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	60 Hz
B	1.5 kHz
C	2.8 kHz
D	170 Hz

2. - E1B11

What is the permitted mean power of any spurious emission relative to the mean power of the fundamental emission from a station transmitter or external RF amplifier installed after January 1, 2003 and transmitting on a frequency below 30 MHZ?

Select	Answer
A	At least 53 dB below
B	At least 63 dB below
C	At least 43 dB below
D	At least 73 dB below

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, beacon or space stations
C	Only auxiliary, repeater or space stations
D	Only beacon, repeater or space stations

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 terminating transmissions by telecommand when directed by the FCC
C	The space station must be capable of changing its orbit whenever such a change is ordered by NASA
D	The space station must cease all transmissions after 5 years

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

6. - E1F10

What is the maximum permitted transmitter peak envelope power for an amateur station transmitting spread spectrum communications?

Select	Answer
A	1 W
B	1.5 W
C	10 W
D	1.5 kW

7. - E2A05

What do the letters in a satellite's mode designator specify?

Select	Answer
A	Power limits for uplink and downlink transmissions
B	The polarization of uplink and downlink signals
C	The uplink and downlink frequency ranges
D	The location of the ground control station

8. - E2B07

What is the name of the signal component that carries color information in NTSC video?

Select	Answer
A	Luminance
B	Spectral Intensity
C	Hue
D	Chroma

9. - E2C11

How should you generally identify your station when attempting to contact a DX station during a contest or in a pileup?

Select	Answer
A	Send your full call sign and grid square
B	Send your full call sign once or twice
C	Send only the last two letters of your call sign until you make contact
D	Send the call sign of the DX station three times, the words "this is", then your call sign three times

10. - E2D14

What is one advantage of using JT65 coding?

Select	Answer
A	Uses only a 65 Hz bandwidth
B	Permits fast-scan TV transmissions over narrow bandwidth
C	The ability to decode signals which have a very low signal to noise ratio
D	Easily copied by ear if necessary

11. - E2E02

What do the letters FEC mean as they relate to digital operation?

Select	Answer
A	Fatal Error Correction
B	Final Error Correction
C	Forward Error Correction
D	First Error Correction

12. - E3A01

What is the approximate maximum separation measured along the surface of the Earth between two stations communicating by Moon bounce?

Select	Answer
A	2000 miles, if the Moon is at apogee
B	12,000 miles, if the Moon is visible by both stations
C	500 miles, if the Moon is at perigee
D	5000 miles, if the Moon is at perigee

13. - E3B11

At what time of day is Sporadic-E propagation most likely to occur?

Select	Answer
A	Around sunset
B	Any time
C	Early evening
D	Around sunrise

14. - E3C07

Which of the following descriptors indicates the greatest solar flare intensity?

Select	Answer
A	Class B
B	Class X
C	Class A
D	Class M

15. - E4A06

What is the effect of aliasing in a digital or computer-based oscilloscope?

Select	Answer
A	Calibration of the vertical scale is no longer valid
B	False triggering occurs
C	All signals will have a DC offset
D	False signals are displayed

16. - E4B17

What three test loads are used to calibrate a standard RF vector network analyzer?

Select	Answer
A	Short circuit, open circuit, and 50 ohms
B	Short circuit, open circuit, and resonant circuit
C	50 ohms, 75 ohms, and 90 ohms
D	50 ohms through 1/8 wavelength, 1/4 wavelength, and 1/2 wavelength of coaxial cable

17. - E4C14

What transmit frequency might generate an image response signal in a receiver tuned to 14.300 MHz and which uses a 455 kHz IF frequency?

Select	Answer
A	14.445 MHz
B	15.210 MHz
C	13.845 MHz
D	14.755 MHz

18. - E4D03

How can intermodulation interference between two repeaters occur?

Select	Answer
A	When the signals from the transmitters are reflected out of phase from airplanes passing overhead
B	When the repeaters are in close proximity and the signals cause feedback in the final amplifier of one or both transmitters
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. - E4E14

What is one type of electrical interference that might be caused by the operation of a nearby personal computer?

Select	Answer
A	The appearance of unstable modulated or unmodulated signals at specific frequencies
B	A loud AC hum in the audio output of your station receiver
C	A clicking noise at intervals of a few seconds
D	A whining type noise that continually pulses off and on

20. - E5A02

What is resonance in an electrical circuit?

Select	Answer
A	The highest frequency that will pass current
B	The frequency at which the capacitive reactance equals the inductive reactance
C	The lowest frequency that will pass current
D	The frequency at which the reactive impedance equals the resistive impedance

21. - E5B06

What is susceptance?

Select	Answer
A	The magnetic impedance of a circuit
B	The inverse of reactance
C	The ratio of magnetic field to electric field
D	A measure of the efficiency of a transformer

22. - E5C02

How are impedances described in polar coordinates?

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

23. - E5D17

How many watts are consumed in a circuit having a power factor of 0.6 if the input is 200VAC at 5 amperes?

Select	Answer
A	1000 watts
B	600 watts
C	200 watts
D	1600 watts

24. - E6A02

Which of the following semiconductor materials contains excess free electrons?

Select	Answer
A	P-type
B	Bipolar
C	Insulated gate
D	N-type

25. - E6B03

What special type of diode is capable of both amplification and oscillation?

Select	Answer
A	Tunnel
B	Point contact
C	Junction
D	Zener

26. - E6C10

In Figure E6-5, what is the schematic symbol for a NOR gate?

Select	Answer
A	2
B	4
C	3
D	1

27. - E6D08

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

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

28. - E6E08

How is voltage from a power supply normally furnished to the most common type of monolithic microwave integrated circuit (MMIC)?

Select	Answer
A	Through a capacitor and RF choke connected to the amplifier input lead
B	MMICs require no operating bias
C	Directly to the bias voltage (VCC IN) lead
D	Through a resistor and/or RF choke connected to the amplifier output lead

29. - E6F08

Why are optoisolators often used in conjunction with solid state circuits when switching 120VAC?

Select	Answer
A	Optoisolators provide a very high degree of electrical isolation between a control circuit and the circuit being switched
B	Optoisolators provide impedance matching between the control circuit and power circuit
C	Optoisolators provide a low impedance link between a control circuit and a power circuit
D	Optoisolators eliminate the effects of reflected light in the control circuit

30. - E7A05

Which of the following is a circuit that continuously alternates between two states without an external clock?

Select	Answer
A	Monostable multivibrator
B	J-K flip-flop
C	Astable multivibrator
D	T flip-flop

31. - E7B17

Why are odd-order rather than even-order intermodulation distortion products of concern in linear power amplifiers?

Select	Answer
A	Because they maintain the sidebands, thus causing multiple duplicate signals
B	Because they are relatively close in frequency to the desired signal
C	Because they invert the sidebands causing distortion
D	Because they are relatively far in frequency from the desired signal

32. - E7C04

How does an impedance-matching circuit transform a complex impedance to a resistive impedance?

Select	Answer
A	It introduces negative resistance to cancel the resistive part of impedance
B	It cancels the reactive part of the impedance and changes the resistive part to a desired value
C	It introduces transconductance to cancel the reactive part of impedance
D	Network resistances are substituted for load resistances and reactances are matched to the resistances

33. - E7D14

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

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

34. - E7E10

How does a diode detector function?

Select	Answer
A	By rectification and filtering of RF signals
B	By breakdown of the Zener voltage
C	By mixing signals with noise in the transition region of the diode
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 high-frequency signal components which would otherwise be reproduced as lower frequency components
B	It notches out the sampling frequency to avoid sampling errors
C	It peaks the response of the decimator, improving bandwidth
D	It removes low frequency signal components to eliminate the need for DC restoration

36. - E7G08

How does the gain of an ideal operational amplifier vary with frequency?

Select	Answer
A	It increases linearly with increasing frequency
B	It does not vary with frequency
C	It decreases logarithmically with increasing frequency
D	It decreases linearly with increasing frequency

37. - E7H15

Which of these functions can be performed by a phase-locked loop?

Select	Answer
A	Frequency synthesis, FM demodulation
B	Comparison of two digital input signals, digital pulse counter
C	Photovoltaic conversion, optical coupling
D	Wide-band AF and RF power amplification

38. - E8A01

What is the name of the process that shows that a square wave is made up of a sine wave plus all of its odd harmonics?

Select	Answer
A	Vector analysis
B	Numerical analysis
C	Fourier analysis
D	Differential analysis

39. - E8B07

Orthogonal Frequency Division Multiplexing is a technique used for which type of amateur communication?

Select	Answer
A	Extremely low-power contacts
B	EME
C	OFDM signals are not allowed on amateur bands
D	High speed digital modes

40. - E8C01

How is Forward Error Correction implemented?

Select	Answer
A	By varying the frequency shift of the transmitted signal according to a predefined algorithm
B	By the receiving station repeating each block of three data characters
C	By transmitting a special algorithm to the receiving station along with the data characters
D	By transmitting extra data that may be used to detect and correct transmission errors

41. - E8D06

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

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

42. - E9A03

Why would one need to know the feed point impedance of an antenna?

Select	Answer
A	To calculate the front-to-side ratio of the antenna
B	To calculate the front-to-back ratio of the antenna
C	To measure the near-field radiation density from a transmitting antenna
D	To match impedances in order to minimize standing wave ratio on the transmission line

43. - E9B15

What is the front-to-back ratio of the radiation pattern shown in Figure E9-2?

Select	Answer
A	24 dB
B	3 dB
C	15 dB
D	28 dB

44. - E9C14

How does the performance of a horizontally polarized antenna mounted on the side of a hill compare with the same antenna mounted on flat ground?

Select	Answer
A	The horizontal beam width increases in the uphill direction
B	The horizontal beam width decreases in the downhill direction
C	The main lobe takeoff angle increases in the downhill direction
D	The main lobe takeoff angle decreases in the downhill direction

45. - E9D08

What happens as the Q of an antenna increases?

Select	Answer
A	SWR bandwidth increases
B	Gain is reduced
C	SWR bandwidth decreases
D	More common-mode current is present on the feed line

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

47. - E9F01

What is the velocity factor of a transmission line?

Select	Answer
A	The index of shielding for coaxial cable
B	The velocity of the wave in the transmission line multiplied by the velocity of light in a vacuum
C	The velocity of the wave in the transmission line divided by the velocity of light in a vacuum
D	The ratio of the characteristic impedance of the line to the terminating impedance

48. - E9G01

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

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

49. - E9H02

Which is generally true for low band (160 meter and 80 meter) receiving antennas?

Select	Answer
A	Low loss coax transmission line is essential for good performance
B	All of these choices are correct
C	They must be erected at least 1/2 wavelength above the ground to attain good directivity
D	Atmospheric noise is so high that gain over a dipole is not important

50. - E0A02

When evaluating RF exposure levels from your station at a neighbor's home, what must you do?

Select	Answer
A	You need only evaluate exposure levels on your own property
B	Make sure signals from your station are less than the controlled MPE limits
C	Advise your neighbors of the results of your tests
D	Make sure signals from your station are less than the uncontrolled MPE limits

Figure E6-5

Figure E9-2