Finals Reviewer-Transline Complete

Teflon

This material is made up of polytetrafluoroethylene plastic with non-sticking properties and is commonly used as a dieletric material for ribbon wires

Attenuation Coefficient

IT transmission line parameter is used to determine the reduction in voltage and current with distance as TEM wave propagates down a transmission line

Permeability

The measure of the ability of a material to alter magnetic field in which it is placed

Balun

A circuit device used to interface a line operating in a differential signal transmission to another line operating in a single-ended signal transmission

Propagation Constant

It is used to express the amount of attenuation and phase shift per unit length of a transmission line

Twin Lead/ Two wire Ribbon Cable

one form of two-wire parallel conductor transmission line that is similar to open wire transmission line except that the spacers between conductors are replaced with continuous solid dielectric

Resonance

The state of oscillation that occurs at a specific frequency in an electrical circuit such as a transmission line because it consists of inductive and capacitive components

Time Quadrature

The time relationship between the electric and magnetic fields of an electromagnetic wave whereas the two occur repeatedly at 90 degrees apart in time

Longitudinal/Compression Wave

wave in which the direction of displacement the same as the direction of propagation

Wave Velocity/Speed

The rate of exchange in the position of an object as it moves in a particular direction along in a transmission line

Plasma

It is a hot ionized gas made up of ions and electrons that is found in the sun, star, and fusion reactors which is also a good conductor of electricity and reacts o a magnetic field

Conductor Loss/Copper Loss

This loss of electrical energy that is due to the collision of charges with the atoms of conductor

Open-Wire Line/Two-Wire Open Line

The type of transmission line whose primary disadvantages are high radiation losses and noise pickup but the dielectric is air

Phase Shift

In a transmission line, this electrical parameter represent the rate at which the wave oscillate as a function of position on the line

Electrical Length

The length of a transmission line relative to the length of the wave propagating down on it

Inductor

The behavior of an open transmission line whose length is between 0.25 λ and 0.5 λ

Reflection Coefficient

It describes either the amplitude or intensity of a reflected wave relative to the incident wave

Standing Wave

It is produced when the incident and reflected waves passes it each other creating the stationary pattern of voltage or current along the line

Angle of Reflection Coefficient

The transmission line parameter that describe the phase relation ship between the incident and reflected waves

Non-Resonant Line/Untuned Line/Flat line

The term used to describe a transmission line with no reflected energy or power

Node

Another term used to describe the minima of standing wave pattern

L Hospital's Rule/Bernoulli's Rule

A mathematical tool that uses derivatives to help evaluate limits involving indeterminate forms in solving input impedances.

Standing Wave

The interference pattern that was set up as a result of incident waves and reflected waves traveling opposite directions in the transmission line

Input Impedance

For lossless line terminated in either an open or a shorted load, this transmission line characteristics can have a value that can simulate a resistor, an inductor or a capacitor depending on the distance from the load to the point of measurement

Input Impedance

The transmission line parameter that is the equivalent behavior of the line in an ideal condition where the line impedance is equal to the load impedance

Ionization

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

One-Third

a space wave is primarily a result of refraction in the troposphere and extends approximately by how much more distance beyond the optical horizon

Power Density

It is the rate at which energy from a radio wave is passed through a given surface in free space

Wavefront

The area from which a receiving antenna can be considered to extract all the energy in an electromagnetic wave

Isotropic Antenna/Point Source

A hypothetical antenna having zero physical size and no loss and radiating equally in all directions

Meteor Trail Propagation

A special type of wireless propagation utilizing the ionized trail of air particles left behind by meteors from space

Radio Horizon

An imaginary line in the farthest distance where the land or sea seems to meet the RF wave as presented by the curvature of the Earth to space wave propagation

Free Space Loss/ Space Attenuation

The term used to describe the signal loss that assumes an ideal vacuum atmosphere so that no electromagnetic energy is actually lost or dissipated, but merely spreads out as it propagates away from the source, resulting in lower power densities

Space Wave

It is mode of radio wave communication that is primarily a result of refraction in the troposphere and where it extends the communication distance beyond the horizon by approximately one-third farther

Ionospheric Sounding

It is radio signal measurement technique used to determine the critical frequency of radio waves in sky-wave propagation

Half-Wave Dipole, Dipole

This antenna element can be piece of wire that is cut in half and attached to the terminals of ahigh frequency ac generator is set so that each half of the wire is 1/4 wavelength of the output

Michael Faraday

He demonstrated the first experimented that involved the coupling of electricity and magnetism and showed their definitive relationship relationship even before the conceptualization of the electromagnetic theory

Broadside Array

The driven antenna array whose direction is at right angles to the plane of the array and radiates very little in the direction along the plane

Sparks

The nickname given to the wireless telegraph operators that uses the first practical wireless telegraph system that used a spark gap to create a much more intense electric impulse than possible by a regular telegraph key alone

Antenna

is an electrical device which converts electric currents into radio waves and vice versa

Marconi Antenna

The vertical monopole antenna or quarter wavelength antenna is also known by this alternative name

Antenna Efficiency

It is the ratio of the power radiated by an antenna to the sum of the power that was radiated and dissipated

Near Field

It is the region of radiation of a transmitting antenna that is often referred to as the induction field as radio waves tends to return to the transmitting antenna

Turnstile Antenna

A type of antenna that is formed by placing two half wave dipole at right angles to each other such that it makes each element 90 degrees out of phase with one another to form a omnidirectional radiation pattern

Absolute Radiation Pattern

If the antenna radiation pattern is plotted in terms of fixed field strength or power density at relative distance, it is known by this name

Frequency

It describes the rate at which the periodic oscillations of an electromagnetic wave repeat itself.

Frequency

Period

Time

Cycle

Transverse Electromagnetic Wave

A wave that makes the medium through which it travels vibrates in a direction at right angles to the direction of its travel.

Longitudinal Wave

Latitudinal Wave

Angular Wave

Transverse Electromagnetic Wave

Time Quadrature

The time relationship between the electric and magnetic fields of an electromagnetic wave whereas the two occur repeatedly at 90 degrees apart in time.

Space Quadrature

Transverse relationship

Time Quadrature

Quadratic relationship

Resonance

It is the state of oscillation that occurs at a specific frequency in an electrical circuit such as a transmission line because it consists of inductive and capacitive components.

Permeability

Permittivity

Resonance

Resistivity

Phase shift

In a transmission line, this electrical parameter represents the rate at which the waves oscillate as a function of position on the line.

Frequency

Resonance

Phase shift

Period

increases

As the frequency increases, the ac resistance of a wire:

increases

decreases

Stays the same

change periodically

Resistance

Which of the following electrical parameters is negligible at extremely high frequencies?

a. Resistance

c. Capacitance

b. Inductance

d. Letters b and c

In an impedance equal to Zo

Transmission line is considered to be non-resonant (flat) when it is terminated in which of the following ways?

a. In an impedance equal to Zo

c. In an inductive reactance greater than Zo

b. In an impedance that is infinite

d. In a capacitive reactance greater than Zo

Quarter-wavelength Transformer

It is used as a narrowband impedance matching device to match a transmission line primarily to purely resistive loads.

a. Balun

b. Shunted stub

c. Shorted stub

d. Quarter-wavelength Transformer

Stub

It is a short remaining part of something that is left after the main part has been removed or used.

a. Stub

b. Transformer

c. Balun

d. Reactive part of the load

Characteristic Impedance of the Line

The solution in determining the Characteristic Impedance of the Quarter-wavelength Transformer always involves what constant parameter?

a. Characteristic Impedance of the Line

b. Input Impedance of the Line

c. Impedance of the Complex load

d. Electrical Length of the Line

Purely resistive

The behavior of a shunted stub can be any of the following except for:

a. Purely capacitive

b. Purely resistive

c. Purely inductive

d. None of the rest

Complex that has a resistance equal to that of the line impedance

A series stub can match a complex load when placed only at a proper location on the line that is

b. Purely inductive

a. Purely capacitive

c. Complex that has a resistance equal to that of the line impedance

d. Complex that has a resistance opposite to that of the line impedance

1/2

The Smith chart represents what portion (multiple) of a wavelength?

a. 1

b. 1/2

c. 1/4

d.1/3

R=1

Which resistance circle passes through the prime center of the smith chart?

a. R=0

b. R=1

c. R=infinity

d. It depends

Narrowband balun

A bazooka balun is sometimes called

a. Narrowband balun

b. Low-frequency balun

c. Transformer balun

d. Both letters a and c

None of the above

Which of the following is not a dielectric material used in transmission lines?

a. Rubber

b. Mica

c. Polyvinyl chloride

d. None of the above

Polyethylene

. Which of the following was developed for coaxial cables to replace rubber and eliminate high-frequency losses associated with rubber insulators?

a. Teflon

b. Mica

c. Polyethylene

d. None of the above

Braid

It is the sleeve woven into a mesh that prevents radiation losses and also prevents external EMI as noise and radio interference from reaching the signal conductors in STP cables.

a. Foil

b. Braid

c. Outer cable jacket

d. Dielectric insulator

0

The outer perimeter of the Smith chart represents what value of resistance?

a. 0

b. 0.25

c. 0.5

d. 1.0

0.3333, 180 degrees

A transmission line for which α = 0, β= 1.5Π radian/meter and Zo = 100 ohms is operated at a frequency of 10 MHz. If the load is 50 ohms, find the reflection coefficient. *

a. 0.3333, 0 degrees

b. 0.3333, 45 degrees

c. 0.3333, 90 degrees

d. 0.3333, 180 degrees

42 watts

A generator matched to a line with a voltage coefficient of reflection equal to 0.4 transmits 50 watts into the line. How much power is actually absorbed by the load?

a. 42 watts

c. 58 watts

d. 80 watts

b. 20 watts

0.1564 λ

Determine the electrical length of an open-circuited shunted stub required to match a 75-ohm line to a 1/75 - j1/50 load admittance. *

c. 0.6564 λ

d. 0.5646 λ

a. 0.1465 λ

b. 0.1564 λ

Radiation efficiency

It is the ratio of the power radiated by an antenna to the sum of the power radiated and dissipated.

a. Radiation efficiency

b. Antenna efficiency

d. Effective radiated power

c. Antenna directivity

Marconi antenna

The Vertical Monopole antenna is also known as

a. Half-wave dipole

b. Hertz antenna

c. Marconi antenna

d. Both letters a & b

L. Periodic

Which among the following is not a contributor to the development of the log-periodic

a. V. H. Rumsey

b. J. D. Dyson

c. R. H. DuHamel

d. L. Periodic

Guglielmo Marconi

He was the Italian electrical engineer that pioneered the practical development of radio signaling and shared a Nobel Prize for his work on wireless telegraphy and the quarter-wave antenna was named after him.

a. Heinrich Rudolf Hertz

b. Guglielmo Marconi

c. James Maxwell

d. Oliver Heaviside

Points of equal power density

In an absolute radiation pattern, the circular gradients represents:

a. Distance from the transmitter

b. Points of equal power density

d. Angle with respect to the transmitter

c. Direction of the major lobe

second antenna

Two antennas have gains of 6.4 dBi and 4.5 dBd, respectively. Which has greater gain?

a. first antenna

b. second antenna

d. none

c. they are equal

1.39

A dipole antenna has an efficiency of 85% and a directivity of 2.14dBi. Calculate its power gain.

a. 1.819 dBi

b. 1.43 dBd

c. 1.39

d. 1.43

0.7125m

Calculate the length of a half-wave dipole for an operating

frequency of 200 MHz if it is made 5% shorter than actual.

a. 1.5m

b. 0.75m

c. 1.425m

d. 0.7125m

Smith Chart

It is a 4-D representation of all possible complex impedance with respect to coordinates defined by the complex reflection coefficient.

a. Organizational Chart

b. Gamma Chart

c. Smith Chart

d. SWR Chart

Philip Smith

He developed a circular chart form that shows the entire universe of complex impedances in one convenient circle.

a. John Chart

b. John Smith

c. Philip Smith

d. Pepe Smith

Insulator

Leakage current in two-wire transmission line is the current that flows through what component?

a. Capacitor

b. Resistor

c. Dielectric

d. Insulator

Normalized Impedance

This concept was introduced in order to obtain universal curves of all

possible values of the complex impedance in the Smith Chart.

a. Load Impedance

d. Line Impedance

b. Input Impedance

c. Normalized Impedance

Rectangular

Load impedances are represented on the Smith chart in what form?

a. Rectangular

b. Polar

c. Trapezoidal

d. Parallel

Moving along the lossless transmission line is equivalent to moving around the gamma circle.

The following concepts are true regarding the Smith chart except for:

a. The lower half of the diagram represents negative reactance

b. The upper half of the diagram represents positive reactance

c. Moving along the lossless transmission line is equivalent to moving around the gamma circle.

d. A circle centered at the origin is a constant resistance circle

Diffraction

The bending of a radio wave because of achange in its velocity through a medium is known as

Ionosphere

Electrically charged particles that affectthe propagation of radio waves are foundin what atmospheric layer?

Troposphere

Most weather phenomena take place inwhich of the following region of theatmosphere?

Stratosphere

Radio wave propagation has the leasteffect because of its constancy on whichof the following atmospheric layers?

Space Wave

It is a mode of radio wave communication that is primarily a result of refraction in the troposphere and where it extends the communication distance beyond the horizon by approximately one-third farther.

a. Surface wave

b. Ground wave

c. Space wave

d. Sky wave

Space Wave

For long-range communications in the hfband, which of the following types ofwaves is most satisfactory?

Infrared Radiation (IR)

Ionization in the atmosphere is producedchiefly by which of the following types ofradiation?

Skip Distance

The distance between the transmitter andthe nearest point at which refracted wavesreturn to earth is referred to as the

Phase Relationships

Radio waves that arrive at a receiving sitealong different paths can cause signalfading if these waves have different

a. Velocities

d. Modulation percentages

b. Amplitudes

c. Phase relationships

Man made Interference

Receiving sites located near industrialareas can expect to have exceptionallylarge losses in signal quality as a result ofwhich of the following propagationsituations?

Space

The technique of reducing multipathfading by using several receiving antennasat different locations is known as whattype of diversity?

27-day sunspot cycle

Which of the following ionosphericvariation causes densities to vary with theaxial rotation of the sun?

Maximum usable frequency

For a radio wave entering the atmosphereof the earth at a given angle, the highestfrequency at which refraction will occur isknown by which of the following terms?

Optimum working frequency

The most consistent communications canbe expected at which of the followingfrequencies?

Scattering

At frequencies above 100 MHz, thegreatest attenuation of rf energy fromraindrops is caused by which of thefollowing factors?

Front-to-back ratio

The ratio of energy radiated by an arrayin the principal direction of radiation tothe energy radiated in the oppositedirection describes which of thefollowing relationships?

Multielement parasitic

The Yagi antenna is an example of whattype of antenna array?

1/8 to 1/4 wavelength

What is the range of electrical spacingbetween the elements of an end-firearray?