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

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	14.070 MHz
B	14.100 MHz
C	14.149 MHz
D	14.349 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	15 kHz
B	3 kHz
C	20 kHz
D	10 kHz

4. - E1C14

How long must an operator wait after filing a notification with the Utilities Technology Council (UTC) before operating on the 2200 meter or 630 meter band?

Select	Answer
A	Operators must not operate until approval is received
B	Operators may operate after 30 days, providing they have not been told that their station is within 1 km of PLC systems using those frequencies
C	Operations may commence immediately, and may continue unless interference is reported by the UTC
D	Operators may not operate until a test signal has been transmitted in coordination with the local power company

5. - E1D04

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

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

6. - E1E01

For which types of out-of-pocket expenses do the Part 97 rules state that VEs and VECs may be reimbursed?

Select	Answer
A	Teaching an amateur operator license examination preparation course
B	No expenses are authorized for reimbursement
C	Providing amateur operator license examination preparation training materials
D	Preparing, processing, administering, and coordinating an examination for an amateur radio operator license

7. - E1F06

Under what circumstances might the FCC issue a Special Temporary Authority (STA) to an amateur station?

Select	Answer
A	To provide additional spectrum for personal use
B	To provide temporary operation while awaiting normal licensing
C	To allow regular operation on Land Mobile channels
D	To provide for experimental amateur communications

8. - E2A05

What do the letters in a satellite's mode designator specify?

Select	Answer
A	Power limits for uplink and downlink transmissions
B	The uplink and downlink frequency ranges
C	The location of the ground control station
D	The polarization of uplink and downlink signals

9. - E2B06

What is vestigial sideband modulation?

Select	Answer
A	Spread spectrum modulation achieved by applying FM modulation following single sideband amplitude modulation
B	Narrow-band FM modulation achieved by filtering one sideband from the audio before frequency modulating the carrier
C	Amplitude modulation in which one complete sideband and a portion of the other are transmitted
D	A type of modulation in which one sideband is inverted

10. - E2C08

Which of the following contacts may be confirmed through the U.S. QSL bureau system?

Select	Answer
A	Contacts between a U.S. station and a non-U.S. station
B	Contacts using tactical call signs
C	Special event contacts between stations in the U.S.
D	Repeater contacts between U.S. club members

11. - E2D09

What type of modulation is used for JT65 contacts?

Select	Answer
A	IEEE 802.11
B	Multi-tone AFSK
C	RTTY
D	PSK

12. - E2E11

What is the difference between direct FSK and audio FSK?

Select	Answer
A	Direct FSK applies the data signal to the transmitter VFO, while AFSK transmits tones via phone
B	Only direct FSK can be decoded by computer
C	Direct FSK can transmit faster baud rates
D	Direct FSK occupies less bandwidth

13. - E3A08

When a meteor strikes the Earth's atmosphere, a cylindrical region of free electrons is formed at what layer of the ionosphere?

Select	Answer
A	The D layer
B	The F2 layer
C	The F1 layer
D	The E layer

14. - E3B10

Why is chordal hop propagation desirable?

Select	Answer
A	Atmospheric noise is lower in the direction of chordal hop propagation
B	Signals travel faster along ionospheric chords
C	The MUF for chordal hop propagation is much lower than for normal skip propagation
D	The signal experiences less loss compared to multi-hop using Earth as a reflector

15. - E3C05

What orientation of Bz (B sub z) increases the likelihood that incoming particles from the sun will cause disturbed conditions?

Select	Answer
A	Westward
B	Southward
C	Northward
D	Eastward

16. - E4A10

Which of the following displays multiple digital signal states simultaneously?

Select	Answer
A	Bit error rate tester
B	Network analyzer
C	Logic analyzer
D	Modulation monitor

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 resonant frequency of the circuit
D	The inductance to capacitance ratio

18. - E4C04

What is the noise figure of a receiver?

Select	Answer
A	The ratio of thermal noise to atmospheric noise
B	The ratio of atmospheric noise to phase noise
C	The ratio of the noise bandwidth in hertz to the theoretical bandwidth of a resistive network
D	The ratio in dB of the noise generated by the receiver to the theoretical minimum noise

19. - E4D10

What does a third-order intercept level of 40 dBm mean with respect to receiver performance?

Select	Answer
A	A pair of 40 dBm input signals will theoretically generate a third-order intermodulation product that has the same output amplitude as either of the input signals
B	The receiver can tolerate signals up to 40 dB above the noise floor without producing third-order intermodulation products
C	Signals less than 40 dBm will not generate audible third-order intermodulation products
D	A pair of 1 mW input signals will produce a third-order intermodulation product that is 40 dB stronger than the input signal

20. - E4E08

What current flows equally on all conductors of an unshielded multi-conductor cable?

Select	Answer
A	Common-mode current
B	Reactive current only
C	Return current
D	Differential-mode current

21. - E5A14

What is the resonant frequency of an RLC circuit if R is 22 ohms, L is 50 microhenries and C is 40 picofarads?

Select	Answer
A	22.36 MHz
B	1.78 MHz
C	3.56 MHz
D	44.72 MHz

22. - E5B10

What is the relationship between the AC current through an inductor and the voltage across an inductor?

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

23. - E5C01

Which of the following represents capacitive reactance in rectangular notation?

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

25. - E6A02

Which of the following semiconductor materials contains excess free electrons?

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

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	Low junction capacitance
D	Ability to dissipate large amounts of power

27. - E6C01

What is the function of hysteresis in a comparator?

Select	Answer
A	To allow the comparator to be used with AC input signals
B	To cause the output to change states continually
C	To prevent input noise from causing unstable output signals
D	To increase the sensitivity

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. - E6E04

Which is the most common input and output impedance of circuits that use MMICs?

Select	Answer
A	300 ohms
B	450 ohms
C	50 ohms
D	10 ohms

30. - E6F07

What is a solid-state relay?

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

31. - E7A03

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

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

32. - E7B12

What type of amplifier circuit is shown in Figure E7-1?

Select	Answer
A	Common base
B	Common collector
C	Emitter follower
D	Common emitter

33. - E7C11

Which of the following describes a receiving filter's ability to reject signals occupying an adjacent channel?

Select	Answer
A	Noise factor
B	Shape factor
C	Phase response
D	Passband ripple

34. - E7D06

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

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

35. - E7E03

What is a frequency discriminator stage in a FM receiver?

Select	Answer
A	A circuit for filtering two closely adjacent signals
B	A circuit for detecting FM signals
C	An FM generator circuit
D	An automatic band-switching circuit

36. - E7F07

What function is performed by a Fast Fourier Transform?

Select	Answer
A	Converting analog signals to digital form
B	Converting digital signals from the time domain to the frequency domain
C	Converting 8-bit data to 16-bit data
D	Converting digital signals to analog form

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	94
B	0.21
C	47
D	24

38. - E7H04

How is positive feedback supplied in a Colpitts oscillator?

Select	Answer
A	Through a neutralizing capacitor
B	Through a capacitive divider
C	Through a tapped coil
D	Through link coupling

39. - E8A11

Which of the following is a measure of the quality of an analog-to-digital converter?

Select	Answer
A	Reciprocal mixing
B	Power factor
C	Total harmonic distortion
D	Peak envelope power

40. - E8B07

Orthogonal Frequency Division Multiplexing is a technique used for which type of amateur communication?

Select	Answer
A	Extremely low-power contacts
B	OFDM signals are not allowed on amateur bands
C	High-speed digital modes
D	EME

41. - E8C02

What is the definition of symbol rate in a digital transmission?

Select	Answer
A	The number of characters carried per second by the station-to-station link
B	The duration of each bit in a message sent over the air
C	The rate at which the waveform changes to convey information
D	The number of control characters in a message packet

42. - E8D09

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

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

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	1977 watts
B	420 watts
C	78.7 watts
D	286 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 distinct value of voltage across it
B	A wire is modeled as a series of segments, each having a uniform value of current
C	A wire is modeled as a single sine-wave current generator
D	A wire is modeled as a single sine-wave voltage source

45. - E9C06

What is the effect of adding a terminating resistor to a rhombic antenna?

Select	Answer
A	It decreases the ground loss
B	It changes the radiation pattern from bidirectional to unidirectional
C	It changes the radiation pattern from horizontal to vertical polarization
D	It reflects the standing waves on the antenna elements back to the transmitter

46. - E9D03

Where should a high Q loading coil be placed to minimize losses in a shortened vertical antenna?

Select	Answer
A	At a voltage node
B	Near the center of the vertical radiator
C	As close to the transmitter as possible
D	As low as possible on the vertical radiator

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	50 ohms
B	75 ohms
C	62 ohms
D	450 ohms

48. - E9F06

What is the approximate physical length of an air-insulated, parallel conductor transmission line that is electrically 1/2 wavelength long at 14.10 MHz?

Select	Answer
A	7.0 meters
B	10.6 meters
C	8.5 meters
D	13.3 meters

49. - E9G09

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

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

50. - E9H08

What is the function of a sense antenna?

Select	Answer
A	It provides diversity reception that cancels multipath signals
B	It increases the sensitivity of a DF antenna array
C	It allows DF antennas to receive signals at different vertical angles
D	It modifies the pattern of a DF antenna array to provide a null in one direction

Figure E7-1

Figure E7-2