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

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1. - E0A11

Which of the following injuries can result from using high-power UHF or microwave transmitters?

Select	Answer
A	Localized heating of the body from RF exposure in excess of the MPE limits
B	Hearing loss caused by high voltage corona discharge
C	Ingestion of ozone gas from the cooling system
D	Blood clotting from the intense magnetic field

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

3. - E1B09

Which amateur stations may be operated under RACES rules?

Select	Answer
A	Any FCC-licensed amateur station participating in the Military Auxiliary Radio System (MARS)
B	Any FCC-licensed amateur station certified by the responsible civil defense organization for the area served
C	Any FCC-licensed amateur station except a Technician Class
D	Only those club stations licensed to Amateur Extra Class operators

4. - E1C03

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

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

5. - E1D07

Which HF amateur bands have frequencies authorized for space stations?

Select	Answer
A	All HF bands
B	Only the 40, 20, 17, 15, 12, and 10 meter bands
C	Only the 40, 30, 20, 15, 12, and 10 meter bands
D	Only the 40, 20, 17, 15, and 10 meter bands

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

7. - E1F08

Which of the following types of amateur station communications are prohibited?

Select	Answer
A	Communications in a language other than English
B	Communications that have religious content
C	Communications that have political content, except as allowed by the Fairness Doctrine
D	Communications transmitted for hire or material compensation, except as otherwise provided in the rules

8. - E2A04

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

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

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

10. - E2C10

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

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

11. - E2D10

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

Select	Answer
A	APRS stations with General Personnel Scanners can automatically relay the participant numbers and time as they pass the check points
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	An APRS station with a Global Positioning System unit can automatically transmit information to show a mobile station's position during the event

12. - E2E10

Which of these digital modes has the narrowest bandwidth?

Select	Answer
A	MFSK16
B	PSK31
C	170 Hz shift, 45-baud RTTY
D	300-baud packet

13. - E3A05

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

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

14. - E3B10

Why is chordal hop propagation desirable?

Select	Answer
A	Atmospheric noise is lower in the direction of chordal hop propagation
B	The MUF for chordal hop propagation is much lower than for normal skip propagation
C	Signals travel faster along ionospheric chords
D	The signal experiences less loss compared to multi-hop using Earth as a reflector

15. - E3C09

How does the intensity of an X3 flare compare to that of an X2 flare?

Select	Answer
A	10 percent greater
B	50 percent greater
C	Twice as great
D	Four times as great

16. - E4A05

What is the purpose of the prescaler function on a frequency counter?

Select	Answer
A	It divides a higher frequency signal so a low-frequency counter can display the input frequency
B	It amplifies low-level signals for more accurate counting
C	It prevents oscillation in a low-frequency counter circuit
D	It multiplies a higher frequency signal so a low-frequency counter can display the operating frequency

17. - E4B11

Which of the following can be measured with a vector network analyzer?

Select	Answer
A	Reflection coefficient
B	All these choices are correct
C	Output impedance
D	Input impedance

18. - E4C07

What does the MDS of a receiver represent?

Select	Answer
A	The multiplex distortion stability
B	The minimum discernible signal
C	The meter display sensitivity
D	The maximum detectable spectrum

19. - E4D06

What is the term for spurious signals generated by the combination of two or more signals in a non-linear device or circuit?

Select	Answer
A	Amplifier desensitization
B	Adjacent channel interference
C	Intermodulation
D	Neutralization

20. - E4E09

What undesirable effect can occur when using an IF noise blanker?

Select	Answer
A	The audio frequency bandwidth of the received signal might be compressed
B	Received audio in the speech range might have an echo effect
C	FM signals can no longer be demodulated
D	Nearby signals may appear to be excessively wide even if they meet emission standards

21. - E5A16

What is the resonant frequency of an RLC circuit if R is 33 ohms, L is 50 microhenries and C is 10 picofarads?

Select	Answer
A	23.5 MHz
B	23.5 kHz
C	7.12 kHz
D	7.12 MHz

22. - E5B04

What is the time constant of a circuit having two 220-microfarad capacitors and two 1-megohm resistors, all in parallel?

Select	Answer
A	110 seconds
B	440 seconds
C	220 seconds
D	55 seconds

23. - E5C03

Which of the following represents an inductive reactance in polar coordinates?

Select	Answer
A	A negative phase angle
B	A negative magnitude
C	A positive phase angle
D	A positive magnitude

24. - E5D03

What is microstrip?

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

25. - E6A03

Why does a PN-junction diode not conduct current when reverse biased?

Select	Answer
A	Only N-type semiconductor material can conduct current
B	Holes in P-type material and electrons in the N-type material are separated by the applied voltage, widening the depletion region
C	Only P-type semiconductor material can conduct current
D	Excess holes in P-type material combine with the electrons in N-type material, converting the entire diode into an insulator

26. - E6B09

What is a common use for point-contact diodes?

Select	Answer
A	As a constant current source
B	As a constant voltage source
C	As a high-voltage rectifier
D	As an RF detector

27. - E6C07

What best describes a pull-up or pull-down resistor?

Select	Answer
A	A resistor connected to an op-amp output that prevents signals from exceeding the power supply voltage
B	A resistor that ensures that an oscillator frequency does not drift
C	A resistor in a keying circuit used to reduce key clicks
D	A resistor connected to the positive or negative supply line used to establish a voltage when an input or output is an open circuit

28. - E6D11

Which type of core material decreases inductance when inserted into a coil?

Select	Answer
A	Brass
B	Powdered iron
C	Ceramic
D	Ferrite

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	Two chips in each package (Dual In Package)
D	Low leakage doubly insulated package

30. - E6F11

What is the approximate open-circuit voltage produced by a fully illuminated silicon photovoltaic cell?

Select	Answer
A	12 V
B	0.1 V
C	1.5 V
D	0.5 V

31. - E7A09

What logical operation is performed by an exclusive NOR gate?

Select	Answer
A	It produces logic 1 at its output only if all inputs are logic 1
B	It produces logic 0 at its output only if all inputs are logic 0
C	It produces logic 1 at its output if only one input is logic 1
D	It produces logic 0 at its output if only one input is logic 1

32. - E7B15

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

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

33. - E7C01

How are the capacitors and inductors of a low-pass filter Pi-network arranged between the network's input and output?

Select	Answer
A	A capacitor is connected between the input and ground, another capacitor is connected between the output and ground, and an inductor is connected between input and output
B	Two inductors are in series between the input and output, and a capacitor is connected between the two inductors and ground
C	An inductor is connected between the input and ground, another inductor is connected between the output and ground, and a capacitor is connected between the input and output
D	Two capacitors are in series between the input and output, and an inductor is connected between the two capacitors and ground

34. - E7D07

What is the purpose of C2 in the circuit shown in Figure E7-2?

Select	Answer
A	It is a brute force filter for the output
B	To self-resonate at the hum frequency
C	To provide fixed DC bias for Q1
D	It bypasses rectifier output ripple around D1

35. - E7E10

How does a diode envelope detector function?

Select	Answer
A	By mixing signals with noise in the transition region of the diode
B	By breakdown of the Zener voltage
C	By sensing the change of reactance in the diode with respect to frequency
D	By rectification and filtering of RF signals

36. - E7F01

What is meant by direct digital conversion as applied to software defined radios?

Select	Answer
A	Software is converted from source code to object code during operation of the receiver
B	A switching mixer is used to generate I and Q signals directly from the RF input
C	Incoming RF is converted to a control voltage for a voltage controlled oscillator
D	Incoming RF is digitized by an analog-to-digital converter without being mixed with a local oscillator signal

37. - E7G08

How does the gain of an ideal operational amplifier vary with frequency?

Select	Answer
A	It decreases linearly with increasing frequency
B	It increases linearly with increasing frequency
C	It decreases logarithmically with increasing frequency
D	It does not vary with frequency

38. - E7H14

What is a phase-locked loop circuit?

Select	Answer
A	An electronic circuit also known as a monostable multivibrator
B	An electronic servo loop consisting of a ratio detector, reactance modulator, and voltage-controlled oscillator
C	An electronic servo loop consisting of a phase detector, a low-pass filter, a voltage-controlled oscillator, and a stable reference oscillator
D	An electronic circuit consisting of a precision push-pull amplifier with a differential input

39. - E8A07

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

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

40. - E8B09

What is deviation ratio?

Select	Answer
A	The ratio of the carrier center frequency to the audio modulating frequency
B	The ratio of the highest audio modulating frequency to the average audio modulating frequency
C	The ratio of the maximum carrier frequency deviation to the highest audio modulating frequency
D	The ratio of the audio modulating frequency to the center carrier frequency

41. - E8C06

What is the bandwidth of a 170-hertz shift, 300-baud ASCII transmission?

Select	Answer
A	1.0 kHz
B	0.1 Hz
C	0.3 kHz
D	0.5 kHz

42. - E8D03

How does the spread spectrum technique of frequency hopping work?

Select	Answer
A	A binary bit stream is used to shift the phase of an RF carrier very rapidly in a pseudorandom sequence
B	The frequency of the transmitted signal is changed very rapidly according to a pseudorandom sequence also used by the receiving station
C	If interference is detected by the receiver it will signal the transmitter to change frequencies
D	If interference is detected by the receiver it will signal the transmitter to wait until the frequency is clear

43. - E9A10

Which of the following improves the efficiency of a ground-mounted quarter-wave vertical antenna?

Select	Answer
A	All these choices are correct
B	Shortening the radiating element
C	Isolating the coax shield from ground
D	Installing a radial system

44. - E9B04

What is the front-to-back ratio of the radiation pattern shown in Figure E92?

Select	Answer
A	28 dB
B	3 dB
C	15 dB
D	38 dB

45. - E9C14

How does the performance of a horizontally polarized antenna mounted on the side of a hill compare with the same antenna mounted on flat ground?

Select	Answer
A	The main lobe takeoff angle increases in the downhill direction
B	The main lobe takeoff angle decreases in the downhill direction
C	The horizontal beamwidth decreases in the downhill direction
D	The horizontal beamwidth increases in the uphill direction

46. - E9D04

Why should an HF mobile antenna loading coil have a high ratio of reactance to resistance?

Select	Answer
A	To lower the radiation angle
B	To minimize losses
C	To minimize the Q
D	To swamp out harmonics

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

48. - E9F04

What impedance does a 1/2-wavelength transmission line present to a generator when the line is shorted at the far end?

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

49. - E9G05

Which of the following is a common use for a Smith chart?

Select	Answer
A	Determine the gain of an antenna given the physical and electrical parameters
B	Determine the loss/100 feet of a transmission line, given the velocity factor and conductor materials
C	Determine the length and position of an impedance matching stub
D	Determine the impedance of a transmission line, given the physical dimensions

50. - E9H07

Why is RF attenuation used when direction-finding?

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

Figure E7-2