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

2. - E1A12

What special operating frequency restrictions are imposed on slow scan TV transmissions?

Select	Answer
A	They are restricted to phone band segments
B	They are not permitted above 54 MHz
C	None; they are allowed on all amateur frequencies
D	They are restricted to 7.245 MHz, 14.245 MHz, 21.345 MHz, and 28.945 MHz

3. - E1B07

To what type of regulations does PRB-1 apply?

Select	Answer
A	FAA tower height limits
B	State and local zoning
C	Use of wireless devices in vehicles
D	Homeowners associations

4. - E1C12

On what portion of the 630 meter band are phone emissions permitted?

Select	Answer
A	Only the top 3 kHz
B	The entire band
C	Only the bottom 3 kHz
D	None

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

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 FCC according to instructions
D	They must collect and send the documents to the NCVEC for grading

7. - E1F06

Under what circumstances might the FCC issue a Special Temporary Authority (STA) to an amateur station?

Select	Answer
A	To provide additional spectrum for personal use
B	To provide temporary operation while awaiting normal licensing
C	To provide for experimental amateur communications
D	To allow regular operation on Land Mobile channels

8. - E2A04

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

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

9. - E2B10

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

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

10. - E2C11

How should you generally identify your station when attempting to contact a DX station during a contest or in a pileup?

Select	Answer
A	Send your full call sign once or twice
B	Send only the last two letters of your call sign until you make contact
C	Send your full call sign and grid square
D	Send the call sign of the DX station three times, the words this is,then your call sign three times

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	Uses only a 65 Hz bandwidth
D	The ability to decode signals which have a very low signal-to-noise ratio

12. - E2E04

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

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

13. - E3A11

What is a typical range for tropospheric propagation of microwave signals?

Select	Answer
A	1200 miles
B	100 miles to 300 miles
C	2500 miles
D	10 miles to 50 miles

14. - E3B05

Which amateur bands typically support long-path propagation?

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

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. - E4A07

Which of the following is an advantage of using an antenna analyzer compared to an SWR bridge to measure antenna SWR?

Select	Answer
A	Antenna analyzers do not need an external RF source
B	All these choices are correct
C	Antenna analyzers display a time-varying representation of the modulation envelope
D	Antenna analyzers automatically tune your antenna for resonance

17. - E4B02

What is the significance of voltmeter sensitivity expressed in ohms per volt?

Select	Answer
A	The full scale reading of the voltmeter multiplied by its ohms per volt rating will indicate the input impedance of the voltmeter
B	When used as an ohmmeter, the reading in ohms divided by the ohms per volt rating will determine the voltage applied to the circuit
C	When used as an ammeter, the full scale reading in amps divided by ohms per volt rating will determine the size of shunt needed
D	When used as a galvanometer, the reading in volts multiplied by the ohms per volt rating will determine the power drawn by the device under test

18. - E4C09

Which of the following choices is a good reason for selecting a high frequency for the design of the IF in a superheterodyne HF or VHF communications receiver?

Select	Answer
A	Easier for front-end circuitry to eliminate image responses
B	Reduced drift
C	Fewer components in the receiver
D	Improved receiver noise figure

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	Spurious signals caused by cross-modulation and desensitization from strong adjacent signals
C	Cross-modulation of the desired signal and insufficient audio power to operate the speaker
D	Oscillator instability and severe audio distortion of all but the strongest received signals

20. - E4E03

Which of the following signals might a receiver noise blanker be able to remove from desired signals?

Select	Answer
A	Signals that have a sharply peaked frequency distribution
B	Signals that appear at one IF but not another
C	Signals that are constant at all IF levels
D	Signals that appear across a wide bandwidth

21. - E5A02

What is resonance in an LC or RLC circuit?

Select	Answer
A	The frequency at which the capacitive reactance equals the inductive reactance
B	The lowest frequency that will pass current
C	The frequency at which the reactive impedance equals the resistive impedance
D	The highest frequency that will pass current

22. - E5B12

What is admittance?

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

23. - E5C10

Which point on Figure E5-1 best represents the impedance of a series circuit consisting of a 400-ohm resistor and a 38-picofarad capacitor at 14 MHz?

Select	Answer
A	Point 2
B	Point 4
C	Point 5
D	Point 6

24. - E5D10

How can the true power be determined in an AC circuit where the voltage and current are out of phase?

Select	Answer
A	By dividing the apparent power by the power factor
B	By multiplying the reactive power by the power factor
C	By multiplying the apparent power by the power factor
D	By dividing the reactive power by the power factor

25. - E6A01

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

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

26. - E6B10

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

Select	Answer
A	6
B	7
C	1
D	5

27. - E6C03

What is tri-state logic?

Select	Answer
A	Low-power logic devices designed to operate at 3 volts
B	Logic devices that utilize ternary math
C	Proprietary logic devices manufactured by Tri-State Devices
D	Logic devices with 0, 1, and high-impedance output states

28. - E6D09

What devices are commonly used as VHF and UHF parasitic suppressors at the input and output terminals of a transistor HF amplifier?

Select	Answer
A	Butterworth filters
B	Ferrite beads
C	Electrolytic capacitors
D	Steel-core toroids

29. - E6E06

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

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

30. - E6F10

What is the most common type of photovoltaic cell used for electrical power generation?

Select	Answer
A	Copper oxide
B	Cadmium Sulfide
C	Selenium
D	Silicon

31. - E7A11

What type of logic defines "1" as a high voltage?

Select	Answer
A	Positive Logic
B	Assertive Logic
C	Negative logic
D	Reverse Logic

32. - E7B14

Why are switching amplifiers more efficient than linear amplifiers?

Select	Answer
A	Linear amplifiers have high gain resulting in higher harmonic content
B	Switching amplifiers operate at higher voltages
C	The power transistor is at saturation or cutoff most of the time
D	Switching amplifiers use push-pull circuits

33. - E7C04

How does an impedance-matching circuit transform a complex impedance to a resistive impedance?

Select	Answer
A	It cancels the reactive part of the impedance and changes the resistive part to a desired value
B	It introduces negative resistance to cancel the resistive part of impedance
C	It introduces transconductance to cancel the reactive part of impedance
D	Reactive currents are dissipated in matched resistances

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	Minimum input-to-output voltage required to maintain regulation
D	Maximum that the output voltage may decrease at rated load

35. - E7E03

What is a frequency discriminator stage in a FM receiver?

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

36. - E7F01

What is meant by direct digital conversion as applied to software defined radios?

Select	Answer
A	Software is converted from source code to object code during operation of the receiver
B	Incoming RF is digitized by an analog-to-digital converter without being mixed with a local oscillator signal
C	A switching mixer is used to generate I and Q signals directly from the RF input
D	Incoming RF is converted to a control voltage for a voltage controlled oscillator

37. - E7G04

What is meant by the "op-amp input offset voltage"?

Select	Answer
A	The potential between the amplifier input terminals of the op-amp in an open loop condition
B	The difference between the output voltage of the op-amp and the input voltage required in the immediately following stage
C	The output voltage of the op-amp minus its input voltage
D	The differential input voltage needed to bring the open loop output voltage to zero

38. - E7H10

What information is contained in the lookup table of a direct digital synthesizer (DDS)?

Select	Answer
A	Frequently used receiver and transmitter frequencies
B	The phase relationship between a reference oscillator and the output waveform
C	The phase relationship between a voltage-controlled oscillator and the output waveform
D	Amplitude values that represent the desired waveform

39. - E8A10

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

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

40. - E8B03

What is the modulation index of an FM-phone signal having a maximum frequency deviation of 3000 Hz either side of the carrier frequency when the modulating frequency is 1000 Hz?

Select	Answer
A	3
B	3000
C	0.3
D	1000

41. - E8C10

How may data rate be increased without increasing bandwidth?

Select	Answer
A	Increasing analog-to-digital conversion resolution
B	Using a more efficient digital code
C	Using forward error correction
D	It is impossible

42. - E8D07

What is a common cause of overmodulation of AFSK signals?

Select	Answer
A	Excessive numbers of retries
B	Bit errors in the modem
C	Excessive transmit audio levels
D	Ground loops

43. - E9A08

What is antenna bandwidth?

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

44. - E9B03

In the antenna radiation pattern shown in Figure E9-1, what is the front-to-side ratio?

Select	Answer
A	12 dB
B	24 dB
C	18 dB
D	14 dB

45. - E9C04

What happens to the radiation pattern of an unterminated long wire antenna as the wire length is increased?

Select	Answer
A	The lobes align more in the direction of the wire
B	The vertical angle increases
C	The front-to-back ratio decreases
D	The lobes become more perpendicular to the wire

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

47. - E9E04

What is the purpose of the series capacitor in a gamma-type antenna matching network?

Select	Answer
A	To cancel the inductive reactance of the matching network
B	To transform the antenna impedance to a higher value
C	To provide a rejection notch that prevents the radiation of harmonics
D	To provide DC isolation between the feed line and the antenna

48. - E9F05

What is the approximate physical length of a solid polyethylene dielectric coaxial transmission line that is electrically 1/4 wavelength long at 14.1 MHz?

Select	Answer
A	10.6 meters
B	4.3 meters
C	5.3 meters
D	3.5 meters

49. - E9G08

What is the process of normalization with regard to a Smith chart?

Select	Answer
A	Reassigning reactance values with regard to the resistance axis
B	Reassigning resistance values with regard to the reactance axis
C	Reassigning prime center with regard to the reactance axis
D	Reassigning impedance values with regard to the prime center

50. - E9H10

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

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

Figure E5-1

Figure E6-2

Figure E9-1