Wave Propagation

Question 1

composed of electric and magnetic field which are perpendicular to each other and to the direction of propagation

Answer 1

Transverse Electromagnetic Wave

Question 2

What are the four fundamental properties of EM waves?

Answer 2

Frequency, Polarization, Direction of propagation, Strength

Question 3

orientation of electric field radiated from antenna

Answer 3

Polarization

Question 4

direction of propagation where waves are perpendicular to the direction

Answer 4

Transverse

Question 5

direction of propagation where waves are parallel to the ditection

Answer 5

Longitudinal

Question 6

theoretical point source that radiates energy equally in all directions (omnidirectional). It has a transmitter gain of ___.

Answer 6

Power Density; 1

Question 7

amount of power of an isotropic antenna would need to be to radiate to produce the same power density in the direction of the maximum gain as the actual directional antenna.

Answer 7

Effective Isotropically Radiated Power (EIRP)

Question 8

reflection

Answer 8

Bouncing back of waves as it hits the surface

Question 9

states that each point on spherical wavefront can be a source of secondary wavefront

Answer 9

Huygen’s Principle

Question 10

• vertically polarized wave that travel along the earth surface
• effective up to 2 MHz
• used by VLF and MF band

Answer 10

Ground Wave/ Surface Wave

Question 11

• waves that travel in a straight path
• used by UHF band
• limited by: LOS, antenna height, earth bulge

Answer 11

Space Wave/Direct Wave/Tropospheric Propagation

Question 12

maximum distance you can see along the earth’s surface due to Earth’s surface due to line-of-sight limitations.

Answer 12

Optical horizon

Question 13

straight, unobstructed path between transmitter and receiver.

Answer 13

Light of Sight (LOS)

Question 14

maximum distance over which a radio signal can be received via line-of-sight, considering the earth’s curvature and atmospheric refraction

Answer 14

Radio Horizon

Question 15

effective Earth radius factor

Answer 15

k factor

Question 16

waves that are reflected (but actually refracted) from the ionosphere.

Answer 16

Sky Wave/Ionospheric Propagation

Question 17

also known as the E Layer

Answer 17

Kennelly-Heaviside Layer

Question 18

also known as the F2 layer

Answer 18

Appleton Layer

Question 19

Highest frequency given ionization density that will be returned down to the earth when beamed vertically upward

Answer 19

Critical Frequency

Question 20

highest angle at which the wave can be propagated and still be returned to earth from the ionosphere

Answer 20

Critical Angle

Question 21

highest frequency which is returned to earth at a given distance

Answer 21

Maximum Useable Frequency (MUF)

Question 22

shortest distance at which sky wave signal will be returned to earth measured along the surface of the earth

Answer 22

skip distance

Question 23

zone of silence beyond the reach of the ground wave but is closer than the nearest point where the sky wave returns to earth.

Answer 23

Skip Zone

Question 24

Transmission of radio waves far beyond LOS distance by using high power and large transmission antenna to beam the signal upward into the atmosphere and similar large receiving antenna to pick-up the portion of the signal that is scattered by the atmosphere

Answer 24

Scatter Propagation/Beyond or Over the Horizon Communication/Forward Scatter Propagation

Question 25

causes channels or ducts of layers of warm air form above layers of cold air or layer of cool air becomes sandwiched between two layers of warmer air, which can cause radio waves to travel far beyond the normal LOS distances.

Answer 25

Temperature Inversion

Question 26

amount of attenuation in the power of the signal emitted from transmitting station till it arrives at the reception point

Answer 26

Propagation Loss

Question 27

most effective frequency for ionospheric reflection of radio waves between two specified points on earth; most practical operating frequency

Answer 27

optimum working frequency

Question 28

skip distance is determined by:

Answer 28

height of the ionosphere and angle of radiation