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

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1. - E0A03

Over what range of frequencies are the FCC human body RF exposure limits most restrictive?

Select	Answer
A	3 to 30 MHz
B	300 to 3000 MHz
C	30 to 300 MHz
D	300 kHz to 3 MHz

2. - E1A02

When using a transceiver that displays the carrier frequency of phone signals, which of the following displayed frequencies represents the lowest frequency at which a properly adjusted LSB emission will be totally within the band?

Select	Answer
A	3 kHz above the lower band edge
B	300 Hz above the lower band edge
C	The exact lower band edge
D	1 kHz above the lower band edge

3. - E1B07

To what type of regulations does PRB-1 apply?

Select	Answer
A	State and local zoning
B	Homeowners associations
C	Use of wireless devices in vehicles
D	FAA tower height limits

4. - E1C12

On what portion of the 630 meter band are phone emissions permitted?

Select	Answer
A	Only the top 3 kHz
B	The entire band
C	None
D	Only the bottom 3 kHz

5. - E1D12

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

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

6. - E1E03

What is a Volunteer Examiner Coordinator?

Select	Answer
A	An organization that has entered into an agreement with the FCC to coordinate, prepare, and administer amateur operator license examinations
B	The person who has entered into an agreement with the FCC to be the VE session manager
C	A person who has volunteered to prepare amateur operator license examinations
D	A person who has volunteered to administer amateur operator license examinations

7. - E1F01

On what frequencies are spread spectrum transmissions permitted?

Select	Answer
A	Only on amateur frequencies above 144 MHz
B	Only on amateur frequencies above 222 MHz
C	Only on amateur frequencies above 420 MHz
D	Only on amateur frequencies above 50 MHz

8. - E2A05

What do the letters in a satellite's mode designator specify?

Select	Answer
A	The location of the ground control station
B	Power limits for uplink and downlink transmissions
C	The polarization of uplink and downlink signals
D	The uplink and downlink frequency ranges

9. - E2B04

How is color information sent in analog SSTV?

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

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	HF frequencies where digital communications are permitted
C	The 60 meter band channel centered on 5373 kHz
D	Cable TV channels 41 through 43

11. - E2D09

What type of modulation is used for JT65 contacts?

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

12. - E2E07

Which of the following is a possible reason that attempts to initiate contact with a digital station on a clear frequency are unsuccessful?

Select	Answer
A	All these choices are correct
B	Another station you are unable to hear is using the frequency
C	The protocol version you are using is not supported by the digital station
D	Your transmit frequency is incorrect

13. - E3A04

What do Hepburn maps predict?

Select	Answer
A	Probability of tropospheric propagation
B	Sporadic E propagation
C	Likelihood of rain scatter along cold or warm fronts
D	Locations of auroral reflecting zones

14. - E3B03

What is the best time of day for transequatorial propagation?

Select	Answer
A	Afternoon or early evening
B	Morning
C	Late at night
D	Noon

15. - E3C12

How does the maximum range of ground-wave propagation change when the signal frequency is increased?

Select	Answer
A	It decreases
B	It increases
C	It stays the same
D	It peaks at roughly 14 MHz

16. - E4A08

Which of the following measures SWR?

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

17. - E4B11

Which of the following can be measured with a vector network analyzer?

Select	Answer
A	Input impedance
B	All these choices are correct
C	Output impedance
D	Reflection coefficient

18. - E4C08

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

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

19. - E4D02

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

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

20. - E4E03

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

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

21. - E5A07

What is the magnitude of the current at the input of a parallel RLC circuit at resonance?

Select	Answer
A	L/R
B	Minimum
C	R/L
D	Maximum

22. - E5B04

What is the time constant of a circuit having two 220-microfarad capacitors and two 1-megohm resistors, all in parallel?

Select	Answer
A	220 seconds
B	440 seconds
C	110 seconds
D	55 seconds

23. - E5C02

How are impedances described in polar coordinates?

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

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	1.414
B	0.5
C	0.866
D	1.73

25. - E6A11

In Figure E6-1, what is the schematic symbol for a P-channel junction FET?

Select	Answer
A	6
B	3
C	2
D	1

26. - E6B09

What is a common use for point-contact diodes?

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

27. - E6C03

What is tri-state logic?

Select	Answer
A	Proprietary logic devices manufactured by Tri-State Devices
B	Low-power logic devices designed to operate at 3 volts
C	Logic devices that utilize ternary math
D	Logic devices with 0, 1, and high-impedance output states

28. - E6D07

What is current in the primary winding of a transformer called if no load is attached to the secondary?

Select	Answer
A	Direct current
B	Excitation current
C	Stabilizing current
D	Magnetizing current

29. - E6E02

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

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

30. - E6F08

Why are optoisolators often used in conjunction with solid-state circuits when switching 120 VAC?

Select	Answer
A	Optoisolators provide a very high degree of electrical isolation between a control circuit and the circuit being switched
B	Optoisolators provide impedance matching between the control circuit and power circuit
C	Optoisolators eliminate the effects of reflected light in the control circuit
D	Optoisolators provide a low impedance link between a control circuit and a power circuit

31. - E7A11

What type of logic defines "1" as a high voltage?

Select	Answer
A	Negative logic
B	Assertive Logic
C	Reverse Logic
D	Positive Logic

32. - E7B14

Why are switching amplifiers more efficient than linear amplifiers?

Select	Answer
A	Switching amplifiers use push-pull circuits
B	The power transistor is at saturation or cutoff most of the time
C	Linear amplifiers have high gain resulting in higher harmonic content
D	Switching amplifiers operate at higher voltages

33. - E7C06

What are the distinguishing features of an elliptical filter?

Select	Answer
A	Extremely flat response over its pass band with gradually rounded stop band corners
B	Gradual passband rolloff with minimal stop band ripple
C	Extremely sharp cutoff with one or more notches in the stop band
D	Gradual passband rolloff with extreme stop band ripple

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 inverter design does not require any output filtering
D	The high frequency inverter design uses much smaller transformers and filter components for an equivalent power output

35. - E7E11

Which type of detector circuit is used for demodulating SSB signals?

Select	Answer
A	Product detector
B	Phase detector
C	Discriminator
D	Phase comparator

36. - E7F10

What aspect of receiver analog-to-digital conversion determines the maximum receive bandwidth of a Direct Digital Conversion SDR?

Select	Answer
A	Sample width in bits
B	Processor latency
C	Sample clock phase noise
D	Sample rate

37. - E7G03

What is the typical input impedance of an op-amp?

Select	Answer
A	1000 ohms
B	Very low
C	100 ohms
D	Very high

38. - E7H02

What is a microphonic?

Select	Answer
A	Changes in oscillator frequency due to mechanical vibration
B	Distortion caused by RF pickup on the microphone cable
C	Excess loading of the microphone by an oscillator
D	An IC used for amplifying microphone signals

39. - E8A04

What is "dither" with respect to analog-to-digital converters?

Select	Answer
A	A small amount of noise added to the input signal to allow more precise representation of a signal over time
B	An abnormal condition where the converter cannot settle on a value to represent the signal
C	An error caused by irregular quantization step size
D	A method of decimation by randomly skipping samples

40. - E8B11

What is digital time division multiplexing?

Select	Answer
A	Two or more data streams are assigned to discrete sub-carriers on an FM transmitter
B	Two or more signals are quadrature modulated to increase bandwidth efficiency
C	Two or more data streams share the same channel by transmitting time of transmission as the sub-carrier
D	Two or more signals are arranged to share discrete time slots of a data transmission

41. - E8C09

Which digital code allows only one bit to change between sequential code values?

Select	Answer
A	Binary Coded Decimal Code
B	Extended Binary Coded Decimal Interchange Code
C	Gray code
D	Excess 3 code

42. - E8D07

What is a common cause of overmodulation of AFSK signals?

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

43. - E9A07

What is the effective isotropic radiated power of a repeater station with 200 watts transmitter power output, 2 dB feed line loss, 2.8 dB duplexer loss, 1.2 dB circulator loss, and 7 dBi antenna gain?

Select	Answer
A	63.2 watts
B	252 watts
C	159 watts
D	632 watts

44. - E9B10

What is the principle of a Method of Moments analysis?

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

45. - E9C11

How is the far-field elevation pattern of a vertically polarized antenna affected by being mounted over seawater versus soil?

Select	Answer
A	The low-angle radiation decreases
B	The low-angle radiation increases
C	Fewer vertical angle lobes will be present
D	Additional higher vertical angle lobes will appear

46. - E9D04

Why should an HF mobile antenna loading coil have a high ratio of reactance to resistance?

Select	Answer
A	To swamp out harmonics
B	To lower the radiation angle
C	To minimize losses
D	To minimize the Q

47. - E9E08

What is a use for a Wilkinson divider?

Select	Answer
A	It is used to feed low-impedance loads from a high-impedance source
B	It is used to divide power equally between two 50-ohm loads while maintaining 50-ohm input impedance
C	It is used to feed high-impedance antennas from a low-impedance source
D	It divides the operating frequency of a transmitter signal so it can be used on a lower frequency band

48. - E9F08

Which of the following is a significant difference between foam dielectric coaxial cable and solid dielectric cable, assuming all other parameters are the same?

Select	Answer
A	Foam dielectric has lower safe operating voltage limits
B	All these choices are correct
C	Foam dielectric has higher velocity factor
D	Foam dielectric has lower loss per unit of length

49. - E9G02

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

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

50. - E9H01

When constructing a Beverage antenna, which of the following factors should be included in the design to achieve good performance at the desired frequency?

Select	Answer
A	Its overall length must not exceed 1/4 wavelength
B	It should be one or more wavelengths long
C	It must be mounted more than 1 wavelength above ground
D	It should be configured as a four-sided loop

Figure E6-1