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

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1. - E1A03

With your transceiver displaying the carrier frequency of phone signals, you hear a station calling CQ on 14.349 MHz USB. Is it legal to return the call using upper sideband on the same frequency?

Select	Answer
A	No, the sideband will extend beyond the band edge
B	Yes, because the displayed frequency is within the 20 meter band
C	No, U.S. stations are not permitted to use phone emissions above 14.340 MHz
D	Yes, because you were not the station calling CQ

2. - E1B09

Which amateur stations may be operated under RACES rules?

Select	Answer
A	Any FCC-licensed amateur station except a Technician class
B	Only those club stations licensed to Amateur Extra class operators
C	Any FCC-licensed amateur station certified by the responsible civil defense organization for the area served
D	Any FCC-licensed amateur station participating in the Military Auxiliary Radio System (MARS)

3. - E1C06

Which of the following statements concerning remotely controlled amateur stations is true?

Select	Answer
A	Only Extra Class operators may be the control operator of a remote station
B	A control operator need not be present at the control point
C	A control operator must be present at the control point
D	Repeater and auxiliary stations may not be remotely controlled

4. - E1D05

What class of licensee is authorized to be the control operator of a space station?

Select	Answer
A	Any class with appropriate operator privileges
B	Only General, Advanced or Amateur Extra Class
C	All except Technician Class
D	Only Amateur Extra Class

5. - E1E10

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

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

6. - E1F09

Which of the following conditions apply when transmitting spread spectrum emission?

Select	Answer
A	A station transmitting SS emission must not cause harmful interference to other stations employing other authorized emissions
B	The transmission must not be used to obscure the meaning of any communication
C	All of these choices are correct
D	The transmitting station must be in an area regulated by the FCC or in a country that permits SS emissions

7. - E2A06

On what band would a satellite receive signals if it were operating in mode U/V?

Select	Answer
A	50.0 MHz - 50.2 MHz
B	29.5 MHz - 29.7 MHz
C	144 MHz - 146 MHz
D	435 MHz - 438 MHz

8. - E2B06

What is vestigial sideband modulation?

Select	Answer
A	Narrow-band FM modulation achieved by filtering one sideband from the audio before frequency modulating the carrier
B	Spread spectrum modulation achieved by applying FM modulation following single sideband amplitude modulation
C	Amplitude modulation in which one complete sideband and a portion of the other are transmitted
D	A type of modulation in which one sideband is inverted

9. - E2C08

Which of the following contacts may be confirmed through the U.S. QSL bureau system?

Select	Answer
A	Special event contacts between stations in the U.S.
B	Repeater contacts between U.S. club members
C	Contacts using tactical call signs
D	Contacts between a U.S. station and a non-U.S. station

10. - E2D03

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

Select	Answer
A	Olivia
B	FSK441
C	JT65
D	PACTOR III

11. - E2E05

Which type of digital mode does not support keyboard-to-keyboard operation?

Select	Answer
A	RTTY
B	MFSK
C	Winlink
D	PSK31

12. - E3A14

From the contiguous 48 states, in which approximate direction should an antenna be pointed to take maximum advantage of aurora propagation?

Select	Answer
A	North
B	East
C	West
D	South

13. - E3B10

What is the cause of gray-line propagation?

Select	Answer
A	At mid-afternoon, the Sun heats the ionosphere decreasing radio wave refraction and the MUF
B	At twilight and sunrise, D-layer absorption is low while E-layer and F-layer propagation remains high
C	In darkness, solar absorption drops greatly while atmospheric ionization remains steady
D	At midday, the Sun super heats the ionosphere causing increased refraction of radio waves

14. - E3C09

How does the intensity of an X3 flare compare to that of an X2 flare?

Select	Answer
A	Four times as great
B	50 percent greater
C	Twice as great
D	10 percent greater

15. - E4A09

When using a computer's soundcard input to digitize signals, what is the highest frequency signal that can be digitized without aliasing?

Select	Answer
A	The same as the sample rate
B	It depends on how the data is stored internally
C	One-half the sample rate
D	One-tenth the sample rate

16. - E4B07

What do the subscripts of S parameters represent?

Select	Answer
A	Frequency order of the measurements
B	The relative time between measurements
C	Relative quality of the data
D	The port or ports at which measurements are made

17. - E4C12

What is an undesirable effect of using too wide a filter bandwidth in the IF section of a receiver?

Select	Answer
A	Filter ringing
B	Output-offset overshoot
C	Thermal-noise distortion
D	Undesired signals may be heard

18. - E4D01

What is meant by the blocking dynamic range of a receiver?

Select	Answer
A	The difference in dB between the noise floor and the level of an incoming signal which will cause 1 dB of gain compression
B	The difference in dB between the noise floor and the third order intercept point
C	The minimum difference in dB between two signals which produce third order intermodulation products greater than the noise floor
D	The minimum difference in dB between the levels of two FM signals which will cause one signal to block the other

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 using a ground-fault current interrupter in the circuit used to power the motor
C	By installing a bypass capacitor in series with the motor leads
D	By installing a brute-force AC-line filter in series with the motor leads

20. - E5A11

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

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

21. - E5B13

What letter is commonly used to represent susceptance?

Select	Answer
A	G
B	Y
C	B
D	X

22. - E5C10

When using rectangular coordinates to graph the impedance of a circuit, what does the vertical axis represent?

Select	Answer
A	Resistive component
B	The sum of the reactive and resistive components
C	Reactive component
D	The difference between the resistive and reactive components

23. - E5D16

What is the power factor of an R-L circuit having a 30 degree phase angle between the voltage and the current?

Select	Answer
A	0.866
B	0.5
C	1.73
D	0.577

24. - E6A12

Why do many MOSFET devices have internally connected Zener diodes on the gates?

Select	Answer
A	To protect the substrate from excessive voltages
B	To provide a voltage reference for the correct amount of reverse-bias gate voltage
C	To reduce the chance of the gate insulation being punctured by static discharges or excessive voltages
D	To keep the gate voltage within specifications and prevent the device from overheating

25. - E6B07

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

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

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 is totally immune to electrostatic damage
C	It has the high input impedance of CMOS and the low output impedance of bipolar transistors
D	All of these choices are correct

27. - E6D13

What is the primary cause of inductor self-resonance?

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

28. - 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	Surface mount
C	Radial lead
D	Axial lead

29. - E6F14

Which of the following is true of LCD displays?

Select	Answer
A	They are hard to view in high ambient light conditions
B	They only display alphanumeric symbols
C	All of these choices are correct
D	They may be hard view through polarized lenses

30. - 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 "0" at its output if any single input is logic "1"
C	It produces logic "1" at its output if any single input is logic "1"
D	It produces logic "0" at its output only if all inputs are logic "0"

31. - E7B06

Which of the following amplifier types reduces or eliminates even order harmonics?

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

32. - E7C01

How are the capacitors and inductors of a low-pass filter Pi-network arranged between the network's input and output?

Select	Answer
A	An inductor is connected between the input and ground, another inductor is connected between the output and ground, and a capacitor is connected between the input and output
B	Two inductors are in series between the input and output, and a capacitor is connected between the two inductors and ground
C	Two capacitors are in series between the input and output, and an inductor is connected between the two capacitors and ground
D	A capacitor is connected between the input and ground, another capacitor is connected between the output and ground, and an inductor is connected between input and output

33. - E7D15

What is the purpose of a "step-start" circuit in a high voltage power supply?

Select	Answer
A	To allow the filter capacitors to charge gradually
B	To compensate for variations of the incoming line voltage
C	To provide a dual-voltage output for reduced power applications
D	To allow for remote control of the power supply

34. - E7E06

Why is de-emphasis commonly used in FM communications receivers?

Select	Answer
A	To reduce impulse noise reception
B	To remove third-order distortion products
C	For compatibility with transmitters using phase modulation
D	For higher efficiency

35. - E7F13

What is the function of taps in a digital signal processing filter?

Select	Answer
A	Provide access for debugging software
B	To reduce excess signal pressure levels
C	Select the point at which baseband signals are generated
D	Provide incremental signal delays for filter algorithms

36. - E7G06

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

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

37. - E7H12

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

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

38. - 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

39. - E8B11

What is digital time division multiplexing?

Select	Answer
A	Two or more data streams share the same channel by transmitting time of transmission as the sub-carrier
B	Two or more data streams are assigned to discrete sub-carriers on an FM transmitter
C	Two or more signals are quadrature modulated to increase bandwidth efficiency
D	Two or more signals are arranged to share discrete time slots of a data transmission

40. - E8C11

What is the relationship between symbol rate and baud?

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

41. - 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 RF harmonics
C	The generation of key clicks
D	More difficult to copy

42. - E9A11

Which of the following factors determines ground losses for a ground-mounted vertical antenna operating in the 3 MHz to 30 MHz range?

Select	Answer
A	Take-off angle
B	The standing wave ratio
C	Soil conductivity
D	Distance from the transmitter

43. - E9B02

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

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

44. - 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 consisting of one wavelength of wire forming a very thin loop
D	A dipole configured to provide forward gain

45. - E9D09

What is the function of a loading coil used as part of an HF mobile antenna?

Select	Answer
A	To cancel capacitive reactance
B	To lower the Q
C	To lower the losses
D	To increase the SWR bandwidth

46. - E9E13

What is a use for a Wilkinson divider?

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

47. - E9F07

How does ladder line compare to small-diameter coaxial cable such as RG-58 at 50 MHz?

Select	Answer
A	Higher SWR
B	Smaller reflection coefficient
C	Lower loss
D	Lower velocity factor

48. - E9G08

What is the process of normalization with regard to a Smith chart?

Select	Answer
A	Reassigning reactance values with regard to the resistance axis
B	Reassigning impedance values with regard to the prime center
C	Reassigning resistance values with regard to the reactance axis
D	Reassigning prime center with regard to the reactance axis

49. - E9H10

How can the output voltage of a multiple turn receiving loop antenna be increased?

Select	Answer
A	By winding adjacent turns in opposing directions
B	By increasing the number of wire turns in the loop and reducing the area of the loop structure
C	By reducing the permeability of the loop shield
D	By increasing either the number of wire turns in the loop or the area of the loop structure or both

50. - E0A11

Which of the following injuries can result from using high-power UHF or microwave transmitters?

Select	Answer
A	Ingestion of ozone gas from the cooling system
B	Localized heating of the body from RF exposure in excess of the MPE limits
C	Blood clotting from the intense magnetic field
D	Hearing loss caused by high voltage corona discharge

Figure E9-1