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	300 kHz to 3 MHz
B	300 to 3000 MHz
C	30 to 300 MHz
D	3 to 30 MHz

2. - E1A04

With your transceiver displaying the carrier frequency of phone signals, you hear a DX station calling CQ on 3.601 MHz LSB. Is it legal to return the call using lower sideband on the same frequency?

Select	Answer
A	Yes, because the displayed frequency is within the 75 meter phone band segment
B	Yes, because the DX station initiated the contact
C	No, the sideband will extend beyond the edge of the phone band segment
D	No, U.S. stations are not permitted to use phone emissions below 3.610 MHz

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

4. - E1C11

Which of the following operating arrangements allows an FCC-licensed U.S. citizen to operate in many European countries, and alien amateurs from many European countries to operate in the U.S.?

Select	Answer
A	CEPT agreement
B	All these choices are correct
C	IARP agreement
D	ITU reciprocal license

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	Only those of Amateur Extra Class operators
C	Only those of General, Advanced or Amateur Extra Class operators
D	Any amateur station, subject to the privileges of the class of operator license held by the control operator

6. - E1E06

Who is responsible for the proper conduct and necessary supervision during an amateur operator license examination session?

Select	Answer
A	Each administering VE
B	The FCC
C	The VE session manager
D	The VEC coordinating the session

7. - E1F02

What privileges are authorized in the U.S. to persons holding an amateur service license granted by the government of Canada?

Select	Answer
A	All privileges of the Amateur Extra Class license
B	None, they must obtain a U.S. license
C	Full privileges, up to and including those of the Amateur Extra Class license, on the 80, 40, 20, 15, and 10 meter bands
D	The operating terms and conditions of the Canadian amateur service license, not to exceed U.S. Amateur Extra Class license privileges

8. - E2A07

Which of the following types of signals can be relayed through a linear transponder?

Select	Answer
A	SSB and SSTV
B	FM and CW
C	All these choices are correct
D	PSK and packet

9. - E2B02

How many horizontal lines make up a fast-scan (NTSC) television frame?

Select	Answer
A	30
B	60
C	1080
D	525

10. - E2C12

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

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

11. - E2D03

Which of the following digital modes is especially useful for EME communications?

Select	Answer
A	Olivia
B	JT65
C	PACTOR III
D	MSK144

12. - E2E04

What is indicated when one of the ellipses in an FSK crossed-ellipse display suddenly disappears?

Select	Answer
A	The receiver has drifted 5 kHz from the desired receive frequency
B	Selective fading has occurred
C	The mark and space signal have been inverted
D	One of the signal filters is saturated

13. - E3A14

What is meant by circularly polarized electromagnetic waves?

Select	Answer
A	Waves with a rotating electric field
B	Waves that circle the Earth
C	Waves produced by a loop antenna
D	Waves with an electric field bent into a circular shape

14. - E3B12

What is the primary characteristic of chordal hop propagation?

Select	Answer
A	Propagation across the geomagnetic equator
B	Signals reflected back toward the transmitting station
C	Propagation away from the great circle bearing between stations
D	Successive ionospheric refractions without an intermediate reflection from the ground

15. - E3C13

What type of polarization is best for ground-wave propagation?

Select	Answer
A	Horizontal
B	Circular
C	Vertical
D	Elliptical

16. - E4A09

Which of the following is good practice when using an oscilloscope probe?

Select	Answer
A	Never use a DC-coupled probe to measure an AC circuit
B	Never use a high-impedance probe to measure a low-impedance circuit
C	Keep the signal ground connection of the probe as short as possible
D	All these choices are correct

17. - E4B01

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

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

18. - E4C11

Why can an attenuator be used to reduce receiver overload on the lower frequency HF bands with little or no impact on signal-to-noise ratio?

Select	Answer
A	Atmospheric noise is generally greater than internally generated noise even after attenuation
B	Signals are attenuated separately from the noise
C	The attenuator has a low-pass filter to increase the strength of lower frequency signals
D	The attenuator has a noise filter to suppress interference

19. - E4D09

What is the purpose of the preselector in a communications receiver?

Select	Answer
A	To store often-used frequencies
B	To allow selection of the optimum RF amplifier device
C	To provide a range of AGC time constants
D	To increase rejection of signals outside the desired band

20. - E4E08

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

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

21. - E5A13

What is an effect of increasing Q in a series resonant circuit?

Select	Answer
A	Internal voltages increase
B	Phase shift can become uncontrolled
C	Parasitic effects are minimized
D	Fewer components are needed for the same performance

22. - E5B02

What letter is commonly used to represent susceptance?

Select	Answer
A	G
B	Y
C	B
D	X

23. - E5C02

How are impedances described in polar coordinates?

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

24. - E5D06

In what direction is the magnetic field oriented about a conductor in relation to the direction of electron flow?

Select	Answer
A	In a direction opposite to the current
B	In all directions; omni-directional
C	In the same direction as the current
D	In a circle around the conductor

25. - E6A01

In what application is gallium arsenide used as a semiconductor material?

Select	Answer
A	In microwave circuits
B	In very low-frequency RF circuits
C	In high-power audio circuits
D	In high-current rectifier circuits

26. - E6B08

Which of the following is a Schottky barrier diode?

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

27. - E6C04

Which of the following is an advantage of BiCMOS logic?

Select	Answer
A	All these choices are correct
B	It has the high input impedance of CMOS and the low output impedance of bipolar transistors
C	Its simplicity results in much less expensive devices than standard CMOS
D	It is immune to electrostatic damage

28. - E6D13

What is the primary cause of inductor self-resonance?

Select	Answer
A	Non-linear core hysteresis
B	Inter-turn capacitance
C	The skin effect
D	Inductive kickback

29. - E6E11

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

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

30. - E6F08

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

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

31. - E7A01

Which circuit is bistable?

Select	Answer
A	A flip-flop
B	An AND gate
C	An OR gate
D	A bipolar amplifier

32. - E7B15

What is one way to prevent thermal runaway in a bipolar transistor amplifier?

Select	Answer
A	Neutralization
B	Use a resistor in series with the emitter
C	All these choices are correct
D	Select transistors with high beta

33. - E7C02

Which of the following is a property of a T-network with series capacitors and a parallel shunt inductor?

Select	Answer
A	It is a notch filter
B	It is a band-pass filter
C	It is a high-pass filter
D	It is a low-pass filter

34. - E7D05

Which of the following types of linear voltage regulator places a constant load on the unregulated voltage source?

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

35. - E7E10

How does a diode envelope detector function?

Select	Answer
A	By mixing signals with noise in the transition region of the diode
B	By sensing the change of reactance in the diode with respect to frequency
C	By breakdown of the Zener voltage
D	By rectification and filtering of RF signals

36. - E7F08

What is the function of decimation?

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

37. - E7G07

What magnitude of voltage gain can be expected from the circuit in Figure E73 when R1 is 10 ohms and RF is 470 ohms?

Select	Answer
A	24
B	94
C	47
D	0.21

38. - E7H14

What is a phase-locked loop circuit?

Select	Answer
A	An electronic servo loop consisting of a phase detector, a low-pass filter, a voltage-controlled oscillator, and a stable reference oscillator
B	An electronic servo loop consisting of a ratio detector, reactance modulator, and voltage-controlled oscillator
C	An electronic circuit consisting of a precision push-pull amplifier with a differential input
D	An electronic circuit also known as a monostable multivibrator

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	Fourier analysis
C	Vector analysis
D	Differential 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	60
C	0.6
D	1.67

41. - E8C12

What factors affect the bandwidth of a transmitted CW signal?

Select	Answer
A	Modulation index and output power
B	Keying speed and shape factor (rise and fall time)
C	IF bandwidth and Q
D	All these choices are correct

42. - E8D11

What is one advantage of using ASCII code for data communications?

Select	Answer
A	It contains fewer information bits per character than any other code
B	It includes built-in error correction features
C	It is possible to transmit both upper and lower case text
D	It uses one character as a shift code to send numeric and special characters

43. - E9A05

What is included in the total resistance of an antenna system?

Select	Answer
A	Transmission-line resistance plus radiation resistance
B	Radiation resistance plus transmission resistance
C	Radiation resistance plus loss resistance
D	Radiation resistance plus space impedance

44. - E9B04

What is the front-to-back ratio of the radiation pattern shown in Figure E92?

Select	Answer
A	3 dB
B	38 dB
C	28 dB
D	15 dB

45. - E9C03

What is the radiation pattern of two 1/4-wavelength vertical antennas spaced 1/2-wavelength apart and fed in phase?

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

46. - E9D11

Which of the following conductors would be best for minimizing losses in a station's RF ground system?

Select	Answer
A	Wide flat copper strap
B	Solid wire
C	Resistive wire, such as spark plug wire
D	Stranded wire

47. - E9E04

What is the purpose of the series capacitor in a gamma-type antenna matching network?

Select	Answer
A	To provide DC isolation between the feed line and the antenna
B	To cancel the inductive reactance of the matching network
C	To transform the antenna impedance to a higher value
D	To provide a rejection notch that prevents the radiation of harmonics

48. - E9F04

What impedance does a 1/2-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	Very low impedance
C	The same as the output impedance of the generator
D	Very high impedance

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. - E9H09

What is a Pennant antenna?

Select	Answer
A	A four-element, high-gain vertical array invented by George Pennant
B	A form of rhombic antenna terminated in a variable capacitor to provide frequency diversity
C	A stealth antenna built to look like a flagpole
D	A small, vertically oriented receiving antenna consisting of a triangular loop terminated in approximately 900 ohms