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

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1. - E0A04

When evaluating a site with multiple transmitters operating at the same time, the operators and licensees of which transmitters are responsible for mitigating over-exposure situations?

Select	Answer
A	Each transmitter operating with a duty cycle greater than 50 percent
B	Only commercial transmitters
C	Only the most powerful transmitter
D	Each transmitter that produces 5 percent or more of its MPE limit in areas where the total MPE limit is exceeded.

2. - E1A03

What is the maximum legal carrier frequency on the 20 meter band for transmitting USB AFSK digital signals having a 1 kHz bandwidth?

Select	Answer
A	14.149 MHz
B	14.100 MHz
C	14.349 MHz
D	14.070 MHz

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

4. - E1C12

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

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

5. - E1D06

What is the maximum permitted transmitter output power when operating a model craft by telecommand?

Select	Answer
A	100 watts
B	1 watt
C	2 watts
D	5 watts

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 collect and send the documents to the NCVEC for grading
C	They must collect and submit the documents to the coordinating VEC for grading
D	They must submit the application document to the coordinating VEC according to the coordinating VEC instructions

7. - E1F08

Which of the following types of amateur station communications are prohibited?

Select	Answer
A	Communications transmitted for hire or material compensation, except as otherwise provided in the rules
B	Communications in a language other than English
C	Communications that have religious content
D	Communications that have political content, except as allowed by the Fairness Doctrine

8. - E2A01

What is the direction of an ascending pass for an amateur satellite?

Select	Answer
A	From north to south
B	From west to east
C	From east to west
D	From south to north

9. - E2B10

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

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

10. - E2C06

During a VHF/UHF contest, in which band segment would you expect to find the highest level of SSB or CW activity?

Select	Answer
A	In the middle of the band, usually 25 kHz above the national calling frequency
B	In the weak signal segment of the band, with most of the activity near the calling frequency
C	At the top of each band, usually in a segment reserved for contests
D	In the middle of each band, usually on the national calling frequency

11. - E2D03

Which of the following digital modes is especially useful for EME communications?

Select	Answer
A	JT65
B	MSK144
C	PACTOR III
D	Olivia

12. - E2E09

Which of the following HF digital modes uses variable-length coding for bandwidth efficiency?

Select	Answer
A	RTTY
B	MT63
C	PACTOR
D	PSK31

13. - E3A09

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

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

14. - E3B09

At what time of year is sporadic E propagation most likely to occur?

Select	Answer
A	Around the equinoxes, especially the spring equinox
B	Around the solstices, especially the summer solstice
C	Around the equinoxes, especially the fall equinox
D	Around the solstices, especially the winter solstice

15. - E3C04

What does the value of Bz (B sub Z) represent?

Select	Answer
A	Critical frequency for vertical transmissions
B	Duration of long-delayed echoes
C	Direction and strength of the interplanetary magnetic field
D	Geomagnetic field stability

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

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

18. - E4C12

Which of the following has the largest effect on an SDR receiver's dynamic range?

Select	Answer
A	CPU register width in bits
B	Anti-aliasing input filter bandwidth
C	RAM speed used for data storage
D	Analog-to-digital converter sample width in bits

19. - E4D01

What is meant by the blocking dynamic range of a receiver?

Select	Answer
A	The minimum difference in dB between two signals which produce third-order intermodulation products greater than the noise floor
B	The difference in dB between the noise floor and the third-order intercept point
C	The difference in dB between the noise floor and the level of an incoming signal that will cause 1 dB of gain compression
D	The minimum difference in dB between the levels of two FM signals that will cause one signal to block the other

20. - E4E02

Which of the following types of noise can often be reduced with a digital signal processing noise filter?

Select	Answer
A	All these choices are correct
B	Ignition noise
C	Broadband white noise
D	Power line noise

21. - E5A09

How is the Q of an RLC parallel resonant circuit calculated?

Select	Answer
A	Reactance of the inductance multiplied by the reactance of the capacitance
B	Reactance of either the inductance or capacitance divided by the resistance
C	Reactance of either the inductance or capacitance multiplied by the resistance
D	Resistance divided by the reactance of either the inductance or capacitance

22. - E5B12

What is admittance?

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

23. - E5C01

Which of the following represents capacitive reactance in rectangular notation?

Select	Answer
A	Omega
B	-jX
C	Delta
D	+jX

24. - E5D06

In what direction is the magnetic field oriented about a conductor in relation to the direction of electron flow?

Select	Answer
A	In the same direction as the current
B	In a circle around the conductor
C	In a direction opposite to the current
D	In all directions; omni-directional

25. - E6A04

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

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

26. - E6B10

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

Select	Answer
A	6
B	5
C	7
D	1

27. - E6C10

In Figure E6-3, what is the schematic symbol for a NOR gate?

Select	Answer
A	4
B	3
C	2
D	1

28. - E6D04

Which materials are commonly used as a core in an inductor?

Select	Answer
A	Teflon and Delrin
B	Cobalt and aluminum
C	Polystyrene and polyethylene
D	Ferrite and brass

29. - E6E02

Which of the following device packages is a through-hole type?

Select	Answer
A	PLCC
B	Ball grid array
C	SOT
D	DIP

30. - E6F02

What happens to the conductivity of a photoconductive material when light shines on it?

Select	Answer
A	It decreases
B	It increases
C	It becomes unstable
D	It stays the same

31. - E7A05

Which of the following is a circuit that continuously alternates between two states without an external clock?

Select	Answer
A	J-K flip-flop
B	Astable multivibrator
C	Monostable multivibrator
D	T flip-flop

32. - E7B15

What is one way to prevent thermal runaway in a bipolar transistor amplifier?

Select	Answer
A	Neutralization
B	Select transistors with high beta
C	All these choices are correct
D	Use a resistor in series with the emitter

33. - E7C02

Which of the following is a property of a T-network with series capacitors and a parallel shunt inductor?

Select	Answer
A	It is a band-pass filter
B	It is a high-pass filter
C	It is a low-pass filter
D	It is a notch filter

34. - E7D09

What is the main reason to use a charge controller with a solar power system?

Select	Answer
A	Prevention of battery damage due to overcharge
B	Matching of day and night charge rates
C	Prevention of battery undercharge
D	Control of electrolyte levels during battery discharge

35. - E7E10

How does a diode envelope detector function?

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

36. - E7F08

What is the function of decimation?

Select	Answer
A	Attenuating the signal
B	Removing unnecessary significant digits
C	Converting data to binary code decimal form
D	Reducing the effective sample rate by removing samples

37. - E7G07

What magnitude of voltage gain can be expected from the circuit in Figure E73 when R1 is 10 ohms and RF is 470 ohms?

Select	Answer
A	0.21
B	24
C	47
D	94

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

39. - E8A05

What of the following instruments would be the most accurate for measuring the RMS voltage of a complex waveform?

Select	Answer
A	A true-RMS calculating meter
B	A D'Arsonval meter
C	An absorption wave meter
D	A grid dip meter

40. - E8B02

How does the modulation index of a phase-modulated emission vary with RF carrier frequency?

Select	Answer
A	It varies with the square root of the RF carrier frequency
B	It does not depend on the RF carrier frequency
C	It decreases as the RF carrier frequency increases
D	It increases as the RF carrier frequency increases

41. - E8C12

What factors affect the bandwidth of a transmitted CW signal?

Select	Answer
A	Keying speed and shape factor (rise and fall time)
B	All these choices are correct
C	Modulation index and output power
D	IF bandwidth and Q

42. - E8D09

What is considered an acceptable maximum IMD level for an idling PSK signal?

Select	Answer
A	+10 dB
B	+15 dB
C	-20 dB
D	-30 dB

43. - E9A03

What is the radiation resistance of an antenna?

Select	Answer
A	The resistance in the atmosphere that an antenna must overcome to be able to radiate a signal
B	The specific impedance of the antenna
C	The value of a resistance that would dissipate the same amount of power as that radiated from an antenna
D	The combined losses of the antenna elements and feed line

44. - E9B07

How does the total amount of radiation emitted by a directional gain antenna compare with the total amount of radiation emitted from a theoretical isotropic antenna, assuming each is driven by the same amount of power?

Select	Answer
A	The radiation from the isotropic antenna is 2.15 dB stronger than that from the directional antenna
B	The total amount of radiation from the directional antenna is stronger by its front-to-back ratio
C	They are the same
D	The total amount of radiation from the directional antenna is increased by the gain of the antenna

45. - E9C07

What is the approximate feed point impedance at the center of a two-wire folded dipole antenna?

Select	Answer
A	50 ohms
B	300 ohms
C	72 ohms
D	450 ohms

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	SWR bandwidth increases
D	Gain is reduced

47. - E9E09

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

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

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

49. - E9G09

What third family of circles is often added to a Smith chart during the process of solving problems?

Select	Answer
A	Coaxial-length circles
B	Radiation-pattern circles
C	Antenna-length circles
D	Standing wave ratio circles

50. - E9H11

What feature of a cardioid pattern antenna makes it useful for direction finding?

Select	Answer
A	A very sharp peak
B	High radiation angle
C	Broadband response
D	A very sharp single null

Figure E6-2

Figure E6-3