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

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1. - E0A07

How may dangerous levels of carbon monoxide from an emergency generator be detected?

Select	Answer
A	Only with a carbon monoxide detector
B	By the yellowish appearance of the gas
C	By the odor
D	Any ordinary smoke detector can be used

2. - E1A04

With your transceiver displaying the carrier frequency of phone signals, you hear a DX station calling CQ on 3.601 MHz LSB. Is it legal to return the call using lower sideband on the same frequency?

Select	Answer
A	Yes, because the DX station initiated the contact
B	No, the sideband will extend beyond the edge of the phone band segment
C	Yes, because the displayed frequency is within the 75 meter phone band segment
D	No, U.S. stations are not permitted to use phone emissions below 3.610 MHz

3. - E1B02

Which of the following is an acceptable bandwidth for Digital Radio Mondiale (DRM) based voice or SSTV digital transmissions made on the HF amateur bands?

Select	Answer
A	10 kHz
B	20 kHz
C	3 kHz
D	15 kHz

4. - E1C03

How do the control operator responsibilities of a station under automatic control differ from one under local control?

Select	Answer
A	Under automatic control there is no control operator
B	Under local control there is no control operator
C	Under automatic control the control operator is not required to be present at the control point
D	Under local control a control operator is not required to be present at a control point

5. - E1D02

Which of the following may transmit special codes intended to obscure the meaning of messages?

Select	Answer
A	Auxiliary relay links carrying repeater audio
B	Telecommand signals from a space telecommand station
C	Data containing personal information
D	Binary control characters

6. - E1E01

For which types of out-of-pocket expenses do the Part 97 rules state that VEs and VECs may be reimbursed?

Select	Answer
A	Teaching an amateur operator license examination preparation course
B	No expenses are authorized for reimbursement
C	Providing amateur operator license examination preparation training materials
D	Preparing, processing, administering, and coordinating an examination for an amateur radio operator license

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	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	The equipment dealer assembled it from a kit
D	It was imported from a manufacturer in a country that does not require certification of RF power amplifiers

8. - E2A09

What do the terms L band and S band specify regarding satellite communications?

Select	Answer
A	The 2 meter and 70 centimeter bands
B	The 23 centimeter and 13 centimeter bands
C	Which sideband to use
D	FM and Digital Store-and-Forward systems

9. - E2B07

What is the name of the signal component that carries color information in NTSC video?

Select	Answer
A	Spectral intensity
B	Luminance
C	Hue
D	Chroma

10. - E2C04

Which of the following frequencies are sometimes used for amateur radio mesh networks?

Select	Answer
A	Cable TV channels 41 through 43
B	HF frequencies where digital communications are permitted
C	Frequencies shared with various unlicensed wireless data services
D	The 60 meter band channel centered on 5373 kHz

11. - E2D08

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

Select	Answer
A	Connect
B	Disconnect
C	Unnumbered Information
D	Acknowledgement

12. - E2E02

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

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

13. - E3A13

Which of these emission modes is best for auroral propagation?

Select	Answer
A	CW
B	SSB
C	FM
D	RTTY

14. - E3B04

What is meant by the terms "extraordinary" and "ordinary" waves?

Select	Answer
A	Refracted rays and reflected waves
B	Independent waves created in the ionosphere that are elliptically polarized
C	Long-path and short-path waves
D	Extraordinary waves describe rare long-skip propagation compared to ordinary waves, which travel shorter distances

15. - E3C11

What does VOACAP software model?

Select	Answer
A	AC voltage and impedance
B	HF propagation
C	AC current and impedance
D	VHF radio propagation

16. - E4A01

Which of the following limits the highest frequency signal that can be accurately displayed on a digital oscilloscope?

Select	Answer
A	Sampling rate of the analog-to-digital converter
B	All these choices are correct
C	Q of the circuit
D	Amount of memory

17. - E4B11

Which of the following can be measured with a vector network analyzer?

Select	Answer
A	Input impedance
B	All these choices are correct
C	Output impedance
D	Reflection coefficient

18. - E4C11

Why can an attenuator be used to reduce receiver overload on the lower frequency HF bands with little or no impact on signal-to-noise ratio?

Select	Answer
A	Atmospheric noise is generally greater than internally generated noise even after attenuation
B	The attenuator has a low-pass filter to increase the strength of lower frequency signals
C	Signals are attenuated separately from the noise
D	The attenuator has a noise filter to suppress interference

19. - E4D02

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

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

20. - E4E09

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

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

21. - E5A05

What is the result of increasing the Q of an impedance-matching circuit?

Select	Answer
A	It has no effect on impedance matching
B	Matching range is increased
C	Matching bandwidth is decreased
D	Matching bandwidth is increased

22. - E5B02

What letter is commonly used to represent susceptance?

Select	Answer
A	B
B	X
C	G
D	Y

23. - E5C04

What coordinate system is often used to display the resistive, inductive, and/or capacitive reactance components of impedance?

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

24. - E5D12

How many watts are consumed in a circuit having a power factor of 0.2 if the input is 100 VAC at 4 amperes?

Select	Answer
A	2000 watts
B	400 watts
C	80 watts
D	50 watts

25. - E6A05

How does DC input impedance at the gate of a field-effect transistor compare with the DC input impedance of a bipolar transistor?

Select	Answer
A	An FET has lower input impedance
B	They are both high impedance
C	An FET has higher input impedance
D	They are both low impedance

26. - E6B06

Which of the following is a common use of a Schottky diode?

Select	Answer
A	As a rectifier in high current power supplies
B	As a VHF/UHF mixer or detector
C	As a constant voltage reference in a power supply
D	As a variable capacitance in an automatic frequency control circuit

27. - E6C05

What is an advantage of CMOS logic devices over TTL devices?

Select	Answer
A	Lower power consumption
B	Lower distortion
C	Differential output capability
D	Immune to damage from static discharge

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

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 noise figures
C	Lower transconductance
D	Higher electron mobility

30. - E6F08

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

Select	Answer
A	Optoisolators eliminate the effects of reflected light in the control circuit
B	Optoisolators provide a very high degree of electrical isolation between a control circuit and the circuit being switched
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. - E7A09

What logical operation is performed by an exclusive NOR gate?

Select	Answer
A	It produces logic 1 at its output if only one input is logic 1
B	It produces logic 1 at its output only if all inputs are logic 1
C	It produces logic 0 at its output if only one input is logic 1
D	It produces logic 0 at its output only if all inputs are logic 0

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

33. - E7C10

Which of the following filters would be the best choice for use in a 2 meter band repeater duplexer?

Select	Answer
A	A DSP filter
B	An L-C filter
C	A cavity filter
D	A crystal filter

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 shunt regulator
C	A shunt current source
D	A series regulator

35. - E7E02

What is the function of a reactance modulator?

Select	Answer
A	To produce PM or FM signals by using an electrically variable inductance or capacitance
B	To produce AM signals by using an electrically variable resistance
C	To produce AM signals by using an electrically variable inductance or capacitance
D	To produce PM signals by using an electrically variable resistance

36. - E7F12

Which of the following is an advantage of a Finite Impulse Response (FIR) filter vs an Infinite Impulse Response (IIR) digital filter?

Select	Answer
A	FIR filters can delay all frequency components of the signal by the same amount
B	FIR filters are easier to implement for a given set of passband rolloff requirements
C	All these choices are correct
D	FIR filters can respond faster to impulses

37. - E7G12

What is an operational amplifier?

Select	Answer
A	An amplifier used to increase the average output of frequency modulated amateur signals to the legal limit
B	A RF amplifier used in the UHF and microwave regions
C	A high-gain, direct-coupled differential amplifier with very high input impedance and very low output impedance
D	A digital audio amplifier whose characteristics are determined by components external to the amplifier

38. - E7H01

What are three oscillator circuits used in amateur radio equipment?

Select	Answer
A	Taft, Pierce and negative feedback
B	Taft, Hartley and Pierce
C	Colpitts, Hartley and Pierce
D	Pierce, Fenner and Beane

39. - E8A06

What is the approximate ratio of PEP-to-average power in a typical single-sideband phone signal?

Select	Answer
A	2.5 to 1
B	25 to 1
C	1 to 1
D	100 to 1

40. - E8B07

Orthogonal Frequency Division Multiplexing is a technique used for which type of amateur communication?

Select	Answer
A	EME
B	Extremely low-power contacts
C	OFDM signals are not allowed on amateur bands
D	High-speed digital modes

41. - E8C01

How is Forward Error Correction implemented?

Select	Answer
A	By the receiving station repeating each block of three data characters
B	By transmitting extra data that may be used to detect and correct transmission errors
C	By varying the frequency shift of the transmitted signal according to a predefined algorithm
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	Bit errors in the modem
C	Excessive numbers of retries
D	Ground loops

43. - E9A13

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

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

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 where radiated field strengths are constant
C	The region where the shape of the antenna pattern is independent of distance
D	The region of the ionosphere where radiated power is not refracted

45. - E9C09

Which of the following describes a G5RV antenna?

Select	Answer
A	A phased array antenna consisting of multiple loops
B	A wide band dipole using shorted coaxial cable for the radiating elements and fed with a�4:1 balun
C	A multi-band dipole antenna fed with coax and a balun through a selected length of open wire transmission line
D	A multi-band trap antenna

46. - E9D01

How much does the gain of an ideal parabolic dish antenna change when the operating frequency is doubled?

Select	Answer
A	2 dB
B	4 dB
C	6 dB
D	3 dB

47. - E9E06

Which of these feed line impedances would be suitable for constructing a quarter-wave Q-section for matching a 100-ohm loop to 50-ohm feed line?

Select	Answer
A	75 ohms
B	50 ohms
C	62 ohms
D	450 ohms

48. - E9F12

What impedance does a 1/4-wavelength transmission line present to a generator when the line is open at the far end?

Select	Answer
A	The same as the characteristic impedance of the line
B	Very low impedance
C	The same as the input impedance to the generator
D	Very high impedance

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. - E9H07

Why is RF attenuation used when direction-finding?

Select	Answer
A	To prevent receiver overload which reduces pattern nulls
B	To narrow the receiver bandwidth
C	To increase receiver sensitivity
D	To compensate for isotropic directivity and the antenna effect of feed lines