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

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1. - E0A03

Over what range of frequencies are the FCC human body RF exposure limits most restrictive?

Select	Answer
A	300 to 3000 MHz
B	30 to 300 MHz
C	3 to 30 MHz
D	300 kHz to 3 MHz

2. - E1A07

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

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

3. - E1B08

What limitations may the FCC place on an amateur station if its signal causes interference to domestic broadcast reception, assuming that the receivers involved are of good engineering design?

Select	Answer
A	The amateur station must cease operation on all frequencies above 30 MHz
B	The amateur station must cease operation on all frequencies below 30 MHz
C	The amateur station must avoid transmitting during certain hours on frequencies that cause the interference
D	The amateur station must cease operation

4. - E1C05

When may an automatically controlled station originate third party communications?

Select	Answer
A	Only when transmitting RTTY or data emissions
B	When agreed upon by the sending or receiving station
C	When approved by the National Telecommunication and Information Administration
D	Never

5. - E1D04

Which of the following is required in the identification transmissions from a balloon-borne telemetry station?

Select	Answer
A	All these choices are correct
B	The output power of the balloon transmitter
C	Call sign
D	The station's six-character Maidenhead grid locator

6. - E1E03

What is a Volunteer Examiner Coordinator?

Select	Answer
A	The person who has entered into an agreement with the FCC to be the VE session manager
B	An organization that has entered into an agreement with the FCC to coordinate, prepare, and administer amateur operator license examinations
C	A person who has volunteered to prepare amateur operator license examinations
D	A person who has volunteered to administer amateur operator license examinations

7. - E1F01

On what frequencies are spread spectrum transmissions permitted?

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

8. - E2A01

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

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

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 provide vertical synchronization
C	To identify the call sign of the station transmitting
D	To identify the SSTV mode being used

10. - E2C03

From which of the following bands is amateur radio contesting generally excluded?

Select	Answer
A	30 meters
B	33 centimeters
C	2 meters
D	6 meters

11. - E2D03

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

Select	Answer
A	Olivia
B	MSK144
C	JT65
D	PACTOR III

12. - E2E06

What is the most common data rate used for HF packet?

Select	Answer
A	48 baud
B	110 baud
C	300 baud
D	1200 baud

13. - E3A01

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

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

14. - E3B04

What is meant by the terms "extraordinary" and "ordinary" waves?

Select	Answer
A	Long-path and short-path waves
B	Independent waves created in the ionosphere that are elliptically polarized
C	Extraordinary waves describe rare long-skip propagation compared to ordinary waves, which travel shorter distances
D	Refracted rays and reflected waves

15. - E3C04

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

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

16. - E4A06

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

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

17. - E4B03

Which S parameter is equivalent to forward gain?

Select	Answer
A	S12
B	S21
C	S11
D	S22

18. - E4C06

A CW receiver with the AGC off has an equivalent input noise power density of -174 dBm/Hz. What would be the level of an unmodulated carrier input to this receiver that would yield an audio output SNR of 0 dB in a 400 Hz noise bandwidth?

Select	Answer
A	-148 dBm
B	-155 dBm
C	-174 dBm
D	-164 dBm

19. - E4D09

What is the purpose of the preselector in a communications receiver?

Select	Answer
A	To allow selection of the optimum RF amplifier device
B	To increase rejection of signals outside the desired band
C	To store often-used frequencies
D	To provide a range of AGC time constants

20. - E4E07

Which of the following can cause shielded cables to radiate or receive interference?

Select	Answer
A	Tying all ground connections to a common point resulting in differential-mode currents in the shield
B	Low inductance ground connections at both ends of the shield
C	Common-mode currents on the shield and conductors
D	Use of braided shielding material

21. - E5A02

What is resonance in an LC or RLC circuit?

Select	Answer
A	The frequency at which the reactive impedance equals the resistive impedance
B	The frequency at which the capacitive reactance equals the inductive reactance
C	The highest frequency that will pass current
D	The lowest frequency that will pass current

22. - E5B12

What is admittance?

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

23. - E5C12

Which point on Figure E5-1 best represents the impedance of a series circuit consisting of a 300-ohm resistor and a 19-picofarad capacitor at 21.200 MHz?

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

24. - E5D03

What is microstrip?

Select	Answer
A	Lightweight transmission line made of common zip cord
B	Miniature coax used for low power applications
C	Precision printed circuit conductors above a ground plane that provide constant impedance interconnects at microwave frequencies
D	Short lengths of coax mounted on printed circuit boards to minimize time delay between microwave circuits

25. - E6A08

What term indicates the frequency at which the grounded-base current gain of a transistor has decreased to 0.7 of the gain obtainable at 1 kHz?

Select	Answer
A	Alpha rejection frequency
B	Corner frequency
C	Alpha cutoff frequency
D	Beta cutoff frequency

26. - E6B08

Which of the following is a Schottky barrier diode?

Select	Answer
A	Thermionic emission diode
B	Metal-semiconductor junction
C	Electrolytic rectifier
D	PIN junction

27. - E6C08

In Figure E6-3, what is the schematic symbol for a NAND gate?

Select	Answer
A	2
B	3
C	4
D	1

28. - E6D01

Why should core saturation of an impedance matching transformer be avoided?

Select	Answer
A	Harmonics and distortion could result
B	Magnetic flux would increase with frequency
C	RF susceptance would increase
D	Temporary changes of the core permeability could result

29. - E6E09

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

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

30. - E6F06

Which of these materials is most commonly used to create photoconductive devices?

Select	Answer
A	A heavy metal
B	An ordinary metal
C	A crystalline semiconductor
D	A liquid semiconductor

31. - E7A07

What logical operation does a NAND gate perform?

Select	Answer
A	It produces logic 1 at its output only when all inputs are logic 1
B	It produces logic 0 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. - E7B03

Which of the following components form the output of a class D amplifier circuit?

Select	Answer
A	A low-pass filter to remove switching signal components
B	A matched load resistor to prevent damage by switching transients
C	A high-pass filter to compensate for low gain at low frequencies
D	A temperature compensating load resistor to improve linearity

33. - E7C10

Which of the following filters would be the best choice for use in a 2 meter band repeater duplexer?

Select	Answer
A	A DSP filter
B	An L-C filter
C	A cavity filter
D	A crystal filter

34. - E7D13

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

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

35. - E7E06

Why is de-emphasis commonly used in FM communications receivers?

Select	Answer
A	To remove third-order distortion products
B	To reduce impulse noise reception
C	For higher efficiency
D	For compatibility with transmitters using phase modulation

36. - E7F04

What is a common method of generating an SSB signal using digital signal processing?

Select	Answer
A	Signals are combined in quadrature phase relationship
B	Mixing products are converted to voltages and subtracted by adder circuits
C	A frequency synthesizer removes the unwanted sidebands
D	Varying quartz crystal characteristics emulated in digital form

37. - E7G06

What is the gain-bandwidth of an operational amplifier?

Select	Answer
A	The frequency at which the amplifier's offset voltage is zero
B	The gain of the amplifier at a filter's cutoff frequency
C	The maximum frequency for a filter circuit using that type of amplifier
D	The frequency at which the open-loop gain of the amplifier equals one

38. - E7H11

What are the major spectral impurity components of direct digital synthesizers?

Select	Answer
A	Spurious signals at discrete frequencies
B	Nyquist limit noise
C	Digital conversion noise
D	Broadband noise

39. - E8A01

What is the name of the process that shows that a square wave is made up of a sine wave plus all its odd harmonics?

Select	Answer
A	Numerical analysis
B	Vector analysis
C	Differential analysis
D	Fourier analysis

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 increases as the RF carrier frequency increases
C	It does not depend on the RF carrier frequency
D	It decreases as the RF carrier frequency increases

41. - E8C11

What is the relationship between symbol rate and baud?

Select	Answer
A	Baud is twice the symbol rate
B	They are the same
C	Symbol rate is only used for packet-based modes
D	Baud is only used for RTTY

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. - E9A08

What is antenna bandwidth?

Select	Answer
A	The angle between the half-power radiation points
B	The frequency range over which an antenna satisfies a performance requirement
C	Antenna length divided by the number of elements
D	The angle formed between two imaginary lines drawn through the element ends

44. - E9B09

What type of computer program technique is commonly used for modeling antennas?

Select	Answer
A	Method of Moments
B	Graphical analysis
C	Calculus differentiation with respect to physical properties
D	Mutual impedance analysis

45. - E9C03

What is the radiation pattern of two 1/4-wavelength vertical antennas spaced 1/2-wavelength apart and fed in phase?

Select	Answer
A	A Figure-8 broadside to the axis of the array
B	Cardioid
C	A Figure-8 end-fire along the axis of the array
D	Omni-directional

46. - E9D02

How can linearly polarized Yagi antennas be used to produce circular polarization?

Select	Answer
A	Stack two Yagis fed 90 degrees out of phase to form an array with the respective elements in parallel planes
B	Arrange two Yagis perpendicular to each other with the driven elements at the same point on the boom fed 90 degrees out of phase
C	Arrange two Yagis collinear to each other with the driven elements fed 180 degrees out of phase
D	Stack two Yagis fed in phase to form an array with the respective elements in parallel planes

47. - E9E05

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

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

48. - E9F05

What is the approximate physical length of a solid polyethylene dielectric coaxial transmission line that is electrically 1/4 wavelength long at 14.1 MHz?

Select	Answer
A	5.3 meters
B	10.6 meters
C	4.3 meters
D	3.5 meters

49. - E9G08

What is the process of normalization with regard to a Smith chart?

Select	Answer
A	Reassigning impedance values with regard to the prime center
B	Reassigning resistance values with regard to the reactance axis
C	Reassigning reactance values with regard to the resistance axis
D	Reassigning prime center with regard to the reactance axis

50. - E9H02

Which is generally true for low band (160 meter and 80 meter) receiving antennas?

Select	Answer
A	They must be erected at least 1/2 wavelength above the ground to attain good directivity
B	Atmospheric noise is so high that gain over a dipole is not important
C	All these choices are correct
D	Low loss coax transmission line is essential for good performance

Figure E5-1

Figure E6-3