2A251 Volume 3 UREs

Frequency-hopping is a technique used by Have Quick (HQ) radios to resist jamming. This technique involves rapidly changing the frequency of the radio signals over a wide range of frequencies. By constantly switching frequencies, the radios make it difficult for jammers to interfere with the communication. This is because the jammers would need to continuously adjust their frequency to match the hopping pattern, which is challenging to achieve in real-time. Therefore, frequency-hopping helps to ensure secure and uninterrupted communication for HQ radios.

The correct answer is 30. This suggests that the underwater acoustical beacon can transmit for approximately 30 days before its battery power is depleted.

The correct answer is the underwater acoustical beacon (UAB). This system emits pulses of high-frequency sound and is used for emergency communications. It is specifically designed to be used underwater, making it ideal for situations where an aircraft has crashed into water and needs to be located. The UAB emits these sound pulses, which can be detected by search and rescue teams using specialized equipment, allowing them to locate the aircraft and initiate rescue operations.

A very-high frequency (VHF) frequency modulated (FM) radio is mainly used on aircraft to contact ground forces. This means that the radio is primarily used for communication between the aircraft and ground personnel, such as military troops or support teams. It allows the aircraft to relay important information, coordinate operations, and receive instructions from the ground forces.

The emergency locator transmitter (ELT) is designed to survive an impact of up to 100 Gs. Gs, or gravitational forces, are a unit of measurement used to describe the force experienced by an object during acceleration or deceleration. In the case of an ELT, it is crucial for it to withstand high impact forces in the event of a crash or accident. A rating of 100 Gs indicates that the ELT is built to withstand a significant amount of force, ensuring its functionality and ability to transmit distress signals even in severe conditions.

The correct answer is Maintenance BIT (MBIT). This is the built-in-test that is activated by pressing the BIT pushbutton switch on the airborne digital interphone system (ADIS) interphone audio control panel (IACP). MBIT is a self-diagnostic feature that allows for the continuous monitoring and testing of the system's components and functions. By pressing the BIT pushbutton switch, the system initiates the MBIT process to identify any faults or failures in the interphone audio control panel and its associated components. This helps in ensuring the system's reliability and performance during flight operations.

The battery in the KY-58 processor is used to prevent the automatic zeroing of the codes after the aircraft power is removed. This means that even if the power to the aircraft is turned off, the battery will ensure that the codes stored in the processor are not lost or reset. This is important for maintaining the security and integrity of the secure voice system, as the codes are crucial for encryption and decryption of communications.

When the lower sideband mode is selected, the transmitted frequency is slightly lower than the carrier frequency. In this case, the carrier frequency is set to 25.000 MHz and it is modulated by a 1000 Hz tone. The lower sideband will be 1000 Hz below the carrier frequency, resulting in a transmitted frequency of 24.999 MHz.

The high pass filter is installed on the ARC-210 radio system to attenuate frequency-modulated (FM) commercial stations below 108 megahertz (MHz). This means that the filter is designed to reduce the strength or intensity of FM signals from commercial stations that are below the frequency of 108 MHz. By doing so, the filter helps to prevent interference from these stations and ensures that the radio system can effectively transmit and receive signals within its intended frequency range.

The CALL switch activates the AGC circuits in all aircraft control panels' headset amplifiers, which results in the CALL audio being heard 6 dB louder than any other signals present.

The correct answer is "Hot-mic." The hot-mic function allows crewmembers to communicate with other aircraft positions without having to press the microphone button. This means that their microphone is always active, allowing for constant communication without the need to manually activate the microphone.

The major difference between the U92A/U and the U94A/U jack on the C-6624/AIC-25 interphone station's H-78/A1C headset/microphone is that the U94A/U has a PTT button located on the pilot's throttle grip. In contrast, the U92A/U requires an additional wire for the TALK switch. This means that the U94A/U allows the pilot to easily activate the push-to-talk function without needing an extra wire, making it more convenient to use in the cockpit.

The correct answer is 108 to 151.975. This range represents the frequency range of the ARC-186 VHF radio receiver in the receive AM mode.

The +17 to +19-voltage direct current (VDC) on the CALL control line of the C-6567 interphone set control is used to activate the automatic gain control (AGC) circuits in the headset amplifiers. This voltage is necessary to regulate and adjust the amplification levels of the audio signals in order to maintain a consistent and optimal volume for the user. By activating the AGC circuits, the interphone set can automatically adjust the amplification based on the incoming audio signal, ensuring clear and balanced communication.

The CYZ-10 data transfer device (DTD) is classified by installing the crypto ignition key. The crypto ignition key is a security measure that allows access to encrypted data on the DTD. By installing this key, the DTD can securely transfer data and ensure that only authorized personnel can access it. This classification method ensures that sensitive information is protected and only accessible to those with the proper authorization.

If the external blower for an ARC-190 high-frequency radio system is overheating, it can cause the transmitter to stop functioning. This is because the external blower plays a crucial role in cooling down the system, and if it is overheating, it will not be able to effectively cool the transmitter, leading to its malfunctioning.

The correct answer is that the C-11029/ARC-186 is considered a true communications/navigation control box because it controls both the very-high frequency (VHF) radio and the VHF-omnirange/instrument landing system (VOR/ILS) receiver. This implies that it has the capability to manage and regulate both the communication and navigation functions of the aircraft.

The cryptographic KOI-18 loading device is designed to convert an eight level punched tape data to a serial output. This means that it takes the data stored in the punched tape and converts it into a format that can be transmitted or processed serially. This conversion allows for easier transfer and manipulation of the data, making it more efficient and practical to use.

The radio TRANSMITTER SELECTION switch is a crucial component in an aircraft's communication system. It is a seven-position rotary switch that enables the aircrew to select and transmit on each radio system and the interphone. This means that the switch allows the crew to choose which radio system they want to use for communication and also enables them to transmit their messages through the interphone system. Additionally, the switch also allows the crew to monitor the aircraft emergency warning tones, tune each radio system, and select the radio transmitter frequencies.

The correct answer is two-button operation because it allows pilots and copilots to talk on radios and maintain communication with the crew. This is important because effective communication is crucial in aviation for ensuring safety and coordinating actions between the flight crew. Having a two-button operation enables pilots and copilots to easily switch between interphone communication and radio communication, allowing them to stay connected with the crew and external parties simultaneously.

The correct answer is 7000 because the question asks about the number of frequencies available for the tunable main receiver in the ARC-164 ultra-high frequency (UHF) radio. Therefore, out of the given options, 7000 is the most suitable choice as it represents the number of frequencies available for use.

The correct answer is offsetting the second transmitter frequency by 25 kilohertz. When two signals are received simultaneously on the same operating net, the Have Quick II radio automatically goes into conferencing by offsetting the frequency of the second transmitter by 25 kilohertz. This helps to prevent interference and ensure clear communication between the two signals. By offsetting the frequency, the radio is able to distinguish between the two signals and maintain effective communication.

The Z-AHQ adapter is the secure voice component that will be used to integrate the KY-58 processor into existing aircraft installations.

The advantage of the remote Have Quick II configuration over the panel mount configuration in an aircraft is that it reduces cost by utilizing the existing aircraft wiring. This means that there is no need for additional wiring installation, resulting in cost savings for the aircraft owner.

The crash position indicator (CPI) is an emergency communications system that is deployed from an aircraft before or at impact to increase its chances of surviving a crash. It is designed to help locate the aircraft in the event of a crash by emitting a distress signal. The CPI is typically equipped with a radio transmitter and a GPS system, allowing search and rescue teams to quickly and accurately locate the crash site. Unlike the other options, the CPI specifically refers to a system used for indicating the position of the aircraft during a crash.

The correct answer is that the internal clamp is missing. This means that there is no mechanism in place to secure the wires in the U-94A/U headset/microphone connection on the C-6624/AIC-25 interphone station. Without the clamp, the wires can easily pull loose, resulting in a loose connection.

The primary reason a high frequency (HF) radio uses single sideband (SSB) modulation is that it provides many channels on which to operate. SSB modulation allows for more efficient use of the limited available bandwidth in the HF spectrum by eliminating the need for a carrier signal and one sideband. This enables multiple channels to be transmitted within the same frequency range, increasing the number of available communication channels for HF radios.

The pressurized tuner assembly helps prevent high voltage arcing within the HF coupler at high altitudes. By maintaining a higher pressure inside the tuner assembly, it creates a barrier that prevents the formation of arcing, which can be caused by the high altitudes and the associated changes in air pressure. This pressurized environment ensures that the HF coupler remains protected and functions properly, allowing for reliable communication in high altitude conditions.

Connecting all interphone audio common lines to ground at a single point helps to minimize the stray electromagnetic radiation from being picked up by the system. By grounding the common lines, any stray electromagnetic radiation that may be present is directed away from the audio circuits, reducing the chances of interference or noise being introduced into the system. This grounding technique helps to maintain the integrity and quality of the audio signals transmitted through the interphone system.

When connecting the WM-85/U interphone cable to the U-94A/U jack on the C-6624/AIC-25 interphone station's H-78/A1C headset/microphone, the wire color that is connected to the push-to-talk (PTT) button is yellow.

The term "control" is used to describe the lines that determine whether a transceiver connected to the intercom system will be in a transmit or receive condition. These control lines play a crucial role in managing the communication flow between the transceiver and the intercom system, allowing the user to switch between transmitting and receiving audio signals as needed.

The presence of a valid key loaded into the KYK-13 cryptographic loading device is indicated by one red indicator flash. This flash serves as a confirmation that a valid key has been successfully loaded into the device.

The TSEC secure voice processor is the correct answer because it is specifically designed to transmit and receive secure voice messages. The other options, such as the Z-AHQ adapter, remote control unit control panel, and KYK-13 fill device, do not have the primary function of secure voice communication.

The HAVE QUICK II multiple word-of-day (MWOD) modification allows for entering up to six words for a usage period of six days. This modification provides loading capability for a specific number of words and days, allowing for efficient communication and operation within a set time frame.

The correct answer is 8.0 megahertz (MHz). This frequency is not reserved for emergency use. The other frequencies listed, 40.5 MHz, 121.5 MHz, and 243.0 MHz, are all reserved for emergency communication purposes.

The emergency locator transmitter (ELT) is a device that is activated in emergency situations to transmit distress signals and help rescuers locate the aircraft or vessel in distress. The correct answer states that when activated, the ELT continues transmitting on frequencies 121.5 and 243.0 MHz. These frequencies are commonly used for emergency distress signals and are monitored by search and rescue organizations. By transmitting on these frequencies, the ELT increases the chances of being detected and located by rescue teams.

If a second operator keys a transmitter that is already keyed, the second operator's IACP will display the message "NO TX". This means that the transmitter is already in use and the second operator cannot transmit at that moment.

If the punched tape is left in the KOI-18 cryptographic loading device for an extended period of time, the device will continue to consume power from its battery. As a result, the battery will eventually run down and lose its charge. This can lead to the device shutting down or becoming inoperable until the battery is recharged or replaced.

If 12 cryptographic keys need to be stored, two KYK-13 cryptographic loading devices will be required. Each device can store up to six cryptographic keys, so two devices are needed to accommodate all 12 keys.

The cryptographic CYZ-10 data transfer device (DTD) is primarily used for processing communications security (COMSEC) variables, storing electronic keying material, and storing frequency-hopping data. However, it is not designed to process host/application data.

The KYK-13 fill device is needed to transfer cryptographic variables into the KY-58 processor. This device is specifically designed for this purpose and allows for the secure transfer of cryptographic keys and variables. It ensures that the correct encryption keys are loaded into the KY-58 processor, enabling secure communication and encryption.

The explanation for the correct answer is that the ARC-190 HF radio system receiver-transmitter (RT) only operates properly when it has a CU-2275(V)1 HF antenna coupler installed. This implies that the RT-1341(V)1 is the version of the radio system that is compatible with the CU-2275(V)1 antenna coupler. The other versions, RT-1341(V)2, RT-1341(V)3, and RT-1341(V)4, may not have the necessary compatibility with the antenna coupler, so they would not operate properly with the ARC-190 HF radio system.

Frequency modulated (FM) homing is the correct answer because it is a VHF radio system that utilizes two antennas. This system is commonly used in aviation and maritime applications for navigation and tracking purposes. By using two antennas, FM homing can determine the direction of a signal source by comparing the strength of the signal received by each antenna. This allows for accurate and reliable tracking of signals in VHF frequencies.

The component used to control the ARC-210 radio system if the dual integrating processing center (IPC) fails is the Radio set control. This control allows the user to manage and operate the radio system directly, bypassing the IPC. In the event of a failure in the IPC, the radio set control ensures that communication can still be maintained and controlled effectively.

The PRC-90 emergency radio is designed for search and rescue operations. It is capable of Morse code communication, two-way voice communication, and variable audio modulation between 1000 and 300 hertz. However, three-way voice communication is not a feature of the PRC-90 emergency radio.

When the airborne digital interphone system (ADIS) is in emergency mode, interphone audio control panel (IACP) #3 (Navigator) is directly paired with high frequency radio #1. In emergency mode, it is crucial for the navigator to have direct access to the high frequency radio #1, as it is typically used for emergency communications and long-range communication. This direct pairing ensures that the navigator can quickly and efficiently communicate during emergency situations.

The word-of-day feature is used to program the frequency-hopping pattern and rate of Have Quick II radios. This feature involves assigning a specific word for each day, which is then used to determine the frequency-hopping sequence for that day. By programming the radios with the word-of-day, the radios can synchronize their frequency-hopping patterns, ensuring secure and reliable communication.

The CYZ-10 data transfer device (DTD) is a cryptographic equipment that has a sealed case with three external openings. This suggests that the device is designed with three openings for connecting cables or other devices for data transfer purposes. Having multiple openings allows for flexibility in connecting various peripherals or devices to the DTD, enhancing its functionality and usability.

The crewmembers address the secure voice system through the interphone system. The interphone system allows them to communicate internally within the aircraft, including accessing the secure voice system. The other options mentioned, such as the AN/ARC 210 switch panel, KY-100 mode control panel, and Have Quick II radio set control, may have different functions but do not directly address the secure voice system. The interphone system is specifically designed for internal communication within the aircraft, making it the correct answer in this context.

The HAVE QUICK II panel-mount configuration is primarily used in new aircraft. This suggests that this configuration is specifically designed and implemented in newly manufactured aircraft rather than being used for retrofitting older aircraft. This could be because the panel-mount configuration is more easily integrated into the design and construction process of new aircraft, ensuring optimal functionality and compatibility with other systems.