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2024 Amateur Extra pool
35 / 602 questions need explanations
94.2% complete
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How does Q65 differ from JT65?
  • Keyboard-to keyboard operation is supported (0% chose this)
  • Quadrature modulation is used (0% chose this)
  • Multiple receive cycles are averaged (0% chose this)
  • All these choices are correct (0% chose this)
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Which of these digital modes has the highest data throughput under clear communication conditions?
  • MFSK16 (0% chose this)
  • 170 Hz shift, 45 baud RTTY (0% chose this)
  • FT8 (0% chose this)
  • PACTOR IV (0% chose this)
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Where is transequatorial propagation (TEP) most likely to occur?
  • Between points separated by 2,000 miles to 3,000 miles over a path perpendicular to the geomagnetic equator (0% chose this)
  • Between points located 1,500 miles to 2,000 miles apart on the geomagnetic equator (0% chose this)
  • Between points located at each other’s antipode (0% chose this)
  • Through the region where the terminator crosses the geographic equator (0% chose this)
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What is the cause of short-term radio blackouts?
  • Coronal mass ejections (0% chose this)
  • Sunspots on the solar equator (0% chose this)
  • North-oriented interplanetary magnetic field (0% chose this)
  • Solar flares (0% chose this)
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Which of the following signal paths is most likely to experience high levels of absorption when the A-index or K-index is elevated?
  • Transequatorial (0% chose this)
  • Through the auroral oval (0% chose this)
  • Sporadic-E (0% chose this)
  • NVIS (0% chose this)
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Which trigger mode is most effective when using an oscilloscope to measure a linear power supply’s output ripple?
  • Single-shot (0% chose this)
  • Edge (0% chose this)
  • Level (0% chose this)
  • Line (0% chose this)
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Which of the following can be measured by a two-port vector network analyzer?
  • Phase noise (0% chose this)
  • Filter frequency response (0% chose this)
  • Pulse rise time (0% chose this)
  • Forward power (0% chose this)
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What is the purpose of the receiver IF Shift control?
  • To permit listening on a different frequency from the transmitting frequency (0% chose this)
  • To change frequency rapidly (0% chose this)
  • To reduce interference from stations transmitting on adjacent frequencies (0% chose this)
  • To tune in stations slightly off frequency without changing the transmit frequency (0% chose this)
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How can conducted noise from an automobile battery charging system be suppressed?
  • By installing filter capacitors in series with the alternator leads (0% chose this)
  • By installing a noise suppression resistor and a blocking capacitor at the battery (0% chose this)
  • By installing a high-pass filter in series with the radio’s power lead and a low-pass filter in parallel with the antenna feed line (0% chose this)
  • By installing ferrite chokes on the charging system leads (0% chose this)
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What is the purpose of a single point ground panel?
  • Remove AC power in case of a short-circuit (0% chose this)
  • Prevent common-mode transients in multi-wire systems (0% chose this)
  • Eliminate air gaps between protected and non-protected circuits (0% chose this)
  • Ensure all lightning protectors activate at the same time (0% chose this)
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What is the phase relationship between current and voltage for reactive power?
  • They are out of phase (0% chose this)
  • They are in phase (0% chose this)
  • They are 90 degrees out of phase (0% chose this)
  • They are 45 degrees out of phase (0% chose this)
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What combines to create the self-resonance of a component?
  • The component’s resistance and reactance (0% chose this)
  • The component’s nominal and parasitic reactance (0% chose this)
  • The component’s inductance and capacitance (0% chose this)
  • The component’s electrical length and impedance (0% chose this)
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What is the primary cause of loss in film capacitors at RF?
  • Inductance (0% chose this)
  • Dielectric loss (0% chose this)
  • Self-discharge (0% chose this)
  • Skin effect (0% chose this)
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What property of an LED's semiconductor material determines its forward voltage drop?
  • Intrinsic resistance (0% chose this)
  • Band gap (0% chose this)
  • Junction capacitance (0% chose this)
  • Junction depth (0% chose this)
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Which of the following is a common use of a Schottky diode?
  • In oscillator circuits as the negative resistance element (0% chose this)
  • As a variable capacitance in an automatic frequency control circuit (0% chose this)
  • In power supplies as a constant voltage reference (0% chose this)
  • As a VHF/UHF mixer or detector (0% chose this)
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Which of the following digital logic families has the lowest power consumption?
  • Schottky TTL (0% chose this)
  • ECL (0% chose this)
  • NMOS (0% chose this)
  • CMOS (0% chose this)
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Why are cores of inductors and transformers sometimes constructed of thin layers?
  • To simplify assembly during manufacturing (0% chose this)
  • To reduce power loss from eddy currents in the core (0% chose this)
  • To increase the cutoff frequency by reducing capacitance (0% chose this)
  • To save cost by reducing the amount of magnetic material (0% chose this)
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Which of the following materials has the highest temperature stability of its magnetic characteristics?
  • Brass (0% chose this)
  • Powdered iron (0% chose this)
  • Ferrite (0% chose this)
  • Aluminum (0% chose this)
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What circuit is required at the output of an RF switching amplifier?
  • A filter to remove harmonic content (0% chose this)
  • A high-pass filter to compensate for low gain at low frequencies (0% chose this)
  • A matched load resistor to prevent damage by switching transients (0% chose this)
  • A temperature compensating load resistor to improve linearity (0% chose this)
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What is characteristic of an emitter follower (or common collector) amplifier?
  • Low input impedance and phase inversion from input to output (0% chose this)
  • Differential inputs and single output (0% chose this)
  • Acts as an OR circuit if one input is grounded (0% chose this)
  • Input and output signals in-phase (0% chose this)
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Which of the following is most frequently used as a band-pass or notch filter in VHF and UHF transceivers?
  • A Sallen-Key filter (0% chose this)
  • A helical filter (0% chose this)
  • A swinging choke filter (0% chose this)
  • A finite impulse response filter (0% chose this)
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What is Quadrature Amplitude Modulation or QAM?
  • A technique for digital data compression used in digital television which removes redundancy in the data by comparing bit amplitudes (0% chose this)
  • Transmission of data by modulating the amplitude of two carriers of the same frequency but 90 degrees out of phase (0% chose this)
  • A method of performing single sideband modulation by shifting the phase of the carrier and modulation components of the signal (0% chose this)
  • A technique for analog modulation of television video signals using phase modulation and compression (0% chose this)
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What does the term “ground gain” mean?
  • The change in signal strength caused by grounding the antenna (0% chose this)
  • The gain of the antenna with respect to a dipole at ground level (0% chose this)
  • To force net gain to 0 dB by grounding part of the antenna (0% chose this)
  • An increase in signal strength from ground reflections in the environment of the antenna (0% chose this)
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Which frequency band has the smallest first Fresnel zone?
  • 5.8 GHz (0% chose this)
  • 3.4 GHz (0% chose this)
  • 2.4 GHz (0% chose this)
  • 900 MHz (0% chose this)
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What is the purpose of feeding an off-center-fed dipole (OCFD) between the center and one end instead of at the midpoint?
  • To create a similar feed point impedance on multiple bands (0% chose this)
  • To suppress off-center lobes at higher frequencies (0% chose this)
  • To resonate the antenna across a wider range of frequencies (0% chose this)
  • To reduce common-mode current coupling on the feed line shield (0% chose this)
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Approximately how long is a Yagi’s driven element?
  • 234 divided by frequency in MHz (0% chose this)
  • 1005 divided by frequency in MHz (0% chose this)
  • 1/4 wavelength (0% chose this)
  • 1/2 wavelength (0% chose this)
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Why do most two-element Yagis with normal spacing have a reflector instead of a director?
  • Lower SWR (0% chose this)
  • Higher receiving directivity factor (0% chose this)
  • Greater front-to-side (0% chose this)
  • Higher gain (0% chose this)
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What is the purpose of making a Yagi’s parasitic elements either longer or shorter than resonance?
  • Wind torque cancellation (0% chose this)
  • Mechanical balance (0% chose this)
  • Control of phase shift (0% chose this)
  • Minimize losses (0% chose this)
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What Yagi driven element feed point impedance is required to use a beta or hairpin matching system?
  • Capacitive (driven element electrically shorter than 1/2 wavelength) (0% chose this)
  • Inductive (driven element electrically longer than 1/2 wavelength) (0% chose this)
  • Purely resistive (0% chose this)
  • Purely reactive (0% chose this)
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What is the purpose of using multiple driven elements connected through phasing lines?
  • To control the antenna’s radiation pattern (0% chose this)
  • To prevent harmonic radiation from the transmitter (0% chose this)
  • To allow single-band antennas to operate on other bands (0% chose this)
  • To create a low-angle radiation pattern (0% chose this)
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What indicates the correct value of terminating resistance for a Beverage antenna?
  • Maximum feed point DC resistance at the center of the desired frequency range (0% chose this)
  • Minimum low-angle front-to-back ratio at the design frequency (0% chose this)
  • Maximum DC current in the terminating resistor (0% chose this)
  • Minimum variation in SWR over the desired frequency range (0% chose this)
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What is the function of a Beverage antenna’s termination resistor?
  • Increase the front-to-side ratio (0% chose this)
  • Absorb signals from the reverse direction (0% chose this)
  • Decrease SWR bandwidth (0% chose this)
  • Eliminate harmonic reception (0% chose this)
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What type of radiation pattern is created by a single-turn, terminated loop such as a pennant antenna?
  • Cardioid (0% chose this)
  • Bidirectional (0% chose this)
  • Omnidirectional (0% chose this)
  • Hyperbolic (0% chose this)
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What is meant by “100% tie-off” regarding tower safety?
  • All loose ropes and guys secured to a fixed structure (0% chose this)
  • At least one lanyard attached to the tower at all times (0% chose this)
  • All tools secured to the climber’s harness (0% chose this)
  • All circuit breakers feeding power to the tower must be tied closed with tape, cable, or ties (0% chose this)
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Which of the following types of equipment are exempt from RF exposure evaluations?
  • Transceivers with less than 7 watts of RF output (0% chose this)
  • Antennas that radiate only in the near field (0% chose this)
  • Hand-held transceivers sold before May 3, 2021 (0% chose this)
  • Dish antennas less than one meter in diameter (0% chose this)
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