Neets Module 10 Ch2

Front 1

which two composite fields (Electric field and the Magnetic field) are associated with every antenna?

Back 1

induction field and radiation field

Front 2

which composite field is stored with in the antenna?

Back 2

induction field

Front 3

which composite field in emitted into free space?

Back 3

radiation field

Front 4

what term is used to describe the basic frequency of a wave?

Back 4

fundamental frequency

Front 5

what term is used to describe the whole number multiple of the basic frequency of a radio wave?

Back 5

harmonic frequency

Front 6

It is known that WWV operates and 10 Mhz what is the wavelength of WWV?

Back 6

30 meters

Front 7

A station is know to operate at a wavelength of 60 meters what is the frequency of the station?

Back 7

5 Mhz

Front 8

if an antenna is place close to the ground, how should the antenna be polarized to give it the bast signal strength?

Back 8

vertically polarized

Front 9

In the right rule of propagation the thumb points in the direction of the E field, and the forefinger points in the direction of the H field. In what direction does the middle finger represent?

Back 9

direction of the wave of propagation

Front 10

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

Back 10

shifting in the face relationship of the wave

Front 11

What are the three layers of the atmosphere

Back 11

troposphere, stratosphere, and ionoshere

Front 12

what layer of the atmosphere has little affect on radio waves?

Back 12

stratosphere

Front 13

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

Back 13

whether the wave is traveling along the surface of the earth or over the surface of the earth

Front 14

what is the best type of terrain or surface to transmit a radio wave?

Back 14

sea water

Front 15

what is the primary difference between radio horizon and the natural horizon?

Back 15

the radio horizon is 1/3 times farther than the natural horizon

Front 16

what three factors must be considered in the transmission of the surface wave to reduce attenuation?

Back 16

the electrical properties of the terrain, frequency, and the polarization of the antenna

Front 17

What causes ionization in the atmosphere?

Back 17

high energy ultraviolet light waves from the sun enter the ionospheric region of the atmosphere, strike a gas atom, and literally knock an electron free from its parent atom

Front 18

How are the four distinct layer in the ionosphere designated

Back 18

they are designated D, E, F1 and F2

Front 19

What are the heights of the individual layers of the ionosphere?

Back 19

D layer is 30-55 miles, the E layer is 55-90 miles, the F layers are 90-240

Front 20

what factor determines whether a radio wave is deflected or refracted by the ionosphere?

Back 20

the thickness of the ionized layer

Front 21

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

Back 21

critical frequency

Front 22

what three factors determine the amount of refraction in the ionosphere?

Back 22

depends on the frequency of the wave, the
angle of incidence, and the degree of ionization present.

Front 23

what is the skip zone of a radio wave?

Back 23

a zone of silence where the ground wave becomes to weak for reception and the point where the sky wave first returns to earth

Front 24

where does the greatest amount of absorption occur in the ionosphere

Back 24

most ionospheric absorption occurs in the lowest layers of the ionosphere where ionization density is greatest

Front 25

what is meant by the term multipath?

Back 25

a term used to describe the multiple paths of a radio wave between the transmitter and receiver

Front 26

when a wide band of frequencies is transmitted simultaneously, each frequency will vary in the amount of fading, what is this called?

Back 26

selective fading

Front 27

what are the two types of EMI radio waves have to deal with?

Back 27

man made and natural

Front 28

Thunderstorms, snowstorms, cosmic sources, the sun, etc., are a few examples of emi sources.
What type of emi comes from these sources?

Back 28

natural

Front 29

Motors, switches, voltage regulators, generators, etc., are a few examples of emi sources. What
type of emi comes from these sources?

Back 29

man-made

Front 30

. What are three ways of controlling the amount of transmitter-generated emi?

Back 30

EMI can be controlled by cutting transmitting antennas to the correct frequency, limiting bandwidth , and electronic filtering networks and metallic shielding

Front 31

What are three ways of controlling radiated emi during transmission?

Back 31

the physical separation of the transmitting and receiving antennas, the use of directional antennas, and limiting antenna bandwidth

Front 32

what are two general types of variation in the ionosphere?

Back 32

regular and irregular variations

Front 33

what is the main difference between the two variations?

Back 33

Regular is predictable and can be anticipated
Irregular is unpredictable

Front 34

What are the four main classes of regular variation which affect the extent of ionization in the
ionosphere?

Back 34

Daily, seasonal, 11-year, and 27-days variation.

Front 35

What are the three more common types of irregular variations in the ionosphere?

Back 35

Sporadic E, sudden disturbances, and ionospheric storms.

Front 36

what do the letters muf, luf, and fot stand for

Back 36

maximum usable frequency, lowest usable frequency, and frequence optimum de travail.

Front 37

what is muf at its highest and why?

Back 37

muf is highest around noon due to the fact ultraviolet light rays from the sun are at there highest

Front 38

what happens to the radio wave if the luf is to low?

Back 38

As the frequency of a radio wave is lowered, the rate of refraction increases. So a wave whose frequency is below the established luf is refracted back to Earth at a shorter distance than desired

Front 39

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

Back 39

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

Front 40

what are some disadvantages of operating transmitters at or near the muf?

Back 40

Frequent signal fading and dropouts

Front 41

What is fot?

Back 41

Fot is the most practical operating frequency that can be relied on to avoid problems of multipath,
absorbtion, and noise.

Front 42

How do raindrops affect attenuation?

Back 42

They can cause attenuation by scattering

Front 43

How does fog affect radio waves at frequencies above 2 gigahertz?

Back 43

It can cause attenuation by absorbtion.

Front 44

How is the term "temperature inversion" used when referring to radio waves?

Back 44

It is a condition where layers of warm air are formed above layers of cool air.

Front 45

How does temperature inversion affect radio transmission?

Back 45

It can cause vhf and uhf transmission to be propagated far beyond normal line-of-sight distances.

Front 46

In what layer of the atmosphere does virtually all weather phenomena occur?

Back 46

Troposphere.

Front 47

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

Back 47

Vhf and above.

Front 48

Where is the tropospheric region that contributes most strongly to tropospheric scatter
propagation?

Back 48

Near the mid-point between the transmitting and receiving antennas, just above the radio horizon.