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

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1. - E0A01

What is the primary function of an external earth connection or ground rod?

Select	Answer
A	Reduce RFI to telephones and home entertainment systems
B	Lightning protection
C	Reduce received noise
D	Reduce RF current flow between pieces of equipment

2. - E1A11

Which of the following describes authorization or licensing required when operating an amateur station aboard a U.S.-registered vessel in international waters?

Select	Answer
A	Any FCC-issued amateur license
B	An unrestricted Radiotelephone Operator Permit
C	Only General Class or higher amateur licenses
D	Any amateur license with an FCC Marine or Aircraft endorsement

3. - E1B10

What frequencies are authorized to an amateur station operating under RACES rules?

Select	Answer
A	Specific local government channels
B	Military Auxiliary Radio System (MARS) channels
C	All amateur service frequencies authorized to the control operator
D	Specific segments in the amateur service MF, HF, VHF and UHF bands

4. - E1C05

When may an automatically controlled station originate third party communications?

Select	Answer
A	When agreed upon by the sending or receiving station
B	Only when transmitting RTTY or data emissions
C	Never
D	When approved by the National Telecommunication and Information Administration

5. - E1D04

Which of the following is required in the identification transmissions from a balloon-borne telemetry station?

Select	Answer
A	The station's six-character Maidenhead grid locator
B	All these choices are correct
C	The output power of the balloon transmitter
D	Call sign

6. - E1E12

What must the VE team do with the application form if the examinee does not pass the exam?

Select	Answer
A	Maintain the application form with the VEC's records
B	Send the application form to the FCC and inform the FCC of the grade
C	Destroy the application form
D	Return the application document to the examinee

7. - E1F08

Which of the following types of amateur station communications are prohibited?

Select	Answer
A	Communications that have religious content
B	Communications in a language other than English
C	Communications that have political content, except as allowed by the Fairness Doctrine
D	Communications transmitted for hire or material compensation, except as otherwise provided in the rules

8. - E2A10

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

Select	Answer
A	HEO
B	Geomagnetic
C	LEO
D	Geostationary

9. - E2B12

What signals SSTV receiving software to begin a new picture line?

Select	Answer
A	Specific tone amplitudes
B	A two-tone signal
C	Specific tone frequencies
D	Elapsed time

10. - E2C10

Why might a DX station state that they are listening on another frequency?

Select	Answer
A	To separate the calling stations from the DX station
B	Because the DX station may be transmitting on a frequency that is prohibited to some responding stations
C	All these choices are correct
D	To improve operating efficiency by reducing interference

11. - E2D09

What type of modulation is used for JT65 contacts?

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

12. - E2E04

What is indicated when one of the ellipses in an FSK crossed-ellipse display suddenly disappears?

Select	Answer
A	The mark and space signal have been inverted
B	The receiver has drifted 5 kHz from the desired receive frequency
C	Selective fading has occurred
D	One of the signal filters is saturated

13. - E3A02

What characterizes libration fading of an EME signal?

Select	Answer
A	A gradual loss of signal as the sun rises
B	The returning echo is several hertz lower in frequency than the transmitted signal
C	A fluttery irregular fading
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	1000 miles
B	2500 miles
C	7500 miles
D	5000 miles

15. - E3C13

What type of polarization is best for ground-wave propagation?

Select	Answer
A	Circular
B	Horizontal
C	Elliptical
D	Vertical

16. - E4A04

How is the compensation of an oscilloscope probe typically adjusted?

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

17. - E4B09

What is indicated if the current reading on an RF ammeter placed in series with the antenna feed line of a transmitter increases as the transmitter is tuned to resonance?

Select	Answer
A	The transmitter is not properly neutralized
B	There is an impedance mismatch between the antenna and feed line
C	There is more power going into the antenna
D	There is possibly a short to ground in the feed line

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	-164 dBm
B	-148 dBm
C	-155 dBm
D	-174 dBm

19. - E4D02

Which of the following describes problems caused by poor dynamic range in a receiver?

Select	Answer
A	Oscillator instability and severe audio distortion of all but the strongest received signals
B	Oscillator instability requiring frequent retuning and loss of ability to recover the opposite sideband
C	Spurious signals caused by cross-modulation and desensitization from strong adjacent signals
D	Cross-modulation of the desired signal and insufficient audio power to operate the speaker

20. - E4E06

What is one type of electrical interference that might be caused by a nearby personal computer?

Select	Answer
A	A clicking noise at intervals of a few seconds
B	The appearance of unstable modulated or unmodulated signals at specific frequencies
C	A whining type noise that continually pulses off and on
D	A loud AC hum in the audio output of your station receiver

21. - E5A07

What is the magnitude of the current at the input of a parallel RLC circuit at resonance?

Select	Answer
A	R/L
B	Minimum
C	L/R
D	Maximum

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

23. - E5C08

What coordinate system is often used to display the phase angle of a circuit containing resistance, inductive and/or capacitive reactance?

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

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	2000 watts
C	400 watts
D	50 watts

25. - E6A11

In Figure E6-1, what is the schematic symbol for a P-channel junction FET?

Select	Answer
A	3
B	2
C	6
D	1

26. - E6B10

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

Select	Answer
A	6
B	1
C	5
D	7

27. - E6C01

What is the function of hysteresis in a comparator?

Select	Answer
A	To cause the output to change states continually
B	To allow the comparator to be used with AC input signals
C	To increase the sensitivity
D	To prevent input noise from causing unstable output signals

28. - E6D08

What is one reason for using powdered-iron cores rather than ferrite cores in an inductor?

Select	Answer
A	Powdered-iron cores generally require fewer turns to produce a given inductance
B	Powdered-iron cores generally maintain their characteristics at higher currents
C	Powdered-iron cores generally have greater initial permeability
D	Powdered-iron cores use smaller diameter wire for the same inductance

29. - E6E08

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

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

30. - E6F08

Why are optoisolators often used in conjunction with solid-state circuits when switching 120 VAC?

Select	Answer
A	Optoisolators provide a low impedance link between a control circuit and a power circuit
B	Optoisolators provide a very high degree of electrical isolation between a control circuit and the circuit being switched
C	Optoisolators provide impedance matching between the control circuit and power circuit
D	Optoisolators eliminate the effects of reflected light in the control circuit

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 switches momentarily to the opposite binary state and then returns to its original state after a set time
D	It maintains a constant output voltage, regardless of variations in the input voltage

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. - E7C09

What is a crystal lattice filter?

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

34. - E7D13

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

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

35. - E7E10

How does a diode envelope detector function?

Select	Answer
A	By rectification and filtering of RF signals
B	By mixing signals with noise in the transition region of the diode
C	By sensing the change of reactance in the diode with respect to frequency
D	By breakdown of the Zener voltage

36. - E7F10

What aspect of receiver analog-to-digital conversion determines the maximum receive bandwidth of a Direct Digital Conversion SDR?

Select	Answer
A	Processor latency
B	Sample width in bits
C	Sample clock phase noise
D	Sample rate

37. - E7G10

What absolute voltage gain can be expected from the circuit in Figure E7-3 when R1 is 1800 ohms and RF is 68 kilohms?

Select	Answer
A	1
B	38
C	76
D	0.03

38. - E7H12

Which of the following must be done to ensure that a crystal oscillator provides the frequency specified by the crystal manufacturer?

Select	Answer
A	Provide the crystal with a specified parallel capacitance
B	Provide the crystal with a specified parallel inductance
C	Bias the crystal at a specified current
D	Bias the crystal at a specified voltage

39. - E8A08

Why would a direct or flash conversion analog-to-digital converter be useful for a software defined radio?

Select	Answer
A	Very low power consumption decreases frequency drift
B	All these choices are correct
C	Immunity to out-of-sequence coding reduces spurious responses
D	Very high speed allows digitizing high frequencies

40. - E8B05

What is the deviation ratio of an FM-phone signal having a maximum frequency swing of plus-or-minus 5 kHz when the maximum modulation frequency is 3 kHz?

Select	Answer
A	0.6
B	1.67
C	0.167
D	60

41. - E8C09

Which digital code allows only one bit to change between sequential code values?

Select	Answer
A	Binary Coded Decimal Code
B	Extended Binary Coded Decimal Interchange Code
C	Gray code
D	Excess 3 code

42. - E8D02

What spread spectrum communications technique uses a high-speed binary bit stream to shift the phase of an RF carrier?

Select	Answer
A	Phase compandored spread spectrum
B	Frequency hopping
C	Direct sequence
D	Binary phase-shift keying

43. - E9A06

What is the effective radiated power relative to a dipole of a repeater station with 200 watts transmitter power output, 4 dB feed line loss, 3.2 dB duplexer loss, 0.8 dB circulator loss, and 10 dBd antenna gain?

Select	Answer
A	126 watts
B	2000 watts
C	300 watts
D	317 watts

44. - E9B01

In the antenna radiation pattern shown in Figure E9-1, what is the beamwidth?

Select	Answer
A	25 degrees
B	75 degrees
C	30 degrees
D	50 degrees

45. - E9C02

What is the radiation pattern of two 1/4-wavelength vertical antennas spaced 1/4 wavelength apart and fed 90 degrees out of phase?

Select	Answer
A	Cardioid
B	A figure-8 broadside to the axis of the array
C	Omni-directional
D	A figure-8 end-fire along 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	Solid wire
B	Wide flat copper strap
C	Resistive wire, such as spark plug wire
D	Stranded wire

47. - E9E07

What parameter describes the interactions at the load end of a mismatched transmission line?

Select	Answer
A	Dielectric constant
B	Velocity factor
C	Characteristic impedance
D	Reflection coefficient

48. - E9F01

What is the velocity factor of a transmission line?

Select	Answer
A	The index of shielding for coaxial cable
B	The velocity of the wave in the transmission line multiplied by the velocity of light in a vacuum
C	The ratio of the characteristic impedance of the line to the terminating impedance
D	The velocity of the wave in the transmission line divided by the velocity of light in a vacuum

49. - E9G01

Which of the following can be calculated using a Smith chart?

Select	Answer
A	Antenna radiation pattern
B	Radiation resistance
C	Radio propagation
D	Impedance along transmission lines

50. - E9H10

How can the output voltage of a multiple-turn receiving loop antenna be increased?

Select	Answer
A	By increasing the number of turns and/or the area
B	By winding adjacent turns in opposing directions
C	By reducing the permeability of the loop shield
D	By utilizing high impedance wire for the coupling loop

Figure E6-1

Figure E6-2

Figure E7-3

Figure E9-1