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. - E1A14

Except in some parts of Alaska, what is the maximum power permitted on the 630 meter band?

Select	Answer
A	50 watts PEP
B	1 watt EIRP
C	5 watts EIRP
D	100 watts PEP

3. - E1B08

What limitations may the FCC place on an amateur station if its signal causes interference to domestic broadcast reception, assuming that the receivers involved are of good engineering design?

Select	Answer
A	The amateur station must avoid transmitting during certain hours on frequencies that cause the interference
B	The amateur station must cease operation
C	The amateur station must cease operation on all frequencies below 30 MHz
D	The amateur station must cease operation on all frequencies above 30 MHz

4. - E1C05

When may an automatically controlled station originate third party communications?

Select	Answer
A	Only when transmitting RTTY or data emissions
B	When approved by the National Telecommunication and Information Administration
C	When agreed upon by the sending or receiving station
D	Never

5. - E1D08

Which VHF amateur bands have frequencies authorized for space stations?

Select	Answer
A	6 meters and 2 meters
B	6 meters, 2 meters, and 1.25 meters
C	2 meters
D	2 meters and 1.25 meters

6. - E1E10

What must the administering VEs do after the administration of a successful examination for an amateur operator license?

Select	Answer
A	They must collect and submit the documents to the coordinating VEC for grading
B	They must submit the application document to the coordinating VEC according to the coordinating VEC instructions
C	They must collect and send the documents to the NCVEC for grading
D	They must collect and send the documents to the FCC according to instructions

7. - E1F09

Which of the following conditions apply when transmitting spread spectrum emissions?

Select	Answer
A	All these choices are correct
B	The transmitting station must be in an area regulated by the FCC or in a country that permits SS emissions
C	A station transmitting SS emission must not cause harmful interference to other stations employing other authorized emissions
D	The transmission must not be used to obscure the meaning of any communication

8. - E2A01

What is the direction of an ascending pass for an amateur satellite?

Select	Answer
A	From south to north
B	From east to west
C	From north to south
D	From west to east

9. - E2B01

How many times per second is a new frame transmitted in a fast-scan (NTSC) television system?

Select	Answer
A	60
B	30
C	90
D	120

10. - E2C09

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

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

11. - E2D03

Which of the following digital modes is especially useful for EME communications?

Select	Answer
A	JT65
B	Olivia
C	MSK144
D	PACTOR III

12. - E2E07

Which of the following is a possible reason that attempts to initiate contact with a digital station on a clear frequency are unsuccessful?

Select	Answer
A	Another station you are unable to hear is using the frequency
B	All these choices are correct
C	The protocol version you are using is not supported by the digital station
D	Your transmit frequency is incorrect

13. - E3A09

Which of the following frequency ranges is most suited for meteor scatter communications?

Select	Answer
A	1.8 MHz - 1.9 MHz
B	10 MHz - 14 MHz
C	220 MHz - 450 MHz
D	28 MHz - 148 MHz

14. - E3B12

What is the primary characteristic of chordal hop propagation?

Select	Answer
A	Propagation across the geomagnetic equator
B	Propagation away from the great circle bearing between stations
C	Signals reflected back toward the transmitting station
D	Successive ionospheric refractions without an intermediate reflection from the ground

15. - E3C12

How does the maximum range of ground-wave propagation change when the signal frequency is increased?

Select	Answer
A	It peaks at roughly 14 MHz
B	It decreases
C	It stays the same
D	It increases

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. - E4B07

What do the subscripts of S parameters represent?

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

18. - E4C15

What is reciprocal mixing?

Select	Answer
A	In-phase signals cancelling in a mixer resulting in loss of receiver sensitivity
B	Local oscillator phase noise mixing with adjacent strong signals to create interference to desired signals
C	Two out-of-band signals mixing to generate an in-band spurious signal
D	Two digital signals combining from alternate time slots

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

20. - E4E07

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

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

21. - E5A14

What is the resonant frequency of an RLC circuit if R is 22 ohms, L is 50 microhenries and C is 40 picofarads?

Select	Answer
A	1.78 MHz
B	44.72 MHz
C	3.56 MHz
D	22.36 MHz

22. - E5B10

What is the relationship between the AC current through an inductor and the voltage across an inductor?

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

23. - E5C04

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

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

24. - E5D05

What is the power factor of an RL circuit having a 30-degree phase angle between the voltage and the current?

Select	Answer
A	1.73
B	0.5
C	0.866
D	0.577

25. - E6A06

What is the beta of a bipolar junction transistor?

Select	Answer
A	The change in collector current with respect to base current
B	The breakdown voltage of the base to collector junction
C	The frequency at which the current gain is reduced to 0.707
D	The switching speed

26. - E6B03

What type of bias is required for an LED to emit light?

Select	Answer
A	Inductive bias
B	Forward bias
C	Reverse bias
D	Zero bias

27. - E6C04

Which of the following is an advantage of BiCMOS logic?

Select	Answer
A	It has the high input impedance of CMOS and the low output impedance of bipolar transistors
B	All these choices are correct
C	It is immune to electrostatic damage
D	Its simplicity results in much less expensive devices than standard CMOS

28. - E6D08

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

Select	Answer
A	Powdered-iron cores generally have greater initial permeability
B	Powdered-iron cores generally require fewer turns to produce a given inductance
C	Powdered-iron cores generally maintain their characteristics at higher currents
D	Powdered-iron cores use smaller diameter wire for the same inductance

29. - E6E05

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

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

30. - E6F04

What is the photovoltaic effect?

Select	Answer
A	The conversion of light to electrical energy
B	The conversion of voltage to current when exposed to light
C	The conversion of electrical energy to mechanical energy
D	The tendency of a battery to discharge when exposed to light

31. - E7A10

What is a truth table?

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

32. - E7B13

Which of the following describes an emitter follower (or common collector) amplifier?

Select	Answer
A	An OR circuit with only one emitter used for output
B	An amplifier with a low impedance output that follows the base input voltage
C	A differential amplifier with both inputs fed to the emitter of the input transistor
D	A two-transistor amplifier with the emitters sharing a common bias resistor

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

34. - E7D09

What is the main reason to use a charge controller with a solar power system?

Select	Answer
A	Prevention of battery undercharge
B	Matching of day and night charge rates
C	Control of electrolyte levels during battery discharge
D	Prevention of battery damage due to overcharge

35. - E7E01

Which of the following can be used to generate FM phone emissions?

Select	Answer
A	A reactance modulator on the final amplifier
B	A reactance modulator on the oscillator
C	A balanced modulator on the oscillator
D	A balanced modulator on the audio amplifier

36. - E7F05

How frequently must an analog signal be sampled by an analog-to-digital converter so that the signal can be accurately reproduced?

Select	Answer
A	At least twice the rate of the highest frequency component of the signal
B	At least half the rate of the highest frequency component of the signal
C	At four times the rate of the highest frequency component of the signal
D	At the same rate as the highest frequency component of the signal

37. - E7G08

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

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

38. - E7H03

How is positive feedback supplied in a Hartley oscillator?

Select	Answer
A	Through a tapped coil
B	Through a neutralizing capacitor
C	Through a capacitive divider
D	Through link coupling

39. - E8A04

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

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

40. - E8B08

What describes Orthogonal Frequency Division Multiplexing?

Select	Answer
A	A digital mode for narrow-band, slow-speed transmissions
B	A digital modulation technique using subcarriers at frequencies chosen to avoid intersymbol interference
C	A bandwidth compression technique using Fourier transforms
D	A frequency modulation technique that uses non-harmonically related frequencies

41. - E8C02

What is the definition of symbol rate in a digital transmission?

Select	Answer
A	The number of control characters in a message packet
B	The duration of each bit in a message sent over the air
C	The rate at which the waveform changes to convey information
D	The number of characters carried per second by the station-to-station link

42. - E8D10

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

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

43. - E9A04

Which of the following factors affect the feed point impedance of an antenna?

Select	Answer
A	Antenna height
B	The settings of an antenna tuner at the transmitter
C	The input power level
D	Transmission line length

44. - E9B01

In the antenna radiation pattern shown in Figure E9-1, what is the beamwidth?

Select	Answer
A	75 degrees
B	30 degrees
C	50 degrees
D	25 degrees

45. - E9C13

How does the radiation pattern of a horizontally polarized 3-element beam antenna vary with increasing height above ground?

Select	Answer
A	The horizontal beamwidth increases
B	The horizontal beamwidth decreases
C	The takeoff angle of the lowest elevation lobe decreases
D	The takeoff angle of the lowest elevation lobe increases

46. - E9D11

Which of the following conductors would be best for minimizing losses in a station's RF ground system?

Select	Answer
A	Solid wire
B	Stranded wire
C	Wide flat copper strap
D	Resistive wire, such as spark plug wire

47. - E9E08

What is a use for a Wilkinson divider?

Select	Answer
A	It is used to feed low-impedance loads from a high-impedance source
B	It is used to feed high-impedance antennas from a low-impedance source
C	It is used to divide power equally between two 50-ohm loads while maintaining 50-ohm input impedance
D	It divides the operating frequency of a transmitter signal so it can be used on a lower frequency band

48. - E9F09

What is the approximate physical length of a foam polyethylene dielectric coaxial transmission line that is electrically 1/4 wavelength long at 7.2 MHz?

Select	Answer
A	8.3 meters
B	10.4 meters
C	6.9 meters
D	5.2 meters

49. - E9G11

How are the wavelength scales on a Smith chart calibrated?

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

50. - E9H01

When constructing a Beverage antenna, which of the following factors should be included in the design to achieve good performance at the desired frequency?

Select	Answer
A	It must be mounted more than 1 wavelength above ground
B	It should be one or more wavelengths long
C	It should be configured as a four-sided loop
D	Its overall length must not exceed 1/4 wavelength

Figure E9-1