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

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1. - E0A04

When evaluating a site with multiple transmitters operating at the same time, the operators and licensees of which transmitters are responsible for mitigating over-exposure situations?

Select	Answer
A	Each transmitter that produces 5 percent or more of its MPE limit in areas where the total MPE limit is exceeded.
B	Each transmitter operating with a duty cycle greater than 50 percent
C	Only the most powerful transmitter
D	Only commercial transmitters

2. - E1A12

What special operating frequency restrictions are imposed on slow scan TV transmissions?

Select	Answer
A	They are not permitted above 54 MHz
B	They are restricted to 7.245 MHz, 14.245 MHz, 21.345 MHz, and 28.945 MHz
C	None; they are allowed on all amateur frequencies
D	They are restricted to phone band segments

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

4. - E1C09

What is the highest modulation index permitted at the highest modulation frequency for angle modulation below 29.0 MHz?

Select	Answer
A	3.0
B	2.0
C	1.0
D	0.5

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. - E1E10

What must the administering VEs do after the administration of a successful examination for an amateur operator license?

Select	Answer
A	They must collect and send the documents to the FCC according to instructions
B	They must collect and send the documents to the NCVEC for grading
C	They must submit the application document to the coordinating VEC according to the coordinating VEC instructions
D	They must collect and submit the documents to the coordinating VEC for grading

7. - E1F10

Who may be the control operator of an auxiliary station?

Select	Answer
A	Only General, Advanced or Amateur Extra Class operators
B	Any licensed amateur operator
C	Only Amateur Extra Class operators
D	Only Technician, General, Advanced or Amateur Extra Class operators

8. - E2A05

What do the letters in a satellite's mode designator specify?

Select	Answer
A	The uplink and downlink frequency ranges
B	Power limits for uplink and downlink transmissions
C	The polarization of uplink and downlink signals
D	The location of the ground control station

9. - E2B04

How is color information sent in analog SSTV?

Select	Answer
A	Color information is sent on a 2.8 kHz subcarrier
B	Color is amplitude modulated on the frequency modulated intensity signal
C	Color is sent in a color burst at the end of each line
D	Color lines are sent sequentially

10. - E2C11

How should you generally identify your station when attempting to contact a DX station during a contest or in a pileup?

Select	Answer
A	Send your full call sign and grid square
B	Send your full call sign once or twice
C	Send only the last two letters of your call sign until you make contact
D	Send the call sign of the DX station three times, the words this is,then your call sign three times

11. - E2D01

Which of the following digital modes is designed for meteor scatter communications?

Select	Answer
A	MSK144
B	APRS
C	Hellschreiber
D	WSPR

12. - E2E02

What do the letters FEC mean as they relate to digital operation?

Select	Answer
A	Forward Error Correction
B	Final Error Correction
C	Fatal Error Correction
D	First Error Correction

13. - E3A08

When a meteor strikes the Earth's atmosphere, a cylindrical region of free electrons is formed at what layer of the ionosphere?

Select	Answer
A	The E layer
B	The D layer
C	The F1 layer
D	The F2 layer

14. - E3B09

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

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

15. - E3C06

By how much does the VHF/UHF radio horizon distance exceed the geometric horizon?

Select	Answer
A	By approximately 50 percent of the distance
B	By approximately 15 percent of the distance
C	By approximately four times the distance
D	By approximately twice the distance

16. - E4A09

Which of the following is good practice when using an oscilloscope probe?

Select	Answer
A	Never use a DC-coupled probe to measure an AC circuit
B	All these choices are correct
C	Never use a high-impedance probe to measure a low-impedance circuit
D	Keep the signal ground connection of the probe as short as possible

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 harmonically related frequencies and observe the RF output with a logic 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 non-harmonically related frequencies and observe the RF output with a spectrum analyzer
D	Modulate the transmitter using two AF signals having non-harmonically related frequencies and observe the RF output with a spectrum analyzer

18. - E4C15

What is reciprocal mixing?

Select	Answer
A	In-phase signals cancelling in a mixer resulting in loss of receiver sensitivity
B	Two out-of-band signals mixing to generate an in-band spurious signal
C	Local oscillator phase noise mixing with adjacent strong signals to create interference to desired signals
D	Two digital signals combining from alternate time slots

19. - E4D06

What is the term for spurious signals generated by the combination of two or more signals in a non-linear device or circuit?

Select	Answer
A	Amplifier desensitization
B	Adjacent channel interference
C	Intermodulation
D	Neutralization

20. - E4E07

Which of the following can cause shielded cables to radiate or receive interference?

Select	Answer
A	Tying all ground connections to a common point resulting in differential-mode currents in the shield
B	Use of braided shielding material
C	Low inductance ground connections at both ends of the shield
D	Common-mode currents on the shield and conductors

21. - E5A13

What is an effect of increasing Q in a series resonant circuit?

Select	Answer
A	Internal voltages increase
B	Parasitic effects are minimized
C	Fewer components are needed for the same performance
D	Phase shift can become uncontrolled

22. - E5B09

What is the relationship between the AC current through a capacitor and the voltage across a capacitor?

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

23. - E5C02

How are impedances described in polar coordinates?

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

24. - E5D01

What is the result of skin effect?

Select	Answer
A	As frequency increases, RF current flows in a thinner layer of the conductor, closer to the surface
B	As frequency decreases, RF current flows in a thinner layer of the conductor, closer to the surface
C	Thermal effects on the surface of the conductor decrease the impedance
D	Thermal effects on the surface of the conductor increase the impedance

25. - E6A01

In what application is gallium arsenide used as a semiconductor material?

Select	Answer
A	In high-power audio circuits
B	In microwave circuits
C	In high-current rectifier circuits
D	In very low-frequency RF circuits

26. - E6B06

Which of the following is a common use of a Schottky diode?

Select	Answer
A	As a VHF/UHF mixer or detector
B	As a rectifier in high current power supplies
C	As a constant voltage reference in a power supply
D	As a variable capacitance in an automatic frequency control circuit

27. - E6C03

What is tri-state logic?

Select	Answer
A	Logic devices that utilize ternary math
B	Proprietary logic devices manufactured by Tri-State Devices
C	Logic devices with 0, 1, and high-impedance output states
D	Low-power logic devices designed to operate at 3 volts

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

29. - E6E05

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

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

30. - E6F08

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

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

31. - E7A09

What logical operation is performed by an exclusive NOR gate?

Select	Answer
A	It produces logic 1 at its output only if all inputs are logic 1
B	It produces logic 0 at its output only if all inputs are logic 0
C	It produces logic 0 at its output if only one input is logic 1
D	It produces logic 1 at its output if only one input is logic 1

32. - E7B02

What is a Class D amplifier?

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

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

34. - E7D05

Which of the following types of linear voltage regulator places a constant load on the unregulated voltage source?

Select	Answer
A	A constant current source
B	A series regulator
C	A shunt regulator
D	A shunt current source

35. - E7E09

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

Select	Answer
A	Mixer blanking occurs
B	Spurious mixer products are generated
C	Automatic limiting occurs
D	A beat frequency is 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 delay all frequency components of the signal by the same amount
B	FIR filters are easier to implement for a given set of passband rolloff requirements
C	FIR filters can respond faster to impulses
D	All these choices are correct

37. - E7G10

What absolute voltage gain can be expected from the circuit in Figure E7-3 when R1 is 1800 ohms and RF is 68 kilohms?

Select	Answer
A	76
B	0.03
C	1
D	38

38. - E7H15

Which of these functions can be performed by a phase-locked loop?

Select	Answer
A	Photovoltaic conversion, optical coupling
B	Frequency synthesis, FM demodulation
C	Wide-band AF and RF power amplification
D	Comparison of two digital input signals, digital pulse counter

39. - E8A04

What is "dither" with respect to analog-to-digital converters?

Select	Answer
A	A small amount of noise added to the input signal to allow more precise representation of a signal over time
B	An error caused by irregular quantization step size
C	A method of decimation by randomly skipping samples
D	An abnormal condition where the converter cannot settle on a value to represent the signal

40. - E8B09

What is deviation ratio?

Select	Answer
A	The ratio of the audio modulating frequency to the center carrier frequency
B	The ratio of the highest audio modulating frequency to the average audio modulating frequency
C	The ratio of the carrier center frequency to the audio modulating frequency
D	The ratio of the maximum carrier frequency deviation to the highest audio modulating frequency

41. - E8C05

What is the approximate bandwidth of a 13-WPM International Morse Code transmission?

Select	Answer
A	13 Hz
B	52 Hz
C	26 Hz
D	104 Hz

42. - E8D05

What is the most common method of reducing key clicks?

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

43. - E9A12

How much gain does an antenna have compared to a 1/2-wavelength dipole when it has 6 dB gain over an isotropic antenna?

Select	Answer
A	3.85 dB
B	8.15 dB
C	6.0 dB
D	2.79 dB

44. - E9B04

What is the front-to-back ratio of the radiation pattern shown in Figure E92?

Select	Answer
A	15 dB
B	38 dB
C	3 dB
D	28 dB

45. - E9C10

Which of the following describes a Zepp antenna?

Select	Answer
A	A dipole constructed from zip cord
B	An end-fed dipole antenna
C	A vertical array capable of quickly changing the direction of maximum radiation by changing phasing lines
D	An omni-directional antenna commonly used for satellite communications

46. - E9D06

What happens to the SWR bandwidth when one or more loading coils are used to resonate an electrically short antenna?

Select	Answer
A	It is decreased
B	It is increased
C	It is unchanged if the loading coil is located at a voltage maximum point
D	It is unchanged if the loading coil is located at the feed point

47. - E9E03

What is the name of the matching system that uses a section of transmission line connected in parallel with the feed line at or near the feed point?

Select	Answer
A	The delta match
B	The omega match
C	The gamma match
D	The stub match

48. - E9F04

What impedance does a 1/2-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 output impedance of the generator
C	Very high impedance
D	Very low impedance

49. - E9G09

What third family of circles is often added to a Smith chart during the process of solving problems?

Select	Answer
A	Radiation-pattern circles
B	Antenna-length circles
C	Standing wave ratio circles
D	Coaxial-length circles

50. - E9H05

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

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

Figure E7-3