Key Topic 96: INMARSAT Communications Systems-1

Question 1

3-96P1: What is the orbital altitude of INMARSAT Satellites?

A. 16,436 miles.
B. 22,177 miles.
C. 10,450 miles.
D. 26,435 miles.

Answer 1

B. 22,177 miles.

Question 2

3-96P2: Which of the following describes the INMARSAT Satellite system?

A. AOR at 35°W, POR-E at 165°W, POR-W at 155°E and IOR at 56.5°E.
B. AOR-E at 25°W, AOR-W at 85°W, POR at 175°W, and IOR at 56.5°E.
C. AOR-E at 15.5°W, AOR-W at 54°W, POR at 178°E, and IOR at 64.5°E.
D. AOR at 40°W, POR at 178°W, IOR-E at 109°E, and IOR-W at 46°E.

Answer 2

C. AOR-E at 15.5°W, AOR-W at 54°W, POR at 178°E, and IOR at 64.5°E.

Question 3

3-96P3: What are the directional characteristics of the INMARSAT-C SES antenna?

A. Highly directional parabolic antenna requiring stabilization.
B. Wide beam width in a cardioid pattern off the front of the antenna.
C. Very narrow beam width straight-p from the top of the antenna.
D. Omnidirectional.

Answer 3

D. Omnidirectional.

Question 4

3-96P4: When engaging in voice communications via an INMARSAT-B terminal, what techniques are used?

A. CODECs are used to digitize the voice signal.
B. Noise-blanking must be selected by the operator.
C. The voice signal must be compressed to fit into the allowed bandwidth.
D. The voice signal will be expanded at the receiving terminal.

Answer 4

A. CODECs are used to digitize the voice signal.

Question 5

3-96P5: Which of the following statements concerning INMARSAT geostationary satellites is true?

A. They are in polar orbit, in order to provide true global coverage.
B. They are in an equatorial orbit, in order to provide true global coverage.
C. They provide coverage to vessels in nearly all of the world’s navigable waters.
D. Vessels sailing in equatorial waters are able to use only one satellite, whereas other vessels are able to choose between at least two satellites.

Answer 5

C. They provide coverage to vessels in nearly all of the world’s navigable waters.

Question 6

3-96P6: Which of the following conditions can render INMARSAT-B communications impossible?

A. An obstruction, such as a mast, causing disruption of the signal between the satellite and the SES antenna when the vessel is steering a certain course.
B. A satellite whose signal is on a low elevation, below the horizon.
C. Travel beyond the effective radius of the satellite.
D. All of these.

Answer 6

D. All of these.