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

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1. - E0A01

What is the primary function of an external earth connection or ground rod?

Select	Answer
A	Reduce RFI to telephones and home entertainment systems
B	Lightning protection
C	Reduce received noise
D	Reduce RF current flow between pieces of equipment

2. - E1A07

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

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

3. - E1B05

What is the National Radio Quiet Zone?

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

4. - E1C12

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

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

5. - E1D10

Which amateur stations are eligible to be telecommand stations of space stations (subject to the privileges of the class of operator license held by the control operator of the station)?

Select	Answer
A	Any amateur station so designated by the ITU
B	Any amateur station so designated by the space station licensee
C	All these choices are correct
D	Any amateur station designated by NASA

6. - E1E08

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

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

7. - E1F09

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

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

8. - E2A05

What do the letters in a satellite's mode designator specify?

Select	Answer
A	The polarization of uplink and downlink signals
B	Power limits for uplink and downlink transmissions
C	The location of the ground control station
D	The uplink and downlink frequency ranges

9. - E2B12

What signals SSTV receiving software to begin a new picture line?

Select	Answer
A	Specific tone amplitudes
B	Elapsed time
C	Specific tone frequencies
D	A two-tone signal

10. - E2C01

What indicator is required to be used by U.S.-licensed operators when operating a station via remote control and the remote transmitter is located in the U.S.?

Select	Answer
A	/R# where # is the district of the remote station
B	/ followed by the ARRL Section of the remote station
C	No additional indicator is required
D	/ followed by the USPS two-letter abbreviation for the state in which the remote station is located

11. - E2D03

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

Select	Answer
A	Olivia
B	PACTOR III
C	JT65
D	MSK144

12. - E2E13

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

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

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

14. - E3B12

What is the primary characteristic of chordal hop propagation?

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

15. - E3C11

What does VOACAP software model?

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

16. - E4A03

Which of the following test instruments is used to display spurious signals and/or intermodulation distortion products generated by an SSB transmitter?

Select	Answer
A	A time-domain reflectometer
B	A spectrum analyzer
C	A wattmeter
D	A logic analyzer

17. - E4B07

What do the subscripts of S parameters represent?

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

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

19. - E4D02

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

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

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

21. - E5A08

What is the phase relationship between the current through and the voltage across a series resonant circuit at resonance?

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

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

23. - E5C09

When using rectangular coordinates to graph the impedance of a circuit, what do the axes represent?

Select	Answer
A	The X axis represents the magnitude and the Y axis represents the phase angle
B	The X axis represents the reactive component and the Y axis represents the resistive component
C	The X axis represents the phase angle and the Y axis represents the magnitude
D	The X axis represents the resistive component and the Y axis represents the reactive component

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	50 watts
B	2000 watts
C	400 watts
D	80 watts

25. - E6A02

Which of the following semiconductor materials contains excess free electrons?

Select	Answer
A	N-type
B	P-type
C	Insulated gate
D	Bipolar

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	An internal capacitance that varies with the applied voltage
D	A constant voltage drop under conditions of varying current

27. - E6C01

What is the function of hysteresis in a comparator?

Select	Answer
A	To prevent input noise from causing unstable output signals
B	To allow the comparator to be used with AC input signals
C	To cause the output to change states continually
D	To increase the sensitivity

28. - E6D03

Which of the following is an aspect of the piezoelectric effect?

Select	Answer
A	Mechanical deformation of material by the application of a magnetic field
B	Mechanical deformation of material by the application of a voltage
C	Increased conductivity in the presence of light
D	Generation of electrical energy in the presence of light

29. - E6E05

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

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

30. - E6F08

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

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

31. - E7A06

What is a characteristic of a monostable multivibrator?

Select	Answer
A	It maintains a constant output voltage, regardless of variations in the input voltage
B	It stores one bit of data in either a 0 or 1 state
C	It switches momentarily to the opposite binary state and then returns to its original state after a set time
D	It produces a continuous square wave oscillating between 1 and 0

32. - E7B10

In Figure E7-1, what is the purpose of R1 and R2?

Select	Answer
A	Self bias
B	Feedback
C	Load resistors
D	Voltage divider bias

33. - E7C06

What are the distinguishing features of an elliptical filter?

Select	Answer
A	Gradual passband rolloff with minimal stop band ripple
B	Gradual passband rolloff with extreme stop band ripple
C	Extremely flat response over its pass band with gradually rounded stop band corners
D	Extremely sharp cutoff with one or more notches in the stop band

34. - E7D11

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

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

35. - E7E10

How does a diode envelope detector function?

Select	Answer
A	By rectification and filtering of RF signals
B	By sensing the change of reactance in the diode with respect to frequency
C	By breakdown of the Zener voltage
D	By mixing signals with noise in the transition region of the diode

36. - E7F09

Why is an anti-aliasing digital filter required in a digital decimator?

Select	Answer
A	It removes high-frequency signal components that would otherwise be reproduced as lower frequency components
B	It notches out the sampling frequency to avoid sampling errors
C	It removes low-frequency signal components to eliminate the need for DC restoration
D	It peaks the response of the decimator, improving bandwidth

37. - E7G12

What is an operational amplifier?

Select	Answer
A	A digital audio amplifier whose characteristics are determined by components external to the amplifier
B	An amplifier used to increase the average output of frequency modulated amateur signals to the legal limit
C	A RF amplifier used in the UHF and microwave regions
D	A high-gain, direct-coupled differential amplifier with very high input impedance and very low output impedance

38. - E7H14

What is a phase-locked loop circuit?

Select	Answer
A	An electronic circuit also known as a monostable multivibrator
B	An electronic circuit consisting of a precision push-pull amplifier with a differential input
C	An electronic servo loop consisting of a ratio detector, reactance modulator, and voltage-controlled oscillator
D	An electronic servo loop consisting of a phase detector, a low-pass filter, a voltage-controlled oscillator, and a stable reference oscillator

39. - E8A11

Which of the following is a measure of the quality of an analog-to-digital converter?

Select	Answer
A	Peak envelope power
B	Total harmonic distortion
C	Reciprocal mixing
D	Power factor

40. - E8B09

What is deviation ratio?

Select	Answer
A	The ratio of the audio modulating frequency to the center carrier frequency
B	The ratio of the maximum carrier frequency deviation to the highest audio modulating frequency
C	The ratio of the highest audio modulating frequency to the average audio modulating frequency
D	The ratio of the carrier center frequency to the audio modulating frequency

41. - E8C10

How may data rate be increased without increasing bandwidth?

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

42. - E8D03

How does the spread spectrum technique of frequency hopping work?

Select	Answer
A	A binary bit stream is used to shift the phase of an RF carrier very rapidly in a pseudorandom sequence
B	If interference is detected by the receiver it will signal the transmitter to change frequencies
C	The frequency of the transmitted signal is changed very rapidly according to a pseudorandom sequence also used by the receiving station
D	If interference is detected by the receiver it will signal the transmitter to wait until the frequency is clear

43. - E9A03

What is the radiation resistance of an antenna?

Select	Answer
A	The specific impedance of the antenna
B	The resistance in the atmosphere that an antenna must overcome to be able to radiate a signal
C	The value of a resistance that would dissipate the same amount of power as that radiated from an antenna
D	The combined losses of the antenna elements and feed line

44. - E9B02

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

Select	Answer
A	24 dB
B	18 dB
C	36 dB
D	14 dB

45. - E9C01

What is the radiation pattern of two 1/4-wavelength vertical antennas spaced 1/2-wavelength apart and fed 180 degrees out of phase?

Select	Answer
A	A figure-8 broadside to the axis of the array
B	Cardioid
C	A figure-8 oriented along the axis of the array
D	Omni-directional

46. - E9D09

What is the function of a loading coil used as part of an HF mobile antenna?

Select	Answer
A	To lower the losses
B	To cancel capacitive reactance
C	To lower the Q
D	To increase the SWR bandwidth

47. - E9E11

What is the primary purpose of phasing lines when used with an antenna having multiple driven elements?

Select	Answer
A	It ensures that each driven element operates in concert with the others to create the desired antenna pattern
B	It creates a low-angle radiation pattern
C	It allows single-band antennas to operate on other bands
D	It prevents reflected power from traveling back down the feed line and causing harmonic radiation from the transmitter

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	7.0 meters
B	10.6 meters
C	13.3 meters
D	8.5 meters

49. - E9G03

Which of the following is often determined using a Smith chart?

Select	Answer
A	Impedance and SWR values in transmission lines
B	Satellite azimuth and elevation bearings
C	Beam headings and radiation patterns
D	Trigonometric functions

50. - E9H05

What is the main drawback of a small wire-loop antenna for direction finding?

Select	Answer
A	All these choices are correct
B	It is practical for use only on VHF and higher bands
C	It has a bidirectional pattern
D	It has no clearly defined null

Figure E7-1

Figure E9-1