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

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1. - E1A10

If an amateur station is installed aboard a ship or aircraft, what condition must be met before the station is operated?

Select	Answer
A	The amateur operator must have an FCC Marine or Aircraft endorsement on his or her amateur license
B	The amateur station operator must agree not to transmit when the main radio of the ship or aircraft is in use
C	Its operation must be approved by the master of the ship or the pilot in command of the aircraft
D	The amateur station must have a power supply that is completely independent of the main ship or aircraft power supply

2. - E1B01

Which of the following constitutes a spurious emission?

Select	Answer
A	A signal transmitted to prevent its detection by any station other than the intended recipient
B	Any transmitted signal that unintentionally interferes with another licensed radio station
C	An amateur station transmission made at random without the proper call sign identification
D	An emission outside its necessary bandwidth that can be reduced or eliminated without affecting the information transmitted

3. - E1C12

What types of communications may be transmitted to amateur stations in foreign countries?

Select	Answer
A	Communications incidental to the purpose of the amateur service and remarks of a personal nature
B	All of these choices are correct
C	Business-related messages for non-profit organizations
D	Messages intended for connection to users of the maritime satellite service

4. - E1D04

What is an Earth station in the amateur satellite service?

Select	Answer
A	An amateur station that transmits telemetry consisting of measurement of upper atmosphere
B	An amateur station within 50 km of the Earth's surface intended for communications with amateur stations by means of objects in space
C	An amateur station that is not able to communicate using amateur satellites
D	Any amateur station on the surface of the Earth

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

6. - E1F01

On what frequencies are spread spectrum transmissions permitted?

Select	Answer
A	Only on amateur frequencies above 50 MHz
B	Only on amateur frequencies above 420 MHz
C	Only on amateur frequencies above 144 MHz
D	Only on amateur frequencies above 222 MHz

7. - E2A12

What is one way to predict the location of a satellite at a given time?

Select	Answer
A	By adding the mean anomaly to the orbital inclination
B	By means of the Doppler data for the specified satellite
C	By subtracting the mean anomaly from the orbital inclination
D	By calculations using the Keplerian elements for the specified satellite

8. - E2B12

How are analog SSTV images typically transmitted on the HF bands?

Select	Answer
A	Varying tone frequencies representing the video are transmitted using PSK
B	Video is converted to equivalent Baudot representation
C	Varying tone frequencies representing the video are transmitted using single sideband
D	Video is converted to equivalent ASCII representation

9. - E2C09

What type of equipment is commonly used to implement a ham radio mesh network?

Select	Answer
A	A 2 meter VHF transceiver with a 1200 baud modem
B	An optical cable connection between the USB ports of 2 separate computers
C	A 440 MHz transceiver with a 9600 baud modem
D	A standard wireless router running custom software

10. - E2D09

Which of these digital modes has the fastest data throughput under clear communication conditions?

Select	Answer
A	300 baud packet
B	170 Hz shift, 45 baud RTTY
C	AMTOR
D	PSK31

11. - E2E09

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

Select	Answer
A	RTTY
B	PSK31
C	PACTOR
D	MT63

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 two electric fields at parallel right angles to each other
C	A wave consisting of an electric field and a magnetic field oscillating at right angles to each other
D	A wave consisting of two magnetic fields at right angles to each other

13. - E3B10

What is the cause of gray-line propagation?

Select	Answer
A	In darkness, solar absorption drops greatly while atmospheric ionization remains steady
B	At twilight and sunrise, D-layer absorption is low while E-layer and F-layer propagation remains high
C	At mid-afternoon, the Sun heats the ionosphere decreasing radio wave refraction and the MUF
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	Twice as great
B	Four times as great
C	50 percent greater
D	10 percent greater

15. - E4A04

What determines the upper frequency limit for a computer soundcard-based oscilloscope program?

Select	Answer
A	All of these choices are correct
B	Amount of memory on the soundcard
C	Analog-to-digital conversion speed of the soundcard
D	Q of the interface of the interface circuit

16. - E4B09

What is indicated if the current reading on an RF ammeter placed in series with the antenna feed line of a transmitter increases as the transmitter is tuned to resonance?

Select	Answer
A	There is possibly a short to ground in the feed line
B	The transmitter is not properly neutralized
C	There is more power going into the antenna
D	There is an impedance mismatch between the antenna and feed line

17. - E4C05

What does a value of -174 dBm/Hz represent with regard to the noise floor of a receiver?

Select	Answer
A	The minimum detectable signal as a function of receive frequency
B	The noise figure of a 1 Hz bandwidth receiver
C	The galactic noise contribution to minimum detectable signal
D	The theoretical noise at the input of a perfect receiver at room temperature

18. - E4D03

How can intermodulation interference between two repeaters occur?

Select	Answer
A	When the repeaters are in close proximity and the signals cause feedback in the final amplifier of one or both transmitters
B	When the signals from the transmitters are reflected out of phase from airplanes passing overhead
C	When the signals from the transmitters are reflected in phase from airplanes passing overhead
D	When the repeaters are in close proximity and the signals mix in the final amplifier of one or both transmitters

19. - E4E09

What undesirable effect can occur when using an IF noise blanker?

Select	Answer
A	The audio frequency bandwidth of the received signal might be compressed
B	Received audio in the speech range might have an echo effect
C	FM signals can no longer be demodulated
D	Nearby signals may appear to be excessively wide even if they meet emission standards

20. - E5A16

What is the resonant frequency of a parallel RLC circuit if R is 33 ohms, L is 50 microhenrys and C is 10 picofarads?

Select	Answer
A	23.5 kHz
B	7.12 kHz
C	23.5 MHz
D	7.12 MHz

21. - E5B11

What is the phase angle between the voltage across and the current through a series RLC circuit if XC is 25 ohms, R is 100 ohms, and XL is 50 ohms?

Select	Answer
A	14 degrees with the voltage lagging the current
B	76 degrees with the voltage lagging the current
C	76 degrees with the voltage leading the current
D	14 degrees with the voltage leading the current

22. - E5C03

Which of the following represents an inductive reactance in polar coordinates?

Select	Answer
A	A negative phase angle
B	A positive phase angle
C	A positive real part
D	A negative real part

23. - E5D07

What determines the strength of the magnetic field around a conductor?

Select	Answer
A	The diameter of the conductor
B	The resistance divided by the current
C	The ratio of the current to the resistance
D	The amount of current flowing through the conductor

24. - E6A04

What is the name given to an impurity atom that adds holes to a semiconductor crystal structure?

Select	Answer
A	Insulator impurity
B	Donor impurity
C	N-type impurity
D	Acceptor impurity

25. - E6B10

In Figure E6-3, what is the schematic symbol for a light-emitting diode?

Select	Answer
A	1
B	7
C	5
D	6

26. - E6C06

Why do CMOS digital integrated circuits have high immunity to noise on the input signal or power supply?

Select	Answer
A	The input switching threshold is about two times the power supply voltage
B	Larger bypass capacitors are used in CMOS circuit design
C	Input signals are stronger
D	The input switching threshold is about one-half the power supply voltage

27. - E6D03

Which of the following is an aspect of the piezoelectric effect?

Select	Answer
A	Increased conductivity in the presence of light
B	Mechanical deformation of material by the application of a magnetic field
C	Generation of electrical energy in the presence of light
D	Mechanical deformation of material by the application of a voltage

28. - E6E09

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

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

29. - E6F12

What absorbs the energy from light falling on a photovoltaic cell?

Select	Answer
A	Photons
B	Holes
C	Protons
D	Electrons

30. - E7A10

What is a truth table?

Select	Answer
A	A list of inputs and corresponding outputs for a digital device
B	A table of logic symbols that indicate the logic states of an op-amp
C	A table of logic symbols that indicate the high logic states of an op-amp
D	A diagram showing logic states when the digital device output is true

31. - E7B16

What is the effect of intermodulation products in a linear power amplifier?

Select	Answer
A	Transmission of spurious signals
B	Creation of parasitic oscillations
C	Low efficiency
D	All of these choices are correct

32. - 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	Extremely sharp cutoff with one or more notches in the stop band
C	Gradual passband rolloff with minimal stop band ripple
D	Gradual passband rolloff with extreme stop band ripple

33. - E7D14

What is one purpose of a "bleeder" resistor in a conventional unregulated power supply?

Select	Answer
A	To balance the low-voltage filament windings
B	To improve output voltage regulation
C	To boost the amount of output current
D	To cut down on waste heat generated by the power supply

34. - E7E12

What is a frequency discriminator stage in a FM receiver?

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

35. - E7F10

What aspect of receiver analog-to-digital conversion determines the maximum receive bandwidth of a Direct Digital Conversion SDR?

Select	Answer
A	Sample rate
B	Sample width in bits
C	Sample clock phase noise
D	Processor latency

36. - E7G05

How can unwanted ringing and audio instability be prevented in a multi-section op-amp RC audio filter circuit?

Select	Answer
A	Restrict gain but increase Q
B	Increase both gain and Q
C	Restrict Q but increase gain
D	Restrict both gain and Q

37. - E7H07

How can an oscillator's microphonic responses be reduced?

Select	Answer
A	Use of NP0 capacitors
B	Using the oscillator only for CW and digital signals
C	Mechanically isolating the oscillator circuitry from its enclosure
D	Eliminating noise on the oscillator's power supply

38. - E8A03

What type of wave does a Fourier analysis show to be made up of sine waves of a given fundamental frequency plus all of its harmonics?

Select	Answer
A	A square wave
B	A cosine wave
C	A sine wave
D	A sawtooth wave

39. - 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	2000
B	3
C	1/3
D	6000

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 has more possible states than simple binary
C	It has more resolution than simple binary
D	It increases security

41. - E8D01

Why are received spread spectrum signals resistant to interference?

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

42. - E9A07

What is meant by antenna gain?

Select	Answer
A	The ratio of the signal in the forward direction to that in the opposite direction
B	The ratio of the amount of power radiated by an antenna compared to the transmitter output power
C	The final amplifier gain minus the transmission line losses
D	The ratio of the radiated signal strength of an antenna in the direction of maximum radiation to that of a reference antenna

43. - E9B07

How does the total amount of radiation emitted by a directional gain antenna compare with the total amount of radiation emitted from an 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 total amount of radiation from the directional antenna is stronger by its front-to-back ratio
C	They are the same
D	The radiation from the isotropic antenna is 2.15 dB stronger than that from the directional antenna

44. - E9C06

What is the effect of a terminating resistor on a rhombic antenna?

Select	Answer
A	It reflects the standing waves on the antenna elements back to the transmitter
B	It changes the radiation pattern from bidirectional to unidirectional
C	It changes the radiation pattern from horizontal to vertical polarization
D	It decreases the ground loss

45. - E9D01

How does the gain of an ideal parabolic dish antenna change when the operating frequency is doubled?

Select	Answer
A	Gain is multiplied by 0.707
B	Gain does not change
C	Gain increases by 6 dB
D	Gain increases by 3 dB

46. - E9E06

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

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

47. - E9F03

Why is the physical length of a coaxial cable transmission line shorter than its electrical length?

Select	Answer
A	Skin effect is less pronounced in the coaxial cable
B	The surge impedance is higher in a parallel feed line
C	Electrical signals move more slowly in a coaxial cable than in air
D	The characteristic impedance is higher in a parallel feed line

48. - E9G04

What are the two families of circles and arcs that make up a Smith chart?

Select	Answer
A	Resistance and reactance
B	Voltage and impedance
C	Resistance and voltage
D	Reactance and voltage

49. - E9H04

What is an advantage of using a shielded loop antenna for direction finding?

Select	Answer
A	It automatically cancels ignition noise in mobile installations
B	It eliminates tracking errors caused by strong out-of-band signals
C	It is electro statically balanced against ground, giving better nulls
D	It allows stations to communicate without giving away their position

50. - E0A01

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

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

Figure E6-3