Disadvantages of Satellites

lThe disadvantages of satellite communication:
           High initial cost.
           Susceptible to noise and interference.
            Launching satellites into orbit is costly.

Satellite bandwidth is gradually becoming used up.

There is a larger propagation delay in satellite communication than in terrestrial communication.

Advantages of Satellites

lThe advantages of satellite communication over terrestrial communication are:

The coverage area of a satellite greatly exceeds that of a terrestrial system.

Transmission cost of a satellite is independent of the distance from the center of the coverage area.

Satellite to Satellite communication is very precise.


HIGH bandwidths are available to use.


They are very cheap for the long distance communications.

How do Satellites Work

Two Stations on Earth want to communicate through radio broadcast but are too far away to use conventional means.

Earth stations send information in the form of high powered, high frequency (GHz range) signals 

        to satellites which receive and retransmit the signals back to earth where they are received by other earth stations in the coverage area of the satellite. The area which receives a signal of useful strength from the satellite is known as the satellite's footprint. 

The transmission system from the earth station to the satellite is called the uplink, and the system from the satellite to the earth station is called the downlink.

The two stations can use a satellite as a relay station for their communication

One Earth Station sends a transmission to the satellite.  This is called a Uplink.

The satellite Transponder converts the signal and sends it down to the second earth station.  This is called a Downlink.

How Satellites are used

How Satellites are used:

Service Types

Fixed Service Satellites (FSS):
FSS systems handle communications for thousands of individual cell phones in a specific area. FSS systems are capable of handling cell phone calls, text messages, images, videos, and any other type of file that can be sent or received via standard GSM signals.

•Example:  Point to Point Communication

Broadcast Service Satellites (BSS):

•Example:  Satellite Television/Radio

•Also called Direct Broadcast Service (DBS).

Mobile Service Satellites (MSS)

•Example:  Satellite Phones

Geostationary Earth Orbit (GEO)

GEO - Geostationary Earth Orbit :

 These satellites are in orbit 35,863 km above the earth’s surface along the equator.

i.e., Geostationary or communications satellites are PARKED in space 22,300 miles (35,900 km) above the equator of the STATIONARY earth. 

Objects in Geostationary orbit revolve around the earth at the same speed as the earth rotates.  This means GEO satellites remain in the same position relative to the surface of earth.
Geostationary satellites are used for weather forecasting, satellite TV, satellite radio and most other types of global communications.

Low Earth Orbit (LEO)

LEO- Low Earth Orbit :

LEO satellites are much closer to the earth than GEO satellites, ranging from 500 to 1,500 km above the surface.

LEO satellites don’t stay in fixed position relative to the surface, and are only visible for 15 to 20 minutes each pass.

A network of LEO satellites is necessary for LEO satellites to be useful.
these satellites are very useful in tasks like observation of earth.
. LEO is used for military spy satellites to keep a watchful eye on other countries.
LEO satellites can collect data about the oceans for climate and ecological studies.
change in weather conditions can be estimated with LEO satellites.
 they can survey the land in the hunt for minerals and oil.

Medium Earth Orbit (MEO)

MEO - Medium Earth Orbit :

The advanced satellites are made with more features when compared to that of LEO satellites. They are MEO satellites.
They  locates  in orbit somewhere between 8,000 km and 18,000 km above the earth’s surface. 

these satellites are similar to LEO satellites in functionality.

MEO satellites are visible for much longer periods of time than LEO satellites, usually between 2 to 8 hours.
MEO satellites have a larger coverage area than LEO satellites.