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. - E1A14

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

Select	Answer
A	1 watt EIRP
B	100 watts PEP
C	50 watts PEP
D	5 watts 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 letter of intent must be filed with the Environmental Protection Agency
C	A form FSD-15 must be submitted to the Department of the Interior
D	A proposal must be submitted to the National Park Service

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

5. - E1D10

Which amateur stations are eligible to be telecommand stations of space stations (subject to the privileges of the class of operator license held by the control operator of the station)?

Select	Answer
A	Any amateur station so designated by the ITU
B	Any amateur station so designated by the space station licensee
C	All these choices are correct
D	Any amateur station designated by NASA

6. - E1E01

For which types of out-of-pocket expenses do the Part 97 rules state that VEs and VECs may be reimbursed?

Select	Answer
A	Providing amateur operator license examination preparation training materials
B	Teaching an amateur operator license examination preparation course
C	Preparing, processing, administering, and coordinating an examination for an amateur radio operator license
D	No expenses are authorized for reimbursement

7. - E1F01

On what frequencies are spread spectrum transmissions permitted?

Select	Answer
A	Only on amateur frequencies above 144 MHz
B	Only on amateur frequencies above 222 MHz
C	Only on amateur frequencies above 420 MHz
D	Only on amateur frequencies above 50 MHz

8. - E2A07

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

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

9. - E2B11

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

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

10. - E2C10

Why might a DX station state that they are listening on another frequency?

Select	Answer
A	To improve operating efficiency by reducing interference
B	Because the DX station may be transmitting on a frequency that is prohibited to some responding stations
C	To separate the calling stations from the DX station
D	All these choices are correct

11. - E2D01

Which of the following digital modes is designed for meteor scatter communications?

Select	Answer
A	WSPR
B	APRS
C	MSK144
D	Hellschreiber

12. - E2E04

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

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

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

14. - E3B12

What is the primary characteristic of chordal hop propagation?

Select	Answer
A	Signals reflected back toward the transmitting station
B	Propagation across the geomagnetic equator
C	Successive ionospheric refractions without an intermediate reflection from the ground
D	Propagation away from the great circle bearing between stations

15. - E3C11

What does VOACAP software model?

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

16. - E4A09

Which of the following is good practice when using an oscilloscope probe?

Select	Answer
A	Keep the signal ground connection of the probe as short as possible
B	Never use a high-impedance probe to measure a low-impedance circuit
C	Never use a DC-coupled probe to measure an AC circuit
D	All these choices are correct

17. - E4B09

What is indicated if the current reading on an RF ammeter placed in series with the antenna feed line of a transmitter increases as the transmitter is tuned to resonance?

Select	Answer
A	There is more power going into the antenna
B	There is possibly a short to ground in the feed line
C	There is an impedance mismatch between the antenna and feed line
D	The transmitter is not properly neutralized

18. - E4C01

What is an effect of excessive phase noise in a receiver's local oscillator?

Select	Answer
A	It decreases receiver third-order intercept point
B	It can affect the receiver's frequency calibration
C	It limits the receiver's ability to receive strong signals
D	It can combine with strong signals on nearby frequencies to generate interference

19. - E4D08

What causes intermodulation in an electronic circuit?

Select	Answer
A	Positive feedback
B	Nonlinear circuits or devices
C	Too little gain
D	Lack of neutralization

20. - E4E01

What problem can occur when using an automatic notch filter (ANF) to remove interfering carriers while receiving CW signals?

Select	Answer
A	Received CW signals will appear to be modulated at the DSP clock frequency
B	Removal of the CW signal as well as the interfering carrier
C	Any nearby signal passing through the DSP system will overwhelm the desired signal
D	Ringing in the DSP filter will completely remove the spaces between the CW characters

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 highest frequency that will pass current
D	The frequency at which the reactive impedance equals the resistive impedance

22. - E5B04

What is the time constant of a circuit having two 220-microfarad capacitors and two 1-megohm resistors, all in parallel?

Select	Answer
A	220 seconds
B	55 seconds
C	440 seconds
D	110 seconds

23. - E5C11

Which point in Figure E5-1 best represents the impedance of a series circuit consisting of a 300-ohm resistor and an 18-microhenry inductor at 3.505 MHz?

Select	Answer
A	Point 8
B	Point 1
C	Point 7
D	Point 3

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	600 watts
B	200 watts
C	1600 watts
D	1000 watts

25. - E6A04

What is the name given to an impurity atom that adds holes to a semiconductor crystal structure?

Select	Answer
A	Acceptor impurity
B	N-type impurity
C	Donor impurity
D	Insulator impurity

26. - E6B10

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

Select	Answer
A	7
B	5
C	1
D	6

27. - E6C02

What happens when the level of a comparator's input signal crosses the threshold?

Select	Answer
A	The IC input can be damaged
B	The comparator changes its output state
C	The comparator enters latch-up
D	The feedback loop becomes unstable

28. - E6D12

What is inductor saturation?

Select	Answer
A	The ability of the inductor's core to store magnetic energy has been exceeded
B	The inductor windings are over-coupled
C	The inductor's voltage rating is exceeded causing a flashover
D	Adjacent inductors become over-coupled

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 nitride
C	Silicon dioxide
D	Silicon

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. - E7A07

What logical operation does a NAND gate perform?

Select	Answer
A	It produces logic 0 at its output only when all inputs are logic 1
B	It produces logic 1 at its output only when all inputs are logic 1
C	It produces logic 0 at its output if some but not all inputs are logic 1
D	It produces logic 0 at its output only when all inputs are logic 0

32. - E7B08

How can an RF power amplifier be neutralized?

Select	Answer
A	By increasing the driving power
B	By feeding a 180-degree out-of-phase portion of the output back to the input
C	By reducing the driving power
D	By feeding an in-phase component of the output back to the input

33. - E7C04

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

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

34. - E7D12

What is the dropout voltage of an analog voltage regulator?

Select	Answer
A	Maximum that the output voltage may decrease at rated load
B	Minimum input voltage for rated power dissipation
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. - E7E10

How does a diode envelope detector function?

Select	Answer
A	By breakdown of the Zener voltage
B	By rectification and filtering of RF signals
C	By mixing signals with noise in the transition region of the diode
D	By sensing the change of reactance in the diode with respect to frequency

36. - E7F06

What is the minimum number of bits required for an analog-to-digital converter to sample a signal with a range of 1 volt at a resolution of 1 millivolt?

Select	Answer
A	6 bits
B	8 bits
C	4 bits
D	10 bits

37. - E7G04

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

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

38. - E7H04

How is positive feedback supplied in a Colpitts oscillator?

Select	Answer
A	Through a capacitive divider
B	Through a neutralizing capacitor
C	Through link coupling
D	Through a tapped coil

39. - E8A06

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

Select	Answer
A	2.5 to 1
B	1 to 1
C	25 to 1
D	100 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 carrier center frequency to the audio modulating frequency
C	The ratio of the audio modulating frequency to the center carrier frequency
D	The ratio of the highest audio modulating frequency to the average audio modulating frequency

41. - E8C07

What is the bandwidth of a 4800-Hz frequency shift, 9600-baud ASCII FM transmission?

Select	Answer
A	9.6 kHz
B	15.36 kHz
C	5.76 kHz
D	4.8 kHz

42. - E8D06

What is the advantage of including parity bits in ASCII characters?

Select	Answer
A	The signal can overpower interfering signals
B	Foreign language characters can be sent
C	Faster transmission rate
D	Some types of errors can be detected

43. - E9A13

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

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

44. - E9B08

What is the far field of an antenna?

Select	Answer
A	The region where radiated power dissipates over a specified time period
B	The region where the shape of the antenna pattern is independent of distance
C	The region where radiated field strengths are constant
D	The region of the ionosphere where radiated power is not refracted

45. - E9C11

How is the far-field elevation pattern of a vertically polarized antenna affected by being mounted over seawater versus soil?

Select	Answer
A	Fewer vertical angle lobes will be present
B	The low-angle radiation decreases
C	Additional higher vertical angle lobes will appear
D	The low-angle radiation increases

46. - E9D08

What happens as the Q of an antenna increases?

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

47. - E9E05

How must an antenna's driven element be tuned to use a hairpin matching system?

Select	Answer
A	The driven element radiation resistance must be higher than the characteristic impedance of the transmission line
B	The driven element reactance must be capacitive
C	The driven element reactance must be inductive
D	The driven element resonance must be lower than the operating frequency

48. - E9F03

Why is the physical length of a coaxial cable transmission line shorter than its electrical length?

Select	Answer
A	Skin effect is less pronounced in the coaxial cable
B	The surge impedance is higher in a parallel feed line
C	Electrical signals move more slowly in a coaxial cable than in air
D	The characteristic impedance is higher in a parallel feed line

49. - E9G04

What are the two families of circles and arcs that make up a Smith chart?

Select	Answer
A	Reactance and voltage
B	Resistance and voltage
C	Voltage and impedance
D	Resistance and reactance

50. - E9H10

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

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

Figure E5-1

Figure E6-2