Question

Describe the basic difference between an active and passive satellite system. also discuss its merits and demerits.

Answer 1

Active Satellite : 
The active satellite has many benefits over passive satellite. 
• It has its own transmitting and receiving antennas. 
• It amplifies the signal received from earth station or ground station and retransmits the amplified signal back to earth. 
• In addition to amplification, it performs frequency translation of the received signal before retransmission. Active satellite can generate power for its own operation. 
• It is known as active repeater due to its functionality. 

Passive Satellite :
• The passive satellite is a reflector which receives the signal from the transmitting earth station and scatters the signal in all the directions.
• It reflects the EM radiation without any modification and and/or amplication.
• Passive satellite can not generate power of its own and simply reflects the incident power. 
• It is known as passive repeater due to its functionality. 

Answer 2

Active satellite:

• active satellite contains the transponder a processing equipment.
• it amplifies and re-transmits the signal from the earth and it have many advantages over the passive satellites.
• it require lower power from earth station.
• it is less costly.
• it cannot open to random use.
• it is controlled by operators from the ground.

Passive satellite:

• passive satellite does not contain any processing equipment.
• it require high power from the earth station.
• it is expensive in terms of tracking facilities.
• it can be open randomly by different users.
• it is not possible to control passive satellite form the ground.