Installation guide

Overview 5
Satellite Communication Basics
All comm_'cations services, from ship-to-shore communications, radio and television
to communications satellites are assigned unique bands of frequencies within the
electromagnetic spectrum in which to operate.
Overview
To receive signals from the earth successfully and relay them back again, satellites use
very high frequency radio waves operating in the microwave frequency bands--either
the C-band or KU-hand. C-band satellites generally transmit in the frequency band of
3.7 to 4.2 Gigahertz (GHz), in what is known as the Fixed Satellite Service band or FSS.
However, these are the same frequencies occupied by ground-based point-to-point
communications, making C-band satellite reception more prone to interference.
KU-band satellites may be classified into two groups: low and medium power KU-band
satellites, transmitt'mg signals in the 11.7 to 12.2 GHz FSS band; and the new high-
power KU-band satellites transmiting in the 12.2 GHz to 12.7 GHz Direct Broadcast
Satellite service (DBS) band.
Unlike C-band satellites, these newer KU-band DBS satellites have exclusive rights to
the frequencies they occupy, and therefore have no microwave interference problems.
The RCA D SS System will receive programming from high-power KU-band satellites
operating in the DBS band.
Although C-band satellites are spaced 2° apart,high power KU-band satellites are
spaced 9° apart,and transmit at 120 ormore watts of power.
Because o f their lower frequency and transmitting power capabilities, C-band sate llites
require a large receiving dish, anywhere from 6 to 10 feet in diameter. The higher power
of KU-band satellites enables them to broadcast to a compact 18 inch diameter dish.
Satellite System
A satellite systemis made up of three basic dements:
• An uplink facility, which beams programming signals to satellites orbiting over the
equator.
• A satellite that receives the signals and re-transmits them hack to earth.
• A receiving station including the satellite dish.
The picture and sound information originating from astudio or broadcastfacility is first
sent to an uplink site, where it is processed and combined with other signals for
transmission on microwave frequencies. Next, a large uplink dish concentrates these
outgoing mierowave signals and beams them up to a satellite located 22,247 miles
above the equator. The satellite's receiving anteuna captures the incoming signals and
sends them to a receiver for further processing. These signals, which contain the
original picture and sound information, are converted to another group of microwave
frequencies, then sent to an amplifier for transmission back to earth. This whole
receiver/transmitter package is called a transponder. The outgoing signals from the
transponder are then reflected off a transmitting antenna, which focuses the micro-