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	E field and H field radiation intensity peaks can occur at different locations
C	Ground reflections and scattering make the field strength vary with location
D	The body reacts to electromagnetic radiation from both the E and H fields

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

3. - E1B05

What is the National Radio Quiet Zone?

Select	Answer
A	An area in Puerto Rico surrounding the Arecibo Radio Telescope
B	An area in Florida surrounding Cape Canaveral
C	An area in New Mexico surrounding the White Sands Test Area
D	An area surrounding the National Radio Astronomy Observatory

4. - E1C09

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

Select	Answer
A	1.0
B	0.5
C	2.0
D	3.0

5. - E1D07

Which HF amateur bands have frequencies authorized for space stations?

Select	Answer
A	Only the 40, 20, 17, 15, 12, and 10 meter bands
B	All HF bands
C	Only the 40, 30, 20, 15, 12, and 10 meter bands
D	Only the 40, 20, 17, 15, and 10 meter bands

6. - E1E08

To which of the following examinees may a VE not administer an examination?

Select	Answer
A	Friends of the VE
B	Relatives of the VE as listed in the FCC rules
C	All these choices are correct
D	Employees of the VE

7. - E1F09

Which of the following conditions apply when transmitting spread spectrum emissions?

Select	Answer
A	All these choices are correct
B	The transmitting station must be in an area regulated by the FCC or in a country that permits SS emissions
C	A station transmitting SS emission must not cause harmful interference to other stations employing other authorized emissions
D	The transmission must not be used to obscure the meaning of any communication

8. - E2A08

Why should effective radiated power to a satellite that uses a linear transponder be limited?

Select	Answer
A	To avoid reducing the downlink power to all other users
B	To avoid interfering with terrestrial QSOs
C	To prevent the satellite from emitting out-of-band signals
D	To prevent creating errors in the satellite telemetry

9. - E2B06

What is vestigial sideband modulation?

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

10. - E2C09

What type of equipment is commonly used to implement an amateur radio mesh network?

Select	Answer
A	A wireless router running custom firmware
B	A 2 meter VHF transceiver with a 1200 baud modem
C	An optical cable connection between the USB ports of 2 separate computers
D	A 440 MHz transceiver with a 9600 baud modem

11. - E2D01

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

Select	Answer
A	APRS
B	MSK144
C	Hellschreiber
D	WSPR

12. - E2E08

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

Select	Answer
A	AMTOR
B	Hellschreiber
C	RTTY
D	PACTOR

13. - E3A05

Tropospheric propagation of microwave signals often occurs in association with what phenomenon?

Select	Answer
A	Warm and cold fronts
B	Grayline
C	Sprites and jets
D	Lightning discharges

14. - E3B10

Why is chordal hop propagation desirable?

Select	Answer
A	Signals travel faster along ionospheric chords
B	The signal experiences less loss compared to multi-hop using Earth as a reflector
C	Atmospheric noise is lower in the direction of chordal hop propagation
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	Westward
B	Eastward
C	Northward
D	Southward

16. - E4A02

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

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

17. - E4B09

What is indicated if the current reading on an RF ammeter placed in series with the antenna feed line of a transmitter increases as the transmitter is tuned to resonance?

Select	Answer
A	The transmitter is not properly neutralized
B	There is more power going into the antenna
C	There is an impedance mismatch between the antenna and feed line
D	There is possibly a short to ground in the feed line

18. - E4C05

What does a receiver noise floor of -174 dBm represent?

Select	Answer
A	The galactic noise contribution to minimum detectable signal
B	The minimum detectable signal as a function of receive frequency
C	The theoretical noise in a 1 Hz bandwidth at the input of a perfect receiver at room temperature
D	The noise figure of a 1 Hz bandwidth receiver

19. - E4D02

Which of the following describes problems caused by poor dynamic range in a receiver?

Select	Answer
A	Cross-modulation of the desired signal and insufficient audio power to operate the speaker
B	Spurious signals caused by cross-modulation and desensitization from strong adjacent signals
C	Oscillator instability and severe audio distortion of all but the strongest received signals
D	Oscillator instability requiring frequent retuning and loss of ability to recover the opposite sideband

20. - E4E03

Which of the following signals might a receiver noise blanker be able to remove from desired signals?

Select	Answer
A	Signals that appear across a wide bandwidth
B	Signals that appear at one IF but not another
C	Signals that are constant at all IF levels
D	Signals that have a sharply peaked frequency distribution

21. - E5A07

What is the magnitude of the current at the input of a parallel RLC circuit at resonance?

Select	Answer
A	R/L
B	Maximum
C	L/R
D	Minimum

22. - E5B02

What letter is commonly used to represent susceptance?

Select	Answer
A	B
B	Y
C	G
D	X

23. - E5C10

Which point on Figure E5-1 best represents the impedance of a series circuit consisting of a 400-ohm resistor and a 38-picofarad capacitor at 14 MHz?

Select	Answer
A	Point 4
B	Point 6
C	Point 5
D	Point 2

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	2000 watts
B	50 watts
C	80 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	Beta cutoff frequency
B	Corner frequency
C	Alpha cutoff frequency
D	Alpha rejection frequency

26. - E6B02

What is an important characteristic of a Schottky diode as compared to an ordinary silicon diode when used as a power supply rectifier?

Select	Answer
A	Longer carrier retention time
B	Much higher reverse voltage breakdown
C	Less forward voltage drop
D	More constant reverse avalanche voltage

27. - E6C09

What is a Programmable Logic Device (PLD)?

Select	Answer
A	A programmable collection of logic gates and circuits in a single integrated circuit
B	A type of transistor whose gain can be changed by digital logic circuits
C	Programmable equipment used for testing digital logic integrated circuits
D	A logic circuit that can be modified during use

28. - E6D12

What is inductor saturation?

Select	Answer
A	Adjacent inductors become over-coupled
B	The inductor's voltage rating is exceeded causing a flashover
C	The ability of the inductor's core to store magnetic energy has been exceeded
D	The inductor windings are over-coupled

29. - E6E08

How is power supplied to the most common type of MMIC?

Select	Answer
A	Through a resistor and/or RF choke connected to the amplifier output lead
B	Directly to the bias voltage (VCC IN) lead
C	MMICs require no operating bias
D	Through a capacitor and RF choke connected to the amplifier input lead

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. - E7A02

What is the function of a decade counter?

Select	Answer
A	It decodes a decimal number for display on a seven-segment LED display
B	It produces 10 output pulses for every input pulse
C	It decodes a binary number for display on a seven-segment LED display
D	It produces one output pulse for every 10 input pulses

32. - E7B05

What can be done to prevent unwanted oscillations in an RF power amplifier?

Select	Answer
A	Use a phase inverter in the output filter
B	Install parasitic suppressors and/or neutralize the stage
C	Tune the stage for maximum SWR
D	Tune both the input and output for maximum power

33. - E7C06

What are the distinguishing features of an elliptical filter?

Select	Answer
A	Extremely flat response over its pass band with gradually rounded stop band corners
B	Extremely sharp cutoff with one or more notches in the stop band
C	Gradual passband rolloff with extreme stop band ripple
D	Gradual passband rolloff with minimal stop band ripple

34. - E7D01

How does a linear electronic voltage regulator work?

Select	Answer
A	It eliminates the need for a pass transistor
B	It has a ramp voltage as its output
C	The control element duty cycle is proportional to the line or load conditions
D	The conduction of a control element is varied to maintain a constant output voltage

35. - E7E05

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

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

36. - E7F01

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

Select	Answer
A	Software is converted from source code to object code during operation of the receiver
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	A switching mixer is used to generate I and Q signals directly from the RF input

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	24
D	0.21

38. - E7H15

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

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

39. - E8A01

What is the name of the process that shows that a square wave is made up of a sine wave plus all its odd harmonics?

Select	Answer
A	Numerical analysis
B	Vector analysis
C	Fourier analysis
D	Differential analysis

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 carrier center frequency to the audio modulating frequency
C	The ratio of the highest audio modulating frequency to the average 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	52 Hz
B	26 Hz
C	104 Hz
D	13 Hz

42. - E8D06

What is the advantage of including parity bits in ASCII characters?

Select	Answer
A	Foreign language characters can be sent
B	Faster transmission rate
C	Some types of errors can be detected
D	The signal can overpower interfering signals

43. - E9A03

What is the radiation resistance of an antenna?

Select	Answer
A	The combined losses of the antenna elements and feed line
B	The resistance in the atmosphere that an antenna must overcome to be able to radiate a signal
C	The value of a resistance that would dissipate the same amount of power as that radiated from an antenna
D	The specific impedance of the antenna

44. - E9B03

In the antenna radiation pattern shown in Figure E9-1, what is the front-to-side ratio?

Select	Answer
A	12 dB
B	18 dB
C	14 dB
D	24 dB

45. - E9C05

Which of the following is a type of OCFD antenna?

Select	Answer
A	A multiband dipole antenna using one-way circular polarization for frequency diversity
B	A remotely tunable dipole antenna using orthogonally controlled frequency diversity
C	A folded dipole center-fed with 300-ohm transmission line
D	A dipole fed approximately 1/3 the way from one end with a 4:1 balun to provide multiband operation

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 unchanged if the loading coil is located at the feed point
C	It is unchanged if the loading coil is located at a voltage maximum point
D	It is increased

47. - E9E08

What is a use for a Wilkinson divider?

Select	Answer
A	It is used to feed low-impedance loads from a high-impedance source
B	It is used to divide power equally between two 50-ohm loads while maintaining 50-ohm input impedance
C	It divides the operating frequency of a transmitter signal so it can be used on a lower frequency band
D	It is used to feed high-impedance antennas from a low-impedance source

48. - E9F03

Why is the physical length of a coaxial cable transmission line shorter than its electrical length?

Select	Answer
A	The surge impedance is higher in a parallel feed line
B	The characteristic impedance is higher in a parallel feed line
C	Electrical signals move more slowly in a coaxial cable than in air
D	Skin effect is less pronounced in the coaxial cable

49. - E9G04

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

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

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

Figure E5-1

Figure E9-1