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

2. - E1A14

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

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

3. - E1B01

Which of the following constitutes a spurious emission?

Select	Answer
A	Any transmitted signal that unintentionally interferes with another licensed radio station
B	An emission outside the signal's necessary bandwidth that can be reduced or eliminated without affecting the information transmitted
C	A signal transmitted to prevent its detection by any station other than the intended recipient
D	An amateur station transmission made without the proper call sign identification

4. - E1C05

When may an automatically controlled station originate third party communications?

Select	Answer
A	Only when transmitting RTTY or data emissions
B	When approved by the National Telecommunication and Information Administration
C	When agreed upon by the sending or receiving station
D	Never

5. - E1D08

Which VHF amateur bands have frequencies authorized for space stations?

Select	Answer
A	6 meters, 2 meters, and 1.25 meters
B	6 meters and 2 meters
C	2 meters and 1.25 meters
D	2 meters

6. - E1E10

What must the administering VEs do after the administration of a successful examination for an amateur operator license?

Select	Answer
A	They must submit the application document to the coordinating VEC according to the coordinating VEC instructions
B	They must collect and send the documents to the NCVEC for grading
C	They must collect and submit the documents to the coordinating VEC for grading
D	They must collect and send the documents to the FCC according to instructions

7. - E1F04

Which of the following geographic descriptions approximately describes "Line A"?

Select	Answer
A	A line roughly parallel to and south of the border between the U.S. and Canada
B	A line roughly parallel to and west of the U.S. Atlantic coastline
C	A line roughly parallel to and north of the border between the U.S. and Mexico
D	A line roughly parallel to and east of the U.S. Pacific coastline

8. - E2A13

Which of the following techniques is normally used by low Earth orbiting digital satellites to relay messages around the world?

Select	Answer
A	Digipeating
B	Multi-satellite relaying
C	Store-and-forward
D	Node hopping

9. - E2B07

What is the name of the signal component that carries color information in NTSC video?

Select	Answer
A	Chroma
B	Luminance
C	Hue
D	Spectral intensity

10. - E2C12

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

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

11. - E2D02

Which of the following is a good technique for making meteor scatter contacts?

Select	Answer
A	Use of special digital modes
B	15-second timed transmission sequences with stations alternating based on location
C	Short transmissions with rapidly repeated call signs and signal reports
D	All these choices are correct

12. - E2E05

Which of these digital modes does not support keyboard-to-keyboard operation?

Select	Answer
A	PSK31
B	PACTOR
C	RTTY
D	MFSK

13. - E3A02

What characterizes libration fading of an EME signal?

Select	Answer
A	A fluttery irregular fading
B	A gradual loss of signal as the sun rises
C	The returning echo is several hertz lower in frequency than the transmitted signal
D	A slow change in the pitch of the CW signal

14. - E3B06

Which of the following amateur bands most frequently provides long-path propagation?

Select	Answer
A	10 meters
B	20 meters
C	6 meters
D	80 meters

15. - E3C12

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

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

16. - E4A08

Which of the following measures SWR?

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

17. - E4B04

Which S parameter represents input port return loss or reflection coefficient (equivalent to VSWR)?

Select	Answer
A	S11
B	S22
C	S21
D	S12

18. - E4C07

What does the MDS of a receiver represent?

Select	Answer
A	The meter display sensitivity
B	The minimum discernible signal
C	The maximum detectable spectrum
D	The multiplex distortion stability

19. - E4D09

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

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

20. - E4E02

Which of the following types of noise can often be reduced with a digital signal processing noise filter?

Select	Answer
A	Power line noise
B	Broadband white noise
C	All these choices are correct
D	Ignition noise

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	315.6 Hz
B	157.8 Hz
C	23.67 kHz
D	47.3 kHz

22. - E5B03

How is impedance in polar form converted to an equivalent admittance?

Select	Answer
A	Take the square root of the magnitude and add 180 degrees to the angle
B	Take the reciprocal of the angle and change the sign of the magnitude
C	Square the magnitude and subtract 90 degrees from the angle
D	Take the reciprocal of the magnitude and change the sign of the angle

23. - E5C09

When using rectangular coordinates to graph the impedance of a circuit, what do the axes represent?

Select	Answer
A	The X axis represents the reactive component and the Y axis represents the resistive component
B	The X axis represents the resistive component and the Y axis represents the reactive component
C	The X axis represents the phase angle and the Y axis represents the magnitude
D	The X axis represents the magnitude and the Y axis represents the phase angle

24. - E5D07

How many watts are consumed in a circuit having a power factor of 0.71 if the apparent power is 500VA?

Select	Answer
A	1.42 mW
B	704 W
C	252 W
D	355 W

25. - E6A03

Why does a PN-junction diode not conduct current when reverse biased?

Select	Answer
A	Only P-type semiconductor material can conduct current
B	Only N-type semiconductor material can conduct current
C	Excess holes in P-type material combine with the electrons in N-type material, converting the entire diode into an insulator
D	Holes in P-type material and electrons in the N-type material are separated by the applied voltage, widening the depletion region

26. - E6B10

In Figure E6-2, what is the schematic symbol for a light-emitting diode?

Select	Answer
A	7
B	6
C	1
D	5

27. - E6C05

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

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

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	Electrolytic capacitors
B	Butterworth filters
C	Steel-core toroids
D	Ferrite beads

29. - E6E01

Why is gallium arsenide (GaAs) useful for semiconductor devices operating at UHF and higher frequencies?

Select	Answer
A	Lower junction voltage drop
B	Higher electron mobility
C	Lower transconductance
D	Higher noise figures

30. - E6F04

What is the photovoltaic effect?

Select	Answer
A	The conversion of voltage to current when exposed to light
B	The conversion of electrical energy to mechanical energy
C	The conversion of light to electrical energy
D	The tendency of a battery to discharge when exposed to light

31. - E7A04

How many flip-flops are required to divide a signal frequency by 4?

Select	Answer
A	4
B	2
C	1
D	8

32. - E7B08

How can an RF power amplifier be neutralized?

Select	Answer
A	By feeding a 180-degree out-of-phase portion of the output back to the input
B	By increasing the driving power
C	By feeding an in-phase component of the output back to the input
D	By reducing the driving power

33. - E7C10

Which of the following filters would be the best choice for use in a 2 meter band repeater duplexer?

Select	Answer
A	A crystal filter
B	A DSP filter
C	A cavity filter
D	An L-C 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 constant current source
B	A series regulator
C	A shunt current source
D	A shunt regulator

35. - E7E09

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

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

36. - E7F02

What kind of digital signal processing audio filter is used to remove unwanted noise from a received SSB signal?

Select	Answer
A	An adaptive filter
B	A phase-inverting filter
C	A Hilbert-transform filter
D	A crystal-lattice filter

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	47
B	94
C	0.21
D	24

38. - E7H10

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

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

39. - E8A09

How many different input levels can be encoded by an analog-to-digital converter with 8-bit resolution?

Select	Answer
A	256
B	256 divided by the gain of the input amplifier
C	8 multiplied by the gain of the input amplifier
D	8

40. - E8B02

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

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

41. - E8C05

What is the approximate bandwidth of a 13-WPM International Morse Code transmission?

Select	Answer
A	52 Hz
B	13 Hz
C	104 Hz
D	26 Hz

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 6 data bits per character, ASCII uses 7 or 8; Baudot has no letters/figures shift code, ASCII uses 2 letters/figures shift codes
D	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

43. - E9A08

What is antenna bandwidth?

Select	Answer
A	The frequency range over which an antenna satisfies a performance requirement
B	The angle formed between two imaginary lines drawn through the element ends
C	The angle between the half-power radiation points
D	Antenna length divided by the number of elements

44. - E9B03

In the antenna radiation pattern shown in Figure E9-1, what is the front-to-side ratio?

Select	Answer
A	18 dB
B	24 dB
C	14 dB
D	12 dB

45. - E9C04

What happens to the radiation pattern of an unterminated long wire antenna as the wire length is increased?

Select	Answer
A	The lobes become more perpendicular to the wire
B	The front-to-back ratio decreases
C	The lobes align more in the direction of the wire
D	The vertical angle increases

46. - E9D06

What happens to the SWR bandwidth when one or more loading coils are used to resonate an electrically short antenna?

Select	Answer
A	It is decreased
B	It is increased
C	It is unchanged if the loading coil is located at the feed point
D	It is unchanged if the loading coil is located at a voltage maximum point

47. - E9E11

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

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

48. - E9F03

Why is the physical length of a coaxial cable transmission line shorter than its electrical length?

Select	Answer
A	Electrical signals move more slowly in a coaxial cable than in air
B	The characteristic impedance is higher in a parallel feed line
C	Skin effect is less pronounced in the coaxial cable
D	The surge impedance is higher in a parallel feed line

49. - E9G03

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

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

50. - E9H02

Which is generally true for low band (160 meter and 80 meter) receiving antennas?

Select	Answer
A	Low loss coax transmission line is essential for good performance
B	Atmospheric noise is so high that gain over a dipole is not important
C	They must be erected at least 1/2 wavelength above the ground to attain good directivity
D	All these choices are correct

Figure E6-2

Figure E9-1