US Amateur Radio - Amateur Extra (Element 4, 2020-2024) Practice Test

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1. - E0A10

What toxic material may be present in some electronic components such as high voltage capacitors and transformers?

Select	Answer
A	Polychlorinated biphenyls
B	Polytetrafluoroethylene
C	Polyethylene
D	Polymorphic silicon

2. - E1A12

What special operating frequency restrictions are imposed on slow scan TV transmissions?

Select	Answer
A	They are restricted to phone band segments
B	They are restricted to 7.245 MHz, 14.245 MHz, 21.345 MHz, and 28.945 MHz
C	They are not permitted above 54 MHz
D	None; they are allowed on all amateur frequencies

3. - E1B08

What limitations may the FCC place on an amateur station if its signal causes interference to domestic broadcast reception, assuming that the receivers involved are of good engineering design?

Select	Answer
A	The amateur station must cease operation on all frequencies above 30 MHz
B	The amateur station must cease operation
C	The amateur station must cease operation on all frequencies below 30 MHz
D	The amateur station must avoid transmitting during certain hours on frequencies that cause the interference

4. - E1C09

What is the highest modulation index permitted at the highest modulation frequency for angle modulation below 29.0 MHz?

Select	Answer
A	0.5
B	1.0
C	3.0
D	2.0

5. - E1D11

Which amateur stations are eligible to operate as Earth stations?

Select	Answer
A	Any amateur station whose licensee has filed a pre-space notification with the FCC's International Bureau
B	Only those of General, Advanced or Amateur Extra Class operators
C	Only those of Amateur Extra Class operators
D	Any amateur station, subject to the privileges of the class of operator license held by the control operator

6. - E1E04

Which of the following best describes the Volunteer Examiner accreditation process?

Select	Answer
A	The prospective VE obtains accreditation from the FCC
B	The amateur operator applying must pass a VE examination administered by the FCC Enforcement Bureau
C	Each General, Advanced and Amateur Extra Class operator is automatically accredited as a VE when the license is granted
D	The procedure by which a VEC confirms that the VE applicant meets FCC requirements to serve as an examiner

7. - E1F07

When may an amateur station send a message to a business?

Select	Answer
A	When the total money involved does not exceed $25
B	When neither the amateur nor his or her employer has a pecuniary interest in the communications
C	When the control operator is employed by the FCC or another government agency
D	When transmitting international third-party communications

8. - E2A08

Why should effective radiated power to a satellite that uses a linear transponder be limited?

Select	Answer
A	To prevent creating errors in the satellite telemetry
B	To prevent the satellite from emitting out-of-band signals
C	To avoid reducing the downlink power to all other users
D	To avoid interfering with terrestrial QSOs

9. - E2B04

How is color information sent in analog SSTV?

Select	Answer
A	Color information is sent on a 2.8 kHz subcarrier
B	Color lines are sent sequentially
C	Color is sent in a color burst at the end of each line
D	Color is amplitude modulated on the frequency modulated intensity signal

10. - E2C06

During a VHF/UHF contest, in which band segment would you expect to find the highest level of SSB or CW activity?

Select	Answer
A	In the middle of the band, usually 25 kHz above the national calling frequency
B	In the middle of each band, usually on the national calling frequency
C	At the top of each band, usually in a segment reserved for contests
D	In the weak signal segment of the band, with most of the activity near the calling frequency

11. - E2D06

Which of the following describes a method of establishing EME contacts?

Select	Answer
A	Judging optimum transmission times by monitoring beacons reflected from the moon
B	High-speed CW identification to avoid fading
C	Storing and forwarding digital messages
D	Time synchronous transmissions alternately from each station

12. - E2E05

Which of these digital modes does not support keyboard-to-keyboard operation?

Select	Answer
A	RTTY
B	PSK31
C	MFSK
D	PACTOR

13. - E3A13

Which of these emission modes is best for auroral propagation?

Select	Answer
A	CW
B	FM
C	SSB
D	RTTY

14. - E3B05

Which amateur bands typically support long-path propagation?

Select	Answer
A	Only 160 meters to 40 meters
B	Only 30 meters to 10 meters
C	6 meters to 2 meters
D	160 meters to 10 meters

15. - E3C01

What does the radio communication term "ray tracing" describe?

Select	Answer
A	Modeling a radio wave's path through the ionosphere
B	Evaluating high voltage sources for x-rays
C	Determining the radiation pattern from an array of antennas
D	The process in which an electronic display presents a pattern

16. - E4A06

What is the effect of aliasing on a digital oscilloscope caused by setting the time base too slow?

Select	Answer
A	All signals will have a DC offset
B	Calibration of the vertical scale is no longer valid
C	A false, jittery low-frequency version of the signal is displayed
D	Excessive blanking occurs, which prevents display of the signal

17. - E4B09

What is indicated if the current reading on an RF ammeter placed in series with the antenna feed line of a transmitter increases as the transmitter is tuned to resonance?

Select	Answer
A	There is more power going into the antenna
B	There is an impedance mismatch between the antenna and feed line
C	The transmitter is not properly neutralized
D	There is possibly a short to ground in the feed line

18. - E4C13

How does a narrow-band roofing filter affect receiver performance?

Select	Answer
A	It improves sensitivity by reducing front end noise
B	It improves intelligibility by using low Q circuitry to reduce ringing
C	All these choices are correct
D	It improves dynamic range by attenuating strong signals near the receive frequency

19. - E4D02

Which of the following describes problems caused by poor dynamic range in a receiver?

Select	Answer
A	Oscillator instability and severe audio distortion of all but the strongest received signals
B	Spurious signals caused by cross-modulation and desensitization from strong adjacent signals
C	Cross-modulation of the desired signal and insufficient audio power to operate the speaker
D	Oscillator instability requiring frequent retuning and loss of ability to recover the opposite sideband

20. - E4E10

What might be the cause of a loud roaring or buzzing AC line interference that comes and goes at intervals?

Select	Answer
A	Arcing contacts in a thermostatically controlled device
B	A defective doorbell or doorbell transformer inside a nearby residence
C	All these choices are correct
D	A malfunctioning illuminated advertising display

21. - E5A15

Which of the following increases Q for inductors and capacitors?

Select	Answer
A	Lower reactance
B	Higher self-resonant frequency
C	Lower self-resonant frequency
D	Lower losses

22. - E5B01

What is the term for the time required for the capacitor in an RC circuit to be charged to 63.2% of the applied voltage or to discharge to 36.8% of its initial voltage?

Select	Answer
A	A time factor of one
B	An exponential rate of one
C	One exponential period
D	One time constant

23. - E5C02

How are impedances described in polar coordinates?

Select	Answer
A	By X and R values
B	By Y and G values
C	By phase angle and magnitude
D	By real and imaginary parts

24. - E5D10

How can the true power be determined in an AC circuit where the voltage and current are out of phase?

Select	Answer
A	By dividing the reactive power by the power factor
B	By multiplying the reactive power by the power factor
C	By multiplying the apparent power by the power factor
D	By dividing the apparent power by the power factor

25. - E6A01

In what application is gallium arsenide used as a semiconductor material?

Select	Answer
A	In high-power audio circuits
B	In microwave circuits
C	In very low-frequency RF circuits
D	In high-current rectifier circuits

26. - E6B11

What is used to control the attenuation of RF signals by a PIN diode?

Select	Answer
A	Reverse voltage larger than the RF signal
B	Capacitance of an RF coupling capacitor
C	A sub-harmonic pump signal
D	Forward DC bias current

27. - E6C01

What is the function of hysteresis in a comparator?

Select	Answer
A	To prevent input noise from causing unstable output signals
B	To allow the comparator to be used with AC input signals
C	To increase the sensitivity
D	To cause the output to change states continually

28. - E6D01

Why should core saturation of an impedance matching transformer be avoided?

Select	Answer
A	Harmonics and distortion could result
B	RF susceptance would increase
C	Magnetic flux would increase with frequency
D	Temporary changes of the core permeability could result

29. - E6E11

What is a characteristic of DIP packaging used for integrated circuits?

Select	Answer
A	Package mounts in a direct inverted position
B	Low leakage doubly insulated package
C	Two chips in each package (Dual In Package)
D	A total of two rows of connecting pins placed on opposite sides of the package (Dual In-line Package)

30. - E6F07

What is a solid-state relay?

Select	Answer
A	A device that uses semiconductors to implement the functions of an electromechanical relay
B	A semiconductor passive delay line
C	A mechanical relay that latches in the on or off state each time it is pulsed
D	A relay using transistors to drive the relay coil

31. - E7A01

Which circuit is bistable?

Select	Answer
A	A flip-flop
B	An AND gate
C	A bipolar amplifier
D	An OR gate

32. - E7B08

How can an RF power amplifier be neutralized?

Select	Answer
A	By reducing the driving power
B	By feeding a 180-degree out-of-phase portion of the output back to the input
C	By increasing the driving power
D	By feeding an in-phase component of the output back to the input

33. - E7C07

Which describes a Pi-L-network used for matching a vacuum tube final amplifier to a 50-ohm unbalanced output?

Select	Answer
A	A matching network in which all components are isolated from ground
B	A Pi-network with an additional series inductor on the output
C	A Phase Inverter Load network
D	A network with only three discrete parts

34. - E7D09

What is the main reason to use a charge controller with a solar power system?

Select	Answer
A	Prevention of battery damage due to overcharge
B	Control of electrolyte levels during battery discharge
C	Matching of day and night charge rates
D	Prevention of battery undercharge

35. - E7E08

What are the principal frequencies that appear at the output of a mixer circuit?

Select	Answer
A	1.414 and 0.707 times the input frequency
B	Two and four times the original frequency
C	The two input frequencies along with their sum and difference frequencies
D	The square root of the product of input frequencies

36. - E7F09

Why is an anti-aliasing digital filter required in a digital decimator?

Select	Answer
A	It notches out the sampling frequency to avoid sampling errors
B	It removes high-frequency signal components that would otherwise be reproduced as lower frequency components
C	It peaks the response of the decimator, improving bandwidth
D	It removes low-frequency signal components to eliminate the need for DC restoration

37. - E7G02

What is ringing in a filter?

Select	Answer
A	An echo caused by a long time delay
B	A reduction in high frequency response
C	Partial cancellation of the signal over a range of frequencies
D	Undesired oscillations added to the desired signal

38. - E7H14

What is a phase-locked loop circuit?

Select	Answer
A	An electronic servo loop consisting of a ratio detector, reactance modulator, and voltage-controlled oscillator
B	An electronic circuit also known as a monostable multivibrator
C	An electronic servo loop consisting of a phase detector, a low-pass filter, a voltage-controlled oscillator, and a stable reference oscillator
D	An electronic circuit consisting of a precision push-pull amplifier with a differential input

39. - E8A02

Which of the following is a type of analog-to-digital conversion?

Select	Answer
A	Level shifting
B	Harmonic regeneration
C	Phase reversal
D	Successive approximation

40. - E8B06

What is the deviation ratio of an FM-phone signal having a maximum frequency swing of plus or minus 7.5 kHz when the maximum modulation frequency is 3.5 kHz?

Select	Answer
A	47
B	0.214
C	0.47
D	2.14

41. - E8C06

What is the bandwidth of a 170-hertz shift, 300-baud ASCII transmission?

Select	Answer
A	1.0 kHz
B	0.3 kHz
C	0.5 kHz
D	0.1 Hz

42. - E8D08

What parameter evaluates distortion of an AFSK signal caused by excessive input audio levels?

Select	Answer
A	Baud rate
B	Intermodulation Distortion (IMD)
C	Repeat Request Rate (RRR)
D	Signal-to-noise ratio

43. - E9A04

Which of the following factors affect the feed point impedance of an antenna?

Select	Answer
A	The input power level
B	Antenna height
C	Transmission line length
D	The settings of an antenna tuner at the transmitter

44. - E9B11

What is a disadvantage of decreasing the number of wire segments in an antenna model below 10 segments per half-wavelength?

Select	Answer
A	The computed feed point impedance may be incorrect
B	The resulting design will favor radiation of harmonic energy
C	Ground conductivity will not be accurately modeled
D	The antenna will become mechanically unstable

45. - E9C14

How does the performance of a horizontally polarized antenna mounted on the side of a hill compare with the same antenna mounted on flat ground?

Select	Answer
A	The horizontal beamwidth decreases in the downhill direction
B	The main lobe takeoff angle increases in the downhill direction
C	The main lobe takeoff angle decreases in the downhill direction
D	The horizontal beamwidth increases in the uphill direction

46. - E9D09

What is the function of a loading coil used as part of an HF mobile antenna?

Select	Answer
A	To increase the SWR bandwidth
B	To lower the Q
C	To lower the losses
D	To cancel capacitive reactance

47. - E9E06

Which of these feed line impedances would be suitable for constructing a quarter-wave Q-section for matching a 100-ohm loop to 50-ohm feed line?

Select	Answer
A	75 ohms
B	450 ohms
C	62 ohms
D	50 ohms

48. - E9F10

What impedance does a 1/8-wavelength transmission line present to a generator when the line is shorted at the far end?

Select	Answer
A	A capacitive reactance
B	Zero
C	An inductive reactance
D	The same as the characteristic impedance of the line

49. - E9G07

On the Smith chart shown in Figure E9-3, what is the only straight line shown?

Select	Answer
A	The voltage axis
B	The resistance axis
C	The reactance axis
D	The current axis

50. - E9H08

What is the function of a sense antenna?

Select	Answer
A	It allows DF antennas to receive signals at different vertical angles
B	It modifies the pattern of a DF antenna array to provide a null in one direction
C	It increases the sensitivity of a DF antenna array
D	It provides diversity reception that cancels multipath signals

Figure E9-3