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

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1. - E0A07

How may dangerous levels of carbon monoxide from an emergency generator be detected?

Select	Answer
A	Only with a carbon monoxide detector
B	Any ordinary smoke detector can be used
C	By the yellowish appearance of the gas
D	By the odor

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

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

4. - E1C06

Which of the following is required in order to operate in accordance with CEPT rules in foreign countries where permitted?

Select	Answer
A	You must bring a copy of FCC Public Notice DA 16-1048
B	The U.S. embassy must approve of your operation
C	You must append "/CEPT" to your call sign
D	You must identify in the official language of the country in which you are operating

5. - E1D08

Which VHF amateur bands have frequencies authorized for space stations?

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

6. - E1E10

What must the administering VEs do after the administration of a successful examination for an amateur operator license?

Select	Answer
A	They must collect and send the documents to the NCVEC for grading
B	They must collect and send the documents to the FCC according to instructions
C	They must collect and submit the documents to the coordinating VEC for grading
D	They must submit the application document to the coordinating VEC according to the coordinating VEC instructions

7. - E1F03

Under what circumstances may a dealer sell an external RF power amplifier capable of operation below 144 MHz if it has not been granted FCC certification?

Select	Answer
A	The equipment dealer assembled it from a kit
B	It was imported from a manufacturer in a country that does not require certification of RF power amplifiers
C	It was purchased in used condition from an amateur operator and is sold to another amateur operator for use at that operator's station
D	It was imported from a manufacturer in another country and was certificated by that country's government

8. - E2A04

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

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

9. - E2B02

How many horizontal lines make up a fast-scan (NTSC) television frame?

Select	Answer
A	1080
B	60
C	30
D	525

10. - E2C04

Which of the following frequencies are sometimes used for amateur radio mesh networks?

Select	Answer
A	Frequencies shared with various unlicensed wireless data services
B	Cable TV channels 41 through 43
C	HF frequencies where digital communications are permitted
D	The 60 meter band channel centered on 5373 kHz

11. - E2D05

What is one advantage of the JT65 mode?

Select	Answer
A	Permits fast-scan TV transmissions over narrow bandwidth
B	Easily copied by ear if necessary
C	The ability to decode signals which have a very low signal-to-noise ratio
D	Uses only a 65 Hz bandwidth

12. - E2E03

How is the timing of FT4 contacts organized?

Select	Answer
A	Stations take turns on alternate days
B	Alternating transmissions at 7.5 second intervals
C	It depends on the lunar phase
D	By exchanging ACK/NAK packets

13. - E3A06

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	Switch to a lower frequency HF band
C	Wait 90 minutes or so for the signal degradation to pass
D	Switch to a higher frequency HF band

14. - E3B07

What happens to linearly polarized radio waves that split into ordinary and extraordinary waves in the ionosphere?

Select	Answer
A	They are bent toward the magnetic poles
B	They become elliptically polarized
C	They become phase locked
D	They become depolarized

15. - E3C01

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

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

16. - E4A01

Which of the following limits the highest frequency signal that can be accurately displayed on a digital oscilloscope?

Select	Answer
A	All these choices are correct
B	Sampling rate of the analog-to-digital converter
C	Q of the circuit
D	Amount of memory

17. - E4B03

Which S parameter is equivalent to forward gain?

Select	Answer
A	S22
B	S21
C	S12
D	S11

18. - E4C02

Which of the following receiver circuits can be effective in eliminating interference from strong out-of-band signals?

Select	Answer
A	A narrow IF filter
B	A front-end filter or pre-selector
C	A properly adjusted product detector
D	A notch filter

19. - E4D09

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

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

20. - E4E02

Which of the following types of noise can often be reduced with a digital signal processing noise filter?

Select	Answer
A	Ignition noise
B	All these choices are correct
C	Power line noise
D	Broadband white noise

21. - E5A09

How is the Q of an RLC parallel resonant circuit calculated?

Select	Answer
A	Reactance of the inductance multiplied by the reactance of the capacitance
B	Reactance of either the inductance or capacitance divided by the resistance
C	Resistance divided by the reactance of either the inductance or capacitance
D	Reactance of either the inductance or capacitance multiplied by the resistance

22. - E5B12

What is admittance?

Select	Answer
A	The inverse of Q factor
B	The term for the gain of a field effect transistor
C	The inverse of impedance
D	The turns ratio of a transformer

23. - E5C06

What does the impedance 50-j25 represent?

Select	Answer
A	50 ohms resistance in series with 25 ohms capacitive reactance
B	50 ohms resistance in series with 25 ohms inductive reactance
C	25 ohms resistance in series with 50 ohms inductive reactance
D	25 ohms resistance in series with 50 ohms capacitive reactance

24. - E5D06

In what direction is the magnetic field oriented about a conductor in relation to the direction of electron flow?

Select	Answer
A	In the same direction as the current
B	In a circle around the conductor
C	In all directions; omni-directional
D	In a direction opposite to the current

25. - E6A12

Why do many MOSFET devices have internally connected Zener diodes on the gates?

Select	Answer
A	To protect the substrate from excessive voltages
B	To provide a voltage reference for the correct amount of reverse-bias gate voltage
C	To keep the gate voltage within specifications and prevent the device from overheating
D	To reduce the chance of static damage to the gate

26. - E6B03

What type of bias is required for an LED to emit light?

Select	Answer
A	Inductive bias
B	Zero bias
C	Reverse bias
D	Forward bias

27. - E6C04

Which of the following is an advantage of BiCMOS logic?

Select	Answer
A	It is immune to electrostatic damage
B	It has the high input impedance of CMOS and the low output impedance of bipolar transistors
C	Its simplicity results in much less expensive devices than standard CMOS
D	All these choices are correct

28. - E6D05

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

Select	Answer
A	Ferrite toroids are easier to use with surface mount technology
B	Ferrite toroids generally have better temperature stability
C	Ferrite toroids generally require fewer turns to produce a given inductance value
D	Ferrite toroids generally have lower initial permeability

29. - E6E12

Why are DIP through-hole package ICs not typically used at UHF and higher frequencies?

Select	Answer
A	Epoxy coating is conductive above 300 MHz
B	Too many pins
C	Excessive lead length
D	Unsuitable for combining analog and digital signals

30. - E6F03

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

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

31. - E7A09

What logical operation is performed by an exclusive NOR gate?

Select	Answer
A	It produces logic 0 at its output only if all inputs are logic 0
B	It produces logic 1 at its output only if all inputs are logic 1
C	It produces logic 0 at its output if only one input is logic 1
D	It produces logic 1 at its output if only one input is logic 1

32. - E7B07

Which of the following is a likely result when a Class C amplifier is used to amplify a single-sideband phone signal?

Select	Answer
A	Signal distortion and excessive bandwidth
B	Reduced intermodulation products
C	Signal inversion
D	Increased overall intelligibility

33. - E7C11

Which of the following describes a receiving filter's ability to reject signals occupying an adjacent channel?

Select	Answer
A	Passband ripple
B	Noise factor
C	Phase response
D	Shape factor

34. - E7D12

What is the dropout voltage of an analog voltage regulator?

Select	Answer
A	Minimum input voltage for rated power dissipation
B	Maximum that the output voltage may decrease at rated load
C	Maximum output voltage drops when the input voltage is varied over its specified range
D	Minimum input-to-output voltage required to maintain regulation

35. - E7E03

What is a frequency discriminator stage in a FM receiver?

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

36. - E7F14

Which of the following would allow a digital signal processing filter to create a sharper filter response?

Select	Answer
A	Higher data rate
B	Double-precision math routines
C	More taps
D	Complex phasor representations

37. - E7G03

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

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

38. - E7H15

Which of these functions can be performed by a phase-locked loop?

Select	Answer
A	Frequency synthesis, FM demodulation
B	Wide-band AF and RF power amplification
C	Photovoltaic conversion, optical coupling
D	Comparison of two digital input signals, digital pulse counter

39. - E8A03

What type of wave does a Fourier analysis show to be made up of sine waves of a given fundamental frequency plus all its harmonics?

Select	Answer
A	A cosine wave
B	A sawtooth wave
C	A square wave
D	A sine wave

40. - E8B06

What is the deviation ratio of an FM-phone signal having a maximum frequency swing of plus or minus 7.5 kHz when the maximum modulation frequency is 3.5 kHz?

Select	Answer
A	0.47
B	0.214
C	47
D	2.14

41. - E8C08

How does ARQ accomplish error correction?

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

42. - E8D03

How does the spread spectrum technique of frequency hopping work?

Select	Answer
A	A binary bit stream is used to shift the phase of an RF carrier very rapidly in a pseudorandom sequence
B	If interference is detected by the receiver it will signal the transmitter to wait until the frequency is clear
C	The frequency of the transmitted signal is changed very rapidly according to a pseudorandom sequence also used by the receiving station
D	If interference is detected by the receiver it will signal the transmitter to change frequencies

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	2000 watts
B	126 watts
C	300 watts
D	317 watts

44. - E9B05

What type of antenna pattern is shown in Figure E9-2?

Select	Answer
A	Azimuth
B	Radiation resistance
C	Elevation
D	Polarization

45. - E9C06

What is the effect of adding a terminating resistor to a rhombic antenna?

Select	Answer
A	It changes the radiation pattern from bidirectional to unidirectional
B	It decreases the ground loss
C	It reflects the standing waves on the antenna elements back to the transmitter
D	It changes the radiation pattern from horizontal to vertical polarization

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

47. - E9E06

Which of these feed line impedances would be suitable for constructing a quarter-wave Q-section for matching a 100-ohm loop to 50-ohm feed line?

Select	Answer
A	62 ohms
B	50 ohms
C	75 ohms
D	450 ohms

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	An inductive reactance
C	Zero
D	A capacitive reactance

49. - E9G10

What do the arcs on a Smith chart represent?

Select	Answer
A	SWR
B	Frequency
C	Points with constant reactance
D	Points with constant resistance

50. - E9H04

What is an advantage of placing a grounded electrostatic shield around a small loop direction-finding antenna?

Select	Answer
A	It eliminates unbalanced capacitive coupling to the surroundings, improving the nulls
B	It eliminates tracking errors caused by strong out-of-band signals
C	It adds capacitive loading, increasing the bandwidth of the antenna
D	It increases signal strength by providing a better match to the feed line

Figure E9-2