š Key Concepts
ā¢ INMARSAT-B uses higher bandwidth voice/data services and typically requires a mechanically steered, directional (parabolic) antenna aimed at the satellite.
ā¢ INMARSAT-C is a lower dataārate messaging system that commonly uses a small, fixed, omni-directional antenna.
ā¢ Think about how antenna size and directionality (parabolic vs omni) usually relate to gain, complexity, and the need to track the satellite.
š Think About
ā¢ Which system (B or C) would more likely need a larger, mechanically steered, highāgain antenna to support wideband services like voice and fax?
ā¢ Which system is designed for simple, lowārate data and messaging, and so can use a smaller, fixed antenna that does not need to be steered?
ā¢ Look at each option and ask: does it correctly pair the highāgain parabolic antenna with the higher bandwidth system, and the small omni antenna with the lower bandwidth messaging system?
ā
Before You Answer
ā¢ Make sure you correctly match directional/parabolic antennas with the system that needs higher gain and satellite tracking.
ā¢ Confirm that the system designed for simple, lowārate messaging is described as having a small, omni-directional antenna.
ā¢ Eliminate any choice where the description of antenna size vs function (gain/bandwidth) does not make practical engineering sense.