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

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1. - E0A10

What toxic material may be present in some electronic components such as high voltage capacitors and transformers?

Select	Answer
A	Polychlorinated biphenyls
B	Polymorphic silicon
C	Polytetrafluoroethylene
D	Polyethylene

2. - E1A01

Which of the following carrier frequencies is illegal for LSB AFSK emissions on the 17 meter band RTTY and data segment of 18.068 to 18.110 MHz?

Select	Answer
A	18.110 MHz
B	18.068 MHz
C	18.100 MHz
D	18.107 MHz

3. - E1B01

Which of the following constitutes a spurious emission?

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

4. - E1C07

At what level below a signal's mean power level is its bandwidth determined according to FCC rules?

Select	Answer
A	6 dB
B	23 dB
C	26 dB
D	3 dB

5. - E1D01

What is the definition of telemetry?

Select	Answer
A	One-way transmission of measurements at a distance from the measuring instrument
B	Two-way transmissions in excess of 1000 feet
C	Two-way transmissions of data
D	One-way transmission that initiates, modifies, or terminates the functions of a device at a distance

6. - E1E09

What may be the penalty for a VE who fraudulently administers or certifies an examination?

Select	Answer
A	A fine of up to $1000 per occurrence
B	All these choices are correct
C	A sentence of up to one year in prison
D	Revocation of the VE's amateur station license grant and the suspension of the VE's amateur operator license grant

7. - E1F04

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

Select	Answer
A	A line roughly parallel to and west of the U.S. Atlantic coastline
B	A line roughly parallel to and south of the border between the U.S. and Canada
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. - E2A04

What is meant by the term mode? as applied to an amateur radio satellite?

Select	Answer
A	Whether the satellite is in a low earth or geostationary orbit
B	The satellite's uplink and downlink frequency bands
C	The satellite's orientation with respect to the Earth
D	Whether the satellite is in a polar or equatorial orbit

9. - E2B08

What technique allows commercial analog TV receivers to be used for fast-scan TV operations on the 70 cm band?

Select	Answer
A	Transmitting on channels shared with cable TV
B	Transmitting on the abandoned TV channel 2
C	Using USB and demodulating the signal with a computer sound card
D	Using converted satellite TV dishes

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	Discovery and link establishment protocols
C	Forward error correction and Viterbi codes
D	Acting as store-and-forward digipeaters

11. - E2D02

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

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

13. - E3A12

What is the cause of auroral activity?

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

14. - E3B01

What is transequatorial propagation?

Select	Answer
A	Propagation between a point on the equator and its antipodal point
B	Propagation between points located on the magnetic equator
C	Propagation between two mid-latitude points at approximately the same distance north and south of the magnetic equator
D	Propagation between points at the same latitude

15. - E3C14

Why does the radio-path horizon distance exceed the geometric horizon?

Select	Answer
A	D-region skip
B	Due to the Doppler effect
C	Downward bending due to density variations in the atmosphere
D	E-region skip

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

17. - E4B07

What do the subscripts of S parameters represent?

Select	Answer
A	The relative time between measurements
B	Relative quality of the data
C	Frequency order of the measurements
D	The port or ports at which measurements are made

18. - E4C04

What is the noise figure of a receiver?

Select	Answer
A	The ratio in dB of the noise generated by the receiver to the theoretical minimum noise
B	The ratio of atmospheric noise to phase noise
C	The ratio of thermal noise to atmospheric noise
D	The ratio of the noise bandwidth in hertz to the theoretical bandwidth of a resistive network

19. - E4D04

Which of the following may reduce or eliminate intermodulation interference in a repeater caused by another transmitter operating in close proximity?

Select	Answer
A	A band-pass filter in the feed line between the transmitter and receiver
B	Utilizing a Class D final amplifier
C	Utilizing a Class C final amplifier
D	A properly terminated circulator at the output of the repeater's transmitter

20. - E4E02

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

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

21. - E5A13

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

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

22. - E5B06

What is susceptance?

Select	Answer
A	The ratio of magnetic field to electric field
B	The imaginary part of admittance
C	The magnetic impedance of a circuit
D	A measure of the efficiency of a transformer

23. - E5C04

What coordinate system is often used to display the resistive, inductive, and/or capacitive reactance components of impedance?

Select	Answer
A	Rectangular coordinates
B	Faraday grid
C	Maidenhead grid
D	Elliptical coordinates

24. - E5D01

What is the result of skin effect?

Select	Answer
A	Thermal effects on the surface of the conductor increase the impedance
B	As frequency increases, RF current flows in a thinner layer of the conductor, closer to the surface
C	Thermal effects on the surface of the conductor decrease the impedance
D	As frequency decreases, RF current flows in a thinner layer of the conductor, closer to the surface

25. - E6A02

Which of the following semiconductor materials contains excess free electrons?

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

26. - E6B10

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

Select	Answer
A	1
B	5
C	7
D	6

27. - E6C08

In Figure E6-3, what is the schematic symbol for a NAND gate?

Select	Answer
A	3
B	4
C	1
D	2

28. - E6D05

What is one reason for using ferrite cores rather than powdered iron in an inductor?

Select	Answer
A	Ferrite toroids generally require fewer turns to produce a given inductance value
B	Ferrite toroids are easier to use with surface mount technology
C	Ferrite toroids generally have lower initial permeability
D	Ferrite toroids generally have better temperature stability

29. - E6E12

Why are DIP through-hole package ICs not typically used at UHF and higher frequencies?

Select	Answer
A	Unsuitable for combining analog and digital signals
B	Too many pins
C	Epoxy coating is conductive above 300 MHz
D	Excessive lead length

30. - E6F09

What is the efficiency of a photovoltaic cell?

Select	Answer
A	Cost per kilowatt-hour generated
B	The output RF power divided by the input DC power
C	The open-circuit voltage divided by the short-circuit current under full illumination
D	The relative fraction of light that is converted to current

31. - E7A10

What is a truth table?

Select	Answer
A	A table of logic symbols that indicate the high logic states of an op-amp
B	A list of inputs and corresponding outputs for a digital device
C	A table of logic symbols that indicate the logic states of an op-amp
D	A diagram showing logic states when the digital device output is true

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. - 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 high-pass filter
B	It is a low-pass filter
C	It is a band-pass filter
D	It is a notch filter

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. - E7E03

What is a frequency discriminator stage in a FM receiver?

Select	Answer
A	A circuit for detecting FM signals
B	An FM generator circuit
C	A circuit for filtering two closely adjacent signals
D	An automatic band-switching circuit

36. - E7F12

Which of the following is an advantage of a Finite Impulse Response (FIR) filter vs an Infinite Impulse Response (IIR) digital filter?

Select	Answer
A	FIR filters can respond faster to impulses
B	All these choices are correct
C	FIR filters are easier to implement for a given set of passband rolloff requirements
D	FIR filters can delay all frequency components of the signal by the same amount

37. - E7G08

How does the gain of an ideal operational amplifier vary with frequency?

Select	Answer
A	It decreases logarithmically with increasing frequency
B	It does not vary with frequency
C	It increases linearly with increasing frequency
D	It decreases linearly with increasing frequency

38. - E7H09

What type of frequency synthesizer circuit uses a phase accumulator, lookup table, digital to analog converter, and a low-pass anti-alias filter?

Select	Answer
A	A phase-locked loop synthesizer
B	A direct digital synthesizer
C	A hybrid synthesizer
D	A diode-switching matrix synthesizer

39. - E8A08

Why would a direct or flash conversion analog-to-digital converter be useful for a software defined radio?

Select	Answer
A	Very low power consumption decreases frequency drift
B	Very high speed allows digitizing high frequencies
C	Immunity to out-of-sequence coding reduces spurious responses
D	All these choices are correct

40. - E8B10

What is frequency division multiplexing?

Select	Answer
A	The transmitted signal is divided into packets of information
B	Two or more information streams are merged into a digital combiner, which then pulse position modulates the transmitter
C	Two or more information streams are merged into a baseband, which then modulates the transmitter
D	The transmitted signal jumps from band to band at a predetermined rate

41. - E8C01

How is Forward Error Correction implemented?

Select	Answer
A	By varying the frequency shift of the transmitted signal according to a predefined algorithm
B	By the receiving station repeating each block of three data characters
C	By transmitting a special algorithm to the receiving station along with the data characters
D	By transmitting extra data that may be used to detect and correct transmission errors

42. - E8D06

What is the advantage of including parity bits in ASCII characters?

Select	Answer
A	Faster transmission rate
B	The signal can overpower interfering signals
C	Foreign language characters can be sent
D	Some types of errors can be detected

43. - E9A05

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

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

44. - E9B02

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

Select	Answer
A	24 dB
B	36 dB
C	14 dB
D	18 dB

45. - E9C08

What is a folded dipole antenna?

Select	Answer
A	A type of ground-plane antenna
B	A dipole configured to provide forward gain
C	A half-wave dipole with an additional parallel wire connecting its two ends
D	A dipole one-quarter wavelength long

46. - E9D01

How much does the gain of an ideal parabolic dish antenna change when the operating frequency is doubled?

Select	Answer
A	2 dB
B	4 dB
C	6 dB
D	3 dB

47. - E9E06

Which of these feed line impedances would be suitable for constructing a quarter-wave Q-section for matching a 100-ohm loop to 50-ohm feed line?

Select	Answer
A	75 ohms
B	450 ohms
C	50 ohms
D	62 ohms

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

49. - E9G01

Which of the following can be calculated using a Smith chart?

Select	Answer
A	Radiation resistance
B	Radio propagation
C	Antenna radiation pattern
D	Impedance along transmission lines

50. - E9H07

Why is RF attenuation used when direction-finding?

Select	Answer
A	To prevent receiver overload which reduces pattern nulls
B	To narrow the receiver bandwidth
C	To increase receiver sensitivity
D	To compensate for isotropic directivity and the antenna effect of feed lines

Figure E6-2

Figure E6-3

Figure E9-1