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

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1. - E1A06

Where must the carrier frequency of a CW signal be set to comply with FCC rules for 60 meter operation?

Select	Answer
A	At the center frequency of the channel
B	At the highest frequency of the channel
C	At the lowest frequency of the channel
D	On any frequency where the signal's sidebands are within the channel

2. - E1B08

What limitations may the FCC place on an amateur station if its signal causes interference to domestic broadcast reception, assuming that the receivers involved are of good engineering design?

Select	Answer
A	The amateur station must cease operation on all frequencies below 30 MHz
B	The amateur station must cease operation
C	The amateur station must avoid transmitting during certain hours on frequencies that cause the interference
D	The amateur station must cease operation on all frequencies above 30 MHz

3. - E1C02

What is meant by automatic control of a station?

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

4. - E1D11

Which amateur stations are eligible to operate as Earth stations?

Select	Answer
A	Any amateur station, subject to the privileges of the class of operator license held by the control operator
B	Any amateur station whose licensee has filed a pre-space notification with the FCC's International Bureau
C	Only those of Amateur Extra Class operators
D	Only those of General, Advanced or Amateur Extra Class operators

5. - E1E02

Where are the questions for all written U.S. amateur license examinations listed?

Select	Answer
A	In a question pool maintained by the FCC
B	In a question pool maintained by all the VECs
C	In the appropriate FCC Report and Order
D	In FCC Part 97

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 kW
C	1.5 W
D	10 W

7. - E2A14

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

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

8. - E2B04

What is blanking in a video signal?

Select	Answer
A	Turning off the scanning beam at the conclusion of a transmission
B	Turning off the scanning beam while it is traveling from right to left or from bottom to top
C	Transmitting a black and white test pattern
D	Synchronization of the horizontal and vertical sync pulses

9. - E2C08

Which of the following contacts may be confirmed through the U.S. QSL bureau system?

Select	Answer
A	Contacts using tactical call signs
B	Special event contacts between stations in the U.S.
C	Contacts between a U.S. station and a non-U.S. station
D	Repeater contacts between U.S. club members

10. - E2D03

Which of the following digital modes is especially useful for EME communications?

Select	Answer
A	PACTOR III
B	Olivia
C	JT65
D	FSK441

11. - E2E08

Which of the following HF digital modes can be used to transfer binary files?

Select	Answer
A	RTTY
B	PACTOR
C	AMTOR
D	Hellschreiber

12. - E3A05

Tropospheric propagation of microwave signals often occurs along what weather related structure?

Select	Answer
A	Lightning discharges
B	Sprites and jets
C	Warm and cold fronts
D	Gray-line

13. - E3B09

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

Select	Answer
A	Around the solstices, especially the summer solstice
B	Around the equinoxes, especially the spring equinox
C	Around the equinoxes, especially the fall equinox
D	Around the solstices, especially the winter solstice

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 peaks at roughly 14 MHz
D	It increases

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

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	There is an impedance mismatch between the antenna and feed line
C	The transmitter is not properly neutralized
D	There is more power going into the antenna

17. - E4C08

An SDR receiver is overloaded when input signals exceed what level?

Select	Answer
A	One-half the maximum sampling buffer size
B	The maximum count value of the analog-to-digital converter
C	The reference voltage of the analog-to-digital converter
D	One-half the maximum sample rate

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 store often-used frequencies
D	To increase rejection of unwanted signals

19. - E4E02

Which of the following types of receiver noise can often be reduced with a DSP noise filter?

Select	Answer
A	Power line noise
B	Broadband white noise
C	All of these choices are correct
D	Ignition noise

20. - E5A10

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

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

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	Current leads voltage by 90 degrees
C	Voltage and current are in phase
D	Voltage leads current by 90 degrees

22. - E5C04

Which of the following represents a capacitive reactance in polar coordinates?

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

23. - E5D12

How many watts are consumed in a circuit having a power factor of 0.2 if the input is 100-VAC at 4 amperes?

Select	Answer
A	50 watts
B	80 watts
C	400 watts
D	2000 watts

24. - E6A04

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

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

25. - E6B02

What is an important characteristic of a Schottky diode as compared to an ordinary silicon diode when used as a power supply rectifier?

Select	Answer
A	Controlled reverse avalanche voltage
B	Less forward voltage drop
C	Much higher reverse voltage breakdown
D	Enhanced carrier retention time

26. - E6C04

What is the primary advantage of tri-state logic?

Select	Answer
A	More efficient arithmetic operations
B	Ability to connect many device outputs to a common bus
C	Low power consumption
D	High speed operation

27. - E6D10

What is a primary advantage of using a toroidal core instead of a solenoidal core in an inductor?

Select	Answer
A	Toroidal cores exhibit greater hysteresis
B	Toroidal cores have lower Q characteristics
C	Toroidal cores make it easier to couple the magnetic energy into other components
D	Toroidal cores confine most of the magnetic field within the core material

28. - E6E07

Which of the following is typically used to construct a MMIC-based microwave amplifier?

Select	Answer
A	Ground-plane construction
B	Wave-soldering construction
C	Microstrip construction
D	Point-to-point construction

29. - E6F02

What happens to the conductivity of a photoconductive material when light shines on it?

Select	Answer
A	It decreases
B	It stays the same
C	It increases
D	It becomes unstable

30. - E7A08

What logical operation does an OR gate perform?

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

31. - E7B01

For what portion of a signal cycle does a Class AB amplifier operate?

Select	Answer
A	More than 180 degrees but less than 360 degrees
B	Less than 180 degrees
C	The entire cycle
D	Exactly 180 degrees

32. - E7C15

What is a crystal lattice filter?

Select	Answer
A	A filter with wide bandwidth and shallow skirts made using quartz crystals
B	A filter with narrow bandwidth and steep skirts made using quartz crystals
C	An audio filter made with four quartz crystals that resonate at 1kHz intervals
D	A power supply filter made with interlaced quartz crystals

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

34. - E7E01

Which of the following can be used to generate FM phone emissions?

Select	Answer
A	A balanced modulator on the oscillator
B	A balanced modulator on the audio amplifier
C	A reactance modulator on the final amplifier
D	A reactance modulator on the oscillator

35. - E7F15

Which of the following is an advantage of a Finite Impulse Response (FIR) filter vs an Infinite Impulse Response (IIR) digital filter?

Select	Answer
A	All of these choices are correct
B	FIR filters delay all frequency components of the signal by the same amount
C	FIR filters can respond faster to impulses
D	FIR filters are easier to implement for a given set of passband rolloff requirements

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 linearly with increasing frequency
D	It decreases logarithmically with increasing frequency

37. - E7H09

What type of frequency synthesizer circuit uses a phase accumulator, lookup table, digital to analog converter, and a low-pass anti-alias filter?

Select	Answer
A	A phase locked loop synthesizer
B	A direct digital synthesizer
C	A hybrid synthesizer
D	A diode-switching matrix synthesizer

38. - E8A10

What is the purpose of a low pass filter used in conjunction with a digital-to-analog converter?

Select	Answer
A	Improve accuracy by removing out of sequence codes from the input
B	Remove harmonics from the output caused by the discrete analog levels generated
C	Lower the input bandwidth to increase the effective resolution
D	All of these choices are correct

39. - E8B08

What describes Orthogonal Frequency Division Multiplexing?

Select	Answer
A	A frequency modulation technique which uses non-harmonically related frequencies
B	A bandwidth compression technique using Fourier transforms
C	A digital mode for narrow band, slow speed transmissions
D	A digital modulation technique using subcarriers at frequencies chosen to avoid intersymbol interference

40. - E8C03

When performing phase shift keying, why is it advantageous to shift phase precisely at the zero crossing of the RF carrier?

Select	Answer
A	It improves carrier suppression
B	This results in the least possible transmitted bandwidth for the particular mode
C	It is easier to demodulate with a conventional, non-synchronous detector
D	All of these choices are correct

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

42. - E9A18

What term describes station output, taking into account all gains and losses?

Select	Answer
A	Half-power bandwidth
B	Apparent power
C	Power factor
D	Effective radiated power

43. - E9B12

What is the far field of an antenna?

Select	Answer
A	The region where radiated power dissipates over a specified time period
B	The region of the ionosphere where radiated power is not refracted
C	The region where radiated field strengths are obstructed by objects of reflection
D	The region where the shape of the antenna pattern is independent of distance

44. - E9C05

What is an OCFD antenna?

Select	Answer
A	A multiband dipole antenna using one-way circular polarization for frequency diversity
B	An eight band dipole antenna using octophase filters
C	A dipole feed approximately 1/3 the way from one end with a 4:1 balun to provide multiband operation
D	A remotely tunable dipole antenna using orthogonally controlled frequency diversity

45. - E9D05

What is a disadvantage of using a multiband trapped antenna?

Select	Answer
A	It is too sharply directional at lower frequencies
B	It might radiate harmonics
C	It must be neutralized
D	It radiates the harmonics and fundamental equally well

46. - E9E11

What is an effective way of matching a feed line to a VHF or UHF antenna when the impedances of both the antenna and feed line are unknown?

Select	Answer
A	Use a 50 ohm 1:1 balun between the antenna and feed line
B	Use the universal stub matching technique
C	Connect a parallel-resonant LC network across the antenna feed terminals
D	Connect a series-resonant LC network across the antenna feed terminals

47. - E9F04

What is the typical velocity factor for a coaxial cable with solid polyethylene dielectric?

Select	Answer
A	0.66
B	2.70
C	0.30
D	0.10

48. - E9G01

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

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

49. - E9H07

Why is it advisable to use an RF attenuator on a receiver being used for direction finding?

Select	Answer
A	It reduces loss of received signals caused by antenna pattern nulls, thereby increasing sensitivity
B	It prevents receiver overload which could make it difficult to determine peaks or nulls
C	It narrows the bandwidth of the received signal to improve signal to noise ratio
D	It compensates for the effects of an isotropic antenna, thereby improving directivity

50. - E0A05

What is one of the potential hazards of using microwaves in the amateur radio bands?

Select	Answer
A	Microwaves are ionizing radiation
B	The high gain antennas commonly used can result in high exposure levels
C	The extremely high frequency energy can damage the joints of antenna structures
D	Microwaves often travel long distances by ionospheric reflection