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

2. - E1A02

When using a transceiver that displays the carrier frequency of phone signals, which of the following displayed frequencies represents the lowest frequency at which a properly adjusted LSB emission will be totally within the band?

Select	Answer
A	300 Hz above the lower band edge
B	3 kHz above the lower band edge
C	The exact lower band edge
D	1 kHz above the lower band edge

3. - E1B02

Which of the following is an acceptable bandwidth for Digital Radio Mondiale (DRM) based voice or SSTV digital transmissions made on the HF amateur bands?

Select	Answer
A	3 kHz
B	10 kHz
C	20 kHz
D	15 kHz

4. - E1C02

Which of the following types of communications may be transmitted to amateur stations in foreign countries?

Select	Answer
A	Communications incidental to the purpose of the amateur service and remarks of a personal nature
B	All these choices are correct
C	Messages intended for users of the maritime satellite service
D	Business-related messages for non-profit organizations

5. - E1D11

Which amateur stations are eligible to operate as Earth stations?

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

6. - E1E05

What is the minimum passing score on all amateur operator license examinations?

Select	Answer
A	Minimum passing score of 80%
B	Minimum passing score of 77%
C	Minimum passing score of 70%
D	Minimum passing score of 74%

7. - E1F07

When may an amateur station send a message to a business?

Select	Answer
A	When neither the amateur nor his or her employer has a pecuniary interest in the communications
B	When the total money involved does not exceed $25
C	When transmitting international third-party communications
D	When the control operator is employed by the FCC or another government agency

8. - E2A08

Why should effective radiated power to a satellite that uses a linear transponder be limited?

Select	Answer
A	To prevent creating errors in the satellite telemetry
B	To avoid interfering with terrestrial QSOs
C	To avoid reducing the downlink power to all other users
D	To prevent the satellite from emitting out-of-band signals

9. - E2B09

What hardware, other than a receiver with SSB capability and a suitable computer, is needed to decode SSTV using Digital Radio Mondiale (DRM)?

Select	Answer
A	No other hardware is needed
B	A special IF converter
C	A special notch filter to remove synchronization pulses
D	A special front end limiter

10. - E2C04

Which of the following frequencies are sometimes used for amateur radio mesh networks?

Select	Answer
A	Frequencies shared with various unlicensed wireless data services
B	HF frequencies where digital communications are permitted
C	The 60 meter band channel centered on 5373 kHz
D	Cable TV channels 41 through 43

11. - E2D01

Which of the following digital modes is designed for meteor scatter communications?

Select	Answer
A	MSK144
B	Hellschreiber
C	APRS
D	WSPR

12. - E2E06

What is the most common data rate used for HF packet?

Select	Answer
A	110 baud
B	1200 baud
C	48 baud
D	300 baud

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. - E3B10

Why is chordal hop propagation desirable?

Select	Answer
A	The signal experiences less loss compared to multi-hop using Earth as a reflector
B	Atmospheric noise is lower in the direction of chordal hop propagation
C	The MUF for chordal hop propagation is much lower than for normal skip propagation
D	Signals travel faster along ionospheric chords

15. - E3C15

What might be indicated by a sudden rise in radio background noise across a large portion of the HF spectrum?

Select	Answer
A	A temperature inversion has occurred
B	Increased transequatorial propagation is likely
C	Long-path propagation is likely
D	A solar flare has occurred

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	Sampling rate of the analog-to-digital converter
C	Amount of memory
D	Q of the circuit

17. - E4B08

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

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

18. - E4C08

An SDR receiver is overloaded when input signals exceed what level?

Select	Answer
A	The maximum count value of the analog-to-digital converter
B	One-half the maximum sample rate
C	One-half the maximum sampling buffer size
D	The reference voltage of the analog-to-digital converter

19. - E4D06

What is the term for spurious signals generated by the combination of two or more signals in a non-linear device or circuit?

Select	Answer
A	Intermodulation
B	Adjacent channel interference
C	Neutralization
D	Amplifier desensitization

20. - E4E02

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

Select	Answer
A	Broadband white noise
B	All these choices are correct
C	Power line noise
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	157.8 Hz
B	47.3 kHz
C	23.67 kHz
D	315.6 Hz

22. - E5B11

What is the phase angle between the voltage across and the current through a series RLC circuit if XC is 25 ohms, R is 100 ohms, and XL is 50 ohms?

Select	Answer
A	76 degrees with the voltage leading the current
B	76 degrees with the voltage lagging the current
C	14 degrees with the voltage lagging the current
D	14 degrees with the voltage leading the current

23. - E5C11

Which point in Figure E5-1 best represents the impedance of a series circuit consisting of a 300-ohm resistor and an 18-microhenry inductor at 3.505 MHz?

Select	Answer
A	Point 1
B	Point 3
C	Point 8
D	Point 7

24. - E5D03

What is microstrip?

Select	Answer
A	Lightweight transmission line made of common zip cord
B	Short lengths of coax mounted on printed circuit boards to minimize time delay between microwave circuits
C	Miniature coax used for low power applications
D	Precision printed circuit conductors above a ground plane that provide constant impedance interconnects at microwave frequencies

25. - E6A08

What term indicates the frequency at which the grounded-base current gain of a transistor has decreased to 0.7 of the gain obtainable at 1 kHz?

Select	Answer
A	Alpha rejection frequency
B	Corner frequency
C	Beta cutoff frequency
D	Alpha cutoff frequency

26. - E6B01

What is the most useful characteristic of a Zener diode?

Select	Answer
A	A negative resistance region
B	An internal capacitance that varies with the applied voltage
C	A constant current drop under conditions of varying voltage
D	A constant voltage drop under conditions of varying current

27. - E6C05

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

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

28. - E6D07

What is current in the primary winding of a transformer called if no load is attached to the secondary?

Select	Answer
A	Excitation current
B	Stabilizing current
C	Direct current
D	Magnetizing current

29. - E6E05

Which of the following noise figure values is typical of a low-noise UHF preamplifier?

Select	Answer
A	-10 dB
B	2 dB
C	-20 dBm
D	44 dBm

30. - E6F06

Which of these materials is most commonly used to create photoconductive devices?

Select	Answer
A	An ordinary metal
B	A heavy metal
C	A crystalline semiconductor
D	A liquid semiconductor

31. - E7A07

What logical operation does a NAND gate perform?

Select	Answer
A	It produces logic 1 at its output only when all inputs are logic 1
B	It produces logic 0 at its output only when all inputs are logic 1
C	It produces logic 0 at its output if some but not all inputs are logic 1
D	It produces logic 0 at its output only when all inputs are logic 0

32. - E7B14

Why are switching amplifiers more efficient than linear amplifiers?

Select	Answer
A	Switching amplifiers use push-pull circuits
B	Switching amplifiers operate at higher voltages
C	Linear amplifiers have high gain resulting in higher harmonic content
D	The power transistor is at saturation or cutoff most of the time

33. - E7C05

Which filter type is described as having ripple in the passband and a sharp cutoff?

Select	Answer
A	A passive op-amp filter
B	A Butterworth filter
C	An active LC filter
D	A Chebyshev 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 shunt current source
C	A shunt regulator
D	A series regulator

35. - E7E08

What are the principal frequencies that appear at the output of a mixer circuit?

Select	Answer
A	Two and four times the original frequency
B	1.414 and 0.707 times the input frequency
C	The two input frequencies along with their sum and difference frequencies
D	The square root of the product of input frequencies

36. - E7F13

What is the function of taps in a digital signal processing filter?

Select	Answer
A	Select the point at which baseband signals are generated
B	Provide access for debugging software
C	To reduce excess signal pressure levels
D	Provide incremental signal delays for filter algorithms

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	0.21
B	94
C	47
D	24

38. - E7H15

Which of these functions can be performed by a phase-locked loop?

Select	Answer
A	Wide-band AF and RF power amplification
B	Frequency synthesis, FM demodulation
C	Comparison of two digital input signals, digital pulse counter
D	Photovoltaic conversion, optical coupling

39. - E8A03

What type of wave does a Fourier analysis show to be made up of sine waves of a given fundamental frequency plus all its harmonics?

Select	Answer
A	A sine wave
B	A cosine wave
C	A square wave
D	A sawtooth wave

40. - E8B02

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

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

41. - E8C12

What factors affect the bandwidth of a transmitted CW signal?

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

42. - E8D08

What parameter evaluates distortion of an AFSK signal caused by excessive input audio levels?

Select	Answer
A	Baud rate
B	Intermodulation Distortion (IMD)
C	Repeat Request Rate (RRR)
D	Signal-to-noise ratio

43. - E9A09

What is antenna efficiency?

Select	Answer
A	Radiation resistance divided by total resistance
B	Effective radiated power divided by transmitter output
C	Total resistance divided by radiation resistance
D	Radiation resistance divided by transmission resistance

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

45. - E9C07

What is the approximate feed point impedance at the center of a two-wire folded dipole antenna?

Select	Answer
A	72 ohms
B	450 ohms
C	300 ohms
D	50 ohms

46. - E9D12

Which of the following would provide the best RF ground for your station?

Select	Answer
A	A 50-ohm resistor connected to ground
B	An electrically short connection to 3 or 4 interconnected ground rods driven into the Earth
C	An electrically short connection to 3 or 4 interconnected ground rods via a series RF choke
D	An electrically short connection to a metal water pipe

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	50 ohms
B	62 ohms
C	75 ohms
D	450 ohms

48. - E9F08

Which of the following is a significant difference between foam dielectric coaxial cable and solid dielectric cable, assuming all other parameters are the same?

Select	Answer
A	Foam dielectric has higher velocity factor
B	All these choices are correct
C	Foam dielectric has lower safe operating voltage limits
D	Foam dielectric has lower loss per unit of length

49. - E9G03

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

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

50. - E9H07

Why is RF attenuation used when direction-finding?

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

Figure E5-1