This article is from the Digital Broadcast Satellites FAQ, by Brian Trosko firstname.lastname@example.org with numerous contributions by others.
Without additional parts, two. With the appropriate
additional parts, at least 30.
To hook up more than two receivers involves a part called
a voltage switch. You will need one voltage switch for
each receiver you want to hook up. The outputs coming off
of the dish get split, and each voltage switch gets fed signal
from both outputs. Then the output from the voltage switch gets
fed to the satellite receiver.
There are also parts called multiswitches that take feeds from
both LNBs on the dish and distribute them to multiple receivers.
In essence, a multiswitch is several voltage switches combined
in one unit. Sony makes a multiswitch suitable for use with
up to four receivers. It retails for around one hundred dollars.
Multiswitches for many receivers, even 16 or 32, are available
from companies like ChannelMaster, but are much more expensive.