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

2. - E1A07

What is the maximum power permitted on the 2200 meter band?

Select	Answer
A	5 watts EIRP (Equivalent isotropic radiated power)
B	1 watt EIRP (Equivalent isotropic radiated power)
C	50 watts PEP
D	100 watts PEP

3. - E1B11

What does PRB-1 require of regulations affecting amateur radio?

Select	Answer
A	No limitations may be placed on antenna size or placement
B	Reasonable accommodations of amateur radio must be made
C	Amateur radio operations must be permitted in any private residence
D	Use of wireless devices in a vehicle is exempt from regulation

4. - E1C04

What is meant by IARP?

Select	Answer
A	An international amateur radio permit that allows U.S. amateurs to operate in certain countries of the Americas
B	An indication of increased antenna reflected power
C	A forecast of intermittent aurora radio propagation
D	The internal amateur radio practices policy of the FCC

5. - E1D01

What is the definition of telemetry?

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

6. - E1E08

To which of the following examinees may a VE not administer an examination?

Select	Answer
A	Employees of the VE
B	Relatives of the VE as listed in the FCC rules
C	Friends of the VE
D	All these choices are correct

7. - E1F10

Who may be the control operator of an auxiliary station?

Select	Answer
A	Only Amateur Extra Class operators
B	Only General, Advanced or Amateur Extra Class operators
C	Only Technician, General, Advanced or Amateur Extra Class operators
D	Any licensed amateur operator

8. - E2A02

Which of the following occurs when a satellite is using an inverting linear transponder?

Select	Answer
A	Doppler shift is reduced because the uplink and downlink shifts are in opposite directions
B	All these choices are correct
C	Upper sideband on the uplink becomes lower sideband on the downlink, and vice versa
D	Signal position in the band is reversed

9. - E2B05

Which of the following describes the use of vestigial sideband in analog fast-scan TV transmissions?

Select	Answer
A	Vestigial sideband reduces bandwidth while allowing for simple video detector circuitry
B	The vestigial sideband carries the audio information
C	Vestigial sideband provides high frequency emphasis to sharpen the picture
D	The vestigial sideband contains chroma information

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

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	All these choices are correct
D	Use of special digital modes

12. - E2E13

Which of these digital modes has the fastest data throughput under clear communication conditions?

Select	Answer
A	AMTOR
B	300 baud packet
C	170 Hz shift, 45 baud RTTY
D	PSK31

13. - E3A03

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

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

14. - E3B09

At what time of year is sporadic E propagation most likely to occur?

Select	Answer
A	Around the equinoxes, especially the spring equinox
B	Around the equinoxes, especially the fall equinox
C	Around the solstices, especially the summer solstice
D	Around the solstices, especially the winter solstice

15. - E3C04

What does the value of Bz (B sub Z) represent?

Select	Answer
A	Duration of long-delayed echoes
B	Direction and strength of the interplanetary magnetic field
C	Geomagnetic field stability
D	Critical frequency for vertical transmissions

16. - E4A09

Which of the following is good practice when using an oscilloscope probe?

Select	Answer
A	Never use a DC-coupled probe to measure an AC circuit
B	Keep the signal ground connection of the probe as short as possible
C	Never use a high-impedance probe to measure a low-impedance circuit
D	All these choices are correct

17. - E4B07

What do the subscripts of S parameters represent?

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

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	The reference voltage of the analog-to-digital converter
C	One-half the maximum sample rate
D	One-half the maximum sampling buffer size

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	Amplifier desensitization
D	Neutralization

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. - E5A07

What is the magnitude of the current at the input of a parallel RLC circuit at resonance?

Select	Answer
A	Maximum
B	Minimum
C	R/L
D	L/R

22. - E5B02

What letter is commonly used to represent susceptance?

Select	Answer
A	Y
B	X
C	B
D	G

23. - E5C03

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

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

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	100 watts
B	70.7 watts
C	141.4 watts
D	200 watts

25. - E6A03

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

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

26. - E6B01

What is the most useful characteristic of a Zener diode?

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

27. - E6C03

What is tri-state logic?

Select	Answer
A	Proprietary logic devices manufactured by Tri-State Devices
B	Logic devices with 0, 1, and high-impedance output states
C	Low-power logic devices designed to operate at 3 volts
D	Logic devices that utilize ternary math

28. - E6D11

Which type of core material decreases inductance when inserted into a coil?

Select	Answer
A	Ferrite
B	Ceramic
C	Brass
D	Powdered iron

29. - E6E07

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

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

30. - E6F09

What is the efficiency of a photovoltaic cell?

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

31. - E7A04

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

Select	Answer
A	4
B	2
C	8
D	1

32. - E7B18

What is a characteristic of a grounded-grid amplifier?

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

33. - E7C12

What is one advantage of a Pi-matching network over an L-matching network consisting of a single inductor and a single capacitor?

Select	Answer
A	Pi-networks are more stable
B	L-networks cannot perform impedance transformation
C	The Q of Pi-networks can be controlled
D	Pi-networks provide balanced input and output

34. - E7D11

What is the function of the pass transistor in a linear voltage regulator circuit?

Select	Answer
A	Maintains nearly constant output impedance over a wide range of load current
B	Maintains nearly constant output voltage over a wide range of load current
C	Provides a stable input impedance over a wide range of source voltage
D	Permits a wide range of output voltage settings

35. - E7E09

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

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

36. - E7F13

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

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

37. - E7G11

What absolute voltage gain can be expected from the circuit in Figure E7-3 when R1 is 3300 ohms and RF is 47 kilohms?

Select	Answer
A	28
B	0.07
C	7
D	14

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

39. - E8A10

What is the purpose of a low-pass filter used in conjunction with a digital-to-analog converter?

Select	Answer
A	All these choices are correct
B	Improve accuracy by removing out-of-sequence codes from the input
C	Lower the input bandwidth to increase the effective resolution
D	Remove harmonics from the output caused by the discrete analog levels generated

40. - E8B05

What is the deviation ratio of an FM-phone signal having a maximum frequency swing of plus-or-minus 5 kHz when the maximum modulation frequency is 3 kHz?

Select	Answer
A	1.67
B	0.6
C	0.167
D	60

41. - E8C04

What technique minimizes the bandwidth of a PSK31 signal?

Select	Answer
A	Zero-sum character encoding
B	Reed-Solomon character encoding
C	Use of sinusoidal data pulses
D	Use of trapezoidal data pulses

42. - E8D07

What is a common cause of overmodulation of AFSK signals?

Select	Answer
A	Excessive numbers of retries
B	Excessive transmit audio levels
C	Ground loops
D	Bit errors in the modem

43. - E9A13

What term describes station output, taking into account all gains and losses?

Select	Answer
A	Apparent power
B	Power factor
C	Half-power bandwidth
D	Effective radiated power

44. - E9B03

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

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

45. - E9C08

What is a folded dipole antenna?

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

46. - E9D02

How can linearly polarized Yagi antennas be used to produce circular polarization?

Select	Answer
A	Stack two Yagis fed 90 degrees out of phase to form an array with the respective elements in parallel planes
B	Arrange two Yagis perpendicular to each other with the driven elements at the same point on the boom fed 90 degrees out of phase
C	Stack two Yagis fed in phase to form an array with the respective elements in parallel planes
D	Arrange two Yagis collinear to each other with the driven elements fed 180 degrees out of phase

47. - E9E01

What system matches a higher-impedance transmission line to a lower-impedance antenna by connecting the line to the driven element in two places spaced a fraction of a wavelength each side of element center?

Select	Answer
A	The omega matching system
B	The delta matching system
C	The gamma matching system
D	The stub matching system

48. - E9F06

What is the approximate physical length of an air-insulated, parallel conductor transmission line that is electrically 1/2 wavelength long at 14.10 MHz?

Select	Answer
A	10.6 meters
B	7.0 meters
C	8.5 meters
D	13.3 meters

49. - E9G04

What are the two families of circles and arcs that make up a Smith chart?

Select	Answer
A	Resistance and voltage
B	Reactance and voltage
C	Voltage and impedance
D	Resistance and reactance

50. - E9H02

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

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

Figure E7-3

Figure E9-1