Module 1 - Electronics Systems and Technologies

Question 1

Which of the following is not a part of a complete antenna system?

• coupling device
• feeder
• director
• antenna

Answer 1

director

Question 2

Which of the following is not a factor in determining the type, size, and shape of the antenna?

• characteristic impedance of the transmission line used
• general direction of the receiving set
• amount of power to be radiated
• frequency of operation of transmitter

Answer 2

characteristic impedance of the transmission line used

Question 3

The property of interchangeability of the same antenna for transmitting and receiving is known as _____

• antenna reciprocity
• antenna duplexing
• antenna reversal
• antenna duplexing

Answer 3

antenna reciprocity

Question 4

What is the term used to identify the points of high current and high voltage on an antenna?

Answer 4

loop

Question 5

The ratio between the amounts of energy propagated in these directions compared to the energy that would be propagated if the antenna were not directional is known as __________

Answer 5

antenna gain

Question 6

What type of antenna can be used if communications must take place from a moving vehicle?

Answer 6

vertical antennas

Question 7

What type of polarization does VHF and UHF transmission use?

Answer 7

horizontal

Question 8

What type of polarization does MF and HF transmission use?

Answer 8

vertical

Question 9

This refers to a type of radiation that radiate energy equally in all direction

Answer 9

isotropic radiation

Question 10

This refers to the assumed resistance that would dissipate the same amount of power that the antenna takes to radiate the energy.

Answer 10

radiation resistance

Question 11

Radiation resistance is always measured at _____________

Answer 11

current loop

Question 12

What is the radiation resistance of an antenna in free space that is entirely removed from any objects that might affect its operation?

Answer 12

73 ohms

Question 13

Which of the following is NOT an indication that a person has received a severe electric shock?

Answer 13

rigor mortis

Question 14

This refers to a plot of the radiated energy from an antenna.

Answer 14

radiation pattern

Question 15

This refers to the range of frequencies over which the antenna can operate correctly.

Answer 15

bandwidth

Question 16

This refers to the ability of an antenna to focus energy in a particular direction when transmitting, or to receive energy from a particular direction when receiving.

Answer 16

directivity

Question 17

In an antenna radiation pattern, this refers to a zone in which the effective radiated power is at a minimum.

Answer 17

null

Question 18

Which of the following is not true about the grounded end of the quarter-wave antenna?

• has a high impedance
• has high current
• has low voltage
• has a low input impedance

Answer 18

has a high impedance

Question 19

What is the purpose of a ground screen in vertical quarter-wave antennas?

• All of these are correct
• reduce losses in the ground in the immediate vicinity of the antenna
• serves as protection of the antenna from contaminants in the ground
• prevents electric shock for personnel working under the antenna

Answer 19

reduce losses in the ground in the immediate vicinity of the antenna

Question 20

This serves the same purpose as the ground screen, but it is usually elevated above the earth and used when the earth is not a good conducting surface, such as ground that is sandy or solid rock.

Answer 20

counterpoise

Question 21

Which of the following describes the physical arrangement of a ground screen?

Answer 21

composed of a series of conductors arranged in a radial pattern and buried 1 to 2 feet below the ground.**

Question 22

This refers to an ordinary half-wave antenna that has one or more additional conductors connected across its ends.

Answer 22

folded dipole