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

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1. - E0A06

Why are there separate electric (E) and magnetic (H) field MPE limits?

Select	Answer
A	All these choices are correct
B	The body reacts to electromagnetic radiation from both the E and H fields
C	E field and H field radiation intensity peaks can occur at different locations
D	Ground reflections and scattering make the field strength vary with location

2. - E1A03

What is the maximum legal carrier frequency on the 20 meter band for transmitting USB AFSK digital signals having a 1 kHz bandwidth?

Select	Answer
A	14.070 MHz
B	14.149 MHz
C	14.100 MHz
D	14.349 MHz

3. - E1B11

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

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

4. - E1C11

Which of the following operating arrangements allows an FCC-licensed U.S. citizen to operate in many European countries, and alien amateurs from many European countries to operate in the U.S.?

Select	Answer
A	ITU reciprocal license
B	IARP agreement
C	All these choices are correct
D	CEPT agreement

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	Binary control characters
C	Data containing personal information
D	Auxiliary relay links carrying repeater audio

6. - E1E12

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

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

7. - E1F10

Who may be the control operator of an auxiliary station?

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

8. - E2A12

What is the purpose of digital store-and-forward functions on an amateur radio satellite?

Select	Answer
A	To delay download of telemetry between satellites
B	To upload operational software for the transponder
C	To store digital messages in the satellite for later download by other stations
D	To relay messages between satellites

9. - E2B04

How is color information sent in analog SSTV?

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

10. - E2C01

What indicator is required to be used by U.S.-licensed operators when operating a station via remote control and the remote transmitter is located in the U.S.?

Select	Answer
A	No additional indicator is required
B	/R# where # is the district of the remote station
C	/ followed by the USPS two-letter abbreviation for the state in which the remote station is located
D	/ followed by the ARRL Section of the remote station

11. - E2D02

Which of the following is a good technique for making meteor scatter contacts?

Select	Answer
A	15-second timed transmission sequences with stations alternating based on location
B	Use of special digital modes
C	All these choices are correct
D	Short transmissions with rapidly repeated call signs and signal reports

12. - E2E01

Which of the following types of modulation is common for data emissions below 30 MHz?

Select	Answer
A	Spread spectrum
B	FSK
C	DTMF tones modulating an FM signal
D	Pulse modulation

13. - E3A06

What might help to restore contact when DX signals become too weak to copy across an entire HF band a few hours after sunset?

Select	Answer
A	Wait 24 hours before attempting another communication on the band
B	Switch to a higher frequency HF band
C	Switch to a lower frequency HF band
D	Wait 90 minutes or so for the signal degradation to pass

14. - E3B07

What happens to linearly polarized radio waves that split into ordinary and extraordinary waves in the ionosphere?

Select	Answer
A	They become depolarized
B	They are bent toward the magnetic poles
C	They become elliptically polarized
D	They become phase locked

15. - E3C07

Which of the following descriptors indicates the greatest solar flare intensity?

Select	Answer
A	Class X
B	Class B
C	Class A
D	Class M

16. - E4A04

How is the compensation of an oscilloscope probe typically adjusted?

Select	Answer
A	A DC voltage standard is displayed and the probe is adjusted until the displayed voltage is accurate
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 high frequency sine wave is displayed and the probe is adjusted for maximum amplitude

17. - E4B01

Which of the following factors most affects the accuracy of a frequency counter?

Select	Answer
A	Temperature coefficient of the logic
B	Time base accuracy
C	Input attenuator accuracy
D	Decade divider accuracy

18. - E4C10

What is an advantage of having a variety of receiver IF bandwidths from which to select?

Select	Answer
A	Receiver power consumption can be reduced when wider bandwidth is not required
B	The noise figure of the RF amplifier can be adjusted to match the modulation type, thus increasing receiver sensitivity
C	Multiple frequencies can be received simultaneously if desired
D	Receive bandwidth can be set to match the modulation bandwidth, maximizing signal-to-noise ratio and minimizing interference

19. - E4D09

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

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

20. - E4E05

How can radio frequency interference from an AC motor be suppressed?

Select	Answer
A	By installing a bypass capacitor in series with the motor leads
B	By installing a high-pass filter in series with the motor's power leads
C	By using a ground-fault current interrupter in the circuit used to power the motor
D	By installing a brute-force AC-line filter in series with the motor leads

21. - E5A03

What is the magnitude of the impedance of a series RLC circuit at resonance?

Select	Answer
A	High, as compared to the circuit resistance
B	Approximately equal to capacitive reactance
C	Approximately equal to circuit resistance
D	Approximately equal to inductive reactance

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	Current leads voltage by 90 degrees
C	Voltage and current are in phase
D	Voltage leads current by 90 degrees

23. - E5C06

What does the impedance 50-j25 represent?

Select	Answer
A	50 ohms resistance in series with 25 ohms capacitive reactance
B	25 ohms resistance in series with 50 ohms capacitive reactance
C	25 ohms resistance in series with 50 ohms inductive reactance
D	50 ohms resistance in series with 25 ohms inductive reactance

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	50 watts
B	80 watts
C	2000 watts
D	400 watts

25. - E6A08

What term indicates the frequency at which the grounded-base current gain of a transistor has decreased to 0.7 of the gain obtainable at 1 kHz?

Select	Answer
A	Corner frequency
B	Alpha cutoff frequency
C	Alpha rejection frequency
D	Beta cutoff frequency

26. - E6B08

Which of the following is a Schottky barrier diode?

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

27. - E6C07

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

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

28. - E6D01

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

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

29. - E6E03

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

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

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

31. - E7A03

Which of the following can divide the frequency of a pulse train by 2?

Select	Answer
A	A flip-flop
B	An OR gate
C	A multiplexer
D	An XOR gate

32. - E7B09

Which of the following describes how the loading and tuning capacitors are to be adjusted when tuning a vacuum tube RF power amplifier that employs a Pi-network output circuit?

Select	Answer
A	The loading capacitor is set to maximum capacitance and the tuning capacitor is adjusted for minimum allowable plate current
B	The loading capacitor is adjusted to minimum plate current while alternately adjusting the tuning capacitor for maximum allowable plate current
C	The tuning capacitor is adjusted for minimum plate current, and the loading capacitor is adjusted for maximum permissible plate current
D	The tuning capacitor is set to maximum capacitance and the loading capacitor is adjusted for minimum plate permissible current

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 capacitors are in series between the input and output, and an inductor is connected between the two capacitors and ground
B	Two inductors are in series between the input and output, and a capacitor is connected between the two inductors 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. - 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 gives a ramp voltage at its output
C	The controlled device's duty cycle is changed to produce a constant average output voltage
D	It is generally less efficient than a linear regulator

35. - E7E09

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

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

36. - E7F08

What is the function of decimation?

Select	Answer
A	Attenuating the signal
B	Reducing the effective sample rate by removing samples
C	Removing unnecessary significant digits
D	Converting data to binary code decimal form

37. - E7G07

What magnitude of voltage gain can be expected from the circuit in Figure E73 when R1 is 10 ohms and RF is 470 ohms?

Select	Answer
A	94
B	47
C	0.21
D	24

38. - E7H08

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

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

39. - E8A09

How many different input levels can be encoded by an analog-to-digital converter with 8-bit resolution?

Select	Answer
A	256
B	8
C	256 divided by the gain of the input amplifier
D	8 multiplied by the gain of the input amplifier

40. - E8B08

What describes Orthogonal Frequency Division Multiplexing?

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

41. - E8C05

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

Select	Answer
A	52 Hz
B	26 Hz
C	13 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	Low-pass filters at the transmitter output
C	Increase keying waveform rise and fall times
D	High-pass filters at the transmitter output

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

44. - E9B09

What type of computer program technique is commonly used for modeling antennas?

Select	Answer
A	Mutual impedance analysis
B	Graphical analysis
C	Method of Moments
D	Calculus differentiation with respect to physical properties

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 takeoff angle of the lowest elevation lobe decreases
C	The horizontal beamwidth decreases
D	The takeoff angle of the lowest elevation lobe increases

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 front-to-back ratio decreases
C	The frequency response is widened over the whole frequency band
D	The SWR is reduced

47. - E9E05

How must an antenna's driven element be tuned to use a hairpin matching system?

Select	Answer
A	The driven element radiation resistance must be higher than the characteristic impedance of the transmission line
B	The driven element reactance must be inductive
C	The driven element reactance must be capacitive
D	The driven element resonance must be lower than the operating frequency

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 low impedance
D	Very high impedance

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. - E9H04

What is an advantage of placing a grounded electrostatic shield around a small loop direction-finding antenna?

Select	Answer
A	It increases signal strength by providing a better match to the feed line
B	It adds capacitive loading, increasing the bandwidth of the antenna
C	It eliminates unbalanced capacitive coupling to the surroundings, improving the nulls
D	It eliminates tracking errors caused by strong out-of-band signals