Wave Prob

Question 0

What composite field (composed of E & H fields) is found stored in the antenna?

Answer 0

Induction field

Question 1

Which 2 composite fields are associated with every antenna?

Answer 1

Induction & radiation

Question 2

What composite field (composed of E & H fields) is propagated into free space.

Answer 2

Radiation

Question 3

What term is used to describe the basic freq. of a radio wave.

Answer 3

Fundamental freq

Question 4

What term is used to describe a whole # multiple of the basic freq of a radio wave.

Answer 4

Harmonic freq. or harmonics

Question 5

If a transmitting antenna is placed close to the ground how should the antenna be polarized to give the greatest signal strength.

Answer 5

Vertically.

Question 6

What is one of the major reasons for the fading of radio waves which have been reflected from a surface?

Answer 6

Shifting of the phase relationships if the wave

Question 7

What are the 3 layers if the atmosphere?

Answer 7

Troposphere
Stratosphere
Ionosphere

Question 8

Which layer of the atmosphere has little to no effect on radio waves?

Answer 8

Stratosphere

Question 9

What are the 2 components of a ground wave?

Answer 9

Surface & space wave

Question 10

What type of polarization is preferred for a surface wave?

Answer 10

Vertical

Question 11

What is the determining factor in classifying whether a radio wave is a ground wave or a space wave?

Answer 11

Whether the component is traveling along the surface or over the surface of the earth.

Question 12

What is the best type of surface or terrain to use for radio wave transmission.

Answer 12

Sea water

Question 13

What are the 3 factors that must be considered in the transmission if surface waves to reduce attenuation.

Answer 13

• Electrical properties of the terrain
• freq
• polarization of the antenna

Question 15

What is the hight of the D layer of the ionosphere.

Answer 15

30-55 miles

Question 16

What is the hight of the E layer of the ionosphere.

Answer 16

55-90 miles

Question 17

What is the hight of the F layers of the ionosphere.

Answer 17

90-240 miles

Question 18

What factor determines whether a radio wave is reflected or refracted by the ionosphere.

Answer 18

Thickness if ionized layer

Question 19

There is a maximum freq at which vertically transmitted radio waves can be refracted back to earth. What is this max freq called?

Answer 19

Critical freq

Question 20

What 3 main factors determine the amount of refraction in the ionosphere.

Answer 20

• Density of the ionized layer
• freq
• angle of entry

Question 21

What is the skip zone of a radio wave?

Answer 21

A zone of silence between the ground wave & sky wave where there is no reception.

Question 22

Where does the greatest amount of ionospheric absorption occur in the ionosphere?

Answer 22

Where the density is the greatest.

Question 23

What is meant by the term multipath?

Answer 23

Term used to describe the multiple pattern a radio wave may follow.

Question 24

What are the 4 main classes of regular variations which effect the ionization of the ionosphere.

Answer 24

• Daily
• seasonal
• 11 year
• 26 year

Question 25

What is luf?

Answer 25

Lowest usable freq

Question 26

What is muf?

Answer 26

Max usable freq

Question 27

What is fot?

Answer 27

Optimum working freq

Question 28

What happens when luf is to low?

Answer 28

The signal will be absorbed & to weak for reception.

Question 29

What are some disadvantages of operating transmitters at or near luf?

Answer 29

Signal-to-noise ratio is low and the probability of multipath propagation is greater

Question 30

What are some disadvantages of operating transmitters at or near muf?

Answer 30

Frequent signal fading & dropouts.

Question 31

How do raindrops affect radio waves?

Answer 31

Can cause attenuation by scattering.

Question 32

How does fog affect radio waves at freqs above 2 ghz?

Answer 32

Can cause attenuation by absorption.

Question 33

What layer of the atmosphere is weather?

Answer 33

Troposphere.

Question 34

Which radio freq bands use the tropospheric scattering principle for propagation of radio waves?

Answer 34

VHF & above.

Question 35

What is the primary difference between the radio horizon & the natural horizon.

Answer 35

Radio horizon is about 1/3 farther.