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	Polytetrafluoroethylene
B	Polyethylene
C	Polychlorinated biphenyls
D	Polymorphic silicon

2. - E1A03

What is the maximum legal carrier frequency on the 20 meter band for transmitting USB AFSK digital signals having a 1 kHz bandwidth?

Select	Answer
A	14.070 MHz
B	14.100 MHz
C	14.349 MHz
D	14.149 MHz

3. - E1B09

Which amateur stations may be operated under RACES rules?

Select	Answer
A	Any FCC-licensed amateur station except a Technician Class
B	Only those club stations licensed to Amateur Extra Class operators
C	Any FCC-licensed amateur station certified by the responsible civil defense organization for the area served
D	Any FCC-licensed amateur station participating in the Military Auxiliary Radio System (MARS)

4. - E1C03

How do the control operator responsibilities of a station under automatic control differ from one under local control?

Select	Answer
A	Under local control there is no control operator
B	Under automatic control the control operator is not required to be present at the control point
C	Under automatic control there is no control operator
D	Under local control a control operator is not required to be present at a control point

5. - E1D02

Which of the following may transmit special codes intended to obscure the meaning of messages?

Select	Answer
A	Binary control characters
B	Telecommand signals from a space telecommand station
C	Data containing personal information
D	Auxiliary relay links carrying repeater audio

6. - E1E07

What should a VE do if a candidate fails to comply with the examiner's instructions during an amateur operator license examination?

Select	Answer
A	Warn the candidate that continued failure to comply will result in termination of the examination
B	Immediately terminate everyone's examination and close the session
C	Allow the candidate to complete the examination, but invalidate the results
D	Immediately terminate the candidate's examination

7. - E1F03

Under what circumstances may a dealer sell an external RF power amplifier capable of operation below 144 MHz if it has not been granted FCC certification?

Select	Answer
A	The equipment dealer assembled it from a kit
B	It was imported from a manufacturer in another country and was certificated by that country's government
C	It was imported from a manufacturer in a country that does not require certification of RF power amplifiers
D	It was purchased in used condition from an amateur operator and is sold to another amateur operator for use at that operator's station

8. - E2A11

What type of antenna can be used to minimize the effects of spin modulation and Faraday rotation?

Select	Answer
A	A log-periodic dipole array
B	An isotropic antenna
C	A circularly polarized antenna
D	A linearly polarized antenna

9. - E2B01

How many times per second is a new frame transmitted in a fast-scan (NTSC) television system?

Select	Answer
A	120
B	30
C	90
D	60

10. - E2C04

Which of the following frequencies are sometimes used for amateur radio mesh networks?

Select	Answer
A	Frequencies shared with various unlicensed wireless data services
B	The 60 meter band channel centered on 5373 kHz
C	Cable TV channels 41 through 43
D	HF frequencies where digital communications are permitted

11. - E2D03

Which of the following digital modes is especially useful for EME communications?

Select	Answer
A	Olivia
B	JT65
C	PACTOR III
D	MSK144

12. - E2E03

How is the timing of FT4 contacts organized?

Select	Answer
A	Alternating transmissions at 7.5 second intervals
B	Stations take turns on alternate days
C	It depends on the lunar phase
D	By exchanging ACK/NAK packets

13. - E3A14

What is meant by circularly polarized electromagnetic waves?

Select	Answer
A	Waves with a rotating electric field
B	Waves produced by a loop antenna
C	Waves with an electric field bent into a circular shape
D	Waves that circle the Earth

14. - E3B02

What is the approximate maximum range for signals using transequatorial propagation?

Select	Answer
A	7500 miles
B	2500 miles
C	5000 miles
D	1000 miles

15. - E3C06

By how much does the VHF/UHF radio horizon distance exceed the geometric horizon?

Select	Answer
A	By approximately twice the distance
B	By approximately 50 percent of the distance
C	By approximately four times the distance
D	By approximately 15 percent of the distance

16. - E4A07

Which of the following is an advantage of using an antenna analyzer compared to an SWR bridge to measure antenna SWR?

Select	Answer
A	Antenna analyzers automatically tune your antenna for resonance
B	All these choices are correct
C	Antenna analyzers do not need an external RF source
D	Antenna analyzers display a time-varying representation of the modulation envelope

17. - E4B10

Which of the following methods measures intermodulation distortion in an SSB transmitter?

Select	Answer
A	Modulate the transmitter using two AF signals having harmonically related frequencies and observe the RF output with a peak reading wattmeter
B	Modulate the transmitter using two RF signals having non-harmonically related frequencies and observe the RF output with a spectrum analyzer
C	Modulate the transmitter using two RF signals having harmonically related frequencies and observe the RF output with a logic analyzer
D	Modulate the transmitter using two AF signals having non-harmonically related frequencies and observe the RF output with a spectrum analyzer

18. - E4C03

What is the term for the suppression in an FM receiver of one signal by another stronger signal on the same frequency?

Select	Answer
A	Desensitization
B	Cross-modulation interference
C	Frequency discrimination
D	Capture effect

19. - E4D11

Why are odd-order intermodulation products, created within a receiver, of particular interest compared to other products?

Select	Answer
A	Odd-order products of two signals in the band of interest are also likely to be within the band
B	Odd-order intermodulation produces three products for every input signal within the band of interest
C	Odd-order products are an indication of poor image rejection
D	Odd-order products overload the IF filters

20. - E4E04

How can conducted and radiated noise caused by an automobile alternator be suppressed?

Select	Answer
A	By installing a noise suppression resistor and a blocking capacitor in both leads
B	By connecting the radio's power leads directly to the battery and by installing coaxial capacitors in line with the alternator leads
C	By installing filter capacitors in series with the DC power lead and a blocking capacitor in the field lead
D	By installing a high-pass filter in series with the radio's power lead and a low-pass filter in parallel with the field lead

21. - E5A08

What is the phase relationship between the current through and the voltage across a series resonant circuit at resonance?

Select	Answer
A	The voltage and current are in phase
B	The current leads the voltage by 90 degrees
C	The voltage leads the current by 90 degrees
D	The voltage and current are 180 degrees out of phase

22. - E5B10

What is the relationship between the AC current through an inductor and the voltage across an inductor?

Select	Answer
A	Voltage and current are in phase
B	Current leads voltage by 90 degrees
C	Voltage and current are 180 degrees out of phase
D	Voltage leads current by 90 degrees

23. - E5C12

Which point on Figure E5-1 best represents the impedance of a series circuit consisting of a 300-ohm resistor and a 19-picofarad capacitor at 21.200 MHz?

Select	Answer
A	Point 1
B	Point 3
C	Point 7
D	Point 8

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

25. - E6A10

In Figure E6-1, what is the schematic symbol for an N-channel dual-gate MOSFET?

Select	Answer
A	6
B	4
C	5
D	2

26. - E6B09

What is a common use for point-contact diodes?

Select	Answer
A	As an RF detector
B	As a high-voltage rectifier
C	As a constant current source
D	As a constant voltage source

27. - E6C09

What is a Programmable Logic Device (PLD)?

Select	Answer
A	Programmable equipment used for testing digital logic integrated circuits
B	A logic circuit that can be modified during use
C	A programmable collection of logic gates and circuits in a single integrated circuit
D	A type of transistor whose gain can be changed by digital logic circuits

28. - E6D04

Which materials are commonly used as a core in an inductor?

Select	Answer
A	Cobalt and aluminum
B	Ferrite and brass
C	Teflon and Delrin
D	Polystyrene and polyethylene

29. - E6E02

Which of the following device packages is a through-hole type?

Select	Answer
A	Ball grid array
B	SOT
C	PLCC
D	DIP

30. - E6F06

Which of these materials is most commonly used to create photoconductive devices?

Select	Answer
A	An ordinary metal
B	A liquid semiconductor
C	A crystalline semiconductor
D	A heavy metal

31. - E7A09

What logical operation is performed by an exclusive NOR gate?

Select	Answer
A	It produces logic 0 at its output if only one input is logic 1
B	It produces logic 0 at its output only if all inputs are logic 0
C	It produces logic 1 at its output if only one input is logic 1
D	It produces logic 1 at its output only if all inputs are logic 1

32. - E7B09

Which of the following describes how the loading and tuning capacitors are to be adjusted when tuning a vacuum tube RF power amplifier that employs a Pi-network output circuit?

Select	Answer
A	The loading capacitor is adjusted to minimum plate current while alternately adjusting the tuning capacitor for maximum allowable plate current
B	The tuning capacitor is set to maximum capacitance and the loading capacitor is adjusted for minimum plate permissible current
C	The loading capacitor is set to maximum capacitance and the tuning capacitor is adjusted for minimum allowable plate current
D	The tuning capacitor is adjusted for minimum plate current, and the loading capacitor is adjusted for maximum permissible plate current

33. - E7C09

What is a crystal lattice filter?

Select	Answer
A	An audio filter made with four quartz crystals that resonate at 1 kHz intervals
B	A power supply filter made with interlaced quartz crystals
C	A filter with narrow bandwidth and steep skirts made using quartz crystals
D	A filter using lattice-shaped quartz crystals for high-Q performance

34. - E7D03

What device is typically used as a stable voltage reference in a linear voltage regulator?

Select	Answer
A	An SCR
B	A tunnel diode
C	A varactor diode
D	A Zener diode

35. - E7E01

Which of the following can be used to generate FM phone emissions?

Select	Answer
A	A balanced modulator on the audio amplifier
B	A reactance modulator on the final amplifier
C	A reactance modulator on the oscillator
D	A balanced modulator on the oscillator

36. - E7F08

What is the function of decimation?

Select	Answer
A	Reducing the effective sample rate by removing samples
B	Removing unnecessary significant digits
C	Converting data to binary code decimal form
D	Attenuating the signal

37. - E7G06

What is the gain-bandwidth of an operational amplifier?

Select	Answer
A	The frequency at which the open-loop gain of the amplifier equals one
B	The frequency at which the amplifier's offset voltage is zero
C	The maximum frequency for a filter circuit using that type of amplifier
D	The gain of the amplifier at a filter's cutoff frequency

38. - E7H06

Which of the following oscillator circuits are commonly used in VFOs?

Select	Answer
A	Negative feedback and balanced feedback
B	Pierce and Zener
C	Armstrong and deForest
D	Colpitts and Hartley

39. - E8A08

Why would a direct or flash conversion analog-to-digital converter be useful for a software defined radio?

Select	Answer
A	Very high speed allows digitizing high frequencies
B	Very low power consumption decreases frequency drift
C	All these choices are correct
D	Immunity to out-of-sequence coding reduces spurious responses

40. - E8B07

Orthogonal Frequency Division Multiplexing is a technique used for which type of amateur communication?

Select	Answer
A	OFDM signals are not allowed on amateur bands
B	Extremely low-power contacts
C	High-speed digital modes
D	EME

41. - E8C10

How may data rate be increased without increasing bandwidth?

Select	Answer
A	Using a more efficient digital code
B	Increasing analog-to-digital conversion resolution
C	Using forward error correction
D	It is impossible

42. - E8D07

What is a common cause of overmodulation of AFSK signals?

Select	Answer
A	Ground loops
B	Excessive numbers of retries
C	Excessive transmit audio levels
D	Bit errors in the modem

43. - E9A06

What is the effective radiated power relative to a dipole of a repeater station with 200 watts transmitter power output, 4 dB feed line loss, 3.2 dB duplexer loss, 0.8 dB circulator loss, and 10 dBd antenna gain?

Select	Answer
A	126 watts
B	300 watts
C	317 watts
D	2000 watts

44. - E9B09

What type of computer program technique is commonly used for modeling antennas?

Select	Answer
A	Method of Moments
B	Mutual impedance analysis
C	Calculus differentiation with respect to physical properties
D	Graphical analysis

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

46. - E9D10

What happens to feed-point impedance at the base of a fixed length HF mobile antenna when operated below its resonant frequency?

Select	Answer
A	The radiation resistance decreases and the capacitive reactance decreases
B	The radiation resistance decreases and the capacitive reactance increases
C	The radiation resistance increases and the capacitive reactance decreases
D	The radiation resistance increases and the capacitive reactance increases

47. - E9E05

How must an antenna's driven element be tuned to use a hairpin matching system?

Select	Answer
A	The driven element radiation resistance must be higher than the characteristic impedance of the transmission line
B	The driven element resonance must be lower than the operating frequency
C	The driven element reactance must be capacitive
D	The driven element reactance must be inductive

48. - E9F01

What is the velocity factor of a transmission line?

Select	Answer
A	The ratio of the characteristic impedance of the line to the terminating impedance
B	The velocity of the wave in the transmission line divided by the velocity of light in a vacuum
C	The index of shielding for coaxial cable
D	The velocity of the wave in the transmission line multiplied by the velocity of light in a vacuum

49. - E9G10

What do the arcs on a Smith chart represent?

Select	Answer
A	Points with constant resistance
B	Frequency
C	SWR
D	Points with constant reactance

50. - E9H04

What is an advantage of placing a grounded electrostatic shield around a small loop direction-finding antenna?

Select	Answer
A	It eliminates tracking errors caused by strong out-of-band signals
B	It adds capacitive loading, increasing the bandwidth of the antenna
C	It eliminates unbalanced capacitive coupling to the surroundings, improving the nulls
D	It increases signal strength by providing a better match to the feed line

Figure E5-1

Figure E6-1