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Because Dish Network has been around so long, they've
sort of boxed themselves into a corner when it comes to signal
distribution. All of their programming could be carried on one satellite,
received with a single bandstacked LNB, and distributed with a
splitter, but they've gone in a lot of completely different directions
and have to support a diverse array of orbital locations, switches and
receivers. Some of the switches are kind of complicated and require
other accessories to function properly. Here's how they work.
A diplexer takes an L band satellite IF signal (950-2150
MHz) and combines it with a VHF/UHF over the air or cable TV signal
MHz), or vice versa. A pair of diplexers, placed at the ends of the
cable allows both signals to be combined onto a single cable and
separated at their destination. These have been around a while, to let
people combine signals from an off-air antenna with their satellite
feed, but Dish Network uses them for "backfeeding".
A dual tuner receiver like the 322 or 222
uses a UHF output (25 MHz to 900 MHz) to distribute programming to a
second TV. To save on a cable, that signal can be combined with the
incoming satellite IF signal and separated at the point where all of
the home's cabling comes together to be sent on to its destination TV.
In a Dish Pro Plus
system a dual tuner receiver is fed with a single cable, rather than
the two that would be needed for Dish
Pro or Legacy. The
way that this works is that the switch sends the signal for one tuner
on the low band, 950-1450 MHz, and the second tuner's signal on the
higher band, 1650-2150 MHz. The separator is simply a filter that
accepts both bands, and outputs 950-1450 to tuner one and the 1650-2150
to tuner two. It also allows power and DiSEqC signals to the switch
from tuner one only.
A triplexer is simply a separator and diplexer combined
into one device. It's more or less a labor saving thing, since
technicians used to have to install a diplexer and a separator.
Splitters aren't normally used for satellite IF
distribution, except in a few rare cases. A splitter may be use to
connect a single bandstacked LNB
to multiple receivers or switches, or to connect a single polarity of a
to multiple receivers or switches. Splitters are frequently used in new Dish
Network installations, however, to route UHF signals from a dual tuner
receiver to multiple receivers, and to connect multiple Joey receivers
in a Hopper/Joey system.
A tap is a new addition to the Dish Network lineup. It
functions almost the same as a diplexer, except that the input and output pass both UHF and satellite IF, while a
third port passes only UHF. It's used in the line between the dpX node
and the Hopper to connect Joeys or a Hopper Internet Connector.