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. - E1A01

Which of the following carrier frequencies is illegal for LSB AFSK emissions on the 17 meter band RTTY and data segment of 18.068 to 18.110 MHz?

Select	Answer
A	18.068 MHz
B	18.110 MHz
C	18.100 MHz
D	18.107 MHz

3. - E1B12

What must the control operator of a repeater operating in the 70 cm band do if a radiolocation system experiences interference from that repeater?

Select	Answer
A	All these choices are correct
B	File an FAA NOTAM (Notice to Airmen) with the repeater system's ERP, call sign, and six-character grid locator
C	Reduce the repeater antenna HAAT (Height Above Average Terrain)
D	Cease operation or make changes to the repeater to mitigate the interference

4. - E1C14

How long must an operator wait after filing a notification with the Utilities Technology Council (UTC) before operating on the 2200 meter or 630 meter band?

Select	Answer
A	Operations may commence immediately, and may continue unless interference is reported by the UTC
B	Operators may not operate until a test signal has been transmitted in coordination with the local power company
C	Operators must not operate until approval is received
D	Operators may operate after 30 days, providing they have not been told that their station is within 1 km of PLC systems using those frequencies

5. - E1D04

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

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

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 FCC
C	The VEs
D	The VECs

7. - E1F04

Which of the following geographic descriptions approximately describes "Line A"?

Select	Answer
A	A line roughly parallel to and north of the border between the U.S. and Mexico
B	A line roughly parallel to and east of the U.S. Pacific coastline
C	A line roughly parallel to and south of the border between the U.S. and Canada
D	A line roughly parallel to and west of the U.S. Atlantic coastline

8. - E2A13

Which of the following techniques is normally used by low Earth orbiting digital satellites to relay messages around the world?

Select	Answer
A	Multi-satellite relaying
B	Store-and-forward
C	Digipeating
D	Node hopping

9. - E2B05

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

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

10. - E2C05

What is the function of a DX QSL Manager?

Select	Answer
A	To allocate frequencies for DXpeditions
B	To relay calls to and from a DX station
C	To handle the receiving and sending of confirmation cards for a DX station
D	To run a net to allow many stations to contact a rare DX station

11. - E2D03

Which of the following digital modes is especially useful for EME communications?

Select	Answer
A	Olivia
B	PACTOR III
C	MSK144
D	JT65

12. - E2E11

What is the difference between direct FSK and audio FSK?

Select	Answer
A	Only direct FSK can be decoded by computer
B	Direct FSK occupies less bandwidth
C	Direct FSK can transmit faster baud rates
D	Direct FSK applies the data signal to the transmitter VFO, while AFSK transmits tones via phone

13. - E3A11

What is a typical range for tropospheric propagation of microwave signals?

Select	Answer
A	100 miles to 300 miles
B	1200 miles
C	10 miles to 50 miles
D	2500 miles

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	Refracted rays and reflected waves
C	Independent waves created in the ionosphere that are elliptically polarized
D	Long-path and short-path waves

15. - E3C04

What does the value of Bz (B sub Z) represent?

Select	Answer
A	Critical frequency for vertical transmissions
B	Geomagnetic field stability
C	Direction and strength of the interplanetary magnetic field
D	Duration of long-delayed echoes

16. - E4A10

Which of the following displays multiple digital signal states simultaneously?

Select	Answer
A	Network analyzer
B	Logic analyzer
C	Modulation monitor
D	Bit error rate tester

17. - E4B09

What is indicated if the current reading on an RF ammeter placed in series with the antenna feed line of a transmitter increases as the transmitter is tuned to resonance?

Select	Answer
A	There is an impedance mismatch between the antenna and feed line
B	There is possibly a short to ground in the feed line
C	The transmitter is not properly neutralized
D	There is more power going into the antenna

18. - E4C06

A CW receiver with the AGC off has an equivalent input noise power density of -174 dBm/Hz. What would be the level of an unmodulated carrier input to this receiver that would yield an audio output SNR of 0 dB in a 400 Hz noise bandwidth?

Select	Answer
A	-174 dBm
B	-148 dBm
C	-155 dBm
D	-164 dBm

19. - E4D02

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

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

20. - E4E10

What might be the cause of a loud roaring or buzzing AC line interference that comes and goes at intervals?

Select	Answer
A	All these choices are correct
B	A malfunctioning illuminated advertising display
C	Arcing contacts in a thermostatically controlled device
D	A defective doorbell or doorbell transformer inside a nearby residence

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 kHz
B	23.5 MHz
C	7.12 MHz
D	7.12 kHz

22. - E5B03

How is impedance in polar form converted to an equivalent admittance?

Select	Answer
A	Take the square root of the magnitude and add 180 degrees to the angle
B	Take the reciprocal of the angle and change the sign of the magnitude
C	Take the reciprocal of the magnitude and change the sign of the angle
D	Square the magnitude and subtract 90 degrees from the angle

23. - E5C02

How are impedances described in polar coordinates?

Select	Answer
A	By Y and G values
B	By X and R values
C	By phase angle and magnitude
D	By real and imaginary parts

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	0.577
B	0.866
C	1.73
D	0.5

25. - E6A01

In what application is gallium arsenide used as a semiconductor material?

Select	Answer
A	In high-power audio circuits
B	In microwave circuits
C	In very low-frequency RF circuits
D	In high-current rectifier circuits

26. - E6B07

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

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

27. - E6C08

In Figure E6-3, what is the schematic symbol for a NAND gate?

Select	Answer
A	1
B	2
C	3
D	4

28. - E6D06

What core material property determines the inductance of an inductor?

Select	Answer
A	Permeability
B	Resistance
C	Reactivity
D	Thermal impedance

29. - E6E09

Which of the following component package types would be most suitable for use at frequencies above the HF range?

Select	Answer
A	Axial lead
B	Surface mount
C	Radial lead
D	TO-220

30. - E6F10

What is the most common type of photovoltaic cell used for electrical power generation?

Select	Answer
A	Cadmium Sulfide
B	Copper oxide
C	Selenium
D	Silicon

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

32. - E7B13

Which of the following describes an emitter follower (or common collector) amplifier?

Select	Answer
A	A two-transistor amplifier with the emitters sharing a common bias resistor
B	A differential amplifier with both inputs fed to the emitter of the input transistor
C	An OR circuit with only one emitter used for output
D	An amplifier with a low impedance output that follows the base input voltage

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

34. - E7D13

What is the equation for calculating power dissipated by a series linear voltage regulator?

Select	Answer
A	Input voltage divided by output current
B	Voltage difference from input to output multiplied by output current
C	Input voltage multiplied by input current
D	Output voltage multiplied by output current

35. - E7E01

Which of the following can be used to generate FM phone emissions?

Select	Answer
A	A reactance modulator on the oscillator
B	A balanced modulator on the oscillator
C	A balanced modulator on the audio amplifier
D	A reactance modulator on the final amplifier

36. - E7F14

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

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

37. - E7G08

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

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

38. - E7H14

What is a phase-locked loop circuit?

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

39. - E8A09

How many different input levels can be encoded by an analog-to-digital converter with 8-bit resolution?

Select	Answer
A	8 multiplied by the gain of the input amplifier
B	256
C	256 divided by the gain of the input amplifier
D	8

40. - E8B05

What is the deviation ratio of an FM-phone signal having a maximum frequency swing of plus-or-minus 5 kHz when the maximum modulation frequency is 3 kHz?

Select	Answer
A	60
B	0.167
C	1.67
D	0.6

41. - E8C07

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

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

42. - E8D08

What parameter evaluates distortion of an AFSK signal caused by excessive input audio levels?

Select	Answer
A	Intermodulation Distortion (IMD)
B	Signal-to-noise ratio
C	Repeat Request Rate (RRR)
D	Baud rate

43. - E9A03

What is the radiation resistance of an antenna?

Select	Answer
A	The combined losses of the antenna elements and feed line
B	The specific impedance of the antenna
C	The resistance in the atmosphere that an antenna must overcome to be able to radiate a signal
D	The value of a resistance that would dissipate the same amount of power as that radiated from an antenna

44. - E9B11

What is a disadvantage of decreasing the number of wire segments in an antenna model below 10 segments per half-wavelength?

Select	Answer
A	The antenna will become mechanically unstable
B	The computed feed point impedance may be incorrect
C	Ground conductivity will not be accurately modeled
D	The resulting design will favor radiation of harmonic energy

45. - E9C06

What is the effect of adding a terminating resistor to a rhombic antenna?

Select	Answer
A	It decreases the ground loss
B	It reflects the standing waves on the antenna elements back to the transmitter
C	It changes the radiation pattern from bidirectional to unidirectional
D	It changes the radiation pattern from horizontal to vertical polarization

46. - E9D04

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

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

47. - E9E04

What is the purpose of the series capacitor in a gamma-type antenna matching network?

Select	Answer
A	To cancel the inductive reactance of the matching network
B	To transform the antenna impedance to a higher value
C	To provide a rejection notch that prevents the radiation of harmonics
D	To provide DC isolation between the feed line and the antenna

48. - E9F08

Which of the following is a significant difference between foam dielectric coaxial cable and solid dielectric cable, assuming all other parameters are the same?

Select	Answer
A	Foam dielectric has higher velocity factor
B	Foam dielectric has lower safe operating voltage limits
C	Foam dielectric has lower loss per unit of length
D	All these choices are correct

49. - E9G04

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

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

50. - E9H06

What is the triangulation method of direction finding?

Select	Answer
A	Antenna headings from several different receiving locations are used to locate the signal source
B	A fixed receiving station plots three headings to the signal source
C	A fixed receiving station uses three different antennas to plot the location of the signal source
D	The geometric angles of sky waves from the source are used to determine its position

Figure E6-3