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 to 3000 MHz
B	3 to 30 MHz
C	30 to 300 MHz
D	300 kHz to 3 MHz

2. - E1A06

Where must the carrier frequency of a CW signal be set to comply with FCC rules for 60 meter operation?

Select	Answer
A	At the lowest frequency of the channel
B	On any frequency where the signal's sidebands are within the channel
C	At the highest frequency of the channel
D	At the center frequency of the channel

3. - E1B02

Which of the following is an acceptable bandwidth for Digital Radio Mondiale (DRM) based voice or SSTV digital transmissions made on the HF amateur bands?

Select	Answer
A	3 kHz
B	10 kHz
C	15 kHz
D	20 kHz

4. - E1C04

What is meant by IARP?

Select	Answer
A	A forecast of intermittent aurora radio propagation
B	An international amateur radio permit that allows U.S. amateurs to operate in certain countries of the Americas
C	The internal amateur radio practices policy of the FCC
D	An indication of increased antenna reflected power

5. - E1D09

Which UHF amateur bands have frequencies authorized for space stations?

Select	Answer
A	70 cm and 33 cm
B	70 cm only
C	33 cm and 13 cm
D	70 cm and 13 cm

6. - E1E10

What must the administering VEs do after the administration of a successful examination for an amateur operator license?

Select	Answer
A	They must collect and send the documents to the NCVEC for grading
B	They must submit the application document to the coordinating VEC according to the coordinating VEC instructions
C	They must collect and send the documents to the FCC according to instructions
D	They must collect and submit the documents to the coordinating VEC for grading

7. - E1F05

Amateur stations may not transmit in which of the following frequency segments if they are located in the contiguous 48 states and north of Line A?

Select	Answer
A	222 MHz - 223 MHz
B	420 MHz - 430 MHz
C	440 MHz - 450 MHz
D	53 MHz - 54 MHz

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 passed through a mixer and the difference rather than the sum is transmitted
C	The signal is detected and remodulated on the reverse sideband
D	The signal is reduced to I and Q components and the Q component is filtered out

9. - E2B06

What is vestigial sideband modulation?

Select	Answer
A	Narrow-band FM modulation achieved by filtering one sideband from the audio before frequency modulating the carrier
B	Amplitude modulation in which one complete sideband and a portion of the other are transmitted
C	A type of modulation in which one sideband is inverted
D	Spread spectrum modulation achieved by applying FM modulation following single sideband amplitude modulation

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. - E2D08

What type of packet frame is used to transmit APRS beacon data?

Select	Answer
A	Connect
B	Acknowledgement
C	Disconnect
D	Unnumbered Information

12. - E2E02

What do the letters FEC mean as they relate to digital operation?

Select	Answer
A	First Error Correction
B	Forward Error Correction
C	Final Error Correction
D	Fatal Error Correction

13. - E3A04

What do Hepburn maps predict?

Select	Answer
A	Sporadic E propagation
B	Likelihood of rain scatter along cold or warm fronts
C	Probability of tropospheric propagation
D	Locations of auroral reflecting zones

14. - E3B02

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

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

15. - E3C13

What type of polarization is best for ground-wave propagation?

Select	Answer
A	Elliptical
B	Horizontal
C	Vertical
D	Circular

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. - E4B01

Which of the following factors most affects the accuracy of a frequency counter?

Select	Answer
A	Temperature coefficient of the logic
B	Input attenuator accuracy
C	Decade divider accuracy
D	Time base accuracy

18. - E4C12

Which of the following has the largest effect on an SDR receiver's dynamic range?

Select	Answer
A	Analog-to-digital converter sample width in bits
B	CPU register width in bits
C	Anti-aliasing input filter bandwidth
D	RAM speed used for data storage

19. - E4D03

How can intermodulation interference between two repeaters occur?

Select	Answer
A	When the repeaters are in close proximity and the signals cause feedback in the final amplifier of one or both transmitters
B	When the signals from the transmitters are reflected in phase from airplanes passing overhead
C	When the signals from the transmitters are reflected out of phase from airplanes passing overhead
D	When the repeaters are in close proximity and the signals mix in the final amplifier of one or both transmitters

20. - E4E04

How can conducted and radiated noise caused by an automobile alternator be suppressed?

Select	Answer
A	By installing a noise suppression resistor and a blocking capacitor in both leads
B	By installing filter capacitors in series with the DC power lead and a blocking capacitor in the field lead
C	By installing a high-pass filter in series with the radio's power lead and a low-pass filter in parallel with the field lead
D	By connecting the radio's power leads directly to the battery and by installing coaxial capacitors in line with the alternator leads

21. - E5A02

What is resonance in an LC or RLC circuit?

Select	Answer
A	The highest frequency that will pass current
B	The frequency at which the capacitive reactance equals the inductive reactance
C	The frequency at which the reactive impedance equals the resistive impedance
D	The lowest frequency that will pass current

22. - E5B02

What letter is commonly used to represent susceptance?

Select	Answer
A	G
B	Y
C	B
D	X

23. - E5C04

What coordinate system is often used to display the resistive, inductive, and/or capacitive reactance components of impedance?

Select	Answer
A	Maidenhead grid
B	Rectangular coordinates
C	Elliptical coordinates
D	Faraday grid

24. - E5D03

What is microstrip?

Select	Answer
A	Precision printed circuit conductors above a ground plane that provide constant impedance interconnects at microwave frequencies
B	Lightweight transmission line made of common zip cord
C	Short lengths of coax mounted on printed circuit boards to minimize time delay between microwave circuits
D	Miniature coax used for low power applications

25. - E6A10

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

Select	Answer
A	4
B	2
C	5
D	6

26. - E6B11

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

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

27. - E6C03

What is tri-state logic?

Select	Answer
A	Logic devices that utilize ternary math
B	Proprietary logic devices manufactured by Tri-State Devices
C	Low-power logic devices designed to operate at 3 volts
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	Non-linear core hysteresis
B	Inter-turn capacitance
C	Inductive kickback
D	The skin effect

29. - E6E12

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

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

30. - E6F08

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

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

31. - E7A03

Which of the following can divide the frequency of a pulse train by 2?

Select	Answer
A	An OR gate
B	A flip-flop
C	A multiplexer
D	An XOR gate

32. - E7B02

What is a Class D amplifier?

Select	Answer
A	An amplifier that uses drift-mode FETs for high efficiency
B	A type of amplifier that uses switching technology to achieve high efficiency
C	A frequency doubling amplifier
D	A low power amplifier that uses a differential amplifier for improved linearity

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 sharp cutoff with one or more notches in the stop band
D	Extremely flat response over its pass band with gradually rounded stop band corners

34. - E7D01

How does a linear electronic voltage regulator work?

Select	Answer
A	The conduction of a control element is varied to maintain a constant output voltage
B	It has a ramp voltage as its output
C	It eliminates the need for a pass transistor
D	The control element duty cycle is proportional to the line or load conditions

35. - E7E04

What is one way a single-sideband phone signal can be generated?

Select	Answer
A	By driving a product detector with a DSB signal
B	By using a balanced modulator followed by a filter
C	By using a loop modulator followed by a mixer
D	By using a reactance modulator followed by a mixer

36. - E7F12

Which of the following is an advantage of a Finite Impulse Response (FIR) filter vs an Infinite Impulse Response (IIR) digital filter?

Select	Answer
A	All these choices are correct
B	FIR filters are easier to implement for a given set of passband rolloff requirements
C	FIR filters can delay all frequency components of the signal by the same amount
D	FIR filters can respond faster to impulses

37. - E7G03

What is the typical input impedance of an op-amp?

Select	Answer
A	1000 ohms
B	Very high
C	100 ohms
D	Very low

38. - E7H11

What are the major spectral impurity components of direct digital synthesizers?

Select	Answer
A	Broadband noise
B	Spurious signals at discrete frequencies
C	Digital conversion noise
D	Nyquist limit noise

39. - E8A08

Why would a direct or flash conversion analog-to-digital converter be useful for a software defined radio?

Select	Answer
A	Immunity to out-of-sequence coding reduces spurious responses
B	Very high speed allows digitizing high frequencies
C	All these choices are correct
D	Very low power consumption decreases frequency drift

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 frequency modulation technique that uses non-harmonically related frequencies
C	A bandwidth compression technique using Fourier transforms
D	A digital mode for narrow-band, slow-speed transmissions

41. - E8C12

What factors affect the bandwidth of a transmitted CW signal?

Select	Answer
A	Keying speed and shape factor (rise and fall time)
B	All these choices are correct
C	Modulation index and output power
D	IF bandwidth and Q

42. - E8D11

What is one advantage of using ASCII code for data communications?

Select	Answer
A	It is possible to transmit both upper and lower case text
B	It contains fewer information bits per character than any other code
C	It uses one character as a shift code to send numeric and special characters
D	It includes built-in error correction features

43. - E9A01

What is an isotropic antenna?

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

44. - E9B07

How does the total amount of radiation emitted by a directional gain antenna compare with the total amount of radiation emitted from a theoretical isotropic antenna, assuming each is driven by the same amount of power?

Select	Answer
A	The total amount of radiation from the directional antenna is stronger by its front-to-back ratio
B	The radiation from the isotropic antenna is 2.15 dB stronger than that from the directional antenna
C	They are the same
D	The total amount of radiation from the directional antenna is increased by the gain of the antenna

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 decreases
D	The takeoff angle of the lowest elevation lobe increases

46. - E9D07

What is an advantage of using top loading in a shortened HF vertical antenna?

Select	Answer
A	Higher losses
B	Greater structural strength
C	Improved radiation efficiency
D	Lower Q

47. - E9E09

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

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

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	The characteristic impedance is higher in a parallel feed line
C	Electrical signals move more slowly in a coaxial cable than in air
D	The surge impedance is higher in a parallel feed line

49. - E9G03

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

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

50. - E9H02

Which is generally true for low band (160 meter and 80 meter) receiving antennas?

Select	Answer
A	They must be erected at least 1/2 wavelength above the ground to attain good directivity
B	All these choices are correct
C	Atmospheric noise is so high that gain over a dipole is not important
D	Low loss coax transmission line is essential for good performance

Figure E6-1