3D153 Vol 2 Ure

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  • 1/100 Questions

    (201) Equipment used for generating, amplifying, and transmitting RF carrier is collectively called 

    • A receiver.
    • An antenna
    • A transmitter
    • A transmission line
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About This Quiz

The 3D153 Vol 2 URE quiz assesses knowledge on radio frequency communication systems, focusing on transmitter functions, receiver characteristics, and transmission line losses. It is designed for learners aiming to enhance their understanding of electronic and communication engineering principles.

3D153 Vol 2 Ure - Quiz

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  • 2. 

    (202) Which of the following CANNOT be performed by the transceiver’s computerizedcomponents and micro-circuitry? 

    • Specific equipment faults.

    • Internal equipment tests

    • Internal calibrations

    • Repair itself

    Correct Answer
    A. Repair itself
    Explanation
    The transceiver's computerized components and micro-circuitry are responsible for various functions such as specific equipment faults, internal equipment tests, and internal calibrations. However, the transceiver's computerized components and micro-circuitry cannot repair itself.

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  • 3. 

    (203) A transmission line that consists of a center conductor placed inside a rigid metal tubefunctioning as the outer tube is called a

    • Flexible coaxial cable.

    • Rigid coaxial cable.

    • Waveguide

    • Twin lead

    Correct Answer
    A. Rigid coaxial cable.
    Explanation
    A transmission line that consists of a center conductor placed inside a rigid metal tube functioning as the outer tube is called a rigid coaxial cable. This type of coaxial cable provides better protection against interference and signal loss due to its rigid structure. The outer metal tube acts as a shield, preventing external electromagnetic interference from affecting the signal transmission. The rigid coaxial cable is commonly used in applications that require high-frequency signal transmission, such as telecommunications and broadcasting.

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  • 4. 

    (203) Using figure 1–10, determine the electrical length if the frequency is changed from 150MHz to 250 MHz.

    • 8.33 meters

    • 8.33 wavelengths

    • 83.3 meters

    • 83.3 wavelengths

    Correct Answer
    A. 8.33 wavelengths
    Explanation
    The electrical length of a transmission line is determined by the number of wavelengths it takes for a signal to travel through it. In this question, the frequency is changed from 150MHz to 250MHz. Since frequency and wavelength are inversely proportional, as the frequency increases, the wavelength decreases. Therefore, the electrical length will be the same as the original length, but measured in terms of the new wavelength. So, the correct answer is 8.33 wavelengths.

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  • 5. 

    (204) Which basic field detaches from the antenna and travels through space at great distances?

    • Radiation

    • Induction

    • Gravitational

    • Electromotive

    Correct Answer
    A. Radiation
    Explanation
    Radiation is the correct answer because it refers to the process by which energy is emitted in the form of waves or particles and travels through space. In the context of the question, radiation specifically refers to electromagnetic radiation, such as radio waves, which detach from the antenna and travel through space over great distances.

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  • 6. 

    (206) The actual range of frequencies within the antenna’s bandwidth is called the

    • Wavelength

    • Operating zone

    • Frequency range

    • Bandwidth range

    Correct Answer
    A. Frequency range
    Explanation
    The actual range of frequencies within the antenna's bandwidth is referred to as the frequency range. This term encompasses the specific frequencies that the antenna is capable of transmitting or receiving signals at. It indicates the span of frequencies that the antenna is designed to operate within, allowing for effective communication within that range. The frequency range is an important consideration when selecting an antenna for a particular application, as it determines the compatibility and performance of the antenna with the desired frequency band.

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  • 7. 

    (206) The ability of an antenna to both receive and transmit equally well is known as theantenna’s

    • Bandwidth.

    • Resonance.

    • Reciprocity.

    • Effectiveness.

    Correct Answer
    A. Reciprocity.
    Explanation
    Reciprocity refers to the ability of an antenna to perform equally well in both receiving and transmitting signals. It implies that the antenna's characteristics, such as gain and radiation pattern, remain the same regardless of whether it is used for receiving or transmitting. Bandwidth refers to the range of frequencies over which an antenna can operate effectively, resonance refers to the natural frequency at which an antenna vibrates, and effectiveness is a general term that does not specifically describe the ability to receive and transmit signals equally well.

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  • 8. 

    (207) Which antenna radiates radio energy equally well in all directions?

    • Omni-directional.

    • Uni-directional.

    • Bi-directional.

    • Directional.

    Correct Answer
    A. Omni-directional.
    Explanation
    An omni-directional antenna radiates radio energy equally well in all directions. This means that it can transmit and receive signals from any direction without the need for adjusting or orienting the antenna. This type of antenna is commonly used in applications where a wide coverage area is needed, such as in broadcasting or wireless communication systems. Uni-directional, bi-directional, and directional antennas, on the other hand, have specific patterns or angles in which they transmit or receive signals, making them more suitable for targeted or specific communication purposes.

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  • 9. 

    (209) A common satellite antenna is the

    • Whip.

    • Discone.

    • Parabolic.

    • Long-wire.

    Correct Answer
    A. Parabolic.
    Explanation
    A parabolic satellite antenna is a common type of satellite antenna that is shaped like a parabola. The shape of the parabolic dish allows it to focus incoming radio waves onto a receiver, improving the signal strength and quality. This design is commonly used for satellite communication because it provides high gain and can effectively transmit and receive signals over long distances. The other options, such as whip, discone, and long-wire, are not typically used as satellite antennas.

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  • 10. 

    (209) A helical satellite antenna radiates a signal with what type of polarization?

    • Horizontal.

    • Vertical.

    • Circular.

    • Linear.

    Correct Answer
    A. Circular.
    Explanation
    A helical satellite antenna radiates a signal with circular polarization because the helical design of the antenna causes the electromagnetic waves to rotate as they are emitted. This means that the electric field vector of the signal rotates in a circular motion as it propagates, resulting in circular polarization. Circular polarization is advantageous for satellite communication as it helps to mitigate signal degradation caused by changes in the orientation of the receiving antenna.

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  • 11. 

    (212) Which environment area will increase maintenance problems with dust and sand?

    • Polar.

    • Jungle.

    • Desert.

    • Mountainous.

    Correct Answer
    A. Desert.
    Explanation
    The correct answer is Desert. Deserts are characterized by dry and arid conditions, with a lack of vegetation and high levels of dust and sand. These environmental factors can pose significant challenges for maintenance, as dust and sand can accumulate and cause damage to machinery and equipment. Additionally, the extreme temperatures and harsh conditions in deserts can also increase the wear and tear on vehicles and infrastructure, leading to increased maintenance needs.

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  • 12. 

    (212) In mountainous terrain, with a mountain between you and the distant end, which of theseantennas is more effective?

    • Whip.

    • Dipole.

    • Discone.

    • Near-vertical incidence skywave.

    Correct Answer
    A. Near-vertical incidence skywave.
    Explanation
    In mountainous terrain, with a mountain between you and the distant end, the near-vertical incidence skywave antenna is more effective. This is because the near-vertical incidence skywave antenna is designed to transmit signals at high angles, allowing them to bounce off the ionosphere and reach the desired destination. In mountainous terrain, where traditional line-of-sight antennas like the whip, dipole, and discone may be obstructed by the mountains, the near-vertical incidence skywave antenna can overcome this obstacle and provide better signal reception.

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  • 13. 

    (213) Radio waves that travel near the earth’s surface are called

    • Earth waves.

    • Global waves.

    • Ground waves.

    • Terrestrial waves.

    Correct Answer
    A. Ground waves.
    Explanation
    Radio waves that travel near the earth's surface are called ground waves. These waves are able to follow the curvature of the earth and propagate along the ground, making them suitable for communication over relatively short distances. Ground waves are commonly used for broadcasting and are able to cover large areas without the need for additional transmission equipment.

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  • 14. 

    (214) The angle at which a radio wave enters the ionosphere is known as the

    • Skip angle.

    • Critical angle.

    • Angle of entrance.

    • Angle of incidence.

    Correct Answer
    A. Angle of incidence.
    Explanation
    The angle at which a radio wave enters the ionosphere is known as the angle of incidence. This is the angle between the incident wave and the normal to the surface of the ionosphere. The angle of incidence determines how the radio wave will be refracted or reflected by the ionosphere, and it is an important factor in determining the propagation characteristics of the wave. The other options, skip angle, critical angle, and angle of entrance, do not accurately describe the angle at which a radio wave enters the ionosphere.

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  • 15. 

    (216) What U.S. government agency divides the radio frequency spectrum into different bands?

    • Federal Aviation Agency.

    • American National Standard Institute.

    • Federal Communications Commission.

    • Institute of Electrical & Electronics Engineers, Inc.

    Correct Answer
    A. Federal Communications Commission.
    Explanation
    The Federal Communications Commission (FCC) is the correct answer because it is the U.S. government agency responsible for regulating and managing the radio frequency spectrum. The FCC divides the spectrum into different bands to ensure efficient and effective use of the limited radio frequency resources. This division allows for the allocation of specific frequencies to different users, such as broadcasters, wireless communication providers, and government agencies, to prevent interference and promote smooth communication. The FCC also sets rules and standards for the use of these frequency bands to ensure fair and equitable access for all users.

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  • 16. 

    (219) Super high/extremely high frequency range is limited to

    • Scattering.

    • Line-of-sight.

    • Earth’s conductivity.

    • Atmospheric absorption.

    Correct Answer
    A. Line-of-sight.
    Explanation
    The correct answer is line-of-sight. In the super high/extremely high frequency range, the signals travel in a straight line and do not bend around obstacles. This means that for effective communication, there must be a clear line-of-sight between the transmitter and receiver. Any obstacles such as buildings, mountains, or trees can block or weaken the signal, resulting in communication issues. Therefore, the range of super high/extremely high frequency signals is limited to line-of-sight transmission.

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  • 17. 

    (220) The refractive index of air depends on moisture,

    • Atmospheric pressure, and temperature.

    • Atmospheric pressure, and frequency.

    • Receive signal level, and temperature.

    • Receive signal level, and frequency.

    Correct Answer
    A. Atmospheric pressure, and temperature.
    Explanation
    The refractive index of air is influenced by atmospheric pressure and temperature. Changes in atmospheric pressure can affect the density of air, which in turn affects the speed of light passing through it. Similarly, changes in temperature can also alter the density of air, leading to changes in the refractive index. Moisture and frequency are not mentioned as factors that affect the refractive index of air in the given information.

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  • 18. 

    (222) What is the first step in electronic warfare application?

    • Denial.

    • Detection.

    • Deception.

    • Disruption.

    Correct Answer
    A. Detection.
    Explanation
    The first step in electronic warfare application is detection. This involves identifying and locating the presence of enemy electronic signals or activities. Detection is crucial as it provides valuable information about the enemy's electronic capabilities and intentions, allowing for effective countermeasures to be developed and implemented. Without detection, it would be difficult to effectively engage in electronic warfare and gain an advantage over the enemy.

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  • 19. 

    (225) The common name for the method of changing the encryption keys over the radio channelin a two-way radio system is called

    • Over-the-air-rekeying.

    • Asymmetric.

    • Symmetric.

    • Off-line.

    Correct Answer
    A. Over-the-air-rekeying.
    Explanation
    Over-the-air rekeying refers to the method of changing encryption keys over a radio channel in a two-way radio system. This process allows for secure and efficient communication by regularly updating the encryption keys used to protect the transmitted data. It is an essential security measure to prevent unauthorized access and maintain the confidentiality of the communication.

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  • 20. 

    (233) Which conventional land mobile radio device serves as the hub of a net?

    • Portable.

    • Mobile.

    • Repeater.

    • Base station.

    Correct Answer
    A. Base station.
    Explanation
    A base station is a conventional land mobile radio device that serves as the hub of a net. It is a fixed station that communicates with portable and mobile devices within its coverage area. The base station typically has a higher power output and a larger antenna compared to portable and mobile devices, allowing it to provide wider coverage and better communication quality. It is responsible for coordinating and controlling the communication within the network, making it the central hub of the net.

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  • 21. 

    (237) In high frequency communications, your station’s self address is the address

    • The user programmed into your system.

    • It shares with other members.

    • Of an unprogrammed station.

    • Of other stations in the net.

    Correct Answer
    A. The user programmed into your system.
    Explanation
    In high frequency communications, your station's self address refers to the address that the user has programmed into the system. This address is specific to your station and is not shared with other members. It is not the address of an unprogrammed station or the address of other stations in the network.

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  • 22. 

    (240) What assembly on the AN/PRC–150 contains the keyboard and the liquid crystal display(LCD) that makes up the radio’s man-machine interface?

    • Chassis assembly.

    • Rear panel assembly.

    • Keyboard display unit.

    • Upper chassis assembly.

    Correct Answer
    A. Keyboard display unit.
    Explanation
    The keyboard display unit is the assembly on the AN/PRC-150 that contains the keyboard and the liquid crystal display (LCD) that make up the radio's man-machine interface. This unit allows the user to input commands and view information on the radio's display screen. The other options, such as chassis assembly, rear panel assembly, and upper chassis assembly, do not specifically mention the keyboard and LCD components.

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  • 23. 

    (201) What basic receiver function involves having the transmitted electromagnetic wave passthrough the receive antenna in such a manner as to induce a voltage in the antenna? 

    • Reproduction

    • Reception

    • Detection

    • Selection

    Correct Answer
    A. Reception
    Explanation
    Reception is the correct answer because it involves the process of having the transmitted electromagnetic wave pass through the receive antenna and inducing a voltage in the antenna. This is the fundamental function of a receiver, where it captures and converts the electromagnetic signals into usable electrical signals for further processing. The other options, reproduction, detection, and selection, do not accurately describe this specific process of inducing a voltage in the receive antenna.

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  • 24. 

    (201) The ability of a receiver to reproduce the signal of a very weak station is the characteristic ofthe receiver’s

    • Fidelity

    • Capacity

    • Sensitivity

    • Selectivity

    Correct Answer
    A. Sensitivity
    Explanation
    Sensitivity refers to the ability of a receiver to reproduce the signal of a very weak station. A receiver with high sensitivity can pick up and amplify weak signals, allowing the user to receive stations that may be far away or have a low power output. Fidelity refers to the accuracy with which the receiver reproduces the original signal, capacity refers to the amount of information the receiver can handle, and selectivity refers to the ability of the receiver to separate and filter out unwanted signals.

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  • 25. 

    (201) The ability to reproduce the input signal accurately is the characteristics of the receiver’s

    • Fidelity

    • Capacity

    • Sensitivity

    • Fidelity

    Correct Answer
    A. Fidelity
    Explanation
    The ability to reproduce the input signal accurately is known as fidelity. Fidelity refers to the accuracy and faithfulness with which a receiver can reproduce the original signal without any distortion or loss of information. It is an important characteristic of a receiver as it ensures that the received signal is as close to the original as possible, allowing for clear and accurate communication.

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  • 26. 

    (203) Leakage loss in a transmission line can be minimized by using a

    • Thinner conductor

    • Thicker conductor

    • Very low-resistance dielectric

    • Very high-resistance dielectric

    Correct Answer
    A. Very high-resistance dielectric
    Explanation
    Using a very high-resistance dielectric can minimize leakage loss in a transmission line. Leakage loss refers to the energy that is lost as heat due to the leakage of electric current from the conductor to the surrounding environment. By using a high-resistance dielectric, the amount of current leakage is reduced, resulting in lower energy loss. This is because the high-resistance dielectric acts as an insulator, preventing the flow of current through it and minimizing the leakage.

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  • 27. 

    (203) Which statement concerning waveguides is FALSE?

    • Very slight damage to the external surface of a waveguide can cause arcing.

    • Their conductive material construction is easily dented.

    • Effectiveness of waveguides is hindered by moisture.

    • Waveguides can be destroyed by corrosion.

    Correct Answer
    A. Very slight damage to the external surface of a waveguide can cause arcing.
    Explanation
    Waveguides are designed to handle high power levels, and therefore very slight damage to the external surface of a waveguide is unlikely to cause arcing. Arcing is more likely to occur when there is significant damage or a large discontinuity in the waveguide structure.

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  • 28. 

    (205) If the electric field component travels in a plane perpendicular to the Earth’s surface, theradio wave is considered to be polarized

    • Magnetically

    • Horizontally.

    • Circularly.

    • Vertically

    Correct Answer
    A. Vertically
    Explanation
    If the electric field component of a radio wave travels in a plane perpendicular to the Earth's surface, the wave is considered to be vertically polarized. This means that the electric field oscillates in a vertical direction as the wave propagates.

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  • 29. 

    (207) Which antenna type is usually used on long-range, point-to-point communication where theconcentrated radio energy is needed for circuit reliability?

    • Omni-directional.

    • Uni-directional.

    • Bi-directional.

    • Circular.

    Correct Answer
    A. Uni-directional.
    Explanation
    Uni-directional antennas are usually used on long-range, point-to-point communication where concentrated radio energy is needed for circuit reliability. These antennas focus the radio energy in one direction, allowing for a stronger and more reliable signal over long distances. Omni-directional antennas radiate the signal in all directions, making them less suitable for long-range point-to-point communication. Bi-directional antennas transmit and receive signals in two opposite directions, while circular antennas are designed to radiate the signal in a circular pattern, which may not be ideal for long-range point-to-point communication.

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  • 30. 

    (209) What is one of the simplest and most functional antennas in use?

    • Quarter-wave vertical.

    • Half-wave dipole.

    • Inverted-V.

    • GRA–4.

    Correct Answer
    A. Half-wave dipole.
    Explanation
    A half-wave dipole is one of the simplest and most functional antennas in use. It consists of two conductive elements, each measuring half the wavelength of the signal being transmitted or received. The dipole antenna is easy to construct and provides a balanced radiation pattern, making it effective for both transmitting and receiving signals. It is commonly used in radio communication and is known for its efficiency and versatility.

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  • 31. 

    (209) What is the minimum length for a long-wire antenna?

    • One-quarter wavelength.

    • One-half wavelength.

    • One wavelength.

    • Two wavelengths.

    Correct Answer
    A. One-half wavelength.
    Explanation
    A long-wire antenna is a type of antenna that is used for transmitting and receiving radio signals. The length of the antenna is crucial for its performance. The minimum length for a long-wire antenna is one-half wavelength. This length allows for the antenna to efficiently radiate and receive signals. A shorter antenna would not be able to effectively capture and transmit the radio waves, while a longer antenna would introduce unnecessary complexity and could lead to interference. Therefore, a one-half wavelength is the optimal length for a long-wire antenna.

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  • 32. 

    (210) Which type of airborne antenna can be designed into any part of an aerospace vehicle’ssurface, so that it does not upset its aerodynamic properties?

    • Fixed blade.

    • Conformal.

    • Probe tip.

    • Whip.

    Correct Answer
    A. Conformal.
    Explanation
    A conformal antenna is designed to be integrated seamlessly into the surface of an aerospace vehicle without affecting its aerodynamic properties. This means that the antenna can be shaped and positioned in a way that it blends in with the vehicle's structure, minimizing any disruption to its airflow. This type of antenna is ideal for applications where maintaining the vehicle's aerodynamic performance is crucial, such as in aircraft or missiles.

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  • 33. 

    (212) In siting a radio station, which foliage would have more of an adverse effect on radio wavepropagation?

    • Broadleaf trees.

    • Evergreen trees.

    • Swamp grass.

    • Sagebrush.

    Correct Answer
    A. Broadleaf trees.
    Explanation
    Broadleaf trees would have more of an adverse effect on radio wave propagation compared to evergreen trees, swamp grass, and sagebrush. This is because broadleaf trees have denser foliage and a higher water content, which can absorb and scatter radio waves more effectively. This absorption and scattering can result in a weaker signal and reduced coverage area for the radio station. Evergreen trees, swamp grass, and sagebrush have less dense foliage and lower water content, leading to a lesser impact on radio wave propagation.

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  • 34. 

    212) Which environment would be considered the most challenging for an RF transmissionsystems technician to establish and operate a radio station from?

    • Amazon.

    • North Pole.

    • Sahara Desert.

    • Sierra Nevada Mountains.

    Correct Answer
    A. Amazon.
    Explanation
    The Amazon would be considered the most challenging environment for an RF transmission systems technician to establish and operate a radio station from. The dense vegetation and vast expanse of the rainforest would make it difficult to find suitable locations for tower placement and antenna installation. Additionally, the high humidity and constant rainfall in the Amazon could cause signal interference and equipment damage. The remote and inaccessible nature of the rainforest would also pose logistical challenges for transporting equipment and maintaining the radio station.

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  • 35. 

    (214) In HF communications, the lowest frequency that arrives at the distant receiver on 90percent of the undisturbed days of the month is called the

    • Maximum usable frequency.

    • Lowest usable frequency.

    • Operating frequency.

    • Critical frequency.

    Correct Answer
    A. Lowest usable frequency.
    Explanation
    The lowest usable frequency in HF communications refers to the frequency that consistently arrives at the distant receiver on 90% of undisturbed days in a month. This frequency is the minimum frequency that can reliably transmit signals over long distances without being affected by disturbances or interference. It is important to determine the lowest usable frequency to ensure effective communication in HF systems.

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  • 36. 

    (215) Scientist call the ionosphere an extension of thea. thermosphere.

    • Thermosphere.

    • Stratosphere.

    • Mesosphere.

    • Exosphere.

    Correct Answer
    A. Thermosphere.
    Explanation
    The ionosphere is a region of the Earth's atmosphere that contains a high concentration of ions and free electrons. It is located in the upper part of the atmosphere, above the mesosphere and below the exosphere. The thermosphere is the layer of the atmosphere that lies above the mesosphere and is characterized by high temperatures. Since the ionosphere is located within the thermosphere, scientists consider it to be an extension of the thermosphere.

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  • 37. 

    (215) What occurs when high-energy ultraviolet light waves from the sun enter the ionosphericregion of the atmosphere and strike the gas atoms?

    • Ionization.

    • Modulation.

    • Conductivity.

    • Recombination.

    Correct Answer
    A. Ionization.
    Explanation
    When high-energy ultraviolet light waves from the sun enter the ionospheric region of the atmosphere and strike the gas atoms, ionization occurs. Ionization is the process in which an atom or molecule gains or loses electrons, resulting in the formation of charged particles called ions. In this case, the high-energy ultraviolet light waves provide enough energy to remove electrons from the gas atoms, creating ions.

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  • 38. 

    (215) Sunspots are disturbances

    • In the sun’s atmosphere.

    • On the sun’s surface.

    • In the ionosphere.

    • Beneath the sun’s surface.

    Correct Answer
    A. On the sun’s surface.
    Explanation
    Sunspots are dark areas on the sun's surface that appear cooler than the surrounding areas. These spots are caused by magnetic activity and are associated with intense magnetic fields. They can vary in size and shape and can last for days or even months. Sunspots are visible on the sun's surface and can be observed using telescopes or other solar viewing instruments. Therefore, the correct answer is "on the sun's surface."

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  • 39. 

    (223) Name the process of unscrambling the encrypted information so that it is intelligible.

    • Decryption.

    • Encryption.

    • Cryptography.

    • Cryptanalysis.

    Correct Answer
    A. Decryption.
    Explanation
    Decryption is the process of unscrambling encrypted information to make it intelligible. It involves using a key or algorithm to reverse the encryption process and convert the encrypted data back into its original form. Cryptography refers to the practice of securing communication through encryption, while cryptanalysis is the study of analyzing and breaking encryption systems. Therefore, decryption is the correct answer as it specifically refers to the process of unscrambling encrypted information.

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  • 40. 

    (224) How many selectable traffic key slots does the KG–84A have?

    • 1.

    • 2.

    • 4.

    • 8.

    Correct Answer
    A. 4.
    Explanation
    The KG-84A has 4 selectable traffic key slots. This means that it can store and use up to 4 different encryption keys for secure communication. Each key slot allows for a different key to be loaded and used, providing flexibility and versatility in encryption operations.

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  • 41. 

    (203) Resistance of the conductor material in a transmission line leads to which type of loss?

    • Copper

    • Radiation

    • Inductive

    • Skin-effect

    Correct Answer
    A. Copper
    Explanation
    The resistance of the conductor material in a transmission line leads to copper loss. As current flows through the conductor, it encounters resistance, which results in the conversion of electrical energy into heat. This heat generation causes power loss in the form of copper loss. Copper loss is a common type of power loss in transmission lines and is influenced by factors such as the length and cross-sectional area of the conductor.

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  • 42. 

    (203) A nonresonant transmission line is a line

    • Having reflected waves.

    • Having no reflected waves.

    • With maximum voltage across its open termination.

    • With maximum voltage across its shorted termination.

    Correct Answer
    A. Having no reflected waves.
    Explanation
    A nonresonant transmission line is a line that does not have any reflected waves. This means that all of the energy that is sent down the line is absorbed by the load at the end of the line, and there is no energy bouncing back towards the source. This is desirable in many applications as it allows for efficient transmission of signals without any loss or distortion caused by reflected waves.

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  • 43. 

    (203) If a transmission line is terminated in an open, what will likely result? 

    • Signal loss would be negligible.

    • There would be significant signal loss.

    • Current would be at maximum at the termination.

    • Voltage would be at minimum at the termination.

    Correct Answer
    A. There would be significant signal loss.
    Explanation
    When a transmission line is terminated in an open, there will be a mismatch between the impedance of the line and the termination impedance. This mismatch will cause a portion of the signal to be reflected back towards the source, resulting in signal loss. Therefore, there would be significant signal loss in this scenario.

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  • 44. 

    (204) The concept that alternating current changes in magnitude and reverses its direction duringeach cycle is

    • An unproven hypothesis

    • The definition of propagation.

    • What makes radio transmission possible.

    • What led to the discovery of direct current.

    Correct Answer
    A. What makes radio transmission possible.
    Explanation
    The concept that alternating current changes in magnitude and reverses its direction during each cycle is what makes radio transmission possible. Radio waves are generated by rapidly changing the direction and magnitude of the electric current, which creates oscillating electromagnetic fields. These oscillating fields can then be detected by antennas and converted back into electrical signals, allowing for the transmission and reception of radio signals. Therefore, the concept of alternating current is essential for the functioning of radio transmission.

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  • 45. 

    (204) At what point do magnetic fields around a wire no longer have time to collapse completelybetween alternations?

    • 60 cycles per second (cps).

    • 120 cps

    • 10,000 cps

    • 15,000 cps

    Correct Answer
    A. 10,000 cps
    Explanation
    The correct answer is 10,000 cps. At this frequency, the alternations of the magnetic fields around a wire are occurring so rapidly that there is not enough time for the fields to collapse completely between each alternation. This means that the magnetic fields remain relatively constant and do not have enough time to fully collapse before they are reestablished in the opposite direction.

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  • 46. 

    (206) What does the overall effectiveness of an entire transmitting and receiving system dependlargely upon?

    • Impedance matching.

    • Antenna distance.

    • Antenna properties.

    • Line characteristics.

    Correct Answer
    A. Impedance matching.
    Explanation
    The overall effectiveness of an entire transmitting and receiving system largely depends on impedance matching. Impedance matching ensures that the impedance of the source (transmitter) and the load (antenna) are matched, allowing for maximum power transfer and minimizing signal reflections. Antenna distance, antenna properties, and line characteristics can also impact the system's performance, but impedance matching is the most crucial factor for optimal functioning.

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  • 47. 

    (211) In HF communications, by replacing the vertical antenna with a dipole antenna that’s aquarter wavelength off the ground, what are you able to get from your antenna transmission?

    • Higher take-off angle.

    • Increase efficiency.

    • Better reciprocity.

    • Twice the gain.

    Correct Answer
    A. Higher take-off angle.
    Explanation
    By replacing the vertical antenna with a dipole antenna that's a quarter wavelength off the ground, you are able to achieve a higher take-off angle in your antenna transmission. This means that the signal will be radiated at a steeper angle, allowing it to reach higher altitudes and potentially cover a larger area. This can be beneficial in certain scenarios, such as when trying to communicate with stations located at higher elevations or over long distances.

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  • 48. 

    (214) Radio waves that angled too low are

    • Absorbed.

    • Refracted.

    • Returned to earth.

    • Passed into space.

    Correct Answer
    A. Absorbed.
    Explanation
    Radio waves that are angled too low are absorbed. When radio waves travel through the atmosphere, they can be affected by various factors such as the angle at which they are transmitted. If the angle is too low, the radio waves are more likely to interact with and be absorbed by objects in the atmosphere, such as buildings or trees. This absorption can result in a weaker signal or complete loss of the radio waves. Therefore, radio waves that are angled too low are absorbed rather than being refracted, returned to earth, or passed into space.

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  • 49. 

    (215) How many regions make up the atmosphere?

    • 2.

    • 3.

    • 4.

    • 5.

    Correct Answer
    A. 5.
    Explanation
    The atmosphere is divided into five main regions based on their altitude: troposphere, stratosphere, mesosphere, thermosphere, and exosphere. Each region has distinct characteristics and plays a specific role in the Earth's climate system.

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Quiz Review Timeline (Updated): Mar 17, 2023 +

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  • Current Version
  • Mar 17, 2023
    Quiz Edited by
    ProProfs Editorial Team
  • May 10, 2016
    Quiz Created by
    Powers.zackrey
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