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

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1. - E0A10

What toxic material may be present in some electronic components such as high voltage capacitors and transformers?

Select	Answer
A	Polytetrafluoroethylene
B	Polymorphic silicon
C	Polychlorinated biphenyls
D	Polyethylene

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

3. - E1B08

What limitations may the FCC place on an amateur station if its signal causes interference to domestic broadcast reception, assuming that the receivers involved are of good engineering design?

Select	Answer
A	The amateur station must cease operation on all frequencies below 30 MHz
B	The amateur station must cease operation
C	The amateur station must cease operation on all frequencies above 30 MHz
D	The amateur station must avoid transmitting during certain hours on frequencies that cause the interference

4. - E1C11

Which of the following operating arrangements allows an FCC-licensed U.S. citizen to operate in many European countries, and alien amateurs from many European countries to operate in the U.S.?

Select	Answer
A	ITU reciprocal license
B	CEPT agreement
C	IARP agreement
D	All these choices are correct

5. - E1D05

What must be posted at the station location of a station being operated by telecommand on or within 50 km of the earth's surface?

Select	Answer
A	A photocopy of the station license
B	All these choices are correct
C	A label with the name, address, and telephone number of the station licensee
D	A label with the name, address, and telephone number of the control operator

6. - E1E02

Who does Part 97 task with maintaining the pools of questions for all U.S. amateur license examinations?

Select	Answer
A	The FCC
B	The VECs
C	The VEs
D	The ARRL

7. - E1F09

Which of the following conditions apply when transmitting spread spectrum emissions?

Select	Answer
A	The transmitting station must be in an area regulated by the FCC or in a country that permits SS emissions
B	A station transmitting SS emission must not cause harmful interference to other stations employing other authorized emissions
C	All these choices are correct
D	The transmission must not be used to obscure the meaning of any communication

8. - E2A10

What type of satellite appears to stay in one position in the sky?

Select	Answer
A	LEO
B	HEO
C	Geostationary
D	Geomagnetic

9. - E2B04

How is color information sent in analog SSTV?

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

10. - E2C03

From which of the following bands is amateur radio contesting generally excluded?

Select	Answer
A	33 centimeters
B	30 meters
C	2 meters
D	6 meters

11. - E2D07

What digital protocol is used by APRS?

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

12. - E2E12

How do ALE stations establish contact?

Select	Answer
A	ALE radios send a constant tone code to establish a frequency for future use
B	ALE constantly scans a list of frequencies, activating the radio when the designated call sign is received
C	ALE radios monitor an internet site for the frequency they are being paged on
D	ALE radios activate when they hear their signal echoed by back scatter

13. - E3A01

What is the approximate maximum separation measured along the surface of the Earth between two stations communicating by EME?

Select	Answer
A	5000 miles, if the moon is at perigee
B	500 miles, if the moon is at perigee
C	2000 miles, if the moon is at apogee
D	12,000 miles, if the moon is visible by both stations

14. - E3B12

What is the primary characteristic of chordal hop propagation?

Select	Answer
A	Signals reflected back toward the transmitting station
B	Successive ionospheric refractions without an intermediate reflection from the ground
C	Propagation across the geomagnetic equator
D	Propagation away from the great circle bearing between stations

15. - E3C14

Why does the radio-path horizon distance exceed the geometric horizon?

Select	Answer
A	D-region skip
B	Due to the Doppler effect
C	E-region skip
D	Downward bending due to density variations in the atmosphere

16. - E4A06

What is the effect of aliasing on a digital oscilloscope caused by setting the time base too slow?

Select	Answer
A	A false, jittery low-frequency version of the signal is displayed
B	Excessive blanking occurs, which prevents display of the signal
C	All signals will have a DC offset
D	Calibration of the vertical scale is no longer valid

17. - E4B01

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

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

18. - E4C09

Which of the following choices is a good reason for selecting a high frequency for the design of the IF in a superheterodyne HF or VHF communications receiver?

Select	Answer
A	Reduced drift
B	Easier for front-end circuitry to eliminate image responses
C	Fewer components in the receiver
D	Improved receiver noise figure

19. - E4D11

Why are odd-order intermodulation products, created within a receiver, of particular interest compared to other products?

Select	Answer
A	Odd-order products of two signals in the band of interest are also likely to be within the band
B	Odd-order intermodulation produces three products for every input signal within the band of interest
C	Odd-order products are an indication of poor image rejection
D	Odd-order products overload the IF filters

20. - E4E03

Which of the following signals might a receiver noise blanker be able to remove from desired signals?

Select	Answer
A	Signals that have a sharply peaked frequency distribution
B	Signals that are constant at all IF levels
C	Signals that appear across a wide bandwidth
D	Signals that appear at one IF but not another

21. - E5A12

What is the half-power bandwidth of a resonant circuit that has a resonant frequency of 3.7 MHz and a Q of 118?

Select	Answer
A	15.7 kHz
B	31.4 kHz
C	436.6 kHz
D	218.3 kHz

22. - E5B01

What is the term for the time required for the capacitor in an RC circuit to be charged to 63.2% of the applied voltage or to discharge to 36.8% of its initial voltage?

Select	Answer
A	An exponential rate of one
B	One exponential period
C	A time factor of one
D	One time constant

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 2
C	Point 4
D	Point 6

24. - E5D07

How many watts are consumed in a circuit having a power factor of 0.71 if the apparent power is 500VA?

Select	Answer
A	252 W
B	355 W
C	704 W
D	1.42 mW

25. - E6A03

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

Select	Answer
A	Excess holes in P-type material combine with the electrons in N-type material, converting the entire diode into an insulator
B	Only N-type semiconductor material can conduct current
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 P-type semiconductor material can conduct current

26. - E6B10

In Figure E6-2, what is the schematic symbol for a light-emitting diode?

Select	Answer
A	5
B	7
C	6
D	1

27. - E6C10

In Figure E6-3, what is the schematic symbol for a NOR gate?

Select	Answer
A	3
B	2
C	4
D	1

28. - E6D11

Which type of core material decreases inductance when inserted into a coil?

Select	Answer
A	Ferrite
B	Brass
C	Ceramic
D	Powdered iron

29. - E6E06

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

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

30. - E6F03

What is the most common configuration of an optoisolator or optocoupler?

Select	Answer
A	An LED and a phototransistor
B	A frequency modulated helium-neon laser
C	An amplitude modulated helium-neon laser
D	A lens and a photomultiplier

31. - E7A07

What logical operation does a NAND gate perform?

Select	Answer
A	It produces logic 0 at its output only when all inputs are logic 1
B	It produces logic 0 at its output only when all inputs are logic 0
C	It produces logic 1 at its output only when all inputs are logic 1
D	It produces logic 0 at its output if some but not all inputs are logic 1

32. - E7B17

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

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

33. - E7C06

What are the distinguishing features of an elliptical filter?

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

34. - E7D14

What is the purpose of connecting equal-value resistors across power supply filter capacitors connected in series?

Select	Answer
A	Provide a minimum load on the supply
B	Equalize the voltage across each capacitor
C	All these choices are correct
D	Discharge the capacitors when voltage is removed

35. - E7E01

Which of the following can be used to generate FM phone emissions?

Select	Answer
A	A balanced modulator on the audio amplifier
B	A reactance modulator on the final amplifier
C	A balanced modulator on the oscillator
D	A reactance modulator on the oscillator

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

37. - E7G06

What is the gain-bandwidth of an operational amplifier?

Select	Answer
A	The gain of the amplifier at a filter's cutoff frequency
B	The frequency at which the amplifier's offset voltage is zero
C	The maximum frequency for a filter circuit using that type of amplifier
D	The frequency at which the open-loop gain of the amplifier equals one

38. - E7H07

How can an oscillator's microphonic responses be reduced?

Select	Answer
A	Reduce noise on the oscillator's power supply
B	Use NP0 capacitors
C	Increase the bias voltage
D	Mechanically isolate the oscillator circuitry from its enclosure

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. - E8B03

What is the modulation index of an FM-phone signal having a maximum frequency deviation of 3000 Hz either side of the carrier frequency when the modulating frequency is 1000 Hz?

Select	Answer
A	0.3
B	1000
C	3000
D	3

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 number of control characters in a message packet
C	The duration of each bit in a message sent over the air
D	The rate at which the waveform changes to convey information

42. - E8D01

Why are received spread spectrum signals resistant to interference?

Select	Answer
A	The receiver is always equipped with a digital blanker
B	If interference is detected by the receiver it will signal the transmitter to change frequencies
C	Signals not using the spread spectrum algorithm are suppressed in the receiver
D	The high power used by a spread spectrum transmitter keeps its signal from being easily overpowered

43. - E9A13

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

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

44. - E9B04

What is the front-to-back ratio of the radiation pattern shown in Figure E92?

Select	Answer
A	28 dB
B	3 dB
C	15 dB
D	38 dB

45. - E9C14

How does the performance of a horizontally polarized antenna mounted on the side of a hill compare with the same antenna mounted on flat ground?

Select	Answer
A	The main lobe takeoff angle increases in the downhill direction
B	The horizontal beamwidth decreases in the downhill direction
C	The horizontal beamwidth increases in the uphill direction
D	The main lobe takeoff angle decreases in the downhill direction

46. - E9D08

What happens as the Q of an antenna increases?

Select	Answer
A	Gain is reduced
B	SWR bandwidth increases
C	SWR bandwidth decreases
D	More common-mode current is present on the feed line

47. - E9E09

Which of the following is used to shunt-feed a grounded tower at its base?

Select	Answer
A	Hairpin match
B	Gamma match
C	Double-bazooka match
D	All these choices are correct

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

49. - E9G07

On the Smith chart shown in Figure E9-3, what is the only straight line shown?

Select	Answer
A	The reactance axis
B	The resistance axis
C	The voltage axis
D	The current axis

50. - E9H06

What is the triangulation method of direction finding?

Select	Answer
A	Antenna headings from several different receiving locations are used to locate the signal source
B	The geometric angles of sky waves from the source are used to determine its position
C	A fixed receiving station uses three different antennas to plot the location of the signal source
D	A fixed receiving station plots three headings to the signal source

Figure E5-1

Figure E6-2

Figure E6-3

Figure E9-3