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

2. - E1A07

What is the maximum power permitted on the 2200 meter band?

Select	Answer
A	1 watt EIRP (Equivalent isotropic radiated power)
B	5 watts EIRP (Equivalent isotropic radiated power)
C	100 watts PEP
D	50 watts PEP

3. - E1B11

What does PRB-1 require of regulations affecting amateur radio?

Select	Answer
A	Amateur radio operations must be permitted in any private residence
B	No limitations may be placed on antenna size or placement
C	Use of wireless devices in a vehicle is exempt from regulation
D	Reasonable accommodations of amateur radio must be made

4. - E1C01

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

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

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

6. - E1E05

What is the minimum passing score on all amateur operator license examinations?

Select	Answer
A	Minimum passing score of 70%
B	Minimum passing score of 80%
C	Minimum passing score of 74%
D	Minimum passing score of 77%

7. - E1F08

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

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

8. - E2A03

How is the signal inverted by an inverting linear transponder?

Select	Answer
A	The signal is reduced to I and Q components and the Q component is filtered out
B	The signal is passed through a non-linear filter
C	The signal is passed through a mixer and the difference rather than the sum is transmitted
D	The signal is detected and remodulated on the reverse sideband

9. - E2B03

How is an interlaced scanning pattern generated in a fast-scan (NTSC) television system?

Select	Answer
A	By scanning each field from bottom to top
B	By scanning lines from left to right in one field and right to left in the next
C	By scanning two fields simultaneously
D	By scanning odd numbered lines in one field and even numbered lines in the next

10. - E2C12

What technique do individual nodes use to form a mesh network?

Select	Answer
A	Custom code plugs for the local trunking systems
B	Discovery and link establishment protocols
C	Acting as store-and-forward digipeaters
D	Forward error correction and Viterbi codes

11. - E2D02

Which of the following is a good technique for making meteor scatter contacts?

Select	Answer
A	Use of special digital modes
B	Short transmissions with rapidly repeated call signs and signal reports
C	15-second timed transmission sequences with stations alternating based on location
D	All these choices are correct

12. - E2E09

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

Select	Answer
A	MT63
B	PACTOR
C	RTTY
D	PSK31

13. - E3A01

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

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

14. - E3B11

At what time of day can sporadic E propagation occur?

Select	Answer
A	Any time
B	Only around sunset and sunrise
C	Only in hours of darkness
D	Only around sunset

15. - E3C03

Which of the following signal paths is most likely to experience high levels of absorption when the A index or K index is elevated?

Select	Answer
A	Transequatorial
B	Polar
C	NVIS
D	Sporadic E

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. - E4B08

Which of the following can be used to measure the Q of a series-tuned circuit?

Select	Answer
A	The frequency shift
B	The resonant frequency of the circuit
C	The bandwidth of the circuit's frequency response
D	The inductance to capacitance ratio

18. - E4C02

Which of the following receiver circuits can be effective in eliminating interference from strong out-of-band signals?

Select	Answer
A	A notch filter
B	A narrow IF filter
C	A properly adjusted product detector
D	A front-end filter or pre-selector

19. - E4D07

Which of the following reduces the likelihood of receiver desensitization?

Select	Answer
A	Switch from fast AGC to slow AGC
B	Raise the receiver IF frequency
C	Decrease the RF bandwidth of the receiver
D	Increase the receiver front end gain

20. - E4E05

How can radio frequency interference from an AC motor be suppressed?

Select	Answer
A	By installing a high-pass filter in series with the motor's power leads
B	By installing a bypass capacitor in series with the motor leads
C	By using a ground-fault current interrupter in the circuit used to power the motor
D	By installing a brute-force AC-line filter in series with the motor leads

21. - E5A11

What is the half-power bandwidth of a resonant circuit that has a resonant frequency of 7.1 MHz and a Q of 150?

Select	Answer
A	157.8 Hz
B	47.3 kHz
C	315.6 Hz
D	23.67 kHz

22. - E5B07

What is the phase angle between the voltage across and the current through a series RLC circuit if XC is 500 ohms, R is 1 kilohm, and XL is 250 ohms?

Select	Answer
A	14.0 degrees with the voltage lagging the current
B	14.0 degrees with the voltage leading the current
C	68.2 degrees with the voltage lagging the current
D	68.2 degrees with the voltage leading the current

23. - E5C02

How are impedances described in polar coordinates?

Select	Answer
A	By phase angle and magnitude
B	By Y and G values
C	By X and R values
D	By real and imaginary parts

24. - E5D04

Why are short connections used at microwave frequencies?

Select	Answer
A	To increase compensating capacitance
B	To reduce phase shift along the connection
C	To increase neutralizing resistance
D	To reduce noise figure

25. - E6A04

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

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

26. - E6B06

Which of the following is a common use of a Schottky diode?

Select	Answer
A	As a variable capacitance in an automatic frequency control circuit
B	As a constant voltage reference in a power supply
C	As a rectifier in high current power supplies
D	As a VHF/UHF mixer or detector

27. - E6C09

What is a Programmable Logic Device (PLD)?

Select	Answer
A	A programmable collection of logic gates and circuits in a single integrated circuit
B	Programmable equipment used for testing digital logic integrated circuits
C	A type of transistor whose gain can be changed by digital logic circuits
D	A logic circuit that can be modified during use

28. - E6D11

Which type of core material decreases inductance when inserted into a coil?

Select	Answer
A	Ceramic
B	Powdered iron
C	Brass
D	Ferrite

29. - E6E05

Which of the following noise figure values is typical of a low-noise UHF preamplifier?

Select	Answer
A	-10 dB
B	44 dBm
C	-20 dBm
D	2 dB

30. - E6F07

What is a solid-state relay?

Select	Answer
A	A relay using transistors to drive the relay coil
B	A semiconductor passive delay line
C	A device that uses semiconductors to implement the functions of an electromechanical relay
D	A mechanical relay that latches in the on or off state each time it is pulsed

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. - E7B04

Where on the load line of a Class A common emitter amplifier would bias normally be set?

Select	Answer
A	Approximately halfway between saturation and cutoff
B	At a point where the load line intersects the zero bias current curve
C	Where the load line intersects the voltage axis
D	At a point where the bias resistor equals the load resistor

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	Two capacitors are in series between the input and output, and an inductor is connected between the two capacitors and ground
B	Two inductors are in series between the input and output, and a capacitor is connected between the two inductors and ground
C	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
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. - E7D11

What is the function of the pass transistor in a linear voltage regulator circuit?

Select	Answer
A	Provides a stable input impedance over a wide range of source voltage
B	Maintains nearly constant output impedance over a wide range of load current
C	Maintains nearly constant output voltage over a wide range of load current
D	Permits a wide range of output voltage settings

35. - E7E04

What is one way a single-sideband phone signal can be generated?

Select	Answer
A	By driving a product detector with a DSB signal
B	By using a balanced modulator followed by a filter
C	By using a reactance modulator followed by a mixer
D	By using a loop modulator followed by a mixer

36. - E7F01

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

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

37. - E7G10

What absolute voltage gain can be expected from the circuit in Figure E7-3 when R1 is 1800 ohms and RF is 68 kilohms?

Select	Answer
A	0.03
B	76
C	38
D	1

38. - E7H08

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

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

39. - E8A08

Why would a direct or flash conversion analog-to-digital converter be useful for a software defined radio?

Select	Answer
A	Immunity to out-of-sequence coding reduces spurious responses
B	All these choices are correct
C	Very low power consumption decreases frequency drift
D	Very high speed allows digitizing high frequencies

40. - E8B04

What is the modulation index of an FM-phone signal having a maximum carrier deviation of plus or minus 6 kHz when modulated with a 2 kHz modulating frequency?

Select	Answer
A	2000
B	1/3
C	3
D	6000

41. - E8C07

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

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

42. - E8D03

How does the spread spectrum technique of frequency hopping work?

Select	Answer
A	If interference is detected by the receiver it will signal the transmitter to wait until the frequency is clear
B	A binary bit stream is used to shift the phase of an RF carrier very rapidly in a pseudorandom sequence
C	If interference is detected by the receiver it will signal the transmitter to change frequencies
D	The frequency of the transmitted signal is changed very rapidly according to a pseudorandom sequence also used by the receiving station

43. - E9A05

What is included in the total resistance of an antenna system?

Select	Answer
A	Radiation resistance plus transmission resistance
B	Transmission-line resistance plus radiation resistance
C	Radiation resistance plus loss resistance
D	Radiation resistance plus space impedance

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

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

46. - E9D04

Why should an HF mobile antenna loading coil have a high ratio of reactance to resistance?

Select	Answer
A	To minimize losses
B	To swamp out harmonics
C	To minimize the Q
D	To lower the radiation angle

47. - E9E01

What system matches a higher-impedance transmission line to a lower-impedance antenna by connecting the line to the driven element in two places spaced a fraction of a wavelength each side of element center?

Select	Answer
A	The gamma matching system
B	The omega matching system
C	The delta matching system
D	The stub matching system

48. - E9F11

What impedance does a 1/8-wavelength transmission line present to a generator when the line is open at the far end?

Select	Answer
A	The same as the characteristic impedance of the line
B	A capacitive reactance
C	Infinite
D	An inductive reactance

49. - E9G06

On the Smith chart shown in Figure E9-3, what is the name for the large outer circle on which the reactance arcs terminate?

Select	Answer
A	Prime axis
B	Impedance axis
C	Polar axis
D	Reactance axis

50. - E9H03

What is Receiving Directivity Factor (RDF)?

Select	Answer
A	Relative directivity compared to a dipole
B	Relative directivity compared to isotropic
C	Forward gain compared to the gain in the reverse direction
D	Forward gain compared to average gain over the entire hemisphere

Figure E7-3

Figure E9-3