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	Beryllium Oxide
C	Uranium Hexafluoride
D	Zinc oxide

2. - E1A12

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

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

3. - E1B12

What must the control operator of a repeater operating in the 70 cm band do if a radiolocation system experiences interference from that repeater?

Select	Answer
A	Reduce the repeater antenna HAAT (Height Above Average Terrain)
B	Cease operation or make changes to the repeater to mitigate the interference
C	All these choices are correct
D	File an FAA NOTAM (Notice to Airmen) with the repeater system's ERP, call sign, and six-character grid locator

4. - E1C04

What is meant by IARP?

Select	Answer
A	The internal amateur radio practices policy of the FCC
B	An international amateur radio permit that allows U.S. amateurs to operate in certain countries of the Americas
C	A forecast of intermittent aurora radio propagation
D	An indication of increased antenna reflected power

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	Binary control characters
D	Data containing personal information

6. - E1E09

What may be the penalty for a VE who fraudulently administers or certifies an examination?

Select	Answer
A	Revocation of the VE's amateur station license grant and the suspension of the VE's amateur operator license grant
B	A fine of up to $1000 per occurrence
C	A sentence of up to one year in prison
D	All these choices are correct

7. - E1F11

Which of the following best describes one of the standards that must be met by an external RF power amplifier if it is to qualify for a grant of FCC certification?

Select	Answer
A	It must exhibit a gain of 0 dB or less over its full output range
B	It must produce full legal output when driven by not more than 5 watts of mean RF input power
C	It must satisfy the FCC's spurious emission standards when operated at the lesser of 1500 watts or its full output power
D	It must be capable of external RF switching between its input and output networks

8. - E2A10

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

Select	Answer
A	Geostationary
B	HEO
C	Geomagnetic
D	LEO

9. - E2B08

What technique allows commercial analog TV receivers to be used for fast-scan TV operations on the 70 cm band?

Select	Answer
A	Transmitting on channels shared with cable TV
B	Transmitting on the abandoned TV channel 2
C	Using USB and demodulating the signal with a computer sound card
D	Using converted satellite TV dishes

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 2 meter VHF transceiver with a 1200 baud modem
C	A wireless router running custom firmware
D	An optical cable connection between the USB ports of 2 separate computers

11. - E2D09

What type of modulation is used for JT65 contacts?

Select	Answer
A	PSK
B	IEEE 802.11
C	Multi-tone AFSK
D	RTTY

12. - E2E10

Which of these digital modes has the narrowest bandwidth?

Select	Answer
A	MFSK16
B	170 Hz shift, 45-baud RTTY
C	300-baud packet
D	PSK31

13. - E3A02

What characterizes libration fading of an EME signal?

Select	Answer
A	A gradual loss of signal as the sun rises
B	A fluttery irregular fading
C	The returning echo is several hertz lower in frequency than the transmitted signal
D	A slow change in the pitch of the CW signal

14. - E3B02

What is the approximate maximum range for signals using transequatorial propagation?

Select	Answer
A	2500 miles
B	7500 miles
C	1000 miles
D	5000 miles

15. - E3C14

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

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

16. - E4A05

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

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

17. - E4B10

Which of the following methods measures intermodulation distortion in an SSB transmitter?

Select	Answer
A	Modulate the transmitter using two RF signals having non-harmonically related frequencies and observe the RF output with a spectrum analyzer
B	Modulate the transmitter using two RF signals having harmonically related frequencies and observe the RF output with a logic analyzer
C	Modulate the transmitter using two AF signals having non-harmonically related frequencies and observe the RF output with a spectrum analyzer
D	Modulate the transmitter using two AF signals having harmonically related frequencies and observe the RF output with a peak reading wattmeter

18. - E4C14

What transmit frequency might generate an image response signal in a receiver tuned to 14.300 MHz and that uses a 455 kHz IF frequency?

Select	Answer
A	14.755 MHz
B	13.845 MHz
C	15.210 MHz
D	14.445 MHz

19. - E4D12

What is the term for the reduction in receiver sensitivity caused by a strong signal near the received frequency?

Select	Answer
A	Desensitization
B	Quieting
C	Cross-modulation interference
D	Squelch gain rollback

20. - E4E01

What problem can occur when using an automatic notch filter (ANF) to remove interfering carriers while receiving CW signals?

Select	Answer
A	Received CW signals will appear to be modulated at the DSP clock frequency
B	Any nearby signal passing through the DSP system will overwhelm the desired signal
C	Removal of the CW signal as well as the interfering carrier
D	Ringing in the DSP filter will completely remove the spaces between the CW characters

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	1.78 MHz
B	22.36 MHz
C	44.72 MHz
D	3.56 MHz

22. - E5B06

What is susceptance?

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

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 7
B	Point 3
C	Point 8
D	Point 1

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	355 W
B	252 W
C	1.42 mW
D	704 W

25. - E6A10

In Figure E6-1, what is the schematic symbol for an N-channel dual-gate MOSFET?

Select	Answer
A	4
B	5
C	2
D	6

26. - E6B07

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

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

27. - E6C05

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

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

28. - E6D04

Which materials are commonly used as a core in an inductor?

Select	Answer
A	Teflon and Delrin
B	Polystyrene and polyethylene
C	Cobalt and aluminum
D	Ferrite and brass

29. - E6E04

Which is the most common input and output impedance of circuits that use MMICs?

Select	Answer
A	450 ohms
B	300 ohms
C	10 ohms
D	50 ohms

30. - E6F05

Which describes an optical shaft encoder?

Select	Answer
A	A device for generating RTTY signals by means of a rotating light source
B	A device that measures the strength of a beam of light using analog to digital conversion
C	A device that detects rotation of a control by interrupting a light source with a patterned wheel
D	A digital encryption device often used to encrypt spacecraft control signals

31. - E7A06

What is a characteristic of a monostable multivibrator?

Select	Answer
A	It stores one bit of data in either a 0 or 1 state
B	It produces a continuous square wave oscillating between 1 and 0
C	It maintains a constant output voltage, regardless of variations in the input voltage
D	It switches momentarily to the opposite binary state and then returns to its original state after a set time

32. - E7B11

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

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

33. - E7C09

What is a crystal lattice filter?

Select	Answer
A	A power supply filter made with interlaced quartz crystals
B	An audio filter made with four quartz crystals that resonate at 1 kHz intervals
C	A filter with narrow bandwidth and steep skirts made using quartz crystals
D	A filter using lattice-shaped quartz crystals for high-Q performance

34. - E7D11

What is the function of the pass transistor in a linear voltage regulator circuit?

Select	Answer
A	Maintains nearly constant output voltage over a wide range of load current
B	Provides a stable input impedance over a wide range of source voltage
C	Maintains nearly constant output impedance over a wide range of load current
D	Permits a wide range of output voltage settings

35. - E7E03

What is a frequency discriminator stage in a FM receiver?

Select	Answer
A	An FM generator circuit
B	A circuit for filtering two closely adjacent signals
C	A circuit for detecting FM signals
D	An automatic band-switching circuit

36. - E7F13

What is the function of taps in a digital signal processing filter?

Select	Answer
A	Select the point at which baseband signals are generated
B	To reduce excess signal pressure levels
C	Provide incremental signal delays for filter algorithms
D	Provide access for debugging software

37. - E7G01

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

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

38. - E7H08

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

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

39. - E8A01

What is the name of the process that shows that a square wave is made up of a sine wave plus all its odd harmonics?

Select	Answer
A	Fourier analysis
B	Differential analysis
C	Numerical analysis
D	Vector analysis

40. - E8B01

What is the modulation index of an FM signal?

Select	Answer
A	The bandwidth of the transmitted signal divided by the modulating signal frequency
B	The ratio of modulating signal amplitude to frequency deviation
C	The type of modulation used by the transmitter
D	The ratio of frequency deviation to modulating signal frequency

41. - E8C06

What is the bandwidth of a 170-hertz shift, 300-baud ASCII transmission?

Select	Answer
A	1.0 kHz
B	0.1 Hz
C	0.3 kHz
D	0.5 kHz

42. - E8D07

What is a common cause of overmodulation of AFSK signals?

Select	Answer
A	Excessive numbers of retries
B	Ground loops
C	Bit errors in the modem
D	Excessive transmit audio levels

43. - E9A04

Which of the following factors affect the feed point impedance of an antenna?

Select	Answer
A	Transmission line length
B	The settings of an antenna tuner at the transmitter
C	The input power level
D	Antenna height

44. - E9B04

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

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

45. - E9C03

What is the radiation pattern of two 1/4-wavelength vertical antennas spaced 1/2-wavelength apart and fed in phase?

Select	Answer
A	A Figure-8 end-fire along the axis of the array
B	Omni-directional
C	Cardioid
D	A Figure-8 broadside to the axis of the array

46. - E9D11

Which of the following conductors would be best for minimizing losses in a station's RF ground system?

Select	Answer
A	Stranded wire
B	Wide flat copper strap
C	Solid wire
D	Resistive wire, such as spark plug wire

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 delta match
B	The stub match
C	The omega match
D	The gamma match

48. - E9F08

Which of the following is a significant difference between foam dielectric coaxial cable and solid dielectric cable, assuming all other parameters are the same?

Select	Answer
A	Foam dielectric has lower loss per unit of length
B	All these choices are correct
C	Foam dielectric has lower safe operating voltage limits
D	Foam dielectric has higher velocity factor

49. - E9G11

How are the wavelength scales on a Smith chart calibrated?

Select	Answer
A	In fractions of antenna electrical frequency
B	In fractions of antenna electrical wavelength
C	In fractions of transmission line electrical frequency
D	In fractions of transmission line electrical wavelength

50. - E9H08

What is the function of a sense antenna?

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

Figure E5-1

Figure E6-1

Figure E7-1