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

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1. - E0A09

Which insulating material commonly used as a thermal conductor for some types of electronic devices is extremely toxic if broken or crushed and the particles are accidentally inhaled?

Select	Answer
A	Mica
B	Zinc oxide
C	Beryllium Oxide
D	Uranium Hexafluoride

2. - E1A08

If a station in a message forwarding system inadvertently forwards a message that is in violation of FCC rules, who is primarily accountable for the rules violation?

Select	Answer
A	The control operators of all the stations in the system not authenticating the source from which they accept communications
B	The control operator of the packet bulletin board station
C	The control operator of the originating station
D	The control operators of all the stations in the system

3. - E1B07

To what type of regulations does PRB-1 apply?

Select	Answer
A	Use of wireless devices in vehicles
B	FAA tower height limits
C	State and local zoning
D	Homeowners associations

4. - E1C12

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

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

5. - E1D10

Which amateur stations are eligible to be telecommand stations of space stations (subject to the privileges of the class of operator license held by the control operator of the station)?

Select	Answer
A	Any amateur station so designated by the ITU
B	Any amateur station so designated by the space station licensee
C	All these choices are correct
D	Any amateur station designated by NASA

6. - E1E07

What should a VE do if a candidate fails to comply with the examiner's instructions during an amateur operator license examination?

Select	Answer
A	Warn the candidate that continued failure to comply will result in termination of the examination
B	Allow the candidate to complete the examination, but invalidate the results
C	Immediately terminate everyone's examination and close the session
D	Immediately terminate the candidate's examination

7. - E1F04

Which of the following geographic descriptions approximately describes "Line A"?

Select	Answer
A	A line roughly parallel to and south of the border between the U.S. and Canada
B	A line roughly parallel to and east of the U.S. Pacific coastline
C	A line roughly parallel to and west of the U.S. Atlantic coastline
D	A line roughly parallel to and north of the border between the U.S. and Mexico

8. - E2A01

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

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

9. - E2B04

How is color information sent in analog SSTV?

Select	Answer
A	Color information is sent on a 2.8 kHz subcarrier
B	Color lines are sent sequentially
C	Color is amplitude modulated on the frequency modulated intensity signal
D	Color is sent in a color burst at the end of each line

10. - E2C07

What is the Cabrillo format?

Select	Answer
A	A method of exchanging information during a contest QSO
B	The rules of order for meetings between contest sponsors
C	A standard for submission of electronic contest logs
D	The most common set of contest rules

11. - E2D07

What digital protocol is used by APRS?

Select	Answer
A	AX.25
B	AMTOR
C	802.11
D	PACTOR

12. - E2E06

What is the most common data rate used for HF packet?

Select	Answer
A	300 baud
B	1200 baud
C	48 baud
D	110 baud

13. - E3A11

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

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

14. - E3B04

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

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

15. - E3C08

What does the space weather term G5 mean?

Select	Answer
A	An extreme geomagnetic storm
B	Waning sunspot numbers
C	Very low solar activity
D	Moderate solar wind

16. - E4A05

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

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

17. - E4B01

Which of the following factors most affects the accuracy of a frequency counter?

Select	Answer
A	Time base accuracy
B	Decade divider accuracy
C	Temperature coefficient of the logic
D	Input attenuator accuracy

18. - E4C01

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

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

19. - E4D09

What is the purpose of the preselector in a communications receiver?

Select	Answer
A	To store often-used frequencies
B	To allow selection of the optimum RF amplifier device
C	To provide a range of AGC time constants
D	To increase rejection of signals outside the desired band

20. - E4E08

What current flows equally on all conductors of an unshielded multi-conductor cable?

Select	Answer
A	Differential-mode current
B	Common-mode current
C	Reactive current only
D	Return current

21. - E5A03

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

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

22. - E5B07

What is the phase angle between the voltage across and the current through a series RLC circuit if XC is 500 ohms, R is 1 kilohm, and XL is 250 ohms?

Select	Answer
A	14.0 degrees with the voltage lagging the current
B	14.0 degrees with the voltage leading the current
C	68.2 degrees with the voltage leading the current
D	68.2 degrees with the voltage lagging the current

23. - E5C10

Which point on Figure E5-1 best represents the impedance of a series circuit consisting of a 400-ohm resistor and a 38-picofarad capacitor at 14 MHz?

Select	Answer
A	Point 5
B	Point 6
C	Point 4
D	Point 2

24. - E5D09

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

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

25. - E6A09

What is a depletion-mode FET?

Select	Answer
A	Any FET without a channel
B	An FET that exhibits a current flow between source and drain when no gate voltage is applied
C	An FET that has no current flow between source and drain when no gate voltage is applied
D	Any FET for which holes are the majority carriers

26. - E6B07

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

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

27. - E6C02

What happens when the level of a comparator's input signal crosses the threshold?

Select	Answer
A	The IC input can be damaged
B	The comparator changes its output state
C	The feedback loop becomes unstable
D	The comparator enters latch-up

28. - E6D01

Why should core saturation of an impedance matching transformer be avoided?

Select	Answer
A	Harmonics and distortion could result
B	Magnetic flux would increase with frequency
C	RF susceptance would increase
D	Temporary changes of the core permeability could result

29. - E6E12

Why are DIP through-hole package ICs not typically used at UHF and higher frequencies?

Select	Answer
A	Unsuitable for combining analog and digital signals
B	Epoxy coating is conductive above 300 MHz
C	Too many pins
D	Excessive lead length

30. - E6F09

What is the efficiency of a photovoltaic cell?

Select	Answer
A	The open-circuit voltage divided by the short-circuit current under full illumination
B	The output RF power divided by the input DC power
C	The relative fraction of light that is converted to current
D	Cost per kilowatt-hour generated

31. - E7A09

What logical operation is performed by an exclusive NOR gate?

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

32. - E7B14

Why are switching amplifiers more efficient than linear amplifiers?

Select	Answer
A	Switching amplifiers operate at higher voltages
B	The power transistor is at saturation or cutoff most of the time
C	Switching amplifiers use push-pull circuits
D	Linear amplifiers have high gain resulting in higher harmonic content

33. - E7C03

What advantage does a series-L Pi-L-network have over a series-L Pi-network for impedance matching between the final amplifier of a vacuum-tube transmitter and an antenna?

Select	Answer
A	Greater harmonic suppression
B	Does not require a capacitor
C	Greater transformation range
D	Higher efficiency

34. - E7D13

What is the equation for calculating power dissipated by a series linear voltage regulator?

Select	Answer
A	Input voltage multiplied by input current
B	Voltage difference from input to output multiplied by output current
C	Input voltage divided by output current
D	Output voltage multiplied by output current

35. - E7E05

What circuit is added to an FM transmitter to boost the higher audio frequencies?

Select	Answer
A	A heterodyne enhancer
B	A pre-emphasis network
C	A de-emphasis network
D	A heterodyne suppressor

36. - E7F09

Why is an anti-aliasing digital filter required in a digital decimator?

Select	Answer
A	It removes high-frequency signal components that would otherwise be reproduced as lower frequency components
B	It peaks the response of the decimator, improving bandwidth
C	It removes low-frequency signal components to eliminate the need for DC restoration
D	It notches out the sampling frequency to avoid sampling errors

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 differential input voltage needed to bring the open loop output voltage to zero
D	The output voltage of the op-amp minus its input voltage

38. - E7H03

How is positive feedback supplied in a Hartley oscillator?

Select	Answer
A	Through a neutralizing capacitor
B	Through link coupling
C	Through a capacitive divider
D	Through a tapped coil

39. - E8A09

How many different input levels can be encoded by an analog-to-digital converter with 8-bit resolution?

Select	Answer
A	256
B	8
C	256 divided by the gain of the input amplifier
D	8 multiplied by the gain of the input amplifier

40. - E8B10

What is frequency division multiplexing?

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

41. - E8C02

What is the definition of symbol rate in a digital transmission?

Select	Answer
A	The number of characters carried per second by the station-to-station link
B	The rate at which the waveform changes to convey information
C	The number of control characters in a message packet
D	The duration of each bit in a message sent over the air

42. - E8D09

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

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

43. - E9A02

What is the effective radiated power relative to a dipole of a repeater station with 150 watts transmitter power output, 2 dB feed line loss, 2.2 dB duplexer loss, and 7 dBd antenna gain?

Select	Answer
A	78.7 watts
B	1977 watts
C	286 watts
D	420 watts

44. - E9B11

What is a disadvantage of decreasing the number of wire segments in an antenna model below 10 segments per half-wavelength?

Select	Answer
A	Ground conductivity will not be accurately modeled
B	The resulting design will favor radiation of harmonic energy
C	The antenna will become mechanically unstable
D	The computed feed point impedance may be incorrect

45. - E9C06

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

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

46. - E9D10

What happens to feed-point impedance at the base of a fixed length HF mobile antenna when operated below its resonant frequency?

Select	Answer
A	The radiation resistance increases and the capacitive reactance increases
B	The radiation resistance decreases and the capacitive reactance increases
C	The radiation resistance increases and the capacitive reactance decreases
D	The radiation resistance decreases and the capacitive reactance decreases

47. - E9E03

What is the name of the matching system that uses a section of transmission line connected in parallel with the feed line at or near the feed point?

Select	Answer
A	The gamma match
B	The stub match
C	The delta match
D	The omega match

48. - E9F02

Which of the following has the biggest effect on the velocity factor of a transmission line?

Select	Answer
A	The center conductor resistivity
B	The line length
C	Dielectric materials used in the line
D	The termination impedance

49. - E9G08

What is the process of normalization with regard to a Smith chart?

Select	Answer
A	Reassigning resistance values with regard to the reactance axis
B	Reassigning reactance values with regard to the resistance axis
C	Reassigning impedance values with regard to the prime center
D	Reassigning prime center with regard to the reactance axis

50. - E9H08

What is the function of a sense antenna?

Select	Answer
A	It provides diversity reception that cancels multipath signals
B	It allows DF antennas to receive signals at different vertical angles
C	It increases the sensitivity of a DF antenna array
D	It modifies the pattern of a DF antenna array to provide a null in one direction

Figure E5-1