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

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1. - E0A11

Which of the following injuries can result from using high-power UHF or microwave transmitters?

Select	Answer
A	Localized heating of the body from RF exposure in excess of the MPE limits
B	Blood clotting from the intense magnetic field
C	Ingestion of ozone gas from the cooling system
D	Hearing loss caused by high voltage corona discharge

2. - E1A14

Except in some parts of Alaska, what is the maximum power permitted on the 630 meter band?

Select	Answer
A	5 watts EIRP
B	100 watts PEP
C	1 watt EIRP
D	50 watts PEP

3. - E1B12

What must the control operator of a repeater operating in the 70 cm band do if a radiolocation system experiences interference from that repeater?

Select	Answer
A	All these choices are correct
B	File an FAA NOTAM (Notice to Airmen) with the repeater system's ERP, call sign, and six-character grid locator
C	Cease operation or make changes to the repeater to mitigate the interference
D	Reduce the repeater antenna HAAT (Height Above Average Terrain)

4. - E1C03

How do the control operator responsibilities of a station under automatic control differ from one under local control?

Select	Answer
A	Under local control there is no control operator
B	Under automatic control the control operator is not required to be present at the control point
C	Under automatic control there is no control operator
D	Under local control a control operator is not required to be present at a control point

5. - E1D11

Which amateur stations are eligible to operate as Earth stations?

Select	Answer
A	Any amateur station whose licensee has filed a pre-space notification with the FCC's International Bureau
B	Any amateur station, subject to the privileges of the class of operator license held by the control operator
C	Only those of General, Advanced or Amateur Extra Class operators
D	Only those of Amateur Extra Class operators

6. - E1E03

What is a Volunteer Examiner Coordinator?

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

7. - E1F09

Which of the following conditions apply when transmitting spread spectrum emissions?

Select	Answer
A	A station transmitting SS emission must not cause harmful interference to other stations employing other authorized emissions
B	All these choices are correct
C	The transmission must not be used to obscure the meaning of any communication
D	The transmitting station must be in an area regulated by the FCC or in a country that permits SS emissions

8. - E2A03

How is the signal inverted by an inverting linear transponder?

Select	Answer
A	The signal is detected and remodulated on the reverse sideband
B	The signal is passed through a mixer and the difference rather than the sum is transmitted
C	The signal is reduced to I and Q components and the Q component is filtered out
D	The signal is passed through a non-linear filter

9. - E2B01

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

Select	Answer
A	30
B	60
C	90
D	120

10. - E2C06

During a VHF/UHF contest, in which band segment would you expect to find the highest level of SSB or CW activity?

Select	Answer
A	In the weak signal segment of the band, with most of the activity near the calling frequency
B	In the middle of the band, usually 25 kHz above the national calling frequency
C	At the top of each band, usually in a segment reserved for contests
D	In the middle of each band, usually on the national calling frequency

11. - E2D11

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

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

12. - E2E11

What is the difference between direct FSK and audio FSK?

Select	Answer
A	Direct FSK occupies less bandwidth
B	Direct FSK can transmit faster baud rates
C	Direct FSK applies the data signal to the transmitter VFO, while AFSK transmits tones via phone
D	Only direct FSK can be decoded by computer

13. - E3A12

What is the cause of auroral activity?

Select	Answer
A	The interaction in the E layer of charged particles from the Sun with the Earth's magnetic field
B	Meteor showers concentrated in the extreme northern and southern latitudes
C	An extreme low-pressure area in the polar regions
D	The interaction in the F2 layer between the solar wind and the Van Allen belt

14. - E3B05

Which amateur bands typically support long-path propagation?

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

15. - E3C09

How does the intensity of an X3 flare compare to that of an X2 flare?

Select	Answer
A	50 percent greater
B	Twice as great
C	10 percent greater
D	Four times as great

16. - E4A07

Which of the following is an advantage of using an antenna analyzer compared to an SWR bridge to measure antenna SWR?

Select	Answer
A	Antenna analyzers do not need an external RF source
B	Antenna analyzers automatically tune your antenna for resonance
C	Antenna analyzers display a time-varying representation of the modulation envelope
D	All these choices are correct

17. - E4B01

Which of the following factors most affects the accuracy of a frequency counter?

Select	Answer
A	Decade divider accuracy
B	Temperature coefficient of the logic
C	Input attenuator accuracy
D	Time base accuracy

18. - E4C10

What is an advantage of having a variety of receiver IF bandwidths from which to select?

Select	Answer
A	Multiple frequencies can be received simultaneously if desired
B	Receive bandwidth can be set to match the modulation bandwidth, maximizing signal-to-noise ratio and minimizing interference
C	Receiver power consumption can be reduced when wider bandwidth is not required
D	The noise figure of the RF amplifier can be adjusted to match the modulation type, thus increasing receiver sensitivity

19. - E4D07

Which of the following reduces the likelihood of receiver desensitization?

Select	Answer
A	Decrease the RF bandwidth of the receiver
B	Raise the receiver IF frequency
C	Switch from fast AGC to slow AGC
D	Increase the receiver front end gain

20. - E4E08

What current flows equally on all conductors of an unshielded multi-conductor cable?

Select	Answer
A	Common-mode current
B	Return current
C	Reactive current only
D	Differential-mode current

21. - E5A01

What can cause the voltage across reactances in a series RLC circuit to be higher than the voltage applied to the entire circuit?

Select	Answer
A	Resistance
B	Resonance
C	Conductance
D	Capacitance

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 is unchanged
D	It becomes the reciprocal

23. - E5C06

What does the impedance 50-j25 represent?

Select	Answer
A	50 ohms resistance in series with 25 ohms inductive reactance
B	25 ohms resistance in series with 50 ohms capacitive reactance
C	50 ohms resistance in series with 25 ohms capacitive reactance
D	25 ohms resistance in series with 50 ohms inductive reactance

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	1.0
B	0.707
C	0.5
D	0.866

25. - E6A02

Which of the following semiconductor materials contains excess free electrons?

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

26. - E6B08

Which of the following is a Schottky barrier diode?

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

27. - E6C02

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

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

28. - E6D06

What core material property determines the inductance of an inductor?

Select	Answer
A	Reactivity
B	Resistance
C	Permeability
D	Thermal impedance

29. - E6E11

What is a characteristic of DIP packaging used for integrated circuits?

Select	Answer
A	A total of two rows of connecting pins placed on opposite sides of the package (Dual In-line Package)
B	Low leakage doubly insulated package
C	Package mounts in a direct inverted position
D	Two chips in each package (Dual In Package)

30. - E6F01

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

Select	Answer
A	Protons
B	Photons
C	Holes
D	Electrons

31. - E7A06

What is a characteristic of a monostable multivibrator?

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

32. - E7B05

What can be done to prevent unwanted oscillations in an RF power amplifier?

Select	Answer
A	Use a phase inverter in the output filter
B	Tune both the input and output for maximum power
C	Tune the stage for maximum SWR
D	Install parasitic suppressors and/or neutralize the stage

33. - E7C01

How are the capacitors and inductors of a low-pass filter Pi-network arranged between the network's input and output?

Select	Answer
A	A capacitor is connected between the input and ground, another capacitor is connected between the output and ground, and an inductor is connected between input and output
B	Two inductors are in series between the input and output, and a capacitor is connected between the two inductors and ground
C	An inductor is connected between the input and ground, another inductor is connected between the output and ground, and a capacitor is connected between the input and output
D	Two capacitors are in series between the input and output, and an inductor is connected between the two capacitors and ground

34. - E7D04

Which of the following types of linear voltage regulator usually make the most efficient use of the primary power source?

Select	Answer
A	A shunt current source
B	A series current source
C	A series regulator
D	A shunt regulator

35. - E7E11

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

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

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. - E7G02

What is ringing in a filter?

Select	Answer
A	An echo caused by a long time delay
B	Undesired oscillations added to the desired signal
C	Partial cancellation of the signal over a range of frequencies
D	A reduction in high frequency response

38. - E7H10

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

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

39. - E8A10

What is the purpose of a low-pass filter used in conjunction with a digital-to-analog converter?

Select	Answer
A	Lower the input bandwidth to increase the effective resolution
B	Remove harmonics from the output caused by the discrete analog levels generated
C	Improve accuracy by removing out-of-sequence codes from the input
D	All these choices are correct

40. - E8B02

How does the modulation index of a phase-modulated emission vary with RF carrier frequency?

Select	Answer
A	It does not depend on the RF carrier frequency
B	It increases as the RF carrier frequency increases
C	It varies with the square root of the RF carrier frequency
D	It decreases as the RF carrier frequency increases

41. - E8C08

How does ARQ accomplish error correction?

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

42. - E8D10

What are some of the differences between the Baudot digital code and ASCII?

Select	Answer
A	Baudot uses 7 data bits per character, ASCII uses 8; Baudot has no letters/figures shift code, ASCII uses 2 letters/figures shift codes
B	Baudot uses 5 data bits per character, ASCII uses 7 or 8; Baudot uses 2 characters as letters/figures shift codes, ASCII has no letters/figures shift code
C	Baudot uses 4 data bits per character, ASCII uses 7 or 8; Baudot uses 1 character as a letters/figures shift code, ASCII has no letters/figures code
D	Baudot uses 6 data bits per character, ASCII uses 7 or 8; Baudot has no letters/figures shift code, ASCII uses 2 letters/figures shift codes

43. - E9A10

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

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

44. - E9B07

How does the total amount of radiation emitted by a directional gain antenna compare with the total amount of radiation emitted from a theoretical isotropic antenna, assuming each is driven by the same amount of power?

Select	Answer
A	The radiation from the isotropic antenna is 2.15 dB stronger than that from the directional antenna
B	The total amount of radiation from the directional antenna is stronger by its front-to-back ratio
C	The total amount of radiation from the directional antenna is increased by the gain of the antenna
D	They are the same

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

46. - E9D02

How can linearly polarized Yagi antennas be used to produce circular polarization?

Select	Answer
A	Stack two Yagis fed 90 degrees out of phase to form an array with the respective elements in parallel planes
B	Arrange two Yagis perpendicular to each other with the driven elements at the same point on the boom fed 90 degrees out of phase
C	Arrange two Yagis collinear to each other with the driven elements fed 180 degrees out of phase
D	Stack two Yagis fed in phase to form an array with the respective elements in parallel planes

47. - E9E11

What is the primary purpose of phasing lines when used with an antenna having multiple driven elements?

Select	Answer
A	It ensures that each driven element operates in concert with the others to create the desired antenna pattern
B	It creates a low-angle radiation pattern
C	It allows single-band antennas to operate on other bands
D	It prevents reflected power from traveling back down the feed line and causing harmonic radiation from the transmitter

48. - E9F13

What impedance does a 1/4-wavelength transmission line present to a generator when the line is shorted at the far end?

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

49. - E9G05

Which of the following is a common use for a Smith chart?

Select	Answer
A	Determine the loss/100 feet of a transmission line, given the velocity factor and conductor materials
B	Determine the gain of an antenna given the physical and electrical parameters
C	Determine the length and position of an impedance matching stub
D	Determine the impedance of a transmission line, given the physical dimensions

50. - E9H03

What is Receiving Directivity Factor (RDF)?

Select	Answer
A	Relative directivity compared to a dipole
B	Forward gain compared to average gain over the entire hemisphere
C	Forward gain compared to the gain in the reverse direction
D	Relative directivity compared to isotropic