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

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1. - E1A05

What is the maximum power output permitted on the 60 meter band?

Select	Answer
A	100 watts PEP effective radiated power relative to an isotropic radiator
B	100 watts PEP effective radiated power relative to the gain of a half-wave dipole
C	50 watts PEP effective radiated power relative to a dipole
D	50 watts PEP effective radiated power relative to an isotropic radiator

2. - E1B03

Within what distance must an amateur station protect an FCC monitoring facility from harmful interference?

Select	Answer
A	3 miles
B	10 miles
C	30 miles
D	1 mile

3. - E1C08

What is the maximum permissible duration of a remotely controlled station's transmissions if its control link malfunctions?

Select	Answer
A	5 minutes
B	3 minutes
C	10 minutes
D	30 seconds

4. - E1D06

Which of the following is a requirement of a space station?

Select	Answer
A	All of these choices are correct
B	The space station must be capable of changing its orbit whenever such a change is ordered by NASA
C	The space station must cease all transmissions after 5 years
D	The space station must be capable of terminating transmissions by telecommand when directed by the FCC

5. - E1E01

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

Select	Answer
A	5
B	4
C	2
D	3

6. - E1F07

When may an amateur station send a message to a business?

Select	Answer
A	When transmitting international third-party communications
B	When the total money involved does not exceed $25
C	When neither the amateur nor his or her employer has a pecuniary interest in the communications
D	When the control operator is employed by the FCC or another government agency

7. - E2A14

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

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

8. - E2B06

What is vestigial sideband modulation?

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

9. - E2C04

What type of transmission is most often used for a ham radio mesh network?

Select	Answer
A	Frequency division multiplex in the 24 GHz band
B	Spread spectrum in the 2.4 GHz band
C	Multiple Frequency Shift Keying in the 10 GHz band
D	Store and forward on the 440 MHz band

10. - E2D04

What is the purpose of digital store-and-forward functions on an Amateur Radio satellite?

Select	Answer
A	To relay messages between satellites
B	To upload operational software for the transponder
C	To store digital messages in the satellite for later download by other stations
D	To delay download of telemetry between satellites

11. - E2E04

What is indicated when one of the ellipses in an FSK crossed-ellipse display suddenly disappears?

Select	Answer
A	Selective fading has occurred
B	The mark and space signal have been inverted
C	The receiver has drifted 5 kHz from the desired receive frequency
D	One of the signal filters is saturated

12. - E3A10

Which type of atmospheric structure can create a path for microwave propagation?

Select	Answer
A	Wind shear
B	The jet stream
C	Dust devil
D	Temperature inversion

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 mid-latitude points at approximately the same distance north and south of the magnetic equator
C	Propagation between any two points located on the magnetic equator
D	Propagation between two stations at the same latitude

14. - E3C01

What does the term ray tracing describe in regard to radio communications?

Select	Answer
A	Evaluating high voltage sources for X-Rays
B	The process in which an electronic display presents a pattern
C	Modeling a radio wave's path through the ionosphere
D	Determining the radiation pattern from an array of antennas

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

16. - E4B08

Which of the following is a characteristic of a good DC voltmeter?

Select	Answer
A	High impedance input
B	Low impedance input
C	High reluctance input
D	Low reluctance input

17. - E4C13

How does a narrow-band roofing filter affect receiver performance?

Select	Answer
A	All of these choices are correct
B	It improves intelligibility by using low Q circuitry to reduce ringing
C	It improves dynamic range by attenuating strong signals near the receive frequency
D	It improves sensitivity by reducing front end noise

18. - E4D08

What causes intermodulation in an electronic circuit?

Select	Answer
A	Lack of neutralization
B	Nonlinear circuits or devices
C	Positive feedback
D	Too little gain

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	Nearby signals may appear to be excessively wide even if they meet emission standards
C	Received audio in the speech range might have an echo effect
D	FM signals can no longer be demodulated

20. - E5A13

What is an effect of increasing Q in a resonant circuit?

Select	Answer
A	Internal voltages and circulating currents increase
B	Fewer components are needed for the same performance
C	Phase shift can become uncontrolled
D	Parasitic effects are minimized

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

22. - E5C02

How are impedances described in polar coordinates?

Select	Answer
A	By phase angle and amplitude
B	By Y and G values
C	By real and imaginary parts
D	By X and R values

23. - E5D04

Why are short connections necessary at microwave frequencies?

Select	Answer
A	To increase neutralizing resistance
B	Because of ground reflections
C	To reduce phase shift along the connection
D	To reduce noise figure

24. - E6A03

Why does a PN-junction diode not conduct current when reverse biased?

Select	Answer
A	Holes in P-type material and electrons in the N-type material are separated by the applied voltage, widening the depletion region
B	Only N-type semiconductor material can conduct current
C	Only P-type semiconductor material can conduct current
D	Excess holes in P-type material combine with the electrons in N-type material, converting the entire diode into an insulator

25. - E6B05

What characteristic of a PIN diode makes it useful as an RF switch or attenuator?

Select	Answer
A	A large region of intrinsic material
B	Reverse bias controls its forward voltage drop
C	Extremely high reverse breakdown voltage
D	Ability to dissipate large amounts of power

26. - E6C12

What is BiCMOS logic?

Select	Answer
A	An integrated circuit logic family using both bipolar and CMOS transistors
B	A logic device with two CMOS circuits per package
C	A FET logic family based on bimetallic semiconductors
D	A logic family based on bismuth CMOS devices

27. - E6D05

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

Select	Answer
A	Ferrite toroids generally have better temperature stability
B	Ferrite toroids generally have lower initial permeability
C	Ferrite toroids generally require fewer turns to produce a given inductance value
D	Ferrite toroids are easier to use with surface mount technology

28. - E6E03

Which of the following materials is likely to provide the highest frequency of operation when used in MMICs?

Select	Answer
A	Silicon nitride
B	Gallium nitride
C	Silicon dioxide
D	Silicon

29. - E6F01

What is photoconductivity?

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

30. - E7A09

What logical operation is performed by an exclusive NOR gate?

Select	Answer
A	It produces logic "0" at its output only if all inputs are logic "0"
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 "1" at its output only if all inputs are logic "1"

31. - E7B04

Where on the load line of a Class A common emitter amplifier would bias normally be set?

Select	Answer
A	Where the load line intersects the voltage axis
B	At a point where the load line intersects the zero bias current curve
C	Approximately half-way between saturation and cutoff
D	At a point where the bias resistor equals the load resistor

32. - E7C12

Which describes a Pi-L-network used for matching a vacuum tube final amplifier to a 50 ohm unbalanced output?

Select	Answer
A	A matching network in which all components are isolated from ground
B	A Pi-network with an additional series inductor on the output
C	A Phase Inverter Load network
D	A network with only three discrete parts

33. - E7D16

When several electrolytic filter capacitors are connected in series to increase the operating voltage of a power supply filter circuit, why should resistors be connected across each capacitor?

Select	Answer
A	To equalize, as much as possible, the voltage drop across each capacitor
B	To provide a safety bleeder to discharge the capacitors when the supply is off
C	All of these choices are correct
D	To provide a minimum load current to reduce voltage excursions at light loads

34. - E7E10

How does a diode detector function?

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

35. - E7F11

What sets the minimum detectable signal level for an SDR in the absence of atmospheric or thermal noise?

Select	Answer
A	Reference voltage level and sample width in bits
B	Sample clock phase noise
C	Missing codes and jitter
D	Data storage transfer rate

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. - E7H11

What are the major spectral impurity components of direct digital synthesizers?

Select	Answer
A	Broadband noise
B	Digital conversion noise
C	Spurious signals at discrete frequencies
D	Nyquist limit noise

38. - E8A11

What type of information can be conveyed using digital waveforms?

Select	Answer
A	Video signals
B	Data
C	Human speech
D	All of these choices are correct

39. - E8B11

What is digital time division multiplexing?

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

40. - E8C08

How does ARQ accomplish error correction?

Select	Answer
A	If errors are detected, a retransmission is requested
B	Special polynomial codes provide automatic correction
C	Special binary codes provide automatic correction
D	If errors are detected, redundant data is substituted

41. - E8D02

What spread spectrum communications technique uses a high speed binary bit stream to shift the phase of an RF carrier?

Select	Answer
A	Frequency hopping
B	Binary phase-shift keying
C	Phase compandored spread spectrum
D	Direct sequence

42. - E9A12

How much gain does an antenna have compared to a 1/2-wavelength dipole when it has 6 dB gain over an isotropic antenna?

Select	Answer
A	3.85 dB
B	2.79 dB
C	6.0 dB
D	8.15 dB

43. - E9B16

How many elevation lobes appear in the forward direction of the antenna radiation pattern shown in Figure E9-2?

Select	Answer
A	1
B	4
C	3
D	7

44. - E9C03

What is the radiation pattern of two 1/4 wavelength vertical antennas spaced a 1/2 wavelength apart and fed in phase?

Select	Answer
A	A Figure-8 broadside to the axis of the array
B	Cardioid
C	A Figure-8 end-fire along the axis of the array
D	Omni-directional

45. - E9D02

How can linearly polarized Yagi antennas be used to produce circular polarization?

Select	Answer
A	Stack two Yagis fed 90 degrees out of phase to form an array with the respective elements in parallel planes
B	Arrange two Yagis perpendicular to each other with the driven elements at the same point on the boom fed 90 degrees out of phase
C	Arrange two Yagis collinear to each other with the driven elements fed 180 degrees out of phase
D	Stack two Yagis fed in phase to form an array with the respective elements in parallel planes

46. - E9E01

What system matches a higher impedance transmission line to a lower impedance antenna by connecting the line to the driven element in two places spaced a fraction of a wavelength each side of element center?

Select	Answer
A	The gamma matching system
B	The omega matching system
C	The delta matching system
D	The stub matching system

47. - E9F15

What impedance does a 1/2 wavelength transmission line present to a generator when the line is open at the far end?

Select	Answer
A	The same as the output impedance of the generator
B	The same as the characteristic impedance of the line
C	Very low impedance
D	Very high impedance

48. - E9G01

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

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

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. - E0A04

When evaluating a site with multiple transmitters operating at the same time, the operators and licensees of which transmitters are responsible for mitigating over-exposure situations?

Select	Answer
A	Each transmitter operating with a duty-cycle greater than 50 percent
B	Each transmitter that produces 5 percent or more of its MPE limit at accessible locations
C	Only commercial transmitters
D	Only the most powerful transmitter

Figure E9-2