CDC 2e151 Satellite, Wideband, And Telemetry Systems Journeyman Volume 1
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On what kind of clock system is coordinated universal time based?
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12-hout.
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24-hour.
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Daylight saving.
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Amplitude modulation and pulse modulation.
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CDC 2E151 Satellite, Wideband, and Telemetry Systems Journeyman Volume 1. This test consists of UREs and Self-Test Questions from volume 1, set 2.
Quiz Preview
- 2.
How can you normally eliminate electromagnetic interference noise bursts caused by sodium and mercury vapor lights that have stopped working while the power is still applied?
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Change the bulb
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Ground out the light fixture
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Install a noise reject filter on the light
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Install a noise reject filter on the receiver
Correct Answer
A. Change the bulbExplanation
When sodium and mercury vapor lights stop working while the power is still applied, they can cause electromagnetic interference noise bursts. The best way to eliminate this interference is by changing the bulb. By replacing the faulty bulb with a new one, the electromagnetic interference caused by the malfunctioning light will be resolved.Rate this question:
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- 3.
At what level does the Air Force want electromagnetic interference problems resolved?
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Affected unit
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Affected major command
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Electromagnetic environmental effects office
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Spectrum interference resolution office
Correct Answer
A. Affected unitExplanation
The Air Force wants electromagnetic interference problems resolved at the level of the affected unit. This means that the responsibility for addressing and resolving these problems lies with the specific unit that is experiencing the interference. They are expected to take appropriate measures to mitigate the interference and ensure that their operations are not affected. This approach allows for a more localized and efficient resolution of the issue, as the unit directly impacted by the interference is best positioned to understand and address the problem.Rate this question:
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- 4.
In fiber optics, which component of the fiber is the optical transmission path?
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Cladding.
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Coating.
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Buffer.
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Core.
Correct Answer
A. Core.Explanation
The core of a fiber optic cable is the central region through which light is transmitted. It is made of a highly transparent material with a high refractive index, allowing the light to propagate through it by total internal reflection. The cladding, coating, and buffer layers surround and protect the core, but they do not serve as the primary optical transmission path. Therefore, the core is the correct answer.Rate this question:
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- 5.
What is multiplexing?
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Transmitting one signal over multiple transmission paths.
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Transmitting one signal multiple times over a single transmission path.
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Combining multiple signals for transmission over a single transmission path.
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Combining multiple signals for transmission over separate, individual transmission paths.
Correct Answer
A. Combining multiple signals for transmission over a single transmission path.Explanation
Multiplexing refers to the process of combining multiple signals into a single transmission path. This allows for more efficient use of the available bandwidth and resources. By combining multiple signals, it is possible to transmit more information simultaneously over a single transmission path, increasing the overall capacity and efficiency of the system. This is commonly used in telecommunications and networking to optimize the use of limited resources and improve data transmission efficiency.Rate this question:
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- 6.
What signals originating from the satellite do we use to acquire and track the satellite?
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Beacon.
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Ephemeris.
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Telemetry.
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Communication.
Correct Answer
A. Beacon.Explanation
The signals originating from the satellite that we use to acquire and track the satellite are called beacons. Beacons are specific signals transmitted by the satellite that serve as a reference point for tracking and locating the satellite. By receiving and analyzing the beacon signals, we can determine the satellite's position, velocity, and other important parameters necessary for tracking and acquiring the satellite.Rate this question:
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- 7.
Solar time is based on
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Atomic clock oscillations.
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Apparent constellation movement.
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The moon's rotation about the sun.
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The apparent motion of the sun in the sky.
Correct Answer
A. The apparent motion of the sun in the sky.Explanation
Solar time is based on the apparent motion of the sun in the sky. It is determined by the position of the sun relative to an observer's location on Earth. As the Earth rotates on its axis, the sun appears to move across the sky, causing shadows to shift and indicating the passage of time. This natural movement of the sun serves as the basis for solar time, which is used to set clocks and determine local time in different regions.Rate this question:
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- 8.
Uploading satellite control data, tracking ballistic missiles, and predicting satellite tracking coordinates are examples of missions where all parties involved must have
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Offset timing.
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Synchronized timing.
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Identical time code formats.
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Different time code formats.
Correct Answer
A. Synchronized timing.Explanation
In order to successfully upload satellite control data, track ballistic missiles, and predict satellite tracking coordinates, all parties involved must have synchronized timing. This means that they need to have their clocks set to the same time and be able to coordinate their actions and communications based on this synchronized timing. Having synchronized timing ensures that all parties are operating on the same schedule and can effectively carry out these missions.Rate this question:
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- 9.
Broadband transmitter noise can often be eliminated by
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Using a band pass filter.
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Using a band reject filter.
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Increasing output power.
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Decreasing output power.
Correct Answer
A. Using a band pass filter.Explanation
Broadband transmitter noise refers to unwanted signals that are spread across a wide range of frequencies. To eliminate this noise, a band pass filter can be used. A band pass filter allows only a specific range of frequencies to pass through while attenuating frequencies outside of that range. By using a band pass filter, the desired signal within the specific frequency range can be transmitted effectively while blocking out the unwanted noise. This helps in improving the overall signal quality and reducing interference.Rate this question:
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- 10.
Troposcatter losses are usually worse during
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Winter nights.
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Winter days.
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Summer nights.
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Summer days.
Correct Answer
A. Winter nights.Explanation
Troposcatter losses refer to the attenuation of radio signals due to scattering in the troposphere. During winter nights, the atmosphere is typically more stable, which leads to stronger temperature inversions. These inversions cause the radio signals to be trapped closer to the ground, resulting in increased scattering and higher losses. Therefore, troposcatter losses are usually worse during winter nights.Rate this question:
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- 11.
When computing satellite look angles, ground distance on the earth’s surface is expressed in
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Degrees.
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Seconds.
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Minutes.
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Nautical miles.
Correct Answer
A. Degrees.Explanation
When computing satellite look angles, ground distance on the earth's surface is expressed in degrees. This is because look angles are used to determine the direction in which a satellite needs to be pointed from a specific location on Earth. Ground distance is measured in degrees of latitude and longitude, which are the standard units for expressing locations on the Earth's surface. Degrees provide a precise and standardized way to calculate the angle and direction of the satellite in relation to the ground.Rate this question:
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- 12.
When any frequency source regardless of its accuracy or stability is used as the sole calibration reference for other frequency sources, what kind of standard is it?
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First generation.
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Secondary.
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Primary.
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Class 1.
Correct Answer
A. Primary.Explanation
When any frequency source, regardless of its accuracy or stability, is used as the sole calibration reference for other frequency sources, it is considered a primary standard. A primary standard is the highest level of calibration reference and is used to establish the accuracy and stability of other frequency sources. It serves as the ultimate reference for calibration and is typically traceable to national or international standards.Rate this question:
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- 13.
Which type of airborne antenna can be designed into any part of an aerospace vehicle’s surface, so that it does not upset its aerodynamic properties?
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Fixed blade.
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Conformal.
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Probe tip.
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Whip.
Correct Answer
A. Conformal.Explanation
A conformal airborne antenna can be designed into any part of an aerospace vehicle's surface, such as the fuselage or wings, without affecting its aerodynamic properties. Unlike other types of antennas like fixed blade or whip antennas, which protrude from the surface and can cause drag, a conformal antenna is integrated seamlessly into the vehicle's shape. This allows for improved aerodynamic performance while still maintaining the functionality of the antenna.Rate this question:
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- 14.
An atomic time scale could be based on the frequency of which type of oscillator?
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Pendulum.
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Cyrstal.
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Quartz.
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Cesium.
Correct Answer
A. Cesium.Explanation
An atomic time scale could be based on the frequency of a cesium oscillator. Cesium atomic clocks work by measuring the vibrations of cesium atoms, which have a very stable and consistent frequency. This frequency is used as a reference to accurately measure time. Cesium atomic clocks are widely used in scientific research, telecommunications, and other applications where precise timekeeping is essential.Rate this question:
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- 15.
The refractive index of air depends on moisture,
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Atmospheric pressure, and temperature.
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Atmospheric pressure, and frequency.
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Receive signal level, and temperature.
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Receive signal level, and frequency.
Correct Answer
A. Atmospheric pressure, and temperature.Explanation
The refractive index of air is influenced by two factors: atmospheric pressure and temperature. Atmospheric pressure affects the density of air, which in turn affects the speed of light as it passes through the air. As the pressure increases, the refractive index also increases. Temperature, on the other hand, affects the speed of molecules in the air, which can cause variations in the refractive index. Therefore, both atmospheric pressure and temperature play a role in determining the refractive index of air.Rate this question:
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- 16.
To determine the number of hours coordinated universal time differs from your local time, you must determine the number of time zones between your location and the location of the zero
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Median.
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Latitude.
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Parallel.
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Meridian.
Correct Answer
A. Meridian.Explanation
The correct answer is meridian. To determine the number of hours coordinated universal time (UTC) differs from your local time, you need to consider the number of time zones between your location and the location of the zero meridian. The zero meridian, also known as the Prime Meridian, is the line of longitude that passes through Greenwich, London, and serves as the reference point for measuring time zones. By calculating the time difference between your location and the zero meridian, you can determine the number of hours UTC differs from your local time.Rate this question:
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- 17.
What type of exterior system electromagnetic pulse coupling includes imperfectly sealed personnel access doors and equipment hatches, and improper installation of penetrating conductor protection?
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Shield
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Ground system
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Intrastic conductor
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Electronic enclosure
Correct Answer
A. ShieldExplanation
The correct answer is "Shield". In an exterior system, electromagnetic pulse coupling can occur through imperfectly sealed personnel access doors and equipment hatches, as well as improper installation of penetrating conductor protection. A shield is designed to provide protection against electromagnetic interference by creating a barrier between the external environment and the sensitive electronic components inside. It prevents the coupling of electromagnetic pulses into the system by blocking or redirecting them.Rate this question:
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- 18.
Up to how many active talkers can be on one general-purpose interface bus simultaneously?
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1
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2
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5
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7
Correct Answer
A. 1Explanation
The correct answer is 1 because a general-purpose interface bus can only support one active talker at a time. This means that only one device can transmit data on the bus while others listen. Having multiple active talkers simultaneously can lead to data collisions and communication errors. Therefore, the maximum number of active talkers on a general-purpose interface bus is limited to one.Rate this question:
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- 19.
Which general-purpose interference bus lines ensure data transfer integrity?
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Data.
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Ground.
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Handshake.
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Management.
Correct Answer
A. Handshake.Explanation
The general-purpose interference bus lines that ensure data transfer integrity are handshake lines. Handshake lines are used to establish communication between devices and ensure that data is transferred accurately and without errors. These lines allow devices to exchange control signals to indicate when they are ready to send or receive data, ensuring that the data transfer occurs smoothly and without interference.Rate this question:
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- 20.
In which region of the atmosphere does all weather occur?
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Troposphere.
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Stratosphere.
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Ionosphere.
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Mesosphere.
Correct Answer
A. Troposphere.Explanation
The correct answer is Troposphere. The troposphere is the lowest layer of the Earth's atmosphere where weather occurs. It is the layer closest to the Earth's surface and extends from the surface up to about 8-15 kilometers. In this layer, temperature decreases with altitude and most of the Earth's weather phenomena, such as clouds, precipitation, and storms, take place. The other options, stratosphere, ionosphere, and mesosphere, are higher layers of the atmosphere where weather phenomena are not as prominent as in the troposphere.Rate this question:
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- 21.
What do you do when you are reasonably sure electromagnetic interference exists?
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Request engineering assistance.
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Contact the base frequency manager.
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Systematically gather data for analysis.
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Contact the Spectrum Interference Resolution office.
Correct Answer
A. Systematically gather data for analysis.Explanation
When you are reasonably sure electromagnetic interference exists, the best course of action is to systematically gather data for analysis. This involves collecting relevant information and conducting a thorough investigation to identify the source and extent of the interference. By systematically gathering data, you can analyze the problem more effectively and make informed decisions on how to mitigate or resolve the interference. This approach allows for a more comprehensive understanding of the issue and increases the chances of finding a suitable solution.Rate this question:
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- 22.
What determines the size of a waveguide?
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Cutoff frequency.
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Operating frequency.
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Amount of power transmitted.
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Minimum frequency propagated.
Correct Answer
A. Operating frequency.Explanation
The size of a waveguide is determined by the operating frequency. The operating frequency of a waveguide refers to the range of frequencies at which it can effectively transmit electromagnetic waves. Different frequencies require different physical dimensions for the waveguide to function optimally. Therefore, the size of the waveguide is directly related to the operating frequency it is designed to accommodate.Rate this question:
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- 23.
What type of light is emitted from a laser?
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Incoherent.
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Coherent.
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Ordinary.
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Invisible.
Correct Answer
A. Coherent.Explanation
A laser emits coherent light. Coherent light is light that has a fixed phase relationship between its waves, meaning that all the waves are aligned and have the same frequency and wavelength. This results in a concentrated, narrow beam of light that can travel long distances without spreading out or losing intensity. In contrast, incoherent light consists of waves with random phases and directions, while ordinary light is a combination of different wavelengths and directions. Invisible light refers to wavelengths that are outside the visible spectrum and cannot be seen by the human eye.Rate this question:
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- 24.
Laser power coupling is measured in the
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Megawatt range.
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Kilowatt range.
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Milliwatt range.
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Microwatt range.
Correct Answer
A. Milliwatt range.Explanation
The correct answer is milliwatt range. Laser power coupling refers to the process of transferring power from an external source into a laser system. The power coupling is measured in milliwatts, which is a unit of power equal to one thousandth of a watt. This suggests that the power being transferred is relatively low, indicating that the laser system being used operates at a milliwatt power range.Rate this question:
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- 25.
What is the inclination angle of a polar orbit?
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0°
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45°
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90°
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180°
Correct Answer
A. 90°Explanation
The inclination angle of a polar orbit is 90°. A polar orbit is an orbit that passes over or near the Earth's poles, and it is inclined at 90° to the equator. This means that the satellite or spacecraft in a polar orbit will pass over or near the North and South poles on each orbit. The inclination angle determines the path of the orbit and the coverage of the satellite, and a 90° inclination means that the orbit is perpendicular to the equator.Rate this question:
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- 26.
What two factors cause a quartz oscillator’s resonant frequency to drift?
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Humidity and aging.
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Temperature and aging.
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Humidity and operating frequency.
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Temperature and operating frequency.
Correct Answer
A. Temperature and aging.Explanation
The resonant frequency of a quartz oscillator can drift due to two factors: temperature and aging. Temperature changes can cause the quartz crystal to expand or contract, affecting its resonant frequency. Aging refers to the gradual degradation of the quartz crystal over time, which can also cause the resonant frequency to drift. Humidity and operating frequency are not directly related to the drift of a quartz oscillator's resonant frequency.Rate this question:
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- 27.
Aircraft antennas are housed
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Inside nonconductive radomes mounted outside or flush with the fuselage.
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Inside conductive radomes mounted outside or flush with the fuselage.
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Outside nonconductive radomes mounted outside the fuselage.
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Inside conductive radomes mounted flush with the fuselage.
Correct Answer
A. Inside nonconductive radomes mounted outside or flush with the fuselage.Explanation
Aircraft antennas are housed inside nonconductive radomes to protect them from the elements and to minimize interference with the aircraft's structure. These radomes are mounted outside or flush with the fuselage to ensure that the antennas have a clear line of sight for optimal signal reception and transmission. Using nonconductive materials for the radomes helps to prevent electrical interference and ensures that the antennas can operate effectively.Rate this question:
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- 28.
What determines an antenna’s location and orientation on the aircraft?
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Antennas always require a 360° radiating pattern.
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The type of aircraft propulsion and power system.
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Antennas are always mounted on top of the fuselage.
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Optimizing the antenna’s radiating pattern for its application.
Correct Answer
A. Optimizing the antenna’s radiating pattern for its application.Explanation
The correct answer is "Optimizing the antenna’s radiating pattern for its application." This answer explains that the location and orientation of an antenna on an aircraft are determined by the need to optimize its radiating pattern for its specific purpose or application. This suggests that the positioning of the antenna is based on factors such as the desired coverage area, signal strength, and interference avoidance, rather than being determined by the type of aircraft propulsion or power system, or a requirement for a 360° radiating pattern.Rate this question:
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- 29.
Signal loss caused by temperature inversions in the atmosphere is called
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The multi-path effect.
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Slow fading.
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Fast fading.
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Ducting.
Correct Answer
A. Ducting.Explanation
Ducting refers to the phenomenon of signal loss caused by temperature inversions in the atmosphere. During temperature inversions, the air near the ground is cooler than the air above it, which creates a layer of dense air that acts as a barrier for radio waves. This barrier causes the signals to be trapped and travel along the Earth's surface, resulting in signal loss. This effect is known as ducting, and it is a common occurrence in certain atmospheric conditions.Rate this question:
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- 30.
The operation of the atomic clock is based on the phenomenon that
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Crystals resonate when an electric charge is applied.
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Atoms release energy at a particular resonant frequency.
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Atoms are sensitive to temperature and directional effects.
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When atoms are split they produce predictable nuclear reactions.
Correct Answer
A. Atoms release energy at a particular resonant frequency.Explanation
The correct answer is "atoms release energy at a particular resonant frequency." This explanation is based on the principle of atomic clocks, which rely on the vibrations of atoms to measure time accurately. When atoms absorb energy, they move to a higher energy state. As they return to their original state, they release energy in the form of electromagnetic radiation at a specific frequency. By measuring this resonant frequency, atomic clocks can maintain precise and consistent timekeeping.Rate this question:
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- 31.
A system-generated electromagnetic pulse is a problem for satellites and reentry vehicles that are
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Susceptible to the wideband frequency phenomenon.
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Directly exposed to nuclear radiations from a high-altitude burst.
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Affected by the azimuth magnetic fields and time-varying air conductivity.
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Influenced by the signal fading or waveform distortion caused by the structured plasma field.
Correct Answer
A. Directly exposed to nuclear radiations from a high-altitude burst. -
- 32.
What is the reason we cannot draq reliable conclusions about the nature and degree of specific system susceptibility without a detailed test and evaluation?
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All high-altitude electromagnetic pulse vulnerabilities may not be identified
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All system malfunctions may not be corrected
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Overall system system shielding maynot be identified
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Overall environment may not be accessed
Correct Answer
A. All high-altitude electromagnetic pulse vulnerabilities may not be identifiedExplanation
Without a detailed test and evaluation, we cannot draw reliable conclusions about the nature and degree of specific system susceptibility because all high-altitude electromagnetic pulse vulnerabilities may not be identified. This means that there could be potential vulnerabilities in the system that we are unaware of, making it difficult to accurately assess its susceptibility to electromagnetic pulses. Therefore, a detailed test and evaluation is necessary to ensure a comprehensive understanding of the system's vulnerabilities and level of susceptibility.Rate this question:
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- 33.
What type of electromagnetic interference occurs when a receiver responds to off-frequency signals?
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Rusty Bolt
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Co-channel
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Brute force
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Spurious responses
Correct Answer
A. Spurious responsesExplanation
When a receiver responds to off-frequency signals, it is experiencing spurious responses. Spurious responses refer to unwanted or unintended signals that interfere with the desired signal reception. These signals can be caused by various factors such as nearby electronic devices, electromagnetic radiation, or poor signal filtering. Spurious responses can disrupt the proper functioning of the receiver and affect the quality and accuracy of the received signals.Rate this question:
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- 34.
Two types of light sources that are well suited for fiber-optic modems are light-emitting diodes and
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Photo transistors.
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Hybrid photodiodes.
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Semiconductor laser diodes.
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Integrated photodiode/preamplifiers.
Correct Answer
A. Semiconductor laser diodes.Explanation
Semiconductor laser diodes are well suited for fiber-optic modems because they can generate a focused and coherent beam of light that can travel long distances through the fiber-optic cables without significant loss of signal quality. They also have a high modulation bandwidth, allowing for efficient transmission of data. Additionally, semiconductor laser diodes can operate at high speeds and have a small form factor, making them ideal for use in compact and high-performance fiber-optic modems.Rate this question:
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- 35.
To have adequate signal strength at the receiver, either the transmitted power must be sufficiently high or the
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Efficiency of the transmitting and receiving antennas must be high.
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Efficiency of the transmitting and receiving antennas must be low.
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Receiver must be extremely insensitive.
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Receiver must have low gain.
Correct Answer
A. Efficiency of the transmitting and receiving antennas must be high.Explanation
To have adequate signal strength at the receiver, the efficiency of the transmitting and receiving antennas must be high. This means that the antennas are able to effectively capture and transmit the signals without significant loss or degradation. If the antennas have low efficiency, it means that a significant portion of the signal is lost during transmission, resulting in a weaker signal at the receiver. Therefore, for the receiver to receive a strong signal, it is important for the antennas to have high efficiency.Rate this question:
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- 36.
The bending of radio waves as they travel from one medium to another of different density is called
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Diffusion.
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Diffraction.
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Refraction.
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Reflection.
Correct Answer
A. Refraction.Explanation
Refraction is the bending of radio waves as they pass from one medium to another with a different density. This bending occurs due to the change in the speed of the waves as they enter the new medium. Diffusion refers to the spreading out of waves in different directions, while diffraction is the bending of waves around obstacles or through small openings. Reflection is the bouncing back of waves when they encounter a boundary. Therefore, the correct answer is refraction.Rate this question:
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- 37.
What factor determines the amount of westward shift of a satellite?
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Shift.
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Period.
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Air drag.
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Inclination.
Correct Answer
A. Period.Explanation
The amount of westward shift of a satellite is determined by its period. The period of a satellite is the time it takes to complete one orbit around the Earth. A shorter period means the satellite completes its orbit faster, resulting in a greater westward shift. Conversely, a longer period means the satellite takes more time to complete its orbit, resulting in a smaller westward shift. Therefore, the period of the satellite directly influences the amount of westward shift it experiences.Rate this question:
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- 38.
Information contained in the ephemeris data pertain to the
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Predicted satellite orbit.
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Predicted atmospheric conditions.
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Channels through a satellite that are available for use.
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Combinations of ground stations that can communicate with each other.
Correct Answer
A. Predicted satellite orbit.Explanation
The ephemeris data contains information about the predicted satellite orbit. This means that it provides details about the satellite's position and trajectory in space at different times. The data helps in tracking and predicting the movement of the satellite, which is crucial for various applications such as satellite navigation, communication, and scientific research. It does not provide information about atmospheric conditions, available satellite channels, or ground station combinations.Rate this question:
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- 39.
The three general-purpose interface bus handshake lines are “Not Ready for Data,” “Data Valid,” and
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“End or Identify.”
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“Service Request.”
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“Ring-back Invalid.”
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“Not Data Accepted.”
Correct Answer
A. “Not Data Accepted.”Explanation
The correct answer is "Service Request." The three general-purpose interface bus handshake lines are "Not Ready for Data," which indicates that the receiving device is not ready to accept data; "Data Valid," which indicates that the data being transmitted is valid; and "Service Request," which is a signal sent by the receiving device to request service from the sending device. "End or Identify" and "Ring-back Invalid" are not valid terms used in the context of general-purpose interface bus handshake lines. "Not Data Accepted" is not a correct term for one of the handshake lines.Rate this question:
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- 40.
Which fiber-optic connector uses quick-release, keyed bayonet couplings that are preferred in situations where severe vibrations are not expected?
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Biconic.
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Field (FC).
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Straight tip (ST).
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Sub-miniature, type A (SMA).
Correct Answer
A. Straight tip (ST).Explanation
The Straight Tip (ST) fiber-optic connector uses quick-release, keyed bayonet couplings that are preferred in situations where severe vibrations are not expected. This type of connector provides a secure and stable connection, making it suitable for applications where stability is important. The quick-release feature allows for easy installation and removal, while the keyed bayonet couplings ensure proper alignment and prevent accidental disconnection.Rate this question:
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- 41.
Which MIL-STD 1553 coupling technique requires a separate bus coupler unit?
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Direct.
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Mini stub.
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Short stub.
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Transformer.
Correct Answer
A. Transformer.Explanation
The MIL-STD 1553 coupling technique that requires a separate bus coupler unit is the transformer. Transformers are used to couple the bus to the terminals in the system, providing electrical isolation and impedance matching. This allows for effective communication between the bus and the terminals while minimizing signal distortion and interference. The other options, direct, mini stub, and short stub, do not require a separate bus coupler unit as they are different coupling techniques that do not involve the use of transformers.Rate this question:
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- 42.
What source region electromagnetic pulse region has a primarily vertical electromagnetic pulse electric field and what structures are affected?
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Radiated: antennas and boresite feedhorns
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Plasma: antennas and boresite feedhorns
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Secondary: cables and ground wires
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Source: cables and ground wires
Correct Answer
A. Radiated: antennas and boresite feedhornsExplanation
The correct answer is Radiated: antennas and boresite feedhorns. This means that the electromagnetic pulse (EMP) in the radiated source region has a primarily vertical electric field, and it affects antennas and boresite feedhorns. The EMP can induce strong electric currents in these structures, potentially damaging or disrupting their operation.Rate this question:
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- 43.
Wavelength division multiplexing assigns each incoming optical signal to a specific
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Pseudorandom code.
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Frequency of light.
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Radio frequency.
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Time slot.
Correct Answer
A. Frequency of light.Explanation
Wavelength division multiplexing (WDM) is a technique used in optical communication systems to combine multiple optical signals onto a single optical fiber by assigning each signal to a specific frequency of light. This allows for the simultaneous transmission of multiple signals over the same fiber, increasing the overall capacity of the system. Therefore, the correct answer is frequency of light.Rate this question:
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- 44.
Which propagation path is used mainly for line-of-sight communications?
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Sky waves.
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Earth waves.
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Space waves.
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Ground waves.
Correct Answer
A. Space waves.Explanation
Space waves are used mainly for line-of-sight communications. Line-of-sight refers to the direct path between the transmitter and receiver without any obstruction. Space waves propagate in a straight line from the transmitting antenna to the receiving antenna, making them ideal for line-of-sight communication. Sky waves are used for long-distance communication via reflection off the ionosphere, earth waves are used for communication over short distances along the Earth's surface, and ground waves are used for communication over long distances along the Earth's surface.Rate this question:
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- 45.
What is the longest distance across an elliptical orbit called?
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Minor axis.
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Major axis.
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Apogee.
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Perigee.
Correct Answer
A. Major axis.Explanation
The major axis is the longest distance across an elliptical orbit. In an ellipse, the major axis is the line that passes through the center of the ellipse and is the longest distance from one side of the ellipse to the other. This is in contrast to the minor axis, which is the shortest distance across the ellipse. Apogee and perigee, on the other hand, refer to the points in an orbit where an object is farthest and closest to the body it is orbiting, respectively.Rate this question:
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- 46.
High-altitude electronmagnetic pulse is what type of frequency phenomenon, and involves which frequency range?
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Secondary; 1 Hz to 1GHz
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Wideband; 1 Hz to 1 GHz
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Secondary; 10 Hz to 10 GHz
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Wideband; 10 Hz to 10 GHz
Correct Answer
A. Wideband; 1 Hz to 1 GHzExplanation
High-altitude electromagnetic pulse (HEMP) is a wideband phenomenon that involves a frequency range from 1 Hz to 1 GHz. It is a type of electromagnetic pulse that occurs as a result of a nuclear explosion in the Earth's atmosphere. HEMP can cause significant damage to electronic systems and infrastructure over a wide range of frequencies, hence the term "wideband". The correct answer, "Wideband; 1 Hz to 1 GHz", accurately describes the frequency range and type of phenomenon associated with HEMP.Rate this question:
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- 47.
High-altitude electromagnetic pulse environment protection is important for critical, time-urgent mission systems because it
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Has a vertical amplitude that decreases inversely with distance, but remains significant for many kilometers.
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Has very intense radial electrical fields, azimuthal magnetic fields, and time-varying air conductivity.
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Is the only nuclear environment that may be imposed on many systems simultaneously with the expenditure of very few weapons.
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Is a problem for electronic components in satellites and reentry vehicles.
Correct Answer
A. Is the only nuclear environment that may be imposed on many systems simultaneously with the expenditure of very few weapons. -
- 48.
A communications blackout can be produced by large attenuation of the
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Transmitted signal causing the signal-to-noise ratio to fall below unity.
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Transmitted signal causing the signal-to-noise ratio to rise above unity.
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Recieved signal causing the signal-to-noise ratio to be equal to unity.
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Recieved signal causing the signal-to-noise ratio to rise above unity.
Correct Answer
A. Transmitted signal causing the signal-to-noise ratio to fall below unity.Explanation
When the transmitted signal experiences a large attenuation, it means that the signal weakens significantly during transmission. This causes the signal-to-noise ratio to fall below unity, meaning that the level of noise in the signal becomes stronger compared to the actual transmitted signal. As a result, the communication becomes difficult or impossible to decipher, leading to a communications blackout.Rate this question:
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- 49.
The closest point of orbit that a satellite comes to the Earth is called the
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Apogee.
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Perigee
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Major axis.
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Minor axis.
Correct Answer
A. PerigeeExplanation
The closest point of orbit that a satellite comes to the Earth is called the perigee. This term is commonly used in astronomy and space science to describe the point in an orbit where the distance between the satellite and the Earth is at its minimum. The opposite of perigee is apogee, which refers to the point in the orbit where the satellite is farthest from the Earth. The terms major axis and minor axis are not directly related to the closest point of orbit and are more commonly associated with the shape of an ellipse.Rate this question:
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Mar 20, 2023Quiz Edited by
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Jun 24, 2009Quiz Created by
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