Fcc Grol Element 3O

Front 1

3-90O4

Shipboard RADAR is most commonly operated in what band?

Back 1

SHF

Front 2

3-90O5

The pulse repetition rate (prr) of a RADAR refers to the:

Back 2

Pulse rate of the magnetron

Front 3

3-90O6

If the elapsed time for a RADAR echo is 62 microseconds, what is the distance in nautical miles to the object?

Back 3

5 nautical miles

Front 4

3-90O1

What is the normal range of pulse repetition rates?

Back 4

500 to 2,000 pps

Front 5

3-90O2

The RADAR range in nautical miles to an object can be found by measuring the elapsed time during a RADAR pulse and dividing this quantity by:

Back 5

12.346 µs

Front 6

3-90O3

What is the normal range of pulse widths?

Back 6

.05 s to 1.0 s.

Front 7

3-91O1

The ATR box:

Back 7

Prevents the received signal from entering the transmitter

Front 8

3-91O2

What is the purpose or function of the RADAR duplexer/circulator? It is a/an:

Back 8

Electronic switch that allows the use of one antenna for both transmission and reception

Front 9

3-91O3

What device can be used to determine the performance of a RADAR system at sea?

Back 9

Echo box

Front 10

3-91O4

What is the purpose of a synchro transmitter and receiver?

Back 10

Transmits the angular position of the antenna to the indicator unit

Front 11

3-91O5

Digital signal processing (DSP) of RADAR signals (compared with analog) causes:

Back 11

Improved weak signal or target enhancement

Front 12

3-91O6

The component or circuit providing the transmitter output power for a RADAR system is the:

Back 12

Magnetron

Front 13

3-92O1

When a RADAR is being operated on the 48 mile range setting, what is the most appropriate pulse width (PW) and pulse repetition rate (pps)?

Back 13

1.0 s PW and 500 pps

Front 14

3-92O2

When a RADAR is being operated on the 6 mile range setting what is the most appropriate pulse width and pulse repetition rate?

Back 14

0.25 s PW and 1,000 pps

Front 15

3-92O3

We are looking at a target 25 miles away. When a RADAR is being operated on the 25 mile range setting what is the most appropriate pulse width and pulse repetition rate?

Back 15

1.0 s PW and 500 pps

Front 16

3-92O4

What pulse width and repetition rate should you use at long ranges?

Back 16

Wide pulse width and slow repetition rate

Front 17

3-92O5

What pulse width and repetition rate should you use at short ranges?

Back 17

Narrow pulse width and fast repetition rates

Front 18

3-92O6

When a RADAR is being operated on the 1.5 mile range setting, what is the most appropriate pulse width and pulse repetition rate?

Back 18

0.05 s PW and 2,000 pps

Front 19

3-93O1

How does the gain of a parabolic dish antenna change when the operating frequency is doubled?

Back 19

Gain increases 6 dB

Front 20

3-93O2

What type of antenna or pickup device is used to extract the RADAR signal from the wave guide?

Back 20

J-hook

Front 21

3-93O3

What happens to the beamwidth of an antenna as the gain is increased? The beamwidth:

Back 21

Decreases as the gain is increased

Front 22

3-93O4

A common shipboard RADAR antenna is the:

Back 22

Slotted array

Front 23

3-93O5

Conductance takes place in a waveguide:

Back 23

Through electromagnetic and electrostatic fields in the walls of the waveguide

Front 24

3-93O6

To couple energy into and out of a waveguide use:

Back 24

A thin piece of wire as an antenna

Front 25

3-94O1

The permanent magnetic field that surrounds a traveling-wave tube (TWT) is intended to:

Back 25

Prevent the electron beam from spreading

Front 26

3-94O2

Prior to testing any RADAR system, the operator should first:

Back 26

Assure no personnel are in front of the antenna

Front 27

3-94O3

In the term “ARPA RADAR,” ARPA is the acronym for which of the following?

Back 27

Automatic RADAR Plotting Aid

Front 28

3-94O4

Which of the following is NOT a precaution that should be taken to ensure the magnetron is not weakened:

Back 28

Keep the TR properly tuned.

Front 29

3-94O5

Exposure to microwave energy from RADAR or other electronics devices is limited by U.S. Health Department regulations to _______ mW/centimeter.

Back 29

5.0

Front 30

3-94O6

RADAR collision avoidance systems utilize inputs from each of the following except your ship’s:

Back 30

Anemometer