Description : What are some disadvantages of operating transmitters at or near the luf?
Last Answer : Signal-to-noise ratio is low and the probability of multipath propagation is greater.
Description : What do the letters muf, luf, and fot stand for?
Last Answer : Muf is maximum usable frequency. Luf is lowest usable frequency. Fot is commonly known as optimum working frequency.
Description : To obtain the most reliable sky wave propagation the ____ should be used. A. Lowest useable frequency (LUF). B. Maximum useable frequency (MUF). C. Optimum useable frequency (OUF). D. Critical frequency
Last Answer : C. Optimum useable frequency (OUF).
Description : What is the skip zone of a radio wave?
Last Answer : A zone of silence between the ground wave and sky wave where there is no reception.
Description : What factor determines whether a radio wave is reflected or refracted by the ionosphere?
Last Answer : Thickness of ionized layer.
Description : What is the best type of surface or terrain to use for radio wave transmission?
Last Answer : Radio horizon is about 1/3 farther.
Description : What is the determining factor in classifying whether a radio wave is a ground wave or a space wave?
Last Answer : Whether the component of the wave is travelling along the surface or over the surface of the earth.
Description : What is the term used to describe the basic frequency of a radio wave?
Last Answer : Fundamental frequency.
Description : What is the term used to describe a whole number multiple of the basic frequency of a radio wave?
Last Answer : Harmonic frequency or harmonics.
Description : What happens to the electrons of a gallium-arsenide semiconductor when they move from the normal low-energy conduction band to the high-energy conduction band?
Last Answer : The electrons become immobile.
Description : Which radio frequency bands use the tropospheric scattering principle for propagation of radio waves?
Last Answer : Vhf and above
Description : How does temperature inversion affect radio transmission?
Last Answer : It can cause vhf and uhf transmission to be propagated far beyond normal line-of-sight distances.
Description : How is the term "temperature inversion" used when referring to radio waves?
Last Answer : It is a condition where layers of warm air are formed above layers of cool air.
Description : How does fog affect radio waves at frequencies above 2 gigahertz?
Last Answer : It can cause attenuation by absorbtion.
Description : How do raindrops affect radio waves?
Last Answer : They can cause attenuation by scattering.
Description : What are the two main sources of emi with which radio waves must compete?
Last Answer : Natural and man-made interference.
Description : There is a maximum frequency at which vertically transmitted radio waves can be refracted back to Earth. What is this maximum frequency called?
Last Answer : Critical frequency.
Description : What is the primary difference between the radio horizon and the natural horizon?
Last Answer : Sea water.
Description : Which layer of the atmosphere has relatively little effect on radio waves?
Last Answer : Stratosphere.
Description : What is one of the major reasons for the fading of radio waves which have been reflected from a surface?
Last Answer : Shifting in the phase relationships of the wave.
Description : What connecting link is used to transfer energy from a radio transmitter to its antenna located on
Last Answer : Transmission line.
Description : What is the main use of a radio teletypewriter?
Last Answer : High speed automatic communications across ocean areas.
Description : What type of amplifier would be used to amplify the signal from a radio antenna?
Last Answer : An rf voltage amplifier.
Description : Which subscript, in circular waveguide classification, indicates the number of full-wave patterns around the circumference?
Last Answer : First.
Description : The number of half-wave patterns in the "b" dimension of rectangular waveguides is indicated by which of the two descriptive subscripts?
Last Answer : Second.
Description : What is added to a sawtooth generator to produce a trapezoidal wave?
Last Answer : A resistor.
Description : Can a pure sine wave be integrated? Why?
Last Answer : A pure sine wave cannot be integrated; it contains no harmonics.
Description : What is the fundamental difference between the phase relationship of the harmonics of the square wave as compared to the harmonics of a peaked wave?
Last Answer : All the odd harmonics are in phase with the fundamental in the square wave. This is not true of the odd harmonics in the peaked wave.
Description : What is the peaked wave composed of?
Last Answer : It is composed of odd harmonics some of which are out phase with the fundamental.
Description : What type of bias (positive or negative) is added to a negative damper for the most positive extremity of the wave shape to be clamped above 0 volts?
Last Answer : Positive bias.
Description : A negative damper with negative bias clamps the most positive extremity of the output wave shape to what polarity (positive or negative)?
Last Answer : Negative potential.
Description : Which portion of a sine-wave input is retained in the output of a series-negative limiter?
Last Answer : Positive.
Description : Which portion of a sine-wave input is retained in the output of a series-positive limiter?
Last Answer : Negative.
Description : A sound wave that is reflected back toward the source is known as what type of sound?
Last Answer : Echo.
Description : A refracted wave occurs when a wave passes from one medium into another medium. What determines the angle of refraction?
Last Answer : The density of the two mediums, and the velocity of the waves.
Description : When a wave is reflected from a surface, energy is transferred. When is the transfer of energy greatest?
Last Answer : When the incident wave is nearly parallel with the surface.
Description : What are the three requirements for a wave to be propagated?
Last Answer : A source, medium, and detector (receiver).
Description : What example of a longitudinal wave was given in the text?
Last Answer : A sound wave.
Description : What type of wave motion is represented by the motion of water?
Last Answer : Transverse waves.
Description : What are some examples of wave motion?
Last Answer : Sound waves, light waves, radio waves, heat waves, water waves.
Description : What is wave motion?
Last Answer : A means of transferring energy from one place to another.
Description : How is a wave defined as it applies to wave propagation?
Last Answer : A wave is a disturbance which moves through a medium
Description : In the inverting configuration, what is the voltage (for all practical purposes) at the inverting input to the operational amplifier if the input signal is a 1-volt, peak-to-peak sine wave?
Last Answer : 0 volts.
Description : In a full-wave voltage doubler, are the capacitors connected in series or in parallel with the output load?
Last Answer : In parallel.
Description : If a half-wave rectifier is added to a half-wave voltage doubler, the resulting circuit is a voltage ___
Last Answer : Trippler.
Description : A half-wave voltage doubler is made up of how many half wave rectifiers?
Last Answer : Two.
Description : Is a full-wave rectifier output easier to filter than that of a half-wave rectifier?
Last Answer : Yes.
Description : What main advantage does a bridge rectifier have over a conventional full-wave rectifier?
Last Answer : The bridge rectifier can produce twice the voltage with the same size transformer.
Description : What is the main disadvantage of a conventional full-wave rectifier?
Last Answer : Peak voltage is half that of the half-wave rectifier.
Description : What is the average voltage (Eavg) Output of a full-wave rectifier with an output of 100 volts peak?
Last Answer : 63.7 volts.