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ATT TEST 12 LATEST TEST 2025 (COMPLETE TEST) |
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What develops the characteristic impedance of the transmission line cable? ---------CORRECT ANSWER-----------------Combination of the resistance, capacitance, and inductance of the cable What needs to happen to transfer the maximum amount of energy from the source to the load? ---------CORRECT ANSWER-----------------Impedance must be matched or equal between input and output What is the result of mismatched impedance? ---------CORRECT ANSWER-----------------Damaging standing waves reflected back toward the source, causes loss of power What is skin effect? ---------CORRECT ANSWER-----------------High frequency current that has a tendency to flow to the outside of the conductor What is induction loss? ---------CORRECT ANSWER-----------------When mag field expands and contracts inducing voltage and current into conducting material near the transmission lines What is radiation loss? ---------CORRECT ANSWER-----------------Loss to the atmosphere and not to a nearby object
What type of loss is normally in the form of heat dissipation? --------- CORRECT ANSWER-----------------Dielectric loss How is dielectric loss held to a minimum? ---------CORRECT ANSWER------ -----------High resistance dielectric (insulation) What type of wire has a solid center conductor and a braided outer conductor separated by a dielectric material? ---------CORRECT ANSWER- ----------------Coaxial cable What type of transmission line has very little radiation loss? --------- CORRECT ANSWER-----------------Coaxial cable What cable is used mainly for TV reception and transmission of low power frequencies up to 200MHz? ---------CORRECT ANSWER-----------------Twin Lead line What transmission line is the simplest and least expensive and used for low volts/low frequency? ---------CORRECT ANSWER-----------------Twisted pair What is a waveguide? ---------CORRECT ANSWER-----------------A system of material boundaries capable of guiding electromagnetic energy
What is the iris? ---------CORRECT ANSWER-----------------Metal diaphragm located in waveguide, contains opening called window or aperture (used to provide impedance matching) What is the bending, twisting, joining, and installation of waveguides called? ---------CORRECT ANSWER-----------------Waveguide plumbing What are two classifications of transmitting antennas? ---------CORRECT ANSWER-----------------Hertz and Marconi What is a measure of the antennas ability to focus energy in one or more specific directions? ---------CORRECT ANSWER-----------------Directivity What type of antenna has low directivity? ---------CORRECT ANSWER------- ----------Omnidirectional What is the ability of an antenna to act as a transmitting or receiving antenna? ---------CORRECT ANSWER-----------------Reciprocity The direction of polarization is the direction of _____ ---------CORRECT ANSWER-----------------The electric vector
Radar and microwave antennas are usually _____ ---------CORRECT ANSWER-----------------Directional What are two characteristics of directional antennas? ---------CORRECT ANSWER-----------------Directivity and power gain What antenna is used most often for microwaves? ---------CORRECT ANSWER-----------------Feed horn What antenna is used for height finding and where a highly directive pattern in vertical and broader pattern in horizontal is needed? ---------CORRECT ANSWER-----------------Orange-peel What does RADAR stand for? ---------CORRECT ANSWER----------------- Radio Detection and Ranging What are the purpose of RADAR systems? ---------CORRECT ANSWER---- -------------Measures VELOCITY and LOCATION of an object by determining time required for electronic signal to travel to and from object What can RADAR detect? ---------CORRECT ANSWER----------------- Position, heading, bearing (azimuth), altitude, speed What is LOS? ---------CORRECT ANSWER-----------------Line of Sight, line form radar set directly to object
What part of radar system produces electromagnetic energy in the form of continuous waves or short powerful pulses? ---------CORRECT ANSWER--- --------------Transmitter What part of radar system is an RF switch that permits radar system to use a SINGLE antenna to both receive/transmit? ---------CORRECT ANSWER-- ---------------Duplexer What part of radar system focuses transmitted EM energy into a beam, radiates it out into space, and catches the echo signal? ---------CORRECT ANSWER-----------------Antenna Which part of radar system consists of electromechanical devices such as synchros, servos, and gyros that correctly position antenna? --------- CORRECT ANSWER-----------------Antenna control Which part of radar system amplifies and concerts returned RF echo into video signal? ---------CORRECT ANSWER-----------------Receiver Which part of radar system analyzes video signal from receiver, detects inconsistent returns, and shapes signal for clarity? ---------CORRECT ANSWER-----------------Video processor Which part of radar system uses processed video signals to give operator visual indication of object info? ---------CORRECT ANSWER----------------- Display
How is gain of an active device (amp) or loss of a passive device (attenuator) expressed? ---------CORRECT ANSWER-----------------Decibels (dB) Decibels represent a change in what? ---------CORRECT ANSWER----------- ------Power level What is the ability of a radar to distinguish multiple targets from one another when they are close together? ---------CORRECT ANSWER---------- -------Resolution What are two types of radar resolution? ---------CORRECT ANSWER--------- --------Range and Bearing (angular) resolution What plays a large part in quality of range resolution? ---------CORRECT ANSWER-----------------Pulse Width What is the ability of radar to separate objects at the SAME range but at DIFFERENT bearing or elevation angles? ---------CORRECT ANSWER------ -----------Bearing (angular) resolution What is the ability of the radar to determine range, bearing, and height of an object? ---------CORRECT ANSWER-----------------Radar accuracy
A stationary objects phase is always the _____ ---------CORRECT ANSWER-----------------Same What type of radar transmits a constant flow of EM energy NOT REFERENCED TO TIME? ---------CORRECT ANSWER----------------- Continuous wave Which radar uses multiple antennas to transmit and receive RF energy? ---- -----CORRECT ANSWER-----------------Continuous wave CW radars cannot determine _____ but are used to determine _____? ------ ---CORRECT ANSWER-----------------Range, an objects velocity Which system is similar to continuous wave radar? ---------CORRECT ANSWER-----------------Frequency modulation How do frequency modulation systems work? ---------CORRECT ANSWER- ----------------Compare frequency of received signal to a fixed reference signal What can frequency modulation systems provide that CW can't? --------- CORRECT ANSWER-----------------Range and bearing info
What type of radar provides a way to measure round-trip transmit time of transmitted signal by constantly changing frequency to provide range? ------ ---CORRECT ANSWER-----------------Frequency modulated CW (FM-CW) What type of radar provide range and bearing info to surface contacts, coastal nav points, and slow low-flying aircraft? ---------CORRECT ANSWER-----------------Surface search radar What type of air search radar does the FAA use for commercial air traffic control? ---------CORRECT ANSWER-----------------Long and short range air search radar What does the military use air search radar for? ---------CORRECT ANSWER-----------------Air traffic control and airborne target detection What type of radar is used to land aircraft during periods of low visibility? --- ------CORRECT ANSWER-----------------Specialized 3D radar called precision approach radar (PAR) What type of radars locate targets and direct weapon systems to targets? -- -------CORRECT ANSWER-----------------Tracking radar What do tracking radars provide? ---------CORRECT ANSWER----------------- Range, bearing, and elevation data of one or more targets (very accurate)
What antenna is used to find objects bearing because of a narrow horizontal beam? ---------CORRECT ANSWER-----------------Truncated parabola What are three branches of electronic warfare? ---------CORRECT ANSWER-----------------electronic support measures, electronic counter measures, and electronic counter counter measures Which part of electronic warfare search RF spectrum for emissions and analyze results to exploit weapons or sensors involved? ---------CORRECT ANSWER-----------------Electronic support measures What is the ability of an RF spectrum system to reject unwanted radiations and minimize its own transmissions from causing interferance? --------- CORRECT ANSWER-----------------Electromagnetic compatibility (allows radars to operate at optimum performance level What is referred to as active ECM? ---------CORRECT ANSWER--------------- --Jamming What is a form of passive ECM? - --------CORRECT ANSWER----------------- Chaff (creates clutter or false targets)
What are two categories of electronic counter-countermeasures? --------- CORRECT ANSWER-----------------Denial and deception (active and passive) What type of devices are used to produce signals designed to prevent detection and tracking of targets? ---------CORRECT ANSWER----------------- Active denial ECM What are 5 types of active denial ECM? ---------CORRECT ANSWER-------- ---------CW jamming, spot noise, sweep jamming, sidelobe repeater, barrage noise What is generation of RF noise in particular band or frequency channel to change signal to noise ratio of radar receiver ---------CORRECT ANSWER-- ---------------Spot Noise What type of ECM is uses non-electronic devices to prevent detection and tracking? ---------CORRECT ANSWER-----------------Passive denial What are three types of passive denial ECM? ---------CORRECT ANSWER- ----------------Chaff, reduced radar cross section (RCS), and radar absorbing materials (RAM) What type of ECM uses electronic devices to produce false echo signals to deceive and confuse a radar receiver? ---------CORRECT ANSWER---------- -------Active deception
What are two types of LEDs used for fiber optics? ---------CORRECT ANSWER-----------------Heterojunction and homojunction What does LASER stand for? ---------CORRECT ANSWER----------------- light amplification by stimulated emission of radiation What is responsivity? ---------CORRECT ANSWER-----------------Compares change in the detectors current with the change in incident light power What determines detectors optimum wavelengths? ---------CORRECT ANSWER-----------------Composition
