part 1

Question 1

What is the purpose of AC&W radar?

Answer 1

To control friendly aircraft, detect hostile aircraft, and control interceptors

Question 2

What is the purpose of the PAR?

Answer 2

To assist aircraft in making safe landings during poor weather conditions.

Question 3

What does the “T” in TPN–19 designate?

Answer 3

Transportable

Question 4

What is used with proper receiving equipment to detect the presence of a distant object?

Answer 4

Reflected energy

Question 5

At what speed do radio waves travel?

Answer 5

The speed of light, or 162,000 nautical miles per second

Question 6

How long does it take a radar pulse to travel one radar mile?

Answer 6

12.36 μs.

Question 7

What radar assembly supplies timing signals to coordinate the operation of the complete system?

Answer 7

Synchronizer

Question 8

An effective modulator pulse must perform what?

Answer 8

1. Fall from its maximum value to zero almost
   instantaneously.
2. Rise from zero to its maximum value almost
   instantaneously.
3. Remain at its maximum value for the duration of the
   transmitted RF pulse

Question 9

what are the two types of modulators ?

Answer 9

1. line pulsing modulator

2. hard tube modulator

Question 10

what does the line pulsing modulator do?

Answer 10

stores energy and forms pulses in the
same circuit element.
(stores energy and forms pulses in the
same circuit element.)

Question 11

what does the hard tube modulator do?

Answer 11

The hard-tube modulator

forms the pulse in the driver; the pulse is then amplified and applied to the modulator

Question 12

what is the most used modulator

in modern radar?

Answer 12

line pulsing modulator

Question 13

what are the two general classes of antenna?

Answer 13

omnidirectional and directional

Question 14

how do directional antennas radiate RF?

Answer 14

Directional antennas radiate RF
energy in patterns of lobes or beams that extend outward from the antenna in one direction for a given
antenna position.

Question 15

how do omnidirectional antennas radiate RF?

Answer 15

Omnidirectional antennas

radiate RF energy in all directions simultaneously

Question 16

what are the two important characteristics of directional antennas ?

Answer 16

directivity and power gain.

Question 17

When a transmitter uses a high-power oscillator to produce the output pulse, what switches the
oscillator on and off?

Answer 17

Modulator high voltage pulse

Question 18

What radar component permits the use of a single antenna for both transmitting and receiving?

Answer 18

Duplexer

Question 19

What are the two basic types of transmitters?

Answer 19

Keyed oscillator and power amplifier chain

Question 20

In addition to a flat top, what characteristics must a modulator pulse have?

Answer 20

Steep leading and trailing edges.

Question 21

What is the frequency range of magnetron oscillators?

Answer 21

600-30,000 MHz.

Question 22

What three types of storage elements are most often used in modulators?

Answer 22

1

Question 23

What type of tube best meets the requirements of a modulator switching element?

Answer 23

1

Question 24

What modulator element controls the rate at which the storage element charges?

Answer 24

1

Question 25

What two forms of instability are common in magnetrons?

Answer 25

1

Question 26

What is the typical frequency range about the center frequency of a tunable magnetron?

Answer 26

1

Question 27

In the power amplifier (shown in figure 1–10), what two signals are mixed to produce the output?

Answer 27

1

Question 28

What type of klystron is used as the final stage of a power amplifier transmitter?

Answer 28

1

Question 29

What is the result of pulsing a pulsed RF amplifier when no RF is present?

Answer 29

1

Question 30

What are the two general classes of antennas?

Answer 30

1

Question 31

What determines the width of the antennas main lobe?

Answer 31

1

Question 32

What is the directivity of a directional antenna?

Answer 32

1

Question 33

What are the two functions of a horn radiator?

Answer 33

1

Question 34

What are the functions of the antenna on transmit?

Answer 34

1

Question 35

What does it mean if an antenna is reciprocal?

Answer 35

1

Question 36

Why are reflector antennas extremely important and practical devices for use in radar systems?

Answer 36

1

Question 37

Why is the paraboloid shape useful?

Answer 37

1

Question 38

What happens when you change the physical shape of the antenna?

Answer 38

1

Question 39

How can you provide an amount of control over the received beam pattern?

Answer 39

1

Question 40

What is the purpose of the passive feedhorn?

Answer 40

1

Question 41

What is an advantage of using MTI?

Answer 41

1

Question 42

How is range gating adjusted in the 12-feedhorn system?

Answer 42

1

Question 43

Why is stacked-beam a good technique?

Answer 43

1

Question 44

How many receivers are used for the pencil beam?

Answer 44

1

Question 45

How does the gain of the individual pencil beams compare to the fan-beam antenna?

Answer 45

1

Question 46

What phase-array ability is an important advantage if the required antenna is large?

Answer 46

1

Question 47

How does the two-dimensional planer array work in rectangular form; in circular aperture form?

Answer 47

1

Question 48

What is the greatest limiting factor in a receiver’s detectable range?

Answer 48

1