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	Polyethylene
D	Polymorphic silicon

2. - E1A14

Except in some parts of Alaska, what is the maximum power permitted on the 630 meter band?

Select	Answer
A	1 watt EIRP
B	100 watts PEP
C	5 watts EIRP
D	50 watts PEP

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 on all frequencies above 30 MHz
C	The amateur station must cease operation on all frequencies below 30 MHz
D	The amateur station must cease operation

4. - E1C01

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

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

5. - E1D06

What is the maximum permitted transmitter output power when operating a model craft by telecommand?

Select	Answer
A	2 watts
B	5 watts
C	1 watt
D	100 watts

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. - E1F08

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

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

8. - E2A07

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

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

9. - E2B10

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

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

10. - E2C05

What is the function of a DX QSL Manager?

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

11. - E2D01

Which of the following digital modes is designed for meteor scatter communications?

Select	Answer
A	WSPR
B	Hellschreiber
C	APRS
D	MSK144

12. - E2E12

How do ALE stations establish contact?

Select	Answer
A	ALE constantly scans a list of frequencies, activating the radio when the designated call sign is received
B	ALE radios send a constant tone code to establish a frequency for future use
C	ALE radios activate when they hear their signal echoed by back scatter
D	ALE radios monitor an internet site for the frequency they are being paged on

13. - E3A05

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

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

14. - E3B11

At what time of day can sporadic E propagation occur?

Select	Answer
A	Only around sunset
B	Any time
C	Only around sunset and sunrise
D	Only in hours of darkness

15. - E3C01

What does the radio communication term "ray tracing" describe?

Select	Answer
A	The process in which an electronic display presents a pattern
B	Evaluating high voltage sources for x-rays
C	Determining the radiation pattern from an array of antennas
D	Modeling a radio wave's path through the ionosphere

16. - E4A04

How is the compensation of an oscilloscope probe typically adjusted?

Select	Answer
A	A square wave is displayed and the probe is adjusted until the horizontal portions of the displayed wave are as nearly flat as possible
B	A high frequency sine wave is displayed and the probe is adjusted for maximum amplitude
C	A DC voltage standard is displayed and the probe is adjusted until the displayed voltage is accurate
D	A frequency standard is displayed and the probe is adjusted until the deflection time is accurate

17. - E4B06

How much power is being absorbed by the load when a directional power meter connected between a transmitter and a terminating load reads 100 watts forward power and 25 watts reflected power?

Select	Answer
A	25 watts
B	100 watts
C	125 watts
D	75 watts

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 low-pass filter to increase the strength of lower frequency signals
D	The attenuator has a noise filter to suppress interference

19. - E4D09

What is the purpose of the preselector in a communications receiver?

Select	Answer
A	To provide a range of AGC time constants
B	To store often-used frequencies
C	To increase rejection of signals outside the desired band
D	To allow selection of the optimum RF amplifier device

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

21. - E5A11

What is the half-power bandwidth of a resonant circuit that has a resonant frequency of 7.1 MHz and a Q of 150?

Select	Answer
A	157.8 Hz
B	23.67 kHz
C	315.6 Hz
D	47.3 kHz

22. - E5B01

What is the term for the time required for the capacitor in an RC circuit to be charged to 63.2% of the applied voltage or to discharge to 36.8% of its initial voltage?

Select	Answer
A	An exponential rate of one
B	One time constant
C	One exponential period
D	A time factor of one

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 2
B	Point 6
C	Point 4
D	Point 5

24. - E5D07

How many watts are consumed in a circuit having a power factor of 0.71 if the apparent power is 500VA?

Select	Answer
A	704 W
B	355 W
C	252 W
D	1.42 mW

25. - E6A01

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

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

26. - E6B02

What is an important characteristic of a Schottky diode as compared to an ordinary silicon diode when used as a power supply rectifier?

Select	Answer
A	Longer carrier retention time
B	Less forward voltage drop
C	Much higher reverse voltage breakdown
D	More constant reverse avalanche voltage

27. - E6C04

Which of the following is an advantage of BiCMOS logic?

Select	Answer
A	It has the high input impedance of CMOS and the low output impedance of bipolar transistors
B	Its simplicity results in much less expensive devices than standard CMOS
C	All these choices are correct
D	It is immune to electrostatic damage

28. - E6D13

What is the primary cause of inductor self-resonance?

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

29. - E6E03

Which of the following materials is likely to provide the highest frequency of operation when used in MMICs?

Select	Answer
A	Silicon
B	Gallium nitride
C	Silicon nitride
D	Silicon dioxide

30. - E6F08

Why are optoisolators often used in conjunction with solid-state circuits when switching 120 VAC?

Select	Answer
A	Optoisolators provide a low impedance link between a control circuit and a power circuit
B	Optoisolators provide a very high degree of electrical isolation between a control circuit and the circuit being switched
C	Optoisolators provide impedance matching between the control circuit and power circuit
D	Optoisolators eliminate the effects of reflected light in the control circuit

31. - E7A07

What logical operation does a NAND gate perform?

Select	Answer
A	It produces logic 0 at its output only when all inputs are logic 1
B	It produces logic 0 at its output only when all inputs are logic 0
C	It produces logic 0 at its output if some but not all inputs are logic 1
D	It produces logic 1 at its output only when all inputs are logic 1

32. - E7B10

In Figure E7-1, what is the purpose of R1 and R2?

Select	Answer
A	Self bias
B	Voltage divider bias
C	Feedback
D	Load resistors

33. - E7C12

What is one advantage of a Pi-matching network over an L-matching network consisting of a single inductor and a single capacitor?

Select	Answer
A	L-networks cannot perform impedance transformation
B	The Q of Pi-networks can be controlled
C	Pi-networks provide balanced input and output
D	Pi-networks are more stable

34. - E7D12

What is the dropout voltage of an analog voltage regulator?

Select	Answer
A	Maximum that the output voltage may decrease at rated load
B	Maximum output voltage drops when the input voltage is varied over its specified range
C	Minimum input voltage for rated power dissipation
D	Minimum input-to-output voltage required to maintain regulation

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 sensing the change of reactance in the diode with respect to frequency
C	By breakdown of the Zener voltage
D	By rectification and filtering of RF signals

36. - E7F08

What is the function of decimation?

Select	Answer
A	Attenuating the signal
B	Reducing the effective sample rate by removing samples
C	Converting data to binary code decimal form
D	Removing unnecessary significant digits

37. - E7G10

What absolute voltage gain can be expected from the circuit in Figure E7-3 when R1 is 1800 ohms and RF is 68 kilohms?

Select	Answer
A	76
B	0.03
C	38
D	1

38. - E7H07

How can an oscillator's microphonic responses be reduced?

Select	Answer
A	Increase the bias voltage
B	Mechanically isolate the oscillator circuitry from its enclosure
C	Use NP0 capacitors
D	Reduce noise on the oscillator's power supply

39. - E8A10

What is the purpose of a low-pass filter used in conjunction with a digital-to-analog converter?

Select	Answer
A	All these choices are correct
B	Lower the input bandwidth to increase the effective resolution
C	Improve accuracy by removing out-of-sequence codes from the input
D	Remove harmonics from the output caused by the discrete analog levels generated

40. - E8B04

What is the modulation index of an FM-phone signal having a maximum carrier deviation of plus or minus 6 kHz when modulated with a 2 kHz modulating frequency?

Select	Answer
A	6000
B	3
C	2000
D	1/3

41. - E8C11

What is the relationship between symbol rate and baud?

Select	Answer
A	Baud is twice the symbol rate
B	Symbol rate is only used for packet-based modes
C	They are the same
D	Baud is only used for RTTY

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	If interference is detected by the receiver it will signal the transmitter to change frequencies
C	If interference is detected by the receiver it will signal the transmitter to wait until the frequency is clear
D	The frequency of the transmitted signal is changed very rapidly according to a pseudorandom sequence also used by the receiving station

43. - E9A07

What is the effective isotropic radiated power of a repeater station with 200 watts transmitter power output, 2 dB feed line loss, 2.8 dB duplexer loss, 1.2 dB circulator loss, and 7 dBi antenna gain?

Select	Answer
A	159 watts
B	252 watts
C	632 watts
D	63.2 watts

44. - E9B06

What is the elevation angle of peak response in the antenna radiation pattern shown in Figure E9-2?

Select	Answer
A	75 degrees
B	7.5 degrees
C	25 degrees
D	45 degrees

45. - E9C08

What is a folded dipole antenna?

Select	Answer
A	A dipole one-quarter wavelength long
B	A type of ground-plane antenna
C	A dipole configured to provide forward gain
D	A half-wave dipole with an additional parallel wire connecting its two ends

46. - E9D02

How can linearly polarized Yagi antennas be used to produce circular polarization?

Select	Answer
A	Arrange two Yagis perpendicular to each other with the driven elements at the same point on the boom fed 90 degrees out of phase
B	Arrange two Yagis collinear to each other with the driven elements fed 180 degrees out of phase
C	Stack two Yagis fed in phase to form an array with the respective elements in parallel planes
D	Stack two Yagis fed 90 degrees out of phase to form an array with the respective elements in parallel planes

47. - E9E11

What is the primary purpose of phasing lines when used with an antenna having multiple driven elements?

Select	Answer
A	It allows single-band antennas to operate on other bands
B	It creates a low-angle radiation pattern
C	It ensures that each driven element operates in concert with the others to create the desired antenna pattern
D	It prevents reflected power from traveling back down the feed line and causing harmonic radiation from the transmitter

48. - E9F09

What is the approximate physical length of a foam polyethylene dielectric coaxial transmission line that is electrically 1/4 wavelength long at 7.2 MHz?

Select	Answer
A	5.2 meters
B	10.4 meters
C	6.9 meters
D	8.3 meters

49. - E9G10

What do the arcs on a Smith chart represent?

Select	Answer
A	SWR
B	Frequency
C	Points with constant reactance
D	Points with constant resistance

50. - E9H07

Why is RF attenuation used when direction-finding?

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

Figure E5-1

Figure E7-1

Figure E7-3

Figure E9-2