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

2. - E1A01

Which of the following carrier frequencies is illegal for LSB AFSK emissions on the 17 meter band RTTY and data segment of 18.068 to 18.110 MHz?

Select	Answer
A	18.110 MHz
B	18.068 MHz
C	18.107 MHz
D	18.100 MHz

3. - E1B09

Which amateur stations may be operated under RACES rules?

Select	Answer
A	Any FCC-licensed amateur station certified by the responsible civil defense organization for the area served
B	Only those club stations licensed to Amateur Extra Class operators
C	Any FCC-licensed amateur station participating in the Military Auxiliary Radio System (MARS)
D	Any FCC-licensed amateur station except a Technician Class

4. - E1C05

When may an automatically controlled station originate third party communications?

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

5. - E1D05

What must be posted at the station location of a station being operated by telecommand on or within 50 km of the earth's surface?

Select	Answer
A	A label with the name, address, and telephone number of the station licensee
B	A label with the name, address, and telephone number of the control operator
C	All these choices are correct
D	A photocopy of the station license

6. - E1E01

For which types of out-of-pocket expenses do the Part 97 rules state that VEs and VECs may be reimbursed?

Select	Answer
A	Teaching an amateur operator license examination preparation course
B	No expenses are authorized for reimbursement
C	Providing amateur operator license examination preparation training materials
D	Preparing, processing, administering, and coordinating an examination for an amateur radio operator license

7. - E1F05

Amateur stations may not transmit in which of the following frequency segments if they are located in the contiguous 48 states and north of Line A?

Select	Answer
A	53 MHz - 54 MHz
B	440 MHz - 450 MHz
C	222 MHz - 223 MHz
D	420 MHz - 430 MHz

8. - E2A13

Which of the following techniques is normally used by low Earth orbiting digital satellites to relay messages around the world?

Select	Answer
A	Store-and-forward
B	Node hopping
C	Multi-satellite relaying
D	Digipeating

9. - E2B05

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

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

10. - E2C02

Which of the following best describes the term self-spotting? in connection with HF contest operating?

Select	Answer
A	An automatic method for rapidly zero beating or tuning to a station's frequency before calling that station
B	The acceptable practice of manually posting the call signs of stations on a spotting network
C	The often-prohibited practice of posting one's own call sign and frequency on a spotting network
D	A manual technique for rapidly zero beating or tuning to a station's frequency before calling that station

11. - E2D06

Which of the following describes a method of establishing EME contacts?

Select	Answer
A	Storing and forwarding digital messages
B	Time synchronous transmissions alternately from each station
C	High-speed CW identification to avoid fading
D	Judging optimum transmission times by monitoring beacons reflected from the moon

12. - E2E01

Which of the following types of modulation is common for data emissions below 30 MHz?

Select	Answer
A	Pulse modulation
B	Spread spectrum
C	FSK
D	DTMF tones modulating an FM signal

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

14. - E3B05

Which amateur bands typically support long-path propagation?

Select	Answer
A	Only 30 meters to 10 meters
B	6 meters to 2 meters
C	160 meters to 10 meters
D	Only 160 meters to 40 meters

15. - E3C07

Which of the following descriptors indicates the greatest solar flare intensity?

Select	Answer
A	Class A
B	Class B
C	Class M
D	Class X

16. - E4A08

Which of the following measures SWR?

Select	Answer
A	A spectrum analyzer
B	An antenna analyzer
C	A Q meter
D	An ohmmeter

17. - E4B02

What is the significance of voltmeter sensitivity expressed in ohms per volt?

Select	Answer
A	When used as an ammeter, the full scale reading in amps divided by ohms per volt rating will determine the size of shunt needed
B	When used as a galvanometer, the reading in volts multiplied by the ohms per volt rating will determine the power drawn by the device under test
C	When used as an ohmmeter, the reading in ohms divided by the ohms per volt rating will determine the voltage applied to the circuit
D	The full scale reading of the voltmeter multiplied by its ohms per volt rating will indicate the input impedance of the voltmeter

18. - E4C05

What does a receiver noise floor of -174 dBm represent?

Select	Answer
A	The noise figure of a 1 Hz bandwidth receiver
B	The minimum detectable signal as a function of receive frequency
C	The galactic noise contribution to minimum detectable signal
D	The theoretical noise in a 1 Hz bandwidth at the input of a perfect receiver at room temperature

19. - E4D02

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

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

20. - E4E05

How can radio frequency interference from an AC motor be suppressed?

Select	Answer
A	By using a ground-fault current interrupter in the circuit used to power the motor
B	By installing a high-pass filter in series with the motor's power leads
C	By installing a bypass capacitor in series with the motor leads
D	By installing a brute-force AC-line filter in series with the motor leads

21. - E5A13

What is an effect of increasing Q in a series resonant circuit?

Select	Answer
A	Parasitic effects are minimized
B	Fewer components are needed for the same performance
C	Internal voltages increase
D	Phase shift can become uncontrolled

22. - E5B12

What is admittance?

Select	Answer
A	The inverse of Q factor
B	The turns ratio of a transformer
C	The term for the gain of a field effect transistor
D	The inverse of impedance

23. - E5C01

Which of the following represents capacitive reactance in rectangular notation?

Select	Answer
A	+jX
B	-jX
C	Omega
D	Delta

24. - E5D09

What happens to reactive power in an AC circuit that has both ideal inductors and ideal capacitors?

Select	Answer
A	It is dissipated as heat in the circuit
B	It is repeatedly exchanged between the associated magnetic and electric fields, but is not dissipated
C	It is dissipated in the formation of inductive and capacitive fields
D	It is dissipated as kinetic energy in the circuit

25. - E6A05

How does DC input impedance at the gate of a field-effect transistor compare with the DC input impedance of a bipolar transistor?

Select	Answer
A	An FET has higher input impedance
B	An FET has lower input impedance
C	They are both high impedance
D	They are both low impedance

26. - E6B10

In Figure E6-2, what is the schematic symbol for a light-emitting diode?

Select	Answer
A	1
B	7
C	6
D	5

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	It is immune to electrostatic damage
C	All these choices are correct
D	Its simplicity results in much less expensive devices than standard CMOS

28. - E6D07

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

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

29. - E6E10

What advantage does surface-mount technology offer at RF compared to using through-hole components?

Select	Answer
A	All these choices are correct
B	Shorter circuit-board traces
C	Components have less parasitic inductance and capacitance
D	Smaller circuit area

30. - E6F08

Why are optoisolators often used in conjunction with solid-state circuits when switching 120 VAC?

Select	Answer
A	Optoisolators provide a low impedance link between a control circuit and a power circuit
B	Optoisolators provide a very high degree of electrical isolation between a control circuit and the circuit being switched
C	Optoisolators provide impedance matching between the control circuit and power circuit
D	Optoisolators eliminate the effects of reflected light in the control circuit

31. - E7A03

Which of the following can divide the frequency of a pulse train by 2?

Select	Answer
A	A multiplexer
B	An XOR gate
C	An OR gate
D	A flip-flop

32. - E7B09

Which of the following describes how the loading and tuning capacitors are to be adjusted when tuning a vacuum tube RF power amplifier that employs a Pi-network output circuit?

Select	Answer
A	The tuning capacitor is set to maximum capacitance and the loading capacitor is adjusted for minimum plate permissible current
B	The tuning capacitor is adjusted for minimum plate current, and the loading capacitor is adjusted for maximum permissible plate current
C	The loading capacitor is adjusted to minimum plate current while alternately adjusting the tuning capacitor for maximum allowable plate current
D	The loading capacitor is set to maximum capacitance and the tuning capacitor is adjusted for minimum allowable plate current

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

34. - E7D12

What is the dropout voltage of an analog voltage regulator?

Select	Answer
A	Minimum input-to-output voltage required to maintain regulation
B	Minimum input voltage for rated power dissipation
C	Maximum output voltage drops when the input voltage is varied over its specified range
D	Maximum that the output voltage may decrease at rated load

35. - E7E07

What is meant by the term "baseband" in radio communications?

Select	Answer
A	The lowest frequency band that the transmitter or receiver covers
B	The frequency range occupied by a message signal prior to modulation
C	The unmodulated bandwidth of the transmitted signal
D	The basic oscillator frequency in an FM transmitter that is multiplied to increase the deviation and carrier frequency

36. - E7F04

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

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

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	7
B	28
C	14
D	0.07

38. - E7H03

How is positive feedback supplied in a Hartley oscillator?

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

39. - E8A01

What is the name of the process that shows that a square wave is made up of a sine wave plus all its odd harmonics?

Select	Answer
A	Vector analysis
B	Differential analysis
C	Numerical analysis
D	Fourier analysis

40. - E8B03

What is the modulation index of an FM-phone signal having a maximum frequency deviation of 3000 Hz either side of the carrier frequency when the modulating frequency is 1000 Hz?

Select	Answer
A	3
B	0.3
C	1000
D	3000

41. - E8C10

How may data rate be increased without increasing bandwidth?

Select	Answer
A	Using a more efficient digital code
B	Increasing analog-to-digital conversion resolution
C	It is impossible
D	Using forward error correction

42. - E8D04

What is the primary effect of extremely short rise or fall time on a CW signal?

Select	Answer
A	The generation of key clicks
B	More difficult to copy
C	The generation of RF harmonics
D	Limits data speed

43. - E9A09

What is antenna efficiency?

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

44. - E9B06

What is the elevation angle of peak response in the antenna radiation pattern shown in Figure E9-2?

Select	Answer
A	45 degrees
B	7.5 degrees
C	25 degrees
D	75 degrees

45. - E9C09

Which of the following describes a G5RV antenna?

Select	Answer
A	A multi-band trap antenna
B	A phased array antenna consisting of multiple loops
C	A multi-band dipole antenna fed with coax and a balun through a selected length of open wire transmission line
D	A wide band dipole using shorted coaxial cable for the radiating elements and fed with a�4:1 balun

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 collinear to each other with the driven elements fed 180 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 perpendicular to each other with the driven elements at the same point on the boom fed 90 degrees out of phase

47. - E9E04

What is the purpose of the series capacitor in a gamma-type antenna matching network?

Select	Answer
A	To provide a rejection notch that prevents the radiation of harmonics
B	To transform the antenna impedance to a higher value
C	To provide DC isolation between the feed line and the antenna
D	To cancel the inductive reactance of the matching network

48. - E9F13

What impedance does a 1/4-wavelength transmission line present to a generator when the line is shorted at the far end?

Select	Answer
A	The same as the characteristic impedance of the transmission line
B	Very high impedance
C	Very low impedance
D	The same as the generator output impedance

49. - E9G05

Which of the following is a common use for a Smith chart?

Select	Answer
A	Determine the loss/100 feet of a transmission line, given the velocity factor and conductor materials
B	Determine the gain of an antenna given the physical and electrical parameters
C	Determine the impedance of a transmission line, given the physical dimensions
D	Determine the length and position of an impedance matching stub

50. - E9H11

What feature of a cardioid pattern antenna makes it useful for direction finding?

Select	Answer
A	Broadband response
B	A very sharp single null
C	High radiation angle
D	A very sharp peak

Figure E6-2

Figure E7-3

Figure E9-2