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	Uranium Hexafluoride
B	Mica
C	Beryllium Oxide
D	Zinc oxide

2. - E1A07

What is the maximum power permitted on the 2200 meter band?

Select	Answer
A	50 watts PEP
B	5 watts EIRP (Equivalent isotropic radiated power)
C	100 watts PEP
D	1 watt EIRP (Equivalent isotropic radiated power)

3. - E1B03

Within what distance must an amateur station protect an FCC monitoring facility from harmful interference?

Select	Answer
A	10 miles
B	30 miles
C	3 miles
D	1 mile

4. - E1C09

What is the highest modulation index permitted at the highest modulation frequency for angle modulation below 29.0 MHz?

Select	Answer
A	1.0
B	2.0
C	0.5
D	3.0

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	Binary control characters
C	Data containing personal information
D	Telecommand signals from a space telecommand station

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

7. - E1F04

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

Select	Answer
A	A line roughly parallel to and north of the border between the U.S. and Mexico
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 south of the border between the U.S. and Canada

8. - E2A05

What do the letters in a satellite's mode designator specify?

Select	Answer
A	The polarization of uplink and downlink signals
B	The uplink and downlink frequency ranges
C	Power limits for uplink and downlink transmissions
D	The location of the ground control station

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 is amplitude modulated on the frequency modulated intensity signal
C	Color lines are sent sequentially
D	Color is sent in a color burst at the end of each line

10. - E2C12

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

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

11. - E2D10

How can an APRS station be used to help support a public service communications activity?

Select	Answer
A	All these choices are correct
B	An APRS station with a Global Positioning System unit can automatically transmit information to show a mobile station's position during the event
C	APRS stations with General Personnel Scanners can automatically relay the participant numbers and time as they pass the check points
D	An APRS station with an emergency medical technician can automatically transmit medical data to the nearest hospital

12. - E2E08

Which of the following HF digital modes can be used to transfer binary files?

Select	Answer
A	Hellschreiber
B	PACTOR
C	AMTOR
D	RTTY

13. - E3A01

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

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

14. - E3B01

What is transequatorial propagation?

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

15. - E3C15

What might be indicated by a sudden rise in radio background noise across a large portion of the HF spectrum?

Select	Answer
A	A temperature inversion has occurred
B	Increased transequatorial propagation is likely
C	A solar flare has occurred
D	Long-path propagation is likely

16. - E4A04

How is the compensation of an oscilloscope probe typically adjusted?

Select	Answer
A	A high frequency sine wave is displayed and the probe is adjusted for maximum amplitude
B	A DC voltage standard is displayed and the probe is adjusted until the displayed voltage is accurate
C	A frequency standard is displayed and the probe is adjusted until the deflection time is accurate
D	A square wave is displayed and the probe is adjusted until the horizontal portions of the displayed wave are as nearly flat as possible

17. - E4B06

How much power is being absorbed by the load when a directional power meter connected between a transmitter and a terminating load reads 100 watts forward power and 25 watts reflected power?

Select	Answer
A	100 watts
B	125 watts
C	25 watts
D	75 watts

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	Fewer components in the receiver
C	Easier for front-end circuitry to eliminate image responses
D	Improved receiver noise figure

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	Intermodulation
B	Adjacent channel interference
C	Neutralization
D	Amplifier desensitization

20. - E4E04

How can conducted and radiated noise caused by an automobile alternator be suppressed?

Select	Answer
A	By installing a noise suppression resistor and a blocking capacitor in both leads
B	By installing filter capacitors in series with the DC power lead and a blocking capacitor in the field lead
C	By installing a high-pass filter in series with the radio's power lead and a low-pass filter in parallel with the field lead
D	By connecting the radio's power leads directly to the battery and by installing coaxial capacitors in line with the alternator leads

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	44.72 MHz
B	3.56 MHz
C	1.78 MHz
D	22.36 MHz

22. - E5B04

What is the time constant of a circuit having two 220-microfarad capacitors and two 1-megohm resistors, all in parallel?

Select	Answer
A	55 seconds
B	220 seconds
C	440 seconds
D	110 seconds

23. - E5C04

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

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

24. - E5D04

Why are short connections used at microwave frequencies?

Select	Answer
A	To increase neutralizing resistance
B	To reduce phase shift along the connection
C	To increase compensating capacitance
D	To reduce noise figure

25. - E6A02

Which of the following semiconductor materials contains excess free electrons?

Select	Answer
A	P-type
B	Bipolar
C	N-type
D	Insulated gate

26. - E6B11

What is used to control the attenuation of RF signals by a PIN diode?

Select	Answer
A	Capacitance of an RF coupling capacitor
B	A sub-harmonic pump signal
C	Forward DC bias current
D	Reverse voltage larger than the RF signal

27. - E6C10

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

Select	Answer
A	1
B	4
C	2
D	3

28. - E6D03

Which of the following is an aspect of the piezoelectric effect?

Select	Answer
A	Generation of electrical energy in the presence of light
B	Increased conductivity in the presence of light
C	Mechanical deformation of material by the application of a magnetic field
D	Mechanical deformation of material by the application of a voltage

29. - E6E08

How is power supplied to the most common type of MMIC?

Select	Answer
A	MMICs require no operating bias
B	Through a resistor and/or RF choke connected to the amplifier output lead
C	Through a capacitor and RF choke connected to the amplifier input lead
D	Directly to the bias voltage (VCC IN) lead

30. - E6F06

Which of these materials is most commonly used to create photoconductive devices?

Select	Answer
A	A crystalline semiconductor
B	A liquid semiconductor
C	A heavy metal
D	An ordinary metal

31. - E7A05

Which of the following is a circuit that continuously alternates between two states without an external clock?

Select	Answer
A	J-K flip-flop
B	Monostable multivibrator
C	Astable multivibrator
D	T flip-flop

32. - E7B02

What is a Class D amplifier?

Select	Answer
A	A frequency doubling amplifier
B	A low power amplifier that uses a differential amplifier for improved linearity
C	An amplifier that uses drift-mode FETs for high efficiency
D	A type of amplifier that uses switching technology to achieve high efficiency

33. - E7C08

Which of the following factors has the greatest effect on the bandwidth and response shape of a crystal ladder filter?

Select	Answer
A	The relative frequencies of the individual crystals
B	The amplitude of the signals passing through the filter
C	The DC voltage applied to the quartz crystal
D	The gain of the RF stage preceding the 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 shunt current source
B	A shunt regulator
C	A series regulator
D	A constant current source

35. - E7E01

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

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

36. - E7F04

What is a common method of generating an SSB signal using digital signal processing?

Select	Answer
A	Varying quartz crystal characteristics emulated in digital form
B	A frequency synthesizer removes the unwanted sidebands
C	Mixing products are converted to voltages and subtracted by adder circuits
D	Signals are combined in quadrature phase relationship

37. - E7G01

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

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

38. - E7H11

What are the major spectral impurity components of direct digital synthesizers?

Select	Answer
A	Digital conversion noise
B	Spurious signals at discrete frequencies
C	Nyquist limit noise
D	Broadband noise

39. - E8A06

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

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

40. - E8B10

What is frequency division multiplexing?

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

41. - E8C12

What factors affect the bandwidth of a transmitted CW signal?

Select	Answer
A	Keying speed and shape factor (rise and fall time)
B	All these choices are correct
C	Modulation index and output power
D	IF bandwidth and Q

42. - E8D06

What is the advantage of including parity bits in ASCII characters?

Select	Answer
A	Some types of errors can be detected
B	Faster transmission rate
C	The signal can overpower interfering signals
D	Foreign language characters can be sent

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	420 watts
B	78.7 watts
C	286 watts
D	1977 watts

44. - E9B08

What is the far field of an antenna?

Select	Answer
A	The region where the shape of the antenna pattern is independent of distance
B	The region of the ionosphere where radiated power is not refracted
C	The region where radiated power dissipates over a specified time period
D	The region where radiated field strengths are constant

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

46. - E9D06

What happens to the SWR bandwidth when one or more loading coils are used to resonate an electrically short antenna?

Select	Answer
A	It is increased
B	It is unchanged if the loading coil is located at a voltage maximum point
C	It is unchanged if the loading coil is located at the feed point
D	It is decreased

47. - E9E09

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

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

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

49. - E9G09

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

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

50. - E9H07

Why is RF attenuation used when direction-finding?

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

Figure E6-3