2A533A Vol.3 Part 2

Frequency hopping is a technique used by HAVE QUICK radios to resist jamming. This technique involves rapidly changing the frequency of the radio signal within a specific range. By constantly changing frequencies, the radio makes it difficult for jammers to disrupt the communication. This method helps to ensure that the radio signal remains secure and reliable even in the presence of intentional interference.

The power supply in a pulse-modulation radar set provides the necessary voltages to operate the other radar components. It supplies the required electrical power to the antenna and transmitter, enabling them to function properly. Without a functioning power supply, the other components would not receive the necessary voltages to operate, resulting in the radar set not being able to function effectively.

Ground mapping is the radar application used to produce a pictorial map of the terrain. This involves using radar technology to collect data about the surface of the Earth and create a visual representation of the terrain. By analyzing the radar echoes and reflections, ground mapping radar can provide detailed information about the topography, vegetation, and other features of the terrain. This information is valuable for various purposes, such as military operations, navigation, and environmental monitoring.

When the received frequency is lower than the transmitted frequency in a frequency-shift radar system, it indicates that the aircraft is flying away from the radar transmitter (RT). This is because the frequency shift occurs due to the Doppler effect, where the frequency of the signal changes based on the relative motion between the transmitter/receiver and the aircraft. A lower received frequency suggests that the aircraft is moving away from the radar, causing a decrease in the frequency of the reflected signal.

The pulse repetition frequency in a pulse-modulation radar system refers to the number of pulses that are transmitted within 1 second. This means that it measures how frequently the radar system sends out pulses of electromagnetic energy. By knowing the pulse repetition frequency, the radar system can determine the range and velocity of the target being detected.

Ultra-high frequency radios are primarily used for line-of-sight communications. This means that they are most effective when there is a direct, unobstructed path between the transmitting and receiving antennas. UHF signals do not penetrate obstacles like buildings or mountains as well as lower frequency signals, so they are ideal for short-range communication over relatively flat terrain. This makes them suitable for applications such as walkie-talkies, mobile phones, and wireless local area networks (WLANs).

The correct answer is phase control modules. Phase control modules are responsible for steering the radio-frequency beam in radar systems. They help in adjusting the phase of the radio waves emitted by the antenna, which determines the direction in which the beam is steered. By controlling the phase, the radar system can scan and track targets effectively. Radio-frequency roll resolver and radio-frequency quadrant manifolds are not directly related to steering the beam, making them incorrect options.

The voltage standing-wave ratio (VSWR) is a measure of how efficiently power is transferred from the transmitter to the antenna. It is determined by comparing the reflected power (power that is not absorbed by the antenna and is instead reflected back) to the TX power (power transmitted by the transmitter). A higher VSWR indicates a greater amount of power being reflected back, which can lead to inefficiencies and potential damage to the transmitter. Therefore, the correct answer is to compare the reflected power to the TX power.

The heterodyning process in an amplitude-modulated transmitter modulator involves mixing two original frequencies. This process results in the creation of two new frequencies - the sum of the two original frequencies and the difference between them. Therefore, the correct answer is that the frequencies created by the heterodyning process are the sum of and difference between the two original frequencies.

Sensitivity refers to the ability of a radio receiver to reproduce weak signals. It determines how well the receiver can detect and amplify low-intensity signals, allowing for better reception and clarity of the transmitted information. A receiver with high sensitivity is able to capture and process weak signals more effectively, resulting in improved performance in areas with low signal strength or interference.

When no frequency shift between the transmitter/receiver and the aircraft can be measured in a frequency-shift radar system, it indicates that they are a constant distance away from each other. This means that there is no change in the frequency of the radar signal as it is reflected back from the aircraft. This could occur when the aircraft is stationary or moving directly towards or away from the transmitter/receiver, resulting in a constant distance between them. It suggests that there is no relative motion between the two entities.

When the received frequency is higher than the transmitted frequency in a frequency-shift radar system, it indicates that the aircraft is flying towards the transmitter/receiver. This is because when an object is moving towards the radar system, the frequency of the reflected radar pulses increases due to the Doppler effect. Therefore, the higher received frequency suggests that the aircraft is approaching the transmitter/receiver.

When two signals are received simultaneously on the same operating net, the HAVE QUICK II radio automatically goes into conferencing by offsetting the second transmitter frequency by 25Khz. This means that the second transmitter's frequency is adjusted by 25Khz to avoid interference and allow for clear communication. This offsetting helps to separate the two signals and ensure that they can be received and understood without interference or overlap.

In a pulse-modulation radar system, heterodyning refers to the process of combining two frequencies to produce a third frequency. In this case, the pulse-modulation radar system produces an intermediate-frequency signal through heterodyning. This intermediate-frequency signal is then used for further processing and analysis in the radar system.

The HF coupler in the arc-190 high-frequency radio system matches the impedance of the antenna to the receiver-transmitter in order to give maximum power transfer. This means that it optimizes the transfer of power from the transmitter to the antenna, ensuring that the maximum amount of power is efficiently transmitted. By matching the impedance, the coupler minimizes signal loss and maximizes the power delivered to the antenna, resulting in effective communication.

A very-high frequency frequency-modulated radio is mainly used on aircraft to contact army ground troops. This type of radio allows for clear and reliable communication between the aircraft and the troops on the ground. It is essential for coordinating operations, relaying important information, and ensuring effective collaboration between the aircraft and the army ground troops.

The antenna in a pulse-modulation radar system shapes the radio-frequency energy into a narrow beam. Antennas are designed to focus and direct the electromagnetic waves in a specific direction, allowing the radar system to accurately detect and track targets. By shaping the radio-frequency energy into a narrow beam, the antenna helps to improve the radar system's range, accuracy, and resolution.

The radar altimeter measures the height above the ground or terrain. When it is tracking the terrain, it means that it is actively sensing and displaying the height information. Therefore, in this situation, the OFF flag will not be displayed because the radar altimeter is functioning properly and providing accurate height readings.

The low observable antenna is the correct answer because it is designed to perform highly accurate electronic beam steering in a radar set. This type of antenna is specifically engineered to minimize its detectability by reducing its radar cross-section, making it difficult for enemy radar systems to detect. It utilizes advanced technology to steer the radar beam precisely and accurately, allowing for effective surveillance and tracking capabilities while maintaining a low profile.

When there is an insufficient amount of return video present during the keyed gain control gate, it indicates that the radar is unable to track or locate a target. In this situation, the radar altimeter mode that is initiated is the "search/loss of track" mode. This mode is used to search for a target or to indicate that the radar has lost track of a target.

The radar application primarily used as an aid to navigation is the "search" radar. This type of radar is specifically designed to detect and locate objects or targets in a wide area, such as ships, aircraft, or other navigational aids. It provides a broad coverage and helps in identifying potential obstacles or hazards, ensuring safe navigation and preventing collisions.

In a frequency-modulated receiver, the discriminator and limiter are two fundamental sections that are electrically different from those in an amplitude-modulated receiver. The discriminator is responsible for converting the frequency variations in the received signal into corresponding voltage variations, allowing the demodulation of the FM signal. On the other hand, the limiter limits the amplitude of the received signal to a constant level, allowing for better noise rejection and signal quality. Therefore, the correct answer is discriminator and limiter.

When a receiving radio antenna receives radio-frequency signals, it does so by electromagnetic fields impressing a voltage across the antenna. This means that the radio-frequency signals create electromagnetic fields that induce a voltage across the antenna, causing a current to flow. This current carries the information embedded in the radio-frequency signals, allowing the antenna to receive and interpret the signals.

The doppler principle in a frequency-shift radar system allows for the measurement of ground speed and drift angle. The doppler principle states that the frequency of a wave will change if the source of the wave is moving relative to the observer. In a radar system, this principle is used to measure the change in frequency of the reflected wave from a moving target. By analyzing this change in frequency, the radar system can determine the ground speed (speed of the target relative to the ground) and the drift angle (angle between the target's direction of motion and the ground track).

The CN-221A radar set component provides stabilized pitch and roll reference data for control of antenna orientation, despite changes in aircraft attitude.

A transmitting radio antenna is considered to be a transducer because it converts energy to magnetic and electrical fields of forces. This means that it takes electrical energy and converts it into a combination of magnetic and electrical fields, which are then transmitted as radio-frequency energy to distant locations.

If the external blower for an arc-190 high frequency radio system is overheating, it will cause a fault in the receiver-transmitter. This fault will then keep the transmitter from functioning properly.

The radar sets dual-channel beam steering controller selectively sends digital phasing and polarization commands to the phase control module.

A non-linear amplifier is used to achieve amplitude modulation by introducing frequencies that are not present in the input signal. Unlike linear amplifiers, which only amplify the input signal without introducing any additional frequencies, non-linear amplifiers modify the input signal by distorting its waveform. This distortion creates new frequencies in the output signal, allowing for the desired amplitude modulation effect.

Ganged tuning is the process used in a typical amplitude-modulated superheterodyne receiver to tune two or more circuits with a single control. This means that when the control is adjusted, it simultaneously adjusts the tuning of multiple circuits in the receiver. This allows for easier and more efficient tuning of the receiver, as multiple circuits can be tuned at once, ensuring proper alignment and synchronization.

The screen display on newer types of pulse modulation radar indicators is referred to as a map. This suggests that the display provides a visual representation of the radar data in a map-like format. This could include information such as geographical features, targets, and other relevant data points. The term "a map" accurately describes the purpose and functionality of the screen display in these radar indicators.

In a frequency-modulated signal, the amount of frequency modulation is controlled by the modulating signals. This means that the modulating signals determine how much the frequency of the carrier signal varies. The amplitude of the carrier signal remains constant, while the frequency changes according to the modulating signals. Therefore, the correct answer is amplitude.

The dimensions of a waveguide determine its frequency and power-handling capabilities. The frequency of a waveguide is determined by its dimensions because different dimensions allow for the propagation of different frequencies. The power-handling capabilities of a waveguide are also influenced by its dimensions as they determine the maximum power that can be transmitted through the waveguide without causing damage or significant power loss. Therefore, the dimensions of a waveguide play a crucial role in determining its frequency range and power-handling capabilities.

When a HF radio control is set to 27.5 Mhz and modulated by a 1000-hz tone, the lower sideband is selected. Lower sideband modulation involves suppressing the carrier frequency and the upper sideband, leaving only the lower sideband. The transmitted frequency is then calculated by subtracting the modulating frequency (1000 Hz) from the carrier frequency (27.5 Mhz). Therefore, the transmitted frequency would be 27.5 Mhz - 1 kHz = 27.499 Mhz.

The correct answer is 30 to 87.975 Mhz. This frequency range is within the VHF (Very High Frequency) band, which typically spans from 30 to 300 Mhz. The FM (Frequency Modulation) mode is commonly used for VHF radio communication. Therefore, a VHF radio receiver operating in FM mode would have a frequency range within the VHF band, such as 30 to 87.975 Mhz.

The advantage of the remote HAVE QUICK II configuration over the panel-mount configuration in an aircraft is that it reduces cost by using existing aircraft wiring. This means that there is no need for additional wiring installation, saving both time and money. The remote configuration utilizes the existing wiring infrastructure of the aircraft, making it a more cost-effective option compared to the panel-mount configuration.

The major drawback in using a single-sideband (SSB) receiver over an amplitude-modulated (AM) receiver is the need for critical frequency stability. This means that the SSB receiver requires a more precise and stable frequency in order to properly demodulate the signal. In contrast, an AM receiver only requires one oscillator circuit, which makes it less demanding in terms of frequency stability. Additionally, the SSB receiver has a narrower bandpass, which can limit its ability to receive a wide range of frequencies.

The radar altimeter test button is used to test the low-altitude fly-up circuits in the radar data terminals and terrain following ACUs. This means that when the test button is pressed, it allows for the evaluation of the functionality and performance of these specific components. The radar data terminals are responsible for processing and displaying radar information, while the terrain following ACUs are in charge of controlling the aircraft's altitude based on the radar data. Therefore, testing these circuits is crucial to ensure the proper functioning of the radar altimeter system.

The correct answer is "amplitude variations of the intermediate frequency signal." In an amplitude-modulated receiver, the detector circuit is designed to detect and extract the audio signal from the carrier wave by responding to the variations in the amplitude of the intermediate frequency signal. The amplitude variations represent the information being carried in the modulated signal, such as sound or data, and the detector circuit is responsible for demodulating and extracting this information for further processing.

The correct answer is 108 to 151.975 Mhz. This frequency range is specified for the arc-186 very-high frequency radio receiver in the amplitude modulation mode. It means that this radio receiver is capable of receiving signals within this frequency range when operating in the amplitude modulation mode.

In a signal-sideband system, the independent sideband mode of operation transmits both sidebands and deletes the carrier. This means that the carrier signal, which is the unmodulated signal in an amplitude modulation system, is removed from the transmitted signal. The independent sideband mode allows for efficient use of bandwidth by transmitting only the necessary information contained in the sidebands, without the need for the carrier signal.

In a single-sideband transmitter, the balance modulator's output consists of the carrier and upper and lower sidebands. This means that the modulator generates two additional signals, one above the carrier frequency (upper sideband) and one below the carrier frequency (lower sideband). These sidebands contain the information that needs to be transmitted, while the carrier frequency helps in the demodulation process at the receiver end. By transmitting only the sidebands and not the carrier, single-sideband modulation allows for more efficient use of bandwidth and power.

A shielded pair is the radio-frequency line that has uniform capacitance between the conductors throughout the length of the line. This means that the capacitance remains constant along the entire length of the line, providing consistent performance and signal transmission. The shielded pair design helps to minimize interference and noise, making it suitable for applications where signal integrity is crucial.

The correct answer is "transmit-only mode of operation of normal and secure voice from 108.000 to 117.9975 Mhz amplitude modulated." This means that the an/arc-210 receiver/transmitter is capable of transmitting normal and secure voice signals in the specified frequency range using amplitude modulation. However, it does not provide the capability for half-duplex, two-way communications or receiver-only mode of operation.

In a frequency-modulated signal, the amount of separation between the sideband frequencies is equal to the carrier frequency. This means that the sideband frequencies, which are produced as a result of modulation, are located symmetrically around the carrier frequency. The carrier frequency remains unchanged, while the sidebands are shifted in frequency according to the modulation. Therefore, the separation between the sideband frequencies is directly proportional to the carrier frequency.

The purpose of the keyed automatic gain control gate while the radar altimeter is in track mode is to control the processing of the ground returns. This means that the gate helps to regulate the amplification of the radar signals that are received from the ground. By controlling the gain, the gate ensures that the radar altimeter accurately detects and measures the distance between the aircraft and the ground. This helps in providing reliable altitude information to the pilot.

The arc-186 very-high frequency radio cannot transmit in the amplitude modulation mode on frequencies ranging from 108 to 151.975 MHz.

The low-pass filter in the automatic frequency control circuitry of a frequency-modulated transmitter is designed to prevent correction voltage changes caused by the modulating signals. This is because the modulating signals can introduce unwanted variations in the frequency of the transmitter's carrier signal. The low-pass filter helps to smooth out these variations and stabilize the carrier frequency, ensuring that the transmitted signal remains within the desired frequency range.

Very-high frequency frequency modulation has the best chance of receiving a signal from a station located beyond the horizon. This is because frequency modulation allows for better signal quality and less interference compared to amplitude modulation. Very-high frequency also has a shorter wavelength which allows it to diffract and bend around obstacles, enabling it to reach beyond the horizon.

The basic difference between the single sideband (SSB) receiver and the conventional superheterodyne receiver is that the SSB receiver uses a special detector and carrier reinsertion oscillator. This means that instead of using a discriminator and local oscillator circuit like the conventional superheterodyne receiver, the SSB receiver has a special detector that is capable of extracting the desired sideband signal and a carrier reinsertion oscillator that helps to reconstruct the carrier signal. This allows the SSB receiver to effectively demodulate and recover the original signal, while eliminating the unnecessary sideband and carrier components.