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

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1. - E0A11

Which of the following injuries can result from using high-power UHF or microwave transmitters?

Select	Answer
A	Ingestion of ozone gas from the cooling system
B	Hearing loss caused by high voltage corona discharge
C	Blood clotting from the intense magnetic field
D	Localized heating of the body from RF exposure in excess of the MPE limits

2. - E1A11

Which of the following describes authorization or licensing required when operating an amateur station aboard a U.S.-registered vessel in international waters?

Select	Answer
A	Any FCC-issued amateur license
B	An unrestricted Radiotelephone Operator Permit
C	Any amateur license with an FCC Marine or Aircraft endorsement
D	Only General Class or higher amateur licenses

3. - E1B07

To what type of regulations does PRB-1 apply?

Select	Answer
A	Homeowners associations
B	FAA tower height limits
C	State and local zoning
D	Use of wireless devices in vehicles

4. - E1C05

When may an automatically controlled station originate third party communications?

Select	Answer
A	When agreed upon by the sending or receiving station
B	Never
C	Only when transmitting RTTY or data emissions
D	When approved by the National Telecommunication and Information Administration

5. - E1D04

Which of the following is required in the identification transmissions from a balloon-borne telemetry station?

Select	Answer
A	The output power of the balloon transmitter
B	The station's six-character Maidenhead grid locator
C	All these choices are correct
D	Call sign

6. - E1E09

What may be the penalty for a VE who fraudulently administers or certifies an examination?

Select	Answer
A	Revocation of the VE's amateur station license grant and the suspension of the VE's amateur operator license grant
B	A fine of up to $1000 per occurrence
C	All these choices are correct
D	A sentence of up to one year in prison

7. - E1F07

When may an amateur station send a message to a business?

Select	Answer
A	When transmitting international third-party communications
B	When the control operator is employed by the FCC or another government agency
C	When neither the amateur nor his or her employer has a pecuniary interest in the communications
D	When the total money involved does not exceed $25

8. - E2A08

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

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

9. - E2B04

How is color information sent in analog SSTV?

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

10. - E2C10

Why might a DX station state that they are listening on another frequency?

Select	Answer
A	All these choices are correct
B	Because the DX station may be transmitting on a frequency that is prohibited to some responding stations
C	To improve operating efficiency by reducing interference
D	To separate the calling stations from the DX station

11. - E2D01

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

Select	Answer
A	Hellschreiber
B	APRS
C	WSPR
D	MSK144

12. - E2E09

Which of the following HF digital modes uses variable-length coding for bandwidth efficiency?

Select	Answer
A	PSK31
B	MT63
C	PACTOR
D	RTTY

13. - E3A01

What is the approximate maximum separation measured along the surface of the Earth between two stations communicating by EME?

Select	Answer
A	500 miles, if the moon is at perigee
B	5000 miles, if the moon is at perigee
C	12,000 miles, if the moon is visible by both stations
D	2000 miles, if the moon is at apogee

14. - E3B06

Which of the following amateur bands most frequently provides long-path propagation?

Select	Answer
A	6 meters
B	10 meters
C	20 meters
D	80 meters

15. - E3C14

Why does the radio-path horizon distance exceed the geometric horizon?

Select	Answer
A	Due to the Doppler effect
B	Downward bending due to density variations in the atmosphere
C	E-region skip
D	D-region skip

16. - E4A06

What is the effect of aliasing on a digital oscilloscope caused by setting the time base too slow?

Select	Answer
A	Calibration of the vertical scale is no longer valid
B	A false, jittery low-frequency version of the signal is displayed
C	All signals will have a DC offset
D	Excessive blanking occurs, which prevents display of the signal

17. - E4B02

What is the significance of voltmeter sensitivity expressed in ohms per volt?

Select	Answer
A	The full scale reading of the voltmeter multiplied by its ohms per volt rating will indicate the input impedance of the voltmeter
B	When used as an ammeter, the full scale reading in amps divided by ohms per volt rating will determine the size of shunt needed
C	When used as an ohmmeter, the reading in ohms divided by the ohms per volt rating will determine the voltage applied to the circuit
D	When used as a galvanometer, the reading in volts multiplied by the ohms per volt rating will determine the power drawn by the device under test

18. - E4C01

What is an effect of excessive phase noise in a receiver's local oscillator?

Select	Answer
A	It can affect the receiver's frequency calibration
B	It decreases receiver third-order intercept point
C	It can combine with strong signals on nearby frequencies to generate interference
D	It limits the receiver's ability to receive strong signals

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	Intermodulation
C	Adjacent channel interference
D	Neutralization

20. - E4E07

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

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

21. - E5A12

What is the half-power bandwidth of a resonant circuit that has a resonant frequency of 3.7 MHz and a Q of 118?

Select	Answer
A	218.3 kHz
B	31.4 kHz
C	436.6 kHz
D	15.7 kHz

22. - E5B11

What is the phase angle between the voltage across and the current through a series RLC circuit if XC is 25 ohms, R is 100 ohms, and XL is 50 ohms?

Select	Answer
A	76 degrees with the voltage lagging the current
B	14 degrees with the voltage lagging the current
C	76 degrees with the voltage leading the current
D	14 degrees with the voltage leading the current

23. - E5C01

Which of the following represents capacitive reactance in rectangular notation?

Select	Answer
A	+jX
B	Delta
C	Omega
D	-jX

24. - E5D04

Why are short connections used at microwave frequencies?

Select	Answer
A	To reduce noise figure
B	To increase neutralizing resistance
C	To reduce phase shift along the connection
D	To increase compensating capacitance

25. - E6A03

Why does a PN-junction diode not conduct current when reverse biased?

Select	Answer
A	Only N-type semiconductor material can conduct current
B	Only P-type semiconductor material can conduct current
C	Excess holes in P-type material combine with the electrons in N-type material, converting the entire diode into an insulator
D	Holes in P-type material and electrons in the N-type material are separated by the applied voltage, widening the depletion region

26. - E6B05

What characteristic of a PIN diode makes it useful as an RF switch?

Select	Answer
A	Low junction capacitance
B	Extremely high reverse breakdown voltage
C	Reverse bias controls its forward voltage drop
D	Ability to dissipate large amounts of power

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	The input switching threshold is about one-half the power supply voltage
D	Bandwidth is very limited

28. - E6D03

Which of the following is an aspect of the piezoelectric effect?

Select	Answer
A	Mechanical deformation of material by the application of a magnetic field
B	Increased conductivity in the presence of light
C	Mechanical deformation of material by the application of a voltage
D	Generation of electrical energy in the presence of light

29. - E6E05

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

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

30. - E6F04

What is the photovoltaic effect?

Select	Answer
A	The conversion of voltage to current when exposed to light
B	The tendency of a battery to discharge when exposed to light
C	The conversion of light to electrical energy
D	The conversion of electrical energy to mechanical energy

31. - E7A01

Which circuit is bistable?

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

32. - E7B04

Where on the load line of a Class A common emitter amplifier would bias normally be set?

Select	Answer
A	At a point where the load line intersects the zero bias current curve
B	Approximately halfway between saturation and cutoff
C	Where the load line intersects the voltage axis
D	At a point where the bias resistor equals the load resistor

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. - E7D06

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

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

35. - E7E04

What is one way a single-sideband phone signal can be generated?

Select	Answer
A	By driving a product detector with a DSB signal
B	By using a balanced modulator followed by a filter
C	By using a reactance modulator followed by a mixer
D	By using a loop modulator followed by a mixer

36. - E7F05

How frequently must an analog signal be sampled by an analog-to-digital converter so that the signal can be accurately reproduced?

Select	Answer
A	At the same rate as the highest frequency component of the signal
B	At least twice the rate of the highest frequency component of the signal
C	At four times the rate of the highest frequency component of the signal
D	At least half the rate of the highest frequency component of the signal

37. - E7G09

What will be the output voltage of the circuit shown in Figure E7-3 if R1 is 1000 ohms, RF is 10,000 ohms, and 0.23 volts DC is applied to the input?

Select	Answer
A	0.23 volts
B	-2.3 volts
C	-0.23 volts
D	2.3 volts

38. - E7H06

Which of the following oscillator circuits are commonly used in VFOs?

Select	Answer
A	Colpitts and Hartley
B	Armstrong and deForest
C	Negative feedback and balanced feedback
D	Pierce and Zener

39. - E8A08

Why would a direct or flash conversion analog-to-digital converter be useful for a software defined radio?

Select	Answer
A	Immunity to out-of-sequence coding reduces spurious responses
B	All these choices are correct
C	Very high speed allows digitizing high frequencies
D	Very low power consumption decreases frequency drift

40. - E8B08

What describes Orthogonal Frequency Division Multiplexing?

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

41. - E8C10

How may data rate be increased without increasing bandwidth?

Select	Answer
A	Increasing analog-to-digital conversion resolution
B	Using a more efficient digital code
C	Using forward error correction
D	It is impossible

42. - E8D07

What is a common cause of overmodulation of AFSK signals?

Select	Answer
A	Excessive transmit audio levels
B	Bit errors in the modem
C	Ground loops
D	Excessive numbers of retries

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	Transmission line length
C	Antenna height
D	The input power level

44. - E9B08

What is the far field of an antenna?

Select	Answer
A	The region where radiated power dissipates over a specified time period
B	The region of the ionosphere where radiated power is not refracted
C	The region where radiated field strengths are constant
D	The region where the shape of the antenna pattern is independent of distance

45. - E9C01

What is the radiation pattern of two 1/4-wavelength vertical antennas spaced 1/2-wavelength apart and fed 180 degrees out of phase?

Select	Answer
A	Omni-directional
B	Cardioid
C	A figure-8 broadside to the axis of the array
D	A figure-8 oriented along the axis of the array

46. - E9D07

What is an advantage of using top loading in a shortened HF vertical antenna?

Select	Answer
A	Higher losses
B	Greater structural strength
C	Improved radiation efficiency
D	Lower Q

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 stub match
C	The omega match
D	The gamma match

48. - E9F01

What is the velocity factor of a transmission line?

Select	Answer
A	The ratio of the characteristic impedance of the line to the terminating impedance
B	The velocity of the wave in the transmission line multiplied by the velocity of light in a vacuum
C	The index of shielding for coaxial cable
D	The velocity of the wave in the transmission line divided by the velocity of light in a vacuum

49. - E9G11

How are the wavelength scales on a Smith chart calibrated?

Select	Answer
A	In fractions of antenna electrical wavelength
B	In fractions of transmission line electrical frequency
C	In fractions of antenna electrical frequency
D	In fractions of transmission line electrical wavelength

50. - E9H08

What is the function of a sense antenna?

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

Figure E7-2

Figure E7-3