US Amateur Radio - Amateur Extra (Element 4, 2020-2024) Practice Test

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1. - E0A01

What is the primary function of an external earth connection or ground rod?

Select	Answer
A	Lightning protection
B	Reduce received noise
C	Reduce RF current flow between pieces of equipment
D	Reduce RFI to telephones and home entertainment systems

2. - E1A14

Except in some parts of Alaska, what is the maximum power permitted on the 630 meter band?

Select	Answer
A	50 watts PEP
B	100 watts PEP
C	1 watt EIRP
D	5 watts EIRP

3. - E1B03

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

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

4. - E1C03

How do the control operator responsibilities of a station under automatic control differ from one under local control?

Select	Answer
A	Under local control a control operator is not required to be present at a control point
B	Under automatic control there is no control operator
C	Under local control there is no control operator
D	Under automatic control the control operator is not required to be present at the control point

5. - E1D10

Which amateur stations are eligible to be telecommand stations of space stations (subject to the privileges of the class of operator license held by the control operator of the station)?

Select	Answer
A	Any amateur station so designated by the space station licensee
B	All these choices are correct
C	Any amateur station designated by NASA
D	Any amateur station so designated by the ITU

6. - E1E01

For which types of out-of-pocket expenses do the Part 97 rules state that VEs and VECs may be reimbursed?

Select	Answer
A	Providing amateur operator license examination preparation training materials
B	Teaching an amateur operator license examination preparation course
C	No expenses are authorized for reimbursement
D	Preparing, processing, administering, and coordinating an examination for an amateur radio operator license

7. - E1F09

Which of the following conditions apply when transmitting spread spectrum emissions?

Select	Answer
A	A station transmitting SS emission must not cause harmful interference to other stations employing other authorized emissions
B	All these choices are correct
C	The transmission must not be used to obscure the meaning of any communication
D	The transmitting station must be in an area regulated by the FCC or in a country that permits SS emissions

8. - E2A09

What do the terms L band and S band specify regarding satellite communications?

Select	Answer
A	The 2 meter and 70 centimeter bands
B	The 23 centimeter and 13 centimeter bands
C	Which sideband to use
D	FM and Digital Store-and-Forward systems

9. - E2B02

How many horizontal lines make up a fast-scan (NTSC) television frame?

Select	Answer
A	1080
B	30
C	60
D	525

10. - E2C04

Which of the following frequencies are sometimes used for amateur radio mesh networks?

Select	Answer
A	Cable TV channels 41 through 43
B	HF frequencies where digital communications are permitted
C	The 60 meter band channel centered on 5373 kHz
D	Frequencies shared with various unlicensed wireless data services

11. - E2D05

What is one advantage of the JT65 mode?

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

12. - E2E08

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

Select	Answer
A	RTTY
B	AMTOR
C	PACTOR
D	Hellschreiber

13. - E3A11

What is a typical range for tropospheric propagation of microwave signals?

Select	Answer
A	2500 miles
B	100 miles to 300 miles
C	10 miles to 50 miles
D	1200 miles

14. - E3B12

What is the primary characteristic of chordal hop propagation?

Select	Answer
A	Propagation across the geomagnetic equator
B	Successive ionospheric refractions without an intermediate reflection from the ground
C	Signals reflected back toward the transmitting station
D	Propagation away from the great circle bearing between stations

15. - E3C13

What type of polarization is best for ground-wave propagation?

Select	Answer
A	Elliptical
B	Horizontal
C	Circular
D	Vertical

16. - E4A04

How is the compensation of an oscilloscope probe typically adjusted?

Select	Answer
A	A square wave is displayed and the probe is adjusted until the horizontal portions of the displayed wave are as nearly flat as possible
B	A high frequency sine wave is displayed and the probe is adjusted for maximum amplitude
C	A frequency standard is displayed and the probe is adjusted until the deflection time is accurate
D	A DC voltage standard is displayed and the probe is adjusted until the displayed voltage is accurate

17. - E4B10

Which of the following methods measures intermodulation distortion in an SSB transmitter?

Select	Answer
A	Modulate the transmitter using two RF signals having non-harmonically related frequencies and observe the RF output with a spectrum analyzer
B	Modulate the transmitter using two AF signals having harmonically related frequencies and observe the RF output with a peak reading wattmeter
C	Modulate the transmitter using two RF signals having harmonically related frequencies and observe the RF output with a logic analyzer
D	Modulate the transmitter using two AF signals having non-harmonically related frequencies and observe the RF output with a spectrum analyzer

18. - E4C11

Why can an attenuator be used to reduce receiver overload on the lower frequency HF bands with little or no impact on signal-to-noise ratio?

Select	Answer
A	The attenuator has a noise filter to suppress interference
B	The attenuator has a low-pass filter to increase the strength of lower frequency signals
C	Atmospheric noise is generally greater than internally generated noise even after attenuation
D	Signals are attenuated separately from the noise

19. - 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 store often-used frequencies
C	To provide a range of AGC time constants
D	To increase rejection of signals outside the desired band

20. - E4E10

What might be the cause of a loud roaring or buzzing AC line interference that comes and goes at intervals?

Select	Answer
A	A malfunctioning illuminated advertising display
B	A defective doorbell or doorbell transformer inside a nearby residence
C	All these choices are correct
D	Arcing contacts in a thermostatically controlled device

21. - E5A05

What is the result of increasing the Q of an impedance-matching circuit?

Select	Answer
A	Matching range is increased
B	Matching bandwidth is decreased
C	Matching bandwidth is increased
D	It has no effect on impedance matching

22. - E5B10

What is the relationship between the AC current through an inductor and the voltage across an inductor?

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

23. - E5C08

What coordinate system is often used to display the phase angle of a circuit containing resistance, inductive and/or capacitive reactance?

Select	Answer
A	Elliptical coordinates
B	Maidenhead grid
C	Faraday grid
D	Polar coordinates

24. - 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	400 watts
B	2000 watts
C	80 watts
D	50 watts

25. - E6A02

Which of the following semiconductor materials contains excess free electrons?

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

26. - E6B03

What type of bias is required for an LED to emit light?

Select	Answer
A	Inductive bias
B	Forward bias
C	Zero bias
D	Reverse bias

27. - E6C09

What is a Programmable Logic Device (PLD)?

Select	Answer
A	A type of transistor whose gain can be changed by digital logic circuits
B	A programmable collection of logic gates and circuits in a single integrated circuit
C	Programmable equipment used for testing digital logic integrated circuits
D	A logic circuit that can be modified during use

28. - E6D01

Why should core saturation of an impedance matching transformer be avoided?

Select	Answer
A	Magnetic flux would increase with frequency
B	Harmonics and distortion could result
C	RF susceptance would increase
D	Temporary changes of the core permeability could result

29. - E6E02

Which of the following device packages is a through-hole type?

Select	Answer
A	Ball grid array
B	DIP
C	PLCC
D	SOT

30. - E6F04

What is the photovoltaic effect?

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

31. - E7A05

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

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

32. - E7B13

Which of the following describes an emitter follower (or common collector) amplifier?

Select	Answer
A	An amplifier with a low impedance output that follows the base input voltage
B	A two-transistor amplifier with the emitters sharing a common bias resistor
C	An OR circuit with only one emitter used for output
D	A differential amplifier with both inputs fed to the emitter of the input transistor

33. - E7C07

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

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

34. - E7D08

What type of circuit is shown in Figure E7-2?

Select	Answer
A	Linear voltage regulator
B	Monostable multivibrator
C	Switching voltage regulator
D	Grounded emitter amplifier

35. - E7E09

What occurs when an excessive amount of signal energy reaches a mixer circuit?

Select	Answer
A	Mixer blanking occurs
B	A beat frequency is generated
C	Automatic limiting occurs
D	Spurious mixer products are generated

36. - E7F12

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

37. - E7G04

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

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

38. - E7H07

How can an oscillator's microphonic responses be reduced?

Select	Answer
A	Use NP0 capacitors
B	Mechanically isolate the oscillator circuitry from its enclosure
C	Increase the bias voltage
D	Reduce noise on the oscillator's power supply

39. - E8A02

Which of the following is a type of analog-to-digital conversion?

Select	Answer
A	Successive approximation
B	Harmonic regeneration
C	Phase reversal
D	Level shifting

40. - E8B03

What is the modulation index of an FM-phone signal having a maximum frequency deviation of 3000 Hz either side of the carrier frequency when the modulating frequency is 1000 Hz?

Select	Answer
A	3
B	3000
C	1000
D	0.3

41. - E8C03

Why should phase-shifting of a PSK signal be done at the zero crossing of the RF signal?

Select	Answer
A	All these choices are correct
B	To minimize bandwidth
C	To improve carrier suppression
D	To simplify modulation

42. - E8D10

What are some of the differences between the Baudot digital code and ASCII?

Select	Answer
A	Baudot uses 4 data bits per character, ASCII uses 7 or 8; Baudot uses 1 character as a letters/figures shift code, ASCII has no letters/figures code
B	Baudot uses 5 data bits per character, ASCII uses 7 or 8; Baudot uses 2 characters as letters/figures shift codes, ASCII has no letters/figures shift code
C	Baudot uses 6 data bits per character, ASCII uses 7 or 8; Baudot has no letters/figures shift code, ASCII uses 2 letters/figures shift codes
D	Baudot uses 7 data bits per character, ASCII uses 8; Baudot has no letters/figures shift code, ASCII uses 2 letters/figures shift codes

43. - E9A07

What is the effective isotropic radiated power of a repeater station with 200 watts transmitter power output, 2 dB feed line loss, 2.8 dB duplexer loss, 1.2 dB circulator loss, and 7 dBi antenna gain?

Select	Answer
A	63.2 watts
B	632 watts
C	159 watts
D	252 watts

44. - E9B10

What is the principle of a Method of Moments analysis?

Select	Answer
A	A wire is modeled as a single sine-wave voltage source
B	A wire is modeled as a series of segments, each having a distinct value of voltage across it
C	A wire is modeled as a single sine-wave current generator
D	A wire is modeled as a series of segments, each having a uniform value of current

45. - E9C13

How does the radiation pattern of a horizontally polarized 3-element beam antenna vary with increasing height above ground?

Select	Answer
A	The horizontal beamwidth increases
B	The horizontal beamwidth decreases
C	The takeoff angle of the lowest elevation lobe increases
D	The takeoff angle of the lowest elevation lobe decreases

46. - E9D01

How much does the gain of an ideal parabolic dish antenna change when the operating frequency is doubled?

Select	Answer
A	2 dB
B	4 dB
C	6 dB
D	3 dB

47. - E9E04

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

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

48. - 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	A capacitive reactance
B	An inductive reactance
C	The same as the characteristic impedance of the line
D	Zero

49. - E9G05

Which of the following is a common use for a Smith chart?

Select	Answer
A	Determine the impedance of a transmission line, given the physical dimensions
B	Determine the length and position of an impedance matching stub
C	Determine the loss/100 feet of a transmission line, given the velocity factor and conductor materials
D	Determine the gain of an antenna given the physical and electrical parameters

50. - E9H06

What is the triangulation method of direction finding?

Select	Answer
A	A fixed receiving station uses three different antennas to plot the location of the signal source
B	The geometric angles of sky waves from the source are used to determine its position
C	Antenna headings from several different receiving locations are used to locate the signal source
D	A fixed receiving station plots three headings to the signal source

Figure E7-2