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

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1. - E0A11

Which of the following injuries can result from using high-power UHF or microwave transmitters?

Select	Answer
A	Hearing loss caused by high voltage corona discharge
B	Localized heating of the body from RF exposure in excess of the MPE limits
C	Blood clotting from the intense magnetic field
D	Ingestion of ozone gas from the cooling system

2. - E1A05

What is the maximum power output permitted on the 60 meter band?

Select	Answer
A	50 watts PEP effective radiated power relative to a dipole
B	100 watts PEP effective radiated power relative to an isotropic radiator
C	100 watts PEP effective radiated power relative to the gain of a half-wave dipole
D	50 watts PEP effective radiated power relative to an isotropic radiator

3. - E1B08

What limitations may the FCC place on an amateur station if its signal causes interference to domestic broadcast reception, assuming that the receivers involved are of good engineering design?

Select	Answer
A	The amateur station must cease operation on all frequencies below 30 MHz
B	The amateur station must cease operation on all frequencies above 30 MHz
C	The amateur station must avoid transmitting during certain hours on frequencies that cause the interference
D	The amateur station must cease operation

4. - E1C08

What is the maximum permissible duration of a remotely controlled station's transmissions if its control link malfunctions?

Select	Answer
A	30 seconds
B	3 minutes
C	10 minutes
D	5 minutes

5. - E1D04

Which of the following is required in the identification transmissions from a balloon-borne telemetry station?

Select	Answer
A	Call sign
B	The output power of the balloon transmitter
C	The station's six-character Maidenhead grid locator
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 send the documents to the FCC according to instructions
B	They must submit the application document to the coordinating VEC according to the coordinating VEC instructions
C	They must collect and submit the documents to the coordinating VEC for grading
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 temporary operation while awaiting normal licensing
B	To provide additional spectrum for personal use
C	To allow regular operation on Land Mobile channels
D	To provide for experimental amateur communications

8. - E2A06

What are Keplerian elements?

Select	Answer
A	High-emission heater filaments used in magnetron tubes
B	Phase reversing elements in a Yagi antenna
C	Encrypting codes used for spread spectrum modulation
D	Parameters that define the orbit of a satellite

9. - E2B05

Which of the following describes the use of vestigial sideband in analog fast-scan TV transmissions?

Select	Answer
A	Vestigial sideband provides high frequency emphasis to sharpen the picture
B	The vestigial sideband contains chroma information
C	Vestigial sideband reduces bandwidth while allowing for simple video detector circuitry
D	The vestigial sideband carries the audio information

10. - E2C08

Which of the following contacts may be confirmed through the U.S. QSL bureau system?

Select	Answer
A	Special event contacts between stations in the U.S.
B	Contacts using tactical call signs
C	Repeater contacts between U.S. club members
D	Contacts between a U.S. station and a non-U.S. station

11. - E2D06

Which of the following describes a method of establishing EME contacts?

Select	Answer
A	Time synchronous transmissions alternately from each station
B	High-speed CW identification to avoid fading
C	Judging optimum transmission times by monitoring beacons reflected from the moon
D	Storing and forwarding digital messages

12. - E2E06

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

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

13. - E3A09

Which of the following frequency ranges is most suited for meteor scatter communications?

Select	Answer
A	10 MHz - 14 MHz
B	1.8 MHz - 1.9 MHz
C	220 MHz - 450 MHz
D	28 MHz - 148 MHz

14. - E3B07

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

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

15. - E3C11

What does VOACAP software model?

Select	Answer
A	AC voltage and impedance
B	AC current and impedance
C	HF propagation
D	VHF radio propagation

16. - E4A01

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

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

17. - E4B07

What do the subscripts of S parameters represent?

Select	Answer
A	The port or ports at which measurements are made
B	Frequency order of the measurements
C	Relative quality of the data
D	The relative time between measurements

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

19. - E4D09

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

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

20. - E4E10

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

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

21. - E5A02

What is resonance in an LC or RLC circuit?

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

22. - E5B06

What is susceptance?

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

23. - E5C07

Where is the impedance of a pure resistance plotted on rectangular coordinates?

Select	Answer
A	On a line through the origin, slanted at 45 degrees
B	On the vertical axis
C	On the horizontal axis
D	On a horizontal line, offset vertically above the horizontal axis

24. - E5D08

How many watts are consumed in a circuit having a power factor of 0.6 if the input is 200VAC at 5 amperes?

Select	Answer
A	200 watts
B	1600 watts
C	1000 watts
D	600 watts

25. - E6A03

Why does a PN-junction diode not conduct current when reverse biased?

Select	Answer
A	Only N-type semiconductor material can conduct current
B	Only P-type semiconductor material can conduct current
C	Excess holes in P-type material combine with the electrons in N-type material, converting the entire diode into an insulator
D	Holes in P-type material and electrons in the N-type material are separated by the applied voltage, widening the depletion region

26. - E6B08

Which of the following is a Schottky barrier diode?

Select	Answer
A	Electrolytic rectifier
B	Metal-semiconductor junction
C	PIN junction
D	Thermionic emission diode

27. - E6C01

What is the function of hysteresis in a comparator?

Select	Answer
A	To increase the sensitivity
B	To cause the output to change states continually
C	To prevent input noise from causing unstable output signals
D	To allow the comparator to be used with AC input signals

28. - E6D03

Which of the following is an aspect of the piezoelectric effect?

Select	Answer
A	Generation of electrical energy in the presence of light
B	Mechanical deformation of material by the application of a magnetic field
C	Mechanical deformation of material by the application of a voltage
D	Increased conductivity in the presence of light

29. - E6E10

What advantage does surface-mount technology offer at RF compared to using through-hole components?

Select	Answer
A	Components have less parasitic inductance and capacitance
B	Shorter circuit-board traces
C	All these choices are correct
D	Smaller circuit area

30. - E6F06

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

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

31. - E7A08

What logical operation does an OR gate perform?

Select	Answer
A	It produces logic 1 at its output if any or all inputs are logic 1
B	It produces logic 1 at its output if all inputs are logic 0
C	It produces logic 0 at its output if all inputs are logic 1
D	It only produces logic 0 at its output when all inputs are 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 invert the sidebands causing distortion
B	Because they are relatively far in frequency from the desired signal
C	Because they are relatively close in frequency to the desired signal
D	Because they maintain the sidebands, thus causing multiple duplicate signals

33. - E7C11

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

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

34. - E7D01

How does a linear electronic voltage regulator work?

Select	Answer
A	The conduction of a control element is varied to maintain a constant output voltage
B	It has a ramp voltage as its output
C	It eliminates the need for a pass transistor
D	The control element duty cycle is proportional to the line or load conditions

35. - 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 driving a product detector with a DSB signal
C	By using a loop modulator followed by a mixer
D	By using a balanced modulator followed by a filter

36. - E7F01

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

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

37. - E7G02

What is ringing in a filter?

Select	Answer
A	Undesired oscillations added to the desired signal
B	A reduction in high frequency response
C	An echo caused by a long time delay
D	Partial cancellation of the signal over a range of frequencies

38. - E7H08

Which of the following components can be used to reduce thermal drift in crystal oscillators?

Select	Answer
A	Toroidal inductors
B	Wirewound resistors
C	NP0 capacitors
D	Non-inductive resistors

39. - E8A06

What is the approximate ratio of PEP-to-average power in a typical single-sideband phone signal?

Select	Answer
A	100 to 1
B	25 to 1
C	1 to 1
D	2.5 to 1

40. - E8B09

What is deviation ratio?

Select	Answer
A	The ratio of the maximum carrier frequency deviation to the highest audio modulating frequency
B	The ratio of the audio modulating frequency to the center carrier frequency
C	The ratio of the carrier center frequency to the audio modulating frequency
D	The ratio of the highest audio modulating frequency to the average audio modulating frequency

41. - E8C08

How does ARQ accomplish error correction?

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

42. - E8D04

What is the primary effect of extremely short rise or fall time on a CW signal?

Select	Answer
A	More difficult to copy
B	The generation of key clicks
C	The generation of RF harmonics
D	Limits data speed

43. - E9A07

What is the effective isotropic radiated power of a repeater station with 200 watts transmitter power output, 2 dB feed line loss, 2.8 dB duplexer loss, 1.2 dB circulator loss, and 7 dBi antenna gain?

Select	Answer
A	63.2 watts
B	632 watts
C	159 watts
D	252 watts

44. - E9B01

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

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

45. - E9C13

How does the radiation pattern of a horizontally polarized 3-element beam antenna vary with increasing height above ground?

Select	Answer
A	The horizontal beamwidth decreases
B	The takeoff angle of the lowest elevation lobe decreases
C	The horizontal beamwidth increases
D	The takeoff angle of the lowest elevation lobe increases

46. - E9D08

What happens as the Q of an antenna increases?

Select	Answer
A	SWR bandwidth decreases
B	More common-mode current is present on the feed line
C	Gain is reduced
D	SWR bandwidth increases

47. - E9E09

Which of the following is used to shunt-feed a grounded tower at its base?

Select	Answer
A	Hairpin match
B	Double-bazooka match
C	Gamma match
D	All these choices are correct

48. - E9F08

Which of the following is a significant difference between foam dielectric coaxial cable and solid dielectric cable, assuming all other parameters are the same?

Select	Answer
A	Foam dielectric has lower safe operating voltage limits
B	Foam dielectric has lower loss per unit of length
C	Foam dielectric has higher velocity factor
D	All these choices are correct

49. - E9G10

What do the arcs on a Smith chart represent?

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

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 increases signal strength by providing a better match to the feed line
D	It adds capacitive loading, increasing the bandwidth of the antenna

Figure E9-1