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

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1. - E1A14

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

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

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

3. - E1C10

What types of amateur stations may automatically retransmit the radio signals of other amateur stations?

Select	Answer
A	Only earth stations, repeater stations or model craft
B	Only auxiliary, repeater or space stations
C	Only beacon, repeater or space stations
D	Only auxiliary, beacon or space stations

4. - E1D10

Which amateur stations are eligible to be telecommand stations?

Select	Answer
A	Any amateur station so designated by the ITU
B	Any amateur station designated by NASA
C	All of these choices are correct
D	Any amateur station so designated by the space station licensee, subject to the privileges of the class of operator license held by the control operator

5. - E1E09

What may be the penalty for a VE who fraudulently administers or certifies an examination?

Select	Answer
A	Revocation of the VE's amateur station license grant and the suspension of the VE's amateur operator license grant
B	A sentence of up to one year in prison
C	All of these choices are correct
D	A fine of up to $1000 per occurrence

6. - E1F09

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

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

7. - E2A02

What is the direction of a descending pass for an amateur satellite?

Select	Answer
A	From north to south
B	From west to east
C	From south to north
D	From east to west

8. - E2B01

How many times per second is a new frame transmitted in a fast-scan (NTSC) television system?

Select	Answer
A	90
B	30
C	60
D	120

9. - E2C02

Which of the following best describes the term self-spotting in regards to HF contest operating?

Select	Answer
A	The generally prohibited practice of posting one's own call sign and frequency on a spotting network
B	A manual technique for rapidly zero beating or tuning to a station's frequency before calling that station
C	An automatic method for rapidly zero beating or tuning to a station's frequency before calling that station
D	The acceptable practice of manually posting the call signs of stations on a spotting network

10. - E2D07

What digital protocol is used by APRS?

Select	Answer
A	AX.25
B	PACTOR
C	AMTOR
D	802.11

11. - E2E11

What is the difference between direct FSK and audio FSK?

Select	Answer
A	Direct FSK applies the data signal to the transmitter VFO
B	Audio FSK can be performed anywhere in the transmit chain
C	Direct FSK uses a DC-coupled data connection
D	Audio FSK has a superior frequency response

12. - E3A15

What is an electromagnetic wave?

Select	Answer
A	A wave of alternating current, in the core of an electromagnet
B	A wave consisting of an electric field and a magnetic field oscillating at right angles to each other
C	A wave consisting of two magnetic fields at right angles to each other
D	A wave consisting of two electric fields at parallel right angles to each other

13. - E3B05

Which amateur bands typically support long-path propagation?

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

14. - E3C12

How does the maximum distance of ground-wave propagation change when the signal frequency is increased?

Select	Answer
A	It decreases
B	It stays the same
C	It increases
D	It peaks at roughly 14 MHz

15. - E4A15

What is an advantage of a period-measuring frequency counter over a direct-count type?

Select	Answer
A	It provides improved resolution of low-frequency signals within a comparable time period
B	It can directly measure the modulation index of an FM transmitter
C	It does not require an expensive high-precision time base
D	It can run on battery power for remote measurements

16. - E4B07

What do the subscripts of S parameters represent?

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

17. - E4C01

What is an effect of excessive phase noise in the local oscillator section of a receiver?

Select	Answer
A	It decreases receiver third-order intermodulation distortion dynamic range
B	It reduces receiver sensitivity
C	It limits the receiver's ability to receive strong signals
D	It can cause strong signals on nearby frequencies to interfere with reception of weak signals

18. - E4D09

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

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

19. - E4E07

How can you determine if line noise interference is being generated within your home?

Select	Answer
A	By observing the AC power line waveform with an oscilloscope
B	By observing the AC power line voltage with a spectrum analyzer
C	By checking the power line voltage with a time domain reflectometer
D	By turning off the AC power line main circuit breaker and listening on a battery operated radio

20. - E5A10

How is the Q of an RLC series resonant circuit calculated?

Select	Answer
A	Reactance of either the inductance or capacitance times the resistance
B	Reactance of the inductance times the reactance of the capacitance
C	Resistance divided by the reactance of either the inductance or capacitance
D	Reactance of either the inductance or capacitance divided by the resistance

21. - E5B09

What is the relationship between the current through a capacitor and the voltage across a capacitor?

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

22. - E5C08

What coordinate system is often used to display the phase angle of a circuit containing resistance, inductive and/or capacitive reactance?

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

23. - E5D09

What happens to reactive power in an AC circuit that has both ideal inductors and ideal capacitors?

Select	Answer
A	It is dissipated in the formation of inductive and capacitive fields
B	It is dissipated as heat in the circuit
C	It is dissipated as kinetic energy in the circuit
D	It is repeatedly exchanged between the associated magnetic and electric fields, but is not dissipated

24. - E6A07

Which of the following indicates that a silicon NPN junction transistor is biased on?

Select	Answer
A	Base-to-emitter resistance of approximately 6 to 7 ohms
B	Base-to-emitter resistance of approximately 0.6 to 0.7 ohms
C	Base-to-emitter voltage of approximately 6 to 7 volts
D	Base-to-emitter voltage of approximately 0.6 to 0.7 volts

25. - E6B08

Which of the following describes a type of semiconductor diode?

Select	Answer
A	CMOS-field effect
B	Electrolytic rectifier
C	Metal-semiconductor junction
D	Thermionic emission diode

26. - E6C02

What happens when the level of a comparator's input signal crosses the threshold?

Select	Answer
A	The comparator changes its output state
B	The comparator enters latch-up
C	The feedback loop becomes unstable
D	The IC input can be damaged

27. - E6D08

What is one reason for using powdered-iron cores rather than ferrite cores in an inductor?

Select	Answer
A	Powdered-iron cores use smaller diameter wire for the same inductance
B	Powdered-iron cores generally have greater initial permeability
C	Powdered-iron cores generally require fewer turns to produce a given inductance
D	Powdered-iron cores generally maintain their characteristics at higher currents

28. - E6E06

What characteristics of the MMIC make it a popular choice for VHF through microwave circuits?

Select	Answer
A	Plate current that is controlled by a control grid
B	Controlled gain, low noise figure, and constant input and output impedance over the specified frequency range
C	The ability to retrieve information from a single signal even in the presence of other strong signals
D	Nearly infinite gain, very high input impedance, and very low output impedance

29. - E6F14

Which of the following is true of LCD displays?

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

30. - E7A09

What logical operation is performed by an exclusive NOR gate?

Select	Answer
A	It produces logic "0" at its output if any single input is logic "1"
B	It produces logic "1" at its output only if all inputs are logic "1"
C	It produces logic "0" at its output only if all inputs are logic "0"
D	It produces logic "1" at its output if any single input is logic "1"

31. - E7B05

What can be done to prevent unwanted oscillations in an RF power amplifier?

Select	Answer
A	Tune both the input and output for maximum power
B	Use a phase inverter in the output filter
C	Tune the stage for maximum SWR
D	Install parasitic suppressors and/or neutralize the stage

32. - E7C07

What kind of filter would you use to attenuate an interfering carrier signal while receiving an SSB transmission?

Select	Answer
A	An all-pass filter
B	A notch filter
C	A band-pass filter
D	A Pi-network filter

33. - E7D11

What circuit element is controlled by a series analog voltage regulator to maintain a constant output voltage?

Select	Answer
A	Reference voltage
B	Pass transistor
C	Error amplifier
D	Switching inductance

34. - E7E12

What is a frequency discriminator stage in a FM receiver?

Select	Answer
A	An FM generator circuit
B	A circuit for detecting FM signals
C	A circuit for filtering two closely adjacent signals
D	An automatic band-switching circuit

35. - E7F14

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

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

36. - E7G06

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

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

37. - E7H10

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

Select	Answer
A	The synthesizer frequency limits and frequency values stored in the radio memories
B	The amplitude values that represent a sine-wave output
C	The phase relationship between a voltage-controlled oscillator and the output waveform
D	The phase relationship between a reference 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	25 to 1
B	1 to 1
C	2.5 to 1
D	100 to 1

39. - E8B11

What is digital time division multiplexing?

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

40. - E8C05

What is the necessary bandwidth of a 13-WPM international Morse code transmission?

Select	Answer
A	Approximately 13 Hz
B	Approximately 52 Hz
C	Approximately 26 Hz
D	Approximately 104 Hz

41. - E8D06

Which of the following indicates likely overmodulation of an AFSK signal such as PSK or MFSK?

Select	Answer
A	Harmonics on higher bands
B	Strong ALC action
C	High reflected power
D	Rapid signal fading

42. - E9A13

How much gain does an antenna have compared to a 1/2-wavelength dipole when it has 12 dB gain over an isotropic antenna?

Select	Answer
A	14.15 dB
B	12.5 dB
C	6.17 dB
D	9.85 dB

43. - E9B09

What type of computer program technique is commonly used for modeling antennas?

Select	Answer
A	Method of Moments
B	Mutual impedance analysis
C	Graphical analysis
D	Calculus differentiation with respect to physical properties

44. - E9C08

What is a folded dipole antenna?

Select	Answer
A	A dipole consisting of one wavelength of wire forming a very thin loop
B	A type of ground-plane antenna
C	A dipole one-quarter wavelength long
D	A dipole configured to provide forward gain

45. - E9D12

Which of the following would provide the best RF ground for your station?

Select	Answer
A	A 50 ohm resistor connected to ground
B	An electrically short connection to 3 or 4 interconnected ground rods via a series RF choke
C	An electrically short connection to 3 or 4 interconnected ground rods driven into the Earth
D	An electrically short connection to a metal water pipe

46. - E9E10

Which of these choices is an effective way to match an antenna with a 100 ohm feed point impedance to a 50 ohm coaxial cable feed line?

Select	Answer
A	Insert a 1/4-wavelength piece of 75 ohm coaxial cable transmission line in series between the antenna terminals and the 50 ohm feed cable
B	Insert a 1/2 wavelength piece of 300 ohm twin-lead in series between the antenna terminals and the 50 ohm feed cable
C	Connect 1/2 wavelength shorted stub of 75 ohm cable in parallel with the 50 ohm cable where it attaches to the antenna
D	Connect a 1/4-wavelength open stub of 300 ohm twin-lead in parallel with the coaxial feed line where it connects to the antenna

47. - 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	The same as the input impedance to the final generator stage
B	An inductive reactance
C	A capacitive reactance
D	The same as the characteristic impedance of the line

48. - E9G01

Which of the following can be calculated using a Smith chart?

Select	Answer
A	Radio propagation
B	Antenna radiation pattern
C	Radiation resistance
D	Impedance along transmission lines

49. - E9H01

When constructing a Beverage antenna, which of the following factors should be included in the design to achieve good performance at the desired frequency?

Select	Answer
A	Its overall length must not exceed 1/4 wavelength
B	It must be mounted more than 1 wavelength above ground
C	It should be configured as a four-sided loop
D	It should be one or more wavelengths long

50. - E0A03

Which of the following would be a practical way to estimate whether the RF fields produced by an amateur radio station are within permissible MPE limits?

Select	Answer
A	Use a calibrated antenna analyzer
B	Use a hand calculator plus Smith-chart equations to calculate the fields
C	Use an antenna modeling program to calculate field strength at accessible locations
D	All of the choices are correct