Font size
WorksheetsWave Propagation Quiz
Total questions: 20
Worksheet time: 1hrs 5mins
Highest frequency that can be propagated directly upward and still be returned to Earth by the ionosphere.
Critical frequency
Critical frequency
Maximum Usable Frequency (MUF)
Optimum Working Frequency (OWF)
Operating at a frequency of 85% of the MUF provides more reliable communications
Critical frequency
Critical frequency
Maximum Usable Frequency (MUF)
Optimum Working Frequency (OWF)
Highest frequency that can be used for sky wave propagation between two specific points on Earth’s surface.
Critical frequency
Critical frequency
Maximum Usable Frequency (MUF)
Optimum Working Frequency (OWF)
Define as the loss incurred by an electromagnetic waves as it propagates in a straight line through a vacuum with no absorption or reflection of energy from nearby objects.
Attenuation
Fading
Spreading loss
Free-space path loss
Variation in signal loss.
Attenuation
Fading
Spreading loss
Free-space path loss
Disadvantages of surface waves.
Ground waves require a relatively transmission power.
Ground waves are limited to very low, low, and medium frequencies.
Requiring large antennas
Ground losses vary considerably with surface material and composition.
Advantages of ground wave propagation.
Given enough transmit power, ground waves can be used to communicate between any two locations in the world.
Ground waves are relatively unaffected by changing atmospheric conditions.
Ground waves are used to cover short ranges and therefore not affected by attenuation of waves.
Ground waves are limited to very low frequency signal. Hence, these require small antenna.
Semirough surface will reflect as if it were a smooth surface whenever the cosine of the angle of incidence is greater than λ/8d, where d is the depth of the surface irregularity and λ is the wavelength of the incident wave.
Rayleigh criterion
Huygen's Principle
Power Transfer in Free Space
Optical Principles
Earth –guided electromagnetic wave that travels over the surface of earth.
Surface wave
Sky waves
Direct waves
Terrestial waves
Electromagnetic waves travelling within Earth’s atmosphere.
Surface wave
Sky waves
Direct waves
Terrestial waves
Used for high-frequency applications.
Surface wave
Sky waves
Direct waves
Terrestial waves
Travel essentially in a straight line between the transmit and receive antennas.
Surface wave
Sky waves
Direct waves
Terrestial waves
Propagation of electromagnetic waves often called radio-frequency (RF) propagation or simply radio propagation.
Electromagnetic wave
Electric fields
Magnetic Field
Polarization
It is defined as the power radiated by an antenna in its favored direction, taking the gain of the antenna into account
EIRP (EFFECTIVE ISOTROPIC RADIATED POWER)
POWER GAIN
DIRECTIVE GAIN
ANTENNA EFFICIENCY
It is the ratio of the power radiated by the antenna to the power delivered to the feedpoint.
EIRP (EFFECTIVE ISOTROPIC RADIATED POWER)
POWER GAIN
DIRECTIVE GAIN
ANTENNA EFFICIENCY
A critical frequency at a particular time is 11.6 MHz. What is the MUF for a transmitting station if the required angle of incidence for propagation to a desired destination is 70 degrees?
(a)
A 500 kHz antenna radiate 500W of power. The same antenna produces a field strength equal to 1.5 mV/m. If the power delivered by the antenna is increased to 250 W, what would be the expected filed intensity.
(a)
A power of 100 W is supplied to an isotropic radiator. What is the power density and the field strength at a point 10 km away?
(a)
Suppose that the transmitter and receiver towers have equal height. How high would they have to be to communicate over a distance of 40 km?
(a)
A power of 100 W is supplied to an isotropic radiator. What is the power density at a point 10 km away?
(a)
