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

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1. - E0A04

When evaluating a site with multiple transmitters operating at the same time, the operators and licensees of which transmitters are responsible for mitigating over-exposure situations?

Select	Answer
A	Each transmitter that produces 5 percent or more of its MPE limit in areas where the total MPE limit is exceeded.
B	Only the most powerful transmitter
C	Only commercial transmitters
D	Each transmitter operating with a duty cycle greater than 50 percent

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 originating station
B	The control operator of the packet bulletin board 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. - E1B10

What frequencies are authorized to an amateur station operating under RACES rules?

Select	Answer
A	Specific segments in the amateur service MF, HF, VHF and UHF bands
B	Military Auxiliary Radio System (MARS) channels
C	Specific local government channels
D	All amateur service frequencies authorized to the control operator

4. - E1C08

What is the maximum permissible duration of a remotely controlled station's transmissions if its control link malfunctions?

Select	Answer
A	3 minutes
B	5 minutes
C	10 minutes
D	30 seconds

5. - E1D09

Which UHF amateur bands have frequencies authorized for space stations?

Select	Answer
A	70 cm only
B	33 cm and 13 cm
C	70 cm and 13 cm
D	70 cm and 33 cm

6. - E1E05

What is the minimum passing score on all amateur operator license examinations?

Select	Answer
A	Minimum passing score of 77%
B	Minimum passing score of 80%
C	Minimum passing score of 70%
D	Minimum passing score of 74%

7. - E1F10

Who may be the control operator of an auxiliary station?

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

8. - E2A01

What is the direction of an ascending pass for an amateur satellite?

Select	Answer
A	From north to south
B	From east to west
C	From west to east
D	From south to north

9. - E2B10

What aspect of an analog slow-scan television signal encodes the brightness of the picture?

Select	Answer
A	Sync frequency
B	Sync amplitude
C	Tone frequency
D	Tone amplitude

10. - E2C03

From which of the following bands is amateur radio contesting generally excluded?

Select	Answer
A	6 meters
B	2 meters
C	33 centimeters
D	30 meters

11. - E2D02

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

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

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. - E3A01

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

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

14. - E3B12

What is the primary characteristic of chordal hop propagation?

Select	Answer
A	Propagation across the geomagnetic equator
B	Signals reflected back toward the transmitting station
C	Successive ionospheric refractions without an intermediate reflection from the ground
D	Propagation away from the great circle bearing between stations

15. - E3C04

What does the value of Bz (B sub Z) represent?

Select	Answer
A	Duration of long-delayed echoes
B	Critical frequency for vertical transmissions
C	Direction and strength of the interplanetary magnetic field
D	Geomagnetic field stability

16. - E4A06

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

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

17. - E4B05

What three test loads are used to calibrate an RF vector network analyzer?

Select	Answer
A	Short circuit, open circuit, and 50 ohms
B	50 ohms through 1/8 wavelength, 1/4 wavelength, and 1/2 wavelength of coaxial cable
C	Short circuit, open circuit, and resonant circuit
D	50 ohms, 75 ohms, and 90 ohms

18. - E4C08

An SDR receiver is overloaded when input signals exceed what level?

Select	Answer
A	One-half the maximum sampling buffer size
B	The maximum count value of the analog-to-digital converter
C	The reference voltage of the analog-to-digital converter
D	One-half the maximum sample rate

19. - E4D02

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

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

20. - E4E06

What is one type of electrical interference that might be caused by a nearby personal computer?

Select	Answer
A	The appearance of unstable modulated or unmodulated signals at specific frequencies
B	A whining type noise that continually pulses off and on
C	A loud AC hum in the audio output of your station receiver
D	A clicking noise at intervals of a few seconds

21. - E5A09

How is the Q of an RLC parallel resonant circuit calculated?

Select	Answer
A	Reactance of either the inductance or capacitance divided by the resistance
B	Resistance divided by the reactance of either the inductance or capacitance
C	Reactance of the inductance multiplied by the reactance of the capacitance
D	Reactance of either the inductance or capacitance multiplied by the resistance

22. - E5B03

How is impedance in polar form converted to an equivalent admittance?

Select	Answer
A	Take the square root of the magnitude and add 180 degrees to the angle
B	Take the reciprocal of the angle and change the sign of the magnitude
C	Take the reciprocal of the magnitude and change the sign of the angle
D	Square the magnitude and subtract 90 degrees from the angle

23. - E5C09

When using rectangular coordinates to graph the impedance of a circuit, what do the axes represent?

Select	Answer
A	The X axis represents the reactive component and the Y axis represents the resistive component
B	The X axis represents the resistive component and the Y axis represents the reactive component
C	The X axis represents the magnitude and the Y axis represents the phase angle
D	The X axis represents the phase angle and the Y axis represents the magnitude

24. - E5D05

What is the power factor of an RL circuit having a 30-degree phase angle between the voltage and the current?

Select	Answer
A	0.577
B	0.5
C	0.866
D	1.73

25. - E6A06

What is the beta of a bipolar junction transistor?

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

26. - E6B07

What is the failure mechanism when a junction diode fails due to excessive current?

Select	Answer
A	Excessive junction temperature
B	Charge carrier depletion
C	Insufficient forward voltage
D	Excessive inverse voltage

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. - E6D10

What is a primary advantage of using a toroidal core instead of a solenoidal core in an inductor?

Select	Answer
A	Toroidal cores exhibit greater hysteresis
B	Toroidal cores have lower Q characteristics
C	Toroidal cores confine most of the magnetic field within the core material
D	Toroidal cores make it easier to couple the magnetic energy into other components

29. - E6E08

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

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

30. - E6F10

What is the most common type of photovoltaic cell used for electrical power generation?

Select	Answer
A	Silicon
B	Copper oxide
C	Cadmium Sulfide
D	Selenium

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

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

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 network with only three discrete parts
C	A matching network in which all components are isolated from ground
D	A Pi-network with an additional series inductor on the output

34. - E7D10

What is the primary reason that a high-frequency switching type high-voltage power supply can be both less expensive and lighter in weight than a conventional power supply?

Select	Answer
A	It uses a large power factor compensation capacitor to recover power from the unused portion of the AC cycle
B	The high frequency inverter design uses much smaller transformers and filter components for an equivalent power output
C	It uses a diode bridge rectifier for increased output
D	The inverter design does not require any output filtering

35. - E7E06

Why is de-emphasis commonly used in FM communications receivers?

Select	Answer
A	To reduce impulse noise reception
B	For compatibility with transmitters using phase modulation
C	For higher efficiency
D	To remove third-order distortion products

36. - E7F06

What is the minimum number of bits required for an analog-to-digital converter to sample a signal with a range of 1 volt at a resolution of 1 millivolt?

Select	Answer
A	10 bits
B	4 bits
C	8 bits
D	6 bits

37. - E7G04

What is meant by the "op-amp input offset voltage"?

Select	Answer
A	The difference between the output voltage of the op-amp and the input voltage required in the immediately following stage
B	The output voltage of the op-amp minus its input voltage
C	The differential input voltage needed to bring the open loop output voltage to zero
D	The potential between the amplifier input terminals of the op-amp in an open loop condition

38. - E7H15

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

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

39. - E8A03

What type of wave does a Fourier analysis show to be made up of sine waves of a given fundamental frequency plus all its harmonics?

Select	Answer
A	A cosine wave
B	A square wave
C	A sine wave
D	A sawtooth wave

40. - E8B05

What is the deviation ratio of an FM-phone signal having a maximum frequency swing of plus-or-minus 5 kHz when the maximum modulation frequency is 3 kHz?

Select	Answer
A	0.167
B	60
C	0.6
D	1.67

41. - E8C07

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

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

42. - E8D02

What spread spectrum communications technique uses a high-speed binary bit stream to shift the phase of an RF carrier?

Select	Answer
A	Phase compandored spread spectrum
B	Frequency hopping
C	Direct sequence
D	Binary phase-shift keying

43. - E9A06

What is the effective radiated power relative to a dipole of a repeater station with 200 watts transmitter power output, 4 dB feed line loss, 3.2 dB duplexer loss, 0.8 dB circulator loss, and 10 dBd antenna gain?

Select	Answer
A	2000 watts
B	317 watts
C	126 watts
D	300 watts

44. - E9B11

What is a disadvantage of decreasing the number of wire segments in an antenna model below 10 segments per half-wavelength?

Select	Answer
A	The resulting design will favor radiation of harmonic energy
B	The computed feed point impedance may be incorrect
C	The antenna will become mechanically unstable
D	Ground conductivity will not be accurately modeled

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 horizontal to vertical polarization
C	It changes the radiation pattern from bidirectional to unidirectional
D	It reflects the standing waves on the antenna elements back to the transmitter

46. - E9D10

What happens to feed-point impedance at the base of a fixed length HF mobile antenna when operated below its resonant frequency?

Select	Answer
A	The radiation resistance decreases and the capacitive reactance decreases
B	The radiation resistance increases and the capacitive reactance decreases
C	The radiation resistance decreases and the capacitive reactance increases
D	The radiation resistance increases and the capacitive reactance increases

47. - E9E01

What system matches a higher-impedance transmission line to a lower-impedance antenna by connecting the line to the driven element in two places spaced a fraction of a wavelength each side of element center?

Select	Answer
A	The omega matching system
B	The stub matching system
C	The gamma matching system
D	The delta matching system

48. - E9F10

What impedance does a 1/8-wavelength transmission line present to a generator when the line is shorted at the far end?

Select	Answer
A	A capacitive reactance
B	Zero
C	An inductive reactance
D	The same as the characteristic impedance of the line

49. - E9G10

What do the arcs on a Smith chart represent?

Select	Answer
A	Points with constant reactance
B	Frequency
C	SWR
D	Points with constant resistance

50. - E9H11

What feature of a cardioid pattern antenna makes it useful for direction finding?

Select	Answer
A	A very sharp peak
B	Broadband response
C	High radiation angle
D	A very sharp single null