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	Any ordinary smoke detector can be used
C	By the odor
D	By the yellowish appearance of the gas

2. - E1A12

What special operating frequency restrictions are imposed on slow scan TV transmissions?

Select	Answer
A	They are not permitted above 54 MHz
B	They are restricted to phone band segments
C	They are restricted to 7.245 MHz, 14.245 MHz, 21.345 MHz, and 28.945 MHz
D	None; they are allowed on all amateur frequencies

3. - E1B01

Which of the following constitutes a spurious emission?

Select	Answer
A	An amateur station transmission made without the proper call sign identification
B	Any transmitted signal that unintentionally interferes with another licensed radio station
C	A signal transmitted to prevent its detection by any station other than the intended recipient
D	An emission outside the signal's necessary bandwidth that can be reduced or eliminated without affecting the information transmitted

4. - E1C12

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

Select	Answer
A	None
B	Only the top 3 kHz
C	The entire band
D	Only the bottom 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 on the surface of the Earth for communication with other Earth stations by means of Earth satellites
C	An amateur station that receives telemetry from a satellite or balloon more than 50 kilometers above the surface of the Earth
D	An amateur station located in a satellite or a balloon more than 50 kilometers above the surface of the Earth

6. - E1E10

What must the administering VEs do after the administration of a successful examination for an amateur operator license?

Select	Answer
A	They must collect and send the documents to the NCVEC for grading
B	They must submit the application document to the coordinating VEC according to the coordinating VEC instructions
C	They must collect and submit the documents to the coordinating VEC for grading
D	They must collect and send the documents to the FCC according to instructions

7. - E1F02

What privileges are authorized in the U.S. to persons holding an amateur service license granted by the government of Canada?

Select	Answer
A	Full privileges, up to and including those of the Amateur Extra Class license, on the 80, 40, 20, 15, and 10 meter bands
B	None, they must obtain a U.S. license
C	The operating terms and conditions of the Canadian amateur service license, not to exceed U.S. Amateur Extra Class license privileges
D	All privileges of the Amateur Extra Class license

8. - E2A01

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

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

9. - E2B12

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

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

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. - E2D02

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

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

12. - E2E01

Which of the following types of modulation is common for data emissions below 30 MHz?

Select	Answer
A	Spread spectrum
B	Pulse modulation
C	FSK
D	DTMF tones modulating an FM signal

13. - E3A13

Which of these emission modes is best for auroral propagation?

Select	Answer
A	FM
B	SSB
C	RTTY
D	CW

14. - E3B01

What is transequatorial propagation?

Select	Answer
A	Propagation between points at the same latitude
B	Propagation between points located on the magnetic equator
C	Propagation between two mid-latitude points at approximately the same distance north and south of the magnetic equator
D	Propagation between a point on the equator and its antipodal point

15. - E3C04

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

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

16. - E4A02

Which of the following parameters does a spectrum analyzer display on the vertical and horizontal axes?

Select	Answer
A	RF amplitude and time
B	SWR and time
C	RF amplitude and frequency
D	SWR and frequency

17. - E4B07

What do the subscripts of S parameters represent?

Select	Answer
A	The port or ports at which measurements are made
B	Relative quality of the data
C	The relative time between measurements
D	Frequency order of the measurements

18. - E4C15

What is reciprocal mixing?

Select	Answer
A	Two digital signals combining from alternate time slots
B	In-phase signals cancelling in a mixer resulting in loss of receiver sensitivity
C	Two out-of-band signals mixing to generate an in-band spurious signal
D	Local oscillator phase noise mixing with adjacent strong signals to create interference to desired signals

19. - E4D07

Which of the following reduces the likelihood of receiver desensitization?

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

20. - E4E05

How can radio frequency interference from an AC motor be suppressed?

Select	Answer
A	By installing a bypass capacitor in series with the motor leads
B	By using a ground-fault current interrupter in the circuit used to power the motor
C	By installing a high-pass filter in series with the motor's power leads
D	By installing a brute-force AC-line filter in series with the motor leads

21. - E5A03

What is the magnitude of the impedance of a series RLC circuit at resonance?

Select	Answer
A	High, as compared to the circuit resistance
B	Approximately equal to circuit resistance
C	Approximately equal to capacitive reactance
D	Approximately equal to inductive reactance

22. - E5B06

What is susceptance?

Select	Answer
A	The magnetic impedance of a circuit
B	The ratio of magnetic field to electric field
C	The imaginary part of admittance
D	A measure of the efficiency of a transformer

23. - E5C11

Which point in Figure E5-1 best represents the impedance of a series circuit consisting of a 300-ohm resistor and an 18-microhenry inductor at 3.505 MHz?

Select	Answer
A	Point 8
B	Point 3
C	Point 7
D	Point 1

24. - E5D06

In what direction is the magnetic field oriented about a conductor in relation to the direction of electron flow?

Select	Answer
A	In a circle around the conductor
B	In all directions; omni-directional
C	In the same direction as the current
D	In a direction opposite to the current

25. - E6A12

Why do many MOSFET devices have internally connected Zener diodes on the gates?

Select	Answer
A	To protect the substrate from excessive voltages
B	To provide a voltage reference for the correct amount of reverse-bias gate voltage
C	To keep the gate voltage within specifications and prevent the device from overheating
D	To reduce the chance of static damage to the gate

26. - E6B07

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

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

27. - E6C01

What is the function of hysteresis in a comparator?

Select	Answer
A	To prevent input noise from causing unstable output signals
B	To increase the sensitivity
C	To cause the output to change states continually
D	To allow the comparator to be used with AC input signals

28. - E6D02

What is the equivalent circuit of a quartz crystal?

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

29. - E6E06

What characteristics of the MMIC make it a popular choice for VHF through microwave circuits?

Select	Answer
A	Controlled gain, low noise figure, and constant input and output impedance over the specified frequency range
B	The ability to retrieve information from a single signal even in the presence of other strong signals
C	Nearly infinite gain, very high input impedance, and very low output impedance
D	Plate current that is controlled by a control grid

30. - E6F07

What is a solid-state relay?

Select	Answer
A	A relay using transistors to drive the relay coil
B	A mechanical relay that latches in the on or off state each time it is pulsed
C	A device that uses semiconductors to implement the functions of an electromechanical relay
D	A semiconductor passive delay line

31. - E7A04

How many flip-flops are required to divide a signal frequency by 4?

Select	Answer
A	4
B	1
C	2
D	8

32. - E7B11

In Figure E7-1, what is the purpose of R3?

Select	Answer
A	Emitter bypass
B	Self bias
C	Output load resistor
D	Fixed bias

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

34. - E7D12

What is the dropout voltage of an analog voltage regulator?

Select	Answer
A	Maximum that the output voltage may decrease at rated load
B	Maximum output voltage drops when the input voltage is varied over its specified range
C	Minimum input-to-output voltage required to maintain regulation
D	Minimum input voltage for rated power dissipation

35. - E7E09

What occurs when an excessive amount of signal energy reaches a mixer circuit?

Select	Answer
A	A beat frequency is generated
B	Mixer blanking occurs
C	Spurious mixer products are generated
D	Automatic limiting occurs

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	4 bits
B	8 bits
C	6 bits
D	10 bits

37. - E7G09

What will be the output voltage of the circuit shown in Figure E7-3 if R1 is 1000 ohms, RF is 10,000 ohms, and 0.23 volts DC is applied to the input?

Select	Answer
A	2.3 volts
B	-2.3 volts
C	0.23 volts
D	-0.23 volts

38. - E7H08

Which of the following components can be used to reduce thermal drift in crystal oscillators?

Select	Answer
A	Wirewound resistors
B	NP0 capacitors
C	Non-inductive resistors
D	Toroidal inductors

39. - E8A04

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

Select	Answer
A	A small amount of noise added to the input signal to allow more precise representation of a signal over time
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	An error caused by irregular quantization step size

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

41. - E8C08

How does ARQ accomplish error correction?

Select	Answer
A	Special polynomial codes provide automatic correction
B	If errors are detected, a retransmission is requested
C	If errors are detected, redundant data is substituted
D	Special binary codes provide automatic correction

42. - E8D11

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

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

43. - E9A05

What is included in the total resistance of an antenna system?

Select	Answer
A	Transmission-line resistance plus radiation resistance
B	Radiation resistance plus transmission resistance
C	Radiation resistance plus space impedance
D	Radiation resistance plus loss resistance

44. - E9B02

In the antenna radiation pattern shown in Figure E9-1, what is the front-to-back ratio?

Select	Answer
A	18 dB
B	36 dB
C	24 dB
D	14 dB

45. - E9C10

Which of the following describes a Zepp antenna?

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

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 minimize the Q
C	To minimize losses
D	To lower the radiation angle

47. - E9E08

What is a use for a Wilkinson divider?

Select	Answer
A	It is used to divide power equally between two 50-ohm loads while maintaining 50-ohm input impedance
B	It is used to feed low-impedance loads from a high-impedance source
C	It is used to feed high-impedance antennas from a low-impedance source
D	It divides the operating frequency of a transmitter signal so it can be used on a lower frequency band

48. - E9F04

What impedance does a 1/2-wavelength transmission line present to a generator when the line is shorted at the far end?

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

49. - E9G01

Which of the following can be calculated using a Smith chart?

Select	Answer
A	Impedance along transmission lines
B	Antenna radiation pattern
C	Radio propagation
D	Radiation resistance

50. - E9H11

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

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

Figure E5-1

Figure E7-1

Figure E7-3

Figure E9-1