US Amateur Radio - Amateur Extra (Element 4, 2016-2020) Practice Test

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1. - E1A06

Where must the carrier frequency of a CW signal be set to comply with FCC rules for 60 meter operation?

Select	Answer
A	At the highest frequency of the channel
B	On any frequency where the signal's sidebands are within the channel
C	At the lowest frequency of the channel
D	At the center frequency of the channel

2. - E1B02

Which of the following factors might cause the physical location of an amateur station apparatus or antenna structure to be restricted?

Select	Answer
A	The location is near an area of political conflict
B	The location is of environmental importance or significant in American history, architecture, or culture
C	The location is of geographical or horticultural importance
D	The location is in an ITU Zone designated for coordination with one or more foreign governments

3. - E1C05

When may an automatically controlled station originate third party communications?

Select	Answer
A	Never
B	When approved by the National Telecommunication and Information Administration
C	When agreed upon by the sending or receiving station
D	Only when transmitting RTTY or data emissions

4. - E1D08

Which VHF amateur service bands have frequencies available for space stations?

Select	Answer
A	6 meters and 2 meters
B	2 meters and 1.25 meters
C	6 meters, 2 meters, and 1.25 meters
D	2 meters

5. - E1E01

What is the minimum number of qualified VEs required to administer an Element 4 amateur operator license examination?

Select	Answer
A	4
B	2
C	5
D	3

6. - E1F10

What is the maximum permitted transmitter peak envelope power for an amateur station transmitting spread spectrum communications?

Select	Answer
A	10 W
B	1.5 kW
C	1 W
D	1.5 W

7. - E2A14

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

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

8. - E2B11

What is the function of the Vertical Interval Signaling (VIS) code sent as part of an SSTV transmission?

Select	Answer
A	To lock the color burst oscillator in color SSTV images
B	To identify the SSTV mode being used
C	To provide vertical synchronization
D	To identify the call sign of the station transmitting

9. - E2C06

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

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

10. - E2D01

Which of the following digital modes is especially designed for use for meteor scatter signals?

Select	Answer
A	APRS
B	WSPR
C	Hellschreiber
D	FSK441

11. - E2E07

What is the typical bandwidth of a properly modulated MFSK16 signal?

Select	Answer
A	550 Hz
B	31 Hz
C	2.16 kHz
D	316 Hz

12. - E3A02

What characterizes libration fading of an EME signal?

Select	Answer
A	The returning echo is several Hertz lower in frequency than the transmitted signal
B	A gradual loss of signal as the Sun rises
C	A fluttery irregular fading
D	A slow change in the pitch of the CW signal

13. - E3B05

Which amateur bands typically support long-path propagation?

Select	Answer
A	30 meters to 10 meters
B	6 meters to 2 meters
C	160 meters to 10 meters
D	160 meters to 40 meters

14. - E3C13

What type of polarization is best for ground-wave propagation?

Select	Answer
A	Elliptical
B	Vertical
C	Circular
D	Horizontal

15. - E4A12

Which of the following procedures is an important precaution to follow when connecting a spectrum analyzer to a transmitter output?

Select	Answer
A	Match the antenna to the load
B	Use high quality double shielded coaxial cables to reduce signal losses
C	Attenuate the transmitter output going to the spectrum analyzer
D	All of these choices are correct

16. - E4B02

What is an advantage of using a bridge circuit to measure impedance?

Select	Answer
A	It is relatively immune to drift in the signal generator source
B	It can display results directly in Smith chart format
C	It is very precise in obtaining a signal null
D	It provides an excellent match under all conditions

17. - E4C03

What is the term for the blocking of one FM phone signal by another, stronger FM phone signal?

Select	Answer
A	Frequency discrimination
B	Capture effect
C	Cross-modulation interference
D	Desensitization

18. - E4D12

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

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

19. - E4E05

How can noise from an electric motor be suppressed?

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

20. - E5A08

What is the phase relationship between the current through and the voltage across a series resonant circuit at resonance?

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

21. - E5B02

What is the term for the time it takes for a charged capacitor in an RC circuit to discharge to 36.8% of its initial voltage?

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

22. - E5C13

What coordinate system is often used to display the resistive, inductive, and/or capacitive reactance components of impedance?

Select	Answer
A	Rectangular coordinates
B	Elliptical coordinates
C	Faraday grid
D	Maidenhead grid

23. - E5D10

How can the true power be determined in an AC circuit where the voltage and current are out of phase?

Select	Answer
A	By dividing the reactive power by the power factor
B	By multiplying the reactive power times the power factor
C	By multiplying the apparent power times the power factor
D	By dividing the apparent power by the power factor

24. - E6A16

What are the majority charge carriers in N-type semiconductor material?

Select	Answer
A	Holes
B	Free protons
C	Free neutrons
D	Free electrons

25. - 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	Much higher reverse voltage breakdown
B	Enhanced carrier retention time
C	Controlled reverse avalanche voltage
D	Less forward voltage drop

26. - E6C13

Which of the following is an advantage of BiCMOS logic?

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

27. - E6D09

What devices are commonly used as VHF and UHF parasitic suppressors at the input and output terminals of a transistor HF amplifier?

Select	Answer
A	Ferrite beads
B	Butterworth filters
C	Steel-core toroids
D	Electrolytic capacitors

28. - E6E07

Which of the following is typically used to construct a MMIC-based microwave amplifier?

Select	Answer
A	Point-to-point construction
B	Ground-plane construction
C	Microstrip construction
D	Wave-soldering construction

29. - E6F01

What is photoconductivity?

Select	Answer
A	The increased conductivity of an illuminated semiconductor
B	The conversion of electromotive energy to photon energy
C	The decreased conductivity of an illuminated semiconductor
D	The conversion of photon energy to electromotive energy

30. - E7A11

What type of logic defines "1" as a high voltage?

Select	Answer
A	Reverse Logic
B	Assertive Logic
C	Positive Logic
D	Negative logic

31. - E7B07

Which of the following is a likely result when a Class C amplifier is used to amplify a single-sideband phone signal?

Select	Answer
A	Signal distortion and excessive bandwidth
B	Reduced intermodulation products
C	Signal inversion
D	Increased overall intelligibility

32. - E7C14

Which mode is most affected by non-linear phase response in a receiver IF filter?

Select	Answer
A	Meteor scatter
B	Video
C	Single-Sideband voice
D	Digital

33. - E7D02

What is one characteristic of a switching electronic voltage regulator?

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

34. - E7E08

What are the principal frequencies that appear at the output of a mixer circuit?

Select	Answer
A	Two and four times the original frequency
B	The sum, difference and square root of the input frequencies
C	The two input frequencies along with their sum and difference frequencies
D	1.414 and 0.707 times the input frequency

35. - E7F06

What is the minimum number of bits required for an analog-to-digital converter to sample a signal with a range of 1 volt at a resolution of 1 millivolt?

Select	Answer
A	10 bits
B	6 bits
C	4 bits
D	8 bits

36. - E7G06

Which of the following is the most appropriate use of an op-amp active filter?

Select	Answer
A	As an audio filter in a receiver
B	As a high-pass filter used to block RFI at the input to receivers
C	For smoothing power supply output
D	As a low-pass filter used between a transmitter and a transmission line

37. - E7H10

What information is contained in the lookup table of a direct digital frequency synthesizer?

Select	Answer
A	The phase relationship between a reference oscillator and the output waveform
B	The synthesizer frequency limits and frequency values stored in the radio memories
C	The amplitude values that represent a sine-wave output
D	The phase relationship between a voltage-controlled oscillator and the output waveform

38. - E8A06

What is the approximate ratio of PEP-to-average power in a typical single-sideband phone signal?

Select	Answer
A	1 to 1
B	100 to 1
C	25 to 1
D	2.5 to 1

39. - E8B03

What is the modulation index of an FM-phone signal having a maximum frequency deviation of 3000 Hz either side of the carrier frequency when the modulating frequency is 1000 Hz?

Select	Answer
A	0.3
B	3000
C	1000
D	3

40. - E8C10

What is an advantage of Gray code in digital communications where symbols are transmitted as multiple bits

Select	Answer
A	It facilitates error detection
B	It increases security
C	It has more possible states than simple binary
D	It has more resolution than simple binary

41. - E8D01

Why are received spread spectrum signals resistant to interference?

Select	Answer
A	The high power used by a spread spectrum transmitter keeps its signal from being easily overpowered
B	Signals not using the spread spectrum algorithm are suppressed in the receiver
C	The receiver is always equipped with a digital blanker
D	If interference is detected by the receiver it will signal the transmitter to change frequencies

42. - E9A15

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	1977 watts
B	286 watts
C	78.7 watts
D	420 watts

43. - E9B02

In the antenna radiation pattern shown in Figure E9-1, what is the front-to-back ratio?

Select	Answer
A	36 dB
B	18 dB
C	24 dB
D	14 dB

44. - E9C01

What is the radiation pattern of two 1/4-wavelength vertical antennas spaced 1/2-wavelength apart and fed 180 degrees out of phase?

Select	Answer
A	A figure-8 oriented along the axis of the array
B	A figure-8 broadside to the axis of the array
C	Omni-directional
D	Cardioid

45. - E9D05

What is a disadvantage of using a multiband trapped antenna?

Select	Answer
A	It is too sharply directional at lower frequencies
B	It might radiate harmonics
C	It must be neutralized
D	It radiates the harmonics and fundamental equally well

46. - E9E06

What is the equivalent lumped-constant network for a hairpin matching system of a 3-element Yagi?

Select	Answer
A	A series capacitor
B	Pi-L-network
C	Pi-network
D	A shunt inductor

47. - E9F04

What is the typical velocity factor for a coaxial cable with solid polyethylene dielectric?

Select	Answer
A	0.10
B	0.66
C	2.70
D	0.30

48. - 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

49. - E9H02

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

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

50. - E0A01

What is the primary function of an external earth connection or ground rod?

Select	Answer
A	Reduce RFI to telephones and home entertainment systems
B	Lightning protection
C	Reduce received noise
D	Reduce RF current flow between pieces of equipment

Figure E9-1