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 at which RF energy is absorbed by the body
C	The rate of RF energy reflected from stationary terrain
D	Signal Amplification Rating

2. - E1A10

If an amateur station is installed aboard a ship or aircraft, what condition must be met before the station is operated?

Select	Answer
A	The amateur operator must have an FCC Marine or Aircraft endorsement on his or her amateur license
B	The amateur station must have a power supply that is completely independent of the main ship or aircraft power supply
C	Its operation must be approved by the master of the ship or the pilot in command of the aircraft
D	The amateur station operator must agree not to transmit when the main radio of the ship or aircraft is in use

3. - E1B04

What must be done before placing an amateur station within an officially designated wilderness area or wildlife preserve, or an area listed in the National Register of Historic Places?

Select	Answer
A	A form FSD-15 must be submitted to the Department of the Interior
B	A proposal must be submitted to the National Park Service
C	An Environmental Assessment must be submitted to the FCC
D	A letter of intent must be filed with the Environmental Protection Agency

4. - E1C14

How long must an operator wait after filing a notification with the Utilities Technology Council (UTC) before operating on the 2200 meter or 630 meter band?

Select	Answer
A	Operations may commence immediately, and may continue unless interference is reported by the UTC
B	Operators must not operate until approval is received
C	Operators may not operate until a test signal has been transmitted in coordination with the local power company
D	Operators may operate after 30 days, providing they have not been told that their station is within 1 km of PLC systems using those frequencies

5. - E1D09

Which UHF amateur bands have frequencies authorized for space stations?

Select	Answer
A	70 cm and 33 cm
B	70 cm and 13 cm
C	33 cm and 13 cm
D	70 cm only

6. - E1E05

What is the minimum passing score on all amateur operator license examinations?

Select	Answer
A	Minimum passing score of 70%
B	Minimum passing score of 74%
C	Minimum passing score of 80%
D	Minimum passing score of 77%

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 purchased in used condition from an amateur operator and is sold to another amateur operator for use at that operator's station
C	It was imported from a manufacturer in another country and was certificated by that country's government
D	It was imported from a manufacturer in a country that does not require certification of RF power amplifiers

8. - E2A09

What do the terms L band and S band specify regarding satellite communications?

Select	Answer
A	The 23 centimeter and 13 centimeter bands
B	Which sideband to use
C	The 2 meter and 70 centimeter bands
D	FM and Digital Store-and-Forward systems

9. - E2B05

Which of the following describes the use of vestigial sideband in analog fast-scan TV transmissions?

Select	Answer
A	Vestigial sideband provides high frequency emphasis to sharpen the picture
B	The vestigial sideband contains chroma information
C	Vestigial sideband reduces bandwidth while allowing for simple video detector circuitry
D	The vestigial sideband carries the audio information

10. - E2C12

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

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

11. - E2D10

How can an APRS station be used to help support a public service communications activity?

Select	Answer
A	An APRS station with a Global Positioning System unit can automatically transmit information to show a mobile station's position during the event
B	APRS stations with General Personnel Scanners can automatically relay the participant numbers and time as they pass the check points
C	An APRS station with an emergency medical technician can automatically transmit medical data to the nearest hospital
D	All these choices are correct

12. - E2E02

What do the letters FEC mean as they relate to digital operation?

Select	Answer
A	Fatal Error Correction
B	Forward Error Correction
C	Final Error Correction
D	First Error Correction

13. - E3A09

Which of the following frequency ranges is most suited for meteor scatter communications?

Select	Answer
A	1.8 MHz - 1.9 MHz
B	28 MHz - 148 MHz
C	220 MHz - 450 MHz
D	10 MHz - 14 MHz

14. - E3B05

Which amateur bands typically support long-path propagation?

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

15. - E3C11

What does VOACAP software model?

Select	Answer
A	AC current and impedance
B	VHF radio propagation
C	AC voltage and impedance
D	HF propagation

16. - E4A04

How is the compensation of an oscilloscope probe typically adjusted?

Select	Answer
A	A DC voltage standard is displayed and the probe is adjusted until the displayed voltage is accurate
B	A square wave is displayed and the probe is adjusted until the horizontal portions of the displayed wave are as nearly flat as possible
C	A high frequency sine wave is displayed and the probe is adjusted for maximum amplitude
D	A frequency standard is displayed and the probe is adjusted until the deflection time is accurate

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 AF signals having non-harmonically related frequencies and observe the RF output with a spectrum analyzer
D	Modulate the transmitter using two RF signals having harmonically related frequencies and observe the RF output with a logic analyzer

18. - E4C01

What is an effect of excessive phase noise in a receiver's local oscillator?

Select	Answer
A	It can combine with strong signals on nearby frequencies to generate interference
B	It can affect the receiver's frequency calibration
C	It limits the receiver's ability to receive strong signals
D	It decreases receiver third-order intercept point

19. - E4D05

What transmitter frequencies would cause an intermodulation-product signal in a receiver tuned to 146.70 MHz when a nearby station transmits on 146.52 MHz?

Select	Answer
A	146.34 MHz and 146.61 MHz
B	146.88 MHz and 146.34 MHz
C	146.10 MHz and 147.30 MHz
D	173.35 MHz and 139.40 MHz

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. - E5A11

What is the half-power bandwidth of a resonant circuit that has a resonant frequency of 7.1 MHz and a Q of 150?

Select	Answer
A	23.67 kHz
B	315.6 Hz
C	47.3 kHz
D	157.8 Hz

22. - E5B06

What is susceptance?

Select	Answer
A	The magnetic impedance of a circuit
B	A measure of the efficiency of a transformer
C	The imaginary part of admittance
D	The ratio of magnetic field to electric field

23. - E5C07

Where is the impedance of a pure resistance plotted on rectangular coordinates?

Select	Answer
A	On the horizontal axis
B	On a line through the origin, slanted at 45 degrees
C	On a horizontal line, offset vertically above the horizontal axis
D	On the vertical axis

24. - E5D11

What is the power factor of an RL circuit having a 60-degree phase angle between the voltage and the current?

Select	Answer
A	1.73
B	0.866
C	1.414
D	0.5

25. - E6A07

Which of the following indicates that a silicon NPN junction transistor is biased on?

Select	Answer
A	Base-to-emitter resistance of approximately 6 to 7 ohms
B	Base-to-emitter resistance of approximately 0.6 to 0.7 ohms
C	Base-to-emitter voltage of approximately 6 to 7 volts
D	Base-to-emitter voltage of approximately 0.6 to 0.7 volts

26. - E6B03

What type of bias is required for an LED to emit light?

Select	Answer
A	Inductive bias
B	Forward bias
C	Zero bias
D	Reverse bias

27. - E6C05

What is an advantage of CMOS logic devices over TTL devices?

Select	Answer
A	Lower distortion
B	Immune to damage from static discharge
C	Differential output capability
D	Lower power consumption

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. - E6E02

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

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

30. - E6F03

What is the most common configuration of an optoisolator or optocoupler?

Select	Answer
A	A lens and a photomultiplier
B	A frequency modulated helium-neon laser
C	An amplitude modulated helium-neon laser
D	An LED and a phototransistor

31. - E7A06

What is a characteristic of a monostable multivibrator?

Select	Answer
A	It switches momentarily to the opposite binary state and then returns to its original state after a set time
B	It stores one bit of data in either a 0 or 1 state
C	It maintains a constant output voltage, regardless of variations in the input voltage
D	It produces a continuous square wave oscillating between 1 and 0

32. - E7B12

What type of amplifier circuit is shown in Figure E7-1?

Select	Answer
A	Common base
B	Common emitter
C	Common collector
D	Emitter follower

33. - E7C08

Which of the following factors has the greatest effect on the bandwidth and response shape of a crystal ladder filter?

Select	Answer
A	The relative frequencies of the individual crystals
B	The gain of the RF stage preceding the filter
C	The amplitude of the signals passing through the filter
D	The DC voltage applied to the quartz crystal

34. - E7D10

What is the primary reason that a high-frequency switching type high-voltage power supply can be both less expensive and lighter in weight than a conventional power supply?

Select	Answer
A	It uses a large power factor compensation capacitor to recover power from the unused portion of the AC cycle
B	It uses a diode bridge rectifier for increased output
C	The high frequency inverter design uses much smaller transformers and filter components for an equivalent power output
D	The inverter design does not require any output filtering

35. - E7E07

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

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

36. - E7F08

What is the function of decimation?

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

37. - E7G09

What will be the output voltage of the circuit shown in Figure E7-3 if R1 is 1000 ohms, RF is 10,000 ohms, and 0.23 volts DC is applied to the input?

Select	Answer
A	-0.23 volts
B	2.3 volts
C	-2.3 volts
D	0.23 volts

38. - E7H10

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

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

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	Numerical analysis
B	Differential analysis
C	Fourier analysis
D	Vector 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	0.6
B	0.167
C	60
D	1.67

41. - E8C08

How does ARQ accomplish error correction?

Select	Answer
A	If errors are detected, a retransmission is requested
B	Special polynomial codes provide automatic correction
C	Special binary codes provide automatic correction
D	If errors are detected, redundant data is substituted

42. - E8D02

What spread spectrum communications technique uses a high-speed binary bit stream to shift the phase of an RF carrier?

Select	Answer
A	Phase compandored spread spectrum
B	Frequency hopping
C	Binary phase-shift keying
D	Direct sequence

43. - E9A12

How much gain does an antenna have compared to a 1/2-wavelength dipole when it has 6 dB gain over an isotropic antenna?

Select	Answer
A	2.79 dB
B	6.0 dB
C	8.15 dB
D	3.85 dB

44. - E9B10

What is the principle of a Method of Moments analysis?

Select	Answer
A	A wire is modeled as a series of segments, each having a uniform value of current
B	A wire is modeled as a single sine-wave current generator
C	A wire is modeled as a single sine-wave voltage source
D	A wire is modeled as a series of segments, each having a distinct value of voltage across it

45. - E9C12

Which of the following describes an Extended Double Zepp antenna?

Select	Answer
A	A wideband vertical antenna constructed from precisely tapered aluminum tubing
B	A center-fed 1.25-wavelength antenna (two 5/8-wave elements in phase)
C	An end-fed folded dipole antenna
D	A portable antenna erected using two push support poles

46. - E9D08

What happens as the Q of an antenna increases?

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

47. - E9E05

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

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

48. - E9F05

What is the approximate physical length of a solid polyethylene dielectric coaxial transmission line that is electrically 1/4 wavelength long at 14.1 MHz?

Select	Answer
A	5.3 meters
B	10.6 meters
C	4.3 meters
D	3.5 meters

49. - E9G01

Which of the following can be calculated using a Smith chart?

Select	Answer
A	Radiation resistance
B	Radio propagation
C	Antenna radiation pattern
D	Impedance along transmission lines

50. - E9H08

What is the function of a sense antenna?

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

Figure E7-1

Figure E7-3