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	Microwaves are ionizing radiation
C	Microwaves often travel long distances by ionospheric reflection
D	The extremely high frequency energy can damage the joints of antenna structures

2. - E1A06

Where must the carrier frequency of a CW signal be set to comply with FCC rules for 60 meter operation?

Select	Answer
A	On any frequency where the signal's sidebands are within the channel
B	At the lowest frequency of the channel
C	At the highest frequency of the channel
D	At the center frequency of the channel

3. - E1B05

What is the National Radio Quiet Zone?

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

4. - E1C12

On what portion of the 630 meter band are phone emissions permitted?

Select	Answer
A	The entire band
B	None
C	Only the bottom 3 kHz
D	Only the top 3 kHz

5. - E1D03

What is a space telecommand station?

Select	Answer
A	An amateur station that transmits communications to initiate, modify or terminate functions of a space station
B	An amateur station located in a satellite or a balloon more than 50 kilometers above the surface of the Earth
C	An amateur station located on the surface of the Earth for communication with other Earth stations by means of Earth satellites
D	An amateur station that receives telemetry from a satellite or balloon more than 50 kilometers above the surface of the Earth

6. - E1E02

Who does Part 97 task with maintaining the pools of questions for all U.S. amateur license examinations?

Select	Answer
A	The VEs
B	The ARRL
C	The VECs
D	The FCC

7. - E1F03

Under what circumstances may a dealer sell an external RF power amplifier capable of operation below 144 MHz if it has not been granted FCC certification?

Select	Answer
A	It was imported from a manufacturer in another country and was certificated by that country's government
B	The equipment dealer assembled it from a kit
C	It was imported from a manufacturer in a country that does not require certification of RF power amplifiers
D	It was purchased in used condition from an amateur operator and is sold to another amateur operator for use at that operator's station

8. - E2A06

What are Keplerian elements?

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

9. - E2B05

Which of the following describes the use of vestigial sideband in analog fast-scan TV transmissions?

Select	Answer
A	The vestigial sideband carries the audio information
B	Vestigial sideband reduces bandwidth while allowing for simple video detector circuitry
C	Vestigial sideband provides high frequency emphasis to sharpen the picture
D	The vestigial sideband contains chroma information

10. - E2C09

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

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

11. - E2D09

What type of modulation is used for JT65 contacts?

Select	Answer
A	Multi-tone AFSK
B	RTTY
C	IEEE 802.11
D	PSK

12. - E2E05

Which of these digital modes does not support keyboard-to-keyboard operation?

Select	Answer
A	PACTOR
B	RTTY
C	PSK31
D	MFSK

13. - E3A11

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

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

14. - E3B12

What is the primary characteristic of chordal hop propagation?

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

15. - E3C03

Which of the following signal paths is most likely to experience high levels of absorption when the A index or K index is elevated?

Select	Answer
A	Polar
B	Transequatorial
C	NVIS
D	Sporadic E

16. - E4A09

Which of the following is good practice when using an oscilloscope probe?

Select	Answer
A	Never use a high-impedance probe to measure a low-impedance circuit
B	Keep the signal ground connection of the probe as short as possible
C	Never use a DC-coupled probe to measure an AC circuit
D	All these choices are correct

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

18. - E4C14

What transmit frequency might generate an image response signal in a receiver tuned to 14.300 MHz and that uses a 455 kHz IF frequency?

Select	Answer
A	15.210 MHz
B	13.845 MHz
C	14.755 MHz
D	14.445 MHz

19. - E4D07

Which of the following reduces the likelihood of receiver desensitization?

Select	Answer
A	Raise the receiver IF frequency
B	Decrease the RF bandwidth of the receiver
C	Switch from fast AGC to slow AGC
D	Increase the receiver front end gain

20. - E4E06

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

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

21. - E5A14

What is the resonant frequency of an RLC circuit if R is 22 ohms, L is 50 microhenries and C is 40 picofarads?

Select	Answer
A	3.56 MHz
B	22.36 MHz
C	1.78 MHz
D	44.72 MHz

22. - E5B02

What letter is commonly used to represent susceptance?

Select	Answer
A	G
B	B
C	Y
D	X

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 inductive reactance
C	50 ohms resistance in series with 25 ohms inductive reactance
D	25 ohms resistance in series with 50 ohms capacitive reactance

24. - E5D09

What happens to reactive power in an AC circuit that has both ideal inductors and ideal capacitors?

Select	Answer
A	It is dissipated as kinetic energy in the circuit
B	It is dissipated in the formation of inductive and capacitive fields
C	It is dissipated as heat in the circuit
D	It is repeatedly exchanged between the associated magnetic and electric fields, but is not dissipated

25. - E6A10

In Figure E6-1, what is the schematic symbol for an N-channel dual-gate MOSFET?

Select	Answer
A	2
B	4
C	5
D	6

26. - E6B11

What is used to control the attenuation of RF signals by a PIN diode?

Select	Answer
A	Forward DC bias current
B	Capacitance of an RF coupling capacitor
C	A sub-harmonic pump signal
D	Reverse voltage larger than the RF signal

27. - E6C09

What is a Programmable Logic Device (PLD)?

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

28. - E6D11

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

Select	Answer
A	Ferrite
B	Ceramic
C	Powdered iron
D	Brass

29. - E6E10

What advantage does surface-mount technology offer at RF compared to using through-hole components?

Select	Answer
A	Smaller circuit area
B	Components have less parasitic inductance and capacitance
C	All these choices are correct
D	Shorter circuit-board traces

30. - E6F04

What is the photovoltaic effect?

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

31. - E7A01

Which circuit is bistable?

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

32. - E7B03

Which of the following components form the output of a class D amplifier circuit?

Select	Answer
A	A temperature compensating load resistor to improve linearity
B	A low-pass filter to remove switching signal components
C	A high-pass filter to compensate for low gain at low frequencies
D	A matched load resistor to prevent damage by switching transients

33. - E7C02

Which of the following is a property of a T-network with series capacitors and a parallel shunt inductor?

Select	Answer
A	It is a high-pass filter
B	It is a band-pass filter
C	It is a low-pass filter
D	It is a notch filter

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

35. - E7E06

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

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

36. - E7F01

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

Select	Answer
A	Incoming RF is converted to a control voltage for a voltage controlled oscillator
B	Software is converted from source code to object code during operation of the receiver
C	Incoming RF is digitized by an analog-to-digital converter without being mixed with a local oscillator signal
D	A switching mixer is used to generate I and Q signals directly from the RF input

37. - E7G04

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

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

38. - E7H09

What type of frequency synthesizer circuit uses a phase accumulator, lookup table, digital to analog converter, and a low-pass anti-alias filter?

Select	Answer
A	A hybrid synthesizer
B	A diode-switching matrix synthesizer
C	A direct digital synthesizer
D	A phase-locked loop synthesizer

39. - E8A07

What determines the PEP-to-average power ratio of a single-sideband phone signal?

Select	Answer
A	Speech characteristics
B	The frequency of the modulating signal
C	Amplifier gain
D	The degree of carrier suppression

40. - E8B10

What is frequency division multiplexing?

Select	Answer
A	Two or more information streams are merged into a baseband, which then modulates the transmitter
B	The transmitted signal jumps from band to band at a predetermined rate
C	The transmitted signal is divided into packets of information
D	Two or more information streams are merged into a digital combiner, which then pulse position modulates the transmitter

41. - E8C12

What factors affect the bandwidth of a transmitted CW signal?

Select	Answer
A	Modulation index and output power
B	IF bandwidth and Q
C	Keying speed and shape factor (rise and fall time)
D	All these choices are correct

42. - E8D09

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

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

43. - E9A13

What term describes station output, taking into account all gains and losses?

Select	Answer
A	Apparent power
B	Effective radiated power
C	Power factor
D	Half-power bandwidth

44. - E9B07

How does the total amount of radiation emitted by a directional gain antenna compare with the total amount of radiation emitted from a theoretical isotropic antenna, assuming each is driven by the same amount of power?

Select	Answer
A	The total amount of radiation from the directional antenna is increased by the gain of the antenna
B	The total amount of radiation from the directional antenna is stronger by its front-to-back ratio
C	They are the same
D	The radiation from the isotropic antenna is 2.15 dB stronger than that from the directional antenna

45. - E9C08

What is a folded dipole antenna?

Select	Answer
A	A half-wave dipole with an additional parallel wire connecting its two ends
B	A dipole one-quarter wavelength long
C	A type of ground-plane antenna
D	A dipole configured to provide forward gain

46. - E9D04

Why should an HF mobile antenna loading coil have a high ratio of reactance to resistance?

Select	Answer
A	To swamp out harmonics
B	To lower the radiation angle
C	To minimize losses
D	To minimize the Q

47. - E9E04

What is the purpose of the series capacitor in a gamma-type antenna matching network?

Select	Answer
A	To provide a rejection notch that prevents the radiation of harmonics
B	To provide DC isolation between the feed line and the antenna
C	To cancel the inductive reactance of the matching network
D	To transform the antenna impedance to a higher value

48. - E9F08

Which of the following is a significant difference between foam dielectric coaxial cable and solid dielectric cable, assuming all other parameters are the same?

Select	Answer
A	Foam dielectric has lower safe operating voltage limits
B	All these choices are correct
C	Foam dielectric has lower loss per unit of length
D	Foam dielectric has higher velocity factor

49. - E9G04

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

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

50. - E9H04

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

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

Figure E6-1