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

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1. - E0A07

How may dangerous levels of carbon monoxide from an emergency generator be detected?

Select	Answer
A	Any ordinary smoke detector can be used
B	By the yellowish appearance of the gas
C	By the odor
D	Only with a carbon monoxide detector

2. - E1A07

What is the maximum power permitted on the 2200 meter band?

Select	Answer
A	1 watt EIRP (Equivalent isotropic radiated power)
B	50 watts PEP
C	100 watts PEP
D	5 watts EIRP (Equivalent isotropic radiated power)

3. - E1B06

Which of the following additional rules apply if you are installing an amateur station antenna at a site at or near a public use airport?

Select	Answer
A	You must file an Environmental Impact Statement with the EPA before construction begins
B	You must obtain a construction permit from the airport zoning authority
C	You may have to notify the Federal Aviation Administration and register it with the FCC as required by Part 17 of the FCC rules
D	You must submit engineering drawings to the FAA

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

5. - E1D02

Which of the following may transmit special codes intended to obscure the meaning of messages?

Select	Answer
A	Telecommand signals from a space telecommand station
B	Data containing personal information
C	Auxiliary relay links carrying repeater audio
D	Binary control characters

6. - E1E02

Who does Part 97 task with maintaining the pools of questions for all U.S. amateur license examinations?

Select	Answer
A	The VECs
B	The VEs
C	The FCC
D	The ARRL

7. - E1F06

Under what circumstances might the FCC issue a Special Temporary Authority (STA) to an amateur station?

Select	Answer
A	To provide temporary operation while awaiting normal licensing
B	To provide for experimental amateur communications
C	To allow regular operation on Land Mobile channels
D	To provide additional spectrum for personal use

8. - E2A04

What is meant by the term mode? as applied to an amateur radio satellite?

Select	Answer
A	Whether the satellite is in a low earth or geostationary orbit
B	The satellite's orientation with respect to the Earth
C	Whether the satellite is in a polar or equatorial orbit
D	The satellite's uplink and downlink frequency bands

9. - E2B06

What is vestigial sideband modulation?

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

10. - E2C02

Which of the following best describes the term self-spotting? in connection with HF contest operating?

Select	Answer
A	The acceptable practice of manually posting the call signs of stations on a spotting network
B	A manual technique for rapidly zero beating or tuning to a station's frequency before calling that station
C	An automatic method for rapidly zero beating or tuning to a station's frequency before calling that station
D	The often-prohibited practice of posting one's own call sign and frequency on a spotting network

11. - E2D04

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

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

12. - E2E10

Which of these digital modes has the narrowest bandwidth?

Select	Answer
A	MFSK16
B	170 Hz shift, 45-baud RTTY
C	PSK31
D	300-baud packet

13. - E3A14

What is meant by circularly polarized electromagnetic waves?

Select	Answer
A	Waves that circle the Earth
B	Waves produced by a loop antenna
C	Waves with an electric field bent into a circular shape
D	Waves with a rotating electric field

14. - E3B10

Why is chordal hop propagation desirable?

Select	Answer
A	Signals travel faster along ionospheric chords
B	Atmospheric noise is lower in the direction of chordal hop propagation
C	The signal experiences less loss compared to multi-hop using Earth as a reflector
D	The MUF for chordal hop propagation is much lower than for normal skip propagation

15. - E3C05

What orientation of Bz (B sub z) increases the likelihood that incoming particles from the sun will cause disturbed conditions?

Select	Answer
A	Northward
B	Southward
C	Westward
D	Eastward

16. - E4A06

What is the effect of aliasing on a digital oscilloscope caused by setting the time base too slow?

Select	Answer
A	A false, jittery low-frequency version of the signal is displayed
B	All signals will have a DC offset
C	Excessive blanking occurs, which prevents display of the signal
D	Calibration of the vertical scale is no longer valid

17. - E4B08

Which of the following can be used to measure the Q of a series-tuned circuit?

Select	Answer
A	The resonant frequency of the circuit
B	The inductance to capacitance ratio
C	The frequency shift
D	The bandwidth of the circuit's frequency response

18. - E4C01

What is an effect of excessive phase noise in a receiver's local oscillator?

Select	Answer
A	It can combine with strong signals on nearby frequencies to generate interference
B	It decreases receiver third-order intercept point
C	It can affect the receiver's frequency calibration
D	It limits the receiver's ability to receive strong signals

19. - E4D10

What does a third-order intercept level of 40 dBm mean with respect to receiver performance?

Select	Answer
A	A pair of 40 dBm input signals will theoretically generate a third-order intermodulation product that has the same output amplitude as either of the input signals
B	A pair of 1 mW input signals will produce a third-order intermodulation product that is 40 dB stronger than the input signal
C	Signals less than 40 dBm will not generate audible third-order intermodulation products
D	The receiver can tolerate signals up to 40 dB above the noise floor without producing third-order intermodulation products

20. - E4E02

Which of the following types of noise can often be reduced with a digital signal processing noise filter?

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

21. - E5A12

What is the half-power bandwidth of a resonant circuit that has a resonant frequency of 3.7 MHz and a Q of 118?

Select	Answer
A	31.4 kHz
B	436.6 kHz
C	218.3 kHz
D	15.7 kHz

22. - E5B11

What is the phase angle between the voltage across and the current through a series RLC circuit if XC is 25 ohms, R is 100 ohms, and XL is 50 ohms?

Select	Answer
A	14 degrees with the voltage leading the current
B	76 degrees with the voltage leading the current
C	76 degrees with the voltage lagging the current
D	14 degrees with the voltage lagging the current

23. - E5C02

How are impedances described in polar coordinates?

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

24. - E5D07

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

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

25. - E6A05

How does DC input impedance at the gate of a field-effect transistor compare with the DC input impedance of a bipolar transistor?

Select	Answer
A	They are both high impedance
B	They are both low impedance
C	An FET has lower input impedance
D	An FET has higher input impedance

26. - E6B05

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

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

27. - E6C11

In Figure E6-3, what is the schematic symbol for the NOT operation (inverter)?

Select	Answer
A	4
B	5
C	6
D	2

28. - E6D05

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

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

29. - E6E05

Which of the following noise figure values is typical of a low-noise UHF preamplifier?

Select	Answer
A	44 dBm
B	-20 dBm
C	-10 dB
D	2 dB

30. - E6F03

What is the most common configuration of an optoisolator or optocoupler?

Select	Answer
A	An LED and a phototransistor
B	An amplitude modulated helium-neon laser
C	A lens and a photomultiplier
D	A frequency modulated helium-neon laser

31. - 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	T flip-flop
D	Astable multivibrator

32. - E7B02

What is a Class D amplifier?

Select	Answer
A	A low power amplifier that uses a differential amplifier for improved linearity
B	A frequency doubling amplifier
C	A type of amplifier that uses switching technology to achieve high efficiency
D	An amplifier that uses drift-mode FETs for high efficiency

33. - E7C10

Which of the following filters would be the best choice for use in a 2 meter band repeater duplexer?

Select	Answer
A	A cavity filter
B	A DSP filter
C	An L-C filter
D	A crystal filter

34. - E7D02

What is a characteristic of a switching electronic voltage regulator?

Select	Answer
A	The resistance of a control element is varied in direct proportion to the line voltage or load current
B	It is generally less efficient than a linear regulator
C	The controlled device's duty cycle is changed to produce a constant average output voltage
D	It gives a ramp voltage at its output

35. - E7E04

What is one way a single-sideband phone signal can be generated?

Select	Answer
A	By using a reactance modulator followed by a mixer
B	By using a balanced modulator followed by a filter
C	By using a loop modulator followed by a mixer
D	By driving a product detector with a DSB signal

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	All these choices are correct
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	FIR filters can respond faster to impulses

37. - E7G03

What is the typical input impedance of an op-amp?

Select	Answer
A	100 ohms
B	Very low
C	1000 ohms
D	Very high

38. - E7H04

How is positive feedback supplied in a Colpitts oscillator?

Select	Answer
A	Through a neutralizing capacitor
B	Through a tapped coil
C	Through a capacitive divider
D	Through link coupling

39. - E8A10

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

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

40. - E8B08

What describes Orthogonal Frequency Division Multiplexing?

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

41. - E8C10

How may data rate be increased without increasing bandwidth?

Select	Answer
A	Using a more efficient digital code
B	Increasing analog-to-digital conversion resolution
C	It is impossible
D	Using forward error correction

42. - E8D08

What parameter evaluates distortion of an AFSK signal caused by excessive input audio levels?

Select	Answer
A	Intermodulation Distortion (IMD)
B	Baud rate
C	Repeat Request Rate (RRR)
D	Signal-to-noise ratio

43. - E9A06

What is the effective radiated power relative to a dipole of a repeater station with 200 watts transmitter power output, 4 dB feed line loss, 3.2 dB duplexer loss, 0.8 dB circulator loss, and 10 dBd antenna gain?

Select	Answer
A	300 watts
B	2000 watts
C	126 watts
D	317 watts

44. - E9B08

What is the far field of an antenna?

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

45. - E9C04

What happens to the radiation pattern of an unterminated long wire antenna as the wire length is increased?

Select	Answer
A	The lobes become more perpendicular to the wire
B	The front-to-back ratio decreases
C	The vertical angle increases
D	The lobes align more in the direction of the wire

46. - E9D08

What happens as the Q of an antenna increases?

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

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 provide a rejection notch that prevents the radiation of harmonics
C	To cancel the inductive reactance of the matching network
D	To transform the antenna impedance to a higher value

48. - E9F02

Which of the following has the biggest effect on the velocity factor of a transmission line?

Select	Answer
A	The center conductor resistivity
B	The termination impedance
C	Dielectric materials used in the line
D	The line length

49. - E9G04

What are the two families of circles and arcs that make up a Smith chart?

Select	Answer
A	Resistance and reactance
B	Reactance and voltage
C	Voltage and impedance
D	Resistance and voltage

50. - E9H05

What is the main drawback of a small wire-loop antenna for direction finding?

Select	Answer
A	It has a bidirectional pattern
B	It is practical for use only on VHF and higher bands
C	It has no clearly defined null
D	All these choices are correct

Figure E6-3