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

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1. - E0A07

How may dangerous levels of carbon monoxide from an emergency generator be detected?

Select	Answer
A	By the yellowish appearance of the gas
B	Only with a carbon monoxide detector
C	By the odor
D	Any ordinary smoke detector can be used

2. - E1A01

Which of the following carrier frequencies is illegal for LSB AFSK emissions on the 17 meter band RTTY and data segment of 18.068 to 18.110 MHz?

Select	Answer
A	18.107 MHz
B	18.068 MHz
C	18.100 MHz
D	18.110 MHz

3. - E1B02

Which of the following is an acceptable bandwidth for Digital Radio Mondiale (DRM) based voice or SSTV digital transmissions made on the HF amateur bands?

Select	Answer
A	10 kHz
B	20 kHz
C	15 kHz
D	3 kHz

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 53 dB below
B	At least 73 dB below
C	At least 63 dB below
D	At least 43 dB below

5. - E1D12

Which of the following amateur stations may transmit one-way communications?

Select	Answer
A	A message forwarding station or automatically controlled digital station
B	A local repeater or linked repeater station
C	A space station, beacon station, or telecommand station
D	All these choices are correct

6. - E1E02

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

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

7. - E1F02

What privileges are authorized in the U.S. to persons holding an amateur service license granted by the government of Canada?

Select	Answer
A	The operating terms and conditions of the Canadian amateur service license, not to exceed U.S. Amateur Extra Class license privileges
B	None, they must obtain a U.S. license
C	All privileges of the Amateur Extra Class license
D	Full privileges, up to and including those of the Amateur Extra Class license, on the 80, 40, 20, 15, and 10 meter bands

8. - E2A04

What is meant by the term mode? as applied to an amateur radio satellite?

Select	Answer
A	Whether the satellite is in a low earth or geostationary orbit
B	The satellite's orientation with respect to the Earth
C	Whether the satellite is in a polar or equatorial orbit
D	The satellite's uplink and downlink frequency bands

9. - E2B10

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

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

10. - E2C05

What is the function of a DX QSL Manager?

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

11. - E2D05

What is one advantage of the JT65 mode?

Select	Answer
A	The ability to decode signals which have a very low signal-to-noise ratio
B	Permits fast-scan TV transmissions over narrow bandwidth
C	Uses only a 65 Hz bandwidth
D	Easily copied by ear if necessary

12. - E2E04

What is indicated when one of the ellipses in an FSK crossed-ellipse display suddenly disappears?

Select	Answer
A	Selective fading has occurred
B	The mark and space signal have been inverted
C	The receiver has drifted 5 kHz from the desired receive frequency
D	One of the signal filters is saturated

13. - E3A05

Tropospheric propagation of microwave signals often occurs in association with what phenomenon?

Select	Answer
A	Grayline
B	Warm and cold fronts
C	Lightning discharges
D	Sprites and jets

14. - E3B06

Which of the following amateur bands most frequently provides long-path propagation?

Select	Answer
A	80 meters
B	20 meters
C	6 meters
D	10 meters

15. - E3C06

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

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

16. - E4A09

Which of the following is good practice when using an oscilloscope probe?

Select	Answer
A	Never use a high-impedance probe to measure a low-impedance circuit
B	All these choices are correct
C	Keep the signal ground connection of the probe as short as possible
D	Never use a DC-coupled probe to measure an AC circuit

17. - E4B04

Which S parameter represents input port return loss or reflection coefficient (equivalent to VSWR)?

Select	Answer
A	S11
B	S22
C	S21
D	S12

18. - E4C07

What does the MDS of a receiver represent?

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

19. - E4D07

Which of the following reduces the likelihood of receiver desensitization?

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

20. - E4E01

What problem can occur when using an automatic notch filter (ANF) to remove interfering carriers while receiving CW signals?

Select	Answer
A	Removal of the CW signal as well as the interfering carrier
B	Ringing in the DSP filter will completely remove the spaces between the CW characters
C	Any nearby signal passing through the DSP system will overwhelm the desired signal
D	Received CW signals will appear to be modulated at the DSP clock frequency

21. - E5A04

What is the magnitude of the impedance of a parallel RLC circuit at resonance?

Select	Answer
A	Approximately equal to inductive reactance
B	Low compared to the circuit resistance
C	High compared to the circuit resistance
D	Approximately equal to circuit resistance

22. - E5B09

What is the relationship between the AC current through a capacitor and the voltage across a capacitor?

Select	Answer
A	Voltage and current are 180 degrees out of phase
B	Voltage leads current by 90 degrees
C	Voltage and current are in phase
D	Current leads voltage by 90 degrees

23. - E5C05

What is the name of the diagram used to show the phase relationship between impedances at a given frequency?

Select	Answer
A	Near field diagram
B	Far field diagram
C	Venn diagram
D	Phasor diagram

24. - E5D11

What is the power factor of an RL circuit having a 60-degree phase angle between the voltage and the current?

Select	Answer
A	0.5
B	1.414
C	1.73
D	0.866

25. - E6A04

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

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

26. - E6B05

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

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

27. - E6C06

Why do CMOS digital integrated circuits have high immunity to noise on the input signal or power supply?

Select	Answer
A	Large bypass capacitance is inherent
B	Bandwidth is very limited
C	The input switching threshold is about one-half the power supply voltage
D	The input switching threshold is about two times the power supply voltage

28. - E6D11

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

Select	Answer
A	Ferrite
B	Ceramic
C	Brass
D	Powdered iron

29. - E6E12

Why are DIP through-hole package ICs not typically used at UHF and higher frequencies?

Select	Answer
A	Excessive lead length
B	Epoxy coating is conductive above 300 MHz
C	Unsuitable for combining analog and digital signals
D	Too many pins

30. - E6F08

Why are optoisolators often used in conjunction with solid-state circuits when switching 120 VAC?

Select	Answer
A	Optoisolators provide impedance matching between the control circuit and power circuit
B	Optoisolators provide a very high degree of electrical isolation between a control circuit and the circuit being switched
C	Optoisolators eliminate the effects of reflected light in the control circuit
D	Optoisolators provide a low impedance link between a control circuit and a power circuit

31. - E7A03

Which of the following can divide the frequency of a pulse train by 2?

Select	Answer
A	An XOR gate
B	An OR gate
C	A multiplexer
D	A flip-flop

32. - E7B08

How can an RF power amplifier be neutralized?

Select	Answer
A	By feeding a 180-degree out-of-phase portion of the output back to the input
B	By feeding an in-phase component of the output back to the input
C	By reducing the driving power
D	By increasing the driving power

33. - E7C07

Which describes a Pi-L-network used for matching a vacuum tube final amplifier to a 50-ohm unbalanced output?

Select	Answer
A	A matching network in which all components are isolated from ground
B	A Pi-network with an additional series inductor on the output
C	A network with only three discrete parts
D	A Phase Inverter Load network

34. - E7D04

Which of the following types of linear voltage regulator usually make the most efficient use of the primary power source?

Select	Answer
A	A shunt current source
B	A shunt regulator
C	A series regulator
D	A series current source

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 reactance modulator followed by a mixer
C	By using a balanced modulator followed by a filter
D	By using a loop modulator followed by a mixer

36. - E7F09

Why is an anti-aliasing digital filter required in a digital decimator?

Select	Answer
A	It notches out the sampling frequency to avoid sampling errors
B	It removes high-frequency signal components that would otherwise be reproduced as lower frequency components
C	It removes low-frequency signal components to eliminate the need for DC restoration
D	It peaks the response of the decimator, improving bandwidth

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	38
B	0.03
C	1
D	76

38. - E7H14

What is a phase-locked loop circuit?

Select	Answer
A	An electronic circuit consisting of a precision push-pull amplifier with a differential input
B	An electronic servo loop consisting of a phase detector, a low-pass filter, a voltage-controlled oscillator, and a stable reference oscillator
C	An electronic circuit also known as a monostable multivibrator
D	An electronic servo loop consisting of a ratio detector, reactance modulator, and voltage-controlled oscillator

39. - E8A06

What is the approximate ratio of PEP-to-average power in a typical single-sideband phone signal?

Select	Answer
A	100 to 1
B	2.5 to 1
C	25 to 1
D	1 to 1

40. - E8B11

What is digital time division multiplexing?

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

41. - E8C05

What is the approximate bandwidth of a 13-WPM International Morse Code transmission?

Select	Answer
A	52 Hz
B	104 Hz
C	26 Hz
D	13 Hz

42. - E8D10

What are some of the differences between the Baudot digital code and ASCII?

Select	Answer
A	Baudot uses 6 data bits per character, ASCII uses 7 or 8; Baudot has no letters/figures shift code, ASCII uses 2 letters/figures shift codes
B	Baudot uses 7 data bits per character, ASCII uses 8; Baudot has no letters/figures shift code, ASCII uses 2 letters/figures shift codes
C	Baudot uses 5 data bits per character, ASCII uses 7 or 8; Baudot uses 2 characters as letters/figures shift codes, ASCII has no letters/figures shift code
D	Baudot uses 4 data bits per character, ASCII uses 7 or 8; Baudot uses 1 character as a letters/figures shift code, ASCII has no letters/figures code

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	78.7 watts
B	286 watts
C	1977 watts
D	420 watts

44. - E9B09

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

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

45. - E9C08

What is a folded dipole antenna?

Select	Answer
A	A half-wave dipole with an additional parallel wire connecting its two ends
B	A dipole one-quarter wavelength long
C	A dipole configured to provide forward gain
D	A type of ground-plane antenna

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 lower the radiation angle
D	To minimize the Q

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	75 ohms
B	62 ohms
C	450 ohms
D	50 ohms

48. - E9F07

How does ladder line compare to small-diameter coaxial cable such as RG-58 at 50 MHz?

Select	Answer
A	Lower velocity factor
B	Higher SWR
C	Lower loss
D	Smaller reflection coefficient

49. - E9G09

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

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

50. - E9H05

What is the main drawback of a small wire-loop antenna for direction finding?

Select	Answer
A	It is practical for use only on VHF and higher bands
B	All these choices are correct
C	It has no clearly defined null
D	It has a bidirectional pattern

Figure E7-3