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

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1. - E0A06

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

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

2. - E1A12

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

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

3. - E1B07

To what type of regulations does PRB-1 apply?

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

4. - E1C01

What is the maximum bandwidth for a data emission on 60 meters?

Select	Answer
A	170 Hz
B	60 Hz
C	2.8 kHz
D	1.5 kHz

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

7. - E1F07

When may an amateur station send a message to a business?

Select	Answer
A	When neither the amateur nor his or her employer has a pecuniary interest in the communications
B	When the control operator is employed by the FCC or another government agency
C	When transmitting international third-party communications
D	When the total money involved does not exceed $25

8. - E2A07

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

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

9. - E2B11

What is the function of the Vertical Interval Signaling (VIS) code sent as part of an SSTV transmission?

Select	Answer
A	To identify the call sign of the station transmitting
B	To lock the color burst oscillator in color SSTV images
C	To identify the SSTV mode being used
D	To provide vertical synchronization

10. - E2C07

What is the Cabrillo format?

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

11. - E2D09

What type of modulation is used for JT65 contacts?

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

12. - E2E12

How do ALE stations establish contact?

Select	Answer
A	ALE radios activate when they hear their signal echoed by back scatter
B	ALE constantly scans a list of frequencies, activating the radio when the designated call sign is received
C	ALE radios monitor an internet site for the frequency they are being paged on
D	ALE radios send a constant tone code to establish a frequency for future use

13. - E3A03

When scheduling EME contacts, which of these conditions will generally result in the least path loss?

Select	Answer
A	When the moon is full
B	When the moon is at perigee
C	When the MUF is above 30 MHz
D	When the moon is at apogee

14. - E3B06

Which of the following amateur bands most frequently provides long-path propagation?

Select	Answer
A	20 meters
B	80 meters
C	10 meters
D	6 meters

15. - E3C05

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

Select	Answer
A	Westward
B	Northward
C	Southward
D	Eastward

16. - E4A02

Which of the following parameters does a spectrum analyzer display on the vertical and horizontal axes?

Select	Answer
A	SWR and frequency
B	RF amplitude and frequency
C	RF amplitude and time
D	SWR and time

17. - E4B04

Which S parameter represents input port return loss or reflection coefficient (equivalent to VSWR)?

Select	Answer
A	S21
B	S11
C	S12
D	S22

18. - E4C15

What is reciprocal mixing?

Select	Answer
A	Local oscillator phase noise mixing with adjacent strong signals to create interference to desired signals
B	In-phase signals cancelling in a mixer resulting in loss of receiver sensitivity
C	Two out-of-band signals mixing to generate an in-band spurious signal
D	Two digital signals combining from alternate time slots

19. - E4D11

Why are odd-order intermodulation products, created within a receiver, of particular interest compared to other products?

Select	Answer
A	Odd-order products overload the IF filters
B	Odd-order products are an indication of poor image rejection
C	Odd-order intermodulation produces three products for every input signal within the band of interest
D	Odd-order products of two signals in the band of interest are also likely to be within the band

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

21. - E5A15

Which of the following increases Q for inductors and capacitors?

Select	Answer
A	Higher self-resonant frequency
B	Lower losses
C	Lower self-resonant frequency
D	Lower reactance

22. - E5B02

What letter is commonly used to represent susceptance?

Select	Answer
A	Y
B	G
C	B
D	X

23. - E5C06

What does the impedance 50-j25 represent?

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

24. - E5D13

How many watts are consumed in a circuit consisting of a 100-ohm resistor in series with a 100-ohm inductive reactance drawing 1 ampere?

Select	Answer
A	70.7 watts
B	100 watts
C	141.4 watts
D	200 watts

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 keep the gate voltage within specifications and prevent the device from overheating
C	To reduce the chance of static damage to the gate
D	To provide a voltage reference for the correct amount of reverse-bias gate voltage

26. - E6B09

What is a common use for point-contact diodes?

Select	Answer
A	As a constant current source
B	As an RF detector
C	As a high-voltage rectifier
D	As a constant voltage source

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	All these choices are correct
D	Its simplicity results in much less expensive devices than standard CMOS

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

29. - E6E03

Which of the following materials is likely to provide the highest frequency of operation when used in MMICs?

Select	Answer
A	Gallium nitride
B	Silicon dioxide
C	Silicon
D	Silicon nitride

30. - E6F01

What absorbs the energy from light falling on a photovoltaic cell?

Select	Answer
A	Holes
B	Electrons
C	Photons
D	Protons

31. - E7A08

What logical operation does an OR gate perform?

Select	Answer
A	It produces logic 1 at its output if all inputs are logic 0
B	It only produces logic 0 at its output when all inputs are logic 1
C	It produces logic 1 at its output if any or all inputs are logic 1
D	It produces logic 0 at its output if all inputs are logic 1

32. - E7B05

What can be done to prevent unwanted oscillations in an RF power amplifier?

Select	Answer
A	Tune both the input and output for maximum power
B	Install parasitic suppressors and/or neutralize the stage
C	Use a phase inverter in the output filter
D	Tune the stage for maximum SWR

33. - E7C01

How are the capacitors and inductors of a low-pass filter Pi-network arranged between the network's input and output?

Select	Answer
A	An inductor is connected between the input and ground, another inductor is connected between the output and ground, and a capacitor is connected between the input and output
B	Two inductors are in series between the input and output, and a capacitor is connected between the two inductors and ground
C	Two capacitors are in series between the input and output, and an inductor is connected between the two capacitors and ground
D	A capacitor is connected between the input and ground, another capacitor is connected between the output and ground, and an inductor is connected between input and output

34. - 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	The high frequency inverter design uses much smaller transformers and filter components for an equivalent power output
D	It uses a large power factor compensation capacitor to recover power from the unused portion of the AC cycle

35. - E7E08

What are the principal frequencies that appear at the output of a mixer circuit?

Select	Answer
A	The square root of the product of input frequencies
B	Two and four times the original frequency
C	1.414 and 0.707 times the input frequency
D	The two input frequencies along with their sum and difference frequencies

36. - E7F14

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

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

37. - E7G02

What is ringing in a filter?

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

38. - E7H08

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

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

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

40. - E8B07

Orthogonal Frequency Division Multiplexing is a technique used for which type of amateur communication?

Select	Answer
A	EME
B	High-speed digital modes
C	Extremely low-power contacts
D	OFDM signals are not allowed on amateur bands

41. - E8C04

What technique minimizes the bandwidth of a PSK31 signal?

Select	Answer
A	Use of sinusoidal data pulses
B	Use of trapezoidal data pulses
C	Zero-sum character encoding
D	Reed-Solomon character encoding

42. - E8D01

Why are received spread spectrum signals resistant to interference?

Select	Answer
A	The receiver is always equipped with a digital blanker
B	If interference is detected by the receiver it will signal the transmitter to change frequencies
C	The high power used by a spread spectrum transmitter keeps its signal from being easily overpowered
D	Signals not using the spread spectrum algorithm are suppressed in the receiver

43. - E9A13

What term describes station output, taking into account all gains and losses?

Select	Answer
A	Effective radiated power
B	Apparent power
C	Power factor
D	Half-power bandwidth

44. - E9B04

What is the front-to-back ratio of the radiation pattern shown in Figure E92?

Select	Answer
A	15 dB
B	3 dB
C	28 dB
D	38 dB

45. - E9C14

How does the performance of a horizontally polarized antenna mounted on the side of a hill compare with the same antenna mounted on flat ground?

Select	Answer
A	The horizontal beamwidth decreases in the downhill direction
B	The horizontal beamwidth increases in the uphill direction
C	The main lobe takeoff angle decreases in the downhill direction
D	The main lobe takeoff angle increases in the downhill direction

46. - E9D03

Where should a high Q loading coil be placed to minimize losses in a shortened vertical antenna?

Select	Answer
A	As low as possible on the vertical radiator
B	At a voltage node
C	Near the center of the vertical radiator
D	As close to the transmitter as possible

47. - 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 omega match
C	The gamma match
D	The stub match

48. - E9F06

What is the approximate physical length of an air-insulated, parallel conductor transmission line that is electrically 1/2 wavelength long at 14.10 MHz?

Select	Answer
A	8.5 meters
B	10.6 meters
C	7.0 meters
D	13.3 meters

49. - E9G02

What type of coordinate system is used in a Smith chart?

Select	Answer
A	Resistance lines and reactance chords
B	Voltage lines and current chords
C	Resistance circles and reactance arcs
D	Voltage circles and current arcs

50. - E9H10

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

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