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

2. - E1B05

What is the National Radio Quiet Zone?

Select	Answer
A	An area in Puerto Rico surrounding the Arecibo Radio Telescope
B	An area in New Mexico surrounding the White Sands Test Area
C	An area in Florida surrounding Cape Canaveral
D	An area surrounding the National Radio Astronomy Observatory

3. - E1C02

What is meant by automatic control of a station?

Select	Answer
A	A station operating with its output power controlled automatically
B	The use of a control link between a control point and a locally controlled station
C	Remotely controlling a station's antenna pattern through a directional control link
D	The use of devices and procedures for control so that the control operator does not have to be present at a control point

4. - E1D05

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

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

5. - E1E13

Which of these choices is an acceptable method for monitoring the applicants if a VEC opts to conduct an exam session remotely?

Select	Answer
A	Have each applicant sign an affidavit stating that all session rules were followed
B	The exam proctor observes the applicants and reports any violations
C	Use a real-time video link and the Internet to connect the exam session to the observing VEs
D	Record the exam session on video tape for later review by the VE team

6. - E1F12

Who may be the control operator of an auxiliary station?

Select	Answer
A	Only General, Advanced or Amateur Extra Class operators
B	Only Amateur Extra Class operators
C	Only Technician, General, Advanced or Amateur Extra Class operators
D	Any licensed amateur operator

7. - E2A11

What type of antenna can be used to minimize the effects of spin modulation and Faraday rotation?

Select	Answer
A	An isotropic antenna
B	A linearly polarized antenna
C	A circularly polarized antenna
D	A log-periodic dipole array

8. - E2B17

What is the approximate bandwidth of a slow-scan TV signal?

Select	Answer
A	6 MHz
B	2 MHz
C	600 Hz
D	3 kHz

9. - E2C09

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

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

10. - E2D10

How can an APRS station be used to help support a public service communications activity?

Select	Answer
A	All of these choices are correct
B	An APRS station with an emergency medical technician can automatically transmit medical data to the nearest hospital
C	An APRS station with a GPS unit can automatically transmit information to show a mobile station's position during the event
D	APRS stations with General Personnel Scanners can automatically relay the participant numbers and time as they pass the check points

11. - E2E12

Which type of control is used by stations using the Automatic Link Enable (ALE) protocol?

Select	Answer
A	Local
B	ALE can use any type of control
C	Automatic
D	Remote

12. - E3A08

When a meteor strikes the Earth's atmosphere, a cylindrical region of free electrons is formed at what layer of the ionosphere?

Select	Answer
A	The E layer
B	The D layer
C	The F1 layer
D	The F2 layer

13. - E3B01

What is transequatorial propagation?

Select	Answer
A	Propagation between two continents by way of ducts along the magnetic equator
B	Propagation between two stations at the same latitude
C	Propagation between any two points located on the magnetic equator
D	Propagation between two mid-latitude points at approximately the same distance north and south of the magnetic equator

14. - E3C02

What is indicated by a rising A or K index?

Select	Answer
A	An increase in the critical frequency
B	Increasing disruption of the geomagnetic field
C	Decreasing disruption of the geomagnetic field
D	Higher levels of solar UV radiation

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

16. - E4B02

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

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

17. - E4C15

What is usually the primary source of noise that is heard from an HF receiver with an antenna connected?

Select	Answer
A	Detector noise
B	Atmospheric noise
C	Induction motor noise
D	Receiver front-end noise

18. - E4D11

Why are third-order intermodulation products created within a receiver of particular interest compared to other products?

Select	Answer
A	The third-order intercept is much higher than other orders
B	Third-order products are an indication of poor image rejection
C	Third-order intermodulation produces three products for every input signal within the band of interest
D	The third-order product of two signals which are in the band of interest is also likely to be within the band

19. - E4E05

How can noise from an electric motor be suppressed?

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

20. - E5A12

What is the half-power bandwidth of a parallel resonant circuit that has a resonant frequency of 3.7 MHz and a Q of 118?

Select	Answer
A	31.4 kHz
B	436.6 kHz
C	218.3 kHz
D	15.7 kHz

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

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	Maidenhead grid
D	Faraday grid

23. - E5D05

Which parasitic characteristic increases with conductor length?

Select	Answer
A	Permittivity
B	Permeability
C	Inductance
D	Malleability

24. - E6A12

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

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

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	Charge carrier depletion
D	Insufficient forward voltage

26. - E6C09

What is a Programmable Logic Device (PLD)?

Select	Answer
A	An algorithm for simulating logic functions during circuit design
B	A device to control industrial equipment
C	A programmable collection of logic gates and circuits in a single integrated circuit
D	Programmable equipment used for testing digital logic integrated circuits

27. - E6D06

What core material property determines the inductance of a toroidal inductor?

Select	Answer
A	Thermal impedance
B	Reactivity
C	Resistance
D	Permeability

28. - E6E04

Which is the most common input and output impedance of circuits that use MMICs?

Select	Answer
A	450 ohms
B	50 ohms
C	300 ohms
D	10 ohms

29. - E6F04

What is the photovoltaic effect?

Select	Answer
A	The conversion of voltage to current when exposed to light
B	The conversion of electrical energy to mechanical energy
C	The tendency of a battery to discharge when used outside
D	The conversion of light to electrical energy

30. - E7A02

What is the function of a decade counter digital IC?

Select	Answer
A	It produces one output pulse for every ten input pulses
B	It produces ten output pulses for every input pulse
C	It adds two decimal numbers together
D	It decodes a decimal number for display on a seven segment LED display

31. - E7B15

What is one way to prevent thermal runaway in a bipolar transistor amplifier?

Select	Answer
A	Use a resistor in series with the emitter
B	All of these choices are correct
C	Neutralization
D	Select transistors with high beta

32. - E7C13

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	The Q of Pi-networks can be varied depending on the component values chosen
B	L-networks cannot perform impedance transformation
C	Pi-networks are designed for balanced input and output
D	Pi-networks have fewer components

33. - E7D10

What is the primary reason that a high-frequency switching type high voltage power supply can be both less expensive and lighter in weight than a conventional power supply?

Select	Answer
A	It uses a diode bridge rectifier for increased output
B	The high frequency inverter design uses much smaller transformers and filter components for an equivalent power output
C	The inverter design does not require any output filtering
D	It uses a large power factor compensation capacitor to create free power from the unused portion of the AC cycle

34. - E7E10

How does a diode detector function?

Select	Answer
A	By rectification and filtering of RF signals
B	By mixing signals with noise in the transition region of the diode
C	By breakdown of the Zener voltage
D	By sensing the change of reactance in the diode with respect to frequency

35. - E7F09

Why is an anti-aliasing digital filter required in a digital decimator?

Select	Answer
A	It removes low frequency signal components to eliminate the need for DC restoration
B	It peaks the response of the decimator, improving bandwidth
C	It removes high-frequency signal components which would otherwise be reproduced as lower frequency components
D	It notches out the sampling frequency to avoid sampling errors

36. - E7G10

What absolute voltage gain can be expected from the circuit in Figure E7-4 when R1 is 1800 ohms and RF is 68 kilohms?

Select	Answer
A	1
B	38
C	76
D	0.03

37. - E7H08

Which of the following components can be used to reduce thermal drift in crystal oscillators?

Select	Answer
A	Wirewound resistors
B	Toroidal inductors
C	Non-inductive resistors
D	NP0 capacitors

38. - E8A13

Which of these methods is commonly used to convert analog signals to digital signals?

Select	Answer
A	Phase reversal
B	Sequential sampling
C	Level shifting
D	Harmonic regeneration

39. - E8B11

What is digital time division multiplexing?

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

40. - E8C10

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

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

41. - E8D04

What is the primary effect of extremely short rise or fall time on a CW signal?

Select	Answer
A	More difficult to copy
B	Limits data speed
C	The generation of key clicks
D	The generation of RF harmonics

42. - E9A14

What is meant by the radiation resistance of an antenna?

Select	Answer
A	The combined losses of the antenna elements and feed line
B	The resistance in the atmosphere that an antenna must overcome to be able to radiate a signal
C	The specific impedance of the antenna
D	The value of a resistance that would dissipate the same amount of power as that radiated from an antenna

43. - E9B08

How can the approximate beam-width in a given plane of a directional antenna be determined?

Select	Answer
A	Note the two points where the signal strength of the antenna is 3 dB less than maximum and compute the angular difference
B	Measure the ratio of the signal strengths of the radiated power lobes from the front and rear of the antenna
C	Draw two imaginary lines through the ends of the elements and measure the angle between the lines
D	Measure the ratio of the signal strengths of the radiated power lobes from the front and side of the antenna

44. - E9C11

How is the far-field elevation pattern of a vertically polarized antenna affected by being mounted over seawater versus rocky ground?

Select	Answer
A	The low-angle radiation increases
B	The low-angle radiation decreases
C	Both the high-angle and low-angle radiation decrease
D	The high-angle radiation increases

45. - E9D04

Why should an HF mobile antenna loading coil have a high ratio of reactance to resistance?

Select	Answer
A	To swamp out harmonics
B	To maximize losses
C	To minimize losses
D	To minimize the Q

46. - E9E05

How must the driven element in a 3-element Yagi be tuned to use a hairpin matching system?

Select	Answer
A	The driven element resonance must be lower than the operating frequency
B	The driven element reactance must be inductive
C	The driven element reactance must be capacitive
D	The driven element radiation resistance must be higher than the characteristic impedance of the transmission line

47. - E9F11

What impedance does a 1/8 wavelength transmission line present to a generator when the line is open at the far end?

Select	Answer
A	An inductive reactance
B	The same as the characteristic impedance of the line
C	A capacitive reactance
D	The same as the input impedance of the final generator stage

48. - E9G09

What third family of circles is often added to a Smith chart during the process of solving problems?

Select	Answer
A	Antenna-length circles
B	Standing wave ratio circles
C	Radiation-pattern circles
D	Coaxial-length circles

49. - E9H04

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

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

50. - E0A07

How may dangerous levels of carbon monoxide from an emergency generator be detected?

Select	Answer
A	By the odor
B	By the yellowish appearance of the gas
C	Any ordinary smoke detector can be used
D	Only with a carbon monoxide detector

Figure E7-4