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

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1. - E0A04

When evaluating a site with multiple transmitters operating at the same time, the operators and licensees of which transmitters are responsible for mitigating over-exposure situations?

Select	Answer
A	Only commercial transmitters
B	Only the most powerful transmitter
C	Each transmitter that produces 5 percent or more of its MPE limit in areas where the total MPE limit is exceeded.
D	Each transmitter operating with a duty cycle greater than 50 percent

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	18.068 MHz
B	18.110 MHz
C	18.100 MHz
D	18.107 MHz

3. - E1B01

Which of the following constitutes a spurious emission?

Select	Answer
A	A signal transmitted to prevent its detection by any station other than the intended recipient
B	An amateur station transmission made without the proper call sign identification
C	Any transmitted signal that unintentionally interferes with another licensed radio station
D	An emission outside the signal's necessary bandwidth that can be reduced or eliminated without affecting the information transmitted

4. - E1C05

When may an automatically controlled station originate third party communications?

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

5. - E1D01

What is the definition of telemetry?

Select	Answer
A	Two-way transmissions in excess of 1000 feet
B	Two-way transmissions of data
C	One-way transmission that initiates, modifies, or terminates the functions of a device at a distance
D	One-way transmission of measurements at a distance from the measuring instrument

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

7. - E1F09

Which of the following conditions apply when transmitting spread spectrum emissions?

Select	Answer
A	All these choices are correct
B	The transmission must not be used to obscure the meaning of any communication
C	A station transmitting SS emission must not cause harmful interference to other stations employing other authorized emissions
D	The transmitting station must be in an area regulated by the FCC or in a country that permits SS emissions

8. - E2A13

Which of the following techniques is normally used by low Earth orbiting digital satellites to relay messages around the world?

Select	Answer
A	Node hopping
B	Multi-satellite relaying
C	Store-and-forward
D	Digipeating

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 odd numbered lines in one field and even numbered lines in the next
C	By scanning lines from left to right in one field and right to left in the next
D	By scanning two fields simultaneously

10. - E2C12

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

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

11. - E2D01

Which of the following digital modes is designed for meteor scatter communications?

Select	Answer
A	APRS
B	MSK144
C	Hellschreiber
D	WSPR

12. - E2E13

Which of these digital modes has the fastest data throughput under clear communication conditions?

Select	Answer
A	PSK31
B	AMTOR
C	170 Hz shift, 45 baud RTTY
D	300 baud packet

13. - E3A02

What characterizes libration fading of an EME signal?

Select	Answer
A	A gradual loss of signal as the sun rises
B	A slow change in the pitch of the CW signal
C	A fluttery irregular fading
D	The returning echo is several hertz lower in frequency than the transmitted signal

14. - E3B03

What is the best time of day for transequatorial propagation?

Select	Answer
A	Late at night
B	Morning
C	Noon
D	Afternoon or early evening

15. - E3C13

What type of polarization is best for ground-wave propagation?

Select	Answer
A	Horizontal
B	Vertical
C	Circular
D	Elliptical

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	Antenna analyzers do not need an external RF source
C	Antenna analyzers display a time-varying representation of the modulation envelope
D	All these choices are correct

17. - E4B09

What is indicated if the current reading on an RF ammeter placed in series with the antenna feed line of a transmitter increases as the transmitter is tuned to resonance?

Select	Answer
A	There is more power going into the antenna
B	The transmitter is not properly neutralized
C	There is possibly a short to ground in the feed line
D	There is an impedance mismatch between the antenna and feed line

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

19. - E4D05

What transmitter frequencies would cause an intermodulation-product signal in a receiver tuned to 146.70 MHz when a nearby station transmits on 146.52 MHz?

Select	Answer
A	146.34 MHz and 146.61 MHz
B	146.10 MHz and 147.30 MHz
C	146.88 MHz and 146.34 MHz
D	173.35 MHz and 139.40 MHz

20. - E4E01

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

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

21. - E5A16

What is the resonant frequency of an RLC circuit if R is 33 ohms, L is 50 microhenries and C is 10 picofarads?

Select	Answer
A	7.12 kHz
B	23.5 kHz
C	7.12 MHz
D	23.5 MHz

22. - E5B04

What is the time constant of a circuit having two 220-microfarad capacitors and two 1-megohm resistors, all in parallel?

Select	Answer
A	55 seconds
B	110 seconds
C	220 seconds
D	440 seconds

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 1
C	Point 7
D	Point 3

24. - E5D14

What is reactive power?

Select	Answer
A	Power lost because of capacitor leakage
B	Power consumed in wire resistance in an inductor
C	Power consumed in circuit Q
D	Wattless, nonproductive power

25. - E6A09

What is a depletion-mode FET?

Select	Answer
A	Any FET without a channel
B	An FET that exhibits a current flow between source and drain when no gate voltage is applied
C	Any FET for which holes are the majority carriers
D	An FET that has no current flow between source and drain when no gate voltage is applied

26. - E6B09

What is a common use for point-contact diodes?

Select	Answer
A	As a constant voltage source
B	As an RF detector
C	As a high-voltage rectifier
D	As a constant current source

27. - E6C11

In Figure E6-3, what is the schematic symbol for the NOT operation (inverter)?

Select	Answer
A	5
B	4
C	6
D	2

28. - E6D11

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

Select	Answer
A	Powdered iron
B	Brass
C	Ferrite
D	Ceramic

29. - E6E12

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

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

30. - E6F09

What is the efficiency of a photovoltaic cell?

Select	Answer
A	The relative fraction of light that is converted to current
B	The output RF power divided by the input DC power
C	Cost per kilowatt-hour generated
D	The open-circuit voltage divided by the short-circuit current under full illumination

31. - E7A01

Which circuit is bistable?

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

32. - E7B10

In Figure E7-1, what is the purpose of R1 and R2?

Select	Answer
A	Load resistors
B	Self bias
C	Feedback
D	Voltage divider bias

33. - E7C04

How does an impedance-matching circuit transform a complex impedance to a resistive impedance?

Select	Answer
A	It introduces transconductance to cancel the reactive part of impedance
B	Reactive currents are dissipated in matched resistances
C	It cancels the reactive part of the impedance and changes the resistive part to a desired value
D	It introduces negative resistance to cancel the resistive part of impedance

34. - E7D05

Which of the following types of linear voltage regulator places a constant load on the unregulated voltage source?

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

35. - E7E04

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

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

36. - E7F13

What is the function of taps in a digital signal processing filter?

Select	Answer
A	Provide incremental signal delays for filter algorithms
B	To reduce excess signal pressure levels
C	Select the point at which baseband signals are generated
D	Provide access for debugging software

37. - E7G05

How can unwanted ringing and audio instability be prevented in an op-amp RC audio filter circuit?

Select	Answer
A	Restrict Q but increase gain
B	Restrict gain but increase Q
C	Increase both gain and Q
D	Restrict both gain and Q

38. - E7H08

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

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

39. - E8A09

How many different input levels can be encoded by an analog-to-digital converter with 8-bit resolution?

Select	Answer
A	8
B	256
C	256 divided by the gain of the input amplifier
D	8 multiplied by the gain of the input amplifier

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	1000
B	3
C	0.3
D	3000

41. - E8C07

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

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

42. - E8D07

What is a common cause of overmodulation of AFSK signals?

Select	Answer
A	Ground loops
B	Excessive transmit audio levels
C	Excessive numbers of retries
D	Bit errors in the modem

43. - E9A08

What is antenna bandwidth?

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

44. - E9B11

What is a disadvantage of decreasing the number of wire segments in an antenna model below 10 segments per half-wavelength?

Select	Answer
A	Ground conductivity will not be accurately modeled
B	The antenna will become mechanically unstable
C	The resulting design will favor radiation of harmonic energy
D	The computed feed point impedance may be incorrect

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. - E9D06

What happens to the SWR bandwidth when one or more loading coils are used to resonate an electrically short antenna?

Select	Answer
A	It is increased
B	It is unchanged if the loading coil is located at the feed point
C	It is unchanged if the loading coil is located at a voltage maximum point
D	It is decreased

47. - E9E07

What parameter describes the interactions at the load end of a mismatched transmission line?

Select	Answer
A	Dielectric constant
B	Characteristic impedance
C	Reflection coefficient
D	Velocity factor

48. - E9F02

Which of the following has the biggest effect on the velocity factor of a transmission line?

Select	Answer
A	The termination impedance
B	The center conductor resistivity
C	Dielectric materials used in the line
D	The line length

49. - E9G07

On the Smith chart shown in Figure E9-3, what is the only straight line shown?

Select	Answer
A	The resistance axis
B	The current axis
C	The voltage axis
D	The reactance axis

50. - E9H07

Why is RF attenuation used when direction-finding?

Select	Answer
A	To prevent receiver overload which reduces pattern nulls
B	To narrow the receiver bandwidth
C	To compensate for isotropic directivity and the antenna effect of feed lines
D	To increase receiver sensitivity

Figure E5-1

Figure E6-3

Figure E7-1

Figure E9-3