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	Polymorphic silicon
C	Polyethylene
D	Polychlorinated biphenyls

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	18.107 MHz
B	18.100 MHz
C	18.110 MHz
D	18.068 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. - E1C01

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

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

5. - E1D10

Which amateur stations are eligible to be telecommand stations of space stations (subject to the privileges of the class of operator license held by the control operator of the station)?

Select	Answer
A	Any amateur station designated by NASA
B	All these choices are correct
C	Any amateur station so designated by the ITU
D	Any amateur station so designated by the space station licensee

6. - E1E10

What must the administering VEs do after the administration of a successful examination for an amateur operator license?

Select	Answer
A	They must submit the application document to the coordinating VEC according to the coordinating VEC instructions
B	They must collect and send the documents to the NCVEC for grading
C	They must collect and send the documents to the FCC according to instructions
D	They must collect and submit the documents to the coordinating VEC for grading

7. - E1F02

What privileges are authorized in the U.S. to persons holding an amateur service license granted by the government of Canada?

Select	Answer
A	Full privileges, up to and including those of the Amateur Extra Class license, on the 80, 40, 20, 15, and 10 meter bands
B	The operating terms and conditions of the Canadian amateur service license, not to exceed U.S. Amateur Extra Class license privileges
C	None, they must obtain a U.S. license
D	All privileges of the Amateur Extra Class license

8. - E2A08

Why should effective radiated power to a satellite that uses a linear transponder be limited?

Select	Answer
A	To prevent the satellite from emitting out-of-band signals
B	To prevent creating errors in the satellite telemetry
C	To avoid reducing the downlink power to all other users
D	To avoid interfering with terrestrial QSOs

9. - E2B04

How is color information sent in analog SSTV?

Select	Answer
A	Color information is sent on a 2.8 kHz subcarrier
B	Color is amplitude modulated on the frequency modulated intensity signal
C	Color is sent in a color burst at the end of each line
D	Color lines are sent sequentially

10. - E2C01

What indicator is required to be used by U.S.-licensed operators when operating a station via remote control and the remote transmitter is located in the U.S.?

Select	Answer
A	/ followed by the ARRL Section of the remote station
B	/R# where # is the district of the remote station
C	No additional indicator is required
D	/ followed by the USPS two-letter abbreviation for the state in which the remote station is located

11. - E2D04

What technology is used to track, in real time, balloons carrying amateur radio transmitters?

Select	Answer
A	APRS
B	Ultrasonics
C	Bandwidth compressed LORAN
D	Doppler shift of beacon signals

12. - E2E09

Which of the following HF digital modes uses variable-length coding for bandwidth efficiency?

Select	Answer
A	RTTY
B	PSK31
C	MT63
D	PACTOR

13. - E3A08

When a meteor strikes the Earth's atmosphere, a cylindrical region of free electrons is formed at what layer of the ionosphere?

Select	Answer
A	The D layer
B	The F2 layer
C	The F1 layer
D	The E layer

14. - E3B02

What is the approximate maximum range for signals using transequatorial propagation?

Select	Answer
A	2500 miles
B	5000 miles
C	7500 miles
D	1000 miles

15. - E3C02

What is indicated by a rising A or K index?

Select	Answer
A	Increasing disruption of the geomagnetic field
B	Higher levels of solar UV radiation
C	Decreasing disruption of the geomagnetic field
D	An increase in the critical frequency

16. - E4A01

Which of the following limits the highest frequency signal that can be accurately displayed on a digital oscilloscope?

Select	Answer
A	Q of the circuit
B	Amount of memory
C	Sampling rate of the analog-to-digital converter
D	All these choices are correct

17. - E4B04

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

Select	Answer
A	S22
B	S21
C	S11
D	S12

18. - E4C15

What is reciprocal mixing?

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

19. - E4D08

What causes intermodulation in an electronic circuit?

Select	Answer
A	Nonlinear circuits or devices
B	Positive feedback
C	Too little gain
D	Lack of neutralization

20. - E4E05

How can radio frequency interference from an AC motor be suppressed?

Select	Answer
A	By installing a bypass capacitor in series with the motor leads
B	By installing a brute-force AC-line filter in series with the motor leads
C	By using a ground-fault current interrupter in the circuit used to power the motor
D	By installing a high-pass filter in series with the motor's power leads

21. - E5A06

What is the magnitude of the circulating current within the components of a parallel LC circuit at resonance?

Select	Answer
A	It equals 2 multiplied by pi, multiplied by frequency, multiplied by inductance
B	It equals 1 divided by the quantity 2 times pi, multiplied by the square root of inductance L multiplied by capacitance C
C	It is at a maximum
D	It is at a minimum

22. - E5B05

What happens to the magnitude of a pure reactance when it is converted to a susceptance?

Select	Answer
A	It is shifted by 90 degrees
B	It becomes the reciprocal
C	It is unchanged
D	The sign is reversed

23. - E5C06

What does the impedance 50-j25 represent?

Select	Answer
A	25 ohms resistance in series with 50 ohms inductive reactance
B	50 ohms resistance in series with 25 ohms capacitive reactance
C	50 ohms resistance in series with 25 ohms inductive reactance
D	25 ohms resistance in series with 50 ohms capacitive reactance

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	50 watts
B	2000 watts
C	80 watts
D	400 watts

25. - E6A11

In Figure E6-1, what is the schematic symbol for a P-channel junction FET?

Select	Answer
A	3
B	1
C	2
D	6

26. - E6B09

What is a common use for point-contact diodes?

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

27. - E6C05

What is an advantage of CMOS logic devices over TTL devices?

Select	Answer
A	Lower distortion
B	Immune to damage from static discharge
C	Lower power consumption
D	Differential output capability

28. - E6D01

Why should core saturation of an impedance matching transformer be avoided?

Select	Answer
A	Magnetic flux would increase with frequency
B	Temporary changes of the core permeability could result
C	RF susceptance would increase
D	Harmonics and distortion could result

29. - E6E09

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

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

30. - E6F06

Which of these materials is most commonly used to create photoconductive devices?

Select	Answer
A	A liquid semiconductor
B	An ordinary metal
C	A heavy metal
D	A crystalline semiconductor

31. - E7A05

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

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

32. - E7B13

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

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

33. - E7C06

What are the distinguishing features of an elliptical filter?

Select	Answer
A	Extremely flat response over its pass band with gradually rounded stop band corners
B	Gradual passband rolloff with extreme stop band ripple
C	Extremely sharp cutoff with one or more notches in the stop band
D	Gradual passband rolloff with minimal stop band ripple

34. - E7D10

What is the primary reason that a high-frequency switching type high-voltage power supply can be both less expensive and lighter in weight than a conventional power supply?

Select	Answer
A	It uses a diode bridge rectifier for increased output
B	It uses a large power factor compensation capacitor to recover power from the unused portion of the AC cycle
C	The inverter design does not require any output filtering
D	The high frequency inverter design uses much smaller transformers and filter components for an equivalent power output

35. - E7E07

What is meant by the term "baseband" in radio communications?

Select	Answer
A	The lowest frequency band that the transmitter or receiver covers
B	The basic oscillator frequency in an FM transmitter that is multiplied to increase the deviation and carrier frequency
C	The frequency range occupied by a message signal prior to modulation
D	The unmodulated bandwidth of the transmitted signal

36. - E7F12

Which of the following is an advantage of a Finite Impulse Response (FIR) filter vs an Infinite Impulse Response (IIR) digital filter?

Select	Answer
A	FIR filters can delay all frequency components of the signal by the same amount
B	FIR filters can respond faster to impulses
C	All these choices are correct
D	FIR filters are easier to implement for a given set of passband rolloff requirements

37. - E7G04

What is meant by the "op-amp input offset voltage"?

Select	Answer
A	The difference between the output voltage of the op-amp and the input voltage required in the immediately following stage
B	The potential between the amplifier input terminals of the op-amp in an open loop condition
C	The output voltage of the op-amp minus its input voltage
D	The differential input voltage needed to bring the open loop output voltage to zero

38. - E7H09

What type of frequency synthesizer circuit uses a phase accumulator, lookup table, digital to analog converter, and a low-pass anti-alias filter?

Select	Answer
A	A phase-locked loop synthesizer
B	A direct digital synthesizer
C	A diode-switching matrix synthesizer
D	A hybrid synthesizer

39. - E8A11

Which of the following is a measure of the quality of an analog-to-digital converter?

Select	Answer
A	Total harmonic distortion
B	Power factor
C	Reciprocal mixing
D	Peak envelope power

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 audio modulating frequency to the center carrier frequency
D	The ratio of the carrier center frequency to the audio modulating frequency

41. - E8C02

What is the definition of symbol rate in a digital transmission?

Select	Answer
A	The number of characters carried per second by the station-to-station link
B	The duration of each bit in a message sent over the air
C	The rate at which the waveform changes to convey information
D	The number of control characters in a message packet

42. - E8D04

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

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

43. - E9A13

What term describes station output, taking into account all gains and losses?

Select	Answer
A	Power factor
B	Effective radiated power
C	Half-power bandwidth
D	Apparent power

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

45. - E9C07

What is the approximate feed point impedance at the center of a two-wire folded dipole antenna?

Select	Answer
A	50 ohms
B	450 ohms
C	72 ohms
D	300 ohms

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

47. - E9E08

What is a use for a Wilkinson divider?

Select	Answer
A	It is used to feed low-impedance loads from a high-impedance source
B	It is used to divide power equally between two 50-ohm loads while maintaining 50-ohm input impedance
C	It divides the operating frequency of a transmitter signal so it can be used on a lower frequency band
D	It is used to feed high-impedance antennas from a low-impedance source

48. - E9F10

What impedance does a 1/8-wavelength transmission line present to a generator when the line is shorted at the far end?

Select	Answer
A	An inductive reactance
B	Zero
C	The same as the characteristic impedance of the line
D	A capacitive reactance

49. - E9G05

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

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

50. - E9H03

What is Receiving Directivity Factor (RDF)?

Select	Answer
A	Relative directivity compared to a dipole
B	Forward gain compared to average gain over the entire hemisphere
C	Forward gain compared to the gain in the reverse direction
D	Relative directivity compared to isotropic

Figure E6-1