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	Zinc oxide
C	Beryllium Oxide
D	Mica

2. - E1A10

If an amateur station is installed aboard a ship or aircraft, what condition must be met before the station is operated?

Select	Answer
A	The amateur station operator must agree not to transmit when the main radio of the ship or aircraft is in use
B	Its operation must be approved by the master of the ship or the pilot in command of the aircraft
C	The amateur operator must have an FCC Marine or Aircraft endorsement on his or her amateur license
D	The amateur station must have a power supply that is completely independent of the main ship or aircraft power supply

3. - E1B06

Which of the following additional rules apply if you are installing an amateur station antenna at a site at or near a public use airport?

Select	Answer
A	You may have to notify the Federal Aviation Administration and register it with the FCC as required by Part 17 of the FCC rules
B	You must file an Environmental Impact Statement with the EPA before construction begins
C	You must obtain a construction permit from the airport zoning authority
D	You must submit engineering drawings to the FAA

4. - E1C12

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

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

5. - E1D08

Which VHF amateur bands have frequencies authorized for space stations?

Select	Answer
A	2 meters and 1.25 meters
B	2 meters
C	6 meters, 2 meters, and 1.25 meters
D	6 meters and 2 meters

6. - E1E08

To which of the following examinees may a VE not administer an examination?

Select	Answer
A	Friends of the VE
B	Employees of the VE
C	Relatives of the VE as listed in the FCC rules
D	All these choices are correct

7. - E1F07

When may an amateur station send a message to a business?

Select	Answer
A	When the total money involved does not exceed $25
B	When transmitting international third-party communications
C	When the control operator is employed by the FCC or another government agency
D	When neither the amateur nor his or her employer has a pecuniary interest in the communications

8. - E2A06

What are Keplerian elements?

Select	Answer
A	Phase reversing elements in a Yagi antenna
B	High-emission heater filaments used in magnetron tubes
C	Parameters that define the orbit of a satellite
D	Encrypting codes used for spread spectrum modulation

9. - E2B09

What hardware, other than a receiver with SSB capability and a suitable computer, is needed to decode SSTV using Digital Radio Mondiale (DRM)?

Select	Answer
A	A special IF converter
B	A special front end limiter
C	No other hardware is needed
D	A special notch filter to remove synchronization pulses

10. - E2C03

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

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

11. - E2D01

Which of the following digital modes is designed for meteor scatter communications?

Select	Answer
A	APRS
B	Hellschreiber
C	MSK144
D	WSPR

12. - E2E11

What is the difference between direct FSK and audio FSK?

Select	Answer
A	Direct FSK applies the data signal to the transmitter VFO, while AFSK transmits tones via phone
B	Direct FSK occupies less bandwidth
C	Only direct FSK can be decoded by computer
D	Direct FSK can transmit faster baud rates

13. - E3A09

Which of the following frequency ranges is most suited for meteor scatter communications?

Select	Answer
A	220 MHz - 450 MHz
B	10 MHz - 14 MHz
C	28 MHz - 148 MHz
D	1.8 MHz - 1.9 MHz

14. - E3B06

Which of the following amateur bands most frequently provides long-path propagation?

Select	Answer
A	20 meters
B	6 meters
C	80 meters
D	10 meters

15. - E3C01

What does the radio communication term "ray tracing" describe?

Select	Answer
A	The process in which an electronic display presents a pattern
B	Modeling a radio wave's path through the ionosphere
C	Determining the radiation pattern from an array of antennas
D	Evaluating high voltage sources for x-rays

16. - E4A11

How should an antenna analyzer be connected when measuring antenna resonance and feed point impedance?

Select	Answer
A	Connect the antenna feed line directly to the analyzer's connector
B	Loosely couple the analyzer near the antenna base
C	Loosely couple the antenna and a dummy load to the analyzer
D	Connect the analyzer via a high-impedance transformer to the antenna

17. - E4B08

Which of the following can be used to measure the Q of a series-tuned circuit?

Select	Answer
A	The frequency shift
B	The bandwidth of the circuit's frequency response
C	The resonant frequency of the circuit
D	The inductance to capacitance ratio

18. - E4C06

A CW receiver with the AGC off has an equivalent input noise power density of -174 dBm/Hz. What would be the level of an unmodulated carrier input to this receiver that would yield an audio output SNR of 0 dB in a 400 Hz noise bandwidth?

Select	Answer
A	-148 dBm
B	-155 dBm
C	-174 dBm
D	-164 dBm

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	Neutralization
C	Amplifier desensitization
D	Adjacent channel interference

20. - E4E08

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

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

21. - E5A16

What is the resonant frequency of an RLC circuit if R is 33 ohms, L is 50 microhenries and C is 10 picofarads?

Select	Answer
A	7.12 MHz
B	23.5 MHz
C	23.5 kHz
D	7.12 kHz

22. - E5B03

How is impedance in polar form converted to an equivalent admittance?

Select	Answer
A	Take the reciprocal of the magnitude and change the sign of the angle
B	Take the square root of the magnitude and add 180 degrees to the angle
C	Square the magnitude and subtract 90 degrees from the angle
D	Take the reciprocal of the angle and change the sign of the magnitude

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 4
B	Point 5
C	Point 2
D	Point 6

24. - E5D12

How many watts are consumed in a circuit having a power factor of 0.2 if the input is 100 VAC at 4 amperes?

Select	Answer
A	80 watts
B	50 watts
C	2000 watts
D	400 watts

25. - E6A07

Which of the following indicates that a silicon NPN junction transistor is biased on?

Select	Answer
A	Base-to-emitter resistance of approximately 0.6 to 0.7 ohms
B	Base-to-emitter resistance of approximately 6 to 7 ohms
C	Base-to-emitter voltage of approximately 6 to 7 volts
D	Base-to-emitter voltage of approximately 0.6 to 0.7 volts

26. - E6B07

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

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

27. - E6C08

In Figure E6-3, what is the schematic symbol for a NAND gate?

Select	Answer
A	1
B	4
C	2
D	3

28. - E6D01

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

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

29. - E6E01

Why is gallium arsenide (GaAs) useful for semiconductor devices operating at UHF and higher frequencies?

Select	Answer
A	Lower transconductance
B	Higher noise figures
C	Lower junction voltage drop
D	Higher electron mobility

30. - E6F03

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

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

31. - E7A11

What type of logic defines "1" as a high voltage?

Select	Answer
A	Positive Logic
B	Assertive Logic
C	Negative logic
D	Reverse Logic

32. - E7B10

In Figure E7-1, what is the purpose of R1 and R2?

Select	Answer
A	Feedback
B	Load resistors
C	Self bias
D	Voltage divider bias

33. - E7C05

Which filter type is described as having ripple in the passband and a sharp cutoff?

Select	Answer
A	A Chebyshev filter
B	A passive op-amp filter
C	An active LC filter
D	A Butterworth filter

34. - E7D01

How does a linear electronic voltage regulator work?

Select	Answer
A	It has a ramp voltage as its output
B	It eliminates the need for a pass transistor
C	The control element duty cycle is proportional to the line or load conditions
D	The conduction of a control element is varied to maintain a constant output voltage

35. - E7E04

What is one way a single-sideband phone signal can be generated?

Select	Answer
A	By driving a product detector with a DSB signal
B	By using a reactance modulator followed by a mixer
C	By using a loop modulator followed by a mixer
D	By using a balanced modulator followed by a filter

36. - E7F08

What is the function of decimation?

Select	Answer
A	Reducing the effective sample rate by removing samples
B	Converting data to binary code decimal form
C	Attenuating the signal
D	Removing unnecessary significant digits

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

38. - E7H09

What type of frequency synthesizer circuit uses a phase accumulator, lookup table, digital to analog converter, and a low-pass anti-alias filter?

Select	Answer
A	A phase-locked loop synthesizer
B	A direct digital synthesizer
C	A diode-switching matrix synthesizer
D	A hybrid synthesizer

39. - E8A06

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

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

40. - E8B02

How does the modulation index of a phase-modulated emission vary with RF carrier frequency?

Select	Answer
A	It increases as the RF carrier frequency increases
B	It varies with the square root of the RF carrier frequency
C	It decreases as the RF carrier frequency increases
D	It does not depend on the RF carrier 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. - E8D10

What are some of the differences between the Baudot digital code and ASCII?

Select	Answer
A	Baudot uses 6 data bits per character, ASCII uses 7 or 8; Baudot has no letters/figures shift code, ASCII uses 2 letters/figures shift codes
B	Baudot uses 4 data bits per character, ASCII uses 7 or 8; Baudot uses 1 character as a letters/figures shift code, ASCII has no letters/figures code
C	Baudot uses 7 data bits per character, ASCII uses 8; Baudot has no letters/figures shift code, ASCII uses 2 letters/figures shift codes
D	Baudot uses 5 data bits per character, ASCII uses 7 or 8; Baudot uses 2 characters as letters/figures shift codes, ASCII has no letters/figures shift code

43. - E9A09

What is antenna efficiency?

Select	Answer
A	Effective radiated power divided by transmitter output
B	Radiation resistance divided by total resistance
C	Radiation resistance divided by transmission resistance
D	Total resistance divided by radiation resistance

44. - E9B04

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

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

45. - E9C12

Which of the following describes an Extended Double Zepp antenna?

Select	Answer
A	An end-fed folded dipole antenna
B	A wideband vertical antenna constructed from precisely tapered aluminum tubing
C	A center-fed 1.25-wavelength antenna (two 5/8-wave elements in phase)
D	A portable antenna erected using two push support poles

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

47. - E9E05

How must an antenna's driven element be tuned to use a hairpin matching system?

Select	Answer
A	The driven element reactance must be capacitive
B	The driven element resonance must be lower than the operating frequency
C	The driven element reactance must be inductive
D	The driven element radiation resistance must be higher than the characteristic impedance of the transmission line

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	The same as the characteristic impedance of the line
B	The same as the input impedance to the generator
C	Very low impedance
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 current axis
C	The voltage axis
D	The resistance axis

50. - E9H02

Which is generally true for low band (160 meter and 80 meter) receiving antennas?

Select	Answer
A	Low loss coax transmission line is essential for good performance
B	They must be erected at least 1/2 wavelength above the ground to attain good directivity
C	All these choices are correct
D	Atmospheric noise is so high that gain over a dipole is not important

Figure E5-1

Figure E6-3

Figure E7-1

Figure E9-3