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

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1. - E0A05

What is one of the potential hazards of operating in the amateur radio microwave bands?

Select	Answer
A	The high gain antennas commonly used can result in high exposure levels
B	The extremely high frequency energy can damage the joints of antenna structures
C	Microwaves often travel long distances by ionospheric reflection
D	Microwaves are ionizing radiation

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	14.349 MHz
B	14.100 MHz
C	14.149 MHz
D	14.070 MHz

3. - E1B02

Which of the following is an acceptable bandwidth for Digital Radio Mondiale (DRM) based voice or SSTV digital transmissions made on the HF amateur bands?

Select	Answer
A	20 kHz
B	10 kHz
C	15 kHz
D	3 kHz

4. - E1C06

Which of the following is required in order to operate in accordance with CEPT rules in foreign countries where permitted?

Select	Answer
A	You must identify in the official language of the country in which you are operating
B	The U.S. embassy must approve of your operation
C	You must append "/CEPT" to your call sign
D	You must bring a copy of FCC Public Notice DA 16-1048

5. - E1D05

What must be posted at the station location of a station being operated by telecommand on or within 50 km of the earth's surface?

Select	Answer
A	A label with the name, address, and telephone number of the control operator
B	A photocopy of the station license
C	All these choices are correct
D	A label with the name, address, and telephone number of the station licensee

6. - E1E06

Who is responsible for the proper conduct and necessary supervision during an amateur operator license examination session?

Select	Answer
A	The FCC
B	The VE session manager
C	The VEC coordinating the session
D	Each administering VE

7. - E1F01

On what frequencies are spread spectrum transmissions permitted?

Select	Answer
A	Only on amateur frequencies above 222 MHz
B	Only on amateur frequencies above 420 MHz
C	Only on amateur frequencies above 50 MHz
D	Only on amateur frequencies above 144 MHz

8. - E2A06

What are Keplerian elements?

Select	Answer
A	High-emission heater filaments used in magnetron tubes
B	Phase reversing elements in a Yagi antenna
C	Parameters that define the orbit of a satellite
D	Encrypting codes used for spread spectrum modulation

9. - E2B08

What technique allows commercial analog TV receivers to be used for fast-scan TV operations on the 70 cm band?

Select	Answer
A	Transmitting on the abandoned TV channel 2
B	Transmitting on channels shared with cable TV
C	Using USB and demodulating the signal with a computer sound card
D	Using converted satellite TV dishes

10. - E2C02

Which of the following best describes the term self-spotting? in connection with HF contest operating?

Select	Answer
A	An automatic method for rapidly zero beating or tuning to a station's frequency before calling that station
B	The often-prohibited practice of posting one's own call sign and frequency on a spotting network
C	A manual technique for rapidly zero beating or tuning to a station's frequency before calling that station
D	The acceptable practice of manually posting the call signs of stations on a spotting network

11. - E2D04

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

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

12. - E2E03

How is the timing of FT4 contacts organized?

Select	Answer
A	Stations take turns on alternate days
B	It depends on the lunar phase
C	Alternating transmissions at 7.5 second intervals
D	By exchanging ACK/NAK packets

13. - E3A11

What is a typical range for tropospheric propagation of microwave signals?

Select	Answer
A	2500 miles
B	10 miles to 50 miles
C	1200 miles
D	100 miles to 300 miles

14. - E3B07

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

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

15. - E3C01

What does the radio communication term "ray tracing" describe?

Select	Answer
A	The process in which an electronic display presents a pattern
B	Evaluating high voltage sources for x-rays
C	Determining the radiation pattern from an array of antennas
D	Modeling a radio wave's path through the ionosphere

16. - E4A01

Which of the following limits the highest frequency signal that can be accurately displayed on a digital oscilloscope?

Select	Answer
A	Q of the circuit
B	All these choices are correct
C	Amount of memory
D	Sampling rate of the analog-to-digital converter

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

18. - E4C12

Which of the following has the largest effect on an SDR receiver's dynamic range?

Select	Answer
A	RAM speed used for data storage
B	Analog-to-digital converter sample width in bits
C	CPU register width in bits
D	Anti-aliasing input filter bandwidth

19. - E4D11

Why are odd-order intermodulation products, created within a receiver, of particular interest compared to other products?

Select	Answer
A	Odd-order products overload the IF filters
B	Odd-order products of two signals in the band of interest are also likely to be within the band
C	Odd-order intermodulation produces three products for every input signal within the band of interest
D	Odd-order products are an indication of poor image rejection

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

21. - E5A06

What is the magnitude of the circulating current within the components of a parallel LC circuit at resonance?

Select	Answer
A	It equals 1 divided by the quantity 2 times pi, multiplied by the square root of inductance L multiplied by capacitance C
B	It is at a maximum
C	It is at a minimum
D	It equals 2 multiplied by pi, multiplied by frequency, multiplied by inductance

22. - E5B06

What is susceptance?

Select	Answer
A	The imaginary part of admittance
B	The ratio of magnetic field to electric field
C	A measure of the efficiency of a transformer
D	The magnetic impedance of a circuit

23. - E5C03

Which of the following represents an inductive reactance in polar coordinates?

Select	Answer
A	A positive magnitude
B	A negative phase angle
C	A positive phase angle
D	A negative magnitude

24. - E5D08

How many watts are consumed in a circuit having a power factor of 0.6 if the input is 200VAC at 5 amperes?

Select	Answer
A	600 watts
B	200 watts
C	1000 watts
D	1600 watts

25. - E6A06

What is the beta of a bipolar junction transistor?

Select	Answer
A	The frequency at which the current gain is reduced to 0.707
B	The change in collector current with respect to base current
C	The switching speed
D	The breakdown voltage of the base to collector junction

26. - E6B03

What type of bias is required for an LED to emit light?

Select	Answer
A	Zero bias
B	Reverse bias
C	Inductive bias
D	Forward bias

27. - E6C03

What is tri-state logic?

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

28. - E6D11

Which type of core material decreases inductance when inserted into a coil?

Select	Answer
A	Ferrite
B	Powdered iron
C	Ceramic
D	Brass

29. - E6E08

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

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

30. - E6F05

Which describes an optical shaft encoder?

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

31. - E7A10

What is a truth table?

Select	Answer
A	A diagram showing logic states when the digital device output is true
B	A table of logic symbols that indicate the high logic states of an op-amp
C	A list of inputs and corresponding outputs for a digital device
D	A table of logic symbols that indicate the logic states of an op-amp

32. - E7B18

What is a characteristic of a grounded-grid amplifier?

Select	Answer
A	High filament voltage
B	Low input impedance
C	Low bandwidth
D	High power gain

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

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 shunt current source
C	A series regulator
D	A shunt regulator

35. - E7E09

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

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

36. - E7F07

What function is performed by a Fast Fourier Transform?

Select	Answer
A	Converting 8-bit data to 16-bit data
B	Converting digital signals to analog form
C	Converting analog signals to digital form
D	Converting digital signals from the time domain to the frequency domain

37. - E7G01

What is the typical output impedance of an op-amp?

Select	Answer
A	Very low
B	100 ohms
C	Very high
D	1000 ohms

38. - E7H14

What is a phase-locked loop circuit?

Select	Answer
A	An electronic circuit also known as a monostable multivibrator
B	An electronic servo loop consisting of a ratio detector, reactance modulator, and voltage-controlled oscillator
C	An electronic servo loop consisting of a phase detector, a low-pass filter, a voltage-controlled oscillator, and a stable reference oscillator
D	An electronic circuit consisting of a precision push-pull amplifier with a differential input

39. - E8A09

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

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

40. - E8B09

What is deviation ratio?

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

41. - E8C08

How does ARQ accomplish error correction?

Select	Answer
A	Special binary codes provide automatic correction
B	If errors are detected, redundant data is substituted
C	Special polynomial codes provide automatic correction
D	If errors are detected, a retransmission is requested

42. - E8D09

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

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

43. - E9A04

Which of the following factors affect the feed point impedance of an antenna?

Select	Answer
A	The settings of an antenna tuner at the transmitter
B	The input power level
C	Antenna height
D	Transmission line length

44. - E9B03

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

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

45. - E9C09

Which of the following describes a G5RV antenna?

Select	Answer
A	A multi-band trap antenna
B	A multi-band dipole antenna fed with coax and a balun through a selected length of open wire transmission line
C	A phased array antenna consisting of multiple loops
D	A wide band dipole using shorted coaxial cable for the radiating elements and fed with a�4:1 balun

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

47. - E9E02

What is the name of an antenna matching system that matches an unbalanced feed line to an antenna by feeding the driven element both at the center of the element and at a fraction of a wavelength to one side of center?

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

48. - E9F05

What is the approximate physical length of a solid polyethylene dielectric coaxial transmission line that is electrically 1/4 wavelength long at 14.1 MHz?

Select	Answer
A	5.3 meters
B	4.3 meters
C	3.5 meters
D	10.6 meters

49. - E9G02

What type of coordinate system is used in a Smith chart?

Select	Answer
A	Voltage lines and current chords
B	Resistance circles and reactance arcs
C	Resistance lines and reactance chords
D	Voltage circles and current arcs

50. - E9H08

What is the function of a sense antenna?

Select	Answer
A	It provides diversity reception that cancels multipath signals
B	It modifies the pattern of a DF antenna array to provide a null in one direction
C	It allows DF antennas to receive signals at different vertical angles
D	It increases the sensitivity of a DF antenna array

Figure E9-1