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	Any ordinary smoke detector can be used
C	By the yellowish appearance of the gas
D	By the odor

2. - E1A11

Which of the following describes authorization or licensing required when operating an amateur station aboard a U.S.-registered vessel in international waters?

Select	Answer
A	Only General Class or higher amateur licenses
B	Any amateur license with an FCC Marine or Aircraft endorsement
C	Any FCC-issued amateur license
D	An unrestricted Radiotelephone Operator Permit

3. - E1B10

What frequencies are authorized to an amateur station operating under RACES rules?

Select	Answer
A	All amateur service frequencies authorized to the control operator
B	Specific local government channels
C	Military Auxiliary Radio System (MARS) channels
D	Specific segments in the amateur service MF, HF, VHF and UHF bands

4. - E1C05

When may an automatically controlled station originate third party communications?

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

5. - E1D03

What is a space telecommand station?

Select	Answer
A	An amateur station located in a satellite or a balloon more than 50 kilometers above the surface of the Earth
B	An amateur station located on the surface of the Earth for communication with other Earth stations by means of Earth satellites
C	An amateur station that transmits communications to initiate, modify or terminate functions of a space station
D	An amateur station that receives telemetry from a satellite or balloon more than 50 kilometers above the surface of the Earth

6. - E1E09

What may be the penalty for a VE who fraudulently administers or certifies an examination?

Select	Answer
A	All these choices are correct
B	Revocation of the VE's amateur station license grant and the suspension of the VE's amateur operator license grant
C	A fine of up to $1000 per occurrence
D	A sentence of up to one year in prison

7. - E1F11

Which of the following best describes one of the standards that must be met by an external RF power amplifier if it is to qualify for a grant of FCC certification?

Select	Answer
A	It must exhibit a gain of 0 dB or less over its full output range
B	It must produce full legal output when driven by not more than 5 watts of mean RF input power
C	It must be capable of external RF switching between its input and output networks
D	It must satisfy the FCC's spurious emission standards when operated at the lesser of 1500 watts or its full output power

8. - E2A07

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

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

9. - E2B10

What aspect of an analog slow-scan television signal encodes the brightness of the picture?

Select	Answer
A	Sync frequency
B	Tone amplitude
C	Tone frequency
D	Sync amplitude

10. - E2C04

Which of the following frequencies are sometimes used for amateur radio mesh networks?

Select	Answer
A	Cable TV channels 41 through 43
B	Frequencies shared with various unlicensed wireless data services
C	The 60 meter band channel centered on 5373 kHz
D	HF frequencies where digital communications are permitted

11. - E2D04

What technology is used to track, in real time, balloons carrying amateur radio transmitters?

Select	Answer
A	Bandwidth compressed LORAN
B	Doppler shift of beacon signals
C	APRS
D	Ultrasonics

12. - E2E03

How is the timing of FT4 contacts organized?

Select	Answer
A	By exchanging ACK/NAK packets
B	Alternating transmissions at 7.5 second intervals
C	It depends on the lunar phase
D	Stations take turns on alternate days

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 MUF is above 30 MHz
C	When the moon is full
D	When the moon is at perigee

14. - E3B07

What happens to linearly polarized radio waves that split into ordinary and extraordinary waves in the ionosphere?

Select	Answer
A	They become elliptically polarized
B	They become phase locked
C	They become depolarized
D	They are bent toward the magnetic poles

15. - E3C10

What does the 304A solar parameter measure?

Select	Answer
A	The solar emission at 304 GHz, correlated to x-ray flare levels
B	UV emissions at 304 angstroms, correlated to the solar flux index
C	The solar wind velocity at 304 degrees from the solar equator, correlated to solar activity
D	The ratio of x-ray flux to radio flux, correlated to sunspot number

16. - E4A07

Which of the following is an advantage of using an antenna analyzer compared to an SWR bridge to measure antenna SWR?

Select	Answer
A	All these choices are correct
B	Antenna analyzers automatically tune your antenna for resonance
C	Antenna analyzers do not need an external RF source
D	Antenna analyzers display a time-varying representation of the modulation envelope

17. - E4B08

Which of the following can be used to measure the Q of a series-tuned circuit?

Select	Answer
A	The bandwidth of the circuit's frequency response
B	The resonant frequency of the circuit
C	The inductance to capacitance ratio
D	The frequency shift

18. - E4C03

What is the term for the suppression in an FM receiver of one signal by another stronger signal on the same frequency?

Select	Answer
A	Cross-modulation interference
B	Frequency discrimination
C	Capture effect
D	Desensitization

19. - E4D11

Why are odd-order intermodulation products, created within a receiver, of particular interest compared to other products?

Select	Answer
A	Odd-order intermodulation produces three products for every input signal within the band of interest
B	Odd-order products of two signals in the band of interest are also likely to be within the band
C	Odd-order products are an indication of poor image rejection
D	Odd-order products overload the IF filters

20. - E4E11

What could cause local AM broadcast band signals to combine to generate spurious signals in the MF or HF bands?

Select	Answer
A	Nearby corroded metal joints are mixing and re-radiating the broadcast signals
B	You are receiving skywave signals from a distant station
C	One or more of the broadcast stations is transmitting an over-modulated signal
D	Your station receiver IF amplifier stage is defective

21. - E5A09

How is the Q of an RLC parallel resonant circuit calculated?

Select	Answer
A	Reactance of the inductance multiplied by the reactance of the capacitance
B	Reactance of either the inductance or capacitance multiplied by the resistance
C	Reactance of either the inductance or capacitance divided by the resistance
D	Resistance divided by the reactance of either the inductance or capacitance

22. - E5B01

What is the term for the time required for the capacitor in an RC circuit to be charged to 63.2% of the applied voltage or to discharge to 36.8% of its initial voltage?

Select	Answer
A	One time constant
B	One exponential period
C	An exponential rate of one
D	A time factor of one

23. - E5C12

Which point on Figure E5-1 best represents the impedance of a series circuit consisting of a 300-ohm resistor and a 19-picofarad capacitor at 21.200 MHz?

Select	Answer
A	Point 7
B	Point 8
C	Point 1
D	Point 3

24. - E5D11

What is the power factor of an RL circuit having a 60-degree phase angle between the voltage and the current?

Select	Answer
A	0.5
B	1.73
C	0.866
D	1.414

25. - E6A10

In Figure E6-1, what is the schematic symbol for an N-channel dual-gate MOSFET?

Select	Answer
A	6
B	2
C	5
D	4

26. - E6B11

What is used to control the attenuation of RF signals by a PIN diode?

Select	Answer
A	A sub-harmonic pump signal
B	Reverse voltage larger than the RF signal
C	Forward DC bias current
D	Capacitance of an RF coupling capacitor

27. - E6C06

Why do CMOS digital integrated circuits have high immunity to noise on the input signal or power supply?

Select	Answer
A	The input switching threshold is about two times the power supply voltage
B	Large bypass capacitance is inherent
C	Bandwidth is very limited
D	The input switching threshold is about one-half the power supply voltage

28. - E6D07

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

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

29. - E6E02

Which of the following device packages is a through-hole type?

Select	Answer
A	DIP
B	SOT
C	Ball grid array
D	PLCC

30. - E6F11

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

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

31. - E7A07

What logical operation does a NAND gate perform?

Select	Answer
A	It produces logic 1 at its output only when all inputs are logic 1
B	It produces logic 0 at its output only when all inputs are logic 1
C	It produces logic 0 at its output if some but not all inputs are logic 1
D	It produces logic 0 at its output only when all inputs are logic 0

32. - E7B12

What type of amplifier circuit is shown in Figure E7-1?

Select	Answer
A	Emitter follower
B	Common collector
C	Common base
D	Common emitter

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	Pi-networks provide balanced input and output
C	Pi-networks are more stable
D	L-networks cannot perform impedance transformation

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

35. - E7E09

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

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

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. - 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	Restrict Q but increase gain
C	Increase both gain and Q
D	Restrict gain but increase Q

38. - E7H05

How is positive feedback supplied in a Pierce oscillator?

Select	Answer
A	Through a tapped coil
B	Through a neutralizing capacitor
C	Through a quartz crystal
D	Through link coupling

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	Numerical analysis
B	Differential analysis
C	Fourier analysis
D	Vector analysis

40. - E8B08

What describes Orthogonal Frequency Division Multiplexing?

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

41. - E8C11

What is the relationship between symbol rate and baud?

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

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 6 data bits per character, ASCII uses 7 or 8; Baudot has no letters/figures shift code, ASCII uses 2 letters/figures shift codes
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. - E9A06

What is the effective radiated power relative to a dipole of a repeater station with 200 watts transmitter power output, 4 dB feed line loss, 3.2 dB duplexer loss, 0.8 dB circulator loss, and 10 dBd antenna gain?

Select	Answer
A	317 watts
B	2000 watts
C	300 watts
D	126 watts

44. - E9B05

What type of antenna pattern is shown in Figure E9-2?

Select	Answer
A	Elevation
B	Azimuth
C	Polarization
D	Radiation resistance

45. - E9C06

What is the effect of adding a terminating resistor to a rhombic antenna?

Select	Answer
A	It changes the radiation pattern from bidirectional to unidirectional
B	It reflects the standing waves on the antenna elements back to the transmitter
C	It changes the radiation pattern from horizontal to vertical polarization
D	It decreases the ground loss

46. - E9D03

Where should a high Q loading coil be placed to minimize losses in a shortened vertical antenna?

Select	Answer
A	As close to the transmitter as possible
B	As low as possible on the vertical radiator
C	Near the center of the vertical radiator
D	At a voltage node

47. - E9E09

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

Select	Answer
A	Hairpin match
B	Gamma match
C	Double-bazooka match
D	All these choices are correct

48. - E9F08

Which of the following is a significant difference between foam dielectric coaxial cable and solid dielectric cable, assuming all other parameters are the same?

Select	Answer
A	All these choices are correct
B	Foam dielectric has lower loss per unit of length
C	Foam dielectric has lower safe operating voltage limits
D	Foam dielectric has higher velocity factor

49. - E9G06

On the Smith chart shown in Figure E9-3, what is the name for the large outer circle on which the reactance arcs terminate?

Select	Answer
A	Impedance axis
B	Reactance axis
C	Prime axis
D	Polar axis

50. - E9H08

What is the function of a sense antenna?

Select	Answer
A	It modifies the pattern of a DF antenna array to provide a null in one direction
B	It provides diversity reception that cancels multipath signals
C	It allows DF antennas to receive signals at different vertical angles
D	It increases the sensitivity of a DF antenna array

Figure E5-1

Figure E6-1

Figure E7-1

Figure E9-2

Figure E9-3