Why Satellite?

An Introduction to the Technology and Services

There are more than 1000 operational satellites in varying orbits around the earth, including satellites used for:

  • Communications & Broadcasting
  • Military & Reconnaissance
  • Meteorology
  • Navigation
  • Imaging & Remote Sensing
  • Research

Communications & broadcasting satellites typically orbit above the equator at about 35,800 kilometers (22,300 miles) in what is called the “geostationary arc.” From this arc, the satellite appears to remain in a fixed location above the earth – a highly desirable feature that enables antennas on the ground to point to (or access) the satellite without tracking its movement, and then receive or transmit communications signals.

Because geostationary (GEO) satellites operate at a very high altitude above the equator, a single satellite can cover, or see, approximately one-third of the earth’s surface. This makes GEO communications satellites extremely powerful for broadcasting content such as TV programs. One GEO satellite can cover continents (e.g., North & South America), and three can fully cover the earth (except for the extreme northern and southern latitudes).

GEO satellites are often described by their longitudinal orbital location, or “slot”, such as Telesat’s Anik F1 at 107.3 degrees West longitude. The orbital slot designations of “East” and “West” are in relation to the Prime Meridian that passes through Greenwich, London, United Kingdom.

There are more than 200 GEO communications and broadcasting satellites in orbit today around the world. Main frequencies are:

C-band –First band to be used in the commercial satcom industry

  • Uses 3.7 to 4.2 GHz frequency band for transmissions from the satellite to the receive earth terminal
  • Consistent frequency allocation worldwide with low-cost and well-proven earth station equipment
  • Supports video broadcasting (cable and over-the-air), and telecom trunking
  • Minimally affected by atmospheric conditions
  • Telesat was the first to use C-band in a domestic GEO communications satellite

Ku-band – Growth began in the 1980s

  • Uses frequency sub-bands in the range 10.95-11.2; 11.45-11.7; 11.7-12.2; and 12.25-12.75 GHz frequency band for transmissions from the satellite to the receive terminal and allows for smaller dishes
  • Supports satellite Direct-to-Home (DTH) and VSAT networking
  • Still growing rapidly in most world regions; mature in North America and Europe
  • Some atmospheric effects, particularly in tropical regions
  • Telesat was the first in the world to commercialize Ku-band on the Anik B satellite

Ka-band – Growth began in the 2000s

  • Uses frequency sub-bands in the range 17.7GHz to 21.2 GHz for transmissions from the satellite to the receive terminal
  • Ka frequencies have the shortest wavelength of the three commercial fixed satellite bands and are most affected by atmospheric absorption
  • Short wavelengths allow for multiple spot beams each of which concentrates the satellite power into a small geographic area
  • Spot beam Ka-band satellites are well suited for two-way broadband services such as high speed Internet access for homes and small businesses
  • Major consumer broadband services using advanced Ka-band satellites are underway in both North America and Europe
  • Ka-band spot beams can also support distribution of regional or local broadcast programming and interactive television services
  • Telesat was the first in the world to successfully commercialize consumer Ka-band broadband services using the Anik F2 satellite