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

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1. - E0A10

What toxic material may be present in some electronic components such as high voltage capacitors and transformers?

Select	Answer
A	Polyethylene
B	Polytetrafluoroethylene
C	Polymorphic silicon
D	Polychlorinated biphenyls

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	18.100 MHz
B	18.110 MHz
C	18.068 MHz
D	18.107 MHz

3. - E1B05

What is the National Radio Quiet Zone?

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

4. - E1C05

When may an automatically controlled station originate third party communications?

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

5. - E1D04

Which of the following is required in the identification transmissions from a balloon-borne telemetry station?

Select	Answer
A	All these choices are correct
B	The output power of the balloon transmitter
C	The station's six-character Maidenhead grid locator
D	Call sign

6. - E1E07

What should a VE do if a candidate fails to comply with the examiner's instructions during an amateur operator license examination?

Select	Answer
A	Warn the candidate that continued failure to comply will result in termination of the examination
B	Immediately terminate the candidate's examination
C	Immediately terminate everyone's examination and close the session
D	Allow the candidate to complete the examination, but invalidate the results

7. - E1F02

What privileges are authorized in the U.S. to persons holding an amateur service license granted by the government of Canada?

Select	Answer
A	All privileges of the Amateur Extra Class license
B	The operating terms and conditions of the Canadian amateur service license, not to exceed U.S. Amateur Extra Class license privileges
C	None, they must obtain a U.S. license
D	Full privileges, up to and including those of the Amateur Extra Class license, on the 80, 40, 20, 15, and 10 meter bands

8. - E2A01

What is the direction of an ascending pass for an amateur satellite?

Select	Answer
A	From north to south
B	From east to west
C	From west to east
D	From south to north

9. - E2B07

What is the name of the signal component that carries color information in NTSC video?

Select	Answer
A	Luminance
B	Hue
C	Chroma
D	Spectral intensity

10. - E2C06

During a VHF/UHF contest, in which band segment would you expect to find the highest level of SSB or CW activity?

Select	Answer
A	In the weak signal segment of the band, with most of the activity near the calling frequency
B	At the top of each band, usually in a segment reserved for contests
C	In the middle of the band, usually 25 kHz above the national calling frequency
D	In the middle of each band, usually on the national calling frequency

11. - E2D05

What is one advantage of the JT65 mode?

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

12. - E2E01

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

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

13. - E3A11

What is a typical range for tropospheric propagation of microwave signals?

Select	Answer
A	100 miles to 300 miles
B	2500 miles
C	10 miles to 50 miles
D	1200 miles

14. - E3B06

Which of the following amateur bands most frequently provides long-path propagation?

Select	Answer
A	80 meters
B	6 meters
C	10 meters
D	20 meters

15. - E3C07

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

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

16. - E4A04

How is the compensation of an oscilloscope probe typically adjusted?

Select	Answer
A	A frequency standard is displayed and the probe is adjusted until the deflection time is accurate
B	A square wave is displayed and the probe is adjusted until the horizontal portions of the displayed wave are as nearly flat as possible
C	A high frequency sine wave is displayed and the probe is adjusted for maximum amplitude
D	A DC voltage standard is displayed and the probe is adjusted until the displayed voltage is accurate

17. - E4B10

Which of the following methods measures intermodulation distortion in an SSB transmitter?

Select	Answer
A	Modulate the transmitter using two AF signals having harmonically related frequencies and observe the RF output with a peak reading wattmeter
B	Modulate the transmitter using two AF signals having non-harmonically related frequencies and observe the RF output with a spectrum analyzer
C	Modulate the transmitter using two RF signals having non-harmonically related frequencies and observe the RF output with a spectrum analyzer
D	Modulate the transmitter using two RF signals having harmonically related frequencies and observe the RF output with a logic analyzer

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

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

20. - E4E07

Which of the following can cause shielded cables to radiate or receive interference?

Select	Answer
A	Tying all ground connections to a common point resulting in differential-mode currents in the shield
B	Low inductance ground connections at both ends of the shield
C	Use of braided shielding material
D	Common-mode currents on the shield and conductors

21. - E5A15

Which of the following increases Q for inductors and capacitors?

Select	Answer
A	Lower losses
B	Higher self-resonant frequency
C	Lower self-resonant frequency
D	Lower reactance

22. - E5B10

What is the relationship between the AC current through an inductor and the voltage across an inductor?

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

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 5
B	Point 4
C	Point 6
D	Point 2

24. - E5D01

What is the result of skin effect?

Select	Answer
A	Thermal effects on the surface of the conductor decrease the impedance
B	Thermal effects on the surface of the conductor increase the impedance
C	As frequency increases, RF current flows in a thinner layer of the conductor, closer to the surface
D	As frequency decreases, RF current flows in a thinner layer of the conductor, closer to the surface

25. - E6A11

In Figure E6-1, what is the schematic symbol for a P-channel junction FET?

Select	Answer
A	2
B	6
C	1
D	3

26. - E6B03

What type of bias is required for an LED to emit light?

Select	Answer
A	Inductive bias
B	Forward bias
C	Reverse bias
D	Zero bias

27. - E6C03

What is tri-state logic?

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

28. - E6D13

What is the primary cause of inductor self-resonance?

Select	Answer
A	Inductive kickback
B	The skin effect
C	Non-linear core hysteresis
D	Inter-turn capacitance

29. - E6E05

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

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

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 impedance matching between the control circuit and power circuit
D	Optoisolators provide a low impedance link between a control circuit and a power circuit

31. - E7A04

How many flip-flops are required to divide a signal frequency by 4?

Select	Answer
A	1
B	4
C	8
D	2

32. - E7B05

What can be done to prevent unwanted oscillations in an RF power amplifier?

Select	Answer
A	Use a phase inverter in the output filter
B	Tune the stage for maximum SWR
C	Tune both the input and output for maximum power
D	Install parasitic suppressors and/or neutralize the stage

33. - E7C04

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

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

34. - E7D03

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

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

35. - E7E07

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

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

36. - E7F03

What type of digital signal processing filter is used to generate an SSB signal?

Select	Answer
A	An elliptical filter
B	A Hilbert-transform filter
C	A notch filter
D	An adaptive filter

37. - E7G07

What magnitude of voltage gain can be expected from the circuit in Figure E73 when R1 is 10 ohms and RF is 470 ohms?

Select	Answer
A	94
B	47
C	24
D	0.21

38. - E7H15

Which of these functions can be performed by a phase-locked loop?

Select	Answer
A	Wide-band AF and RF power amplification
B	Frequency synthesis, FM demodulation
C	Comparison of two digital input signals, digital pulse counter
D	Photovoltaic conversion, optical coupling

39. - E8A10

What is the purpose of a low-pass filter used in conjunction with a digital-to-analog converter?

Select	Answer
A	Remove harmonics from the output caused by the discrete analog levels generated
B	Improve accuracy by removing out-of-sequence codes from the input
C	Lower the input bandwidth to increase the effective resolution
D	All these choices are correct

40. - E8B01

What is the modulation index of an FM signal?

Select	Answer
A	The type of modulation used by the transmitter
B	The ratio of modulating signal amplitude to frequency deviation
C	The bandwidth of the transmitted signal divided by the modulating signal frequency
D	The ratio of frequency deviation to modulating signal frequency

41. - E8C09

Which digital code allows only one bit to change between sequential code values?

Select	Answer
A	Extended Binary Coded Decimal Interchange Code
B	Excess 3 code
C	Gray code
D	Binary Coded Decimal Code

42. - E8D06

What is the advantage of including parity bits in ASCII characters?

Select	Answer
A	The signal can overpower interfering signals
B	Some types of errors can be detected
C	Foreign language characters can be sent
D	Faster transmission rate

43. - E9A01

What is an isotropic antenna?

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

44. - E9B11

What is a disadvantage of decreasing the number of wire segments in an antenna model below 10 segments per half-wavelength?

Select	Answer
A	Ground conductivity will not be accurately modeled
B	The resulting design will favor radiation of harmonic energy
C	The computed feed point impedance may be incorrect
D	The antenna will become mechanically unstable

45. - E9C09

Which of the following describes a G5RV antenna?

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

46. - E9D03

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

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

47. - E9E01

What system matches a higher-impedance transmission line to a lower-impedance antenna by connecting the line to the driven element in two places spaced a fraction of a wavelength each side of element center?

Select	Answer
A	The delta matching system
B	The gamma matching system
C	The omega matching system
D	The stub matching system

48. - E9F03

Why is the physical length of a coaxial cable transmission line shorter than its electrical length?

Select	Answer
A	Skin effect is less pronounced in the coaxial cable
B	Electrical signals move more slowly in a coaxial cable than in air
C	The characteristic impedance is higher in a parallel feed line
D	The surge impedance is higher in a parallel feed line

49. - E9G02

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

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

50. - E9H03

What is Receiving Directivity Factor (RDF)?

Select	Answer
A	Forward gain compared to the gain in the reverse direction
B	Relative directivity compared to a dipole
C	Relative directivity compared to isotropic
D	Forward gain compared to average gain over the entire hemisphere

Figure E5-1

Figure E6-1