US Amateur Radio - Amateur Extra (Element 4, 2020-2024) Practice Test

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1. - E0A03

Over what range of frequencies are the FCC human body RF exposure limits most restrictive?

Select	Answer
A	300 kHz to 3 MHz
B	30 to 300 MHz
C	3 to 30 MHz
D	300 to 3000 MHz

2. - E1A05

What is the maximum power output permitted on the 60 meter band?

Select	Answer
A	50 watts PEP effective radiated power relative to an isotropic radiator
B	100 watts PEP effective radiated power relative to the gain of a half-wave dipole
C	50 watts PEP effective radiated power relative to a dipole
D	100 watts PEP effective radiated power relative to an isotropic radiator

3. - E1B05

What is the National Radio Quiet Zone?

Select	Answer
A	An area in New Mexico surrounding the White Sands Test Area
B	An area surrounding the National Radio Astronomy Observatory
C	An area in Florida surrounding Cape Canaveral
D	An area in Puerto Rico surrounding the Arecibo Radio Telescope

4. - E1C12

On what portion of the 630 meter band are phone emissions permitted?

Select	Answer
A	None
B	Only the bottom 3 kHz
C	Only the top 3 kHz
D	The entire band

5. - E1D01

What is the definition of telemetry?

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

6. - E1E12

What must the VE team do with the application form if the examinee does not pass the exam?

Select	Answer
A	Maintain the application form with the VEC's records
B	Send the application form to the FCC and inform the FCC of the grade
C	Destroy the application form
D	Return the application document to the examinee

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 satisfy the FCC's spurious emission standards when operated at the lesser of 1500 watts or its full output power
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 exhibit a gain of 0 dB or less over its full output range

8. - E2A03

How is the signal inverted by an inverting linear transponder?

Select	Answer
A	The signal is passed through a non-linear filter
B	The signal is reduced to I and Q components and the Q component is filtered out
C	The signal is passed through a mixer and the difference rather than the sum is transmitted
D	The signal is detected and remodulated on the reverse sideband

9. - E2B09

What hardware, other than a receiver with SSB capability and a suitable computer, is needed to decode SSTV using Digital Radio Mondiale (DRM)?

Select	Answer
A	A special front end limiter
B	A special IF converter
C	No other hardware is needed
D	A special notch filter to remove synchronization pulses

10. - E2C05

What is the function of a DX QSL Manager?

Select	Answer
A	To relay calls to and from a DX station
B	To allocate frequencies for DXpeditions
C	To run a net to allow many stations to contact a rare DX station
D	To handle the receiving and sending of confirmation cards for a DX station

11. - E2D05

What is one advantage of the JT65 mode?

Select	Answer
A	Uses only a 65 Hz bandwidth
B	Easily copied by ear if necessary
C	Permits fast-scan TV transmissions over narrow bandwidth
D	The ability to decode signals which have a very low signal-to-noise ratio

12. - E2E10

Which of these digital modes has the narrowest bandwidth?

Select	Answer
A	300-baud packet
B	MFSK16
C	PSK31
D	170 Hz shift, 45-baud RTTY

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

14. - E3B02

What is the approximate maximum range for signals using transequatorial propagation?

Select	Answer
A	1000 miles
B	2500 miles
C	7500 miles
D	5000 miles

15. - E3C11

What does VOACAP software model?

Select	Answer
A	AC voltage and impedance
B	HF propagation
C	AC current and impedance
D	VHF radio propagation

16. - E4A01

Which of the following limits the highest frequency signal that can be accurately displayed on a digital oscilloscope?

Select	Answer
A	All these choices are correct
B	Amount of memory
C	Q of the circuit
D	Sampling rate of the analog-to-digital converter

17. - E4B09

What is indicated if the current reading on an RF ammeter placed in series with the antenna feed line of a transmitter increases as the transmitter is tuned to resonance?

Select	Answer
A	There is more power going into the antenna
B	There is possibly a short to ground in the feed line
C	The transmitter is not properly neutralized
D	There is an impedance mismatch between the antenna and feed line

18. - E4C11

Why can an attenuator be used to reduce receiver overload on the lower frequency HF bands with little or no impact on signal-to-noise ratio?

Select	Answer
A	The attenuator has a noise filter to suppress interference
B	Signals are attenuated separately from the noise
C	Atmospheric noise is generally greater than internally generated noise even after attenuation
D	The attenuator has a low-pass filter to increase the strength of lower frequency signals

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

20. - E4E03

Which of the following signals might a receiver noise blanker be able to remove from desired signals?

Select	Answer
A	Signals that appear across a wide bandwidth
B	Signals that have a sharply peaked frequency distribution
C	Signals that appear at one IF but not another
D	Signals that are constant at all IF levels

21. - E5A16

What is the resonant frequency of an RLC circuit if R is 33 ohms, L is 50 microhenries and C is 10 picofarads?

Select	Answer
A	23.5 MHz
B	7.12 kHz
C	23.5 kHz
D	7.12 MHz

22. - E5B12

What is admittance?

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

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 magnitude
D	A positive phase angle

24. - E5D12

How many watts are consumed in a circuit having a power factor of 0.2 if the input is 100 VAC at 4 amperes?

Select	Answer
A	2000 watts
B	400 watts
C	80 watts
D	50 watts

25. - E6A01

In what application is gallium arsenide used as a semiconductor material?

Select	Answer
A	In high-power audio circuits
B	In microwave circuits
C	In very low-frequency RF circuits
D	In high-current rectifier circuits

26. - E6B01

What is the most useful characteristic of a Zener diode?

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

27. - E6C07

What best describes a pull-up or pull-down resistor?

Select	Answer
A	A resistor that ensures that an oscillator frequency does not drift
B	A resistor in a keying circuit used to reduce key clicks
C	A resistor connected to the positive or negative supply line used to establish a voltage when an input or output is an open circuit
D	A resistor connected to an op-amp output that prevents signals from exceeding the power supply voltage

28. - E6D06

What core material property determines the inductance of an inductor?

Select	Answer
A	Permeability
B	Reactivity
C	Thermal impedance
D	Resistance

29. - E6E12

Why are DIP through-hole package ICs not typically used at UHF and higher frequencies?

Select	Answer
A	Epoxy coating is conductive above 300 MHz
B	Too many pins
C	Unsuitable for combining analog and digital signals
D	Excessive lead length

30. - E6F11

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

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

31. - E7A05

Which of the following is a circuit that continuously alternates between two states without an external clock?

Select	Answer
A	Astable multivibrator
B	T flip-flop
C	J-K flip-flop
D	Monostable multivibrator

32. - E7B11

In Figure E7-1, what is the purpose of R3?

Select	Answer
A	Emitter bypass
B	Self bias
C	Output load resistor
D	Fixed bias

33. - E7C04

How does an impedance-matching circuit transform a complex impedance to a resistive impedance?

Select	Answer
A	Reactive currents are dissipated in matched resistances
B	It introduces negative resistance to cancel the resistive part of impedance
C	It introduces transconductance to cancel the reactive part of impedance
D	It cancels the reactive part of the impedance and changes the resistive part to a desired value

34. - E7D05

Which of the following types of linear voltage regulator places a constant load on the unregulated voltage source?

Select	Answer
A	A shunt regulator
B	A constant current source
C	A series regulator
D	A shunt current source

35. - E7E06

Why is de-emphasis commonly used in FM communications receivers?

Select	Answer
A	For compatibility with transmitters using phase modulation
B	To reduce impulse noise reception
C	For higher efficiency
D	To remove third-order distortion products

36. - E7F01

What is meant by direct digital conversion as applied to software defined radios?

Select	Answer
A	A switching mixer is used to generate I and Q signals directly from the RF input
B	Incoming RF is digitized by an analog-to-digital converter without being mixed with a local oscillator signal
C	Software is converted from source code to object code during operation of the receiver
D	Incoming RF is converted to a control voltage for a voltage controlled oscillator

37. - E7G02

What is ringing in a filter?

Select	Answer
A	An echo caused by a long time delay
B	Partial cancellation of the signal over a range of frequencies
C	A reduction in high frequency response
D	Undesired oscillations added to the desired signal

38. - E7H01

What are three oscillator circuits used in amateur radio equipment?

Select	Answer
A	Taft, Pierce and negative feedback
B	Colpitts, Hartley and Pierce
C	Taft, Hartley and Pierce
D	Pierce, Fenner and Beane

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	Fourier analysis
B	Vector analysis
C	Numerical analysis
D	Differential analysis

40. - E8B08

What describes Orthogonal Frequency Division Multiplexing?

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

41. - E8C06

What is the bandwidth of a 170-hertz shift, 300-baud ASCII transmission?

Select	Answer
A	0.1 Hz
B	1.0 kHz
C	0.3 kHz
D	0.5 kHz

42. - E8D10

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

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

43. - E9A07

What is the effective isotropic radiated power of a repeater station with 200 watts transmitter power output, 2 dB feed line loss, 2.8 dB duplexer loss, 1.2 dB circulator loss, and 7 dBi antenna gain?

Select	Answer
A	252 watts
B	63.2 watts
C	159 watts
D	632 watts

44. - E9B03

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

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

45. - E9C07

What is the approximate feed point impedance at the center of a two-wire folded dipole antenna?

Select	Answer
A	50 ohms
B	450 ohms
C	300 ohms
D	72 ohms

46. - E9D01

How much does the gain of an ideal parabolic dish antenna change when the operating frequency is doubled?

Select	Answer
A	2 dB
B	4 dB
C	6 dB
D	3 dB

47. - E9E02

What is the name of an antenna matching system that matches an unbalanced feed line to an antenna by feeding the driven element both at the center of the element and at a fraction of a wavelength to one side of center?

Select	Answer
A	The epsilon match
B	The delta match
C	The gamma match
D	The stub match

48. - E9F01

What is the velocity factor of a transmission line?

Select	Answer
A	The ratio of the characteristic impedance of the line to the terminating impedance
B	The velocity of the wave in the transmission line divided by the velocity of light in a vacuum
C	The index of shielding for coaxial cable
D	The velocity of the wave in the transmission line multiplied by the velocity of light in a vacuum

49. - E9G01

Which of the following can be calculated using a Smith chart?

Select	Answer
A	Antenna radiation pattern
B	Radio propagation
C	Impedance along transmission lines
D	Radiation resistance

50. - E9H09

What is a Pennant antenna?

Select	Answer
A	A small, vertically oriented receiving antenna consisting of a triangular loop terminated in approximately 900 ohms
B	A stealth antenna built to look like a flagpole
C	A form of rhombic antenna terminated in a variable capacitor to provide frequency diversity
D	A four-element, high-gain vertical array invented by George Pennant

Figure E7-1

Figure E9-1