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

2. - E1A09

What action or actions should you take if your digital message forwarding station inadvertently forwards a communication that violates FCC rules?

Select	Answer
A	Discontinue forwarding the communication as soon as you become aware of it
B	Notify the nearest FCC Field Engineers office
C	Notify the originating station that the communication does not comply with FCC rules
D	All these choices are correct

3. - E1B01

Which of the following constitutes a spurious emission?

Select	Answer
A	An amateur station transmission made without the proper call sign identification
B	A signal transmitted to prevent its detection by any station other than the intended recipient
C	Any transmitted signal that unintentionally interferes with another licensed radio station
D	An emission outside the signal's necessary bandwidth that can be reduced or eliminated without affecting the information transmitted

4. - E1C13

What notifications must be given before transmitting on the 630 meter or 2200 meter bands?

Select	Answer
A	A special endorsement must be requested from the FCC
B	Operators must inform the FAA of their intent to operate, giving their call sign and distance to the nearest runway
C	An environmental impact statement must be filed with the Department of the Interior
D	Operators must inform the Utilities Technology Council (UTC) of their call sign and coordinates of the station

5. - E1D04

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

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

6. - E1E03

What is a Volunteer Examiner Coordinator?

Select	Answer
A	A person who has volunteered to prepare amateur operator license examinations
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	The person who has entered into an agreement with the FCC to be the VE session manager

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

8. - E2A12

What is the purpose of digital store-and-forward functions on an amateur radio satellite?

Select	Answer
A	To upload operational software for the transponder
B	To delay download of telemetry between satellites
C	To relay messages between satellites
D	To store digital messages in the satellite for later download by other stations

9. - E2B05

Which of the following describes the use of vestigial sideband in analog fast-scan TV transmissions?

Select	Answer
A	The vestigial sideband contains chroma information
B	Vestigial sideband reduces bandwidth while allowing for simple video detector circuitry
C	Vestigial sideband provides high frequency emphasis to sharpen the picture
D	The vestigial sideband carries the audio information

10. - E2C07

What is the Cabrillo format?

Select	Answer
A	A standard for submission of electronic contest logs
B	A method of exchanging information during a contest QSO
C	The most common set of contest rules
D	The rules of order for meetings between contest sponsors

11. - E2D10

How can an APRS station be used to help support a public service communications activity?

Select	Answer
A	An APRS station with a Global Positioning System unit can automatically transmit information to show a mobile station's position during the event
B	All these choices are correct
C	An APRS station with an emergency medical technician can automatically transmit medical data to the nearest hospital
D	APRS stations with General Personnel Scanners can automatically relay the participant numbers and time as they pass the check points

12. - E2E01

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

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

13. - E3A05

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

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

14. - E3B04

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

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

15. - E3C10

What does the 304A solar parameter measure?

Select	Answer
A	The ratio of x-ray flux to radio flux, correlated to sunspot number
B	UV emissions at 304 angstroms, correlated to the solar flux index
C	The solar wind velocity at 304 degrees from the solar equator, correlated to solar activity
D	The solar emission at 304 GHz, correlated to x-ray flare levels

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

17. - E4B07

What do the subscripts of S parameters represent?

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

18. - E4C01

What is an effect of excessive phase noise in a receiver's local oscillator?

Select	Answer
A	It decreases receiver third-order intercept point
B	It limits the receiver's ability to receive strong signals
C	It can affect the receiver's frequency calibration
D	It can combine with strong signals on nearby frequencies to generate interference

19. - E4D10

What does a third-order intercept level of 40 dBm mean with respect to receiver performance?

Select	Answer
A	The receiver can tolerate signals up to 40 dB above the noise floor without producing third-order intermodulation products
B	A pair of 40 dBm input signals will theoretically generate a third-order intermodulation product that has the same output amplitude as either of the input signals
C	A pair of 1 mW input signals will produce a third-order intermodulation product that is 40 dB stronger than the input signal
D	Signals less than 40 dBm will not generate audible third-order intermodulation products

20. - E4E02

Which of the following types of noise can often be reduced with a digital signal processing noise filter?

Select	Answer
A	Power line noise
B	Ignition noise
C	Broadband white noise
D	All these choices are correct

21. - E5A12

What is the half-power bandwidth of a resonant circuit that has a resonant frequency of 3.7 MHz and a Q of 118?

Select	Answer
A	436.6 kHz
B	15.7 kHz
C	31.4 kHz
D	218.3 kHz

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

23. - E5C05

What is the name of the diagram used to show the phase relationship between impedances at a given frequency?

Select	Answer
A	Venn diagram
B	Far field diagram
C	Near field diagram
D	Phasor diagram

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	400 watts
B	80 watts
C	2000 watts
D	50 watts

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	Corner frequency
B	Alpha cutoff frequency
C	Beta cutoff frequency
D	Alpha rejection frequency

26. - E6B04

What type of semiconductor device is designed for use as a voltage-controlled capacitor?

Select	Answer
A	Varactor diode
B	Zener diode
C	Tunnel diode
D	Silicon-controlled rectifier

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 increase the sensitivity
D	To cause the output to change states continually

28. - E6D02

What is the equivalent circuit of a quartz crystal?

Select	Answer
A	Motional capacitance, motional inductance, and loss resistance in series, all in parallel with a shunt capacitor representing electrode and stray capacitance
B	Motional capacitance, motional inductance, loss resistance, and a capacitor representing electrode and stray capacitance all in parallel
C	Motional capacitance, motional inductance, loss resistance, and a capacitor representing electrode and stray capacitance all in series
D	Motional inductance and loss resistance in series, paralleled with motional capacitance and a capacitor representing electrode and stray capacitance

29. - E6E01

Why is gallium arsenide (GaAs) useful for semiconductor devices operating at UHF and higher frequencies?

Select	Answer
A	Lower transconductance
B	Lower junction voltage drop
C	Higher noise figures
D	Higher electron mobility

30. - E6F09

What is the efficiency of a photovoltaic cell?

Select	Answer
A	The open-circuit voltage divided by the short-circuit current under full illumination
B	The output RF power divided by the input DC power
C	Cost per kilowatt-hour generated
D	The relative fraction of light that is converted to current

31. - E7A05

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

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

32. - E7B15

What is one way to prevent thermal runaway in a bipolar transistor amplifier?

Select	Answer
A	Select transistors with high beta
B	All these choices are correct
C	Neutralization
D	Use a resistor in series with the emitter

33. - E7C05

Which filter type is described as having ripple in the passband and a sharp cutoff?

Select	Answer
A	A passive op-amp filter
B	A Chebyshev filter
C	A Butterworth filter
D	An active LC filter

34. - E7D14

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

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

35. - E7E02

What is the function of a reactance modulator?

Select	Answer
A	To produce PM signals by using an electrically variable resistance
B	To produce PM or FM signals by using an electrically variable inductance or capacitance
C	To produce AM signals by using an electrically variable inductance or capacitance
D	To produce AM signals by using an electrically variable resistance

36. - E7F14

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

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

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

38. - E7H03

How is positive feedback supplied in a Hartley oscillator?

Select	Answer
A	Through a neutralizing capacitor
B	Through a tapped coil
C	Through a capacitive divider
D	Through link coupling

39. - E8A06

What is the approximate ratio of PEP-to-average power in a typical single-sideband phone signal?

Select	Answer
A	1 to 1
B	100 to 1
C	2.5 to 1
D	25 to 1

40. - E8B07

Orthogonal Frequency Division Multiplexing is a technique used for which type of amateur communication?

Select	Answer
A	EME
B	Extremely low-power contacts
C	OFDM signals are not allowed on amateur bands
D	High-speed digital modes

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	Modulation index and output power
C	IF bandwidth and Q
D	All these choices are correct

42. - E8D07

What is a common cause of overmodulation of AFSK signals?

Select	Answer
A	Ground loops
B	Bit errors in the modem
C	Excessive transmit audio levels
D	Excessive numbers of retries

43. - E9A12

How much gain does an antenna have compared to a 1/2-wavelength dipole when it has 6 dB gain over an isotropic antenna?

Select	Answer
A	8.15 dB
B	2.79 dB
C	3.85 dB
D	6.0 dB

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

45. - E9C03

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

Select	Answer
A	A Figure-8 broadside to the axis of the array
B	A Figure-8 end-fire along the axis of the array
C	Cardioid
D	Omni-directional

46. - E9D06

What happens to the SWR bandwidth when one or more loading coils are used to resonate an electrically short antenna?

Select	Answer
A	It is increased
B	It is unchanged if the loading coil is located at a voltage maximum point
C	It is unchanged if the loading coil is located at the feed point
D	It is decreased

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 stub matching system
B	The omega matching system
C	The delta matching system
D	The gamma matching system

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	10.4 meters
B	5.2 meters
C	8.3 meters
D	6.9 meters

49. - E9G01

Which of the following can be calculated using a Smith chart?

Select	Answer
A	Radiation resistance
B	Impedance along transmission lines
C	Antenna radiation pattern
D	Radio propagation

50. - E9H04

What is an advantage of placing a grounded electrostatic shield around a small loop direction-finding antenna?

Select	Answer
A	It adds capacitive loading, increasing the bandwidth of the antenna
B	It increases signal strength by providing a better match to the feed line
C	It eliminates unbalanced capacitive coupling to the surroundings, improving the nulls
D	It eliminates tracking errors caused by strong out-of-band signals