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

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1. - E0A08

What does SAR measure?

Select	Answer
A	Synthetic Aperture Ratio of the human body
B	The rate of RF energy reflected from stationary terrain
C	Signal Amplification Rating
D	The rate at which RF energy is absorbed by the body

2. - E1A08

If a station in a message forwarding system inadvertently forwards a message that is in violation of FCC rules, who is primarily accountable for the rules violation?

Select	Answer
A	The control operator of the originating station
B	The control operator of the packet bulletin board station
C	The control operators of all the stations in the system
D	The control operators of all the stations in the system not authenticating the source from which they accept communications

3. - E1B09

Which amateur stations may be operated under RACES rules?

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

4. - E1C02

Which of the following types of communications may be transmitted to amateur stations in foreign countries?

Select	Answer
A	Messages intended for users of the maritime satellite service
B	All these choices are correct
C	Communications incidental to the purpose of the amateur service and remarks of a personal nature
D	Business-related messages for non-profit organizations

5. - E1D06

What is the maximum permitted transmitter output power when operating a model craft by telecommand?

Select	Answer
A	100 watts
B	2 watts
C	1 watt
D	5 watts

6. - E1E12

What must the VE team do with the application form if the examinee does not pass the exam?

Select	Answer
A	Destroy the application form
B	Send the application form to the FCC and inform the FCC of the grade
C	Return the application document to the examinee
D	Maintain the application form with the VEC's records

7. - E1F08

Which of the following types of amateur station communications are prohibited?

Select	Answer
A	Communications that have political content, except as allowed by the Fairness Doctrine
B	Communications transmitted for hire or material compensation, except as otherwise provided in the rules
C	Communications that have religious content
D	Communications in a language other than English

8. - E2A12

What is the purpose of digital store-and-forward functions on an amateur radio satellite?

Select	Answer
A	To delay download of telemetry between satellites
B	To upload operational software for the transponder
C	To relay messages between satellites
D	To store digital messages in the satellite for later download by other stations

9. - E2B06

What is vestigial sideband modulation?

Select	Answer
A	Narrow-band FM modulation achieved by filtering one sideband from the audio before frequency modulating the carrier
B	Spread spectrum modulation achieved by applying FM modulation following single sideband amplitude modulation
C	Amplitude modulation in which one complete sideband and a portion of the other are transmitted
D	A type of modulation in which one sideband is inverted

10. - E2C09

What type of equipment is commonly used to implement an amateur radio mesh network?

Select	Answer
A	An optical cable connection between the USB ports of 2 separate computers
B	A 2 meter VHF transceiver with a 1200 baud modem
C	A wireless router running custom firmware
D	A 440 MHz transceiver with a 9600 baud modem

11. - E2D09

What type of modulation is used for JT65 contacts?

Select	Answer
A	RTTY
B	IEEE 802.11
C	Multi-tone AFSK
D	PSK

12. - E2E08

Which of the following HF digital modes can be used to transfer binary files?

Select	Answer
A	PACTOR
B	AMTOR
C	RTTY
D	Hellschreiber

13. - E3A07

Atmospheric ducts capable of propagating microwave signals often form over what geographic feature?

Select	Answer
A	Urban areas
B	Bodies of water
C	Mountain ranges
D	Forests

14. - E3B02

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

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

15. - E3C08

What does the space weather term G5 mean?

Select	Answer
A	Moderate solar wind
B	Waning sunspot numbers
C	An extreme geomagnetic storm
D	Very low solar activity

16. - E4A08

Which of the following measures SWR?

Select	Answer
A	A Q meter
B	An ohmmeter
C	An antenna analyzer
D	A spectrum analyzer

17. - E4B06

How much power is being absorbed by the load when a directional power meter connected between a transmitter and a terminating load reads 100 watts forward power and 25 watts reflected power?

Select	Answer
A	100 watts
B	75 watts
C	125 watts
D	25 watts

18. - E4C06

A CW receiver with the AGC off has an equivalent input noise power density of -174 dBm/Hz. What would be the level of an unmodulated carrier input to this receiver that would yield an audio output SNR of 0 dB in a 400 Hz noise bandwidth?

Select	Answer
A	-174 dBm
B	-164 dBm
C	-148 dBm
D	-155 dBm

19. - E4D04

Which of the following may reduce or eliminate intermodulation interference in a repeater caused by another transmitter operating in close proximity?

Select	Answer
A	Utilizing a Class D final amplifier
B	A properly terminated circulator at the output of the repeater's transmitter
C	Utilizing a Class C final amplifier
D	A band-pass filter in the feed line between the transmitter and receiver

20. - E4E03

Which of the following signals might a receiver noise blanker be able to remove from desired signals?

Select	Answer
A	Signals that are constant at all IF levels
B	Signals that appear across a wide bandwidth
C	Signals that have a sharply peaked frequency distribution
D	Signals that appear at one IF but not another

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	7.12 MHz
B	7.12 kHz
C	23.5 kHz
D	23.5 MHz

22. - E5B05

What happens to the magnitude of a pure reactance when it is converted to a susceptance?

Select	Answer
A	The sign is reversed
B	It becomes the reciprocal
C	It is unchanged
D	It is shifted by 90 degrees

23. - E5C11

Which point in Figure E5-1 best represents the impedance of a series circuit consisting of a 300-ohm resistor and an 18-microhenry inductor at 3.505 MHz?

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

24. - E5D15

What is the power factor of an RL circuit having a 45-degree phase angle between the voltage and the current?

Select	Answer
A	0.5
B	0.866
C	1.0
D	0.707

25. - E6A09

What is a depletion-mode FET?

Select	Answer
A	Any FET without a channel
B	An FET that has no current flow between source and drain when no gate voltage is applied
C	Any FET for which holes are the majority carriers
D	An FET that exhibits a current flow between source and drain when no gate voltage is applied

26. - E6B08

Which of the following is a Schottky barrier diode?

Select	Answer
A	Thermionic emission diode
B	PIN junction
C	Metal-semiconductor junction
D	Electrolytic rectifier

27. - E6C07

What best describes a pull-up or pull-down resistor?

Select	Answer
A	A resistor connected to an op-amp output that prevents signals from exceeding the power supply voltage
B	A resistor that ensures that an oscillator frequency does not drift
C	A resistor in a keying circuit used to reduce key clicks
D	A resistor connected to the positive or negative supply line used to establish a voltage when an input or output is an open circuit

28. - E6D09

What devices are commonly used as VHF and UHF parasitic suppressors at the input and output terminals of a transistor HF amplifier?

Select	Answer
A	Steel-core toroids
B	Electrolytic capacitors
C	Ferrite beads
D	Butterworth filters

29. - E6E01

Why is gallium arsenide (GaAs) useful for semiconductor devices operating at UHF and higher frequencies?

Select	Answer
A	Higher noise figures
B	Lower junction voltage drop
C	Higher electron mobility
D	Lower transconductance

30. - E6F04

What is the photovoltaic effect?

Select	Answer
A	The tendency of a battery to discharge when exposed to light
B	The conversion of electrical energy to mechanical energy
C	The conversion of voltage to current when exposed to light
D	The conversion of light to electrical energy

31. - E7A07

What logical operation does a NAND gate perform?

Select	Answer
A	It produces logic 0 at its output only when all inputs are logic 0
B	It produces logic 0 at its output only when all inputs are logic 1
C	It produces logic 1 at its output only when all inputs are logic 1
D	It produces logic 0 at its output if some but not all inputs are logic 1

32. - E7B17

Why are odd-order rather than even-order intermodulation distortion products of concern in linear power amplifiers?

Select	Answer
A	Because they are relatively close in frequency to the desired signal
B	Because they invert the sidebands causing distortion
C	Because they maintain the sidebands, thus causing multiple duplicate signals
D	Because they are relatively far in frequency from the desired signal

33. - E7C12

What is one advantage of a Pi-matching network over an L-matching network consisting of a single inductor and a single capacitor?

Select	Answer
A	Pi-networks provide balanced input and output
B	The Q of Pi-networks can be controlled
C	Pi-networks are more stable
D	L-networks cannot perform impedance transformation

34. - E7D12

What is the dropout voltage of an analog voltage regulator?

Select	Answer
A	Maximum that the output voltage may decrease at rated load
B	Maximum output voltage drops when the input voltage is varied over its specified range
C	Minimum input-to-output voltage required to maintain regulation
D	Minimum input voltage for rated power dissipation

35. - E7E07

What is meant by the term "baseband" in radio communications?

Select	Answer
A	The unmodulated bandwidth of the transmitted signal
B	The frequency range occupied by a message signal prior to modulation
C	The basic oscillator frequency in an FM transmitter that is multiplied to increase the deviation and carrier frequency
D	The lowest frequency band that the transmitter or receiver covers

36. - E7F03

What type of digital signal processing filter is used to generate an SSB signal?

Select	Answer
A	A notch filter
B	An adaptive filter
C	An elliptical filter
D	A Hilbert-transform filter

37. - E7G05

How can unwanted ringing and audio instability be prevented in an op-amp RC audio filter circuit?

Select	Answer
A	Restrict both gain and Q
B	Increase both gain and Q
C	Restrict gain but increase Q
D	Restrict Q but increase gain

38. - E7H11

What are the major spectral impurity components of direct digital synthesizers?

Select	Answer
A	Spurious signals at discrete frequencies
B	Digital conversion noise
C	Nyquist limit noise
D	Broadband noise

39. - E8A01

What is the name of the process that shows that a square wave is made up of a sine wave plus all its odd harmonics?

Select	Answer
A	Differential analysis
B	Numerical analysis
C	Vector analysis
D	Fourier analysis

40. - E8B05

What is the deviation ratio of an FM-phone signal having a maximum frequency swing of plus-or-minus 5 kHz when the maximum modulation frequency is 3 kHz?

Select	Answer
A	0.167
B	0.6
C	1.67
D	60

41. - E8C07

What is the bandwidth of a 4800-Hz frequency shift, 9600-baud ASCII FM transmission?

Select	Answer
A	5.76 kHz
B	9.6 kHz
C	15.36 kHz
D	4.8 kHz

42. - E8D09

What is considered an acceptable maximum IMD level for an idling PSK signal?

Select	Answer
A	+15 dB
B	-20 dB
C	-30 dB
D	+10 dB

43. - E9A01

What is an isotropic antenna?

Select	Answer
A	A spacecraft antenna used to direct signals toward Earth
B	A horizontally polarized antenna used to compare Yagi antennas
C	A grounded antenna used to measure Earth conductivity
D	A theoretical, omnidirectional antenna used as a reference for antenna gain

44. - E9B06

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

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

45. - E9C08

What is a folded dipole antenna?

Select	Answer
A	A dipole configured to provide forward gain
B	A type of ground-plane antenna
C	A dipole one-quarter wavelength long
D	A half-wave dipole with an additional parallel wire connecting its two ends

46. - E9D08

What happens as the Q of an antenna increases?

Select	Answer
A	Gain is reduced
B	SWR bandwidth increases
C	SWR bandwidth decreases
D	More common-mode current is present on the feed line

47. - E9E09

Which of the following is used to shunt-feed a grounded tower at its base?

Select	Answer
A	Hairpin match
B	Gamma match
C	Double-bazooka match
D	All these choices are correct

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

49. - E9G02

What type of coordinate system is used in a Smith chart?

Select	Answer
A	Resistance lines and reactance chords
B	Voltage lines and current chords
C	Voltage circles and current arcs
D	Resistance circles and reactance arcs

50. - E9H08

What is the function of a sense antenna?

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

Figure E5-1

Figure E9-2