Key Topic 39: Antenna Systems

Question 1

8-39E1: Slotted waveguide arrays, when fed from one end exhibit:

A. Frequency scan.
B. High VSWR.
C. Poor performance in rain.
D. A narrow elevation beam.

Answer 1

A. Frequency scan.

Question 2

8-39E2: A typical shipboard RADAR antenna is a:

A. Rotary parabolic transducer.
B. Slotted waveguide array.
C. Phased planar array.
D. Dipole.

Answer 2

B. Slotted waveguide array.

Question 3

8-39E3: Good bearing resolution largely depends upon:

A. A high transmitter output reading.
B. A high duty cycle.
C. A narrow antenna beam in the vertical plane.
D. A narrow antenna beam in the horizontal plane.

Answer 3

D. A narrow antenna beam in the horizontal plane.

Question 4

8-39E4: The center of the transmitted lobe from a slotted waveguide array is:

A. Several degrees offset from a line perpendicular to the antenna.
B. Perpendicular to the antenna.
C. Maximum at the right hand end.
D. Maximum at the left hand end.

Answer 4

A. Several degrees offset from a line perpendicular to the antenna.

Question 5

8-39E5: How does antenna length affect the horizontal beamwidth of the transmitted signal?

A. The longer the antenna the wider the horizontal beamwidth.
B. The longer the antenna the narrower the horizontal beamwidth.
C. The horizontal beamwidth is not affected by the antenna length.
D. None of the above.

Answer 5

B. The longer the antenna the narrower the horizontal beamwidth.

Question 6

8-39E6: What is the most common type of RADAR antenna used aboard commercial maritime vessels?

A. Parabolic.
B. Truncated parabolic.
C. Slotted waveguide array.
D. Multi-element Yagi array.

Answer 6

C. Slotted waveguide array.