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

2. - E1A13

Who must be in physical control of the station apparatus of an amateur station aboard any vessel or craft that is documented or registered in the United States?

Select	Answer
A	Any person named in an amateur station license grant or a person holding an unrestricted Radiotelephone Operator Permit
B	Only a person with an FCC Marine Radio license grant
C	Any person holding an FCC issued amateur license or who is authorized for alien reciprocal operation
D	Only a person named in an amateur station license grant

3. - E1B03

Within what distance must an amateur station protect an FCC monitoring facility from harmful interference?

Select	Answer
A	30 miles
B	3 miles
C	1 mile
D	10 miles

4. - E1C01

What is the maximum bandwidth for a data emission on 60 meters?

Select	Answer
A	170 Hz
B	1.5 kHz
C	2.8 kHz
D	60 Hz

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

6. - E1E03

What is a Volunteer Examiner Coordinator?

Select	Answer
A	The person who has entered into an agreement with the FCC to be the VE session manager
B	A person who has volunteered to administer amateur operator license examinations
C	An organization that has entered into an agreement with the FCC to coordinate, prepare, and administer amateur operator license examinations
D	A person who has volunteered to prepare amateur operator license examinations

7. - E1F09

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

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

8. - E2A09

What do the terms L band and S band specify regarding satellite communications?

Select	Answer
A	FM and Digital Store-and-Forward systems
B	Which sideband to use
C	The 2 meter and 70 centimeter bands
D	The 23 centimeter and 13 centimeter bands

9. - E2B01

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

Select	Answer
A	60
B	120
C	30
D	90

10. - E2C05

What is the function of a DX QSL Manager?

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

11. - E2D04

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

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

12. - E2E08

Which of the following HF digital modes can be used to transfer binary files?

Select	Answer
A	AMTOR
B	Hellschreiber
C	PACTOR
D	RTTY

13. - E3A05

Tropospheric propagation of microwave signals often occurs in association with what phenomenon?

Select	Answer
A	Grayline
B	Warm and cold fronts
C	Lightning discharges
D	Sprites and jets

14. - E3B09

At what time of year is sporadic E propagation most likely to occur?

Select	Answer
A	Around the equinoxes, especially the fall equinox
B	Around the solstices, especially the winter solstice
C	Around the equinoxes, especially the spring equinox
D	Around the solstices, especially the summer solstice

15. - E3C14

Why does the radio-path horizon distance exceed the geometric horizon?

Select	Answer
A	Downward bending due to density variations in the atmosphere
B	Due to the Doppler effect
C	D-region skip
D	E-region skip

16. - E4A09

Which of the following is good practice when using an oscilloscope probe?

Select	Answer
A	Keep the signal ground connection of the probe as short as possible
B	All these choices are correct
C	Never use a high-impedance probe to measure a low-impedance circuit
D	Never use a DC-coupled probe to measure an AC circuit

17. - E4B07

What do the subscripts of S parameters represent?

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

18. - E4C06

A CW receiver with the AGC off has an equivalent input noise power density of -174 dBm/Hz. What would be the level of an unmodulated carrier input to this receiver that would yield an audio output SNR of 0 dB in a 400 Hz noise bandwidth?

Select	Answer
A	-174 dBm
B	-164 dBm
C	-155 dBm
D	-148 dBm

19. - E4D09

What is the purpose of the preselector in a communications receiver?

Select	Answer
A	To store often-used frequencies
B	To allow selection of the optimum RF amplifier device
C	To increase rejection of signals outside the desired band
D	To provide a range of AGC time constants

20. - E4E09

What undesirable effect can occur when using an IF noise blanker?

Select	Answer
A	FM signals can no longer be demodulated
B	Nearby signals may appear to be excessively wide even if they meet emission standards
C	Received audio in the speech range might have an echo effect
D	The audio frequency bandwidth of the received signal might be compressed

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

22. - E5B08

What is the phase angle between the voltage across and the current through a series RLC circuit if XC is 100 ohms, R is 100 ohms, and XL is 75 ohms?

Select	Answer
A	14 degrees with the voltage leading the current
B	76 degrees with the voltage lagging the current
C	14 degrees with the voltage lagging the current
D	76 degrees with the voltage leading the current

23. - E5C10

Which point on Figure E5-1 best represents the impedance of a series circuit consisting of a 400-ohm resistor and a 38-picofarad capacitor at 14 MHz?

Select	Answer
A	Point 6
B	Point 2
C	Point 4
D	Point 5

24. - E5D15

What is the power factor of an RL circuit having a 45-degree phase angle between the voltage and the current?

Select	Answer
A	0.5
B	0.707
C	0.866
D	1.0

25. - E6A09

What is a depletion-mode FET?

Select	Answer
A	An FET that exhibits a current flow between source and drain when no gate voltage is applied
B	Any FET for which holes are the majority carriers
C	Any FET without a channel
D	An FET that has no current flow between source and drain when no gate voltage is applied

26. - E6B08

Which of the following is a Schottky barrier diode?

Select	Answer
A	Electrolytic rectifier
B	PIN junction
C	Metal-semiconductor junction
D	Thermionic emission diode

27. - E6C03

What is tri-state logic?

Select	Answer
A	Logic devices with 0, 1, and high-impedance output states
B	Logic devices that utilize ternary math
C	Proprietary logic devices manufactured by Tri-State Devices
D	Low-power logic devices designed to operate at 3 volts

28. - E6D12

What is inductor saturation?

Select	Answer
A	The ability of the inductor's core to store magnetic energy has been exceeded
B	Adjacent inductors become over-coupled
C	The inductor's voltage rating is exceeded causing a flashover
D	The inductor windings are over-coupled

29. - E6E11

What is a characteristic of DIP packaging used for integrated circuits?

Select	Answer
A	A total of two rows of connecting pins placed on opposite sides of the package (Dual In-line Package)
B	Low leakage doubly insulated package
C	Package mounts in a direct inverted position
D	Two chips in each package (Dual In Package)

30. - E6F06

Which of these materials is most commonly used to create photoconductive devices?

Select	Answer
A	A liquid semiconductor
B	A heavy metal
C	An ordinary metal
D	A crystalline semiconductor

31. - E7A01

Which circuit is bistable?

Select	Answer
A	An OR gate
B	A bipolar amplifier
C	An AND gate
D	A flip-flop

32. - E7B13

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

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

33. - E7C07

Which describes a Pi-L-network used for matching a vacuum tube final amplifier to a 50-ohm unbalanced output?

Select	Answer
A	A Pi-network with an additional series inductor on the output
B	A Phase Inverter Load network
C	A matching network in which all components are isolated from ground
D	A network with only three discrete parts

34. - E7D03

What device is typically used as a stable voltage reference in a linear voltage regulator?

Select	Answer
A	A Zener diode
B	A varactor diode
C	A tunnel diode
D	An SCR

35. - E7E11

Which type of detector circuit is used for demodulating SSB signals?

Select	Answer
A	Phase detector
B	Phase comparator
C	Discriminator
D	Product detector

36. - E7F14

Which of the following would allow a digital signal processing filter to create a sharper filter response?

Select	Answer
A	Complex phasor representations
B	Double-precision math routines
C	Higher data rate
D	More taps

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 decreases logarithmically with increasing frequency
C	It decreases linearly with increasing frequency
D	It does not vary with frequency

38. - E7H07

How can an oscillator's microphonic responses be reduced?

Select	Answer
A	Increase the bias voltage
B	Reduce noise on the oscillator's power supply
C	Mechanically isolate the oscillator circuitry from its enclosure
D	Use NP0 capacitors

39. - E8A05

What of the following instruments would be the most accurate for measuring the RMS voltage of a complex waveform?

Select	Answer
A	A grid dip meter
B	An absorption wave meter
C	A D'Arsonval meter
D	A true-RMS calculating meter

40. - E8B08

What describes Orthogonal Frequency Division Multiplexing?

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

41. - E8C07

What is the bandwidth of a 4800-Hz frequency shift, 9600-baud ASCII FM transmission?

Select	Answer
A	15.36 kHz
B	9.6 kHz
C	4.8 kHz
D	5.76 kHz

42. - E8D04

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

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

43. - E9A01

What is an isotropic antenna?

Select	Answer
A	A horizontally polarized antenna used to compare Yagi antennas
B	A theoretical, omnidirectional antenna used as a reference for antenna gain
C	A spacecraft antenna used to direct signals toward Earth
D	A grounded antenna used to measure Earth conductivity

44. - E9B08

What is the far field of an antenna?

Select	Answer
A	The region where radiated field strengths are constant
B	The region where the shape of the antenna pattern is independent of distance
C	The region where radiated power dissipates over a specified time period
D	The region of the ionosphere where radiated power is not refracted

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 increases
D	The takeoff angle of the lowest elevation lobe decreases

46. - E9D05

What usually occurs if a Yagi antenna is designed solely for maximum forward gain?

Select	Answer
A	The frequency response is widened over the whole frequency band
B	The front-to-back ratio decreases
C	The front-to-back ratio increases
D	The SWR is reduced

47. - E9E10

Which of these choices is an effective way to match an antenna with a 100-ohm feed point impedance to a 50-ohm coaxial cable feed line?

Select	Answer
A	Connect a 1/2 wavelength shorted stub of 75-ohm cable in parallel with the 50-ohm cable where it attaches to the antenna
B	Insert a 1/2 wavelength piece of 300-ohm twinlead in series between the antenna terminals and the 50-ohm feed cable
C	Insert a 1/4-wavelength piece of 75-ohm coaxial cable transmission line in series between the antenna terminals and the 50-ohm feed cable
D	Connect a 1/4-wavelength open stub of 300-ohm twinlead in parallel with the coaxial feed line where it connects to the antenna

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	6.9 meters
B	5.2 meters
C	10.4 meters
D	8.3 meters

49. - E9G02

What type of coordinate system is used in a Smith chart?

Select	Answer
A	Resistance circles and reactance arcs
B	Resistance lines and reactance chords
C	Voltage circles and current arcs
D	Voltage lines and current chords

50. - E9H06

What is the triangulation method of direction finding?

Select	Answer
A	A fixed receiving station plots three headings to the signal source
B	A fixed receiving station uses three different antennas to plot the location of the signal source
C	The geometric angles of sky waves from the source are used to determine its position
D	Antenna headings from several different receiving locations are used to locate the signal source

Figure E5-1