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

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1. - E0A01

What is the primary function of an external earth connection or ground rod?

Select	Answer
A	Lightning protection
B	Reduce RFI to telephones and home entertainment systems
C	Reduce RF current flow between pieces of equipment
D	Reduce received noise

2. - E1A02

When using a transceiver that displays the carrier frequency of phone signals, which of the following displayed frequencies represents the lowest frequency at which a properly adjusted LSB emission will be totally within the band?

Select	Answer
A	1 kHz above the lower band edge
B	The exact lower band edge
C	300 Hz above the lower band edge
D	3 kHz above the lower band edge

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 surrounding the National Radio Astronomy Observatory
C	An area in Florida surrounding Cape Canaveral
D	An area in New Mexico surrounding the White Sands Test Area

4. - E1C02

Which of the following types of communications may be transmitted to amateur stations in foreign countries?

Select	Answer
A	Communications incidental to the purpose of the amateur service and remarks of a personal nature
B	Messages intended for users of the maritime satellite service
C	Business-related messages for non-profit organizations
D	All these choices are correct

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	All these choices are correct
C	The station's six-character Maidenhead grid locator
D	Call sign

6. - E1E09

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

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

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

8. - E2A04

What is meant by the term mode? as applied to an amateur radio satellite?

Select	Answer
A	The satellite's orientation with respect to the Earth
B	Whether the satellite is in a low earth or geostationary orbit
C	The satellite's uplink and downlink frequency bands
D	Whether the satellite is in a polar or equatorial orbit

9. - E2B12

What signals SSTV receiving software to begin a new picture line?

Select	Answer
A	Specific tone amplitudes
B	Elapsed time
C	A two-tone signal
D	Specific tone frequencies

10. - E2C05

What is the function of a DX QSL Manager?

Select	Answer
A	To relay calls to and from a DX station
B	To run a net to allow many stations to contact a rare DX station
C	To allocate frequencies for DXpeditions
D	To handle the receiving and sending of confirmation cards for a DX station

11. - E2D01

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

Select	Answer
A	WSPR
B	APRS
C	MSK144
D	Hellschreiber

12. - E2E07

Which of the following is a possible reason that attempts to initiate contact with a digital station on a clear frequency are unsuccessful?

Select	Answer
A	Your transmit frequency is incorrect
B	All these choices are correct
C	Another station you are unable to hear is using the frequency
D	The protocol version you are using is not supported by the digital station

13. - E3A14

What is meant by circularly polarized electromagnetic waves?

Select	Answer
A	Waves with an electric field bent into a circular shape
B	Waves that circle the Earth
C	Waves produced by a loop antenna
D	Waves with a rotating electric field

14. - E3B06

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

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

15. - E3C12

How does the maximum range of ground-wave propagation change when the signal frequency is increased?

Select	Answer
A	It peaks at roughly 14 MHz
B	It stays the same
C	It decreases
D	It increases

16. - E4A05

What is the purpose of the prescaler function on a frequency counter?

Select	Answer
A	It prevents oscillation in a low-frequency counter circuit
B	It amplifies low-level signals for more accurate counting
C	It divides a higher frequency signal so a low-frequency counter can display the input frequency
D	It multiplies a higher frequency signal so a low-frequency counter can display the operating frequency

17. - E4B03

Which S parameter is equivalent to forward gain?

Select	Answer
A	S12
B	S21
C	S22
D	S11

18. - E4C07

What does the MDS of a receiver represent?

Select	Answer
A	The maximum detectable spectrum
B	The meter display sensitivity
C	The multiplex distortion stability
D	The minimum discernible signal

19. - E4D08

What causes intermodulation in an electronic circuit?

Select	Answer
A	Nonlinear circuits or devices
B	Positive feedback
C	Lack of neutralization
D	Too little gain

20. - E4E09

What undesirable effect can occur when using an IF noise blanker?

Select	Answer
A	Received audio in the speech range might have an echo effect
B	The audio frequency bandwidth of the received signal might be compressed
C	FM signals can no longer be demodulated
D	Nearby signals may appear to be excessively wide even if they meet emission standards

21. - E5A06

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

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

22. - E5B03

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

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

23. - E5C05

What is the name of the diagram used to show the phase relationship between impedances at a given frequency?

Select	Answer
A	Far field diagram
B	Phasor diagram
C	Near field diagram
D	Venn diagram

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

25. - E6A01

In what application is gallium arsenide used as a semiconductor material?

Select	Answer
A	In very low-frequency RF circuits
B	In high-current rectifier circuits
C	In high-power audio circuits
D	In microwave circuits

26. - E6B01

What is the most useful characteristic of a Zener diode?

Select	Answer
A	A constant current drop under conditions of varying voltage
B	An internal capacitance that varies with the applied voltage
C	A negative resistance region
D	A constant voltage drop under conditions of varying current

27. - E6C06

Why do CMOS digital integrated circuits have high immunity to noise on the input signal or power supply?

Select	Answer
A	Bandwidth is very limited
B	The input switching threshold is about one-half the power supply voltage
C	The input switching threshold is about two times the power supply voltage
D	Large bypass capacitance is inherent

28. - E6D06

What core material property determines the inductance of an inductor?

Select	Answer
A	Permeability
B	Resistance
C	Thermal impedance
D	Reactivity

29. - E6E10

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

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

30. - E6F01

What absorbs the energy from light falling on a photovoltaic cell?

Select	Answer
A	Photons
B	Protons
C	Electrons
D	Holes

31. - E7A11

What type of logic defines "1" as a high voltage?

Select	Answer
A	Assertive Logic
B	Negative logic
C	Reverse Logic
D	Positive Logic

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	Tune both the input and output for maximum power
C	Tune the stage for maximum SWR
D	Install parasitic suppressors and/or neutralize the stage

33. - E7C06

What are the distinguishing features of an elliptical filter?

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

34. - E7D07

What is the purpose of C2 in the circuit shown in Figure E7-2?

Select	Answer
A	To self-resonate at the hum frequency
B	It is a brute force filter for the output
C	It bypasses rectifier output ripple around D1
D	To provide fixed DC bias for Q1

35. - E7E03

What is a frequency discriminator stage in a FM receiver?

Select	Answer
A	An automatic band-switching circuit
B	A circuit for filtering two closely adjacent signals
C	A circuit for detecting FM signals
D	An FM generator circuit

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

37. - E7G04

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

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

38. - E7H11

What are the major spectral impurity components of direct digital synthesizers?

Select	Answer
A	Nyquist limit noise
B	Digital conversion noise
C	Broadband noise
D	Spurious signals at discrete frequencies

39. - E8A04

What is "dither" with respect to analog-to-digital converters?

Select	Answer
A	An abnormal condition where the converter cannot settle on a value to represent the signal
B	A method of decimation by randomly skipping samples
C	An error caused by irregular quantization step size
D	A small amount of noise added to the input signal to allow more precise representation of a signal over time

40. - E8B09

What is deviation ratio?

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

41. - E8C03

Why should phase-shifting of a PSK signal be done at the zero crossing of the RF signal?

Select	Answer
A	To simplify modulation
B	All these choices are correct
C	To improve carrier suppression
D	To minimize bandwidth

42. - E8D11

What is one advantage of using ASCII code for data communications?

Select	Answer
A	It uses one character as a shift code to send numeric and special characters
B	It includes built-in error correction features
C	It contains fewer information bits per character than any other code
D	It is possible to transmit both upper and lower case text

43. - E9A09

What is antenna efficiency?

Select	Answer
A	Total resistance divided by radiation resistance
B	Effective radiated power divided by transmitter output
C	Radiation resistance divided by total resistance
D	Radiation resistance divided by transmission resistance

44. - E9B05

What type of antenna pattern is shown in Figure E9-2?

Select	Answer
A	Elevation
B	Radiation resistance
C	Polarization
D	Azimuth

45. - E9C10

Which of the following describes a Zepp antenna?

Select	Answer
A	A dipole constructed from zip cord
B	An end-fed dipole antenna
C	An omni-directional antenna commonly used for satellite communications
D	A vertical array capable of quickly changing the direction of maximum radiation by changing phasing lines

46. - E9D11

Which of the following conductors would be best for minimizing losses in a station's RF ground system?

Select	Answer
A	Wide flat copper strap
B	Solid wire
C	Resistive wire, such as spark plug wire
D	Stranded wire

47. - E9E10

Which of these choices is an effective way to match an antenna with a 100-ohm feed point impedance to a 50-ohm coaxial cable feed line?

Select	Answer
A	Insert a 1/2 wavelength piece of 300-ohm twinlead in series between the antenna terminals and the 50-ohm feed cable
B	Insert a 1/4-wavelength piece of 75-ohm coaxial cable transmission line in series between the antenna terminals and the 50-ohm feed cable
C	Connect a 1/2 wavelength shorted stub of 75-ohm cable in parallel with the 50-ohm cable where it attaches to the antenna
D	Connect a 1/4-wavelength open stub of 300-ohm twinlead in parallel with the coaxial feed line where it connects to the antenna

48. - E9F03

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

Select	Answer
A	The characteristic impedance is higher in a parallel feed line
B	Electrical signals move more slowly in a coaxial cable than in air
C	The surge impedance is higher in a parallel feed line
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	Resistance and reactance
C	Resistance and voltage
D	Voltage and impedance

50. - E9H10

How can the output voltage of a multiple-turn receiving loop antenna be increased?

Select	Answer
A	By winding adjacent turns in opposing directions
B	By reducing the permeability of the loop shield
C	By increasing the number of turns and/or the area
D	By utilizing high impedance wire for the coupling loop

Figure E7-2

Figure E9-2