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

2. - E1B03

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

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

3. - E1C09

Which of these ranges of frequencies is available for an automatically controlled repeater operating below 30 MHz?

Select	Answer
A	10.100 MHz - 10.150 MHz
B	24.940 MHz - 24.990 MHz
C	29.500 MHz - 29.700 MHz
D	18.110 MHz - 18.168 MHz

4. - E1D01

What is the definition of the term telemetry?

Select	Answer
A	One-way transmission that initiates, modifies, or terminates the functions of a device at a distance
B	Two-way single channel transmissions of data
C	One-way transmission of measurements at a distance from the measuring instrument
D	Two-way radiotelephone transmissions in excess of 1000 feet

5. - E1E06

Who is responsible for the proper conduct and necessary supervision during an amateur operator license examination session?

Select	Answer
A	Each administering VE
B	The VE session manager
C	The FCC
D	The VEC coordinating the session

6. - E1F08

Which of the following types of amateur station communications are prohibited?

Select	Answer
A	Communications that have a religious content
B	Communications transmitted for hire or material compensation, except as otherwise provided in the rules
C	Communications that have a political content, except as allowed by the Fairness Doctrine
D	Communications in a language other than English

7. - E2A07

Which of the following types of signals can be relayed through a linear transponder?

Select	Answer
A	FM and CW
B	All of these choices are correct
C	PSK and Packet
D	SSB and SSTV

8. - E2B17

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

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

9. - E2C01

Which of the following is true about contest operating?

Select	Answer
A	It is mandatory to transmit the call sign of the station being worked as part of every transmission to that station
B	Every contest requires a signal report in the exchange
C	Interference to other amateurs is unavoidable and therefore acceptable
D	Operators are permitted to make contacts even if they do not submit a log

10. - E2D10

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

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

11. - E2E11

What is the difference between direct FSK and audio FSK?

Select	Answer
A	Audio FSK can be performed anywhere in the transmit chain
B	Direct FSK uses a DC-coupled data connection
C	Audio FSK has a superior frequency response
D	Direct FSK applies the data signal to the transmitter VFO

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

13. - E3B05

Which amateur bands typically support long-path propagation?

Select	Answer
A	160 meters to 40 meters
B	6 meters to 2 meters
C	30 meters to 10 meters
D	160 meters to 10 meters

14. - E3C10

What does the 304A solar parameter measure?

Select	Answer
A	The solar emission at 304 GHz, correlated to X-Ray flare levels
B	The solar wind velocity at 304 degrees from the solar equator, correlated to solar activity
C	The ratio of X-Ray flux to radio flux, correlated to sunspot number
D	UV emissions at 304 angstroms, correlated to solar flux index

15. - E4A03

Which of the following test instrument is used to display spurious signals and/or intermodulation distortion products in an SSB transmitter?

Select	Answer
A	A spectrum analyzer
B	A time-domain reflectometer
C	A logic analyzer
D	A wattmeter

16. - E4B01

Which of the following factors most affects the accuracy of a frequency counter?

Select	Answer
A	Time base accuracy
B	Decade divider accuracy
C	Temperature coefficient of the logic
D	Input attenuator accuracy

17. - E4C09

Which of the following choices is a good reason for selecting a high frequency for the design of the IF in a conventional HF or VHF communications receiver?

Select	Answer
A	Easier for front-end circuitry to eliminate image responses
B	Fewer components in the receiver
C	Improved receiver noise figure
D	Reduced drift

18. - E4D04

Which of the following may reduce or eliminate intermodulation interference in a repeater caused by another transmitter operating in close proximity?

Select	Answer
A	A band-pass filter in the feed line between the transmitter and receiver
B	A Class D final amplifier
C	A Class C final amplifier
D	A properly terminated circulator at the output of the transmitter

19. - E4E05

How can noise from an electric motor be suppressed?

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

20. - E5A09

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

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

21. - E5B03

What happens to the phase angle of a reactance when it is converted to a susceptance?

Select	Answer
A	It is shifted by 90 degrees
B	The susceptance phase angle is the inverse of the reactance phase angle
C	It is unchanged
D	The sign is reversed

22. - E5C07

What is a vector?

Select	Answer
A	A quantity with both magnitude and an angular component
B	The inverse of the tangent function
C	The inverse of the sine function
D	The value of a quantity that changes over time

23. - E5D18

How many watts are consumed in a circuit having a power factor of 0.71 if the apparent power is 500VA?

Select	Answer
A	704 W
B	252 W
C	1.42 mW
D	355 W

24. - E6A17

What are the names of the three terminals of a field-effect transistor?

Select	Answer
A	Gate 1, gate 2, drain
B	Gate, drain, source
C	Emitter, base, collector
D	Emitter, base 1, base 2

25. - E6B06

Which of the following is a common use of a hot-carrier diode?

Select	Answer
A	As a constant voltage reference in a power supply
B	As balanced mixers in FM generation
C	As a variable capacitance in an automatic frequency control circuit
D	As a VHF/UHF mixer or detector

26. - E6C04

What is the primary advantage of tri-state logic?

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

27. - E6D01

How many turns will be required to produce a 5-microhenry inductor using a powdered-iron toroidal core that has an inductance index (A L) value of 40 microhenrys/100 turns?

Select	Answer
A	79 turns
B	35 turns
C	13 turns
D	141 turns

28. - E6E12

Why are high-power RF amplifier ICs and transistors sometimes mounted in ceramic packages?

Select	Answer
A	To provide a low-pass frequency response
B	Better dissipation of heat
C	Enhanced sensitivity to light
D	High-voltage insulating ability

29. - E6F08

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

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

31. - E7B13

In Figure E7-2, what is the purpose of R?

Select	Answer
A	Collector load
B	Emitter load
C	Voltage regulation
D	Fixed bias

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

33. - E7D03

What device is typically used as a stable reference voltage in a linear voltage regulator?

Select	Answer
A	A Zener diode
B	An SCR
C	A tunnel diode
D	A varactor diode

34. - E7E03

How does an analog phase modulator function?

Select	Answer
A	By varying the tuning of a microphone preamplifier to produce PM signals
B	By varying the tuning of an amplifier tank circuit to produce PM signals
C	By varying the tuning of a microphone preamplifier to produce AM signals
D	By varying the tuning of an amplifier tank circuit to produce AM signals

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

36. - E7G04

What is meant by the term op-amp input offset voltage?

Select	Answer
A	The output voltage of the op-amp minus its input voltage
B	The potential between the amplifier input terminals of the op-amp in an open loop condition
C	The differential input voltage needed to bring the open loop output voltage to zero
D	The difference between the output voltage of the op-amp and the input voltage required in the immediately following stage

37. - E7H10

What information is contained in the lookup table of a direct digital frequency synthesizer?

Select	Answer
A	The amplitude values that represent a sine-wave output
B	The phase relationship between a reference oscillator and the output waveform
C	The synthesizer frequency limits and frequency values stored in the radio memories
D	The phase relationship between a voltage-controlled oscillator and the output waveform

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	All of these choices are correct
C	Lower the input bandwidth to increase the effective resolution
D	Remove harmonics from the output caused by the discrete analog levels generated

39. - E8B06

What is the deviation ratio of an FM-phone signal having a maximum frequency swing of plus or minus 7.5 kHz when the maximum modulation frequency is 3.5 kHz?

Select	Answer
A	47
B	0.47
C	0.214
D	2.14

40. - E8C08

How does ARQ accomplish error correction?

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

41. - E8D05

What is the most common method of reducing key clicks?

Select	Answer
A	High-pass filters at the transmitter output
B	Increase keying waveform rise and fall times
C	Low-pass filters at the transmitter output
D	Reduce keying waveform rise and fall times

42. - E9A05

What is included in the total resistance of an antenna system?

Select	Answer
A	Transmission-line resistance plus radiation resistance
B	Radiation resistance plus transmission resistance
C	Radiation resistance plus space impedance
D	Radiation resistance plus ohmic resistance

43. - E9B02

In the antenna radiation pattern shown in Figure E9-1, what is the front-to-back ratio?

Select	Answer
A	18 dB
B	24 dB
C	36 dB
D	14 dB

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

45. - E9D03

Where should a high Q loading coil be placed to minimize losses in a shortened vertical antenna?

Select	Answer
A	Near the center of the vertical radiator
B	At a voltage node
C	As close to the transmitter as possible
D	As low as possible on the vertical radiator

46. - E9E04

What is the purpose of the series capacitor in a gamma-type antenna matching network?

Select	Answer
A	To cancel the inductive reactance of the matching network
B	To provide a rejection notch that prevents the radiation of harmonics
C	To provide DC isolation between the feed line and the antenna
D	To transform the antenna impedance to a higher value

47. - E9F10

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

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

48. - E9G08

What is the process of normalization with regard to a Smith chart?

Select	Answer
A	Reassigning reactance values with regard to the resistance axis
B	Reassigning resistance values with regard to the reactance axis
C	Reassigning prime center with regard to the reactance axis
D	Reassigning impedance values with regard to the prime center

49. - E9H02

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

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

50. - E0A11

Which of the following injuries can result from using high-power UHF or microwave transmitters?

Select	Answer
A	Hearing loss caused by high voltage corona discharge
B	Ingestion of ozone gas from the cooling system
C	Localized heating of the body from RF exposure in excess of the MPE limits
D	Blood clotting from the intense magnetic field

Figure E7-2

Figure E9-1