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

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1. - E0A10

What toxic material may be present in some electronic components such as high voltage capacitors and transformers?

Select	Answer
A	Polytetrafluoroethylene
B	Polychlorinated biphenyls
C	Polymorphic silicon
D	Polyethylene

2. - E1A10

If an amateur station is installed aboard a ship or aircraft, what condition must be met before the station is operated?

Select	Answer
A	The amateur station operator must agree not to transmit when the main radio of the ship or aircraft is in use
B	Its operation must be approved by the master of the ship or the pilot in command of the aircraft
C	The amateur station must have a power supply that is completely independent of the main ship or aircraft power supply
D	The amateur operator must have an FCC Marine or Aircraft endorsement on his or her amateur license

3. - E1B04

What must be done before placing an amateur station within an officially designated wilderness area or wildlife preserve, or an area listed in the National Register of Historic Places?

Select	Answer
A	A proposal must be submitted to the National Park Service
B	A form FSD-15 must be submitted to the Department of the Interior
C	An Environmental Assessment must be submitted to the FCC
D	A letter of intent must be filed with the Environmental Protection Agency

4. - E1C01

What is the maximum bandwidth for a data emission on 60 meters?

Select	Answer
A	170 Hz
B	60 Hz
C	2.8 kHz
D	1.5 kHz

5. - E1D09

Which UHF amateur bands have frequencies authorized for space stations?

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

6. - E1E06

Who is responsible for the proper conduct and necessary supervision during an amateur operator license examination session?

Select	Answer
A	The VEC coordinating the session
B	The VE session manager
C	Each administering VE
D	The FCC

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. - E2A01

What is the direction of an ascending pass for an amateur satellite?

Select	Answer
A	From east to west
B	From south to north
C	From west to east
D	From north to south

9. - E2B07

What is the name of the signal component that carries color information in NTSC video?

Select	Answer
A	Luminance
B	Spectral intensity
C	Chroma
D	Hue

10. - E2C06

During a VHF/UHF contest, in which band segment would you expect to find the highest level of SSB or CW activity?

Select	Answer
A	In the weak signal segment of the band, with most of the activity near the calling frequency
B	At the top of each band, usually in a segment reserved for contests
C	In the middle of the band, usually 25 kHz above the national calling frequency
D	In the middle of each band, usually on the national calling frequency

11. - E2D11

Which of the following data are used by the APRS network to communicate station location?

Select	Answer
A	Polar coordinates
B	Latitude and longitude
C	Time and frequency
D	Radio direction finding spectrum analysis

12. - E2E04

What is indicated when one of the ellipses in an FSK crossed-ellipse display suddenly disappears?

Select	Answer
A	One of the signal filters is saturated
B	The receiver has drifted 5 kHz from the desired receive frequency
C	The mark and space signal have been inverted
D	Selective fading has occurred

13. - E3A06

What might help to restore contact when DX signals become too weak to copy across an entire HF band a few hours after sunset?

Select	Answer
A	Switch to a higher frequency HF band
B	Wait 24 hours before attempting another communication on the band
C	Wait 90 minutes or so for the signal degradation to pass
D	Switch to a lower frequency HF band

14. - E3B09

At what time of year is sporadic E propagation most likely to occur?

Select	Answer
A	Around the equinoxes, especially the spring equinox
B	Around the equinoxes, especially the fall equinox
C	Around the solstices, especially the winter solstice
D	Around the solstices, especially the summer solstice

15. - E3C07

Which of the following descriptors indicates the greatest solar flare intensity?

Select	Answer
A	Class M
B	Class X
C	Class A
D	Class B

16. - E4A09

Which of the following is good practice when using an oscilloscope probe?

Select	Answer
A	All these choices are correct
B	Keep the signal ground connection of the probe as short as possible
C	Never use a DC-coupled probe to measure an AC circuit
D	Never use a high-impedance probe to measure a low-impedance circuit

17. - E4B04

Which S parameter represents input port return loss or reflection coefficient (equivalent to VSWR)?

Select	Answer
A	S12
B	S11
C	S22
D	S21

18. - E4C15

What is reciprocal mixing?

Select	Answer
A	Two out-of-band signals mixing to generate an in-band spurious signal
B	Two digital signals combining from alternate time slots
C	Local oscillator phase noise mixing with adjacent strong signals to create interference to desired signals
D	In-phase signals cancelling in a mixer resulting in loss of receiver sensitivity

19. - E4D12

What is the term for the reduction in receiver sensitivity caused by a strong signal near the received frequency?

Select	Answer
A	Quieting
B	Squelch gain rollback
C	Cross-modulation interference
D	Desensitization

20. - E4E09

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

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

21. - E5A13

What is an effect of increasing Q in a series resonant circuit?

Select	Answer
A	Phase shift can become uncontrolled
B	Internal voltages increase
C	Fewer components are needed for the same performance
D	Parasitic effects are minimized

22. - E5B09

What is the relationship between the AC current through a capacitor and the voltage across a capacitor?

Select	Answer
A	Current leads voltage by 90 degrees
B	Voltage leads current by 90 degrees
C	Voltage and current are 180 degrees out of phase
D	Voltage and current are in phase

23. - E5C12

Which point on Figure E5-1 best represents the impedance of a series circuit consisting of a 300-ohm resistor and a 19-picofarad capacitor at 21.200 MHz?

Select	Answer
A	Point 3
B	Point 8
C	Point 7
D	Point 1

24. - E5D14

What is reactive power?

Select	Answer
A	Power consumed in circuit Q
B	Wattless, nonproductive power
C	Power lost because of capacitor leakage
D	Power consumed in wire resistance in an inductor

25. - E6A04

What is the name given to an impurity atom that adds holes to a semiconductor crystal structure?

Select	Answer
A	Donor impurity
B	N-type impurity
C	Insulator impurity
D	Acceptor impurity

26. - E6B05

What characteristic of a PIN diode makes it useful as an RF switch?

Select	Answer
A	Reverse bias controls its forward voltage drop
B	Extremely high reverse breakdown voltage
C	Low junction capacitance
D	Ability to dissipate large amounts of power

27. - E6C06

Why do CMOS digital integrated circuits have high immunity to noise on the input signal or power supply?

Select	Answer
A	Bandwidth is very limited
B	The input switching threshold is about two times the power supply voltage
C	Large bypass capacitance is inherent
D	The input switching threshold is about one-half the power supply voltage

28. - E6D13

What is the primary cause of inductor self-resonance?

Select	Answer
A	The skin effect
B	Inter-turn capacitance
C	Non-linear core hysteresis
D	Inductive kickback

29. - E6E10

What advantage does surface-mount technology offer at RF compared to using through-hole components?

Select	Answer
A	Smaller circuit area
B	Shorter circuit-board traces
C	All these choices are correct
D	Components have less parasitic inductance and capacitance

30. - E6F05

Which describes an optical shaft encoder?

Select	Answer
A	A device that detects rotation of a control by interrupting a light source with a patterned wheel
B	A device that measures the strength of a beam of light using analog to digital conversion
C	A device for generating RTTY signals by means of a rotating light source
D	A digital encryption device often used to encrypt spacecraft control signals

31. - E7A06

What is a characteristic of a monostable multivibrator?

Select	Answer
A	It maintains a constant output voltage, regardless of variations in the input voltage
B	It switches momentarily to the opposite binary state and then returns to its original state after a set time
C	It produces a continuous square wave oscillating between 1 and 0
D	It stores one bit of data in either a 0 or 1 state

32. - E7B06

Which of the following amplifier types reduces even-order harmonics?

Select	Answer
A	Class AB
B	Class C
C	Push-push
D	Push-pull

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	An active LC filter
C	A Chebyshev filter
D	A Butterworth filter

34. - E7D02

What is a characteristic of a switching electronic voltage regulator?

Select	Answer
A	It is generally less efficient than a linear regulator
B	It gives a ramp voltage at its output
C	The resistance of a control element is varied in direct proportion to the line voltage or load current
D	The controlled device's duty cycle is changed to produce a constant average output voltage

35. - E7E03

What is a frequency discriminator stage in a FM receiver?

Select	Answer
A	An FM generator circuit
B	A circuit for detecting FM signals
C	An automatic band-switching circuit
D	A circuit for filtering two closely adjacent signals

36. - E7F04

What is a common method of generating an SSB signal using digital signal processing?

Select	Answer
A	A frequency synthesizer removes the unwanted sidebands
B	Signals are combined in quadrature phase relationship
C	Mixing products are converted to voltages and subtracted by adder circuits
D	Varying quartz crystal characteristics emulated in digital form

37. - E7G02

What is ringing in a filter?

Select	Answer
A	Undesired oscillations added to the desired signal
B	Partial cancellation of the signal over a range of frequencies
C	A reduction in high frequency response
D	An echo caused by a long time delay

38. - E7H12

Which of the following must be done to ensure that a crystal oscillator provides the frequency specified by the crystal manufacturer?

Select	Answer
A	Provide the crystal with a specified parallel inductance
B	Provide the crystal with a specified parallel capacitance
C	Bias the crystal at a specified current
D	Bias the crystal at a specified voltage

39. - E8A04

What is "dither" with respect to analog-to-digital converters?

Select	Answer
A	A small amount of noise added to the input signal to allow more precise representation of a signal over time
B	An error caused by irregular quantization step size
C	An abnormal condition where the converter cannot settle on a value to represent the signal
D	A method of decimation by randomly skipping samples

40. - E8B09

What is deviation ratio?

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

41. - E8C08

How does ARQ accomplish error correction?

Select	Answer
A	If errors are detected, a retransmission is requested
B	If errors are detected, redundant data is substituted
C	Special polynomial codes provide automatic correction
D	Special binary codes provide automatic correction

42. - E8D04

What is the primary effect of extremely short rise or fall time on a CW signal?

Select	Answer
A	Limits data speed
B	The generation of key clicks
C	More difficult to copy
D	The generation of RF harmonics

43. - E9A02

What is the effective radiated power relative to a dipole of a repeater station with 150 watts transmitter power output, 2 dB feed line loss, 2.2 dB duplexer loss, and 7 dBd antenna gain?

Select	Answer
A	78.7 watts
B	1977 watts
C	286 watts
D	420 watts

44. - E9B01

In the antenna radiation pattern shown in Figure E9-1, what is the beamwidth?

Select	Answer
A	25 degrees
B	75 degrees
C	50 degrees
D	30 degrees

45. - E9C02

What is the radiation pattern of two 1/4-wavelength vertical antennas spaced 1/4 wavelength apart and fed 90 degrees out of 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	Omni-directional
D	Cardioid

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

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	450 ohms
B	50 ohms
C	62 ohms
D	75 ohms

48. - E9F03

Why is the physical length of a coaxial cable transmission line shorter than its electrical length?

Select	Answer
A	The surge impedance is higher in a parallel feed line
B	Skin effect is less pronounced in the coaxial cable
C	Electrical signals move more slowly in a coaxial cable than in air
D	The characteristic impedance is higher in a parallel feed line

49. - E9G04

What are the two families of circles and arcs that make up a Smith chart?

Select	Answer
A	Resistance and voltage
B	Voltage and impedance
C	Reactance and voltage
D	Resistance and reactance

50. - E9H02

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

Select	Answer
A	All these choices are correct
B	They must be erected at least 1/2 wavelength above the ground to attain good directivity
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 E5-1

Figure E9-1