Key Topic 47: Equipment Faults-4

Question 1

8-47F1: If the magnetron is allowed to operate without the magnetic field in place:

A. Its output will be somewhat distorted.
B. It will quickly destroy itself from excessive current flow.
C. Its frequency will change slightly.
D. Nothing serious will happen.

Answer 1

B. It will quickly destroy itself from excessive current flow.

Question 2

8-47F2: Targets displayed on the RADAR display are not on the same bearing as their visual bearing. What should you first suspect?

A. A bad reed relay in the antenna pedestal.
B. A sweep length misadjustment.
C. One phase of the yoke assembly is open.
D. Incorrect antenna position information.

Answer 2

D. Incorrect antenna position information.

Question 3

8-47F3: Loss of distant targets during and immediately after wet weather indicates:

A. A leak in waveguide or rotary joint.
B. High atmospheric absorption.
C. Dirt or soot on the rotary joint.
D. High humidity in the transmitter causing power supply loading.

Answer 3

A. A leak in waveguide or rotary joint.

Question 4

8-47F4: In a marine RADAR set, a high VSWR is indicated at the magnetron output. The waveguide and rotary joint appear to be functioning properly. What component may be malfunctioning?

A. The magnetron.
B. The waveform generator.
C. The STC circuit.
D. The waveguide array termination.

Answer 4

D. The waveguide array termination.

Question 5

8-47F5: On a vessel with two RADARs, one has a different range indication on a specific target than the other. How would you determine which RADAR is incorrect?

A. Check the sweep and timing circuits of both indicators for correct readings.
B. Triangulate target using the GPS and visual bearings.
C. Check antenna parallax.
D. Use the average of the two indications and adjust both for that amount.

Answer 5

A. Check the sweep and timing circuits of both indicators for correct readings.

Question 6

8-47F6: An increase in the deflection on the magnetron current meter could likely be caused by:

A. Insufficient pulse amplitude from the modulator.
B. Too high a B1 level on the magnetron.
C. A decrease of the magnetic field strength.
D. A lower duty cycle, as from 0.0003 to 0.0002.

Answer 6

C. A decrease of the magnetic field strength.