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

2. - E1A12

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

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

3. - E1B04

What must be done before placing an amateur station within an officially designated wilderness area or wildlife preserve, or an area listed in the National Register of Historic Places?

Select	Answer
A	A proposal must be submitted to the National Park Service
B	A form FSD-15 must be submitted to the Department of the Interior
C	A letter of intent must be filed with the Environmental Protection Agency
D	An Environmental Assessment must be submitted to the FCC

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. - E1D03

What is a space telecommand station?

Select	Answer
A	An amateur station that receives telemetry from a satellite or balloon more than 50 kilometers above the surface of the Earth
B	An amateur station located in a satellite or a balloon more than 50 kilometers above the surface of the Earth
C	An amateur station located on the surface of the Earth for communication with other Earth stations by means of Earth satellites
D	An amateur station that transmits communications to initiate, modify or terminate functions of a space station

6. - E1E12

What must the VE team do with the application form if the examinee does not pass the exam?

Select	Answer
A	Return the application document to the examinee
B	Maintain the application form with the VEC's records
C	Destroy the application form
D	Send the application form to the FCC and inform the FCC of the grade

7. - E1F06

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

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

8. - E2A02

Which of the following occurs when a satellite is using an inverting linear transponder?

Select	Answer
A	Signal position in the band is reversed
B	All these choices are correct
C	Upper sideband on the uplink becomes lower sideband on the downlink, and vice versa
D	Doppler shift is reduced because the uplink and downlink shifts are in opposite directions

9. - E2B06

What is vestigial sideband modulation?

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

10. - E2C12

What technique do individual nodes use to form a mesh network?

Select	Answer
A	Forward error correction and Viterbi codes
B	Acting as store-and-forward digipeaters
C	Custom code plugs for the local trunking systems
D	Discovery and link establishment protocols

11. - E2D07

What digital protocol is used by APRS?

Select	Answer
A	AX.25
B	AMTOR
C	802.11
D	PACTOR

12. - E2E11

What is the difference between direct FSK and audio FSK?

Select	Answer
A	Direct FSK applies the data signal to the transmitter VFO, while AFSK transmits tones via phone
B	Only direct FSK can be decoded by computer
C	Direct FSK occupies less bandwidth
D	Direct FSK can transmit faster baud rates

13. - E3A12

What is the cause of auroral activity?

Select	Answer
A	An extreme low-pressure area in the polar regions
B	The interaction in the E layer of charged particles from the Sun with the Earth's magnetic field
C	Meteor showers concentrated in the extreme northern and southern latitudes
D	The interaction in the F2 layer between the solar wind and the Van Allen belt

14. - E3B10

Why is chordal hop propagation desirable?

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

15. - E3C12

How does the maximum range of ground-wave propagation change when the signal frequency is increased?

Select	Answer
A	It increases
B	It stays the same
C	It decreases
D	It peaks at roughly 14 MHz

16. - E4A02

Which of the following parameters does a spectrum analyzer display on the vertical and horizontal axes?

Select	Answer
A	SWR and time
B	RF amplitude and time
C	RF amplitude and frequency
D	SWR and frequency

17. - E4B03

Which S parameter is equivalent to forward gain?

Select	Answer
A	S21
B	S22
C	S11
D	S12

18. - E4C14

What transmit frequency might generate an image response signal in a receiver tuned to 14.300 MHz and that uses a 455 kHz IF frequency?

Select	Answer
A	14.445 MHz
B	15.210 MHz
C	13.845 MHz
D	14.755 MHz

19. - E4D08

What causes intermodulation in an electronic circuit?

Select	Answer
A	Too little gain
B	Positive feedback
C	Nonlinear circuits or devices
D	Lack of neutralization

20. - E4E04

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

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

21. - E5A08

What is the phase relationship between the current through and the voltage across a series resonant circuit at resonance?

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

22. - E5B02

What letter is commonly used to represent susceptance?

Select	Answer
A	G
B	X
C	Y
D	B

23. - E5C12

Which point on Figure E5-1 best represents the impedance of a series circuit consisting of a 300-ohm resistor and a 19-picofarad capacitor at 21.200 MHz?

Select	Answer
A	Point 7
B	Point 8
C	Point 1
D	Point 3

24. - E5D13

How many watts are consumed in a circuit consisting of a 100-ohm resistor in series with a 100-ohm inductive reactance drawing 1 ampere?

Select	Answer
A	70.7 watts
B	100 watts
C	200 watts
D	141.4 watts

25. - E6A09

What is a depletion-mode FET?

Select	Answer
A	An FET that has no current flow between source and drain when no gate voltage is applied
B	Any FET without a channel
C	Any FET for which holes are the majority carriers
D	An FET that exhibits a current flow between source and drain when no gate voltage is applied

26. - E6B06

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

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

27. - E6C06

Why do CMOS digital integrated circuits have high immunity to noise on the input signal or power supply?

Select	Answer
A	Large bypass capacitance is inherent
B	The input switching threshold is about two times the power supply voltage
C	Bandwidth is very limited
D	The input switching threshold is about one-half the power supply voltage

28. - E6D08

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

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

29. - E6E09

Which of the following component package types would be most suitable for use at frequencies above the HF range?

Select	Answer
A	Radial lead
B	Axial lead
C	Surface mount
D	TO-220

30. - E6F05

Which describes an optical shaft encoder?

Select	Answer
A	A device for generating RTTY signals by means of a rotating light source
B	A device that detects rotation of a control by interrupting a light source with a patterned wheel
C	A device that measures the strength of a beam of light using analog to digital conversion
D	A digital encryption device often used to encrypt spacecraft control signals

31. - E7A01

Which circuit is bistable?

Select	Answer
A	An OR gate
B	A bipolar amplifier
C	An AND gate
D	A flip-flop

32. - E7B03

Which of the following components form the output of a class D amplifier circuit?

Select	Answer
A	A low-pass filter to remove switching signal components
B	A high-pass filter to compensate for low gain at low frequencies
C	A matched load resistor to prevent damage by switching transients
D	A temperature compensating load resistor to improve linearity

33. - E7C01

How are the capacitors and inductors of a low-pass filter Pi-network arranged between the network's input and output?

Select	Answer
A	Two inductors are in series between the input and output, and a capacitor is connected between the two inductors and ground
B	Two capacitors are in series between the input and output, and an inductor is connected between the two capacitors and ground
C	A capacitor is connected between the input and ground, another capacitor is connected between the output and ground, and an inductor is connected between input and output
D	An inductor is connected between the input and ground, another inductor is connected between the output and ground, and a capacitor is connected between the input and output

34. - E7D06

What is the purpose of Q1 in the circuit shown in Figure E7-2?

Select	Answer
A	It provides negative feedback to improve regulation
B	It controls the current supplied to the load
C	It provides D1 with current
D	It provides a constant load for the voltage source

35. - E7E02

What is the function of a reactance modulator?

Select	Answer
A	To produce AM signals by using an electrically variable resistance
B	To produce PM signals by using an electrically variable resistance
C	To produce PM or FM signals by using an electrically variable inductance or capacitance
D	To produce AM signals by using an electrically variable inductance or capacitance

36. - E7F01

What is meant by direct digital conversion as applied to software defined radios?

Select	Answer
A	A switching mixer is used to generate I and Q signals directly from the RF input
B	Incoming RF is digitized by an analog-to-digital converter without being mixed with a local oscillator signal
C	Incoming RF is converted to a control voltage for a voltage controlled oscillator
D	Software is converted from source code to object code during operation of the receiver

37. - E7G08

How does the gain of an ideal operational amplifier vary with frequency?

Select	Answer
A	It decreases logarithmically with increasing frequency
B	It does not vary with frequency
C	It increases linearly with increasing frequency
D	It decreases linearly with increasing frequency

38. - E7H08

Which of the following components can be used to reduce thermal drift in crystal oscillators?

Select	Answer
A	Non-inductive resistors
B	NP0 capacitors
C	Toroidal inductors
D	Wirewound resistors

39. - E8A02

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

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

40. - E8B04

What is the modulation index of an FM-phone signal having a maximum carrier deviation of plus or minus 6 kHz when modulated with a 2 kHz modulating frequency?

Select	Answer
A	3
B	1/3
C	6000
D	2000

41. - E8C07

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

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

42. - E8D03

How does the spread spectrum technique of frequency hopping work?

Select	Answer
A	If interference is detected by the receiver it will signal the transmitter to wait until the frequency is clear
B	The frequency of the transmitted signal is changed very rapidly according to a pseudorandom sequence also used by the receiving station
C	A binary bit stream is used to shift the phase of an RF carrier very rapidly in a pseudorandom sequence
D	If interference is detected by the receiver it will signal the transmitter to change frequencies

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	252 watts
B	159 watts
C	63.2 watts
D	632 watts

44. - E9B01

In the antenna radiation pattern shown in Figure E9-1, what is the beamwidth?

Select	Answer
A	25 degrees
B	50 degrees
C	30 degrees
D	75 degrees

45. - E9C06

What is the effect of adding a terminating resistor to a rhombic antenna?

Select	Answer
A	It decreases the ground loss
B	It changes the radiation pattern from bidirectional to unidirectional
C	It changes the radiation pattern from horizontal to vertical polarization
D	It reflects the standing waves on the antenna elements back to the transmitter

46. - E9D05

What usually occurs if a Yagi antenna is designed solely for maximum forward gain?

Select	Answer
A	The front-to-back ratio increases
B	The SWR is reduced
C	The frequency response is widened over the whole frequency band
D	The front-to-back ratio decreases

47. - E9E11

What is the primary purpose of phasing lines when used with an antenna having multiple driven elements?

Select	Answer
A	It prevents reflected power from traveling back down the feed line and causing harmonic radiation from the transmitter
B	It ensures that each driven element operates in concert with the others to create the desired antenna pattern
C	It creates a low-angle radiation pattern
D	It allows single-band antennas to operate on other bands

48. - E9F13

What impedance does a 1/4-wavelength transmission line present to a generator when the line is shorted at the far end?

Select	Answer
A	Very high impedance
B	Very low impedance
C	The same as the generator output impedance
D	The same as the characteristic impedance of the transmission line

49. - E9G01

Which of the following can be calculated using a Smith chart?

Select	Answer
A	Radiation resistance
B	Antenna radiation pattern
C	Impedance along transmission lines
D	Radio propagation

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 has no clearly defined null
C	All these choices are correct
D	It is practical for use only on VHF and higher bands

Figure E5-1

Figure E7-2

Figure E9-1