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	30 to 300 MHz
D	3 to 30 MHz

2. - E1A14

Except in some parts of Alaska, what is the maximum power permitted on the 630 meter band?

Select	Answer
A	50 watts PEP
B	5 watts EIRP
C	100 watts PEP
D	1 watt EIRP

3. - E1B04

What must be done before placing an amateur station within an officially designated wilderness area or wildlife preserve, or an area listed in the National Register of Historic Places?

Select	Answer
A	An Environmental Assessment must be submitted to the FCC
B	A proposal must be submitted to the National Park Service
C	A form FSD-15 must be submitted to the Department of the Interior
D	A letter of intent must be filed with the Environmental Protection Agency

4. - E1C05

When may an automatically controlled station originate third party communications?

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

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

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 submit the documents to the coordinating VEC for grading
B	They must submit the application document to the coordinating VEC according to the coordinating VEC instructions
C	They must collect and send the documents to the NCVEC for grading
D	They must collect and send the documents to the FCC according to 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	It was purchased in used condition from an amateur operator and is sold to another amateur operator for use at that operator's station
B	It was imported from a manufacturer in a country that does not require certification of RF power amplifiers
C	The equipment dealer assembled it from a kit
D	It was imported from a manufacturer in another country and was certificated by that country's government

8. - E2A07

Which of the following types of signals can be relayed through a linear transponder?

Select	Answer
A	PSK and packet
B	FM and CW
C	SSB and SSTV
D	All these choices are correct

9. - E2B01

How many times per second is a new frame transmitted in a fast-scan (NTSC) television system?

Select	Answer
A	30
B	120
C	60
D	90

10. - E2C07

What is the Cabrillo format?

Select	Answer
A	A standard for submission of electronic contest logs
B	The most common set of contest rules
C	A method of exchanging information during a contest QSO
D	The rules of order for meetings between contest sponsors

11. - E2D09

What type of modulation is used for JT65 contacts?

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

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	Direct FSK can transmit faster baud rates
D	Only direct FSK can be decoded by computer

13. - E3A02

What characterizes libration fading of an EME signal?

Select	Answer
A	The returning echo is several hertz lower in frequency than the transmitted signal
B	A gradual loss of signal as the sun rises
C	A slow change in the pitch of the CW signal
D	A fluttery irregular fading

14. - E3B05

Which amateur bands typically support long-path propagation?

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

15. - E3C04

What does the value of Bz (B sub Z) represent?

Select	Answer
A	Geomagnetic field stability
B	Critical frequency for vertical transmissions
C	Duration of long-delayed echoes
D	Direction and strength of the interplanetary magnetic field

16. - E4A06

What is the effect of aliasing on a digital oscilloscope caused by setting the time base too slow?

Select	Answer
A	Calibration of the vertical scale is no longer valid
B	A false, jittery low-frequency version of the signal is displayed
C	Excessive blanking occurs, which prevents display of the signal
D	All signals will have a DC offset

17. - E4B11

Which of the following can be measured with a vector network analyzer?

Select	Answer
A	Reflection coefficient
B	All these choices are correct
C	Output impedance
D	Input impedance

18. - E4C11

Why can an attenuator be used to reduce receiver overload on the lower frequency HF bands with little or no impact on signal-to-noise ratio?

Select	Answer
A	Signals are attenuated separately from the noise
B	Atmospheric noise is generally greater than internally generated noise even after attenuation
C	The attenuator has a noise filter to suppress interference
D	The attenuator has a low-pass filter to increase the strength of lower frequency signals

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. - E4E07

Which of the following can cause shielded cables to radiate or receive interference?

Select	Answer
A	Low inductance ground connections at both ends of the shield
B	Common-mode currents on the shield and conductors
C	Tying all ground connections to a common point resulting in differential-mode currents in the shield
D	Use of braided shielding material

21. - E5A12

What is the half-power bandwidth of a resonant circuit that has a resonant frequency of 3.7 MHz and a Q of 118?

Select	Answer
A	15.7 kHz
B	218.3 kHz
C	31.4 kHz
D	436.6 kHz

22. - E5B06

What is susceptance?

Select	Answer
A	The imaginary part of admittance
B	The magnetic impedance of a circuit
C	The ratio of magnetic field to electric field
D	A measure of the efficiency of a transformer

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 magnitude and the Y axis represents the phase angle
C	The X axis represents the reactive component and the Y axis represents the resistive component
D	The X axis represents the resistive component and the Y axis represents the reactive component

24. - E5D09

What happens to reactive power in an AC circuit that has both ideal inductors and ideal capacitors?

Select	Answer
A	It is dissipated in the formation of inductive and capacitive fields
B	It is dissipated as heat in the circuit
C	It is repeatedly exchanged between the associated magnetic and electric fields, but is not dissipated
D	It is dissipated as kinetic energy in the circuit

25. - E6A01

In what application is gallium arsenide used as a semiconductor material?

Select	Answer
A	In high-power audio circuits
B	In very low-frequency RF circuits
C	In high-current rectifier circuits
D	In microwave circuits

26. - E6B06

Which of the following is a common use of a Schottky diode?

Select	Answer
A	As a variable capacitance in an automatic frequency control circuit
B	As a rectifier in high current power supplies
C	As a VHF/UHF mixer or detector
D	As a constant voltage reference in a power supply

27. - E6C08

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

Select	Answer
A	3
B	2
C	4
D	1

28. - E6D06

What core material property determines the inductance of an inductor?

Select	Answer
A	Thermal impedance
B	Reactivity
C	Permeability
D	Resistance

29. - E6E06

What characteristics of the MMIC make it a popular choice for VHF through microwave circuits?

Select	Answer
A	The ability to retrieve information from a single signal even in the presence of other strong signals
B	Controlled gain, low noise figure, and constant input and output impedance over the specified frequency range
C	Nearly infinite gain, very high input impedance, and very low output impedance
D	Plate current that is controlled by a control grid

30. - E6F06

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

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

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 if only one input is 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 only if all inputs are logic 1

32. - E7B12

What type of amplifier circuit is shown in Figure E7-1?

Select	Answer
A	Common base
B	Emitter follower
C	Common emitter
D	Common collector

33. - E7C10

Which of the following filters would be the best choice for use in a 2 meter band repeater duplexer?

Select	Answer
A	A crystal filter
B	A cavity filter
C	A DSP filter
D	An L-C filter

34. - E7D12

What is the dropout voltage of an analog voltage regulator?

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

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. - E7F04

What is a common method of generating an SSB signal using digital signal processing?

Select	Answer
A	Mixing products are converted to voltages and subtracted by adder circuits
B	A frequency synthesizer removes the unwanted sidebands
C	Signals are combined in quadrature phase relationship
D	Varying quartz crystal characteristics emulated in digital form

37. - E7G11

What absolute voltage gain can be expected from the circuit in Figure E7-3 when R1 is 3300 ohms and RF is 47 kilohms?

Select	Answer
A	28
B	7
C	0.07
D	14

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

39. - 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	Lower the input bandwidth to increase the effective resolution
C	Remove harmonics from the output caused by the discrete analog levels generated
D	All these choices are correct

40. - E8B08

What describes Orthogonal Frequency Division Multiplexing?

Select	Answer
A	A digital mode for narrow-band, slow-speed transmissions
B	A digital modulation technique using subcarriers at frequencies chosen to avoid intersymbol interference
C	A bandwidth compression technique using Fourier transforms
D	A frequency modulation technique that uses non-harmonically related frequencies

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	If errors are detected, redundant data is substituted
D	Special polynomial codes provide automatic correction

42. - E8D11

What is one advantage of using ASCII code for data communications?

Select	Answer
A	It includes built-in error correction features
B	It uses one character as a shift code to send numeric and special characters
C	It contains fewer information bits per character than any other code
D	It is possible to transmit both upper and lower case text

43. - E9A08

What is antenna bandwidth?

Select	Answer
A	The frequency range over which an antenna satisfies a performance requirement
B	The angle formed between two imaginary lines drawn through the element ends
C	Antenna length divided by the number of elements
D	The angle between the half-power radiation points

44. - E9B07

How does the total amount of radiation emitted by a directional gain antenna compare with the total amount of radiation emitted from a theoretical isotropic antenna, assuming each is driven by the same amount of power?

Select	Answer
A	The total amount of radiation from the directional antenna is stronger by its front-to-back ratio
B	The radiation from the isotropic antenna is 2.15 dB stronger than that from the directional antenna
C	The total amount of radiation from the directional antenna is increased by the gain of the antenna
D	They are the same

45. - E9C10

Which of the following describes a Zepp antenna?

Select	Answer
A	A dipole constructed from zip cord
B	A vertical array capable of quickly changing the direction of maximum radiation by changing phasing lines
C	An omni-directional antenna commonly used for satellite communications
D	An end-fed dipole antenna

46. - E9D07

What is an advantage of using top loading in a shortened HF vertical antenna?

Select	Answer
A	Lower Q
B	Greater structural strength
C	Higher losses
D	Improved radiation efficiency

47. - E9E02

What is the name of an antenna matching system that matches an unbalanced feed line to an antenna by feeding the driven element both at the center of the element and at a fraction of a wavelength to one side of center?

Select	Answer
A	The gamma match
B	The stub match
C	The delta match
D	The epsilon 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	A capacitive reactance
B	The same as the characteristic impedance of the line
C	Zero
D	An inductive reactance

49. - E9G11

How are the wavelength scales on a Smith chart calibrated?

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

50. - E9H01

When constructing a Beverage antenna, which of the following factors should be included in the design to achieve good performance at the desired frequency?

Select	Answer
A	It must be mounted more than 1 wavelength above ground
B	Its overall length must not exceed 1/4 wavelength
C	It should be one or more wavelengths long
D	It should be configured as a four-sided loop

Figure E6-3

Figure E7-1

Figure E7-3