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

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1. - E0A04

When evaluating a site with multiple transmitters operating at the same time, the operators and licensees of which transmitters are responsible for mitigating over-exposure situations?

Select	Answer
A	Only the most powerful transmitter
B	Each transmitter that produces 5 percent or more of its MPE limit in areas where the total MPE limit is exceeded.
C	Only commercial transmitters
D	Each transmitter operating with a duty cycle greater than 50 percent

2. - E1A13

Who must be in physical control of the station apparatus of an amateur station aboard any vessel or craft that is documented or registered in the United States?

Select	Answer
A	Only a person named in an amateur station license grant
B	Only a person with an FCC Marine Radio license grant
C	Any person holding an FCC issued amateur license or who is authorized for alien reciprocal operation
D	Any person named in an amateur station license grant or a person holding an unrestricted Radiotelephone Operator Permit

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

4. - E1C08

What is the maximum permissible duration of a remotely controlled station's transmissions if its control link malfunctions?

Select	Answer
A	30 seconds
B	10 minutes
C	3 minutes
D	5 minutes

5. - E1D12

Which of the following amateur stations may transmit one-way communications?

Select	Answer
A	All these choices are correct
B	A space station, beacon station, or telecommand station
C	A message forwarding station or automatically controlled digital station
D	A local repeater or linked repeater station

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

7. - E1F06

Under what circumstances might the FCC issue a Special Temporary Authority (STA) to an amateur station?

Select	Answer
A	To provide temporary operation while awaiting normal licensing
B	To allow regular operation on Land Mobile channels
C	To provide for experimental amateur communications
D	To provide additional spectrum for personal use

8. - E2A01

What is the direction of an ascending pass for an amateur satellite?

Select	Answer
A	From south to north
B	From north to south
C	From east to west
D	From west to east

9. - E2B03

How is an interlaced scanning pattern generated in a fast-scan (NTSC) television system?

Select	Answer
A	By scanning odd numbered lines in one field and even numbered lines in the next
B	By scanning each field from bottom to top
C	By scanning lines from left to right in one field and right to left in the next
D	By scanning two fields simultaneously

10. - E2C12

What technique do individual nodes use to form a mesh network?

Select	Answer
A	Discovery and link establishment protocols
B	Acting as store-and-forward digipeaters
C	Forward error correction and Viterbi codes
D	Custom code plugs for the local trunking systems

11. - E2D06

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

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

12. - E2E09

Which of the following HF digital modes uses variable-length coding for bandwidth efficiency?

Select	Answer
A	PACTOR
B	MT63
C	RTTY
D	PSK31

13. - E3A13

Which of these emission modes is best for auroral propagation?

Select	Answer
A	CW
B	FM
C	SSB
D	RTTY

14. - E3B09

At what time of year is sporadic E propagation most likely to occur?

Select	Answer
A	Around the equinoxes, especially the fall equinox
B	Around the solstices, especially the winter solstice
C	Around the equinoxes, especially the spring equinox
D	Around the solstices, especially the summer solstice

15. - E3C07

Which of the following descriptors indicates the greatest solar flare intensity?

Select	Answer
A	Class M
B	Class B
C	Class X
D	Class A

16. - E4A05

What is the purpose of the prescaler function on a frequency counter?

Select	Answer
A	It amplifies low-level signals for more accurate counting
B	It prevents oscillation in a low-frequency counter circuit
C	It multiplies a higher frequency signal so a low-frequency counter can display the operating frequency
D	It divides a higher frequency signal so a low-frequency counter can display the input frequency

17. - E4B05

What three test loads are used to calibrate an RF vector network analyzer?

Select	Answer
A	Short circuit, open circuit, and resonant circuit
B	50 ohms, 75 ohms, and 90 ohms
C	Short circuit, open circuit, and 50 ohms
D	50 ohms through 1/8 wavelength, 1/4 wavelength, and 1/2 wavelength of coaxial cable

18. - E4C08

An SDR receiver is overloaded when input signals exceed what level?

Select	Answer
A	The reference voltage of the analog-to-digital converter
B	The maximum count value of the analog-to-digital converter
C	One-half the maximum sample rate
D	One-half the maximum sampling buffer size

19. - E4D08

What causes intermodulation in an electronic circuit?

Select	Answer
A	Lack of neutralization
B	Positive feedback
C	Too little gain
D	Nonlinear circuits or devices

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 installing filter capacitors in series with the DC power lead and a blocking capacitor in the field lead
C	By connecting the radio's power leads directly to the battery and by installing coaxial capacitors in line with the alternator leads
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. - E5A16

What is the resonant frequency of an RLC circuit if R is 33 ohms, L is 50 microhenries and C is 10 picofarads?

Select	Answer
A	23.5 kHz
B	7.12 MHz
C	7.12 kHz
D	23.5 MHz

22. - E5B03

How is impedance in polar form converted to an equivalent admittance?

Select	Answer
A	Take the reciprocal of the angle and change the sign of the magnitude
B	Take the square root of the magnitude and add 180 degrees to the angle
C	Take the reciprocal of the magnitude and change the sign of the angle
D	Square the magnitude and subtract 90 degrees from the angle

23. - E5C05

What is the name of the diagram used to show the phase relationship between impedances at a given frequency?

Select	Answer
A	Venn diagram
B	Near field diagram
C	Phasor diagram
D	Far field diagram

24. - E5D06

In what direction is the magnetic field oriented about a conductor in relation to the direction of electron flow?

Select	Answer
A	In the same direction as the current
B	In a direction opposite to the current
C	In a circle around the conductor
D	In all directions; omni-directional

25. - E6A04

What is the name given to an impurity atom that adds holes to a semiconductor crystal structure?

Select	Answer
A	Acceptor impurity
B	Insulator impurity
C	N-type impurity
D	Donor impurity

26. - E6B09

What is a common use for point-contact diodes?

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

27. - E6C08

In Figure E6-3, what is the schematic symbol for a NAND gate?

Select	Answer
A	1
B	4
C	2
D	3

28. - E6D10

What is a primary advantage of using a toroidal core instead of a solenoidal core in an inductor?

Select	Answer
A	Toroidal cores have lower Q characteristics
B	Toroidal cores exhibit greater hysteresis
C	Toroidal cores confine most of the magnetic field within the core material
D	Toroidal cores make it easier to couple the magnetic energy into other components

29. - E6E12

Why are DIP through-hole package ICs not typically used at UHF and higher frequencies?

Select	Answer
A	Epoxy coating is conductive above 300 MHz
B	Too many pins
C	Unsuitable for combining analog and digital signals
D	Excessive lead length

30. - E6F01

What absorbs the energy from light falling on a photovoltaic cell?

Select	Answer
A	Protons
B	Photons
C	Electrons
D	Holes

31. - E7A08

What logical operation does an OR gate perform?

Select	Answer
A	It produces logic 1 at its output if all inputs are logic 0
B	It only produces logic 0 at its output when all inputs are logic 1
C	It produces logic 1 at its output if any or all inputs are logic 1
D	It produces logic 0 at its output if all inputs are logic 1

32. - E7B07

Which of the following is a likely result when a Class C amplifier is used to amplify a single-sideband phone signal?

Select	Answer
A	Signal inversion
B	Reduced intermodulation products
C	Signal distortion and excessive bandwidth
D	Increased overall intelligibility

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

34. - E7D09

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

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

35. - E7E03

What is a frequency discriminator stage in a FM receiver?

Select	Answer
A	A circuit for detecting FM signals
B	An FM generator circuit
C	A circuit for filtering two closely adjacent signals
D	An automatic band-switching circuit

36. - E7F05

How frequently must an analog signal be sampled by an analog-to-digital converter so that the signal can be accurately reproduced?

Select	Answer
A	At least twice the rate of the highest frequency component of the signal
B	At the same rate as the highest frequency component of the signal
C	At least half the rate of the highest frequency component of the signal
D	At four times the rate of the highest frequency component of the signal

37. - E7G04

What is meant by the "op-amp input offset voltage"?

Select	Answer
A	The output voltage of the op-amp minus its input voltage
B	The difference between the output voltage of the op-amp and the input voltage required in the immediately following stage
C	The potential between the amplifier input terminals of the op-amp in an open loop condition
D	The differential input voltage needed to bring the open loop output voltage to zero

38. - E7H10

What information is contained in the lookup table of a direct digital synthesizer (DDS)?

Select	Answer
A	The phase relationship between a voltage-controlled oscillator and the output waveform
B	Frequently used receiver and transmitter frequencies
C	The phase relationship between a reference oscillator and the output waveform
D	Amplitude values that represent the desired waveform

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	All these choices are correct
C	Immunity to out-of-sequence coding reduces spurious responses
D	Very low power consumption decreases frequency drift

40. - E8B04

What is the modulation index of an FM-phone signal having a maximum carrier deviation of plus or minus 6 kHz when modulated with a 2 kHz modulating frequency?

Select	Answer
A	6000
B	3
C	2000
D	1/3

41. - E8C03

Why should phase-shifting of a PSK signal be done at the zero crossing of the RF signal?

Select	Answer
A	To simplify modulation
B	To improve carrier suppression
C	All these choices are correct
D	To minimize bandwidth

42. - E8D08

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

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

43. - E9A11

Which of the following factors determines ground losses for a ground-mounted vertical antenna operating in the 3 MHz to 30 MHz range?

Select	Answer
A	Take-off angle
B	Distance from the transmitter
C	The standing wave ratio
D	Soil conductivity

44. - E9B06

What is the elevation angle of peak response in the antenna radiation pattern shown in Figure E9-2?

Select	Answer
A	75 degrees
B	25 degrees
C	7.5 degrees
D	45 degrees

45. - E9C10

Which of the following describes a Zepp antenna?

Select	Answer
A	An end-fed dipole antenna
B	An omni-directional antenna commonly used for satellite communications
C	A vertical array capable of quickly changing the direction of maximum radiation by changing phasing lines
D	A dipole constructed from zip cord

46. - E9D09

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

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

47. - E9E03

What is the name of the matching system that uses a section of transmission line connected in parallel with the feed line at or near the feed point?

Select	Answer
A	The stub match
B	The gamma match
C	The omega match
D	The delta match

48. - E9F04

What impedance does a 1/2-wavelength transmission line present to a generator when the line is shorted at the far end?

Select	Answer
A	The same as the characteristic impedance of the line
B	The same as the output impedance of the generator
C	Very high impedance
D	Very low impedance

49. - E9G04

What are the two families of circles and arcs that make up a Smith chart?

Select	Answer
A	Resistance and voltage
B	Voltage and impedance
C	Reactance and voltage
D	Resistance and reactance

50. - E9H11

What feature of a cardioid pattern antenna makes it useful for direction finding?

Select	Answer
A	High radiation angle
B	A very sharp peak
C	A very sharp single null
D	Broadband response

Figure E6-3

Figure E9-2