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

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1. - E0A07

How may dangerous levels of carbon monoxide from an emergency generator be detected?

Select	Answer
A	By the odor
B	Only with a carbon monoxide detector
C	By the yellowish appearance of the gas
D	Any ordinary smoke detector can be used

2. - E1A03

What is the maximum legal carrier frequency on the 20 meter band for transmitting USB AFSK digital signals having a 1 kHz bandwidth?

Select	Answer
A	14.070 MHz
B	14.149 MHz
C	14.349 MHz
D	14.100 MHz

3. - E1B05

What is the National Radio Quiet Zone?

Select	Answer
A	An area in New Mexico surrounding the White Sands Test Area
B	An area in Puerto Rico surrounding the Arecibo Radio Telescope
C	An area surrounding the National Radio Astronomy Observatory
D	An area in Florida surrounding Cape Canaveral

4. - E1C08

What is the maximum permissible duration of a remotely controlled station's transmissions if its control link malfunctions?

Select	Answer
A	10 minutes
B	5 minutes
C	30 seconds
D	3 minutes

5. - E1D06

What is the maximum permitted transmitter output power when operating a model craft by telecommand?

Select	Answer
A	5 watts
B	1 watt
C	100 watts
D	2 watts

6. - E1E04

Which of the following best describes the Volunteer Examiner accreditation process?

Select	Answer
A	The procedure by which a VEC confirms that the VE applicant meets FCC requirements to serve as an examiner
B	The prospective VE obtains accreditation from the FCC
C	The amateur operator applying must pass a VE examination administered by the FCC Enforcement Bureau
D	Each General, Advanced and Amateur Extra Class operator is automatically accredited as a VE when the license is granted

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

8. - E2A07

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

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

9. - E2B07

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

Select	Answer
A	Spectral intensity
B	Chroma
C	Luminance
D	Hue

10. - E2C10

Why might a DX station state that they are listening on another frequency?

Select	Answer
A	All these choices are correct
B	To separate the calling stations from the DX station
C	Because the DX station may be transmitting on a frequency that is prohibited to some responding stations
D	To improve operating efficiency by reducing interference

11. - E2D07

What digital protocol is used by APRS?

Select	Answer
A	AX.25
B	PACTOR
C	802.11
D	AMTOR

12. - E2E06

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

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

13. - E3A06

What might help to restore contact when DX signals become too weak to copy across an entire HF band a few hours after sunset?

Select	Answer
A	Wait 90 minutes or so for the signal degradation to pass
B	Switch to a higher frequency HF band
C	Wait 24 hours before attempting another communication on the band
D	Switch to a lower frequency HF band

14. - E3B04

What is meant by the terms "extraordinary" and "ordinary" waves?

Select	Answer
A	Independent waves created in the ionosphere that are elliptically polarized
B	Extraordinary waves describe rare long-skip propagation compared to ordinary waves, which travel shorter distances
C	Refracted rays and reflected waves
D	Long-path and short-path waves

15. - E3C05

What orientation of Bz (B sub z) increases the likelihood that incoming particles from the sun will cause disturbed conditions?

Select	Answer
A	Northward
B	Southward
C	Eastward
D	Westward

16. - E4A10

Which of the following displays multiple digital signal states simultaneously?

Select	Answer
A	Logic analyzer
B	Network analyzer
C	Bit error rate tester
D	Modulation monitor

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

19. - E4D02

Which of the following describes problems caused by poor dynamic range in a receiver?

Select	Answer
A	Spurious signals caused by cross-modulation and desensitization from strong adjacent signals
B	Cross-modulation of the desired signal and insufficient audio power to operate the speaker
C	Oscillator instability and severe audio distortion of all but the strongest received signals
D	Oscillator instability requiring frequent retuning and loss of ability to recover the opposite sideband

20. - E4E01

What problem can occur when using an automatic notch filter (ANF) to remove interfering carriers while receiving CW signals?

Select	Answer
A	Received CW signals will appear to be modulated at the DSP clock frequency
B	Removal of the CW signal as well as the interfering carrier
C	Ringing in the DSP filter will completely remove the spaces between the CW characters
D	Any nearby signal passing through the DSP system will overwhelm the desired signal

21. - E5A03

What is the magnitude of the impedance of a series RLC circuit at resonance?

Select	Answer
A	Approximately equal to capacitive reactance
B	Approximately equal to circuit resistance
C	High, as compared to the circuit resistance
D	Approximately equal to inductive reactance

22. - E5B09

What is the relationship between the AC current through a capacitor and the voltage across a capacitor?

Select	Answer
A	Current leads voltage by 90 degrees
B	Voltage and current are 180 degrees out of phase
C	Voltage leads current by 90 degrees
D	Voltage and current are in phase

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	Elliptical coordinates
D	Maidenhead grid

24. - E5D03

What is microstrip?

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

25. - E6A02

Which of the following semiconductor materials contains excess free electrons?

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

26. - E6B02

What is an important characteristic of a Schottky diode as compared to an ordinary silicon diode when used as a power supply rectifier?

Select	Answer
A	Longer carrier retention time
B	More constant reverse avalanche voltage
C	Less forward voltage drop
D	Much higher reverse voltage breakdown

27. - E6C02

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

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

28. - E6D03

Which of the following is an aspect of the piezoelectric effect?

Select	Answer
A	Generation of electrical energy in the presence of light
B	Mechanical deformation of material by the application of a magnetic field
C	Increased conductivity in the presence of light
D	Mechanical deformation of material by the application of a voltage

29. - E6E07

What type of transmission line is used for connections to MMICs?

Select	Answer
A	Microstrip
B	Miniature coax
C	Parallel wire
D	Circular waveguide

30. - E6F09

What is the efficiency of a photovoltaic cell?

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

31. - E7A11

What type of logic defines "1" as a high voltage?

Select	Answer
A	Reverse Logic
B	Negative logic
C	Positive Logic
D	Assertive Logic

32. - E7B10

In Figure E7-1, what is the purpose of R1 and R2?

Select	Answer
A	Voltage divider bias
B	Load resistors
C	Feedback
D	Self bias

33. - E7C06

What are the distinguishing features of an elliptical filter?

Select	Answer
A	Extremely sharp cutoff with one or more notches in the stop band
B	Extremely flat response over its pass band with gradually rounded stop band corners
C	Gradual passband rolloff with extreme stop band ripple
D	Gradual passband rolloff with minimal stop band ripple

34. - E7D15

What is the purpose of a step-start circuit in a high-voltage power supply?

Select	Answer
A	To provide a dual-voltage output for reduced power applications
B	To compensate for variations of the incoming line voltage
C	To allow the filter capacitors to charge gradually
D	To allow for remote control of the power supply

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 rectification and filtering of RF signals
D	By breakdown of the Zener voltage

36. - E7F08

What is the function of decimation?

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

37. - E7G03

What is the typical input impedance of an op-amp?

Select	Answer
A	Very high
B	100 ohms
C	1000 ohms
D	Very low

38. - E7H01

What are three oscillator circuits used in amateur radio equipment?

Select	Answer
A	Taft, Pierce and negative feedback
B	Pierce, Fenner and Beane
C	Colpitts, Hartley and Pierce
D	Taft, Hartley and Pierce

39. - E8A02

Which of the following is a type of analog-to-digital conversion?

Select	Answer
A	Phase reversal
B	Level shifting
C	Successive approximation
D	Harmonic regeneration

40. - E8B06

What is the deviation ratio of an FM-phone signal having a maximum frequency swing of plus or minus 7.5 kHz when the maximum modulation frequency is 3.5 kHz?

Select	Answer
A	0.214
B	0.47
C	47
D	2.14

41. - E8C11

What is the relationship between symbol rate and baud?

Select	Answer
A	Baud is twice the symbol rate
B	Symbol rate is only used for packet-based modes
C	Baud is only used for RTTY
D	They are the same

42. - E8D01

Why are received spread spectrum signals resistant to interference?

Select	Answer
A	The high power used by a spread spectrum transmitter keeps its signal from being easily overpowered
B	Signals not using the spread spectrum algorithm are suppressed in the receiver
C	If interference is detected by the receiver it will signal the transmitter to change frequencies
D	The receiver is always equipped with a digital blanker

43. - E9A03

What is the radiation resistance of an antenna?

Select	Answer
A	The specific impedance of the antenna
B	The combined losses of the antenna elements and feed line
C	The value of a resistance that would dissipate the same amount of power as that radiated from an antenna
D	The resistance in the atmosphere that an antenna must overcome to be able to radiate a signal

44. - E9B03

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

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

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

46. - E9D04

Why should an HF mobile antenna loading coil have a high ratio of reactance to resistance?

Select	Answer
A	To swamp out harmonics
B	To minimize the Q
C	To lower the radiation angle
D	To minimize losses

47. - E9E02

What is the name of an antenna matching system that matches an unbalanced feed line to an antenna by feeding the driven element both at the center of the element and at a fraction of a wavelength to one side of center?

Select	Answer
A	The stub match
B	The delta match
C	The epsilon match
D	The gamma match

48. - E9F02

Which of the following has the biggest effect on the velocity factor of a transmission line?

Select	Answer
A	The line length
B	The termination impedance
C	The center conductor resistivity
D	Dielectric materials used in the line

49. - E9G08

What is the process of normalization with regard to a Smith chart?

Select	Answer
A	Reassigning reactance values with regard to the resistance axis
B	Reassigning impedance values with regard to the prime center
C	Reassigning prime center with regard to the reactance axis
D	Reassigning resistance values with regard to the reactance axis

50. - E9H03

What is Receiving Directivity Factor (RDF)?

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

Figure E7-1

Figure E9-1