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. - E1A08

If a station in a message forwarding system inadvertently forwards a message that is in violation of FCC rules, who is primarily accountable for the rules violation?

Select	Answer
A	The control operator of the packet bulletin board station
B	The control operators of all the stations in the system not authenticating the source from which they accept communications
C	The control operators of all the stations in the system
D	The control operator of the originating station

3. - E1B08

What limitations may the FCC place on an amateur station if its signal causes interference to domestic broadcast reception, assuming that the receivers involved are of good engineering design?

Select	Answer
A	The amateur station must avoid transmitting during certain hours on frequencies that cause the interference
B	The amateur station must cease operation
C	The amateur station must cease operation on all frequencies above 30 MHz
D	The amateur station must cease operation on all frequencies below 30 MHz

4. - E1C03

How do the control operator responsibilities of a station under automatic control differ from one under local control?

Select	Answer
A	Under automatic control the control operator is not required to be present at the control point
B	Under local control a control operator is not required to be present at a control point
C	Under automatic control there is no control operator
D	Under local control there is no control operator

5. - E1D08

Which VHF amateur bands have frequencies authorized for space stations?

Select	Answer
A	2 meters
B	6 meters and 2 meters
C	6 meters, 2 meters, and 1.25 meters
D	2 meters and 1.25 meters

6. - E1E04

Which of the following best describes the Volunteer Examiner accreditation process?

Select	Answer
A	The prospective VE obtains accreditation from the FCC
B	The amateur operator applying must pass a VE examination administered by the FCC Enforcement Bureau
C	The procedure by which a VEC confirms that the VE applicant meets FCC requirements to serve as an examiner
D	Each General, Advanced and Amateur Extra Class operator is automatically accredited as a VE when the license is granted

7. - E1F03

Under what circumstances may a dealer sell an external RF power amplifier capable of operation below 144 MHz if it has not been granted FCC certification?

Select	Answer
A	The equipment dealer assembled it from a kit
B	It was purchased in used condition from an amateur operator and is sold to another amateur operator for use at that operator's station
C	It was imported from a manufacturer in a country that does not require certification of RF power amplifiers
D	It was imported from a manufacturer in another country and was certificated by that country's government

8. - E2A07

Which of the following types of signals can be relayed through a linear transponder?

Select	Answer
A	FM and CW
B	PSK and packet
C	All these choices are correct
D	SSB and SSTV

9. - E2B10

What aspect of an analog slow-scan television signal encodes the brightness of the picture?

Select	Answer
A	Tone amplitude
B	Sync amplitude
C	Tone frequency
D	Sync frequency

10. - E2C04

Which of the following frequencies are sometimes used for amateur radio mesh networks?

Select	Answer
A	Frequencies shared with various unlicensed wireless data services
B	HF frequencies where digital communications are permitted
C	Cable TV channels 41 through 43
D	The 60 meter band channel centered on 5373 kHz

11. - E2D05

What is one advantage of the JT65 mode?

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

12. - E2E06

What is the most common data rate used for HF packet?

Select	Answer
A	1200 baud
B	300 baud
C	110 baud
D	48 baud

13. - E3A04

What do Hepburn maps predict?

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

14. - E3B05

Which amateur bands typically support long-path propagation?

Select	Answer
A	Only 30 meters to 10 meters
B	160 meters to 10 meters
C	Only 160 meters to 40 meters
D	6 meters to 2 meters

15. - E3C05

What orientation of Bz (B sub z) increases the likelihood that incoming particles from the sun will cause disturbed conditions?

Select	Answer
A	Eastward
B	Westward
C	Northward
D	Southward

16. - E4A11

How should an antenna analyzer be connected when measuring antenna resonance and feed point impedance?

Select	Answer
A	Loosely couple the analyzer near the antenna base
B	Connect the antenna feed line directly to the analyzer's connector
C	Loosely couple the antenna and a dummy load to the analyzer
D	Connect the analyzer via a high-impedance transformer to the antenna

17. - E4B03

Which S parameter is equivalent to forward gain?

Select	Answer
A	S11
B	S12
C	S22
D	S21

18. - E4C11

Why can an attenuator be used to reduce receiver overload on the lower frequency HF bands with little or no impact on signal-to-noise ratio?

Select	Answer
A	Atmospheric noise is generally greater than internally generated noise even after attenuation
B	Signals are attenuated separately from the noise
C	The attenuator has a noise filter to suppress interference
D	The attenuator has a low-pass filter to increase the strength of lower frequency signals

19. - E4D02

Which of the following describes problems caused by poor dynamic range in a receiver?

Select	Answer
A	Cross-modulation of the desired signal and insufficient audio power to operate the speaker
B	Oscillator instability requiring frequent retuning and loss of ability to recover the opposite sideband
C	Oscillator instability and severe audio distortion of all but the strongest received signals
D	Spurious signals caused by cross-modulation and desensitization from strong adjacent signals

20. - E4E07

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

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

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	High compared to the circuit resistance
C	Approximately equal to circuit resistance
D	Approximately equal to inductive reactance

22. - E5B06

What is susceptance?

Select	Answer
A	The magnetic impedance of a circuit
B	The ratio of magnetic field to electric field
C	A measure of the efficiency of a transformer
D	The imaginary part of admittance

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 2
C	Point 4
D	Point 6

24. - E5D05

What is the power factor of an RL circuit having a 30-degree phase angle between the voltage and the current?

Select	Answer
A	0.5
B	1.73
C	0.866
D	0.577

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

26. - E6B07

What is the failure mechanism when a junction diode fails due to excessive current?

Select	Answer
A	Charge carrier depletion
B	Excessive junction temperature
C	Excessive inverse voltage
D	Insufficient forward voltage

27. - E6C09

What is a Programmable Logic Device (PLD)?

Select	Answer
A	A logic circuit that can be modified during use
B	A programmable collection of logic gates and circuits in a single integrated circuit
C	Programmable equipment used for testing digital logic integrated circuits
D	A type of transistor whose gain can be changed by digital logic circuits

28. - E6D04

Which materials are commonly used as a core in an inductor?

Select	Answer
A	Cobalt and aluminum
B	Teflon and Delrin
C	Ferrite and brass
D	Polystyrene and polyethylene

29. - E6E04

Which is the most common input and output impedance of circuits that use MMICs?

Select	Answer
A	450 ohms
B	10 ohms
C	50 ohms
D	300 ohms

30. - E6F03

What is the most common configuration of an optoisolator or optocoupler?

Select	Answer
A	A lens and a photomultiplier
B	A frequency modulated helium-neon laser
C	An amplitude modulated helium-neon laser
D	An LED and a phototransistor

31. - E7A08

What logical operation does an OR gate perform?

Select	Answer
A	It only produces logic 0 at its output when all inputs are logic 1
B	It produces logic 0 at its output if all inputs are logic 1
C	It produces logic 1 at its output if all inputs are logic 0
D	It produces logic 1 at its output if any or all inputs are logic 1

32. - E7B12

What type of amplifier circuit is shown in Figure E7-1?

Select	Answer
A	Common base
B	Emitter follower
C	Common emitter
D	Common collector

33. - E7C04

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

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

34. - E7D01

How does a linear electronic voltage regulator work?

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

35. - E7E08

What are the principal frequencies that appear at the output of a mixer circuit?

Select	Answer
A	Two and four times the original frequency
B	The two input frequencies along with their sum and difference frequencies
C	1.414 and 0.707 times the input frequency
D	The square root of the product of input frequencies

36. - E7F07

What function is performed by a Fast Fourier Transform?

Select	Answer
A	Converting digital signals from the time domain to the frequency domain
B	Converting 8-bit data to 16-bit data
C	Converting digital signals to analog form
D	Converting analog signals to digital form

37. - E7G09

What will be the output voltage of the circuit shown in Figure E7-3 if R1 is 1000 ohms, RF is 10,000 ohms, and 0.23 volts DC is applied to the input?

Select	Answer
A	-0.23 volts
B	-2.3 volts
C	2.3 volts
D	0.23 volts

38. - E7H02

What is a microphonic?

Select	Answer
A	Distortion caused by RF pickup on the microphone cable
B	An IC used for amplifying microphone signals
C	Changes in oscillator frequency due to mechanical vibration
D	Excess loading of the microphone by an oscillator

39. - E8A07

What determines the PEP-to-average power ratio of a single-sideband phone signal?

Select	Answer
A	Speech characteristics
B	The degree of carrier suppression
C	The frequency of the modulating signal
D	Amplifier gain

40. - E8B11

What is digital time division multiplexing?

Select	Answer
A	Two or more data streams are assigned to discrete sub-carriers on an FM transmitter
B	Two or more data streams share the same channel by transmitting time of transmission as the sub-carrier
C	Two or more signals are quadrature modulated to increase bandwidth efficiency
D	Two or more signals are arranged to share discrete time slots of a data transmission

41. - E8C07

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

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

42. - E8D06

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

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

43. - E9A11

Which of the following factors determines ground losses for a ground-mounted vertical antenna operating in the 3 MHz to 30 MHz range?

Select	Answer
A	Soil conductivity
B	Distance from the transmitter
C	The standing wave ratio
D	Take-off angle

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

45. - E9C09

Which of the following describes a G5RV antenna?

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

46. - E9D10

What happens to feed-point impedance at the base of a fixed length HF mobile antenna when operated below its resonant frequency?

Select	Answer
A	The radiation resistance increases and the capacitive reactance increases
B	The radiation resistance decreases and the capacitive reactance increases
C	The radiation resistance increases and the capacitive reactance decreases
D	The radiation resistance decreases and the capacitive reactance decreases

47. - E9E06

Which of these feed line impedances would be suitable for constructing a quarter-wave Q-section for matching a 100-ohm loop to 50-ohm feed line?

Select	Answer
A	75 ohms
B	50 ohms
C	450 ohms
D	62 ohms

48. - E9F12

What impedance does a 1/4-wavelength transmission line present to a generator when the line is open at the far end?

Select	Answer
A	Very high impedance
B	Very low impedance
C	The same as the input impedance to the generator
D	The same as the characteristic impedance of the line

49. - E9G01

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

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

50. - E9H08

What is the function of a sense antenna?

Select	Answer
A	It allows DF antennas to receive signals at different vertical angles
B	It modifies the pattern of a DF antenna array to provide a null in one direction
C	It provides diversity reception that cancels multipath signals
D	It increases the sensitivity of a DF antenna array

Figure E5-1

Figure E7-1

Figure E7-3