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

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1. - E0A02

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

Select	Answer
A	Ensure signals from your station are less than the controlled Maximum Permitted Exposure (MPE) limits
B	Ensure signals from your station are less than the controlled Maximum Permitted Emission (MPE) limits
C	Ensure signals from your station are less than the uncontrolled Maximum Permitted Emission (MPE) limits
D	Ensure signals from your station are less than the uncontrolled Maximum Permitted Exposure (MPE) limits

2. - E1A08

If a station in a message forwarding system inadvertently forwards a message that is in violation of FCC rules, who is primarily accountable for the rules violation?

Select	Answer
A	The control operators of all the stations in the system
B	The control operator of the packet bulletin board station
C	The control operators of all the stations in the system not authenticating the source from which they accept communications
D	The control operator of the originating station

3. - E1B11

What does PRB-1 require of regulations affecting amateur radio?

Select	Answer
A	Reasonable accommodations of amateur radio must be made
B	Amateur radio operations must be permitted in any private residence
C	No limitations may be placed on antenna size or placement
D	Use of wireless devices in a vehicle is exempt from regulation

4. - E1C13

What notifications must be given before transmitting on the 630 meter or 2200 meter bands?

Select	Answer
A	Operators must inform the Utilities Technology Council (UTC) of their call sign and coordinates of the station
B	A special endorsement must be requested from the FCC
C	An environmental impact statement must be filed with the Department of the Interior
D	Operators must inform the FAA of their intent to operate, giving their call sign and distance to the nearest runway

5. - E1D01

What is the definition of telemetry?

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

6. - E1E05

What is the minimum passing score on all amateur operator license examinations?

Select	Answer
A	Minimum passing score of 70%
B	Minimum passing score of 74%
C	Minimum passing score of 77%
D	Minimum passing score of 80%

7. - E1F07

When may an amateur station send a message to a business?

Select	Answer
A	When the total money involved does not exceed $25
B	When the control operator is employed by the FCC or another government agency
C	When neither the amateur nor his or her employer has a pecuniary interest in the communications
D	When transmitting international third-party communications

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	Whether the satellite is in a polar or equatorial orbit
C	The satellite's orientation with respect to the Earth
D	The satellite's uplink and downlink frequency bands

9. - E2B10

What aspect of an analog slow-scan television signal encodes the brightness of the picture?

Select	Answer
A	Tone amplitude
B	Sync amplitude
C	Tone frequency
D	Sync frequency

10. - 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	Repeater contacts between U.S. club members
C	Special event contacts between stations in the U.S.
D	Contacts between a U.S. station and a non-U.S. station

11. - E2D04

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

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

12. - E2E08

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

Select	Answer
A	Hellschreiber
B	PACTOR
C	RTTY
D	AMTOR

13. - E3A04

What do Hepburn maps predict?

Select	Answer
A	Likelihood of rain scatter along cold or warm fronts
B	Probability of tropospheric propagation
C	Locations of auroral reflecting zones
D	Sporadic E propagation

14. - E3B12

What is the primary characteristic of chordal hop propagation?

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

15. - E3C04

What does the value of Bz (B sub Z) represent?

Select	Answer
A	Critical frequency for vertical transmissions
B	Duration of long-delayed echoes
C	Direction and strength of the interplanetary magnetic field
D	Geomagnetic field stability

16. - E4A04

How is the compensation of an oscilloscope probe typically adjusted?

Select	Answer
A	A high frequency sine wave is displayed and the probe is adjusted for maximum amplitude
B	A square wave is displayed and the probe is adjusted until the horizontal portions of the displayed wave are as nearly flat as possible
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. - E4B07

What do the subscripts of S parameters represent?

Select	Answer
A	Frequency order of the measurements
B	Relative quality of the data
C	The relative time between measurements
D	The port or ports at which measurements are made

18. - E4C01

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

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

19. - E4D09

What is the purpose of the preselector in a communications receiver?

Select	Answer
A	To store often-used frequencies
B	To allow selection of the optimum RF amplifier device
C	To increase rejection of signals outside the desired band
D	To provide a range of AGC time constants

20. - E4E04

How can conducted and radiated noise caused by an automobile alternator be suppressed?

Select	Answer
A	By connecting the radio's power leads directly to the battery and by installing coaxial capacitors in line with the alternator leads
B	By installing filter capacitors in series with the DC power lead and a blocking capacitor in the field lead
C	By installing a noise suppression resistor and a blocking capacitor in both leads
D	By installing a high-pass filter in series with the radio's power lead and a low-pass filter in parallel with the field lead

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	436.6 kHz
B	15.7 kHz
C	218.3 kHz
D	31.4 kHz

22. - E5B12

What is admittance?

Select	Answer
A	The turns ratio of a transformer
B	The term for the gain of a field effect transistor
C	The inverse of Q factor
D	The inverse of impedance

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	Polar coordinates
D	Faraday grid

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	80 watts
B	50 watts
C	400 watts
D	2000 watts

25. - E6A07

Which of the following indicates that a silicon NPN junction transistor is biased on?

Select	Answer
A	Base-to-emitter resistance of approximately 0.6 to 0.7 ohms
B	Base-to-emitter voltage of approximately 0.6 to 0.7 volts
C	Base-to-emitter resistance of approximately 6 to 7 ohms
D	Base-to-emitter voltage of approximately 6 to 7 volts

26. - E6B08

Which of the following is a Schottky barrier diode?

Select	Answer
A	Thermionic emission diode
B	Metal-semiconductor junction
C	PIN junction
D	Electrolytic rectifier

27. - E6C07

What best describes a pull-up or pull-down resistor?

Select	Answer
A	A resistor connected to the positive or negative supply line used to establish a voltage when an input or output is an open circuit
B	A resistor in a keying circuit used to reduce key clicks
C	A resistor connected to an op-amp output that prevents signals from exceeding the power supply voltage
D	A resistor that ensures that an oscillator frequency does not drift

28. - E6D08

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

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

29. - E6E03

Which of the following materials is likely to provide the highest frequency of operation when used in MMICs?

Select	Answer
A	Silicon nitride
B	Silicon dioxide
C	Silicon
D	Gallium nitride

30. - E6F03

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

Select	Answer
A	A frequency modulated helium-neon laser
B	A lens and a photomultiplier
C	An LED and a phototransistor
D	An amplitude 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	T flip-flop
B	Monostable multivibrator
C	Astable multivibrator
D	J-K flip-flop

32. - E7B08

How can an RF power amplifier be neutralized?

Select	Answer
A	By increasing the driving power
B	By feeding a 180-degree out-of-phase portion of the output back to the input
C	By feeding an in-phase component of the output back to the input
D	By reducing the driving power

33. - E7C03

What advantage does a series-L Pi-L-network have over a series-L Pi-network for impedance matching between the final amplifier of a vacuum-tube transmitter and an antenna?

Select	Answer
A	Greater transformation range
B	Higher efficiency
C	Greater harmonic suppression
D	Does not require a capacitor

34. - E7D11

What is the function of the pass transistor in a linear voltage regulator circuit?

Select	Answer
A	Maintains nearly constant output impedance over a wide range of load current
B	Permits a wide range of output voltage settings
C	Maintains nearly constant output voltage over a wide range of load current
D	Provides a stable input impedance over a wide range of source voltage

35. - E7E05

What circuit is added to an FM transmitter to boost the higher audio frequencies?

Select	Answer
A	A heterodyne enhancer
B	A heterodyne suppressor
C	A pre-emphasis network
D	A de-emphasis network

36. - E7F09

Why is an anti-aliasing digital filter required in a digital decimator?

Select	Answer
A	It peaks the response of the decimator, improving bandwidth
B	It notches out the sampling frequency to avoid sampling errors
C	It removes low-frequency signal components to eliminate the need for DC restoration
D	It removes high-frequency signal components that would otherwise be reproduced as lower frequency components

37. - E7G04

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

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

38. - E7H02

What is a microphonic?

Select	Answer
A	Changes in oscillator frequency due to mechanical vibration
B	An IC used for amplifying microphone signals
C	Distortion caused by RF pickup on the microphone cable
D	Excess loading of the microphone by an oscillator

39. - E8A06

What is the approximate ratio of PEP-to-average power in a typical single-sideband phone signal?

Select	Answer
A	1 to 1
B	2.5 to 1
C	25 to 1
D	100 to 1

40. - E8B01

What is the modulation index of an FM signal?

Select	Answer
A	The type of modulation used by the transmitter
B	The bandwidth of the transmitted signal divided by the modulating signal frequency
C	The ratio of modulating signal amplitude to frequency deviation
D	The ratio of frequency deviation to modulating signal frequency

41. - E8C07

What is the bandwidth of a 4800-Hz frequency shift, 9600-baud ASCII FM transmission?

Select	Answer
A	9.6 kHz
B	5.76 kHz
C	4.8 kHz
D	15.36 kHz

42. - E8D09

What is considered an acceptable maximum IMD level for an idling PSK signal?

Select	Answer
A	+15 dB
B	+10 dB
C	-20 dB
D	-30 dB

43. - E9A11

Which of the following factors determines ground losses for a ground-mounted vertical antenna operating in the 3 MHz to 30 MHz range?

Select	Answer
A	Soil conductivity
B	Take-off angle
C	The standing wave ratio
D	Distance from the transmitter

44. - E9B11

What is a disadvantage of decreasing the number of wire segments in an antenna model below 10 segments per half-wavelength?

Select	Answer
A	The resulting design will favor radiation of harmonic energy
B	The computed feed point impedance may be incorrect
C	The antenna will become mechanically unstable
D	Ground conductivity will not be accurately modeled

45. - E9C12

Which of the following describes an Extended Double Zepp antenna?

Select	Answer
A	A portable antenna erected using two push support poles
B	A center-fed 1.25-wavelength antenna (two 5/8-wave elements in phase)
C	A wideband vertical antenna constructed from precisely tapered aluminum tubing
D	An end-fed folded dipole antenna

46. - E9D03

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

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

47. - E9E06

Which of these feed line impedances would be suitable for constructing a quarter-wave Q-section for matching a 100-ohm loop to 50-ohm feed line?

Select	Answer
A	450 ohms
B	75 ohms
C	50 ohms
D	62 ohms

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

49. - E9G07

On the Smith chart shown in Figure E9-3, what is the only straight line shown?

Select	Answer
A	The voltage axis
B	The resistance axis
C	The current axis
D	The reactance axis

50. - E9H07

Why is RF attenuation used when direction-finding?

Select	Answer
A	To prevent receiver overload which reduces pattern nulls
B	To narrow the receiver bandwidth
C	To increase receiver sensitivity
D	To compensate for isotropic directivity and the antenna effect of feed lines

Figure E9-3