
I posted some pictures of my setup at home
here. That system distributes OTA DVB-T (Freeview) and satellite all over the house and can scale to 100's of rooms if needs be by cascading.