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2009 Element 6 pool
613 / 616 questions need explanations
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The magnetic force which remains in a substance after the original magnetizing force has been removed is known as:
  • Reluctance (25% chose this)
  • Residual magnetism (50% chose this)
  • Permeability (25% chose this)
  • Hysteresis (0% chose this)
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If the crystal will undergo very small changes in its operating frequency with relatively large temperature variations:
  • A high-temperature coefficient crystal (33% chose this)
  • A low-temperature coefficient crystal (33% chose this)
  • A constant-temperature coefficient crystal (33% chose this)
  • None of the above (0% chose this)
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The speed of a synchronous motor is determined:
  • By the number of pairs of poles (0% chose this)
  • By the line frequency (29% chose this)
  • By the load (14% chose this)
  • A & B (57% chose this)
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In general, shielding between RF amplifier stages:
  • Prevents electromagnetic coupling (17% chose this)
  • Prevents electrostatic coupling (0% chose this)
  • Improves the overall stability of a receiver (17% chose this)
  • All of the above (67% chose this)
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In connecting head telephones directly in the plate circuit of a vacuum tube one should observe the proper polarity:
  • To maintain maximum sensitivity in the headphones (17% chose this)
  • So its current flows opposed to the field strength of the permanent magnet (0% chose this)
  • A & B (50% chose this)
  • None of the above (33% chose this)
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How frequently must the quantity of fuel in the supply tank for use with an oil or gas driven emergency generator be checked while the vessel is in the open sea?
  • Once a week (0% chose this)
  • Every 12 hours (25% chose this)
  • Every 48 hours (0% chose this)
  • Once daily (75% chose this)
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The chemical composition of the electrolyte in an Edison-type storage cell:
  • Is contained in a nickel-plated sheet steel tank (0% chose this)
  • Has a specific gravity of about 1.200 (25% chose this)
  • Is a 21% solution of potassium and lithium hydroxides in distilled water (25% chose this)
  • All of the above (50% chose this)
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What factors determine the charge stored in a capacitor?
  • Capacitance of the capacitor (0% chose this)
  • The applied voltage (0% chose this)
  • Both A & B (75% chose this)
  • None of the above (25% chose this)
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The maximum power that can be safely and continuously dissipated in heat on the plate:
  • Maximum plate dissipation (33% chose this)
  • Maximum power dissipation (33% chose this)
  • Continuous plate dissipation (17% chose this)
  • Plate heat dissipation (17% chose this)
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A dynatron oscillator is a ____ which depends upon the negative resistance characteristic of a tetrode tube for its operation:
  • Tuned circuit operation (0% chose this)
  • Diode detector (50% chose this)
  • Magnetron oscillator (25% chose this)
  • Meystron oscillator (25% chose this)
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Modulation of an RF carrier produces in the plate circuit of the last radio stage of the system:
  • High-level modulation (40% chose this)
  • Low-level modulation (20% chose this)
  • Medium-level modulation (0% chose this)
  • None of the above (40% chose this)
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If the polarity is reversed when charging a storage cell:
  • No damage in a lead-acid cell unless excessive (0% chose this)
  • Damage in an Edison-cell (0% chose this)
  • No damage in an Edison-cell if temperatures below 115 degrees Fahrenheit (33% chose this)
  • A & C (67% chose this)
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What is the definition of a "station open to public service"?
  • A station which handles public correspondence (33% chose this)
  • Paid or toll messages (0% chose this)
  • Radiotelephone facilities for the general public at prescribed rates (17% chose this)
  • All of the above (50% chose this)
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A series-fed plate circuit of a vacuum tube amplifier has a short circuit of the plate bypass capacitor. What happened?
  • It would short out the power supply (17% chose this)
  • It would remove the plate voltage (17% chose this)
  • It would possibly damage the power supply (17% chose this)
  • All of the above (50% chose this)
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A capacitor is sometimes placed in series with the primary of a power transformer:
  • To improve the power factor (50% chose this)
  • To improve output voltage regulation (33% chose this)
  • To rectify the primary windings (0% chose this)
  • None of the above (17% chose this)
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To obtain maximum response to weak CW signals with a superheterodyne receiver:
  • RF gain control should be fully advanced (0% chose this)
  • BFO control varied to obtain the clearest tone (14% chose this)
  • AVC advanced to the best volume (0% chose this)
  • All of the above (86% chose this)
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Who may install, maintain or adjust radiotelephone transmitters which radiate less than 50 watts carrier power?
  • Anyone under the immediate supervision and responsibility of a person holding a first of second class radiotelegraph or general radiotelephone operator license (60% chose this)
  • Only a properly licensed radiotelephone operator (0% chose this)
  • Any holder of a marine radio operator permit or higher (20% chose this)
  • Only persons holding an operator certificate containing a ship radar endorsement (20% chose this)
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Permanent magnets used in head telephones:
  • Place the diaphragms under tension so that the sensitivity of the telephones will be increased (14% chose this)
  • Improve the frequency response (14% chose this)
  • Prevents production of second harmonics in the telephones (14% chose this)
  • All of the above (57% chose this)
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If the circuit breakers refuse to stay closed when you place the emergency batteries on charge, what is the trouble?
  • Internally shorted cells (0% chose this)
  • Reversed charging polarity (0% chose this)
  • Grounded circuit connections (0% chose this)
  • Any of the above (100% chose this)
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How does a radiotelegraph operator transmit a routine call to another station?
  • The letters "CQ" are followed by the call sign of the station called and the call sign of the originating station (20% chose this)
  • The station is called not more than twice, followed by the word "DE" and the call sign of the calling station not more than twice (40% chose this)
  • The originating station must obtain permission from the nearest public coast station (20% chose this)
  • Routine calls are initiated by using the appropriate service abbreviation (20% chose this)
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A 3 HP 100 V DC motor is 85% efficient when developing its rated output. What is the current?
  • 23.93 A (14% chose this)
  • 25 A (43% chose this)
  • 20 A (29% chose this)
  • 8.5 A (14% chose this)
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Which is not the principle advantage of transformer coupling compared to resistance coupling in audio-frequency amplifiers?
  • Greater gain per stage (0% chose this)
  • Can provide necessary impedance matching (33% chose this)
  • A & B (50% chose this)
  • A transformer is expensive, heavy, and bulky (17% chose this)
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What is indicated if a voltmeter connected between the negative side of a ship's DC line and ground reads the full line voltage?
  • It indicates that the voltmeter leads are reversed (0% chose this)
  • This indicates that the positive side of the line, rather then the negative side is grounded (20% chose this)
  • The generator terminals should be reversed (0% chose this)
  • Both B & C are correct (80% chose this)
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Given the current and resistance of the base of a Marconi antenna, what would be the formula for determining the power?
  • P = watts x amps (17% chose this)
  • P = amps. squared x resistance (33% chose this)
  • P = current x resistance (17% chose this)
  • None of the above (33% chose this)
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Lack of requirement for neutralizing, except at ultra high frequencies, is an advantage of a tetrode over ____:
  • A Triode (25% chose this)
  • A Pentode (0% chose this)
  • A & B (75% chose this)
  • None of the above (0% chose this)
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Given a solenoid with a resistance of 5 ohms and 0.34 through the winding when 1108 at 60 Hz is applied. What is the impedance?
  • 367 ohms (20% chose this)
  • 350 ohms (0% chose this)
  • 360 ohms (40% chose this)
  • None of the above (40% chose this)
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What conditions must be met before two AC generators can be operated in parallel?
  • Output voltages must be equal, frequencies must match (0% chose this)
  • Phase rotation, and relative phase positions must match (33% chose this)
  • A & B (67% chose this)
  • None of the above (0% chose this)
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Some superheterodyne receives employ a crystal-controlled oscillator:
  • To insure maximum stability of operation (75% chose this)
  • To reduce noise generated by a conventional oscillator (0% chose this)
  • Because it require no shielding (0% chose this)
  • To control feedback (25% chose this)
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Distilled water should be added to a lead-acid storage cell:
  • To keep the electrolyte 1/4 inch above the to of the plates (20% chose this)
  • To keep the useful plate area sufficient to maintain the full capacity of the cell (0% chose this)
  • None of the above (0% chose this)
  • A & B (80% chose this)
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When the field of a shunt-wound DC motor opens while the machine is operating under no load:
  • The motor would race, and if unchoked, might destroy itself (80% chose this)
  • The motor would quit running without damage (20% chose this)
  • The motor would burn out the field coils (0% chose this)
  • None of the above (0% chose this)
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Why should there be ventilation to the room housing a large group of storage cells?
  • To prevent gas accumulation (0% chose this)
  • To prevent overheating (17% chose this)
  • To prevent the terminals from shorting (0% chose this)
  • A & B (83% chose this)
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One wave-length is:
  • The distance a wave will travel in the time for one cycle (33% chose this)
  • Centimeter wavelength = 30,000 / frequency MHz (17% chose this)
  • A and B (50% chose this)
  • Neither A or B (0% chose this)
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The charge of a lead-acid storage cell:
  • May be determined by hydrometer readings (25% chose this)
  • By measuring voltage under a heavy load (0% chose this)
  • A or B (75% chose this)
  • None of the above (0% chose this)
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Decoupling networks in the plate circuit of a multistage audio amplifier:
  • Prevents oscillations from occurring in the amplifier (40% chose this)
  • Result in oscillations in the amplifier (20% chose this)
  • Allow variable oscillations in the amplifier (0% chose this)
  • None of the above (40% chose this)
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"The temperature coefficient of a y-cut crystal is positive" means:
  • The operating frequency of the crystal will decrease as the temperature decreases (0% chose this)
  • The operating frequency of the crystal will increase as the temperature increases (29% chose this)
  • The operating frequency of the crystal will decrease as the temperature increases (0% chose this)
  • A & B (71% chose this)
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Advantage of crystal control over tuned circuit oscillators:
  • Very high Q (0% chose this)
  • Compact size (0% chose this)
  • Excellent frequency stability (40% chose this)
  • All of the above (60% chose this)
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The advantage of a single-button carbon microphone:
  • High output voltage (0% chose this)
  • Sensitivity (17% chose this)
  • Low cost (17% chose this)
  • All of the above (67% chose this)
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A plate choke in a Heising modulator:
  • Builds up audio modulating voltages (14% chose this)
  • Feeds audio modulating voltages to the plate of the RF modulated amplifier to produce plate modulation (43% chose this)
  • A and B (29% chose this)
  • None of the above (14% chose this)
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The tendency of a tank circuit to keep oscillating for a time after the excitation energy has been removed is:
  • Push-pull effect (20% chose this)
  • Flywheel effect (60% chose this)
  • Polarizing effect (20% chose this)
  • Parasitic oscillation (0% chose this)
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If the dielectric constants of a capacitor dielectric material between the capacitor plates were changed from 1 to 1:
  • The capacitance would be twice its original value (40% chose this)
  • The capacitance would be half its original value (20% chose this)
  • The capacitance would decay rapidly (0% chose this)
  • None of the above (40% chose this)
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The product of the number of turns and the current in amperes used to describe relative magnitude is:
  • Ampere turns (75% chose this)
  • Joules per second (0% chose this)
  • Push-pull convergence (0% chose this)
  • Dissipation collection (25% chose this)
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What is the relationship between a master and a slave station in reference to LORAN navigation systems?
  • A master station originates the RF pulse which then travels in all directions and is intercepted by the slave station (40% chose this)
  • The slave station originates the RF pulse (0% chose this)
  • There must be at least two slave stations (20% chose this)
  • All of the above (40% chose this)
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Field intensity is:
  • Directly proportional to the antenna current (14% chose this)
  • Inversely proportional to the antenna current (14% chose this)
  • Directly proportional to the square of the antenna current (29% chose this)
  • Directly proportional to the square root of the antenna current (43% chose this)
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What is a method of link coupling between two R-F amplifier stages?
  • The coupling together of two circuits which may be separated by a relatively large distance with low-impedance (0% chose this)
  • The coupling together of two circuits which may be separated by a relatively short distance (33% chose this)
  • Isolating one R-F amplifier stage by using a closed loop coupler (17% chose this)
  • Either B or C (50% chose this)
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The opposition to the creation of magnetic lines of force in a magnetic circuit is known as:
  • Reluctance (67% chose this)
  • Hysteresis (17% chose this)
  • Permeability (0% chose this)
  • Eddy currents (17% chose this)
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A short in the armature coils of a DC motor causes:
  • No excessive sparking at the commutator brushes (0% chose this)
  • No overheating of the motor (17% chose this)
  • Reduction of speed under load, and excessive armature current (17% chose this)
  • All of the above (67% chose this)
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Secondary cells:
  • Can be recharged (25% chose this)
  • Cannot be recharged (0% chose this)
  • The products of the chemical change are not soluble in the electrolyte (25% chose this)
  • A & C (50% chose this)
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Bias voltage on the grid of an AF amplifier tube:
  • Determines the operating conditions of the tube (0% chose this)
  • The correct value is essential for undistorted Class A output (33% chose this)
  • In power amplifiers the plate current must be limited to safe value not to exceed the rated plate dissipation of the tube (17% chose this)
  • All of the above (50% chose this)
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The auto-alarm signal is:
  • Four consecutive dashes from C.5 to D.5 seconds, separated by spaces ranging from 0.1 to 0.5 seconds. The combination may not exceed 5 seconds (20% chose this)
  • Three consecutive dashes from D.5 to 5.5 seconds, separated by spaces ranging from 0.5 to A.0 seconds (40% chose this)
  • Five consecutive dashes from B.5-3.5 seconds, separated by spaces ranging from 0.01 to 0.25 seconds. The combination may not exceed 5 seconds (20% chose this)
  • None of the above (20% chose this)
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The determining factor of the setting of the sensitivity control of an auto-alarm receiver:
  • Prevailing static at a given time (0% chose this)
  • Radio interference at a given time (0% chose this)
  • Signal strength (25% chose this)
  • A & B (75% chose this)
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Why is a push-pull audio frequency amplifier preferable to a single-tube stage?
  • When compared with a single-tube stage, power output is doubled (57% chose this)
  • When compared with a single-tube stage, power output is the same (14% chose this)
  • When compared with a single-tube stage, power output is cut in half (29% chose this)
  • None of the above (0% chose this)
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Indications of a defective vacuum tube in a transmitter:
  • Gas blow within the tube, excessive plate color due to overheating (0% chose this)
  • No light from the filament, insufficient plate current, reduced output (40% chose this)
  • Excessive plate current, possible internal arcing, fluctuating plate or grid current (0% chose this)
  • All of the above (60% chose this)
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When the auto-alarm bell rings, what should the operator do?
  • Proceed immediately to the radio room and press the reset button (17% chose this)
  • If the bell stops, the operator should listen for further signals (0% chose this)
  • Both A & B (83% chose this)
  • None of the above (0% chose this)
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To maintain a group of storage cells in good operating condition:
  • Observe correct charge and discharge rates (0% chose this)
  • Overcharge about once a month to remove sulfation (0% chose this)
  • Keep all terminal corrections clean and tight (50% chose this)
  • All of the above (50% chose this)
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Characteristic of a square law type of vacuum tube detector:
  • High sensitivity is provided due to the audio output signal amplitude being proportioned to the square of the radio frequency voltage (20% chose this)
  • High percentage of second harmonic distortion (0% chose this)
  • Works on weak signals only (0% chose this)
  • All of the above (80% chose this)
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Theoretical gain of a tube. The ratio of a small change in plate voltage to give a certain small change in plate current to a change in grid which would cause the same current:
  • Amplification factor (25% chose this)
  • Power factor (25% chose this)
  • Maximum inverse plate voltage (50% chose this)
  • None of the above (0% chose this)
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Occurs when plate current equals electron emission for any given filament or cathode temperature:
  • Plate saturation (40% chose this)
  • Electron saturation (20% chose this)
  • Filament saturation (20% chose this)
  • None of the above (20% chose this)
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Minimizes transfer of harmonic frequencies between two inductively coupled circuits:
  • ***<This answer left blank by the FCC> (17% chose this)
  • Induces magnetic shielding between two coils (33% chose this)
  • Transfers energy between two coils (33% chose this)
  • None of the above (17% chose this)
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An 18 ohm and a 15 ohm resistor are connected in parallel; a 36 ohm resistor is connected in series with this combination; a 22 ohm resistor is connected in parallel with this total combination. The total current is 5 A. What current is flowing in the 15 ohm resistor?
  • 0.908 A (40% chose this)
  • 1.000 A (40% chose this)
  • 1.908 A (0% chose this)
  • 0.809 A (20% chose this)
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Low sensitivity of a 3 circuit regenerative receiver might be caused by:
  • Faulty tube (0% chose this)
  • Out of phase feedback (0% chose this)
  • Insufficient feedback (33% chose this)
  • All of the above (67% chose this)
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Materials which can be used as crystal detectors:
  • Silicon, galena (33% chose this)
  • Carborundum, iron pyrites (17% chose this)
  • Silicon, iron pyrites (0% chose this)
  • All of the above (50% chose this)
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How may low impedance (75 ohm) head telephones be connected to the output of a vacuum tube?
  • By using an impedance matching transformer in the output stage (20% chose this)
  • Connect them as a cathode bias resistor in the output stage (20% chose this)
  • Either A or B (60% chose this)
  • None of the above (0% chose this)
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An EMF may be generated by sound waves by what principle?
  • Electrostatic (0% chose this)
  • Piezo-electric (33% chose this)
  • Resistance change (0% chose this)
  • All of the above (67% chose this)
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The speed of an induction motor is determined:
  • By the number of pairs of poles (0% chose this)
  • By the line frequency (14% chose this)
  • By the load (43% chose this)
  • All of the above (43% chose this)
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During what periods must a distress message be repeated following the initial transmission?
  • Until an answer is received, especially during the silent periods (20% chose this)
  • Must repeated every 15 minutes (40% chose this)
  • Must be repeated every 5 minutes (20% chose this)
  • Must be repeated every 3 minutes (20% chose this)
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The ratios of primary and secondary currents in a power transformer:
  • Are approximately in inverse ratio to the turns ratio (0% chose this)
  • Is to some extent affected by the diameter of the primary and secondary wire (0% chose this)
  • The current ratio is in inverse proportion to the voltage ratio (0% chose this)
  • All of the above (100% chose this)
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For protection of personnel handling a transmitter:
  • Ground all exposed metal parts (60% chose this)
  • Transmitter is equipped to shunt grounded faults (20% chose this)
  • Discontinue operating on high power (0% chose this)
  • None of the above (20% chose this)
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What is the total impedance of a series AC circuit having a resistance of 6 ohms, an inductive reactance of 17 ohms, and zero capacitive reactance?
  • 15 ohms (14% chose this)
  • 27 ohms (14% chose this)
  • 18 ohms (57% chose this)
  • 5 ohms (14% chose this)
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Some components of a three-circuit regenerative circuit tested in troubleshooting:
  • All tubes, power supply voltage, continuity of coils (13% chose this)
  • Proper contacting of each position of tapped switches, pigtail connections, shorted variable capacitor (0% chose this)
  • Grid leak for open circuit, grid capacitor for short, audio transformer for continuity, jacks & cords, antenna and ground connections (13% chose this)
  • All of the above (75% chose this)
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The unit of conductance is:
  • Ohm (17% chose this)
  • Mho (67% chose this)
  • Henry (0% chose this)
  • Ampere (17% chose this)
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The best suited material for use as an antenna strain insulator exposed to the elements:
  • Glazed porcelain (17% chose this)
  • Glass (17% chose this)
  • Graphite composite (0% chose this)
  • Rubber (67% chose this)
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Why is the clock on a compulsorily equipped ship radiotelegraph station required to have a sweep second hand?
  • To be able to accurately time the spaces and dashes of the auto-alarm system (0% chose this)
  • To accurately time the silent periods (0% chose this)
  • Both A & B (80% chose this)
  • None of the above (20% chose this)
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To provide additional feedback voltage in a crystal oscillator what is sometimes needed?
  • An additional plate grid feedback capacitor (33% chose this)
  • Adding a coupling circuit in series with the plate resistors (50% chose this)
  • An astable multivibrator (0% chose this)
  • A monostable multivibrator (17% chose this)
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What is the purpose of blinking in a loran navigational system?
  • To warn the receiving operator that difficulty exists at the transmitting stations? (50% chose this)
  • To warn the operator that the system is in use (33% chose this)
  • The loran system needs to be aligned (0% chose this)
  • None of the above (17% chose this)
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What is meant by the term polarization of a radio wave?
  • Electromagnetic waves penetrate conductors because of eddy currents (0% chose this)
  • Electromagnetically charged waves cross the zero axis in perpendicular patterns causing polarization to appear (25% chose this)
  • The polarization of a radio wave is determined by the direction of the electromagnetic wave plane (75% chose this)
  • The polarization of a radio wave is determined by the direction of the magnetic wave plane (0% chose this)
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What is the line current of a 7 HP motor operating on 120 V at full load, a power factor of 0.8, and 95% efficiency?
  • 56 A (33% chose this)
  • 57.2 A (67% chose this)
  • 58 A (0% chose this)
  • None of the above (0% chose this)
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Which operator is authorized to make equipment adjustments at maritime radio stations which may affect transmitter operation?
  • The holder of a marine radio operator permit or higher class license (14% chose this)
  • The holder of a restricted radiotelephone operator permit when the radiated power is less than 100 watts (0% chose this)
  • Only the holders of a first or second class radiotelegraph of the general radiotelephone operator's license (71% chose this)
  • The holder of a GMDSS radio operator or higher class radiotelephone license (14% chose this)
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Why should the case of a high-voltage transformer be grounded?
  • To protect personnel handling the equipment from shock (0% chose this)
  • To prevent high static voltages building up between the case and grounds (33% chose this)
  • A & B (67% chose this)
  • None of the above (0% chose this)
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Electrolyte capacitors are desirable over other types because:
  • A large capacitance may be obtained with small physical dimensions (33% chose this)
  • They have a cathode (0% chose this)
  • The wet-type electrolytic capacitor is "self-healing" (0% chose this)
  • A & C (67% chose this)
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In order of selectivity, the best receivers are:
  • Superheterodyne, tuned radio frequency, superregenerative (17% chose this)
  • Tuned radio-frequency, superheterodyne, superregenerative (0% chose this)
  • Superregenerative, tuned radio-frequency, superheterodyne (67% chose this)
  • Tuned radio frequency, superregenerative, superheterodyne (17% chose this)
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From how many simultaneous directions is a direction finder capable of receiving signals if adjusted to take unilateral bearings through 360 degrees?
  • From 360 degrees (0% chose this)
  • From 180 degrees (0% chose this)
  • From all but one direction (80% chose this)
  • None of the above (20% chose this)
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Sulfation:
  • Reduces terminal voltage (0% chose this)
  • Increases internal resistance (14% chose this)
  • Reduces power output (14% chose this)
  • All of the above (71% chose this)
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A material flashed by the application of heat after the tube is evacuated that absorbs any gases remaining inside the tube:
  • Space charge (17% chose this)
  • Getter (17% chose this)
  • Collector (17% chose this)
  • Emitter (50% chose this)
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How may the Q of a parallel resonant circuit be increased?
  • Increasing coupling to the resonant circuit (0% chose this)
  • Using coil and capacitor supports of special low - loss materials (17% chose this)
  • Both A and B (83% chose this)
  • Decreasing coupling to the resonant circuit (0% chose this)
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Local action in a lead-acid storage cell:
  • Causes a slow discharge in the cell (0% chose this)
  • Forms a very hard sulfate on the plates (17% chose this)
  • May be reduced by trickle charging when the battery is not in actual use (17% chose this)
  • All of the above (67% chose this)
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An incoming signal causing image interference is ____ the IF above or below the frequency to which the receiver is tuned:
  • Twice (33% chose this)
  • Three times (17% chose this)
  • Half of (50% chose this)
  • Three quarters of (0% chose this)
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By what factor must the voltage of an AC circuit, as indicated on the scale of an AC voltmeter, be multiplied to obtain the peak value?
  • The multiplying factor is .414 (20% chose this)
  • The multiplying factor is A.414 (60% chose this)
  • The multiplying factor is A.114 (20% chose this)
  • The multiplying factor is A.141 (0% chose this)
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If the vacuum tube heater in an approved auto-alarm system burns out:
  • A pair of contacts close and energize the bell relay (20% chose this)
  • A pair on contacts open and energize the ball relay (40% chose this)
  • A pair of contacts close and de-energize the bell relay (20% chose this)
  • A pair of contacts open and deenergize the bell relay (20% chose this)
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Does an AC ammeter indicate peak, average, or effective values of current?
  • The conventional AC ammeter is calibrated to indicate effective (TRM) values of current (0% chose this)
  • The conventional AC ammeter is calibrated to indicate effective (RMS) values of current (75% chose this)
  • An AC ammeter indicates peak values of current (25% chose this)
  • An AC ammeter indicates average values of current (0% chose this)
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The direction of electron flow through a coil and the manner of winding the turns:
  • Influence the direction of magnetic line of force generated by an electromagnet (33% chose this)
  • Are determined by the left-hand status rule (17% chose this)
  • Are determined by the diameter of the wire and length (0% chose this)
  • Both A and C (50% chose this)
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A positive temperature coefficient means:
  • Resistance increases as the temperature increases (20% chose this)
  • Resistance decreases as the temperature decreases (20% chose this)
  • Both A & B (60% chose this)
  • None of the above (0% chose this)
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The diode detector:
  • Is square law on weak signals (0% chose this)
  • Is practically linear on strong signals (0% chose this)
  • Is square law on strong signals (0% chose this)
  • A & B (100% chose this)
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What is the purpose of an auto-alarm signal keying device on a compulsorily equipped ship?
  • To automatically produce Morse code (0% chose this)
  • To automatically send an SOS signal (14% chose this)
  • To automatically produce the correct auto-alarm signal (86% chose this)
  • None of the above (0% chose this)
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Ohm's law for AC circuits when I = amperes, E = volts, Z = impedance in volts is:
  • I = E/Z (17% chose this)
  • E = IZ (17% chose this)
  • Z= Z/I (17% chose this)
  • All of the above (50% chose this)
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Vacuum tubes operating as Class A amplifiers may be used as:
  • Audio power amplifiers, audio voltage amplifiers, microphones amplifiers, line amplifiers (0% chose this)
  • Oscilloscope amplifiers, modulators (14% chose this)
  • Phonograph amplifiers (14% chose this)
  • All of the above (71% chose this)
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The total reactance when two capacitances of equal value are connected in series is:
  • The product of the two individual reactances in ohms (20% chose this)
  • The sum of the two individual reactances in ohms (80% chose this)
  • The difference of the two individual reactances in ohms (0% chose this)
  • None of the above (0% chose this)
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An advantage of link coupling between RF amplifier stages is:
  • The flexibility of mechanical construction possible (0% chose this)
  • Reduction of tube capacitance effects on the L/C ratio of the tank circuits (0% chose this)
  • Both A and B (83% chose this)
  • Neither A or B (17% chose this)
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How does a First Class Radiotelegraph Operator renew an unexpired license?
  • Renewal document indicating license serial number must be forwarded to the FCC during the last 90 days of the license term (38% chose this)
  • Application is made to the nearest Commercial Operator Licensing Examination Manager (COLEM) during the final six months of the license term (13% chose this)
  • By submitting Form 756, current license copy, and appropriate fee to the FCC during the last year of the five year license term (38% chose this)
  • A current Radio telegraphy Proficiency Testimonial (RPT) obtained from the ship's master must be attached to the renewal application Form 739 (13% chose this)
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The needle of a magnetic compass when placed within a coil carrying an electric current:
  • Will tend to become parallel with the axis of the coil (0% chose this)
  • Will point to the north pole end of the coil (20% chose this)
  • Will point to the south pole end of the coil (0% chose this)
  • A & B (80% chose this)
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The advantage of using iron cores of special construction in RF transformers and inductance?
  • Increase of Q and gain of circuits using such cores (0% chose this)
  • Increase of selectivity and gain of circuits using such cores (33% chose this)
  • Increase of Q and selectivity (17% chose this)
  • All of the above (50% chose this)
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A separate source of power is sometimes desirable for crystal-oscillator units in a transmitter:
  • To prevent dynamic instability of the crystal oscillator (40% chose this)
  • To prevent thermocoupling of the crystal oscillator (20% chose this)
  • To prevent overtuning of the crystal oscillator (20% chose this)
  • To cause dynamic instability of the crystal oscillator (20% chose this)
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Adding an inductor in series with an antenna will have what effect on the resonant frequency?
  • Decrease (33% chose this)
  • Increase (56% chose this)
  • Neutralization (0% chose this)
  • Equalization (11% chose this)
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Which type of amplifier circuit is used in a link coupling R-F?
  • Push-push (0% chose this)
  • Push-pull (40% chose this)
  • Phase splitter (20% chose this)
  • FM discriminator (40% chose this)
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Distortion in a Class A amplifier can be caused by:
  • Insufficient plate and screen potentials, incorrect grid bias defective rube (0% chose this)
  • Leaky or shorted input coupling capacitor (20% chose this)
  • Excessive anokutyde if grid signal, incorrect value of load impedance (20% chose this)
  • All of the above (60% chose this)
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The principal function of the filter in a power supply:
  • To remove the variations in amplitude of the rectifier output (0% chose this)
  • To provide a relatively unvarying DC voltage for use in the various circuits (17% chose this)
  • Either A or B (83% chose this)
  • None of the above (0% chose this)
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What is the total power dissipation capability of two 10 watt 500 ohm resistors connected in parallel?
  • 20 watts (67% chose this)
  • 40 watts (0% chose this)
  • 5 watts (33% chose this)
  • None of the above (0% chose this)
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On shipboard what factors may effect the accuracy of a direction finder after it has been properly installed, calibrated?
  • A received wave which has been bent by night effect (0% chose this)
  • By any changing of the position of nearby metallic objects (33% chose this)
  • Both A & B (67% chose this)
  • None of the above (0% chose this)
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The formation of hydrogen gas around the positive electrode of a primary cell is:
  • Depolarization (0% chose this)
  • Polarization (33% chose this)
  • Manganese dioxide (17% chose this)
  • None of the above (50% chose this)
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Crystal surfaces should be free of dirt of grease to operate properly:
  • Do not touch the faces of the crystal with the fingers (17% chose this)
  • Clean the faces with soap and water (0% chose this)
  • Clean the faces with carbon tetrachloride (0% chose this)
  • All of the above (83% chose this)
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Disadvantages of a stage of RF amplification are:
  • A power audio amplifier would be needed to operate a loudspeaker (0% chose this)
  • An RF amplifier requires additional tuned circuits and tuning elements (50% chose this)
  • Shielding will probably be necessary (0% chose this)
  • All of the above (50% chose this)
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On an average yearly basis the received Trans-Atlantic signals increased in strength in proportion to the degree of ____. Made on the basis of the 11 year cycle:
  • Sun spot activity (80% chose this)
  • Aurora borealis (20% chose this)
  • Extratropical Advection (0% chose this)
  • Perigean tide (0% chose this)
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What turns ratio does a transformer need to match a source impedance of 500 ohms to a load of 10 ohms?
  • 7.1 to 1 (60% chose this)
  • 7 to 1 (20% chose this)
  • 14 to 1 (20% chose this)
  • None of the above (0% chose this)
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Abnormally low input power terminal voltage of a lifeboat radiotelegraph transmitter while in operation could be caused by:
  • Reversed polarity (0% chose this)
  • Excessive overload (20% chose this)
  • A partially discharged battery (0% chose this)
  • B & C (80% chose this)
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What should the plate current do in the operation of a Class B audio amplifier?
  • Fluctuate (20% chose this)
  • Remain Steady (60% chose this)
  • Increase (20% chose this)
  • None of the above (0% chose this)
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The positive plate of a lead-acid storage cell:
  • Is composed of pure spongy lead (25% chose this)
  • Is composed of lead peroxide (0% chose this)
  • Is composed of a compound of pure spongy lead and lead peroxide (0% chose this)
  • None of the above (75% chose this)
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What is the primary reason for the use of a crystal controlled oscillator for use as a transmitter?
  • No cross-modulation (0% chose this)
  • Increase in gain (17% chose this)
  • Frequency stability (67% chose this)
  • Impedance gain and wider bandpass (17% chose this)
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The ____ of a DC motor periodically change the armature coils to maintain one direction of rotation:
  • Field coils (50% chose this)
  • Connector (17% chose this)
  • Brushes (17% chose this)
  • Auxiliary speed control (17% chose this)
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A tube containing either a filament or cathode structure, grid, and a plate is a:
  • Triode (60% chose this)
  • Tetrode (0% chose this)
  • Pentode (20% chose this)
  • Diode (20% chose this)
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What are the lowest frequencies used in radio communication today?
  • SSB voice (8% chose this)
  • Double-sideband FM voice (8% chose this)
  • 15 kHz (31% chose this)
  • 1 kHz to 5 kHz (54% chose this)
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If the output frequency after passing through three doubler stages is 16,800 kHz, give the crystal frequency of a transmitter:
  • 2160 kHz (17% chose this)
  • 2 GHz (17% chose this)
  • 2110 kHz (50% chose this)
  • 2 kHz (17% chose this)
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You may measure the voltage of a battery under heavy load:
  • To determine its condition of charge (80% chose this)
  • To determine its polarity (20% chose this)
  • To determine its age (0% chose this)
  • None of the above (0% chose this)
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The total inductance of two coils in series without any mutual coupling is:
  • The sum of the individual inductances (20% chose this)
  • The product of the individual inductances divided by their sum (80% chose this)
  • Infinite (0% chose this)
  • None of the above (0% chose this)
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For how long a period of continuous operation should the emergency power supply of a compulsorily equipped ship station be capable of energizing the emergency radiotelegraph installation?
  • At least 6 consecutive hours (20% chose this)
  • At least 12 hours (20% chose this)
  • At least 24 consecutive hours (40% chose this)
  • At least 48 consecutive hours (20% chose this)
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The velocity of propagation of radio frequency waves in free space is:
  • 300,000 meters / second (0% chose this)
  • 186,284 miles / second (20% chose this)
  • The same as the velocity of light in free space (40% chose this)
  • All of the above (40% chose this)
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Causes of motor-generator bearing overheating include:
  • Incorrect kind of lubrication, lack of ventilation (0% chose this)
  • Constant overload, dirt in bearings (13% chose this)
  • Misalignment (0% chose this)
  • All of the above (88% chose this)
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Types of transistors:
  • Point-contact (17% chose this)
  • Junction (17% chose this)
  • Both A & B (33% chose this)
  • NPP (33% chose this)
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Advantages of a stage of RF amplification are:
  • Improved sensitivity, improved signal-to-noise ratio (0% chose this)
  • Improved selectivity, improved signal-to-noise ratio (17% chose this)
  • Improved signal-to-noise ratio, more efficient and more stable operation of the detector (17% chose this)
  • All of the above (67% chose this)
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The cathode of an indirectly heated type of vacuum tube should be maintained at nearly the same potential as the heater circuit:
  • To reduce hum pickup into the cathode (0% chose this)
  • To prevent breakdown of the insulation between the heater and cathode (25% chose this)
  • A & B (50% chose this)
  • None of the above (25% chose this)
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What factors determine the heat generated in a conductor?
  • It is directly proportional to the resistance (0% chose this)
  • It is directly proportional to the square of the current (17% chose this)
  • Both A & B (67% chose this)
  • None of the above (17% chose this)
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Shielding an RF inductance:
  • Increases the losses of the inductance (0% chose this)
  • Lowers the inductance value and the Q (33% chose this)
  • Increases the coil capacity to the shield (0% chose this)
  • All of the above (67% chose this)
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What is the effect of low temperature on the operation of a lead-acid storage battery?
  • Electrolyte may freeze and split the battery if sg too low (0% chose this)
  • The capacity is decreased (0% chose this)
  • A & B (100% chose this)
  • None of the above (0% chose this)
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What is the purpose of a shunt as used with an ammeter?
  • To permit a decrease in the indicating range of the meter (0% chose this)
  • To permit an increase in the indicating range of the meter which is almost inversely proportional to the resistance of the shunt (60% chose this)
  • A shunt should not be used with a ammeter (0% chose this)
  • None of the above (40% chose this)
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When a tube is used as a Class B amplifier what portion of the excitation voltage cycle does plate current flow?
  • Slightly more than 180 degrees (40% chose this)
  • Slightly less than 180 degrees (0% chose this)
  • 360 degrees (20% chose this)
  • None of the above (40% chose this)
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How can you correct power factor in an electrical circuit?
  • Inductance is used to correct a leading angle (0% chose this)
  • Capacitance is used to correct a lagging angle (0% chose this)
  • Neither A or B (14% chose this)
  • Both A and B (86% chose this)
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The approximate efficiency of a Class C vacuum tube amplifier:
  • 20%-30% (17% chose this)
  • 60% (17% chose this)
  • 85% (67% chose this)
  • 100% (0% chose this)
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For how long must mobile stations listen after hearing an urgency signal?
  • For at least 5 minutes (0% chose this)
  • For at least 30 minutes (40% chose this)
  • For at least 3 minutes (40% chose this)
  • None of the above (20% chose this)
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What is the order of priority of radiotelegraph communications in the maritime services?
  • Alarm, radio-direction finding, and health and welfare communications (0% chose this)
  • Navigation hazards, meteorological warnings, priority traffic (60% chose this)
  • Distress calls, and signals, followed by communications preceded by urgency and safety signals (40% chose this)
  • Government precedence, messages concerning safety of life and protection of property and traffic concerning grave imminent danger (0% chose this)
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Are there any age requirements that a person must meet before he can be issued a radiotelegraph operator license?
  • At least 18 years of age for a second class license (33% chose this)
  • At least 21 years of age for a first class license (0% chose this)
  • Persons under 21 now holding a radiotelegraph first class license may renew same without regard to age requirement (0% chose this)
  • All of the above (67% chose this)
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A dry cell may be tested:
  • Must be tested under normal load condition (0% chose this)
  • May be tested under no load condition (0% chose this)
  • May be taken by any conventional voltmeter (0% chose this)
  • A & C (100% chose this)
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What is the main advantage obtained by using two triodes in push-pull in a Class a audio frequency amplifier?
  • Increased power output (0% chose this)
  • Cancellation of even harmonic distortion in the output (0% chose this)
  • Elimination of DC saturation, elimination of cathode by-pass capacitor (20% chose this)
  • All of the above (80% chose this)
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In the usual type dry cell:
  • The negative electrode is made of zinc (0% chose this)
  • The positive electrode is made of carbon (20% chose this)
  • The negative electrode is made of zinc (0% chose this)
  • A & B (80% chose this)
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What are the three factors to consider when figuring the surge impedance of a non-resonant transmission line?
  • Diameter of the conductor, space between conductors, dielectric constant of insulating material (67% chose this)
  • Voltage on RF line, diameter of conductors, space between dielectric (0% chose this)
  • Diameter of shielding, space between dielectric constant, insulating shield around the conductor (33% chose this)
  • None of the above (0% chose this)
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The unit of capacitance is:
  • Farad (17% chose this)
  • Microfarad (17% chose this)
  • Coulomb (33% chose this)
  • A & B (33% chose this)
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The degree of coupling is varied in a pi-network used to transfer energy from a vacuum tube plate circuit to an antenna:
  • By adjusting the series capacitors (0% chose this)
  • By adjusting the tank capacitors (25% chose this)
  • By changing the plate voltage (50% chose this)
  • None of the above (25% chose this)
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How often must a radiotelegraph station transmit its call sign when a transmission is maintained for more than 20 minutes in the band 405-525 kHz?
  • At 20 minute intervals (0% chose this)
  • At least every 10 minutes (40% chose this)
  • At 15 minute intervals unless public correspondence is in progress (40% chose this)
  • At the beginning and end of each communication with any other station (20% chose this)
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An RF filter in the plate circuit of a tube detector is sometimes necessary to:
  • Prevent RF variations from affecting the following audio stages (14% chose this)
  • Alter the impedance of the detector load circuit (14% chose this)
  • Insert RF variations from affecting the audio stages (0% chose this)
  • To prevent RF variations from affecting the following RF stages (71% chose this)
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What form of energy is stored in a lead-acid storage battery?
  • Chemical (100% chose this)
  • Mechanical (0% chose this)
  • Heat (0% chose this)
  • Light (0% chose this)
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The positive plate of an Edison-type storage cell is:
  • Finely powdered pure iron (33% chose this)
  • Green oxide of nickel (17% chose this)
  • Lithium oxide (17% chose this)
  • None of the above (33% chose this)
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What factors determine the no-load voltage ratio of a power transformer?
  • Power ratio (0% chose this)
  • Turns ratio (25% chose this)
  • Voltage ratio (25% chose this)
  • Power factor (50% chose this)
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When free electrons in a conductor acquire sufficient energy to leave the conductor and pass into the surrounding space, it is expressed as:
  • Secondary emission (20% chose this)
  • Electron emission (40% chose this)
  • Primary electron release (40% chose this)
  • None of the above (0% chose this)
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The suppressor grid in a multielement vacuum tube:
  • Is highly negative with respect to the plate (11% chose this)
  • Returns secondary electrons to the plate (11% chose this)
  • Increases the permissible gain and the efficiency of the tube (22% chose this)
  • All of the above (56% chose this)
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The factor by which the product of volts and amperes must be multiplied to obtain true power is:
  • Power factor (50% chose this)
  • Apparent power (50% chose this)
  • Phase angle (0% chose this)
  • None of the above (0% chose this)
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An auxiliary receiving antenna on a ship with a radio direction finder:
  • Is mainly a spare antenna (17% chose this)
  • Enables the radio operator to maintain watch on 500 kHz whether or not the direction finder is in use (50% chose this)
  • Enables the radio operator to use the direction finder whether or not the communications receiver is in use (33% chose this)
  • None of the above (0% chose this)
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In a radiotelegraph transmitter with a DC generator plate voltage source, an AC generator filament supply, and grid-bias keying, what could be wrong when the emission continues with the key contacts open?
  • Insufficient grid blocking bias is applied to the grid when the key is open (0% chose this)
  • Shorted bias resistor (0% chose this)
  • Shorted key-click filter (0% chose this)
  • All of the above (100% chose this)
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Electrical resistance is measured with:
  • An ohmmeter (83% chose this)
  • A wattmeter (0% chose this)
  • An Ammeter (0% chose this)
  • A voltmeter (17% chose this)
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What is a self rectified circuit?
  • Provides a tone frequency for F3F emissions (0% chose this)
  • An op-amp circuit that provides a feed-back to the input (75% chose this)
  • Provides a tone frequency for A-2 emissions (25% chose this)
  • A self oscillating frequency discriminator circuit (0% chose this)
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Shock excitation into an L-C circuit is the result of:
  • A voltage being momentarily introduced (0% chose this)
  • The capacitor may be charged (0% chose this)
  • The inductor may have a voltage induced (20% chose this)
  • All of the above (80% chose this)
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Factors which determine the amplitude of the voltage induced in a conductor which is cutting magnetic lines of force:
  • Flux density (0% chose this)
  • Velocity that the conductor cuts the magnetic lines of force (0% chose this)
  • The angle at which the conductor cuts through the magnetic lines of force (0% chose this)
  • All of the above (100% chose this)
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Factors which determine bios voltage of a vacuum tube:
  • Class of operation, plate supply voltage, permissible distortion (0% chose this)
  • Grid signal magnitude, permissible plate dissipation, desired amplification factor (0% chose this)
  • The no-signal plate current desired, the desirability of drawing grid current (25% chose this)
  • All of the above (75% chose this)
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What may be observed as the antenna circuit is brought into resonance about the plate current of the final amplifier?
  • It will increase (83% chose this)
  • It will decrease (17% chose this)
  • It will remain constant (0% chose this)
  • None of the above (0% chose this)
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A form of regenerative receiver in which the detector breaks into and out of oscillation at a rate above audibility:
  • Superregenerative receiver (25% chose this)
  • Superheterodyne receiver (25% chose this)
  • Discriminator receiver (0% chose this)
  • Detuned radio frequency receiver (50% chose this)
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If a 500 Hz transformer is connected to a 60 Hz source of the same voltage:
  • The primary would draw excessive current (20% chose this)
  • The transformer would overheat (0% chose this)
  • The primary might burn out (20% chose this)
  • All of the above (60% chose this)
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A tungsten filament is operated at ____ temperature than a thoriated tungsten filament:
  • A higher (57% chose this)
  • A lower (29% chose this)
  • The same (14% chose this)
  • Unknown (0% chose this)
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The formula for determining the resonant frequency of a circuit when the inductance and capacitance are known is:
  • f = 1/(2 pi times the square root of LC) (0% chose this)
  • f = 0.159/(the square root of LC) (0% chose this)
  • Both A & B (100% chose this)
  • None of the above (0% chose this)
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If signals are heard with headphones in the detector plate circuit of a receiver, but none are heard with headphones in the first AF stage plate circuit, what might be the cause?
  • Open winding of the coupling transformer (0% chose this)
  • Defective coupling capacitor, improper operating potentials (0% chose this)
  • Defective tube (0% chose this)
  • All of the above (100% chose this)
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What class of amplifier is used as linear in order not to distort the modulation components?
  • Class A (75% chose this)
  • Class B (0% chose this)
  • Class C (0% chose this)
  • None of the above (25% chose this)
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The gain of a triode audio amplifier is a function of:
  • Tube transconduction (0% chose this)
  • Plate load impedance (0% chose this)
  • Transformer step-up (if used) (0% chose this)
  • All of the above (100% chose this)
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Radio equipment on which electrolyte may be used:
  • Electrolyte capacitor (0% chose this)
  • Electrolyte rectifier (0% chose this)
  • Electrolyte detector (0% chose this)
  • All of the above (100% chose this)
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How would you adjust a regenerative receiver without RF amplifier stages to receive radiotelegraph signals through interference?
  • Provide the maximum selectivity and gain at the incoming signal frequency (20% chose this)
  • Increase the degree of coupling between the antenna and grid coils (0% chose this)
  • Provide the minimum possible regeneration (60% chose this)
  • None of the above (20% chose this)
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If the velocity of a radio wave is 186,000 statute miles per second, how many nautical miles does a radar pulse travel in one microsecond?
  • 0.1614 nautical miles (14% chose this)
  • 11614 nautical miles (43% chose this)
  • 0.2014 nautical miles (29% chose this)
  • 2200 nautical miles (14% chose this)
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By reducing the physical length of a Hertzian antenna what are the results?
  • The resonant frequency will be reduced (43% chose this)
  • The signal on a nearby frequency will be saturated upon modulation (14% chose this)
  • The antenna trap is reduced causing cross modulation (0% chose this)
  • The resonant frequency will increase (43% chose this)
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Unused portions of inductances in receivers are ____ to reduce any losses that might occur in these unused windings:
  • Shorted (57% chose this)
  • Removed from the circuit (29% chose this)
  • Insulated (0% chose this)
  • Straightened out (14% chose this)
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A superheterodyne receiver is adjusted to 2738 kHz. The IF is 475 kHz. What is the grid circuit of the second detector tuned to?
  • 475 kHz (0% chose this)
  • 950 kHz (67% chose this)
  • 2263 kHz (0% chose this)
  • 3213 kHz (33% chose this)
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A capacitor's charge is stored:
  • Upon the inner surface of the capacitor plates (0% chose this)
  • As an electrostatic field which exists in the space between the plates (33% chose this)
  • A & B (67% chose this)
  • None of the above (0% chose this)
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Your emergency battery has a specific gravity reading of 1.120. What should be done?
  • Place the battery on charge at once (0% chose this)
  • Bring the electrolyte level to about 1/4 inch above the top of the plates (25% chose this)
  • The battery will be fully charged when the specific gravity reads 1.280 to 1.300 (25% chose this)
  • All of the above (50% chose this)
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In an AC circuit, a series inductance acting alone:
  • Causes the current to lag the applied voltage by 90 degrees (17% chose this)
  • Causes the current to lead the applied voltage by 90 degrees (67% chose this)
  • Causes the current to lag the applied voltage by 45 degrees (17% chose this)
  • Causes the current to lead the applied voltage by 45 degrees (0% chose this)
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Factors which influence the resistance of a conductor:
  • Cross-sectional area (0% chose this)
  • Length (0% chose this)
  • Temperature (0% chose this)
  • All of the above (100% chose this)
Click here to add explanation
Ship's power is generated as 3-phase and is ungrounded. On a delta-wound transformer with 120 VAC line-to-line secondary, what is the voltmeter reading from line to ground:
  • Approx 67 volts for a normal balanced system with no faults (0% chose this)
  • 0 VAC for a system with that phase faulted to ground (29% chose this)
  • 120 VAC when another phase is faulted to ground (29% chose this)
  • Any of the above (43% chose this)
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The ratio of the frequencies of the output and input circuits of a single-phase full-wave rectifier:
  • 1 to 1 (60% chose this)
  • 2 to 1 (40% chose this)
  • 1 to 2 (0% chose this)
  • None of the above (0% chose this)
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How does an applicant qualify for a Third Class Radiotelegraph Operator's Certificate?
  • By passing the appropriate written examinations and receiving by ear code groups and plain text for a period of one minute without error at the appropriate speed (0% chose this)
  • Applicant must send and receive radiotelegraphy at the prescribed speed and be at least 21 years old (33% chose this)
  • By the successful completion of radiotelegraphy Elements 1 and 2 plus written examinations on radio law, telegraphy practices and transmitter maintenance (50% chose this)
  • By passing a written examination on radio law, electronic fundamentals and radiotelegraph practices plus a telegraphy receiving examination (17% chose this)
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Transmitters that employ variometers rather than variable capacitors as tuning elements do so because of:
  • The size of required variable capacitors in the medium frequency band (0% chose this)
  • There is no such thing as a variometer! (33% chose this)
  • Variometers can be relatively compact (33% chose this)
  • A & C (33% chose this)
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How would you reduce or eliminate broadcast signal interference of reception on 500 kHz?
  • Use a regenerative receiver without RF amplifier stages (0% chose this)
  • Use a suitable wavetrap resonated to reject the undesired signals (67% chose this)
  • Use a crystal detector receiver tuned to the exact frequency (17% chose this)
  • None of the above (17% chose this)
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What would be the antenna current when a transmitter has an antenna current of 8 amp, under A -1, even if it is 100% modulated by sinusoidal modulation?
  • 9.8 amp (0% chose this)
  • The antenna current will increase by 22.5% (20% chose this)
  • Either A or B (80% chose this)
  • None of the above (0% chose this)
Click here to add explanation
A quartz crystal in a radio transmitter:
  • Is used to provide a high degree of master-oscillator frequency stability (0% chose this)
  • May be the sole tuned circuit in the oscillator (40% chose this)
  • A & B (60% chose this)
  • None of the above (0% chose this)
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To operate on a lower resonant frequency on an available Marconi antenna which would be the correct procedure?
  • Add a capacitor in series with the antenna (25% chose this)
  • Add an inductor in series with the antenna (50% chose this)
  • Add a screen grid bypass capacitor parallel to the antenna trap (0% chose this)
  • Add an RF choke across the feed line to ground (25% chose this)
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In what part of the RF spectrum do marine radar systems operate?
  • In the order of 10,000 MHz or 3000 MHz (20% chose this)
  • Wavelength of 3 cm or 10 cm (20% chose this)
  • Both A & B (60% chose this)
  • None of the above (0% chose this)
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What is the license term of the First Class Radiotelegraph Operator License?
  • The license is valid for the lifetime of the holder (0% chose this)
  • A license is valid for a period of ten years form the DOI (date of issuance) (0% chose this)
  • The five year term license is renewable by retaking updated exam Elements 1 and 3 during the last 90 days before expiration (25% chose this)
  • The license term is five years and may be renewed indefinitely without retesting (75% chose this)
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The approximate efficiency of a Class B vacuum tube amplifier:
  • 20%-30% (20% chose this)
  • 60% (40% chose this)
  • 85% (40% chose this)
  • 100% (0% chose this)
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What might be the cause of a positive shift in carrier amplitude during modulation?
  • Parasitic oscillations, excessive audio drive (0% chose this)
  • Incorrect tuning of final amplifier (0% chose this)
  • Insufficient RF excitation, incorrect neutralization (20% chose this)
  • All of the above (80% chose this)
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To prevent corrosion of battery terminals:
  • Occasionally clean and coat them with Vaseline or other suitable lubricants (50% chose this)
  • Use only brass terminals (33% chose this)
  • Use only stainless steel terminals (17% chose this)
  • Keep battery on trickles charge (0% chose this)
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A master-oscillator power-amplifier transmitter has been operating normally. The antenna ammeter suddenly reads zero. All filaments are burning and plate and grid meters read normal currents and voltages. What happened?
  • A shorted antenna ammeter (0% chose this)
  • An open connection in the remote reading meter (0% chose this)
  • Both a and b (60% chose this)
  • None of the above (40% chose this)
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A station has an assigned frequency of 8000 kHz and a frequency tolerance of plus or minus 0.04%. The oscillator operates at 1/8th of the input. What is the maximum permitted deviation of the oscillation frequency in Hz, which will not exceed the tolerance?
  • Plus or minus 400 Hz (33% chose this)
  • Plus or minus 320 Hz (33% chose this)
  • Plus or minus 800 Hz (0% chose this)
  • Plus or minus 640 Hz (33% chose this)
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SITOR-ARQ is a common mode of data communications in the maritime service. It is a system based on transmission bursts and acknowledgements. What is the baud, and interval between the burst transmissions:
  • 100 baud, 240 ms interval (0% chose this)
  • 50 baud, 1000 �s interval (25% chose this)
  • 200 baud, 10 ms interval (50% chose this)
  • None of the above (25% chose this)
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When lead-acid cells are subject to low temperatures they should:
  • To prevent freezing (0% chose this)
  • To provide the maximum capacity (20% chose this)
  • A & B (60% chose this)
  • None of the above (20% chose this)
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The most common values of chokes range from:
  • 5 H to 30 H (14% chose this)
  • 30 H-100 H (43% chose this)
  • 1 H to 100 H (29% chose this)
  • 100 H to 1000 H (14% chose this)
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Iron compound cylinders found in inductances:
  • Increase Q (0% chose this)
  • Increase selectivity (29% chose this)
  • Increase gain (14% chose this)
  • All of the above (57% chose this)
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What is the term used when the receiving operator may interrupt the transmitting operator at any point during transmission?
  • Modulation compandering (0% chose this)
  • Interruption shift keying (0% chose this)
  • Break-in operation (67% chose this)
  • Transmission shift keying (33% chose this)
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The disadvantage of using a self-excited oscillator type of transmitter for shipboard service:
  • Frequency instability (57% chose this)
  • Parasitic oscillations (29% chose this)
  • Violent sound intensities (14% chose this)
  • Large capacity (0% chose this)
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Modern reserve transmitters are solid-state designs and transmit using only A2 modulation. When measuring transmitter center frequency, what precaution must be taken:
  • Antenna must be grounded to suppress spurious side-lobes (20% chose this)
  • Modulation must be reduced to zero to eliminate sidebands (60% chose this)
  • Voltage to the PA must be kept at half-value (20% chose this)
  • Antenna current must be reduced to about 2.5 uA (0% chose this)
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Which of the following best explains frequency-shift keying?
  • The shifting of frequencies by modulating the carrier antenna (20% chose this)
  • Changing the frequency of the input when the key is depressed (40% chose this)
  • Changing the frequency of the output when the key is depressed (40% chose this)
  • None of the above (0% chose this)
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Under what condition may an eligible person hold a radiotelegraph operator's license and a Marine Radio Operator permit?
  • When the planned telegraphy operation will occur aboard ship in international waters and another vessel is licensed for operation on the inland waterways (75% chose this)
  • When the commercial radio operator is legally eligible for both foreign and domestic employment (0% chose this)
  • No person may hold any class of radiotelegraph operator's certificate and a Marine Radio Operator Permit (0% chose this)
  • Commercial radiotelegraphers are required to also hold a Marine Radio Operator Permit when the operation occurs on vessels of less than 1600 gross tons (25% chose this)
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The primary function of the power-amplifier stage of a marine radiotelegraph transmitter is:
  • To transmit messages concerning the safety and health of the ship personnel (0% chose this)
  • To transmit messages concerning the weather and safety of upcoming storms (0% chose this)
  • Both A and B (60% chose this)
  • To improve the frequency stability of the oscillator (40% chose this)
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The breakdown voltage rating of a capacitor are determined by:
  • The type of dielectric material used (11% chose this)
  • The thickness of the dielectric material (0% chose this)
  • A & B (78% chose this)
  • None of the above (11% chose this)
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Used to multiply the fundamental frequency by two:
  • Frequency doubler (20% chose this)
  • Harmonic generator with a suitable resonant circuit (0% chose this)
  • A & B (60% chose this)
  • None of the above (20% chose this)
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Given the following vacuum tube constants: Gp = 1000 V, Ip = 150 mA, Ig = 10 mA, Grid leaks = 5000 ohms. What would be the grid bias voltage?
  • 50 V (25% chose this)
  • 100 V (25% chose this)
  • 25 V (13% chose this)
  • None of the above (38% chose this)
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"The temperature coefficient of an x-cut crystal is negative":
  • The operating frequency of the crystal will decrease as the temperature decreases (0% chose this)
  • The operating frequency of the crystal will decrease as the temperature increases (0% chose this)
  • The operating frequency of the crystal will increase as the temperature decreases (25% chose this)
  • B & C (75% chose this)
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Emergency repairs to an inductance coil having burned or charred insulation:
  • Are generally impractical, short of rewinding the coil with good wire (43% chose this)
  • Are always practical if repaired by coating the bad turns with insulating varnish (0% chose this)
  • A & B (57% chose this)
  • None of the above (0% chose this)
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If a vacuum tube in the only RF stages of your receiver burned out, make a temporary repair by:
  • Remove its tube and connect a small (about 0.001 microfarad) capacitor between the control grid and plate connections (0% chose this)
  • Connect the antenna to the control grid of the stage following the one which was burned out (0% chose this)
  • Either A or B (86% chose this)
  • A & B (14% chose this)
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How frequently must an entry be made in a ship radiotelegraph log while a radio watch is being maintained?
  • At least every 15 minutes (0% chose this)
  • This is in addition to the entries referring to silent periods (20% chose this)
  • At least every 30 minutes (0% chose this)
  • Both A & B (80% chose this)
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A series DC motor has:
  • Maximum torque at low speed (0% chose this)
  • Quick starting (0% chose this)
  • Poor speed regulation under varying loads (50% chose this)
  • All of the above (50% chose this)
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If a turn in an inductor is shorted:
  • There will be an decrease of induction (17% chose this)
  • There will be a decrease of Q (17% chose this)
  • There will be overheating with possible burnout (0% chose this)
  • All of the above (67% chose this)
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A diode detector ordinarily produces ____ overall distortion of the audio output wave than does a triode detector:
  • Lower (14% chose this)
  • Higher (14% chose this)
  • Practically the same (29% chose this)
  • Either A or B (43% chose this)
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Amperage may also be known by:
  • Electron flow (0% chose this)
  • Electron drift (0% chose this)
  • Electric current flow (25% chose this)
  • All of the above (75% chose this)
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Contacts which slide together on opening and closing:
  • Are butt joined (0% chose this)
  • Are known as self-wiping (0% chose this)
  • Keep the contacts clean by their action (25% chose this)
  • B & C (75% chose this)
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When used as an RF amplifier, a pentode vacuum tube:
  • Usually does not require neutralization (0% chose this)
  • Usually requires neutralization (20% chose this)
  • May require neutralization at ultra-high frequencies (0% chose this)
  • A & C (80% chose this)
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The purpose of an air gap in a filter choke coil core. Which is the incorrect answer?
  • To decrease the effective inductance for the AC component of current by increasing the DC saturation (0% chose this)
  • To increase the effective inductance for the AC component of current by decreasing the DC saturation (0% chose this)
  • The inductance of the coil in general's decreased (0% chose this)
  • All of the above (100% chose this)
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How often must compulsory radiotelegraph installations on passenger vessels be inspected?
  • When the vessel is placed in service and every 2 years thereafter (0% chose this)
  • At least every 3 years when the ship is within 75 miles of an FCC field office (17% chose this)
  • The ship's master is responsible for completion of the Annual Equipment Verification Report (33% chose this)
  • Equipment inspections are required at least once every 12 months (50% chose this)
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What is the experience requirement of a First Class Radiotelegrapher?
  • The applicant must have been employed as a radio operator on board a United States ship for at least six months (20% chose this)
  • The operator must have held a Second Class Radiotelegraph Operator's Certificate for at least six months (0% chose this)
  • The applicant must have a background of sending or receiving radiotelegraph messages for one year (0% chose this)
  • Both A & B (80% chose this)
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The property of a conductor or coil which causes a voltage to be developed across its terminals when the number of magnetic lines of force in the circuit or coil is changed is:
  • Capacitance (0% chose this)
  • Inductance (40% chose this)
  • Conductance (20% chose this)
  • None of the above (40% chose this)
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Full wave rectification has ____ than half-wave:
  • Better output voltage regulation (14% chose this)
  • Smaller filter components for a given ripple percentage (14% chose this)
  • A and B (57% chose this)
  • None of the above (14% chose this)
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The efficiency of a grid-bias modulated stage should be:
  • Maximum at complete modulation (0% chose this)
  • Minimum at zero modulation (33% chose this)
  • Either A or B (50% chose this)
  • None of the above (17% chose this)
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To increase the power output of a storage cell:
  • Low internal resistance is desirable (40% chose this)
  • High internal resistance is desirable (20% chose this)
  • Low terminal voltage under load is desirable (40% chose this)
  • None of the above (0% chose this)
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What can be done in a Heising modulation system to obtain 100% modulation?
  • Use a series resistor between the amplifier and modulator in the DC plate supply (0% chose this)
  • Nothing needs to be done (17% chose this)
  • Use a series capacitor between amplifier and modulator in the DC grid supply (17% chose this)
  • Both A and C (67% chose this)
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What is an operating control requirement of a ship station using telegraphy?
  • The ship station must be capable of automatically changing from telegraphy transmission to telegraph reception (20% chose this)
  • A ship station control operator must stand watch on emergency channels at all times (40% chose this)
  • Only a licensed First Class Radiotelegraph Operator may operate a ship station (20% chose this)
  • The ship station must be capable of changing from one radio channel to another within five seconds (20% chose this)
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Keying can be accomplished at various points in a radiotelegraph transmitter. Some are:
  • At the primary of power transformer, at filament centertap, at screen grid circuit (0% chose this)
  • At the control grid circuit, at the DC supply (20% chose this)
  • A or B (80% chose this)
  • None of the above (0% chose this)
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____ are used in a DC motor to reduce brush sparking without moving the brushes:
  • Interpoles (0% chose this)
  • Commutating poles (33% chose this)
  • Either A or B (67% chose this)
  • None of the above (0% chose this)
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What must every examination for the code portion of a radiotelegraph license contain?
  • Applicants for Commercial Radiotelegraph licenses must be examined using a message format that they are likely to receive aboard ship (0% chose this)
  • Both a telegraphy sending and a receiving distress signals (0% chose this)
  • The proper transmission of radiotelegraph distress signals (0% chose this)
  • All alphabet letters, all numerals, period, comma, question mark, slant mark and prosigns AR, BT, and SK (100% chose this)
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Assuming a power source to have a fixed value of internal impedance, maximum power will be transferred to the load when:
  • The load impedance equals the internal impedance of the source (80% chose this)
  • The load impedance is higher than the source impedance (20% chose this)
  • The load impedance is lower than the source impedance (0% chose this)
  • None of the above (0% chose this)
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A shunt-wound DC motor:
  • Has a practically constant speed under widely varying load conditions (25% chose this)
  • Has poor speed regulation under varying load conditions (50% chose this)
  • High starting torque (0% chose this)
  • None of the above (25% chose this)
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Two dissimilar metals joined together and producing a current between them when the junction is heated is:
  • A point contact type transistor (0% chose this)
  • A thermocouple (60% chose this)
  • A junction contact type transistor (20% chose this)
  • A solenoid (20% chose this)
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To adjust a regenerative receiver for maximum sensitivity:
  • The station is tuned in with the receiver in the oscillating condition (0% chose this)
  • Slowly back the regeneration control off until the receiver just breaks out of oscillation and is also below the fringe howl point (40% chose this)
  • First A then B (60% chose this)
  • First B then A (0% chose this)
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The prefix " meg " means:
  • Multiply by 1,000,000 whatever quantity follows (57% chose this)
  • Multiply by 100,000 whatever quantity follows (29% chose this)
  • Multiply by 1,000 whatever quantity follows (14% chose this)
  • Divide by 1,000,000 whatever quantity follows (0% chose this)
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The difference between a Hertz and Marconi antenna is:
  • The physical length (14% chose this)
  • The positioning of the capacitor feed traps (43% chose this)
  • The grounding of RF shielding (14% chose this)
  • None of the above (29% chose this)
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Communication at frequencies in the order of 15 kHz are usually accomplished by ground waves, and require generation of ____ power outputs for reliable and continuous operation:
  • High power (40% chose this)
  • Low power (0% chose this)
  • Extremely high power (60% chose this)
  • Extremely low power (0% chose this)
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Permeability is:
  • The magnetic field created by a conductor wound on a laminated core and carrying any electric current (0% chose this)
  • The ratio of magnetic flux density in a substance to the magnetizing force which produces it (25% chose this)
  • Polarized molecular alignment in a ferromagnetic material while under the influence of a magnetizing force (0% chose this)
  • Both A and C (75% chose this)
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A defective vacuum tube in a transmitter may be indicated by:
  • Gas glow within the tube (0% chose this)
  • No light from the filament (40% chose this)
  • Reduced output (20% chose this)
  • All of the above (40% chose this)
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Waveguides:
  • A type of transmission line (0% chose this)
  • Hollow rectangular or circular pipe (20% chose this)
  • Fine application as transmission lines (0% chose this)
  • All of the above (80% chose this)
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The conductance (G) of a circuit if 6 A flows when 12 VDC is applied is:
  • 0.5 mho (67% chose this)
  • 1.0 mho (33% chose this)
  • 0.25 mho (0% chose this)
  • None of the above (0% chose this)
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After a distress call has been transmitted, every distress-traffic radiotelegram shall contain what symbol in the preamble?
  • SOS followed by the call signal (0% chose this)
  • The distress signal preceding the call and repeated at the beginning of the preamble (0% chose this)
  • All of the above (100% chose this)
  • None of the above (0% chose this)
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The charging rate of a storage cell charged from a fixed voltage source decreases as the charging progresses opposition to the charging voltage?
  • Because as cell voltages increase, offering more opposition to the charging voltage (0% chose this)
  • When the effective charging potential is reduced, the charging current is decreased (0% chose this)
  • Both A & B (100% chose this)
  • None of the above (0% chose this)
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How does an eligible Second Class Radiotelegraph Operator upgrade his license to First Class?
  • By submitting the necessary Proof-of-Passing Certificates (PPC) from a COLEM along with the required fee and Form 756 to the FCC (83% chose this)
  • By fulfilling the Six Months Service Endorsement requirement (17% chose this)
  • By presenting a one year radiotelegraph experience certification to a commercial radio operator examination manager (0% chose this)
  • By complying with the ITU Provision "D" concerning telegraphy operation in the Maritime Service (0% chose this)
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Use of an AC filament supply is desirable:
  • Mostly for practical reasons. It is easily obtainable (20% chose this)
  • Hum may be introduced into the amplifier (0% chose this)
  • A & B (40% chose this)
  • None of the above (40% chose this)
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What is the minimum radio operator license requirement of a chief radio officer on U.S. passenger ships?
  • First or Second Class Radiotelegraph Operator Certificate with six month endorsement (20% chose this)
  • First Class Radiotelegraph Operator Certificate (60% chose this)
  • General Radiotelephone Operator License (20% chose this)
  • Marine Radio Operator Permit (0% chose this)
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An oscillator in a receiver operating on a frequency near the IF of the receiver:
  • Beats with the IF in the second detector to produce an audible note (25% chose this)
  • May cause audio howl in the receiver (0% chose this)
  • Increases sensitivity (50% chose this)
  • May cause noisy operation of the receiver (25% chose this)
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How would you connect a group of similar cells in a storage battery to obtain the maximum no-bond output voltage?
  • In parallel (20% chose this)
  • In series (80% chose this)
  • In series/parallel (0% chose this)
  • None of the above (0% chose this)
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When increased output is desired from a motor-generator, what is the usual procedure?
  • Decrease the resistance after rheostat in series with the generator field (33% chose this)
  • Increase the resistance of the rheostat in series with the generator field (67% chose this)
  • Output cannot be easily increased (0% chose this)
  • Shut down the motor-generator and restart under full load (0% chose this)
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An open filament on an auto-alarm with a linear detector and an electronic selector will:
  • De-energize the restore relay K-105 (0% chose this)
  • K105 applies voltage to K-100, time delay relay (17% chose this)
  • K106 causes the bell to ring after about 2 minutes (17% chose this)
  • All of the above (67% chose this)
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What space of time should elapse between the transmission of the international auto-alarm signal and the distress call?
  • 2 minutes (17% chose this)
  • 4 minutes (33% chose this)
  • 5 minutes (17% chose this)
  • 10 minutes (33% chose this)
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What is the total resistance of a parallel circuit consisting of a 10 ohm branch and a 25 ohm branch?
  • @ ohms (20% chose this)
  • 10.3 ohms (20% chose this)
  • 7.0 ohms (0% chose this)
  • 7.14 ohms (60% chose this)
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The relationship between the antenna current and radiated power of an antenna:
  • P=I2 X R (0% chose this)
  • P=I2 X radiated resistance (60% chose this)
  • No relationship exists (40% chose this)
  • P=E x I (0% chose this)
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Conductors differ from nonconductors, i.e.:
  • There are a large number of free electrons in a good conductor (25% chose this)
  • There is a small number of free electrons in a non-conductor (0% chose this)
  • There is an equal amount of free electrons in a good conductor and in a non-conductor (0% chose this)
  • A & B (75% chose this)
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The DC bias in a Class A amplifier:
  • Usually is negative as measured at the grid with respect to cathode (0% chose this)
  • Usually is positive as measured at the grid with respect to cathode (75% chose this)
  • Cannot be determined (25% chose this)
  • None of the above (0% chose this)
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What microphones have a high impedance output?
  • Crystal (25% chose this)
  • Dynamic (50% chose this)
  • Any (0% chose this)
  • None of the above (25% chose this)
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In the case of an open secondary winding in a coupling transformer causing no signal in the first AF stage, satisfactory repair could be made by:
  • Replacing the transformer (20% chose this)
  • Disconnecting the secondary winding and changing the coupling system to impedance coupling with a grid resistor and coupling capacitor (20% chose this)
  • A & B (60% chose this)
  • None of the above (0% chose this)
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How can the operator of a LORAN receiver on shipboard identify the transmitting stations that are being received?
  • By their pulse recurrence rate (20% chose this)
  • By reference to their frequency of transmission (40% chose this)
  • None of the above (0% chose this)
  • Both A & B (40% chose this)
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When is a transmitter tuned to reduced power?
  • The receiver is initially reduced because the receiver is very sensitive (25% chose this)
  • The receiver is non adjustable in almost all applications (50% chose this)
  • The receiver has a pre-stage amplifier that self-adjusts (0% chose this)
  • In the doubler stages (25% chose this)
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Ohm's law is stated as:
  • E = IR (0% chose this)
  • I = E / R (0% chose this)
  • R = E / I (25% chose this)
  • All of the above (75% chose this)
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What is the total impedance of a parallel capacitor and inductor with equal values of reactance?
  • Infinite total reactance (17% chose this)
  • Zero total reactance (33% chose this)
  • Parallel impedance is resistive and infinite (17% chose this)
  • B & C (33% chose this)
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Approximately at what speed does the antenna of a navigational radar rotate?
  • At speeds ranging from about 6 to 19 RPM (17% chose this)
  • At speeds ranging from about 6 to 15 RPM (17% chose this)
  • At speeds ranging from about 15 to 30 RPM (33% chose this)
  • At speeds ranging from about 20 to 40 RPM (33% chose this)
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Upon hearing an SOS, what should an operator do?
  • Should repeat the SOS to all traffic (0% chose this)
  • Immediately cease all transmissions capable of interfering with the distress traffic (25% chose this)
  • Contact the vessel in distress (63% chose this)
  • None of the above (13% chose this)
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RF interference may be minimized:
  • By the use of brush by-pass capacitors (0% chose this)
  • Low frequency filters (20% chose this)
  • Shielding of long connecting leads (0% chose this)
  • All of the above (80% chose this)
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While the vessel is in the open sea, how frequently must the specific gravity of the emergency battery be taken?
  • Every 12 hours (0% chose this)
  • Once daily (75% chose this)
  • Every 48 hours (25% chose this)
  • Once every week (0% chose this)
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The turns ratio of a transformer varies:
  • As the square root of the impedance ratio (17% chose this)
  • As the square of the impedance ratio (50% chose this)
  • As one-half the impedance ratio (17% chose this)
  • As twice the impedance ratio (17% chose this)
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If a 1500 kHz radio wave is modulated by a 2000 Hz sine wave tone, what frequencies does the modulated wave contain?
  • 1500 kHz , 1502 kHz , 1498 kHz (50% chose this)
  • 1500 MHz , 1502 MHz , 1498 MHz (25% chose this)
  • 1500 Hz , 1502 Hz , 1498 Hz (25% chose this)
  • None of the above (0% chose this)
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Why are copper oxide rectifiers, associated with DC voltmeters to measure AC, unsuitable for the measurement of voltages at radio frequencies?
  • Because of the relatively low shunt capacitance of the copper oxide rectifier (25% chose this)
  • The AC & DC voltages will read low (0% chose this)
  • Because of the relatively large shunt capacitance of the copper oxide rectifier (25% chose this)
  • All of the above (50% chose this)
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Modulation occurring in an RF stage other than the final power amplifier:
  • High level (0% chose this)
  • Low level (40% chose this)
  • Pre-emphasis (60% chose this)
  • Plate (0% chose this)
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What is one of the advantages frequency-shift keying has over "on-off" keying?
  • Increase of transmitter bandwidth (14% chose this)
  • Decrease of signal-to-noise ratio (0% chose this)
  • Increase of signal-to-noise ratio (43% chose this)
  • Both A and C (43% chose this)
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Does grid current flow in a grid-bias modulated stage under modulated conditions?
  • Grid current may exist during the positive porions of the AF cycle (0% chose this)
  • Grid current may cause distortion (0% chose this)
  • A and B (100% chose this)
  • None of the above (0% chose this)
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What is the primary purpose of the screen grid of the tetrode?
  • Reduces the grid to plate capacitance, making it unnecessary to neutralize RF amplifiers except at very high frequencies (0% chose this)
  • Makes the plate current substantially independent of plate voltage, permitting much higher values of amplification (20% chose this)
  • Both A & B (80% chose this)
  • None of the above (0% chose this)
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In a tuned RF receiver the heterodyne method, over the autodyne reception, has:
  • Great sensitivity (0% chose this)
  • More stable operation of the circuit (20% chose this)
  • Wider control of the beat-frequency (0% chose this)
  • All of the above (80% chose this)
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If the coupling capacitor leaked in a resistance-coupled audio frequency amplifier:
  • Excessive plate current would result (0% chose this)
  • A large value of grid current would result (20% chose this)
  • There would be extreme distortion, and very low gain (20% chose this)
  • All of the above (60% chose this)
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The prefix " micro " means:
  • Divide by 1,000,000 whatever quantity follows (100% chose this)
  • Multiply by 1,000,000 whatever quantity follows (0% chose this)
  • Add 1,000,000 to whatever quantity follows (0% chose this)
  • Divide by 1,000 whatever quantity follows (0% chose this)
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What is indicated by the bearing obtained from the use of a unilateral radio direction finder?
  • The direction of another station (20% chose this)
  • The sense of direction of the originating station (20% chose this)
  • All bearings are from (40% chose this)
  • None of the above (20% chose this)
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The formula for finding power in a DC circuit when current and voltage are known:
  • P = EI (50% chose this)
  • P = ( I squared ) R (0% chose this)
  • PF = W/IE (25% chose this)
  • None of the above (25% chose this)
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The screen grid in a vacuum tube:
  • Makes it unnecessary to neutralize RF amplifiers except at very high frequencies, (33% chose this)
  • Makes it possible to obtain much higher values of amplification than with triodes (0% chose this)
  • A & B (33% chose this)
  • None of the above (33% chose this)
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On a United States vessel equipped with an approved auto-alarm, where is the control button which silences the warning bells located?
  • On the navigation bridge (20% chose this)
  • In main engineering control (20% chose this)
  • In the main radiotelegraph operating room (60% chose this)
  • None of the above (0% chose this)
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The unit of AC impedance in a circuit is:
  • Ohm (25% chose this)
  • Mho (75% chose this)
  • Joule (0% chose this)
  • None of the above (0% chose this)
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What is the primary purpose of the suppressor grid of a pentode?
  • Is highly negative with respect to the plate and returns secondary emission to the plate, increasing the permissible gain and the tube efficiency (20% chose this)
  • Reduces interelectrode capacitance between control grid and plate making plate efficiency about 10% greater than a triode (20% chose this)
  • Both A & B (60% chose this)
  • Neither of the above (0% chose this)
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If a receiver storage A battery could not be kept charged, and maintain the required watch period, what should you do?
  • Increase the charging rate (0% chose this)
  • Get a new battery (0% chose this)
  • Discontinue the required watch period (0% chose this)
  • B & C (100% chose this)
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What is the principal function of a vertical sense antenna associated with a unilateral radio direction finder?
  • To determine from which direction the signal is coming (0% chose this)
  • A vertical sense antenna is not associated with a radio direction finder (60% chose this)
  • Unilateral radio direction finders are associated with loop antennas (40% chose this)
  • None of the above (0% chose this)
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The operation of a dynatron oscillator depends on what?
  • The positive emission from the anode (20% chose this)
  • The secondary emission from the anode (0% chose this)
  • Cathode being in saturation (20% chose this)
  • Positive resistance characteristic of the tetrode tube (60% chose this)
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Poor regulation in a power supply may be caused by:
  • No bleeder resistance (0% chose this)
  • High resistance filter chokes (20% chose this)
  • Insufficient filter capacity (0% chose this)
  • All of the above (80% chose this)
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The center-tap connection in a filament supply transformer:
  • Prevents hum voltages from modulating the normal signal (0% chose this)
  • The voltage change on one side of the filament will be effectively cancelled out by an equal and opposite voltage change at the other side of the filament, yielding no hum (0% chose this)
  • A & B (100% chose this)
  • None of the above (0% chose this)
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Generally used to prevent any undesired frequencies from appearing in the output of a receiver:
  • Wave trap (33% chose this)
  • Wave guide (33% chose this)
  • Ripple filter (33% chose this)
  • Tarody screen (0% chose this)
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A resistance across which a constant voltage is applied is doubled. What power dissipation will result?
  • One half (50% chose this)
  • One fourth (25% chose this)
  • Doubled (25% chose this)
  • None of the above (0% chose this)
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Use of a low pass filter network:
  • Ripple filter in power supplies, harmonic suppression filters in antenna systems (33% chose this)
  • Line noise filters, tone control systems (0% chose this)
  • Crossover networks, output filters of detector circuits (17% chose this)
  • All of the above (50% chose this)
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How may the range of a thermocouple ammeter be increased?
  • By using a current transformer (0% chose this)
  • By using a capacitor shunt (33% chose this)
  • Both A & B (33% chose this)
  • By using a resistor shunt (33% chose this)
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What stations shall be in control of distress traffic?
  • Control of the distress traffic shall be with the station first hearing the call (0% chose this)
  • The control of the distress traffic rests with the mobile station in distress (0% chose this)
  • With the mobile station which sends the distress call in the event that the station in distress is not able to transmit it (17% chose this)
  • Both B & C (83% chose this)
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A ____ provides a very high degree of selectivity in a receiver:
  • Crystal filter (40% chose this)
  • Low pass filter (20% chose this)
  • Bleeder resistor (40% chose this)
  • By-pass capacitor (0% chose this)
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Part of the secondary winding of a transmitters power transformer is accidentally shorted. What should be the immediate effect?
  • The current would rise to an excessive value and trip the circuit breaker (0% chose this)
  • The short would burn the transformer (50% chose this)
  • The current in the secondary winding would decrease (50% chose this)
  • None of the above (0% chose this)
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The total impedance of a series AC circuit with an inductive reactance of 24 ohms, a resistance of 16 ohms, and a capacitive reactance of 16 ohms is:
  • 20 ohms (0% chose this)
  • 16 ohms (80% chose this)
  • 10 ohms (20% chose this)
  • None of the above (0% chose this)
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Why is it necessary to use two tubes in a Class B audio amplifier?
  • To prevent the excessive distortion which would result from the use of only one tube in Class B (33% chose this)
  • To eliminate hum (0% chose this)
  • A & B (67% chose this)
  • None of the above (0% chose this)
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Instruments used to indicate various DC currents and voltages in a transmitter may be protected against damage to stray RF by:
  • Insufficient grid blocking bias is applied to the grid when the key is open (0% chose this)
  • Shorted bias resistor (0% chose this)
  • Shorted key-click filter (0% chose this)
  • All of the above (100% chose this)
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The maximum negative anode voltage with respect to the cathode. It equals the DC voltage at the input to the plus the peak AC voltage applied during the nonconducting portion of the cycle of operation of the tube:
  • Maximum inverse plate voltage (17% chose this)
  • Mutual conductance (17% chose this)
  • Both A & B (50% chose this)
  • None of the above (17% chose this)
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What is the meaning of "zero beat" as used in connection with frequency measuring equipment?
  • Zero beat occurs when two frequencies are being mixed together and have no difference frequency between them (60% chose this)
  • To achieve this the frequencies must be suppressed (20% chose this)
  • The transmitter must be nulled (20% chose this)
  • None of the above (0% chose this)
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Decibel is:
  • The unit used to express the ratio between two sound power levels (20% chose this)
  • The unit used to express the ratio between two electrical power levels (20% chose this)
  • Both A & B (60% chose this)
  • None of the above (0% chose this)
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Decrease in capacity of an Edison-type storage cell can be caused by:
  • Frequent overheating, and operating conditions over 115 degrees fahrenheit (0% chose this)
  • Charging at less than the normal rate (17% chose this)
  • Adding impure water to the electrolyte, or a weak or aged electrolyte (0% chose this)
  • All of the above (83% chose this)
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What is the directional reception pattern of a loop antenna?
  • A vertical loop antenna has a bidirectional pattern which is maximum in the directions in the plane of the loop, and minimum in the directions broadside to the loop (33% chose this)
  • A horizontal loop antenna is nondirectional along the plane of the loop. It has minimum radiation or reception vertically (0% chose this)
  • A horizontal loop antenna is directional along the plane of the loop antenna (0% chose this)
  • Both A & B (67% chose this)
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The sensitivity of a 3 circuit receiver is controlled by:
  • The setting of the regeneration control (40% chose this)
  • The setting of the audio frequency control (20% chose this)
  • The setting of the radio frequency control (0% chose this)
  • The setting of the beat frequency oscillator (40% chose this)
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While a vessel is in port, how frequently should the emergency equipment be tested?
  • Once a day (25% chose this)
  • Once a week (25% chose this)
  • Once a month (13% chose this)
  • Only when the vessel is ready to leave port (38% chose this)
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If a field strength is 100 microvolts per meter at 100 miles, what is the field strength at 200 miles?
  • 50 microvolts (33% chose this)
  • 10 microvolts (33% chose this)
  • 200 microvolts (33% chose this)
  • 150 microvolts (0% chose this)
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Which antenna system has the ability to discriminate between various directions of receiving or transmitting?
  • 1/4 stub bi-directional (0% chose this)
  • Multi-band Marconi 1/2 wave (0% chose this)
  • 1/2 wavelength Yagi perpendicular polarized antenna (25% chose this)
  • Single element vertical antenna (75% chose this)
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If the auto-alarm bell rings and the release button doesn't stop it:
  • Bell relay K-107 could be stuck, or there could be an open filament (25% chose this)
  • The alarm bell relay circuit ground could be bad (0% chose this)
  • There could be failure or low line voltage (25% chose this)
  • All of the above (50% chose this)
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What time system shell be used in making log entries with respect to the observance of the international silent period?
  • Zulu time according to the twelve hour system (25% chose this)
  • Greenwich Mean Time according to the 24 hour system (75% chose this)
  • Zulu time according to the 12 hour time (0% chose this)
  • None of the above (0% chose this)
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What point on a shipboard antenna system displays the maximum potential?
  • The end of the antenna furthest from the transmission line connections (40% chose this)
  • The end of the antenna closest to the transmission line connections (0% chose this)
  • Near the center of the antenna (20% chose this)
  • None of the above (40% chose this)
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Transistors may be compared to a conventional triode vacuum tube functionally:
  • Emitter corresponds to the cathode (0% chose this)
  • Collector corresponds to the plate (20% chose this)
  • Base corresponds to the grid (0% chose this)
  • All of the above (80% chose this)
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What type of radio receiver do not respond to static interference?
  • AM receivers are less responsive (0% chose this)
  • FM receivers have better sensitivity to such interference (40% chose this)
  • Both AM & FM (40% chose this)
  • B & C (20% chose this)
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The average fully charged voltage of a lead-acid cell is:
  • 1.0 V (25% chose this)
  • 1.56 V (25% chose this)
  • 2.06 V (25% chose this)
  • 2.5 V (25% chose this)
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Halving the cross-sectional area of a conductor will:
  • Double the resistance (60% chose this)
  • Half the resistance (20% chose this)
  • Not affect the resistance (20% chose this)
  • None of the above (0% chose this)
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Characteristics of a vacuum tube operating as a class B amplifier:
  • Low plate circuit efficiency, about 25%; practically no grid driving power; plate current flowing for 360 degrees of each cycle; practically no distortion of the output waveshape (0% chose this)
  • Plate circuit efficiency, about 50-60%; plate current flows slightly more than 180 degrees of each cycle, medium power output (100% chose this)
  • High efficiency, up to 80%; plate current drawn in bursts; great distortion of output waveshape (0% chose this)
  • None of the above (0% chose this)
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When passing through areas of static charge, high voltages can accumulate on antennas which are insulated from ground. What protects a connected receiver from damage?
  • Lightning arresters and suppressors (33% chose this)
  • Protection diodes on receiver input (0% chose this)
  • Capacitive coupling and static dissipative circuits (17% chose this)
  • Any combination of the above (50% chose this)
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Edison type batteries:
  • Have plates up nickel (0% chose this)
  • Have plates of iron (0% chose this)
  • Have plates of compounds of nickel and iron (40% chose this)
  • All of the above (60% chose this)
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The voltage of an alternator will:
  • Decrease under load (100% chose this)
  • Increase under load (0% chose this)
  • Load has no effect on voltage (0% chose this)
  • None of the above (0% chose this)
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What is the effect of incorrect grid bias in a Class A amplifier?
  • Distortion of the output waveshape (0% chose this)
  • Possible excessive plate dissipation if the bias is too low (20% chose this)
  • Both A & B (80% chose this)
  • None of the above (0% chose this)
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What answer format is accepted on commercial radiotelegraph license contain?
  • The examiner may use any answer format which ascertains that the examinee can comprehend the message transmitted (0% chose this)
  • Any of the following: one minute solid copy, answering seven out of ten question, fill-in-the-blank, or multiple choice questions (20% chose this)
  • Examinees are required to receive international Morse code messages by ear for a period of one minute without error (80% chose this)
  • Examinees must obtain a passing mark of 75% or higher on questions concerning the transmitted telegraphy message (0% chose this)
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What examination requirements are necessary to obtain a Second Class Radiotelegraph Operator's Certificate?
  • Written Element 1 (radio law), Element 3 (electronic fundamentals), Element 5 (radiotelegraph operations) and sending/receiving 16/20 words per minute (40% chose this)
  • Telegraphy Element 1 (sending/receiving 16 code groups per minute) and Telegraphy Element 2 (16 code groups and 20 words per minute text.) (0% chose this)
  • Successful completion of written test Elements 1, 5 and 6 on basic radio law and operating practices plus telegraphy Elements 1 and 2 (40% chose this)
  • Successful completion of written test Elements 1, 3, 5 and 6 on basic radio law and operating practices plus telegraphy Elements 1 and B (20% chose this)
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The chief advantage of Class A audio operation is compared to the other classes of audio-frequency amplifiers:
  • Hum currents are in phase (0% chose this)
  • Low distortion of the output signal (100% chose this)
  • Tendency for regeneration is increased (0% chose this)
  • Elimination of cathode bypass capacitors (0% chose this)
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A vertical loop antenna has a:
  • Omni-directional pattern which is maximum in the directions of the plane of the loop, and minimum in the directions broadside to the loop (17% chose this)
  • Non-directional with regard to compass points (17% chose this)
  • Has minimum radiation or reception in the direction of the ends of the antenna (0% chose this)
  • Has a bi-directional pattern which is maximum in the direction of the plane of the loop, and minimum in the directions broadside to the loop (67% chose this)
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Excessive plate current of an RF amplifier may be caused by:
  • Plate-tank circuit off resonance, defective tube (0% chose this)
  • Excessive loading of plate tank, insufficient bias, parasitic oscillations (20% chose this)
  • Excessive plate and screen voltage, excessive excitation voltage, improper neutralization (0% chose this)
  • All of the above (80% chose this)
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In all cases other than those in which the transmitter output must be maintained at a fixed value, what amount of power should be employed for routine communications?
  • The maximum amount of power to maintain communications (0% chose this)
  • The transmitter must be maintained at a fixed value (0% chose this)
  • The minimum amount of power necessary to ensure reliable communications (100% chose this)
  • None of the above (0% chose this)
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Feeding back into the control grids of the IF and RF amplifiers a negative DC bias which is proportioned to the average magnitude of the received carrier wave accomplished:
  • Rhymed effect (0% chose this)
  • Automatic volume control (0% chose this)
  • Neutralization (100% chose this)
  • Refraction (0% chose this)
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What is the primary purpose of the control grid of the triode?
  • To provide a means of obtaining amplification (43% chose this)
  • To neutralize RF amplifiers (14% chose this)
  • Blocks passage of electrons (43% chose this)
  • None of the above (0% chose this)
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By what factor must the voltage of an ac circuit, as indicated on the scale of an AC voltmeter, be multiplied to obtain the average voltage value?
  • By the factor of 0.9 (50% chose this)
  • By the factor of 9.0 (25% chose this)
  • By the factor of A.0 (25% chose this)
  • By the factor of B.0 (0% chose this)
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Important factors in the operation of the vacuum tube as a frequency doubler are:
  • Plate tank should be tuned to twice the grid circuit frequency (0% chose this)
  • The grid bias should be very large, the grid driving voltage must be very large, the plate voltage should be comparatively high (0% chose this)
  • The plate tank circuit should have a low C to L ratio (25% chose this)
  • All of the above (75% chose this)
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The functioning of a grid-leak detector:
  • Depends on the ability of the grid leak and capacitor to follow the average grid current variations which are directly proportioned to the modulation envelope (0% chose this)
  • Depends on second harmonic distortion (0% chose this)
  • Very sensitive to weak signals (29% chose this)
  • A & C (71% chose this)
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A vacuum tube operated Class C audio amplifier is not feasible, either in single or push-pull:
  • Since the plate current only flows 120 degrees, even in push-pull, only 2/3 of the cycle is reproduced and the resultant distortion would be unacceptable for audio (0% chose this)
  • Tank circuits, which replace the missing portions of the cycle, can't be used in an audio amplifier because they only operate on one frequency (25% chose this)
  • A & B (75% chose this)
  • None of the above (0% chose this)
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What may cause the plates of a lead-acid call to buckle?
  • Excessive sulfation (0% chose this)
  • Overheating (17% chose this)
  • Overdischarging of the battery (17% chose this)
  • All of the above (67% chose this)
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"Load" on a vacuum tube commonly refers to:
  • The impedance through which plate current flows to produce a useful output (20% chose this)
  • Increases as the load impedance approaches the internal plate impedance in value (20% chose this)
  • A & B (40% chose this)
  • None of the above (20% chose this)
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Adding an iron core to an air-core inductance:
  • Increases the inductance (40% chose this)
  • Decreases the inductance (40% chose this)
  • Does not affect the inductance (20% chose this)
  • Causes parasitic oscillations in the inductor (0% chose this)
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If you apply DC voltage to the opposite plane surfaces of a quartz crystal:
  • The crystal plate will always undergo a physical distortion (0% chose this)
  • The crystal might crack under the strain of displacement caused by too much voltage (33% chose this)
  • A & B (50% chose this)
  • None of the above (17% chose this)
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Harmonic radiation is:
  • Radiation occurring on frequencies that are whole multiples of the original frequency (17% chose this)
  • Is always higher than the fundamental frequency (17% chose this)
  • Reduced by proper tuning of the transmitter (0% chose this)
  • All of the above (67% chose this)
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The auto-alarm bell rings and the release button stops it:
  • There could be reception of a true alarm signal (20% chose this)
  • There could be reception of a false alarm signal (20% chose this)
  • A or B (60% chose this)
  • Neither A or B (0% chose this)
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Intermittent ringing of the bells of an auto alarm with a linear detector and an electronic selector could be caused by:
  • An intermittent vacuum tube filament (0% chose this)
  • Fluctuating line voltage (0% chose this)
  • Faulty contacts or relay adjustment of warning relay receiver (50% chose this)
  • All of the above (50% chose this)
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For 100% modulation, DC power input to the modulated RF amplifier should:
  • Be the same as the AC power from the modulation (80% chose this)
  • Be 1/2 the AC power from the modulation (20% chose this)
  • Be 1/4 the AC power from the modulation (0% chose this)
  • None of the above (0% chose this)
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Characteristics of a vacuum tube operating as a Class C amplifier:
  • Low plate circuit efficiency, about 25%; practically no grid driving power; plate current flowing for 360 degrees of each cycle; practically no distortion of the output waveshape (0% chose this)
  • Plate circuit efficiency, about 50-60%; plate current flows slightly more than 180 degrees of each cycle; medium power output (50% chose this)
  • High plate circuit efficiency, up to 80%; plate current drawn in bursts; great distortion of output waveshape (0% chose this)
  • None of the above (50% chose this)
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A power detector may be operated:
  • As a square law detector (0% chose this)
  • As a linear detector (50% chose this)
  • As either a square law detector or a linear detector (50% chose this)
  • None of the above (0% chose this)
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With what type(s) of emission and upon what frequency should a transmitter be adjusted to transmit a distress call?
  • The distress wave of 600 kHz and type C emission (0% chose this)
  • The distress wave of 400 kHz and type C emission (17% chose this)
  • The international distress wave of 500 kHz / type A-2 OR B emission (67% chose this)
  • None of the above (17% chose this)
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What is the principal port of the United States, on the Pacific coast, at which navigation lines terminate?
  • Los Angeles (0% chose this)
  • San Francisco (67% chose this)
  • San Diego (33% chose this)
  • None of the above (0% chose this)
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To avoid damage to components what precautions should be observed in tuning a transmitter?
  • It should be adjusted at reduced power (40% chose this)
  • It should be adjusted under normal power (40% chose this)
  • Plate tank circuits are tuned for maximum DC current (20% chose this)
  • None of the above (0% chose this)
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You intercept "CQ CQ WSV TFC"; what does this mean?
  • General call to all stations (0% chose this)
  • Call letter of a coastal station (0% chose this)
  • Traffic (0% chose this)
  • All of the above (100% chose this)
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The main advantage of a tuned audio frequency amplifier in a receiver used for the reception of CW:
  • A reduction in interference from unwanted signals (20% chose this)
  • The desired audio beat frequency is attenuates (20% chose this)
  • A & B (40% chose this)
  • None of the above (20% chose this)
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During daytime hours, approximately what is the maximum distance in nautical miles from LORAN transmitting stations from which LORAN lines of position can be determined?
  • About 700 miles (0% chose this)
  • During nighttime hours, the maximum distance is increased to about 1800 miles by the use of sky waves (17% chose this)
  • About 1000 miles (50% chose this)
  • About 1500 miles (33% chose this)
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A means of comparing the weight of a volume of liquid with the same volume of distilled water:
  • Specific gravity (60% chose this)
  • Specific mass (0% chose this)
  • Specific volume (40% chose this)
  • None of the above (0% chose this)
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The voltage drop across an individual capacitor of a group of capacitors connected in series across an AC source is:
  • Inversely proportional to the ratio of the capacitance of the capacitor being considered (0% chose this)
  • Inversely proportional to the total capacitance of the combination (40% chose this)
  • Directly proportional to the applied voltage across the series combination (40% chose this)
  • All of the above (20% chose this)
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The auto alarm receiver is tuned to ____ but is able to respond to signals from ____ to ____ (+/- 12.5 kHz)
  • 500 kHz, 487.5 kHz, 512.5 kHz (20% chose this)
  • 500 kHz, 485.0 kHz, 515 kHz (20% chose this)
  • 500 kHz, 490.00 kHz, 510 kHz (40% chose this)
  • 500 kHz, 470.00 kHz, 530 kHz (20% chose this)
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What is the ratio of peak to average value of a sine wave?
  • 1.57 to 1 (20% chose this)
  • 1 to 0.636 (40% chose this)
  • 1 to 1 (0% chose this)
  • A & B (40% chose this)
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Basically, am FM receiver is a conventional superheterodyne but differs in:
  • The method of detection (0% chose this)
  • The reduction of sensitivity to amplitude modulation (0% chose this)
  • De-emphasis (0% chose this)
  • All of the above (100% chose this)
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Why is a center top usually provided for vacuum tube plate and grid return circuits when and AC filament supply is used?
  • To prevent hum voltage from modulating the normal signals (0% chose this)
  • To allow more filament current (20% chose this)
  • A & B (80% chose this)
  • None of the above (0% chose this)
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In determining a "fix" position by a marine LORAN system, what is the minimum number of land transmitters involved?
  • A master & a slave station (40% chose this)
  • 1 slave station (40% chose this)
  • 2 slave stations & 1 master station (20% chose this)
  • Four, or two pairs of "master and "slave" stations (0% chose this)
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What is the reception pattern of a vertical antenna?
  • It has minimum radiation or reception vertically (0% chose this)
  • A vertical Jackson antenna has a pattern which is nondirectional with regard to all compass points (60% chose this)
  • It has maximum radiation or reception vertically (20% chose this)
  • None of the above (20% chose this)
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Laminated iron is used in armature and field construction to:
  • Reduce eddy current losses (20% chose this)
  • Offer a number of high-resistance paths to Eddy currents (0% chose this)
  • A or B (60% chose this)
  • None of the above (20% chose this)
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If L and C in a parallel resonant circuit resonants at 1000 kHz are so varied that their product remains constant, what will be the resulting resonant frequency?
  • 10,000 kHz (14% chose this)
  • 100 kHz (29% chose this)
  • 1 MHz (29% chose this)
  • None of the above (29% chose this)
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What figure represents the reception pattern of a properly adjusted unilateral radio direction finder?
  • A cardioid (0% chose this)
  • A figure eight (25% chose this)
  • A heart shaped figure (0% chose this)
  • Both A & C (75% chose this)
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A shorted grid capacitor in a three-circuit regenerative receiver would:
  • Render the receiver mostly or completely inoperative (0% chose this)
  • Have no noticeable effect (0% chose this)
  • Some forms of plate detection might occur but with considerably reduced sensitivity and volume (40% chose this)
  • A & C (60% chose this)
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A battery with a terminal voltage of 12.5 V is to be trickle-charged at a 0.5 A rate. What resistance should be connected in series with the battery to charge from a 110 V line?
  • 195 ohms (40% chose this)
  • 300 ohms (20% chose this)
  • 95 ohms (20% chose this)
  • None of the above (20% chose this)
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Name four conducting materials in order of their conductivity.
  • Gold, silver, copper, platinum (50% chose this)
  • Silver, gold, zinc, platinum (25% chose this)
  • Silver, copper, zinc, aluminum (25% chose this)
  • Aluminum, zinc, copper, platinum (0% chose this)
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The plate current of the final RF amplifier in a transmitter increases and radiation decreases, if the antenna circuit is in good order, what could be the cause?
  • Neutralization may have been upset (0% chose this)
  • The plate circuit may have been detuned, bias may have been lost (50% chose this)
  • Grid excitation may have decreased, there may be a faulty tube, or there may be parasitic oscillations (17% chose this)
  • All of the above (33% chose this)
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When two sine waves of the same frequency do not reach their maximum or minimum values simultaneously:
  • A phase difference exists (17% chose this)
  • A phase difference does not exist (17% chose this)
  • The sign waves are out of phase (0% chose this)
  • A & C (67% chose this)
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What is the antenna requirement aboard a survival craft equipped with a non-portable radiotelegraph installation?
  • The minimum lifeboat antenna requirement is an HF half-wave dipole capable of efficiently tuning distress frequencies (25% chose this)
  • The antenna must be single wire inverted L type of maximum practicable length and height above the waterline (0% chose this)
  • The antenna must be tested at least once during each voyage and a minimum of once a week on longer voyages (25% chose this)
  • The antenna must be located a minimum of 8 meters above the waterline to insure the safety of passengers (50% chose this)
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A "choke" coil:
  • Offers a relatively high impedance to AC currents (0% chose this)
  • Has a high "Q" (low RF losses) (0% chose this)
  • Offers a low resistance to DC currents (33% chose this)
  • All of the above (67% chose this)
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What are effects of parasitic oscillations?
  • Change of bias (0% chose this)
  • Reduced efficiency of the amplifier tube (20% chose this)
  • Distortion of the modulated wave (0% chose this)
  • All of the above (80% chose this)
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A case in which the grid is held at an excessively negative value for a period of time thereby cutting off plate current:
  • Blocked grid (40% chose this)
  • Blocked plate (20% chose this)
  • Motorboating (40% chose this)
  • Tuned grid (0% chose this)
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High or low frequency oscillations occurring in circuits other than the original tank desired output frequencies are:
  • Harmonics (17% chose this)
  • Parasitic oscillations (50% chose this)
  • Hysteresis (33% chose this)
  • Eddy currents (0% chose this)
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A regenerative, oscillating-detector receives directly coupled to an antenna:
  • May radiate energy that can beat with other carrier frequencies and cause heterodyning interference in a number of receivers (60% chose this)
  • Cannot radiate energy (20% chose this)
  • Radiates extremely high energy (20% chose this)
  • None of the above (0% chose this)
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What is the maximum current carrying capacity of a resistor of 5000 ohms, 200 watts?
  • 0.2 A (0% chose this)
  • 1 A (25% chose this)
  • 1.2 A (50% chose this)
  • None of the above (25% chose this)
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An artificial antenna sometimes used in testing a transmitter:
  • Dummy antenna (0% chose this)
  • Dummy load (25% chose this)
  • Prevents undesired radiation (50% chose this)
  • All of the above (25% chose this)
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The formula for determining the power in a DC circuit when the voltage and resistance are known is:
  • P = ( E squared) R (0% chose this)
  • P = EI (50% chose this)
  • P = ( I squared) R (50% chose this)
  • PF = W/IE (0% chose this)
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How many capacitors of 400 volts and 2 microfarad each would be necessary to obtain a combination rated at 1600 volts and 1.5 microfarad?
  • 10 (0% chose this)
  • 12 (0% chose this)
  • 14 (67% chose this)
  • 16 (33% chose this)
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What is a requirement of all transmitting apparatus used aboard United States vessels?
  • Equipment must be approved by the U.S. Coast Guard for maritime mobile use (0% chose this)
  • Certification is required by the International Maritime Organization (IMO) (0% chose this)
  • Only equipment that has been type accepted by the FCC for Part 80 operations is authorized (75% chose this)
  • Programming of all maritime channels must be performed by a licensed Marine Radio Operator (25% chose this)
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Output voltage of a dynamotor may be regulated:
  • Only by changing the speed of the motor (0% chose this)
  • A series resistance in the output line could be used to reduce the available output voltage (0% chose this)
  • Either A or B (100% chose this)
  • None of the above (0% chose this)
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Essentials for making a good solder connection are:
  • Bright, clean parts (25% chose this)
  • Plenty of heat with the minimum amount of solder used (25% chose this)
  • Discontinue operating on high power (25% chose this)
  • None of the above (25% chose this)
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If the voltage to a circuit is doubled and the resistance is increased to three times the original value, what will be the final current?
  • 1/3 the original current (25% chose this)
  • 2/3 the original current (50% chose this)
  • 3 times the original current (25% chose this)
  • None of the above (0% chose this)
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The speed of a series DC motor may increase and destroy the motor by centrifugal action:
  • When operated without a load (25% chose this)
  • When operated on AC (0% chose this)
  • When operated under varying load (75% chose this)
  • None of the above (0% chose this)
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What is indicated by the bearing obtained from the use of a bilateral radio direction finder?
  • A line of direction which passes through two stations (25% chose this)
  • A line of direction which passes through the originating station (25% chose this)
  • A line of direction can read in either direction (50% chose this)
  • None of the above (0% chose this)
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The radiated wavelength of a Hertzian antenna is:
  • 1/2 the physical length of the modulated coaxial (0% chose this)
  • 1/4 the physical length of the modulated RF line (0% chose this)
  • 1/2 the physical length of the antenna (75% chose this)
  • Approximately twice the physical length of the antenna (25% chose this)
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What is the maximum authorized bandwidth of a high frequency radiotelegraphy signal, emission A1A, in the maritime service?
  • 0.4 kHz (0% chose this)
  • 0.2 kHz (25% chose this)
  • Minimum necessary to complete necessary communications (25% chose this)
  • 1 kHz (50% chose this)
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Power factor is defined as:
  • The ratio between the resistance and the impedance in a circuit (0% chose this)
  • The ratio between the true power and the apparent power of a circuit (40% chose this)
  • Both A&B (60% chose this)
  • None of the above (0% chose this)
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Harmonic radiation by a transmitter may be prevented:
  • By using a suitable crystal filter (0% chose this)
  • By using a Faraday shield between the final amplifier and antenna circuit (25% chose this)
  • By using suitable tuned filters in the transmission line system (0% chose this)
  • B & C (75% chose this)
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In the transmission of the international Morse code, what are the relative time lengths of dashes, dots?
  • Dashes are about four times as long as dots (0% chose this)
  • Dots are about half the length of dashes (75% chose this)
  • Dashes are about three times as long as dots (0% chose this)
  • None of the above (25% chose this)
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A compound-wound DC motor:
  • Has constant speed under changing load conditions (0% chose this)
  • Low starting torque (25% chose this)
  • High starting torque (25% chose this)
  • A & B (50% chose this)
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Plate current flows for less than 180 degrees (about 120 degrees when the grid bias is about twice cutoff value) in what class amplifier?
  • A (0% chose this)
  • B (25% chose this)
  • C (25% chose this)
  • AB (50% chose this)
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What precautions should an operator or serviceman observe when working with cathode-ray tubes?
  • The tube must not strike against any hard surface (0% chose this)
  • The tube might implode (33% chose this)
  • Safety goggles and gloves should be worn when handling cathode-ray tubes (0% chose this)
  • All of the above (67% chose this)
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What is the "mixer" tube in the superheterodyne receiver?
  • The first detector (50% chose this)
  • The second detector (25% chose this)
  • The beat frequency oscillator (25% chose this)
  • None of the above (0% chose this)
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The correct formula for determining the surge impedance of a quarter wavelength matching line is:
  • Impedance total equal 0.25 over 1 squared (75% chose this)
  • Impedance total equal impedance of the antenna times impedance of the line squared over 1 times C.14 (25% chose this)
  • Impedance zero equal impedance of antenna times impedance of the line squared (0% chose this)
  • None of the above (0% chose this)
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What is the purpose of multiplier resistance used with a voltmeter?
  • Multiplier resistance is not used with a voltmeter (0% chose this)
  • To increase the voltage indicating range of the voltmeter (100% chose this)
  • To decrease the voltage indicating range of the voltmeter (0% chose this)
  • None of the above (0% chose this)
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The negative plate of a lead-acid storage cell:
  • Is composed of pure spongy lead (0% chose this)
  • Is composed of lead peroxide (40% chose this)
  • Is composed of a compound of pure spongy lead and lead peroxide (60% chose this)
  • None of the above (0% chose this)
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What value of sinusoidal audio power is required to insure 100% modulation when the DC plate input to a modulated Class C amplifier has an efficiency of 60 % , and is 200 W?
  • 100 W (20% chose this)
  • 50 W (40% chose this)
  • 25 W (20% chose this)
  • 12 W (20% chose this)
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A tuned RF amplifier stage ahead of the mixer stage in a superheterodyne receiver:
  • Improves receiver sensitivity, improves image rejection (20% chose this)
  • Improves selectivity, improves stability (40% chose this)
  • Improves signal-to-noise ratio, reduced interference (0% chose this)
  • All of the above (40% chose this)
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Vertical shipboard antennas for use in the MF band (410-525 kHz) are often fitted with top-hat loading sections. What is the purpose of these structures?
  • Provides aerodynamic compensation for stress during high winds (0% chose this)
  • Permits a physically short antenna to appear electrically longer (50% chose this)
  • Improves the near-field radiated pattern at the expense of the far-field pattern (50% chose this)
  • Prevents salt build-up on antennas from shunting RF energy to ground (0% chose this)
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If a 60 Hz transformer is connected to a 120 Hz source of the same voltage:
  • The impedance of the transformers would be greater (0% chose this)
  • The current would be reduced (17% chose this)
  • There would be a decrease in power delivered to the load (33% chose this)
  • All the above (50% chose this)
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A high-resistance fixed resistor is shunted across each unit of a high voltage series capacitor bank in the power-supply filter circuit to:
  • Insure that the correct voltage appears across each unit (17% chose this)
  • Discharge the capacitors (83% chose this)
  • Does not insure the correct voltage across each unit (0% chose this)
  • None of the above (0% chose this)
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A special type of power supply filter choke whose inductance is inversely proportioned to values of DC within specified limits is:
  • Smoothing choke (0% chose this)
  • Swinging choke (0% chose this)
  • Radio frequency choke (100% chose this)
  • Audio frequency choke (0% chose this)
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What is a requirement of every commercial operator on duty and in charge of a transmitting system?
  • A copy of the Proof-of-Passing Certificate (PPC) must be on display at the transmitter location (0% chose this)
  • The original license or a photocopy must be posted or in the operator's personal possession and available for inspection (60% chose this)
  • The FCC Form 756 certifying the operator's qualifications must be readily available at the transmitting system site (40% chose this)
  • A copy of the operator's license must be supplied to the radio station's supervisor as evidence of technical qualification (0% chose this)
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If a class B linear final R-F amplifier were in saturation and no modulation what would happen when modulated?
  • The carrier frequency would override the grid-plate current and the result would be positive shift resulting in amplification (0% chose this)
  • The Class B linear amplifier only modulates below cut-off (25% chose this)
  • A condition of negative carrier shift would be the result (25% chose this)
  • Both A and B (50% chose this)
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How is the unilateral effect obtained in a direction finder?
  • With a balancing capacitor (25% chose this)
  • With a compensator (25% chose this)
  • With insulating material (50% chose this)
  • None of the above (0% chose this)
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What effect does excessive coupling between the output circuit of an oscillator and an antenna have?
  • The effect of cross-modulation of nearby frequencies (25% chose this)
  • Instability of the oscillator and feedback op-amp (25% chose this)
  • The oscillator will be very unstable (0% chose this)
  • Frequency discrimination will be unstable (50% chose this)
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If a transmitter is adjusted for maximum power for telegraph, what must be done to be amplitude modulated?
  • The plate voltage must be reduced (0% chose this)
  • The plate voltage must be increased (40% chose this)
  • Tubes would have to dissipate 1.5 times as much power if the plate voltage were not reduced (0% chose this)
  • Both A and C (60% chose this)
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A wavetrap in a receiver:
  • Prevents the effects of any undesired output of the receiver (0% chose this)
  • Generates desired frequencies in the output of the receiver (33% chose this)
  • A & B (67% chose this)
  • None of the above (0% chose this)
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Spare "B" batteries should be stored:
  • In a dry place (25% chose this)
  • In a hot place (25% chose this)
  • Anywhere (25% chose this)
  • A & C (25% chose this)
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How can an R-F amplifier stage be neutralized?
  • Vary the tuning of the plate tank circuit while observing the amp. meter (0% chose this)
  • Vary the tuning of the plate tank circuit while observing the SWR meter (25% chose this)
  • Neutralization is done by circuit design either by increasing the input impedance or lowering the inductance value (0% chose this)
  • Both A and C are correct (75% chose this)
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The first detector in a superheterodyne receiver:
  • Acts as a mixer, providing the action which produces the desired intermediate frequency (0% chose this)
  • The first detector must be operated on the non linear portion of its characteristic to provide the proper action (25% chose this)
  • A & B (75% chose this)
  • None of the above (0% chose this)
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If the voltage of some cells in a battery are found to be reversed, what is indicated?
  • Polarity was reversed while charging (80% chose this)
  • Polarity was doubled while charging (20% chose this)
  • Polarity has no influence of charging (0% chose this)
  • Polarity was correct while charging (0% chose this)
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The keying circuit of the ships transmitter is disconnected:
  • When the auto-alarm antenna switch is placed in the auto-alarm operating position (25% chose this)
  • When the auto-alarm antenna switch is placed in the auto-alarm off position (25% chose this)
  • Manually as desired (50% chose this)
  • None of the above (0% chose this)
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What is the maximum transmitter power that a ship station may radiate using radiotelegraphy emissions on frequencies below 27500 kHz?
  • 400 W (20% chose this)
  • 2 kW, unless a passenger ship 5000 gross tons and over (60% chose this)
  • 3 kW (20% chose this)
  • 1 kW (0% chose this)
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When a radiotelephone transmitter is 100% modulated by sinusoidal waveform , how much antenna current will be observed?
  • 22.5 % increase (67% chose this)
  • 22.5 % decrease (33% chose this)
  • 12.25% increase (0% chose this)
  • No change in antenna current (0% chose this)
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When the first speech-amplifier of a transmitter were overexcited, but the modulation capabilities were not exceeded what would be the effect on the output?
  • The waveform would be sawtooth causing undermodulation (0% chose this)
  • The waveform would be square wave creating cross-modulation (17% chose this)
  • The output would be distorted (33% chose this)
  • Both A and C (50% chose this)
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Three main factors to consider about grid-leak in a vacuum tube transmitter:
  • The value of grid leak current and grid leak anode to grid (0% chose this)
  • The value of grid leak resistance and duration of time the grid current is flowing (50% chose this)
  • Internal resistance of the tube between the grid and cathode (0% chose this)
  • Both B and C (50% chose this)
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Alternators are usually rated in:
  • Volt-amperes output (0% chose this)
  • Watts (50% chose this)
  • Amperes (50% chose this)
  • ***<This answer left blank by the FCC> (0% chose this)
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A carbon microphone should not be:
  • Jarred while in operation (0% chose this)
  • Tapped while in operation (0% chose this)
  • Subjected to violent sound intensities (40% chose this)
  • All of the above (60% chose this)
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Thoriated tungsten is usually used to make:
  • Filaments (67% chose this)
  • Heaters (0% chose this)
  • Cathodes (33% chose this)
  • None of the above (0% chose this)
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The power transformer and rectifier of a radio receiver are designed to supply a plate voltage of 250 V when operating from a 110 V 60 Hz supply, if the transformer is connected to 110 VDC what will happen?
  • The secondary would burn out (33% chose this)
  • The primary would overheat and burn out (0% chose this)
  • The circuit breaker would open to protect the circuit (0% chose this)
  • Either A or B (67% chose this)
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A shunt-fed plate circuit of a vacuum tube amplifier has a short circuit of the plate RF choke. What happens?
  • The plate tank circuit would be effectively shorted (0% chose this)
  • The DC plate current would increase, possibly to excess (60% chose this)
  • No RF output could be expected (0% chose this)
  • All of the above (40% chose this)
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If capacitors of 3, 5, and 7 microfarad are connected in parallel, what is the total capacitance?
  • 9 microfarad (25% chose this)
  • 15 microfarad (0% chose this)
  • 10 microfarad (50% chose this)
  • 3 microfarad (25% chose this)
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The approximate efficiency of a Class A vacuum tube amplifier:
  • 20%-30% (0% chose this)
  • 60% (25% chose this)
  • 85% (50% chose this)
  • 100% (25% chose this)
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A charge due to the accumulation of negative electrons because the plate potential cannot attract all of the electrons leaving the emitter:
  • Getter (0% chose this)
  • Space charge (25% chose this)
  • Plate saturation (75% chose this)
  • None of the above (0% chose this)
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The bias of a grid-modulated R-F stage is adjusted:
  • Below cut-off frequency (0% chose this)
  • At grid saturation (50% chose this)
  • At bias (0% chose this)
  • 1 and half to 3 times plate current cutoff value (50% chose this)
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How would you connect a group of similar cells in a storage battery to obtain the maximum zero resistance current?
  • In parallel (40% chose this)
  • In series (60% chose this)
  • In series/parallel (0% chose this)
  • None of the above (0% chose this)
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If an electrolyte in a lead-acid storage cell becomes low due to evaporation:
  • The level should be brought to about 1/4 inch above the tops of the plates with pure water (50% chose this)
  • The level should be brought to about 1/4 inch above the tops of the plates with tap water (50% chose this)
  • The level should be brought to about 1/4 inch above the tops of the plates with salt water (0% chose this)
  • None of the above (0% chose this)
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Voltage may be expressed by what other expression?
  • Difference of potential (14% chose this)
  • IF drop (14% chose this)
  • Electromotive force (14% chose this)
  • All of the above (57% chose this)
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What types of vacuum tube filaments are reactivated:
  • Barium berylliate (0% chose this)
  • Thoriated tungsten (80% chose this)
  • Nickel (0% chose this)
  • Thorium oxide (20% chose this)
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Two 10 W, 500 ohm resistors in parallel will dissipate how many watts?
  • 20 watts (60% chose this)
  • 10 watts (40% chose this)
  • 30 watts (0% chose this)
  • 40 watts (0% chose this)
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Direction of flow of DC electricity in a conductor can be determined by:
  • A magnetic compass and the left hand rule (0% chose this)
  • A magnetic compass and the right hand rule (40% chose this)
  • Connecting an ammeter with marked polarities in series with the circuit (0% chose this)
  • A & C (60% chose this)
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The system producing A-2 emission by a "chopper" may be thought of:
  • As a double-keying system (0% chose this)
  • The automatic "chopper" turns the transmitter on and off at a rapid rate (50% chose this)
  • The other key is a normal hand operated key (25% chose this)
  • All of the above (25% chose this)
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The effective value of an RF current and the heating value of the current are:
  • The same (25% chose this)
  • Effective value divided by two equals the heating value (25% chose this)
  • Effective value multiplied by two equals the heating value (25% chose this)
  • None of the above (25% chose this)
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What happens to a lower grade of Commercial Radiotelegraph License when a licensee qualifies for a higher grade?
  • The lower grade is allowed to expire and may not be renewed (0% chose this)
  • The Second or Third Class Radiotelegraph license is modified to a higher class (40% chose this)
  • The lower grade is canceled. Only one unexpired radiotelegraph operator's certificate may be held at the same time (40% chose this)
  • Licensees are permitted to hold any number of radiotelegraph operator certificates at the same time (20% chose this)
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What is the DC plate voltage of a resistance-coupled amplifier state with a plate-supply voltage of 260 V, a plate current of 1 mA, and a plate load resistance of 100,000 ohms?
  • 160 V (33% chose this)
  • 100 V (33% chose this)
  • 200 V (0% chose this)
  • 60 V (33% chose this)
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Heat developed within a storage cell under charge or discharge conditions is caused by:
  • I2R losses (0% chose this)
  • Energy transfer due to chemical reactions (33% chose this)
  • A & B (50% chose this)
  • None of the above (17% chose this)
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Given a vacuum tube of the following characteristics: plate voltage 1000 V, plate current 127 ma, filament current 5.4 amp, mutual conductance 8000 microvolts, and amplification factor of 25. What is the correct volume of negative grid bias for Class B amplifier?
  • 40 V (0% chose this)
  • 50 V (67% chose this)
  • 30 V (33% chose this)
  • 60 V (0% chose this)
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The unit of electrical power is:
  • Watt (25% chose this)
  • Joule per second (25% chose this)
  • Both A & B (50% chose this)
  • None of the above (0% chose this)
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What is the proper procedure to conduct a radiotelegraph equipment test?
  • By transmitting "EI" on the test frequency as a warning that a test transmission is about to be made (40% chose this)
  • Sending a series of "VVV" followed by the call sign of the testing station at about 10 words-per-minute (20% chose this)
  • The test transmission may not proceed until all stations on frequency have signalled their consent (20% chose this)
  • The nearest public or private coast station must be notified of an impending test (20% chose this)
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Bleeder resistors are used in power supplies:
  • To improve the output voltage regulation (0% chose this)
  • They also discharge the filter capacitor when the power is turned off (20% chose this)
  • Either A or B (60% chose this)
  • None of the above (20% chose this)
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The presence of gas within a tube is indicated:
  • By a blue glow (50% chose this)
  • By a red glow (25% chose this)
  • By a yellow glow (0% chose this)
  • None of the above (25% chose this)
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Harmonic radiation from a transmitter may cause interference:
  • Where the fundamental signal cannot be heard because of "skip" (0% chose this)
  • In other shipboard equipment (50% chose this)
  • A & B (50% chose this)
  • None of the above (0% chose this)
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What is the IF of a superheterodyne receiver receiving on 1000 kHz and the mixing oscillator is tuned to 1500 kHz?
  • 500 kHz (25% chose this)
  • 2500 kHz (25% chose this)
  • 2000 kHz (0% chose this)
  • None of the above (50% chose this)
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The ratio of magnetic flux density to the field strength is known as:
  • Residual magnetism (0% chose this)
  • Permeability (25% chose this)
  • Reluctance (50% chose this)
  • None of the above (25% chose this)
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Keying a simple-oscillator type of emergency transmitter may be accomplished by:
  • Inserting the key in series with the primary of the high voltage plate transformer (25% chose this)
  • Inserting the key in parallel with the primary of the high voltage plate transformer (25% chose this)
  • Inserting the key in series with the final output to the antenna (0% chose this)
  • None of the above (50% chose this)
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The emission of electrons from a material due to the impact of high-velocity electrons on its surface is:
  • Primary electron emission (33% chose this)
  • Secondary emission (33% chose this)
  • Mimetic emission (17% chose this)
  • None of the above (17% chose this)
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Electromagnets are used in:
  • loudspeakers (0% chose this)
  • meters (25% chose this)
  • motors (0% chose this)
  • All of the above (75% chose this)
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While a vessel is at sea, how frequently must the auto-alarm be tested?
  • At least once ever 6 hours (0% chose this)
  • At least once ever 12 hours (20% chose this)
  • At least once ever 24 hours (60% chose this)
  • None of the above (20% chose this)
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What effect does a change in the dielectric constant of a capacitor dielectric material have upon the capacitance of a capacitor:
  • Capacity varies directly with the dielectric constant (60% chose this)
  • Capacity may fluctuate wildly (40% chose this)
  • There is no effect upon the capacitance (0% chose this)
  • None of the above (0% chose this)
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Operating conditions for determining that a tube is being used as a power detector:
  • Bias at about cutoff (0% chose this)
  • High input grid resistance (33% chose this)
  • Plate circuit rectification (0% chose this)
  • All of the above (67% chose this)
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A discharged storage battery of 3 cells has an open circuit voltage of 1.8 V per cell and an internal resistance of 0.1 ohm per cell. What voltage is needed to give an initial charging rate of 10 A?
  • 8.4 V (40% chose this)
  • 10 V (20% chose this)
  • 15 V (40% chose this)
  • 12.5 V (0% chose this)
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What should a station operator do before making a transmission?
  • Check transmitting equipment to be certain it is properly calibrated (0% chose this)
  • Except for the transmission of distress calls, determine that the frequency is not in use by monitoring the frequency before transmitting (100% chose this)
  • Ask if the frequency is in use (0% chose this)
  • Transmit a general notification that the operator wishes to utilize the channel (0% chose this)
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Emery cloth should never be used to clean the commutator of a motor or generator:
  • Because it contains particles which may lodge between commutator segments and cause short circuits (50% chose this)
  • Because it may polish the commutator too smooth for good brush contact (25% chose this)
  • Because it may decrease the insulating quality of its mica between the interpoles (0% chose this)
  • None of the above (25% chose this)
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Transmitting tube filaments should be maintained at recommended voltages:
  • To realize the greatest life-expectancy (0% chose this)
  • If the filament voltage is too low, the emission will be reduced and operation of the circuit may be adversely affected (50% chose this)
  • If the voltage is too high, the filament may burn out (0% chose this)
  • All of the above (50% chose this)
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What is the function of the balancing capacitor in a direction finder?
  • To maximize "antenna effect" and so obtain a sharper null point indication of direction (0% chose this)
  • To reduce the noise factor in the first IF (50% chose this)
  • To minimize "antenna effect" and so obtain a sharper null point indication of direction (50% chose this)
  • None of the above (0% chose this)
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What may be used to neutralize an acid electrolyte?
  • Ammonium hydroxide (0% chose this)
  • Baking soda (25% chose this)
  • Washing soda (0% chose this)
  • All of the above (75% chose this)
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At what time(s) are routine transmissions forbidden in the bands of 480 to 515 kHz?
  • Routine transmissions are forbidden in 480 to 515 kHz (0% chose this)
  • 480 to 515 kHz are out of the marine radio band (20% chose this)
  • Routine transmissions are forbidden during the international silent period (60% chose this)
  • None of the above (20% chose this)
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To double the resonant frequency of a resonant circuit:
  • Make C one third of its original value (0% chose this)
  • Make L and C both half their original values (50% chose this)
  • Decreasing the value of both L and C in any proportion so that their product will be one-half of the original values (25% chose this)
  • None of the above (25% chose this)
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If there is no resistance in either leg of a circuit with an inductance of 5 henrys in parallel with a capacitance of 1 microfarad, what is the equivalent impedance of the parallel network circuit?
  • Zero (40% chose this)
  • Infinite (20% chose this)
  • Median (0% chose this)
  • None of the above (40% chose this)
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What is the purpose of a speech amplifier in connection with the modulator of a transmitter?
  • Used to raise the gain of signal after filtering (0% chose this)
  • To raise the signal-to-noise ratio and the output voltage of microphones (75% chose this)
  • To feed the mixer where signal-to-noise ratio is raised (25% chose this)
  • To pre-amp the weaker of the two signals received (0% chose this)
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A regenerative receiver's operation is:
  • An incoming RF carrier is coupled into the tuned-grid circuit and applied to the grid (0% chose this)
  • It is then amplified in the usual manner. A controllable portion of the plate signal is coupled back into the grid circuit (25% chose this)
  • The coupled back signal is in phase with the original signal thus amplifying it and providing a greater output signal in the plate circuit (0% chose this)
  • All of the above (75% chose this)
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A liquid which is capable of conducting electricity, but undergoes decomposition while doing so is:
  • An electrolyte (50% chose this)
  • A ferromagnetic material under the influence of a magnetizing force (50% chose this)
  • Equal to the ohmic resistance of the circuit (0% chose this)
  • None of the above (0% chose this)
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If a motor generator fails to start when the start button is depressed, the trouble may be:
  • Blown fuse or tripped circuit breaker (0% chose this)
  • Open armature or motor-field rheostat (75% chose this)
  • Broken connections, defective brushes (0% chose this)
  • All of the above (25% chose this)
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2182 kHz is the international radiotelephone distress frequency. It is also used for a calling channel. The authorized mode of emission is H3E (single-sideband full carrier). A3E (double-sideband full carrier) is only authorized for equipment:
  • Solely intended for distress and safety communications (40% chose this)
  • Built and sold after the GMDSS implementation date (20% chose this)
  • Built and sold before the GMDSS implementation date (40% chose this)
  • Solely intended for ship-to-shore public correspondence (0% chose this)
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When the current sine wave in a circuit reaches its peak value before the voltage wave:
  • It is said to have a leading power factor (25% chose this)
  • It is said to have a lagging power factor (25% chose this)
  • It is said to be in phase (25% chose this)
  • None of the above (25% chose this)
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The condition of a dry "B" battery may be determined:
  • By measuring the voltage under normal load (0% chose this)
  • By measuring the voltage under no load (25% chose this)
  • A loss of 20 % of the voltage under normal load indicates that the battery should be replaced (0% chose this)
  • A & C (75% chose this)
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The minimum power dissipation rating of a resistor of 20,000 ohms across a potential of 500 V should be:
  • 25 watts (25% chose this)
  • 12.5 watts (75% chose this)
  • 15 watts (0% chose this)
  • None of the above (0% chose this)
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A relay coil has 500 ohms resistance, and operates on 125 mA. What value of resistance should be connected in series with it to operate from 110 VDC?
  • 380 ohms (0% chose this)
  • 400 ohms (50% chose this)
  • 200 ohms (50% chose this)
  • None of the above (0% chose this)
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What effect would insufficient radio-frequency excitation have on Class C modulated amplifier output?
  • A negative carrier shift (40% chose this)
  • A positive carrier shift (20% chose this)
  • Both A and B (20% chose this)
  • None of the above (20% chose this)
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The total power dissipation capability of two 10 watt, 500 ohm resistors connected in series is:
  • 20 watts (33% chose this)
  • 10 watts (67% chose this)
  • 5 watts (0% chose this)
  • None of the above (0% chose this)
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When the relative amplitudes of the positive and negative modulation peaks are unsymmetrical:
  • Carrier shift (0% chose this)
  • Frequency shift (50% chose this)
  • Amplifier shift (50% chose this)
  • None of the above (0% chose this)
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A circuit passes 3 A. The internal resistance of the source is 2 ohms. The total resistance is 50 ohms. What is the terminal voltage of the source?
  • 150 V (20% chose this)
  • 100 V (20% chose this)
  • 110 V (40% chose this)
  • 240 V (20% chose this)
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Can a transformer be used with direct current?
  • In general, no (0% chose this)
  • If the DC current is periodically interrupted it would be possible to use an original DC voltage source (33% chose this)
  • Both A and B (67% chose this)
  • None of the above (0% chose this)
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What transmission should precede the transmission of the distress call?
  • The distress call, when sent in radiotelegraph on 500 kHz shall as a general rule, be immediately preceded by the auto-alarm signal (0% chose this)
  • SOS should be sent three times (60% chose this)
  • The words "MAY DAY" should be sent three times (20% chose this)
  • None of the above (20% chose this)
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Describe how a distress call should be made:
  • The distress call should be made three times (0% chose this)
  • SOS should be called twice (25% chose this)
  • The distress call shall include the distress signal transmitted three times, the word DE, and the call signal of the mobile station in distress transmitted three times (75% chose this)
  • None of the above (0% chose this)
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What is the maximum permissible RMS value of audio voltage which can be applied to the grid of a Class A audio amplifier which has a grid bias of 10 V?
  • 7.07 V (25% chose this)
  • 8 V (25% chose this)
  • 10 V (0% chose this)
  • 14.14 V (50% chose this)
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Characteristics of a vacuum tube operating as a class A amplifier:
  • Low plate circuit efficiency, about 25%; practically no grid driving power; plate current flowing for 360 degrees of each cycle; practically no distortion of the output waveshape (17% chose this)
  • Plate circuit efficiency, about 50-60%; plate current flows slightly more than 180 degrees of each cycle, medium power output (33% chose this)
  • High efficiency, up to 80%; plate current drawn in bursts; great distortion of output waveshape (50% chose this)
  • None of the above (0% chose this)
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The follow devices that could be used to indicate oscillation in a crystal oscillator are:
  • Plate DC milliammeter, grid DC ammeter, neon bulb (0% chose this)
  • Thermogalvanometer, wavemeter (20% chose this)
  • Flashlight bulb on a loop of wire, heterodyne type frequency meter (20% chose this)
  • All of the above (60% chose this)
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What types of meters may be used to measure RF currents?
  • The hot wire ammeter (0% chose this)
  • The thermocouple ammeter (25% chose this)
  • Both A & B (75% chose this)
  • None of the above (0% chose this)
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The ratio of peak-to-effective voltage values of a sign wave are:
  • 1.414 to 1 (0% chose this)
  • 1 to 0.707 (25% chose this)
  • Both A and B (75% chose this)
  • Neither A or B (0% chose this)
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Upon what band, in addition to the 350 to 515 kHz band must a main receiver on a United States ship be capable of operation?
  • 600 TO 700 kHz (0% chose this)
  • 1000 TO 1200 kHz (100% chose this)
  • 100 TO 200 kHz (0% chose this)
  • 516 TO 615 kHz (0% chose this)
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A minute subdivision of matter having the smallest known unit of negative electrical charge is:
  • Electron (33% chose this)
  • Ion (33% chose this)
  • Gilbert (0% chose this)
  • Joule (33% chose this)
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The average fully-charged voltage of an Edison storage cell is:
  • 1.2 V (0% chose this)
  • 1.5 V (50% chose this)
  • 2 V (25% chose this)
  • 1 V (25% chose this)
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Between what points on a ship, compulsorily equipped with a radiotelegraph installation, is a reliable intercommunication system required?
  • Between the forward bridge and the radio room (0% chose this)
  • Between the radio room and engineering (33% chose this)
  • Between the radio room and the navigation bridge (67% chose this)
  • None of the above (0% chose this)
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The tops of lead-acid batteries should be kept dry:
  • To prevent slow discharge of the battery (0% chose this)
  • To prevent terminal overload (20% chose this)
  • To reduce the formation of terminal corrosion (20% chose this)
  • A & C (60% chose this)
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What is the resonant frequency of a tuned circuit consisting of a 500 picofarad capacitor, a 150 microfarad tuning coil, and 10 ohms resistance?
  • 581 kHz (33% chose this)
  • 753 kHz (67% chose this)
  • 498 kHz (0% chose this)
  • None of the above (0% chose this)
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The most desirable factor in the choice of a vacuum tube for a voltage amplifier:
  • A low value of transconductance (0% chose this)
  • A high value of transconductance (25% chose this)
  • High output tube capacitance (50% chose this)
  • None of the above (25% chose this)
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The ratio of current through a conductor to the voltage which produces it is:
  • Inductance (20% chose this)
  • Conductance (40% chose this)
  • Resistance (40% chose this)
  • None of the above (0% chose this)
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Good insulators at radio frequencies are:
  • Pyrex, mica (0% chose this)
  • Isolantite, steatite, polyethylene (20% chose this)
  • Rubber, porcelain (40% chose this)
  • A & B (40% chose this)
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A transmitter has a master-oscillator, intermediate amplifier, and final amplifier. In what order should the circuit be adjusted in putting the transmitter in operation?
  • Master-oscillator, intermediate amplifier, final amplifier, antenna circuit (50% chose this)
  • Antenna circuit, master-oscillator, intermediate amplifier, final amplifier (50% chose this)
  • Final amplifier, antenna circuit, master-oscillator, intermediate amplifier (0% chose this)
  • Master-oscillator, intermediate amplifier, antenna circuit, final amplifier (0% chose this)
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What disadvantage is there to a dynamotor?
  • Compactness (0% chose this)
  • Operating efficiency (100% chose this)
  • It can be operated from batteries (0% chose this)
  • Its output voltage is dependent on the source voltage stability (0% chose this)
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What effect will high coupling between the plate and grid circuits of a quartz-crystal oscillator have?
  • The grid to plate capacitance will be destroyed (0% chose this)
  • The oscillation will be higher because of higher Q (0% chose this)
  • Overheating of the crystal and possible breakage (60% chose this)
  • Overmodulation (40% chose this)
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What is the total reactance of a series AC circuit, with no resistance and equal inductance and capacitive reactances?
  • The two reactances cancel being equal and opposite (0% chose this)
  • Net impedance is purely resistive and contains no reactive component (0% chose this)
  • The total reactance is zero at the resonant frequency (25% chose this)
  • All of the above (75% chose this)
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An Edison storage battery should not be charged at less than the manufacturer's specified rate:
  • In order that the capacity of the battery shall be maximum after charge (0% chose this)
  • The chemical reactions of the Edison-type cell (0% chose this)
  • A & B (100% chose this)
  • None of the above (0% chose this)
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What would be the dB change in field intensity at a given distance if the power is doubled?
  • 3 dB (20% chose this)
  • 6 dB (40% chose this)
  • 2 dB (20% chose this)
  • 10 dB (20% chose this)
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The condition of charge of an Edison cell can be determined:
  • By reading the terminal voltage under load (0% chose this)
  • By checking the voltage against a standard discharge curve (20% chose this)
  • Both A & B (80% chose this)
  • Checking the specific gravity (0% chose this)
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What is meant by split tuning?
  • An effect resulting from excessive coupling between two tuned circuits which are at the same frequency (0% chose this)
  • Also known as double hump (25% chose this)
  • Also known as critical coupling (25% chose this)
  • Both A and B (50% chose this)
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Upon compulsorily equipped vessels which are required to have an accurate clock in the radio room, how frequently must this clock be adjusted and be compared with standard time?
  • Every three hours (0% chose this)
  • Ever four hours (0% chose this)
  • Every six hours (20% chose this)
  • At least once every 24 hours (80% chose this)
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A dynamotor is:
  • A combination motor-generator which utilizes a common field winding (20% chose this)
  • Usually run by battery power (20% chose this)
  • A higher efficiency than a motor-generator (0% chose this)
  • All of the above (60% chose this)
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The diameter of a conductor six inches long is doubled, what will be the effect on the resistance?
  • One-fourth the original value (0% chose this)
  • One-half the original value (67% chose this)
  • The resistance varies inversely with the cross-sectional area of the conductor (0% chose this)
  • A & C (33% chose this)
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How could you test a regenerative receiver to determine if the detector is oscillating?
  • Touch a finger on grounded wire to the grid circuit. You will hear a "plop" if the circuit was oscillating (0% chose this)
  • Vary the regeneration control to its maximum limits. You will hear a "plop" as the circuit goes in and out of oscillation (20% chose this)
  • Either A or B (80% chose this)
  • None of the above (0% chose this)
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If you receive a distress call signed by a call signal composed of five letters, could you determine the type of craft which transmitted the signal?
  • Five letter call signals are assigned to aircraft stations (0% chose this)
  • Three letter call signals are assigned to land stations (20% chose this)
  • Four letter call signals are assigned to ship stations (20% chose this)
  • All of the above (60% chose this)
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In a self-biased RF amplifier stage: plate voltage is 1250 V, plate current 150 ma, grid current 15 ma, grid-leak resistance of 4000 ohms, what is the operating grid bias?
  • 60 V (25% chose this)
  • 30 V (0% chose this)
  • 90 V (75% chose this)
  • 50 V (0% chose this)
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High IF frequencies in a superheterodyne receiver:
  • Reduce image frequency response (0% chose this)
  • Increases image frequency response (50% chose this)
  • Places the image frequency as close as possible to the normal received frequency (50% chose this)
  • None of the above (0% chose this)
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This partially counteracts the line voltage and so limits the armature current in a DC motor:
  • EMF (25% chose this)
  • Counter EMF (25% chose this)
  • Opposition EMF (25% chose this)
  • None of the above (25% chose this)
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In what types of circuits do beam power vacuum tubes find application?
  • As audio amplifier in the output and power stages of circuits having low to moderately high output ratings (0% chose this)
  • As an RF power amplifier (25% chose this)
  • Both A & B (75% chose this)
  • None of the above (0% chose this)
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Loose laminations in a filter choke:
  • Make it impossible to firmly connect the choke in a circuit (0% chose this)
  • A & C (50% chose this)
  • Cause a buzzing or chattering sound (33% chose this)
  • None of the above (17% chose this)
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Resistance is:
  • The quantity which determines power loss or dissipation (0% chose this)
  • The factor of proportionality between voltage and current (40% chose this)
  • Measured in ohms (0% chose this)
  • All of the above (60% chose this)
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In an RF amplifier with fixed bias, as the plate circuit is varied from below resonance to above resonance, what will the grid current do?
  • The grid current will rise slightly at resonance (25% chose this)
  • The grid current will dip slightly at resonance (50% chose this)
  • The grid current will not vary (0% chose this)
  • None of the above (25% chose this)
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When hoisting a shipboard antenna, to avoid damage to the wire and insulators:
  • Avoid bending the wire (0% chose this)
  • Avoid smashing the insulators against metal objects (33% chose this)
  • A and B (67% chose this)
  • None of the above (0% chose this)
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The efficiency of a radio device is:
  • The ratio of the power input to the power output (0% chose this)
  • The ratio of the useful power output to the power input (50% chose this)
  • The ratio of the minimum power output to the maximum power output (33% chose this)
  • None of the above (17% chose this)
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What examination credit is accorded Amateur Extra Class operators?
  • 20 code groups and 25 text words per minute (0% chose this)
  • Amateur radio operators are not eligible for commercial radio operator examination credit (75% chose this)
  • Commercial radio operator telegraphy Elements 1 and 2 (25% chose this)
  • Written Element 1, basic radio law and operating practices (0% chose this)
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One horsepower is:
  • 746 Watts (33% chose this)
  • Roughly 3/4 kilowatt (0% chose this)
  • Corresponds to lifting 550 pounds at the rate of one foot per second (0% chose this)
  • All of the above (67% chose this)
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Why is an oscillator crystal operated at a constant temperature?
  • Just because, stupid! (0% chose this)
  • To maintain a constant frequency output from the oscillator (50% chose this)
  • Constant temperature allows easier frequency change (0% chose this)
  • None of the above (50% chose this)
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The D'Arsonval type meter consists of:
  • A permanent magnet, a movable coil with pointer attached rotating in jewel bearing (0% chose this)
  • A movable coil with pointer attached rotating in jewel bearings, and two spiral springs (one on each side of the removable coil) (25% chose this)
  • A & B (50% chose this)
  • None of the above (25% chose this)
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Most receiver hiss is due to:
  • Noise generated in the first detector (75% chose this)
  • Noise generated in the first AF amplifier (0% chose this)
  • Faulty regeneration control (0% chose this)
  • None of the above (25% chose this)
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The formula for determining the wavelength when the frequency is known is:
  • Wavelength = 300,000/ f kHz (0% chose this)
  • Wavelength = 300,000,000/ f Hz (20% chose this)
  • Wavelength = 300/ f MHz (0% chose this)
  • All of the above (80% chose this)
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Two effects of over-excitation of a Class B amplifier grid circuit are:
  • Increased plate efficiency, decreased power output (0% chose this)
  • Decreased plate efficiency, excessive grid current (0% chose this)
  • Excessive plate current, excessive distortion (25% chose this)
  • Both B and C (75% chose this)
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The charge of electricity which passes a given point in one second when a current of one ampere is flowing is:
  • Coulomb (0% chose this)
  • Joule (67% chose this)
  • Watt (0% chose this)
  • None of the above (33% chose this)
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The motor-field rheostat should be ____ when starting a DC motor generator set:
  • Minimum resistance in the armature circuit (40% chose this)
  • Minimum resistance in the field circuit (40% chose this)
  • Maximum resistance in the field circuit (0% chose this)
  • None of the above (20% chose this)
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The buffer amplifier stage of a transmitter:
  • To hold any discriminator signals until verified by the varactor diode circuits (0% chose this)
  • Buffers any signals that may have been imposed upon the carrier signal (0% chose this)
  • To improve the frequency stability of the oscillator (33% chose this)
  • Both A and C (67% chose this)
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Tubes operated as Class C amplifiers are not suited for audio-frequency amplifiers:
  • Because of excessive distortion (50% chose this)
  • Because of current requirement (0% chose this)
  • Because of reduced life expectancy of the filament (25% chose this)
  • None of the above (25% chose this)
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When using and storing crystal microphones:
  • They should be protected from shock and vibration (0% chose this)
  • They should be protected from humidity (0% chose this)
  • They should be protected from high temperatures (20% chose this)
  • All of the above (80% chose this)
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When may a public coast station authorized to use high frequency narrow-band direct-printing (NB-DP) establish contact with a ship station using telegraphy?
  • Never. Contact may only be established using NB-DP circuits (50% chose this)
  • When the ship is in excess of 300 gross tons (0% chose this)
  • When the radio station license reflects authority for this type of operation and harmful interference is avoided (50% chose this)
  • When it is known that the vessel does not have a selective ringing or calling device (0% chose this)
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In what city is the major telecommunication center of the United States located?
  • Houston (0% chose this)
  • New York City (50% chose this)
  • Washington (50% chose this)
  • Chicago (0% chose this)
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Within what frequency band limits do all United States marine radio beacon stations operate?
  • From 280 to 385 kHz (0% chose this)
  • From 162 to 385 kHz (50% chose this)
  • From 285 to 315 kHz (25% chose this)
  • From 300 to 465 kHz (25% chose this)
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Low plate current may be caused by:
  • Low filament emission and voltage (0% chose this)
  • Excessive bias value, shorted screen by-pass capacitor (0% chose this)
  • Open grid circuit, low screen grid supply voltage (33% chose this)
  • All of the above (67% chose this)
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What is the total capacitance of the capacitors of 3, 5, and 7 microfarad connected in series?
  • 14.79 microfarad (33% chose this)
  • 1.479 microfarad (0% chose this)
  • 15 microfarad (33% chose this)
  • None of the above (33% chose this)
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How is power output of a transmitter adjusted?
  • It should radiate the minimum power necessary to insure reliable communications (0% chose this)
  • It may be controlled by varying the plate supply (0% chose this)
  • Both A and B (100% chose this)
  • None of the above (0% chose this)
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Where must ship station logs be kept during a voyage?
  • They must be secured in the vessel's strongbox for safekeeping (0% chose this)
  • In the personal custody of the licensed commercial radio operator (0% chose this)
  • At the principal radiotelephone operating position or radiotelegraph operating room (75% chose this)
  • All logs are turned over to the ship's master when the radio operator goes off duty (25% chose this)
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The total bandwidth of a transmitter using A-2 emission with a modulating frequency of 800 Hz and a carrier frequency of 500 kHz is:
  • 1600 Hz (33% chose this)
  • 1.6 kHz (33% chose this)
  • 800 kHz (33% chose this)
  • 1000 kHz (0% chose this)
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How would you determine the cathode bias resistance necessary to provide correct grid bias for an amplifier?
  • Bias is equal to IR drop across the cathode resistance (25% chose this)
  • Measure with a regular multimeter (0% chose this)
  • Both A & B (50% chose this)
  • None of the above (25% chose this)
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What current will flow in a 6 V storage battery with an internal resistance of 0.01 ohms, when a 3 W, 6 V lamp is connected?
  • 0.4995 A (67% chose this)
  • 0.4885 A (0% chose this)
  • 0.5566 A (33% chose this)
  • 0.5795 A (0% chose this)
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The wavelength of the period of one complete cycle of a radio wave of 0.000,001 second is:
  • 300 M (20% chose this)
  • 3000 M (0% chose this)
  • 30 M (40% chose this)
  • 70 cm (40% chose this)
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What capacity in amperes of storage battery is required to operate a 50 W emergency transmitter for 6 hr.? Assume a continuous transmitter load of 70% of the key-locked demand of 40 A, and an emergency light load of 1.5 A.
  • A battery rated greater than 177 amperhours (0% chose this)
  • A battery rated at least 177 amperhours (0% chose this)
  • A & B (67% chose this)
  • None of the above (33% chose this)
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A tuned circuit made up of inductance and capacitance is:
  • An oscillator (60% chose this)
  • A neutralizer (20% chose this)
  • Voltage divider (20% chose this)
  • None of the above (0% chose this)
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Why is correct grid bias necessary for audio frequency amplifier?
  • To minimize distortion (40% chose this)
  • To set the operating conditions for determining the class of amplifications (0% chose this)
  • So as not to exceed the rated plate dissipation of the tube (0% chose this)
  • All of the above (60% chose this)
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What may cause sulfation of a lead-acid cell?
  • It is a normal process (25% chose this)
  • Overdischarging (0% chose this)
  • Local action with improper charging (25% chose this)
  • All of the above (50% chose this)
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With an auto alarm that uses a square-law detector and a mechanical selector what causes the bell to ring?
  • Receipt of the true auto-alarm signal, low battery voltage (0% chose this)
  • Filament circuit open, the 24 V circuit to receiver open (0% chose this)
  • Battery charger fuse blown, motor stopped or running (0% chose this)
  • All of the above (100% chose this)
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Advantages of capacitor input and choke-input filters when used with rectifiers:
  • Capacitor-input filter provides higher output voltage under reasonably light load conditions (0% chose this)
  • Choke-input filter offers better voltage regulations (0% chose this)
  • A & B (80% chose this)
  • None of the above (20% chose this)
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An electrical potential may be generated by:
  • Varying a magnetic field through a circuit (0% chose this)
  • Chemical action (0% chose this)
  • Photo-electric action (0% chose this)
  • All of the above (100% chose this)
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Efficiency of a power transformer is determined by:
  • Eddy current losses (0% chose this)
  • Hysteresis losses (0% chose this)
  • Copper losses (25% chose this)
  • All of the above (75% chose this)
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How would you determine the cathode-bias resistance necessary to provide correct grid bias for an amplifier?
  • Bias equals the IR drop across the cathode (0% chose this)
  • Bias is found by dividing the desired DC bias voltage by the total no-signal cathode current (0% chose this)
  • For a tetrode or pentode, the screen current must be added to the plate current (25% chose this)
  • All of the above (75% chose this)
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The total inductance of two coils in parallel without any mutual coupling is:
  • Equal to the product of the two inductances divided by their sum (0% chose this)
  • The sum of the individual inductances (33% chose this)
  • Zero (0% chose this)
  • None of the above (67% chose this)
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A transmitter operating on 5000 kHz uses a 1000 kHz crystal with a tempered coefficient of - 4 Hz/MHz/0 degrees centigrade. What is the change in the output frequency of the transmitter if the temperature increases 6 degrees centigrade?
  • 499.88 kHz (0% chose this)
  • 5000.12 kHz (0% chose this)
  • 4120.0 kHz (0% chose this)
  • 5120.0 kHz (100% chose this)
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Noisy operation of a regenerative, 3-circuit receiver with two stages of AF amplification may be caused by:
  • Defective tubes, poor connections (0% chose this)
  • Defective audio transformers (0% chose this)
  • Defective grid resistance of grid-capacitor, or defective elements in the power supply (0% chose this)
  • All of the above (100% chose this)
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What is voltage regulation as applied to power supplies?
  • The ratio of change in voltage between no load and full load to the full-load voltage output (50% chose this)
  • The ratio of output to input voltage (25% chose this)
  • Voltage output of the power supply under full load (0% chose this)
  • The ratio of input to output voltage (25% chose this)
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Primary cells:
  • Can be recharged (20% chose this)
  • Cannot be recharged (20% chose this)
  • An attempt to recharge it would not restore the eroded electrode (0% chose this)
  • B & D (60% chose this)
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Advantages of high-frequency radio communication:
  • The upper frequencies are substantially free of atmospheric interference, small antennas permit efficient mobile operation (0% chose this)
  • Man-made noises are no problem, reflections may easily occur from buildings and other objects (0% chose this)
  • A & B (50% chose this)
  • None of the above (50% chose this)
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Which method may be used to obtain more than one value of voltage from a fixed DC source?
  • Use a resistance type voltage divider (0% chose this)
  • Connect voltage regulator tubes of suitable values and tap off the desired output voltage (0% chose this)
  • Both A & B (67% chose this)
  • None of the above (33% chose this)
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Even harmonics may be reduced in the output of an audio frequency amplifier:
  • By operating the state push-pull (0% chose this)
  • In a single tube amplifier, by operating the stage only on the linear part of the tube's characteristic curve (33% chose this)
  • A & B (33% chose this)
  • None of the above (33% chose this)
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If a resistance to which a constant voltage is applied is halved, what power dissipation will result?
  • Doubled (75% chose this)
  • Halved (0% chose this)
  • Tripled (25% chose this)
  • Same (0% chose this)
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How should a radar set be adjusted by the operator to reduce "sea return"?
  • Rotate the antenna for a deep null (0% chose this)
  • Reduce the gain control (33% chose this)
  • The operator should manually adjust the "suppressor" control or sensitivity time control, STC (33% chose this)
  • None of the above (33% chose this)
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Given: Input power to a receiver is 75 watts. How much power does the receiver consume in 24 hours of continuous operation?
  • 1800 watthours (0% chose this)
  • 1.80 kilowatthours (0% chose this)
  • A & B (100% chose this)
  • None of the above (0% chose this)
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C = capacity in farads. Q = the measure of the quantity of charge of electricity in Coulombs. E = the applied voltage. So Q = CE:
  • Determines the quantity of charge in a capacitor (0% chose this)
  • Determines the Q of a circuit (0% chose this)
  • Both A & B (67% chose this)
  • None of the above (33% chose this)
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The unit of inductance is:
  • Henry (50% chose this)
  • Joule (0% chose this)
  • Coulomb (50% chose this)
  • Ohm (0% chose this)
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What is the reactance of a 2-henry choke at 3000 Hz?
  • 5300 ohms (50% chose this)
  • 37,680 ohms (50% chose this)
  • 376,800 ohms (0% chose this)
  • 53,000 ohms (0% chose this)
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What care should be taken with selecting water to add to a storage cell?
  • It should be chemically pure or distilled (67% chose this)
  • It should be only sea water (33% chose this)
  • Tap water is as good as any (0% chose this)
  • None of the above (0% chose this)
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What modulation is contained in static and lightning radio waves?
  • All odd harmonic frequencies (0% chose this)
  • All even harmonic frequencies (25% chose this)
  • Amplitude modulation (50% chose this)
  • Frequency modulation (25% chose this)
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The prefix " kilo " means:
  • To multiply by 1000 whatever quantity follows (50% chose this)
  • To divide by 1000 whatever quantity follows (0% chose this)
  • To add 1000 to whatever quantity follows (25% chose this)
  • None of the above (25% chose this)
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By-pass capacitors are often connected across the brushes of a high-voltage DC generator:
  • To regulate the voltage (0% chose this)
  • To protect the generator winding from high voltage surges (25% chose this)
  • To reduce RF interference (25% chose this)
  • B & C (50% chose this)
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If a vacuum tube with a filament rating of 0.25 A and 5 V is operated from a 6 volt battery, what value of resistor is necessary?
  • 4 ohms (25% chose this)
  • 5 ohms (25% chose this)
  • 10 ohms (0% chose this)
  • 2 ohms (50% chose this)
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An "harmonic" is:
  • A whole multiple of an original frequency (67% chose this)
  • The heating value of an RF current (0% chose this)
  • The internal impedance of a power source (17% chose this)
  • A multiple of the power factor (17% chose this)
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Given the following: (1) audio power for 100% modulation equals 50% of DC input power to RF modulated amplifier, (2) load presented to the modulated tube consists of the DC plate impedance of the modulated amplifier, (3) constant grid excitation voltage, very lot distortion, what type of modulation?
  • Grid (33% chose this)
  • Plate (33% chose this)
  • Cathode (0% chose this)
  • Anode (33% chose this)
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A superheterodyne receiver may not successfully be used for reception of frequencies very near the IF frequency:
  • Because those near frequencies would pass directly through the IF amplifier and not be greatly affected by the tuning of the RF or oscillator stages (67% chose this)
  • Because those near frequencies would not pass directly through the IF amplifier (0% chose this)
  • Because those near frequencies would be greatly affected by the tuning of the RF or oscillator stages (33% chose this)
  • None of the above (0% chose this)
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When connecting electrolytic capacitors in series:
  • Observe the polarity marked on the component (25% chose this)
  • There is no polarity to observe (75% chose this)
  • Connect anode to anode (0% chose this)
  • Connect cathode to cathode (0% chose this)
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What is are the advantages of self excited oscillator and master-oscillator power-amplifier transmitters?
  • The master-oscillator has fewer parts than the self-excited and is simpler to construct (0% chose this)
  • The self-excited oscillator transmitter is simpler to construct and has fewer parts than the master-oscillator (0% chose this)
  • Either A or B (100% chose this)
  • Neither (0% chose this)
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A 500 Hz AC plate supply, rectified by a full-wave, unfiltered rectifier circuit. What would the emission be?
  • A modulated continuous wave of 500 Hz (0% chose this)
  • A modulated continuous wave of 1000 Hz (33% chose this)
  • A-2 (0% chose this)
  • All of the above (67% chose this)
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The sum of all voltage drops around a simple DC circuit, including the source, is:
  • Zero (50% chose this)
  • Insignificant (0% chose this)
  • Infinite (0% chose this)
  • None of the above (50% chose this)
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Who may program authorized frequency channels into a transmitter or transceiver used in the maritime service?
  • Any person who has the authorization of the station licensee or ship's master (20% chose this)
  • A licensed marine radio operator or higher (40% chose this)
  • A person holding a restricted radiotelephone operator permit or higher (20% chose this)
  • Only persons holding a first or second class radiotelegraph operator's certificate or a general radiotelephone operator's license (20% chose this)
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How may polarity of a storage battery be determined?
  • Voltmeter (0% chose this)
  • Salt water method (0% chose this)
  • A & B (100% chose this)
  • None of the above (0% chose this)
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A 20 ohm resistor with a current of 0.25 A passing through it will dissipate how many watts?
  • 10 watts (0% chose this)
  • 20 watts (33% chose this)
  • 0.025 watts (33% chose this)
  • 1.25 watts (33% chose this)
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A transformer has a primary voltage of 100, primary turns = 200, and secondary turns = 40. What is the secondary voltage?
  • 20 V (25% chose this)
  • 240 V (25% chose this)
  • 140 V (25% chose this)
  • 340 V (25% chose this)
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The product of the readings of an AC voltmeter and ammeter in an AC circuit is called what?
  • Reverse power (0% chose this)
  • Apparent power (67% chose this)
  • Current power (33% chose this)
  • None of the above (0% chose this)
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What is the international radiotelegraph distress frequency for stations in the mobile service?
  • 300 kHz (0% chose this)
  • 400 kHz (50% chose this)
  • 500 kHz (50% chose this)
  • 600 kHz (0% chose this)
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Which class of amplifier is used in the final amplifier stage for maximum plate efficiency?
  • Class A (33% chose this)
  • Class B (33% chose this)
  • Class C (33% chose this)
  • Filtered Class D (0% chose this)
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An audio-transformer is seldom used as the output device in the plate circuit of a tetrode audio-amplifier stage:
  • Because an ordinary transformer cannot supply enough impedance to the plate circuit (67% chose this)
  • Because an ordinary transformer supplies too much impedance to the plate circuit (33% chose this)
  • Because an ordinary transformer would be too costly (0% chose this)
  • None of the above (0% chose this)
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By-pass capacitors across the cathode-bias resistors of an RF amplifier:
  • Prevent variations of bias during excitation of the amplifier (0% chose this)
  • Results in better gain of the amplifier stage (33% chose this)
  • A & B (67% chose this)
  • None of the above (0% chose this)
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Materials frequently used for relay contacts:
  • Tungsten (0% chose this)
  • Silver (25% chose this)
  • Gold (0% chose this)
  • All of the above (75% chose this)
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Frequencies with substantially line propagations:
  • VHF, UHF, microwave (25% chose this)
  • About 50-30,000 MHz (25% chose this)
  • A & B (50% chose this)
  • None of the above (0% chose this)
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The negative plate of an Edison-type storage cell is:
  • Finely powdered pure iron (20% chose this)
  • Green oxide of nickel (40% chose this)
  • Potassium oxide (20% chose this)
  • None of the above (20% chose this)
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Adding a capacitor in series with an antenna will have what effect on resonant frequency?
  • Decrease (67% chose this)
  • Increase (0% chose this)
  • Neutralization (33% chose this)
  • Equalization (0% chose this)
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Causes of excessive sparking at the brushes of a DC motor or generator include:
  • Brushes not properly set at neutral point, dirt on commutator, motor overloaded (0% chose this)
  • Weak spring tension on brushes, brushes worn, commutator worn eccentric (0% chose this)
  • High mica-insulation between bars, commutator bars of uneven height (0% chose this)
  • All of the above (100% chose this)
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A properly operated Class A audio amplifier:
  • Produces no serious modification of the input waveform (33% chose this)
  • Serious distortion is present (0% chose this)
  • A & B (67% chose this)
  • All of the above (0% chose this)
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What document is issued after a radio station inspection aboard a large ship that is not a passenger vessel?
  • Great Lakes Radio Agreement surety authorization (0% chose this)
  • International Maritime Organization safety permit (25% chose this)
  • Cargo ship safety radiotelegraphy or radiotelephony certificate (25% chose this)
  • Safety Convention radio certification (50% chose this)
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A purplish glow from within a tube indicates:
  • A soft tube (0% chose this)
  • A hard tube (0% chose this)
  • Air or undesired gases within the tube (100% chose this)
  • A & C (0% chose this)
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How may the power in a AC circuit be determined?
  • The power in an AC circuit may be determined by a wattmeter (0% chose this)
  • By multiplying the product of the circuit voltage and current by the power factor (0% chose this)
  • Both answers A & B (100% chose this)
  • None of the above (0% chose this)
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Why is rosin used as a soldering flux?
  • It is noncorrosive (0% chose this)
  • It allows a perfect soldering bond to be made (0% chose this)
  • It possesses good insulation qualities (25% chose this)
  • All of the above (75% chose this)
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Radio frequencies that are useful for long distance communications requiring continuous operation:
  • Low frequency (33% chose this)
  • High frequency (67% chose this)
  • Very high frequency (0% chose this)
  • Ultra high frequency (0% chose this)
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Normal undistorted modulation is indicated by:
  • An increase in antenna current without carrier shift (67% chose this)
  • A decrease in antenna current without carrier shift (33% chose this)
  • An increase in antenna current with carrier shift (0% chose this)
  • A decrease in antenna current with carrier shift (0% chose this)
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Explain the use and meaning of the following indicator or prefix "RP" on radiotelegrams:
  • Please reply (67% chose this)
  • Repeat following parts of message (33% chose this)
  • "Reply paid" (0% chose this)
  • None of the above (0% chose this)
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In a self excited oscillator, a swinging antenna:
  • Will cause serious frequency instability (67% chose this)
  • Will cause no noticeable frequency instability (33% chose this)
  • May cause minor frequency instability (0% chose this)
  • None of the above (0% chose this)
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The difference between electrical power and electrical energy is:
  • Electrical power is the rate of doing work by electricity (0% chose this)
  • Electrical energy is the ability to accomplish work by electricity (0% chose this)
  • A & B (100% chose this)
  • None of the above (0% chose this)
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To reduce the sparking at the contacts of a key used in a radiotelegraph transmitter:
  • Connect a suitable key-click filter across the key (75% chose this)
  • Connect a suitable key-click filter in series with the key (0% chose this)
  • Connect a suitable high-pass filter across the key (25% chose this)
  • Increase the contact space of the key (0% chose this)
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The term cathode ray usually applies to:
  • A fairly high velocity electron beam (67% chose this)
  • Background noise (0% chose this)
  • The logarithm gain of an electron beam (33% chose this)
  • None of the above (0% chose this)
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Image response may be minimized in a superheterodyne receiver:
  • By using one or more tuned RF stages ahead of the mixer (0% chose this)
  • By choosing a suitable IF (such that the image frequency will fall within the receiver's operating range) (0% chose this)
  • By choosing a suitable IF (such that the image frequency will fall outside of the receiver's operating range) (0% chose this)
  • A & C (100% chose this)
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Why suppress RF harmonics in the output of a transmitter?
  • To prevent interference from occurring with other radio services (50% chose this)
  • To restrict the bandwidth of the particular station to the legal limits (0% chose this)
  • Both A & B (50% chose this)
  • None of the above (0% chose this)
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Why do headphones usually have high-impedance windings?
  • They can usually be operated without an impedance matching transformer (0% chose this)
  • They represent a closer match to the plate load impedance for the tube delivering necessary driving power than low impedance planes (0% chose this)
  • A & B (100% chose this)
  • None of the above (0% chose this)
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What will be the effect of a small increase in the number of turns upon the field strength of a single layer solenoid?
  • Decrease in field strength if the coil length is increased (0% chose this)
  • Unchanged if the spacing is reduced to keep the length constant (0% chose this)
  • Both A and B (100% chose this)
  • None of the above (0% chose this)
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Audio howl may be caused by:
  • A "fringe" setting of the regeneration control (0% chose this)
  • A defective tube (0% chose this)
  • An open grid resistor (0% chose this)
  • All of the above (100% chose this)
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Increasing the number of plates of a capacitor:
  • Will increase the capacitance (50% chose this)
  • Will decrease the capacitance (0% chose this)
  • Will have no effect on the capacitance (50% chose this)
  • Will make the capacitance fluctuate (0% chose this)
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If a DC filament supply is used, it is advisable to periodically reverse the polarity of the filament potential:
  • To lengthen the life of the filament (25% chose this)
  • To lengthen the life of the power source (0% chose this)
  • Both A & B (75% chose this)
  • None of the above (0% chose this)
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The speed of a DC series motor is determined:
  • By the load (50% chose this)
  • By the number of pairs of poles (0% chose this)
  • By the commutator (50% chose this)
  • None of the above (0% chose this)
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Weather information is commonly sent by radio in map form by one-way facsimile transmission. Two common parameters which must be set by the receiving station are:
  • Lines-per-inch (LPI), and primary scan direction (PSD) (100% chose this)
  • Frequency shift (FS), and phase response pattern (PRP) (0% chose this)
  • Black-mode signal (BMS), and frequency jitter tolerance (FJT) (0% chose this)
  • Index of cooperation (IOC), and revolutions per minute (RPM) (0% chose this)
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"A", "B", and "C" batteries are alike, but specifically constructed for a particular function. Explain:
  • "B" battery is for plate and screen power (0% chose this)
  • "C" battery for grid bias voltage (0% chose this)
  • "A" battery for filament power (0% chose this)
  • All of the above (100% chose this)
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Code speed or number of words per minute transmitted have what effect if any on the bandwidth of emission of a radiotelegraph transmitter?
  • It does have an effect. Bandwidth i