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	300 kHz to 3 MHz
C	3 to 30 MHz
D	30 to 300 MHz

2. - E1A12

What special operating frequency restrictions are imposed on slow scan TV transmissions?

Select	Answer
A	They are restricted to 7.245 MHz, 14.245 MHz, 21.345 MHz, and 28.945 MHz
B	They are restricted to phone band segments
C	They are not permitted above 54 MHz
D	None; they are allowed on all amateur frequencies

3. - E1B12

What must the control operator of a repeater operating in the 70 cm band do if a radiolocation system experiences interference from that repeater?

Select	Answer
A	Reduce the repeater antenna HAAT (Height Above Average Terrain)
B	File an FAA NOTAM (Notice to Airmen) with the repeater system's ERP, call sign, and six-character grid locator
C	All these choices are correct
D	Cease operation or make changes to the repeater to mitigate the interference

4. - E1C10

What is the permitted mean power of any spurious emission relative to the mean power of the fundamental emission from a station transmitter or external RF amplifier installed after January 1, 2003 and transmitting on a frequency below 30 MHz?

Select	Answer
A	At least 43 dB below
B	At least 63 dB below
C	At least 53 dB below
D	At least 73 dB below

5. - E1D09

Which UHF amateur bands have frequencies authorized for space stations?

Select	Answer
A	70 cm only
B	70 cm and 33 cm
C	33 cm and 13 cm
D	70 cm and 13 cm

6. - E1E03

What is a Volunteer Examiner Coordinator?

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

7. - E1F01

On what frequencies are spread spectrum transmissions permitted?

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

8. - E2A03

How is the signal inverted by an inverting linear transponder?

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

9. - E2B12

What signals SSTV receiving software to begin a new picture line?

Select	Answer
A	Specific tone frequencies
B	Specific tone amplitudes
C	A two-tone signal
D	Elapsed time

10. - E2C07

What is the Cabrillo format?

Select	Answer
A	A method of exchanging information during a contest QSO
B	A standard for submission of electronic contest logs
C	The most common set of contest rules
D	The rules of order for meetings between contest sponsors

11. - E2D04

What technology is used to track, in real time, balloons carrying amateur radio transmitters?

Select	Answer
A	Doppler shift of beacon signals
B	Ultrasonics
C	APRS
D	Bandwidth compressed LORAN

12. - E2E08

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

Select	Answer
A	RTTY
B	PACTOR
C	AMTOR
D	Hellschreiber

13. - E3A09

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

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

14. - E3B11

At what time of day can sporadic E propagation occur?

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

15. - E3C06

By how much does the VHF/UHF radio horizon distance exceed the geometric horizon?

Select	Answer
A	By approximately twice the distance
B	By approximately 15 percent of the distance
C	By approximately four times the distance
D	By approximately 50 percent of the distance

16. - E4A08

Which of the following measures SWR?

Select	Answer
A	A spectrum analyzer
B	A Q meter
C	An ohmmeter
D	An antenna analyzer

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 bandwidth of the circuit's frequency response
C	The inductance to capacitance ratio
D	The resonant frequency of the circuit

18. - E4C07

What does the MDS of a receiver represent?

Select	Answer
A	The meter display sensitivity
B	The maximum detectable spectrum
C	The minimum discernible signal
D	The multiplex distortion stability

19. - E4D04

Which of the following may reduce or eliminate intermodulation interference in a repeater caused by another transmitter operating in close proximity?

Select	Answer
A	A properly terminated circulator at the output of the repeater's transmitter
B	Utilizing a Class D final amplifier
C	A band-pass filter in the feed line between the transmitter and receiver
D	Utilizing a Class C final amplifier

20. - E4E07

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

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

21. - E5A10

How is the Q of an RLC series 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	Resistance divided by the reactance of either the inductance or capacitance
D	Reactance of either the inductance or capacitance multiplied by the resistance

22. - E5B11

What is the phase angle between the voltage across and the current through a series RLC circuit if XC is 25 ohms, R is 100 ohms, and XL is 50 ohms?

Select	Answer
A	76 degrees with the voltage lagging the current
B	14 degrees with the voltage lagging the current
C	76 degrees with the voltage leading the current
D	14 degrees with the voltage leading the current

23. - E5C10

Which point on Figure E5-1 best represents the impedance of a series circuit consisting of a 400-ohm resistor and a 38-picofarad capacitor at 14 MHz?

Select	Answer
A	Point 6
B	Point 2
C	Point 5
D	Point 4

24. - E5D13

How many watts are consumed in a circuit consisting of a 100-ohm resistor in series with a 100-ohm inductive reactance drawing 1 ampere?

Select	Answer
A	70.7 watts
B	200 watts
C	141.4 watts
D	100 watts

25. - E6A02

Which of the following semiconductor materials contains excess free electrons?

Select	Answer
A	P-type
B	Bipolar
C	N-type
D	Insulated gate

26. - E6B05

What characteristic of a PIN diode makes it useful as an RF switch?

Select	Answer
A	Extremely high reverse breakdown voltage
B	Reverse bias controls its forward voltage drop
C	Ability to dissipate large amounts of power
D	Low junction capacitance

27. - E6C03

What is tri-state logic?

Select	Answer
A	Logic devices that utilize ternary math
B	Low-power logic devices designed to operate at 3 volts
C	Logic devices with 0, 1, and high-impedance output states
D	Proprietary logic devices manufactured by Tri-State Devices

28. - E6D13

What is the primary cause of inductor self-resonance?

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

29. - E6E07

What type of transmission line is used for connections to MMICs?

Select	Answer
A	Miniature coax
B	Parallel wire
C	Microstrip
D	Circular waveguide

30. - E6F06

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

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

31. - E7A01

Which circuit is bistable?

Select	Answer
A	An AND gate
B	A bipolar amplifier
C	An OR gate
D	A flip-flop

32. - E7B15

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

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

33. - E7C09

What is a crystal lattice filter?

Select	Answer
A	A power supply filter made with interlaced quartz crystals
B	An audio filter made with four quartz crystals that resonate at 1 kHz intervals
C	A filter with narrow bandwidth and steep skirts made using quartz crystals
D	A filter using lattice-shaped quartz crystals for high-Q performance

34. - E7D06

What is the purpose of Q1 in the circuit shown in Figure E7-2?

Select	Answer
A	It provides a constant load for the voltage source
B	It provides negative feedback to improve regulation
C	It controls the current supplied to the load
D	It provides D1 with current

35. - E7E07

What is meant by the term "baseband" in radio communications?

Select	Answer
A	The lowest frequency band that the transmitter or receiver covers
B	The unmodulated bandwidth of the transmitted signal
C	The frequency range occupied by a message signal prior to modulation
D	The basic oscillator frequency in an FM transmitter that is multiplied to increase the deviation and carrier frequency

36. - E7F14

Which of the following would allow a digital signal processing filter to create a sharper filter response?

Select	Answer
A	Double-precision math routines
B	Higher data rate
C	More taps
D	Complex phasor representations

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	94
D	47

38. - E7H07

How can an oscillator's microphonic responses be reduced?

Select	Answer
A	Reduce noise on the oscillator's power supply
B	Use NP0 capacitors
C	Mechanically isolate the oscillator circuitry from its enclosure
D	Increase the bias voltage

39. - E8A07

What determines the PEP-to-average power ratio of a single-sideband phone signal?

Select	Answer
A	The degree of carrier suppression
B	Amplifier gain
C	The frequency of the modulating signal
D	Speech characteristics

40. - E8B03

What is the modulation index of an FM-phone signal having a maximum frequency deviation of 3000 Hz either side of the carrier frequency when the modulating frequency is 1000 Hz?

Select	Answer
A	0.3
B	3
C	1000
D	3000

41. - E8C10

How may data rate be increased without increasing bandwidth?

Select	Answer
A	It is impossible
B	Using forward error correction
C	Using a more efficient digital code
D	Increasing analog-to-digital conversion resolution

42. - E8D06

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

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

43. - E9A02

What is the effective radiated power relative to a dipole of a repeater station with 150 watts transmitter power output, 2 dB feed line loss, 2.2 dB duplexer loss, and 7 dBd antenna gain?

Select	Answer
A	420 watts
B	286 watts
C	78.7 watts
D	1977 watts

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

45. - E9C02

What is the radiation pattern of two 1/4-wavelength vertical antennas spaced 1/4 wavelength apart and fed 90 degrees out of phase?

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

46. - E9D12

Which of the following would provide the best RF ground for your station?

Select	Answer
A	An electrically short connection to 3 or 4 interconnected ground rods via a series RF choke
B	A 50-ohm resistor connected to ground
C	An electrically short connection to 3 or 4 interconnected ground rods driven into the Earth
D	An electrically short connection to a metal water pipe

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 inductive
C	The driven element reactance must be capacitive
D	The driven element resonance must be lower than the operating frequency

48. - E9F09

What is the approximate physical length of a foam polyethylene dielectric coaxial transmission line that is electrically 1/4 wavelength long at 7.2 MHz?

Select	Answer
A	6.9 meters
B	8.3 meters
C	10.4 meters
D	5.2 meters

49. - E9G10

What do the arcs on a Smith chart represent?

Select	Answer
A	Points with constant reactance
B	SWR
C	Points with constant resistance
D	Frequency

50. - E9H09

What is a Pennant antenna?

Select	Answer
A	A form of rhombic antenna terminated in a variable capacitor to provide frequency diversity
B	A stealth antenna built to look like a flagpole
C	A small, vertically oriented receiving antenna consisting of a triangular loop terminated in approximately 900 ohms
D	A four-element, high-gain vertical array invented by George Pennant

Figure E5-1

Figure E7-2