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

2. - E1A13

Who must be in physical control of the station apparatus of an amateur station aboard any vessel or craft that is documented or registered in the United States?

Select	Answer
A	Any person named in an amateur station license grant or a person holding an unrestricted Radiotelephone Operator Permit
B	Only a person named in an amateur station license grant
C	Only a person with an FCC Marine Radio license grant
D	Any person holding an FCC issued amateur license or who is authorized for alien reciprocal operation

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	15 kHz
B	3 kHz
C	10 kHz
D	20 kHz

4. - E1C06

Which of the following is required in order to operate in accordance with CEPT rules in foreign countries where permitted?

Select	Answer
A	You must identify in the official language of the country in which you are operating
B	You must append "/CEPT" to your call sign
C	You must bring a copy of FCC Public Notice DA 16-1048
D	The U.S. embassy must approve of your operation

5. - E1D07

Which HF amateur bands have frequencies authorized for space stations?

Select	Answer
A	All HF bands
B	Only the 40, 20, 17, 15, and 10 meter bands
C	Only the 40, 20, 17, 15, 12, and 10 meter bands
D	Only the 40, 30, 20, 15, 12, and 10 meter bands

6. - E1E02

Who does Part 97 task with maintaining the pools of questions for all U.S. amateur license examinations?

Select	Answer
A	The ARRL
B	The VEs
C	The FCC
D	The VECs

7. - E1F04

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

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

8. - E2A10

What type of satellite appears to stay in one position in the sky?

Select	Answer
A	Geomagnetic
B	LEO
C	Geostationary
D	HEO

9. - E2B07

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

Select	Answer
A	Hue
B	Luminance
C	Chroma
D	Spectral intensity

10. - E2C09

What type of equipment is commonly used to implement an amateur radio mesh network?

Select	Answer
A	An optical cable connection between the USB ports of 2 separate computers
B	A 440 MHz transceiver with a 9600 baud modem
C	A 2 meter VHF transceiver with a 1200 baud modem
D	A wireless router running custom firmware

11. - E2D02

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

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

12. - E2E02

What do the letters FEC mean as they relate to digital operation?

Select	Answer
A	Forward Error Correction
B	First Error Correction
C	Final Error Correction
D	Fatal Error Correction

13. - E3A03

When scheduling EME contacts, which of these conditions will generally result in the least path loss?

Select	Answer
A	When the moon is at apogee
B	When the moon is full
C	When the moon is at perigee
D	When the MUF is above 30 MHz

14. - E3B03

What is the best time of day for transequatorial propagation?

Select	Answer
A	Afternoon or early evening
B	Morning
C	Noon
D	Late at night

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	Eastward
B	Westward
C	Northward
D	Southward

16. - E4A05

What is the purpose of the prescaler function on a frequency counter?

Select	Answer
A	It amplifies low-level signals for more accurate counting
B	It prevents oscillation in a low-frequency counter circuit
C	It divides a higher frequency signal so a low-frequency counter can display the input frequency
D	It multiplies a higher frequency signal so a low-frequency counter can display the operating frequency

17. - E4B11

Which of the following can be measured with a vector network analyzer?

Select	Answer
A	All these choices are correct
B	Input impedance
C	Reflection coefficient
D	Output impedance

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. - E4D07

Which of the following reduces the likelihood of receiver desensitization?

Select	Answer
A	Decrease the RF bandwidth of the receiver
B	Raise the receiver IF frequency
C	Increase the receiver front end gain
D	Switch from fast AGC to slow AGC

20. - E4E07

Which of the following can cause shielded cables to radiate or receive interference?

Select	Answer
A	Use of braided shielding material
B	Tying all ground connections to a common point resulting in differential-mode currents in the shield
C	Common-mode currents on the shield and conductors
D	Low inductance ground connections at both ends of the shield

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	Fewer components are needed for the same performance
D	Parasitic effects are minimized

22. - E5B04

What is the time constant of a circuit having two 220-microfarad capacitors and two 1-megohm resistors, all in parallel?

Select	Answer
A	220 seconds
B	55 seconds
C	110 seconds
D	440 seconds

23. - E5C03

Which of the following represents an inductive reactance in polar coordinates?

Select	Answer
A	A positive magnitude
B	A positive phase angle
C	A negative magnitude
D	A negative phase angle

24. - E5D13

How many watts are consumed in a circuit consisting of a 100-ohm resistor in series with a 100-ohm inductive reactance drawing 1 ampere?

Select	Answer
A	70.7 watts
B	100 watts
C	141.4 watts
D	200 watts

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	Alpha cutoff frequency
C	Corner frequency
D	Beta cutoff frequency

26. - E6B08

Which of the following is a Schottky barrier diode?

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

27. - E6C09

What is a Programmable Logic Device (PLD)?

Select	Answer
A	A logic circuit that can be modified during use
B	A programmable collection of logic gates and circuits in a single integrated circuit
C	Programmable equipment used for testing digital logic integrated circuits
D	A type of transistor whose gain can be changed by digital logic circuits

28. - E6D04

Which materials are commonly used as a core in an inductor?

Select	Answer
A	Cobalt and aluminum
B	Teflon and Delrin
C	Ferrite and brass
D	Polystyrene and polyethylene

29. - E6E04

Which is the most common input and output impedance of circuits that use MMICs?

Select	Answer
A	10 ohms
B	50 ohms
C	300 ohms
D	450 ohms

30. - E6F11

What is the approximate open-circuit voltage produced by a fully illuminated silicon photovoltaic cell?

Select	Answer
A	0.1 V
B	12 V
C	0.5 V
D	1.5 V

31. - E7A02

What is the function of a decade counter?

Select	Answer
A	It decodes a binary number for display on a seven-segment LED display
B	It produces 10 output pulses for every input pulse
C	It produces one output pulse for every 10 input pulses
D	It decodes a decimal number for display on a seven-segment LED display

32. - E7B18

What is a characteristic of a grounded-grid amplifier?

Select	Answer
A	High filament voltage
B	High power gain
C	Low bandwidth
D	Low input impedance

33. - E7C03

What advantage does a series-L Pi-L-network have over a series-L Pi-network for impedance matching between the final amplifier of a vacuum-tube transmitter and an antenna?

Select	Answer
A	Does not require a capacitor
B	Greater harmonic suppression
C	Higher efficiency
D	Greater transformation range

34. - E7D15

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

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

35. - E7E09

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

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

36. - E7F04

What is a common method of generating an SSB signal using digital signal processing?

Select	Answer
A	Mixing products are converted to voltages and subtracted by adder circuits
B	Signals are combined in quadrature phase relationship
C	A frequency synthesizer removes the unwanted sidebands
D	Varying quartz crystal characteristics emulated in digital form

37. - E7G05

How can unwanted ringing and audio instability be prevented in an op-amp RC audio filter circuit?

Select	Answer
A	Restrict both gain and Q
B	Increase both gain and Q
C	Restrict gain but increase Q
D	Restrict Q but increase gain

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 circuit consisting of a precision push-pull amplifier with a differential input
C	An electronic servo loop consisting of a ratio detector, reactance modulator, and voltage-controlled oscillator
D	An electronic circuit also known as a monostable multivibrator

39. - E8A04

What is "dither" with respect to analog-to-digital converters?

Select	Answer
A	A small amount of noise added to the input signal to allow more precise representation of a signal over time
B	A method of decimation by randomly skipping samples
C	An abnormal condition where the converter cannot settle on a value to represent the signal
D	An error caused by irregular quantization step size

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	0.47
B	47
C	2.14
D	0.214

41. - E8C07

What is the bandwidth of a 4800-Hz frequency shift, 9600-baud ASCII FM transmission?

Select	Answer
A	9.6 kHz
B	5.76 kHz
C	4.8 kHz
D	15.36 kHz

42. - E8D10

What are some of the differences between the Baudot digital code and ASCII?

Select	Answer
A	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
B	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
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 7 data bits per character, ASCII uses 8; Baudot has no letters/figures shift code, ASCII uses 2 letters/figures shift codes

43. - E9A01

What is an isotropic antenna?

Select	Answer
A	A theoretical, omnidirectional antenna used as a reference for antenna gain
B	A spacecraft antenna used to direct signals toward Earth
C	A grounded antenna used to measure Earth conductivity
D	A horizontally polarized antenna used to compare Yagi antennas

44. - E9B10

What is the principle of a Method of Moments analysis?

Select	Answer
A	A wire is modeled as a single sine-wave current generator
B	A wire is modeled as a series of segments, each having a uniform value of current
C	A wire is modeled as a single sine-wave voltage source
D	A wire is modeled as a series of segments, each having a distinct value of voltage across it

45. - E9C12

Which of the following describes an Extended Double Zepp antenna?

Select	Answer
A	A center-fed 1.25-wavelength antenna (two 5/8-wave elements in phase)
B	A portable antenna erected using two push support poles
C	An end-fed folded dipole antenna
D	A wideband vertical antenna constructed from precisely tapered aluminum tubing

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 a metal water pipe
D	An electrically short connection to 3 or 4 interconnected ground rods via a series RF choke

47. - E9E09

Which of the following is used to shunt-feed a grounded tower at its base?

Select	Answer
A	All these choices are correct
B	Gamma match
C	Double-bazooka match
D	Hairpin 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 center conductor resistivity
C	Dielectric materials used in the line
D	The termination impedance

49. - E9G11

How are the wavelength scales on a Smith chart calibrated?

Select	Answer
A	In fractions of transmission line electrical frequency
B	In fractions of transmission line electrical wavelength
C	In fractions of antenna electrical wavelength
D	In fractions of antenna electrical frequency

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