Radar Observer Unlimited - Theory Questions

The description "RACON" beside an illustration on a chart would mean a _________.

• radar conspicuous beacon

• circular radio beacon

• radar calibration beacon

• radar transponder beacon

Your radar has a beam width of 2°. The radar gyro bearing of the right tangent of an island is 316°. The gyro error is 1°E. Which true bearing should be plotted on the chart?

• 313°

• 314°

• 316°

• 317°

Coral atolls, or a chain of islands at right angles to the radar beam, may show as a long line rather than as individual targets due to __________.

• the pulse length of the radar

• limitations on range resolution

• the multiple-target resolution factor

• the effects of beam width

You are radar scanning for a buoy fitted with a RACON. In illustration D017NG below, which radar screen represents the presentation you should expect on the PPI?

• A

• B

• C

• D

A radar display which is oriented, so that north is always at the top of the screen, is called a(n) .

• relative display

• unstabilized display

• stabilized display
• composite display

The beam width of your radar is 2°. The left tangent bearing of a small island, as observed on the PPI scope, is 056°pgc. If the gyro error is 2°E, what bearing would you plot on the chart?

• 052°

• 056°

• 059°

• 060°

Illustration D011NG below represents the geographic location of a vessel and the radar presentation at the same time. Which statement is TRUE?

• A. A tangent bearing of the headland to the south-southeast should be corrected by adding one-half of the beam width.

• B. Ship No. 1 is not detected due to the shadow effect of the headland.

• C. The small island is not detected due to the effect of beam width.

• D. Ship No. 2 is not detected due to the reflective mass of the background mountain overpowering the ship's reflective signals.

You have another ship overtaking you close aboard to starboard. You have 3 radar targets bearing 090° relative at ranges of .5 mile, 1 mile, and 1.5 miles. In this case, the unwanted echoes are called .

• multiple echoes
• indirect echoes

• spoking

• side-lobe echoes

An indirect radar echo is caused by a reflection of the main lobe of the radar beam off the observer's vessel. Which of the following is NOT a characteristic of indirect echoes?

• Their bearing is almost constant, even when the true bearing of the contact changes appreciably.

• They always appear on a bearing of 90° from the true bearing of the contact.

• When plotted, their movements are usually abnormal.

• The indirect echoes usually appear in shadow sectors.

Illustration D011NG below represents the geographic location of a vessel and the radar presentation at the same time. Which statement is TRUE?

• A. A tangent bearing of the headland to the south-southeast is corrected by subtracting one-half of the beam width.

• B. Ship No. 2 is not detected due to the side lobe effect of radar reflecting from the mountain.

• C. Ship No. 1 does not appear as an individual target due to the effect of beam width.

• D. Small island is not detected due to the multiple echo effect from the mountain.