US Amateur Radio - Amateur Extra (Element 4, 2016-2020) Practice Test

Logging in (or registering) will help the system to select questions that you need to focus on.

1. - E1A13

Who must be in physical control of the station apparatus of an amateur station aboard any vessel or craft that is documented or registered in the United States?

Select	Answer
A	Any person holding an FCC issued amateur license or who is authorized for alien reciprocal operation
B	Only a person named in an amateur station license grant
C	Any person named in an amateur station license grant or a person holding an unrestricted Radiotelephone Operator Permit
D	Only a person with an FCC Marine Radio

2. - E1B02

Which of the following factors might cause the physical location of an amateur station apparatus or antenna structure to be restricted?

Select	Answer
A	The location is in an ITU Zone designated for coordination with one or more foreign governments
B	The location is near an area of political conflict
C	The location is of geographical or horticultural importance
D	The location is of environmental importance or significant in American history, architecture, or culture

3. - E1C09

Which of these ranges of frequencies is available for an automatically controlled repeater operating below 30 MHz?

Select	Answer
A	10.100 MHz - 10.150 MHz
B	24.940 MHz - 24.990 MHz
C	18.110 MHz - 18.168 MHz
D	29.500 MHz - 29.700 MHz

4. - E1D07

Which amateur service HF bands have frequencies authorized for space stations?

Select	Answer
A	Only the 40 m, 30 m, 20 m, 15 m, 12 m and 10 m bands
B	Only the 40 m, 20 m, 17 m, 15 m, 12 m and 10 m bands
C	All HF bands
D	Only the 40 m, 20 m, 17 m, 15 m and 10 m bands

5. - E1E07

What should a VE do if a candidate fails to comply with the examiner's instructions during an amateur operator license examination?

Select	Answer
A	Immediately terminate everyone's examination and close the session
B	Warn the candidate that continued failure to comply will result in termination of the examination
C	Immediately terminate the candidate's examination
D	Allow the candidate to complete the examination, but invalidate the results

6. - E1F02

What privileges are authorized in the U.S. to persons holding an amateur service license granted by the Government of Canada?

Select	Answer
A	None, they must obtain a U.S. license
B	The operating terms and conditions of the Canadian amateur service license, not to exceed U.S. Extra Class privileges
C	All privileges of the Extra Class license
D	Full privileges, up to and including those of the Extra Class License, on the 80, 40, 20, 15, and 10 meter bands

7. - E2A11

What type of antenna can be used to minimize the effects of spin modulation and Faraday rotation?

Select	Answer
A	An isotropic antenna
B	A log-periodic dipole array
C	A circularly polarized antenna
D	A linearly polarized antenna

8. - E2B16

Which is a video standard used by North American Fast Scan ATV stations?

Select	Answer
A	PAL
B	DRM
C	Scottie
D	NTSC

9. - E2C12

What might help to restore contact when DX signals become too weak to copy across an entire HF band a few hours after sunset?

Select	Answer
A	Wait 24 hours before attempting another communication on the band
B	Wait 90 minutes or so for the signal degradation to pass
C	Switch to a lower frequency HF band
D	Switch to a higher frequency HF band

10. - E2D05

Which of the following techniques is normally used by low Earth orbiting digital satellites to relay messages around the world?

Select	Answer
A	Digipeating
B	Multi-satellite relaying
C	Store-and-forward
D	Node hopping

11. - E2E06

What is the most common data rate used for HF packet?

Select	Answer
A	1200 baud
B	300 baud
C	48 baud
D	110 baud

12. - E3A06

Which of the following is required for microwave propagation via rain scatter?

Select	Answer
A	The rain must be within radio range of both stations
B	Rain droplets must be electrically charged
C	All of these choices are correct
D	Rain droplets must be within the E layer

13. - E3B10

What is the cause of gray-line propagation?

Select	Answer
A	At twilight and sunrise, D-layer absorption is low while E-layer and F-layer propagation remains high
B	At mid-afternoon, the Sun heats the ionosphere decreasing radio wave refraction and the MUF
C	At midday, the Sun super heats the ionosphere causing increased refraction of radio waves
D	In darkness, solar absorption drops greatly while atmospheric ionization remains steady

14. - E3C05

What orientation of Bz (B sub z) increases the likelihood that incoming particles from the Sun will cause disturbed conditions?

Select	Answer
A	Eastward
B	Southward
C	Northward
D	Westward

15. - E4A01

Which of the following parameter determines the bandwidth of a digital or computer-based oscilloscope?

Select	Answer
A	Input capacitance
B	Input impedance
C	Sampling rate
D	Sample resolution

16. - E4B14

What happens if a dip meter is too tightly coupled to a tuned circuit being checked?

Select	Answer
A	Harmonics are generated
B	Cross modulation occurs
C	Intermodulation distortion occurs
D	A less accurate reading results

17. - E4C05

What does a value of -174 dBm/Hz represent with regard to the noise floor of a receiver?

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 at the input of a perfect receiver at room temperature

18. - E4D09

What is the purpose of the preselector in a communications receiver?

Select	Answer
A	To increase rejection of unwanted signals
B	To provide a range of AGC time constants
C	To allow selection of the optimum RF amplifier device
D	To store often-used frequencies

19. - E4E13

What might be the cause of a loud roaring or buzzing AC line interference that comes and goes at intervals?

Select	Answer
A	All of these choices are correct
B	Arcing contacts in a thermostatically controlled device
C	A malfunctioning illuminated advertising display
D	A defective doorbell or doorbell transformer inside a nearby residence

20. - E5A01

What can cause the voltage across reactances in series to be larger than the voltage applied to them?

Select	Answer
A	Capacitance
B	Resistance
C	Conductance
D	Resonance

21. - E5B09

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

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

22. - E5C16

Which point on Figure E5-2 best represents the impedance of a series circuit consisting of a 300 ohm resistor and a 19 picofarad capacitor at 21.200 MHz?

Select	Answer
A	Point 3
B	Point 7
C	Point 8
D	Point 1

23. - 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	50 watts
B	400 watts
C	80 watts
D	2000 watts

24. - E6A05

What is the alpha of a bipolar junction transistor?

Select	Answer
A	The change of base current with respect to collector current
B	The change of collector current with respect to base current
C	The change of collector current with respect to gate current
D	The change of collector current with respect to emitter current

25. - E6B01

What is the most useful characteristic of a Zener diode?

Select	Answer
A	A constant voltage drop under conditions of varying current
B	A negative resistance region
C	A constant current drop under conditions of varying voltage
D	An internal capacitance that varies with the applied voltage

26. - E6C06

Why do CMOS digital integrated circuits have high immunity to noise on the input signal or power supply?

Select	Answer
A	The input switching threshold is about one-half the power supply voltage
B	Input signals are stronger
C	The input switching threshold is about two times the power supply voltage
D	Larger bypass capacitors are used in CMOS circuit design

27. - E6D10

What is a primary advantage of using a toroidal core instead of a solenoidal core in an inductor?

Select	Answer
A	Toroidal cores exhibit greater hysteresis
B	Toroidal cores make it easier to couple the magnetic energy into other components
C	Toroidal cores confine most of the magnetic field within the core material
D	Toroidal cores have lower Q characteristics

28. - E6E04

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

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

29. - E6F06

Which of these materials is affected the most by photoconductivity?

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

30. - E7A04

How many flip-flops are required to divide a signal frequency by 4?

Select	Answer
A	2
B	4
C	1
D	8

31. - E7B13

In Figure E7-2, what is the purpose of R?

Select	Answer
A	Collector load
B	Voltage regulation
C	Fixed bias
D	Emitter load

32. - E7C12

Which describes a Pi-L-network used for matching a vacuum tube final amplifier to a 50 ohm unbalanced output?

Select	Answer
A	A network with only three discrete parts
B	A Phase Inverter Load network
C	A Pi-network with an additional series inductor on the output
D	A matching network in which all components are isolated from ground

33. - E7D10

What is the primary reason that a high-frequency switching type high voltage power supply can be both less expensive and lighter in weight than a conventional power supply?

Select	Answer
A	The inverter design does not require any output filtering
B	It uses a diode bridge rectifier for increased output
C	It uses a large power factor compensation capacitor to create free power from the unused portion of the AC cycle
D	The high frequency inverter design uses much smaller transformers and filter components for an equivalent power output

34. - E7E04

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

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

35. - 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 the same rate as the highest frequency component of the signal
B	At half the rate of the highest frequency component of the signal
C	At twice the rate of the highest frequency component of the signal
D	At four times the rate of the highest frequency component of the signal

36. - E7G05

How can unwanted ringing and audio instability be prevented in a multi-section op-amp RC audio filter circuit?

Select	Answer
A	Restrict both gain and Q
B	Restrict Q but increase gain
C	Increase both gain and Q
D	Restrict gain but increase Q

37. - E7H10

What information is contained in the lookup table of a direct digital frequency synthesizer?

Select	Answer
A	The phase relationship between a reference oscillator and the output waveform
B	The amplitude values that represent a sine-wave output
C	The synthesizer frequency limits and frequency values stored in the radio memories
D	The phase relationship between a voltage-controlled oscillator and the output waveform

38. - E8A10

What is the purpose of a low pass filter used in conjunction with a digital-to-analog converter?

Select	Answer
A	Improve accuracy by removing out of sequence codes from the input
B	All of these choices are correct
C	Remove harmonics from the output caused by the discrete analog levels generated
D	Lower the input bandwidth to increase the effective resolution

39. - E8B02

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

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

40. - E8C07

What is the necessary bandwidth of a 4800-Hz frequency shift, 9600-baud ASCII FM transmission?

Select	Answer
A	4.8 kHz
B	5.76 kHz
C	15.36 kHz
D	9.6 kHz

41. - E8D12

What is the advantage of including a parity bit with an ASCII character stream?

Select	Answer
A	Some types of errors can be detected SUBELEMENT E9 - ANTENNAS AND TRANSMISSION LINES [8 Exam Questions - 8 Groups] E9A Basic Antenna parameters: radiation resistance, gain, beamwidth, efficiency, beamwidth; effective radiated power, polarization E9A01 (C) What describes an isotropic antenna? A. A grounded antenna used to measure earth conductivity B. A horizontally polarized antenna used to compare Yagi antennas C. A theoretical antenna used as a reference for antenna gain D. A spacecraft antenna used to direct signals toward the earth
B	Faster transmission rate
C	Foreign language characters can be sent
D	The signal can overpower interfering signals

42. - E9A05

What is included in the total resistance of an antenna system?

Select	Answer
A	Transmission-line resistance plus radiation resistance
B	Radiation resistance plus space impedance
C	Radiation resistance plus transmission resistance
D	Radiation resistance plus ohmic resistance

43. - E9B14

What type of information can be obtained by submitting the details of a proposed new antenna to a modeling program?

Select	Answer
A	SWR vs frequency charts
B	Antenna gain
C	Polar plots of the far field elevation and azimuth patterns
D	All of these choices are correct

44. - E9C07

What is the approximate feed point impedance at the center of a two-wire folded dipole antenna?

Select	Answer
A	450 ohms
B	72 ohms
C	50 ohms
D	300 ohms

45. - E9D09

What is the function of a loading coil used as part of an HF mobile antenna?

Select	Answer
A	To lower the Q
B	To lower the losses
C	To cancel capacitive reactance
D	To increase the SWR bandwidth

46. - 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

47. - E9F15

What impedance does a 1/2 wavelength transmission line present to a generator when the line is open at the far end?

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

48. - E9G11

How are the wavelength scales on a Smith chart calibrated?

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

49. - E9H02

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

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

50. - E0A06

Why are there separate electric (E) and magnetic (H) field MPE limits?

Select	Answer
A	Ground reflections and scattering make the field impedance vary with location
B	E field and H field radiation intensity peaks can occur at different locations
C	All of these choices are correct
D	The body reacts to electromagnetic radiation from both the E and H fields

Figure E5-2

Figure E7-2