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

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1. - E0A03

Over what range of frequencies are the FCC human body RF exposure limits most restrictive?

Select	Answer
A	300 kHz to 3 MHz
B	300 to 3000 MHz
C	3 to 30 MHz
D	30 to 300 MHz

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	Only General Class or higher amateur licenses
B	Any FCC-issued amateur license
C	An unrestricted Radiotelephone Operator Permit
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 segments in the amateur service MF, HF, VHF and UHF bands
B	All amateur service frequencies authorized to the control operator
C	Specific local government channels
D	Military Auxiliary Radio System (MARS) channels

4. - E1C07

At what level below a signal's mean power level is its bandwidth determined according to FCC rules?

Select	Answer
A	3 dB
B	26 dB
C	23 dB
D	6 dB

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

6. - E1E05

What is the minimum passing score on all amateur operator license examinations?

Select	Answer
A	Minimum passing score of 70%
B	Minimum passing score of 80%
C	Minimum passing score of 77%
D	Minimum passing score of 74%

7. - E1F10

Who may be the control operator of an auxiliary station?

Select	Answer
A	Only Amateur Extra Class operators
B	Only General, Advanced or Amateur Extra Class operators
C	Only Technician, General, Advanced or Amateur Extra Class operators
D	Any licensed amateur operator

8. - E2A04

What is meant by the term mode? as applied to an amateur radio satellite?

Select	Answer
A	The satellite's uplink and downlink frequency bands
B	The satellite's orientation with respect to the Earth
C	Whether the satellite is in a low earth or geostationary orbit
D	Whether the satellite is in a polar or equatorial orbit

9. - E2B10

What aspect of an analog slow-scan television signal encodes the brightness of the picture?

Select	Answer
A	Tone frequency
B	Tone amplitude
C	Sync amplitude
D	Sync frequency

10. - E2C10

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

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

11. - E2D04

What technology is used to track, in real time, balloons carrying amateur radio transmitters?

Select	Answer
A	Bandwidth compressed LORAN
B	APRS
C	Doppler shift of beacon signals
D	Ultrasonics

12. - E2E01

Which of the following types of modulation is common for data emissions below 30 MHz?

Select	Answer
A	Spread spectrum
B	FSK
C	Pulse modulation
D	DTMF tones modulating an FM signal

13. - E3A05

Tropospheric propagation of microwave signals often occurs in association with what phenomenon?

Select	Answer
A	Sprites and jets
B	Grayline
C	Warm and cold fronts
D	Lightning discharges

14. - E3B05

Which amateur bands typically support long-path propagation?

Select	Answer
A	160 meters to 10 meters
B	Only 160 meters to 40 meters
C	Only 30 meters to 10 meters
D	6 meters to 2 meters

15. - E3C14

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

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

16. - E4A04

How is the compensation of an oscilloscope probe typically adjusted?

Select	Answer
A	A frequency standard is displayed and the probe is adjusted until the deflection time is accurate
B	A square wave is displayed and the probe is adjusted until the horizontal portions of the displayed wave are as nearly flat as possible
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. - E4B08

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

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

18. - E4C05

What does a receiver noise floor of -174 dBm represent?

Select	Answer
A	The minimum detectable signal as a function of receive frequency
B	The noise figure of a 1 Hz bandwidth receiver
C	The galactic noise contribution to minimum detectable signal
D	The theoretical noise in a 1 Hz bandwidth at the input of a perfect receiver at room temperature

19. - E4D02

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

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

20. - E4E01

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

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

21. - E5A03

What is the magnitude of the impedance of a series RLC circuit at resonance?

Select	Answer
A	Approximately equal to circuit resistance
B	Approximately equal to inductive reactance
C	Approximately equal to capacitive reactance
D	High, as compared to the circuit resistance

22. - E5B09

What is the relationship between the AC current through a capacitor and the voltage across a capacitor?

Select	Answer
A	Voltage and current are in phase
B	Voltage leads current by 90 degrees
C	Current leads voltage by 90 degrees
D	Voltage and current are 180 degrees out of phase

23. - E5C09

When using rectangular coordinates to graph the impedance of a circuit, what do the axes represent?

Select	Answer
A	The X axis represents the phase angle and the Y axis represents the magnitude
B	The X axis represents the resistive component and the Y axis represents the reactive component
C	The X axis represents the magnitude and the Y axis represents the phase angle
D	The X axis represents the reactive component and the Y axis represents the resistive component

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	1.42 mW
B	355 W
C	252 W
D	704 W

25. - E6A05

How does DC input impedance at the gate of a field-effect transistor compare with the DC input impedance of a bipolar transistor?

Select	Answer
A	They are both low impedance
B	An FET has higher input impedance
C	An FET has lower input impedance
D	They are both high impedance

26. - E6B10

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

Select	Answer
A	1
B	7
C	6
D	5

27. - E6C08

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

Select	Answer
A	3
B	4
C	2
D	1

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. - E6E09

Which of the following component package types would be most suitable for use at frequencies above the HF range?

Select	Answer
A	Axial lead
B	Surface mount
C	Radial lead
D	TO-220

30. - E6F06

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

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

31. - E7A09

What logical operation is performed by an exclusive NOR gate?

Select	Answer
A	It produces logic 0 at its output if only one input is logic 1
B	It produces logic 0 at its output only if all inputs are logic 0
C	It produces logic 1 at its output only if all inputs are logic 1
D	It produces logic 1 at its output if only one input is 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. - 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 gain of the RF stage preceding the filter
B	The amplitude of the signals passing through the filter
C	The relative frequencies of the individual crystals
D	The DC voltage applied to the quartz crystal

34. - E7D15

What is the purpose of a step-start circuit in a high-voltage power supply?

Select	Answer
A	To provide a dual-voltage output for reduced power applications
B	To allow the filter capacitors to charge gradually
C	To allow for remote control of the power supply
D	To compensate for variations of the incoming line voltage

35. - E7E07

What is meant by the term "baseband" in radio communications?

Select	Answer
A	The lowest frequency band that the transmitter or receiver covers
B	The unmodulated bandwidth of the transmitted signal
C	The frequency range occupied by a message signal prior to modulation
D	The basic oscillator frequency in an FM transmitter that is multiplied to increase the deviation and carrier frequency

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

37. - E7G12

What is an operational amplifier?

Select	Answer
A	A digital audio amplifier whose characteristics are determined by components external to the amplifier
B	A high-gain, direct-coupled differential amplifier with very high input impedance and very low output impedance
C	A RF amplifier used in the UHF and microwave regions
D	An amplifier used to increase the average output of frequency modulated amateur signals to the legal limit

38. - E7H03

How is positive feedback supplied in a Hartley oscillator?

Select	Answer
A	Through a tapped coil
B	Through a neutralizing capacitor
C	Through a capacitive divider
D	Through link coupling

39. - E8A05

What of the following instruments would be the most accurate for measuring the RMS voltage of a complex waveform?

Select	Answer
A	A grid dip meter
B	An absorption wave meter
C	A D'Arsonval meter
D	A true-RMS calculating meter

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. - E8C08

How does ARQ accomplish error correction?

Select	Answer
A	If errors are detected, a retransmission is requested
B	Special binary codes provide automatic correction
C	Special polynomial codes provide automatic correction
D	If errors are detected, redundant data is substituted

42. - E8D05

What is the most common method of reducing key clicks?

Select	Answer
A	Increase keying waveform rise and fall times
B	Reduce keying waveform rise and fall times
C	Low-pass filters at the transmitter output
D	High-pass filters at the transmitter output

43. - E9A03

What is the radiation resistance of an antenna?

Select	Answer
A	The value of a resistance that would dissipate the same amount of power as that radiated from an antenna
B	The specific impedance of the antenna
C	The resistance in the atmosphere that an antenna must overcome to be able to radiate a signal
D	The combined losses of the antenna elements and feed line

44. - E9B01

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

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

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 decreases in the downhill direction
B	The horizontal beamwidth increases in the uphill direction
C	The horizontal beamwidth decreases in the downhill direction
D	The main lobe takeoff angle increases in the downhill 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	All these choices are correct
B	Hairpin match
C	Double-bazooka match
D	Gamma match

48. - E9F10

What impedance does a 1/8-wavelength transmission line present to a generator when the line is shorted at the far end?

Select	Answer
A	The same as the characteristic impedance of the line
B	Zero
C	An inductive reactance
D	A capacitive reactance

49. - E9G01

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

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

50. - E9H03

What is Receiving Directivity Factor (RDF)?

Select	Answer
A	Forward gain compared to the gain in the reverse direction
B	Forward gain compared to average gain over the entire hemisphere
C	Relative directivity compared to a dipole
D	Relative directivity compared to isotropic

Figure E6-2

Figure E6-3

Figure E9-1