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

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

3. - E1B06

Which of the following additional rules apply if you are installing an amateur station antenna at a site at or near a public use airport?

Select	Answer
A	You may have to notify the Federal Aviation Administration and register it with the FCC as required by Part 17 of the FCC rules
B	You must submit engineering drawings to the FAA
C	You must file an Environmental Impact Statement with the EPA before construction begins
D	You must obtain a construction permit from the airport zoning authority

4. - E1C07

At what level below a signal's mean power level is its bandwidth determined according to FCC rules?

Select	Answer
A	26 dB
B	3 dB
C	23 dB
D	6 dB

5. - E1D08

Which VHF amateur bands have frequencies authorized for space stations?

Select	Answer
A	2 meters
B	6 meters, 2 meters, and 1.25 meters
C	2 meters and 1.25 meters
D	6 meters and 2 meters

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. - E1F05

Amateur stations may not transmit in which of the following frequency segments if they are located in the contiguous 48 states and north of Line A?

Select	Answer
A	53 MHz - 54 MHz
B	420 MHz - 430 MHz
C	222 MHz - 223 MHz
D	440 MHz - 450 MHz

8. - E2A11

What type of antenna can be used to minimize the effects of spin modulation and Faraday rotation?

Select	Answer
A	An isotropic antenna
B	A log-periodic dipole array
C	A circularly polarized antenna
D	A linearly polarized antenna

9. - E2B06

What is vestigial sideband modulation?

Select	Answer
A	A type of modulation in which one sideband is inverted
B	Amplitude modulation in which one complete sideband and a portion of the other are transmitted
C	Narrow-band FM modulation achieved by filtering one sideband from the audio before frequency modulating the carrier
D	Spread spectrum modulation achieved by applying FM modulation following single sideband amplitude modulation

10. - E2C12

What technique do individual nodes use to form a mesh network?

Select	Answer
A	Forward error correction and Viterbi codes
B	Acting as store-and-forward digipeaters
C	Discovery and link establishment protocols
D	Custom code plugs for the local trunking systems

11. - E2D08

What type of packet frame is used to transmit APRS beacon data?

Select	Answer
A	Unnumbered Information
B	Connect
C	Disconnect
D	Acknowledgement

12. - E2E02

What do the letters FEC mean as they relate to digital operation?

Select	Answer
A	Forward Error Correction
B	Final Error Correction
C	First Error Correction
D	Fatal Error Correction

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 produced by a loop antenna
C	Waves with a rotating electric field
D	Waves that circle the Earth

14. - E3B02

What is the approximate maximum range for signals using transequatorial propagation?

Select	Answer
A	1000 miles
B	2500 miles
C	7500 miles
D	5000 miles

15. - E3C09

How does the intensity of an X3 flare compare to that of an X2 flare?

Select	Answer
A	Four times as great
B	Twice as great
C	50 percent greater
D	10 percent greater

16. - E4A08

Which of the following measures SWR?

Select	Answer
A	An ohmmeter
B	A spectrum analyzer
C	A Q meter
D	An antenna analyzer

17. - E4B04

Which S parameter represents input port return loss or reflection coefficient (equivalent to VSWR)?

Select	Answer
A	S22
B	S11
C	S12
D	S21

18. - E4C01

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

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

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	Adjacent channel interference
B	Intermodulation
C	Amplifier desensitization
D	Neutralization

20. - E4E07

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

Select	Answer
A	Use of braided shielding material
B	Low inductance ground connections at both ends of the shield
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. - 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	22.36 MHz
B	44.72 MHz
C	1.78 MHz
D	3.56 MHz

22. - E5B10

What is the relationship between the AC current through an inductor and the voltage across an inductor?

Select	Answer
A	Voltage and current are 180 degrees out of phase
B	Current leads voltage by 90 degrees
C	Voltage leads current by 90 degrees
D	Voltage and current are in phase

23. - E5C08

What coordinate system is often used to display the phase angle of a circuit containing resistance, inductive and/or capacitive reactance?

Select	Answer
A	Elliptical coordinates
B	Maidenhead grid
C	Faraday grid
D	Polar coordinates

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	0.5
B	1.73
C	0.577
D	0.866

25. - E6A03

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

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

26. - E6B01

What is the most useful characteristic of a Zener diode?

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

27. - E6C11

In Figure E6-3, what is the schematic symbol for the NOT operation (inverter)?

Select	Answer
A	6
B	5
C	4
D	2

28. - E6D02

What is the equivalent circuit of a quartz crystal?

Select	Answer
A	Motional capacitance, motional inductance, and loss resistance in series, all in parallel with a shunt capacitor representing electrode and stray capacitance
B	Motional inductance and loss resistance in series, paralleled with motional capacitance and a capacitor representing electrode and stray capacitance
C	Motional capacitance, motional inductance, loss resistance, and a capacitor representing electrode and stray capacitance all in parallel
D	Motional capacitance, motional inductance, loss resistance, and a capacitor representing electrode and stray capacitance all in series

29. - E6E01

Why is gallium arsenide (GaAs) useful for semiconductor devices operating at UHF and higher frequencies?

Select	Answer
A	Lower junction voltage drop
B	Higher electron mobility
C	Higher noise figures
D	Lower transconductance

30. - E6F08

Why are optoisolators often used in conjunction with solid-state circuits when switching 120 VAC?

Select	Answer
A	Optoisolators provide a very high degree of electrical isolation between a control circuit and the circuit being switched
B	Optoisolators eliminate the effects of reflected light in the control circuit
C	Optoisolators provide a low impedance link between a control circuit and a power circuit
D	Optoisolators provide impedance matching between the control circuit and power circuit

31. - E7A11

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

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

32. - E7B17

Why are odd-order rather than even-order intermodulation distortion products of concern in linear power amplifiers?

Select	Answer
A	Because they are relatively close in frequency to the desired signal
B	Because they invert the sidebands causing distortion
C	Because they are relatively far in frequency from the desired signal
D	Because they maintain the sidebands, thus causing multiple duplicate signals

33. - E7C12

What is one advantage of a Pi-matching network over an L-matching network consisting of a single inductor and a single capacitor?

Select	Answer
A	Pi-networks provide balanced input and output
B	The Q of Pi-networks can be controlled
C	Pi-networks are more stable
D	L-networks cannot perform impedance transformation

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 series regulator
C	A shunt regulator
D	A shunt current source

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. - E7F01

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

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

37. - E7G01

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

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

38. - E7H06

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

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

39. - E8A04

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

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

40. - E8B08

What describes Orthogonal Frequency Division Multiplexing?

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

41. - E8C01

How is Forward Error Correction implemented?

Select	Answer
A	By varying the frequency shift of the transmitted signal according to a predefined algorithm
B	By the receiving station repeating each block of three data characters
C	By transmitting extra data that may be used to detect and correct transmission errors
D	By transmitting a special algorithm to the receiving station along with the data characters

42. - E8D07

What is a common cause of overmodulation of AFSK signals?

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

43. - E9A04

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

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

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	14 dB
C	12 dB
D	24 dB

45. - E9C06

What is the effect of adding a terminating resistor to a rhombic antenna?

Select	Answer
A	It changes the radiation pattern from bidirectional to unidirectional
B	It changes the radiation pattern from horizontal to vertical polarization
C	It reflects the standing waves on the antenna elements back to the transmitter
D	It decreases the ground loss

46. - E9D03

Where should a high Q loading coil be placed to minimize losses in a shortened vertical antenna?

Select	Answer
A	At a voltage node
B	Near the center of the vertical radiator
C	As close to the transmitter as possible
D	As low as possible on the vertical radiator

47. - E9E11

What is the primary purpose of phasing lines when used with an antenna having multiple driven elements?

Select	Answer
A	It ensures that each driven element operates in concert with the others to create the desired antenna pattern
B	It allows single-band antennas to operate on other bands
C	It creates a low-angle radiation pattern
D	It prevents reflected power from traveling back down the feed line and causing harmonic radiation from the transmitter

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

49. - E9G09

What third family of circles is often added to a Smith chart during the process of solving problems?

Select	Answer
A	Standing wave ratio circles
B	Coaxial-length circles
C	Radiation-pattern circles
D	Antenna-length circles

50. - E9H02

Which is generally true for low band (160 meter and 80 meter) receiving antennas?

Select	Answer
A	Atmospheric noise is so high that gain over a dipole is not important
B	They must be erected at least 1/2 wavelength above the ground to attain good directivity
C	Low loss coax transmission line is essential for good performance
D	All these choices are correct

Figure E6-3

Figure E9-1