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

2. - E1A04

With your transceiver displaying the carrier frequency of phone signals, you hear a DX station calling CQ on 3.601 MHz LSB. Is it legal to return the call using lower sideband on the same frequency?

Select	Answer
A	No, U.S. stations are not permitted to use phone emissions below 3.610 MHz
B	Yes, because the displayed frequency is within the 75 meter phone band segment
C	No, the sideband will extend beyond the edge of the phone band segment
D	Yes, because the DX station initiated the contact

3. - E1B06

Which of the following additional rules apply if you are installing an amateur station antenna at a site at or near a public use airport?

Select	Answer
A	You may have to notify the Federal Aviation Administration and register it with the FCC as required by Part 17 of the FCC rules
B	You must file an Environmental Impact Statement with the EPA before construction begins
C	You must obtain a construction permit from the airport zoning authority
D	You must submit engineering drawings to the FAA

4. - E1C05

When may an automatically controlled station originate third party communications?

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

5. - E1D09

Which UHF amateur bands have frequencies authorized for space stations?

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

6. - E1E02

Who does Part 97 task with maintaining the pools of questions for all U.S. amateur license examinations?

Select	Answer
A	The ARRL
B	The VEs
C	The FCC
D	The VECs

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

8. - E2A04

What is meant by the term mode? as applied to an amateur radio satellite?

Select	Answer
A	Whether the satellite is in a low earth or geostationary orbit
B	Whether the satellite is in a polar or equatorial orbit
C	The satellite's orientation with respect to the Earth
D	The satellite's uplink and downlink frequency bands

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	No other hardware is needed
C	A special notch filter to remove synchronization pulses
D	A special IF converter

10. - E2C10

Why might a DX station state that they are listening on another frequency?

Select	Answer
A	All these choices are correct
B	Because the DX station may be transmitting on a frequency that is prohibited to some responding stations
C	To separate the calling stations from the DX station
D	To improve operating efficiency by reducing interference

11. - E2D02

Which of the following is a good technique for making meteor scatter contacts?

Select	Answer
A	15-second timed transmission sequences with stations alternating based on location
B	All these choices are correct
C	Use of special digital modes
D	Short transmissions with rapidly repeated call signs and signal reports

12. - E2E03

How is the timing of FT4 contacts organized?

Select	Answer
A	It depends on the lunar phase
B	Alternating transmissions at 7.5 second intervals
C	By exchanging ACK/NAK packets
D	Stations take turns on alternate days

13. - E3A10

Which type of atmospheric structure can create a path for microwave propagation?

Select	Answer
A	Temperature inversion
B	The jet stream
C	Wind shear
D	Dust devil

14. - E3B04

What is meant by the terms "extraordinary" and "ordinary" waves?

Select	Answer
A	Extraordinary waves describe rare long-skip propagation compared to ordinary waves, which travel shorter distances
B	Independent waves created in the ionosphere that are elliptically polarized
C	Refracted rays and reflected waves
D	Long-path and short-path waves

15. - E3C08

What does the space weather term G5 mean?

Select	Answer
A	Very low solar activity
B	Waning sunspot numbers
C	Moderate solar wind
D	An extreme geomagnetic storm

16. - E4A08

Which of the following measures SWR?

Select	Answer
A	An ohmmeter
B	A spectrum analyzer
C	A Q meter
D	An antenna analyzer

17. - E4B03

Which S parameter is equivalent to forward gain?

Select	Answer
A	S22
B	S11
C	S21
D	S12

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

19. - E4D11

Why are odd-order intermodulation products, created within a receiver, of particular interest compared to other products?

Select	Answer
A	Odd-order products of two signals in the band of interest are also likely to be within the band
B	Odd-order products overload the IF filters
C	Odd-order intermodulation produces three products for every input signal within the band of interest
D	Odd-order products are an indication of poor image rejection

20. - E4E05

How can radio frequency interference from an AC motor be suppressed?

Select	Answer
A	By installing a high-pass filter in series with the motor's power leads
B	By using a ground-fault current interrupter in the circuit used to power the motor
C	By installing a bypass capacitor in series with the motor leads
D	By installing a brute-force AC-line filter in series with the motor leads

21. - E5A04

What is the magnitude of the impedance of a parallel RLC circuit at resonance?

Select	Answer
A	Low compared to the circuit resistance
B	Approximately equal to inductive reactance
C	Approximately equal to circuit resistance
D	High compared to the circuit resistance

22. - E5B12

What is admittance?

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

23. - E5C04

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

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

24. - E5D02

Why is it important to keep lead lengths short for components used in circuits for VHF and above?

Select	Answer
A	To maintain component lifetime
B	To increase the thermal time constant
C	To avoid unwanted inductive reactance
D	All these choices are correct

25. - E6A08

What term indicates the frequency at which the grounded-base current gain of a transistor has decreased to 0.7 of the gain obtainable at 1 kHz?

Select	Answer
A	Alpha rejection frequency
B	Alpha cutoff frequency
C	Beta cutoff frequency
D	Corner frequency

26. - E6B06

Which of the following is a common use of a Schottky diode?

Select	Answer
A	As a VHF/UHF mixer or detector
B	As a constant voltage reference in a power supply
C	As a variable capacitance in an automatic frequency control circuit
D	As a rectifier in high current power supplies

27. - E6C02

What happens when the level of a comparator's input signal crosses the threshold?

Select	Answer
A	The comparator changes its output state
B	The IC input can be damaged
C	The comparator enters latch-up
D	The feedback loop becomes unstable

28. - E6D08

What is one reason for using powdered-iron cores rather than ferrite cores in an inductor?

Select	Answer
A	Powdered-iron cores generally require fewer turns to produce a given inductance
B	Powdered-iron cores generally maintain their characteristics at higher currents
C	Powdered-iron cores use smaller diameter wire for the same inductance
D	Powdered-iron cores generally have greater initial permeability

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	Package mounts in a direct inverted position
C	Low leakage doubly insulated package
D	Two chips in each package (Dual In Package)

30. - E6F01

What absorbs the energy from light falling on a photovoltaic cell?

Select	Answer
A	Protons
B	Electrons
C	Photons
D	Holes

31. - E7A05

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

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

32. - E7B14

Why are switching amplifiers more efficient than linear amplifiers?

Select	Answer
A	The power transistor is at saturation or cutoff most of the time
B	Linear amplifiers have high gain resulting in higher harmonic content
C	Switching amplifiers use push-pull circuits
D	Switching amplifiers operate at higher voltages

33. - E7C02

Which of the following is a property of a T-network with series capacitors and a parallel shunt inductor?

Select	Answer
A	It is a notch filter
B	It is a band-pass filter
C	It is a low-pass filter
D	It is a high-pass filter

34. - E7D14

What is the purpose of connecting equal-value resistors across power supply filter capacitors connected in series?

Select	Answer
A	Discharge the capacitors when voltage is removed
B	All these choices are correct
C	Equalize the voltage across each capacitor
D	Provide a minimum load on the supply

35. - E7E05

What circuit is added to an FM transmitter to boost the higher audio frequencies?

Select	Answer
A	A de-emphasis network
B	A heterodyne suppressor
C	A heterodyne enhancer
D	A pre-emphasis network

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 can delay all frequency components of the signal by the same amount
C	FIR filters can respond faster to impulses
D	FIR filters are easier to implement for a given set of passband rolloff requirements

37. - E7G06

What is the gain-bandwidth of an operational amplifier?

Select	Answer
A	The gain of the amplifier at a filter's cutoff frequency
B	The maximum frequency for a filter circuit using that type of amplifier
C	The frequency at which the open-loop gain of the amplifier equals one
D	The frequency at which the amplifier's offset voltage is zero

38. - E7H06

Which of the following oscillator circuits are commonly used in VFOs?

Select	Answer
A	Pierce and Zener
B	Negative feedback and balanced feedback
C	Colpitts and Hartley
D	Armstrong and deForest

39. - E8A03

What type of wave does a Fourier analysis show to be made up of sine waves of a given fundamental frequency plus all its harmonics?

Select	Answer
A	A sawtooth wave
B	A cosine wave
C	A square wave
D	A sine wave

40. - E8B10

What is frequency division multiplexing?

Select	Answer
A	The transmitted signal is divided into packets of information
B	Two or more information streams are merged into a digital combiner, which then pulse position modulates the transmitter
C	The transmitted signal jumps from band to band at a predetermined rate
D	Two or more information streams are merged into a baseband, which then modulates the transmitter

41. - E8C04

What technique minimizes the bandwidth of a PSK31 signal?

Select	Answer
A	Use of trapezoidal data pulses
B	Reed-Solomon character encoding
C	Use of sinusoidal data pulses
D	Zero-sum character encoding

42. - E8D10

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

Select	Answer
A	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
B	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
C	Baudot uses 7 data bits per character, ASCII uses 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. - E9A09

What is antenna efficiency?

Select	Answer
A	Radiation resistance divided by transmission resistance
B	Radiation resistance divided by total resistance
C	Effective radiated power divided by transmitter output
D	Total resistance divided by radiation resistance

44. - E9B06

What is the elevation angle of peak response in the antenna radiation pattern shown in Figure E9-2?

Select	Answer
A	45 degrees
B	7.5 degrees
C	25 degrees
D	75 degrees

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

46. - E9D03

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

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

47. - E9E08

What is a use for a Wilkinson divider?

Select	Answer
A	It is used to divide power equally between two 50-ohm loads while maintaining 50-ohm input impedance
B	It is used to feed low-impedance loads from a high-impedance source
C	It divides the operating frequency of a transmitter signal so it can be used on a lower frequency band
D	It is used to feed high-impedance antennas from a low-impedance source

48. - E9F10

What impedance does a 1/8-wavelength transmission line present to a generator when the line is shorted at the far end?

Select	Answer
A	The same as the characteristic impedance of the line
B	Zero
C	A capacitive reactance
D	An inductive reactance

49. - E9G06

On the Smith chart shown in Figure E9-3, what is the name for the large outer circle on which the reactance arcs terminate?

Select	Answer
A	Reactance axis
B	Prime axis
C	Impedance axis
D	Polar axis

50. - E9H07

Why is RF attenuation used when direction-finding?

Select	Answer
A	To prevent receiver overload which reduces pattern nulls
B	To increase receiver sensitivity
C	To narrow the receiver bandwidth
D	To compensate for isotropic directivity and the antenna effect of feed lines

Figure E9-2

Figure E9-3