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

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1. - E0A02

When evaluating RF exposure levels from your station at a neighbor's home, what must you do?

Select	Answer
A	Ensure signals from your station are less than the uncontrolled Maximum Permitted Exposure (MPE) limits
B	Ensure signals from your station are less than the uncontrolled Maximum Permitted Emission (MPE) limits
C	Ensure signals from your station are less than the controlled Maximum Permitted Exposure (MPE) limits
D	Ensure signals from your station are less than the controlled Maximum Permitted Emission (MPE) limits

2. - E1A02

When using a transceiver that displays the carrier frequency of phone signals, which of the following displayed frequencies represents the lowest frequency at which a properly adjusted LSB emission will be totally within the band?

Select	Answer
A	300 Hz above the lower band edge
B	3 kHz above the lower band edge
C	1 kHz above the lower band edge
D	The exact lower band edge

3. - E1B01

Which of the following constitutes a spurious emission?

Select	Answer
A	An amateur station transmission made without the proper call sign identification
B	Any transmitted signal that unintentionally interferes with another licensed radio station
C	A signal transmitted to prevent its detection by any station other than the intended recipient
D	An emission outside the signal's necessary bandwidth that can be reduced or eliminated without affecting the information transmitted

4. - E1C14

How long must an operator wait after filing a notification with the Utilities Technology Council (UTC) before operating on the 2200 meter or 630 meter band?

Select	Answer
A	Operators may operate after 30 days, providing they have not been told that their station is within 1 km of PLC systems using those frequencies
B	Operations may commence immediately, and may continue unless interference is reported by the UTC
C	Operators may not operate until a test signal has been transmitted in coordination with the local power company
D	Operators must not operate until approval is received

5. - E1D01

What is the definition of telemetry?

Select	Answer
A	Two-way transmissions of data
B	One-way transmission of measurements at a distance from the measuring instrument
C	One-way transmission that initiates, modifies, or terminates the functions of a device at a distance
D	Two-way transmissions in excess of 1000 feet

6. - E1E02

Who does Part 97 task with maintaining the pools of questions for all U.S. amateur license examinations?

Select	Answer
A	The FCC
B	The VEs
C	The VECs
D	The ARRL

7. - E1F09

Which of the following conditions apply when transmitting spread spectrum emissions?

Select	Answer
A	The transmission must not be used to obscure the meaning of any communication
B	A station transmitting SS emission must not cause harmful interference to other stations employing other authorized emissions
C	All these choices are correct
D	The transmitting station must be in an area regulated by the FCC or in a country that permits SS emissions

8. - E2A08

Why should effective radiated power to a satellite that uses a linear transponder be limited?

Select	Answer
A	To avoid reducing the downlink power to all other users
B	To avoid interfering with terrestrial QSOs
C	To prevent the satellite from emitting out-of-band signals
D	To prevent creating errors in the satellite telemetry

9. - E2B09

What hardware, other than a receiver with SSB capability and a suitable computer, is needed to decode SSTV using Digital Radio Mondiale (DRM)?

Select	Answer
A	A special notch filter to remove synchronization pulses
B	No other hardware is needed
C	A special front end limiter
D	A special IF converter

10. - E2C05

What is the function of a DX QSL Manager?

Select	Answer
A	To relay calls to and from a DX station
B	To handle the receiving and sending of confirmation cards for a DX station
C	To allocate frequencies for DXpeditions
D	To run a net to allow many stations to contact a rare DX station

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. - E2E08

Which of the following HF digital modes can be used to transfer binary files?

Select	Answer
A	AMTOR
B	Hellschreiber
C	RTTY
D	PACTOR

13. - E3A01

What is the approximate maximum separation measured along the surface of the Earth between two stations communicating by EME?

Select	Answer
A	2000 miles, if the moon is at apogee
B	5000 miles, if the moon is at perigee
C	12,000 miles, if the moon is visible by both stations
D	500 miles, if the moon is at perigee

14. - E3B02

What is the approximate maximum range for signals using transequatorial propagation?

Select	Answer
A	5000 miles
B	2500 miles
C	1000 miles
D	7500 miles

15. - E3C09

How does the intensity of an X3 flare compare to that of an X2 flare?

Select	Answer
A	Twice as great
B	10 percent greater
C	Four times as great
D	50 percent greater

16. - E4A06

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

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

17. - E4B11

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

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

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

19. - E4D10

What does a third-order intercept level of 40 dBm mean with respect to receiver performance?

Select	Answer
A	Signals less than 40 dBm will not generate audible third-order intermodulation products
B	The receiver can tolerate signals up to 40 dB above the noise floor without producing third-order intermodulation products
C	A pair of 1 mW input signals will produce a third-order intermodulation product that is 40 dB stronger than the input signal
D	A pair of 40 dBm input signals will theoretically generate a third-order intermodulation product that has the same output amplitude as either of the input signals

20. - E4E09

What undesirable effect can occur when using an IF noise blanker?

Select	Answer
A	Received audio in the speech range might have an echo effect
B	Nearby signals may appear to be excessively wide even if they meet emission standards
C	FM signals can no longer be demodulated
D	The audio frequency bandwidth of the received signal might be compressed

21. - E5A01

What can cause the voltage across reactances in a series RLC circuit to be higher than the voltage applied to the entire circuit?

Select	Answer
A	Resonance
B	Resistance
C	Capacitance
D	Conductance

22. - E5B05

What happens to the magnitude of a pure reactance when it is converted to a susceptance?

Select	Answer
A	The sign is reversed
B	It is unchanged
C	It is shifted by 90 degrees
D	It becomes the reciprocal

23. - E5C03

Which of the following represents an inductive reactance in polar coordinates?

Select	Answer
A	A positive phase angle
B	A negative magnitude
C	A negative phase angle
D	A positive magnitude

24. - E5D02

Why is it important to keep lead lengths short for components used in circuits for VHF and above?

Select	Answer
A	To increase the thermal time constant
B	To avoid unwanted inductive reactance
C	To maintain component lifetime
D	All these choices are correct

25. - E6A11

In Figure E6-1, what is the schematic symbol for a P-channel junction FET?

Select	Answer
A	1
B	2
C	6
D	3

26. - E6B10

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

Select	Answer
A	1
B	5
C	7
D	6

27. - E6C02

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

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

28. - E6D13

What is the primary cause of inductor self-resonance?

Select	Answer
A	Inter-turn capacitance
B	Inductive kickback
C	The skin effect
D	Non-linear core hysteresis

29. - E6E09

Which of the following component package types would be most suitable for use at frequencies above the HF range?

Select	Answer
A	Radial lead
B	TO-220
C	Surface mount
D	Axial lead

30. - E6F04

What is the photovoltaic effect?

Select	Answer
A	The conversion of electrical energy to mechanical energy
B	The conversion of voltage to current when exposed to light
C	The tendency of a battery to discharge when exposed to light
D	The conversion of light to electrical energy

31. - E7A02

What is the function of a decade counter?

Select	Answer
A	It decodes a binary number for display on a seven-segment LED display
B	It produces one output pulse for every 10 input pulses
C	It produces 10 output pulses for every input pulse
D	It decodes a decimal number for display on a seven-segment LED display

32. - E7B17

Why are odd-order rather than even-order intermodulation distortion products of concern in linear power amplifiers?

Select	Answer
A	Because they are relatively close in frequency to the desired signal
B	Because they invert the sidebands causing distortion
C	Because they maintain the sidebands, thus causing multiple duplicate signals
D	Because they are relatively far in frequency from the desired signal

33. - E7C03

What advantage does a series-L Pi-L-network have over a series-L Pi-network for impedance matching between the final amplifier of a vacuum-tube transmitter and an antenna?

Select	Answer
A	Higher efficiency
B	Does not require a capacitor
C	Greater harmonic suppression
D	Greater transformation range

34. - E7D13

What is the equation for calculating power dissipated by a series linear voltage regulator?

Select	Answer
A	Input voltage divided by output current
B	Voltage difference from input to output multiplied by output current
C	Input voltage multiplied by input current
D	Output voltage multiplied by output current

35. - E7E11

Which type of detector circuit is used for demodulating SSB signals?

Select	Answer
A	Discriminator
B	Phase comparator
C	Phase detector
D	Product detector

36. - E7F05

How frequently must an analog signal be sampled by an analog-to-digital converter so that the signal can be accurately reproduced?

Select	Answer
A	At least twice the rate of the highest frequency component of the signal
B	At least half the rate of the highest frequency component of the signal
C	At the same rate as the highest frequency component of the signal
D	At four times the rate of the highest frequency component of the signal

37. - E7G04

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

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

38. - E7H12

Which of the following must be done to ensure that a crystal oscillator provides the frequency specified by the crystal manufacturer?

Select	Answer
A	Bias the crystal at a specified current
B	Provide the crystal with a specified parallel capacitance
C	Provide the crystal with a specified parallel inductance
D	Bias the crystal at a specified voltage

39. - E8A02

Which of the following is a type of analog-to-digital conversion?

Select	Answer
A	Phase reversal
B	Level shifting
C	Harmonic regeneration
D	Successive approximation

40. - E8B11

What is digital time division multiplexing?

Select	Answer
A	Two or more data streams share the same channel by transmitting time of transmission as the sub-carrier
B	Two or more signals are arranged to share discrete time slots of a data transmission
C	Two or more data streams are assigned to discrete sub-carriers on an FM transmitter
D	Two or more signals are quadrature modulated to increase bandwidth efficiency

41. - E8C03

Why should phase-shifting of a PSK signal be done at the zero crossing of the RF signal?

Select	Answer
A	To improve carrier suppression
B	All these choices are correct
C	To simplify modulation
D	To minimize bandwidth

42. - E8D01

Why are received spread spectrum signals resistant to interference?

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

43. - E9A12

How much gain does an antenna have compared to a 1/2-wavelength dipole when it has 6 dB gain over an isotropic antenna?

Select	Answer
A	6.0 dB
B	2.79 dB
C	8.15 dB
D	3.85 dB

44. - E9B10

What is the principle of a Method of Moments analysis?

Select	Answer
A	A wire is modeled as a series of segments, each having a distinct value of voltage across it
B	A wire is modeled as a single sine-wave current generator
C	A wire is modeled as a single sine-wave voltage source
D	A wire is modeled as a series of segments, each having a uniform value of current

45. - E9C09

Which of the following describes a G5RV antenna?

Select	Answer
A	A wide band dipole using shorted coaxial cable for the radiating elements and fed with a�4:1 balun
B	A multi-band dipole antenna fed with coax and a balun through a selected length of open wire transmission line
C	A phased array antenna consisting of multiple loops
D	A multi-band trap antenna

46. - E9D01

How much does the gain of an ideal parabolic dish antenna change when the operating frequency is doubled?

Select	Answer
A	6 dB
B	2 dB
C	4 dB
D	3 dB

47. - E9E06

Which of these feed line impedances would be suitable for constructing a quarter-wave Q-section for matching a 100-ohm loop to 50-ohm feed line?

Select	Answer
A	450 ohms
B	50 ohms
C	75 ohms
D	62 ohms

48. - E9F04

What impedance does a 1/2-wavelength transmission line present to a generator when the line is shorted at the far end?

Select	Answer
A	Very low impedance
B	Very high impedance
C	The same as the characteristic impedance of the line
D	The same as the output impedance of the generator

49. - E9G05

Which of the following is a common use for a Smith chart?

Select	Answer
A	Determine the impedance of a transmission line, given the physical dimensions
B	Determine the gain of an antenna given the physical and electrical parameters
C	Determine the loss/100 feet of a transmission line, given the velocity factor and conductor materials
D	Determine the length and position of an impedance matching stub

50. - E9H04

What is an advantage of placing a grounded electrostatic shield around a small loop direction-finding antenna?

Select	Answer
A	It eliminates tracking errors caused by strong out-of-band signals
B	It increases signal strength by providing a better match to the feed line
C	It adds capacitive loading, increasing the bandwidth of the antenna
D	It eliminates unbalanced capacitive coupling to the surroundings, improving the nulls

Figure E6-1

Figure E6-2