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

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1. - E0A06

Why are there separate electric (E) and magnetic (H) field MPE limits?

Select	Answer
A	All these choices are correct
B	The body reacts to electromagnetic radiation from both the E and H fields
C	Ground reflections and scattering make the field strength vary with location
D	E field and H field radiation intensity peaks can occur at different locations

2. - E1A06

Where must the carrier frequency of a CW signal be set to comply with FCC rules for 60 meter operation?

Select	Answer
A	At the lowest frequency of the channel
B	At the center frequency of the channel
C	On any frequency where the signal's sidebands are within the channel
D	At the highest frequency of the channel

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 letter of intent must be filed with the Environmental Protection Agency
C	A proposal must be submitted to the National Park Service
D	An Environmental Assessment must be submitted to the FCC

4. - E1C06

Which of the following is required in order to operate in accordance with CEPT rules in foreign countries where permitted?

Select	Answer
A	You must identify in the official language of the country in which you are operating
B	The U.S. embassy must approve of your operation
C	You must bring a copy of FCC Public Notice DA 16-1048
D	You must append "/CEPT" to your call sign

5. - E1D02

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

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

6. - E1E08

To which of the following examinees may a VE not administer an examination?

Select	Answer
A	Employees of the VE
B	Friends of the VE
C	All these choices are correct
D	Relatives of the VE as listed in the FCC rules

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 additional spectrum for personal use
D	To provide for experimental amateur communications

8. - E2A06

What are Keplerian elements?

Select	Answer
A	Phase reversing elements in a Yagi antenna
B	Parameters that define the orbit of a satellite
C	High-emission heater filaments used in magnetron tubes
D	Encrypting codes used for spread spectrum modulation

9. - E2B01

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

Select	Answer
A	120
B	60
C	90
D	30

10. - E2C02

Which of the following best describes the term self-spotting? in connection with HF contest operating?

Select	Answer
A	An automatic method for rapidly zero beating or tuning to a station's frequency before calling that station
B	The acceptable practice of manually posting the call signs of stations on a spotting network
C	A manual technique for rapidly zero beating or tuning to a station's frequency before calling that station
D	The often-prohibited practice of posting one's own call sign and frequency on a spotting network

11. - E2D11

Which of the following data are used by the APRS network to communicate station location?

Select	Answer
A	Time and frequency
B	Polar coordinates
C	Latitude and longitude
D	Radio direction finding spectrum analysis

12. - E2E12

How do ALE stations establish contact?

Select	Answer
A	ALE radios send a constant tone code to establish a frequency for future use
B	ALE radios monitor an internet site for the frequency they are being paged on
C	ALE constantly scans a list of frequencies, activating the radio when the designated call sign is received
D	ALE radios activate when they hear their signal echoed by back scatter

13. - E3A10

Which type of atmospheric structure can create a path for microwave propagation?

Select	Answer
A	Wind shear
B	The jet stream
C	Temperature inversion
D	Dust devil

14. - E3B05

Which amateur bands typically support long-path propagation?

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

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 peaks at roughly 14 MHz
C	It stays the same
D	It increases

16. - E4A01

Which of the following limits the highest frequency signal that can be accurately displayed on a digital oscilloscope?

Select	Answer
A	All these choices are correct
B	Amount of memory
C	Q of the circuit
D	Sampling rate of the analog-to-digital converter

17. - E4B08

Which of the following can be used to measure the Q of a series-tuned circuit?

Select	Answer
A	The bandwidth of the circuit's frequency response
B	The resonant frequency of the circuit
C	The inductance to capacitance ratio
D	The frequency shift

18. - E4C01

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

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

19. - E4D02

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

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

20. - E4E01

What problem can occur when using an automatic notch filter (ANF) to remove interfering carriers while receiving CW signals?

Select	Answer
A	Removal of the CW signal as well as the interfering carrier
B	Ringing in the DSP filter will completely remove the spaces between the CW characters
C	Received CW signals will appear to be modulated at the DSP clock frequency
D	Any nearby signal passing through the DSP system will overwhelm the desired signal

21. - E5A05

What is the result of increasing the Q of an impedance-matching circuit?

Select	Answer
A	Matching bandwidth is increased
B	It has no effect on impedance matching
C	Matching bandwidth is decreased
D	Matching range is increased

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 is shifted by 90 degrees
C	It becomes the reciprocal
D	It is unchanged

23. - E5C07

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

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

24. - E5D08

How many watts are consumed in a circuit having a power factor of 0.6 if the input is 200VAC at 5 amperes?

Select	Answer
A	600 watts
B	1600 watts
C	1000 watts
D	200 watts

25. - E6A02

Which of the following semiconductor materials contains excess free electrons?

Select	Answer
A	Insulated gate
B	Bipolar
C	N-type
D	P-type

26. - E6B09

What is a common use for point-contact diodes?

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

27. - E6C02

What happens when the level of a comparator's input signal crosses the threshold?

Select	Answer
A	The comparator enters latch-up
B	The IC input can be damaged
C	The feedback loop becomes unstable
D	The comparator changes its output state

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	Ferrite beads
C	Butterworth filters
D	Electrolytic capacitors

29. - E6E10

What advantage does surface-mount technology offer at RF compared to using through-hole components?

Select	Answer
A	All these choices are correct
B	Smaller circuit area
C	Shorter circuit-board traces
D	Components have less parasitic inductance and capacitance

30. - E6F05

Which describes an optical shaft encoder?

Select	Answer
A	A device for generating RTTY signals by means of a rotating light source
B	A digital encryption device often used to encrypt spacecraft control signals
C	A device that detects rotation of a control by interrupting a light source with a patterned wheel
D	A device that measures the strength of a beam of light using analog to digital conversion

31. - E7A03

Which of the following can divide the frequency of a pulse train by 2?

Select	Answer
A	An XOR gate
B	A multiplexer
C	An OR gate
D	A flip-flop

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. - E7C04

How does an impedance-matching circuit transform a complex impedance to a resistive impedance?

Select	Answer
A	It introduces negative resistance to cancel the resistive part of impedance
B	Reactive currents are dissipated in matched resistances
C	It cancels the reactive part of the impedance and changes the resistive part to a desired value
D	It introduces transconductance to cancel the reactive part of impedance

34. - E7D15

What is the purpose of a step-start circuit in a high-voltage power supply?

Select	Answer
A	To allow for remote control of the power supply
B	To allow the filter capacitors to charge gradually
C	To provide a dual-voltage output for reduced power applications
D	To compensate for variations of the incoming line voltage

35. - E7E09

What occurs when an excessive amount of signal energy reaches a mixer circuit?

Select	Answer
A	Spurious mixer products are generated
B	A beat frequency is generated
C	Mixer blanking occurs
D	Automatic limiting occurs

36. - E7F07

What function is performed by a Fast Fourier Transform?

Select	Answer
A	Converting digital signals to analog form
B	Converting digital signals from the time domain to the frequency domain
C	Converting analog signals to digital form
D	Converting 8-bit data to 16-bit data

37. - E7G12

What is an operational amplifier?

Select	Answer
A	A high-gain, direct-coupled differential amplifier with very high input impedance and very low output impedance
B	A digital audio amplifier whose characteristics are determined by components external to the amplifier
C	An amplifier used to increase the average output of frequency modulated amateur signals to the legal limit
D	A RF amplifier used in the UHF and microwave regions

38. - E7H05

How is positive feedback supplied in a Pierce oscillator?

Select	Answer
A	Through a quartz crystal
B	Through a neutralizing capacitor
C	Through a tapped coil
D	Through link coupling

39. - E8A05

What of the following instruments would be the most accurate for measuring the RMS voltage of a complex waveform?

Select	Answer
A	A D'Arsonval meter
B	An absorption wave meter
C	A grid dip meter
D	A true-RMS calculating meter

40. - E8B03

What is the modulation index of an FM-phone signal having a maximum frequency deviation of 3000 Hz either side of the carrier frequency when the modulating frequency is 1000 Hz?

Select	Answer
A	0.3
B	3000
C	3
D	1000

41. - E8C10

How may data rate be increased without increasing bandwidth?

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

42. - E8D03

How does the spread spectrum technique of frequency hopping work?

Select	Answer
A	The frequency of the transmitted signal is changed very rapidly according to a pseudorandom sequence also used by the receiving station
B	If interference is detected by the receiver it will signal the transmitter to wait until the frequency is clear
C	If interference is detected by the receiver it will signal the transmitter to change frequencies
D	A binary bit stream is used to shift the phase of an RF carrier very rapidly in a pseudorandom sequence

43. - E9A10

Which of the following improves the efficiency of a ground-mounted quarter-wave vertical antenna?

Select	Answer
A	Installing a radial system
B	Shortening the radiating element
C	All these choices are correct
D	Isolating the coax shield from ground

44. - E9B08

What is the far field of an antenna?

Select	Answer
A	The region of the ionosphere where radiated power is not refracted
B	The region where radiated power dissipates over a specified time period
C	The region where the shape of the antenna pattern is independent of distance
D	The region where radiated field strengths are constant

45. - E9C02

What is the radiation pattern of two 1/4-wavelength vertical antennas spaced 1/4 wavelength apart and fed 90 degrees out of phase?

Select	Answer
A	A figure-8 end-fire along the axis of the array
B	Cardioid
C	A figure-8 broadside to the axis of the array
D	Omni-directional

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 minimize the Q
C	To minimize losses
D	To lower the radiation angle

47. - E9E07

What parameter describes the interactions at the load end of a mismatched transmission line?

Select	Answer
A	Dielectric constant
B	Velocity factor
C	Reflection coefficient
D	Characteristic impedance

48. - E9F02

Which of the following has the biggest effect on the velocity factor of a transmission line?

Select	Answer
A	The line length
B	Dielectric materials used in the line
C	The center conductor resistivity
D	The termination impedance

49. - E9G03

Which of the following is often determined using a Smith chart?

Select	Answer
A	Beam headings and radiation patterns
B	Satellite azimuth and elevation bearings
C	Impedance and SWR values in transmission lines
D	Trigonometric functions

50. - E9H04

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

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