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

Logging in (or registering) will help the system to select questions that you need to focus on.

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	Any ordinary smoke detector can be used
C	Only with a carbon monoxide detector
D	By the odor

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	18.107 MHz
D	18.100 MHz

3. - E1B05

What is the National Radio Quiet Zone?

Select	Answer
A	An area in Florida surrounding Cape Canaveral
B	An area surrounding the National Radio Astronomy Observatory
C	An area in New Mexico surrounding the White Sands Test Area
D	An area in Puerto Rico surrounding the Arecibo Radio Telescope

4. - E1C03

How do the control operator responsibilities of a station under automatic control differ from one under local control?

Select	Answer
A	Under local control there is no control operator
B	Under automatic control there is no control operator
C	Under local control a control operator is not required to be present at a control point
D	Under automatic control the control operator is not required to be present at the control point

5. - E1D10

Which amateur stations are eligible to be telecommand stations of space stations (subject to the privileges of the class of operator license held by the control operator of the station)?

Select	Answer
A	Any amateur station so designated by the space station licensee
B	Any amateur station designated by NASA
C	Any amateur station so designated by the ITU
D	All these choices are correct

6. - E1E08

To which of the following examinees may a VE not administer an examination?

Select	Answer
A	Employees of the VE
B	Relatives of the VE as listed in the FCC rules
C	Friends of the VE
D	All these choices are correct

7. - E1F03

Under what circumstances may a dealer sell an external RF power amplifier capable of operation below 144 MHz if it has not been granted FCC certification?

Select	Answer
A	It was imported from a manufacturer in another country and was certificated by that country's government
B	It was purchased in used condition from an amateur operator and is sold to another amateur operator for use at that operator's station
C	The equipment dealer assembled it from a kit
D	It was imported from a manufacturer in a country that does not require certification of RF power amplifiers

8. - E2A12

What is the purpose of digital store-and-forward functions on an amateur radio satellite?

Select	Answer
A	To relay messages between satellites
B	To store digital messages in the satellite for later download by other stations
C	To upload operational software for the transponder
D	To delay download of telemetry between satellites

9. - E2B12

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

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

10. - E2C01

What indicator is required to be used by U.S.-licensed operators when operating a station via remote control and the remote transmitter is located in the U.S.?

Select	Answer
A	/R# where # is the district of the remote station
B	/ followed by the USPS two-letter abbreviation for the state in which the remote station is located
C	/ followed by the ARRL Section of the remote station
D	No additional indicator is required

11. - E2D02

Which of the following is a good technique for making meteor scatter contacts?

Select	Answer
A	Use of special digital modes
B	All these choices are correct
C	Short transmissions with rapidly repeated call signs and signal reports
D	15-second timed transmission sequences with stations alternating based on location

12. - E2E08

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

Select	Answer
A	PACTOR
B	Hellschreiber
C	AMTOR
D	RTTY

13. - E3A05

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

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

14. - E3B02

What is the approximate maximum range for signals using transequatorial propagation?

Select	Answer
A	7500 miles
B	1000 miles
C	5000 miles
D	2500 miles

15. - E3C07

Which of the following descriptors indicates the greatest solar flare intensity?

Select	Answer
A	Class X
B	Class B
C	Class M
D	Class A

16. - E4A05

What is the purpose of the prescaler function on a frequency counter?

Select	Answer
A	It amplifies low-level signals for more accurate counting
B	It multiplies a higher frequency signal so a low-frequency counter can display the operating frequency
C	It divides a higher frequency signal so a low-frequency counter can display the input frequency
D	It prevents oscillation in a low-frequency counter circuit

17. - E4B11

Which of the following can be measured with a vector network analyzer?

Select	Answer
A	Input impedance
B	All these choices are correct
C	Reflection coefficient
D	Output impedance

18. - E4C08

An SDR receiver is overloaded when input signals exceed what level?

Select	Answer
A	One-half the maximum sampling buffer size
B	The maximum count value of the analog-to-digital converter
C	One-half the maximum sample rate
D	The reference voltage of the analog-to-digital converter

19. - E4D12

What is the term for the reduction in receiver sensitivity caused by a strong signal near the received frequency?

Select	Answer
A	Squelch gain rollback
B	Quieting
C	Cross-modulation interference
D	Desensitization

20. - E4E10

What might be the cause of a loud roaring or buzzing AC line interference that comes and goes at intervals?

Select	Answer
A	A defective doorbell or doorbell transformer inside a nearby residence
B	A malfunctioning illuminated advertising display
C	Arcing contacts in a thermostatically controlled device
D	All these choices are correct

21. - E5A07

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

Select	Answer
A	R/L
B	Minimum
C	Maximum
D	L/R

22. - E5B03

How is impedance in polar form converted to an equivalent admittance?

Select	Answer
A	Square the magnitude and subtract 90 degrees from the angle
B	Take the square root of the magnitude and add 180 degrees to the angle
C	Take the reciprocal of the angle and change the sign of the magnitude
D	Take the reciprocal of the magnitude and change the sign of the angle

23. - E5C02

How are impedances described in polar coordinates?

Select	Answer
A	By phase angle and magnitude
B	By Y and G values
C	By X and R values
D	By real and imaginary parts

24. - E5D08

How many watts are consumed in a circuit having a power factor of 0.6 if the input is 200VAC at 5 amperes?

Select	Answer
A	600 watts
B	1600 watts
C	200 watts
D	1000 watts

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	Beta cutoff frequency
B	Alpha cutoff frequency
C	Alpha rejection frequency
D	Corner frequency

26. - E6B09

What is a common use for point-contact diodes?

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

27. - E6C03

What is tri-state logic?

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

28. - E6D02

What is the equivalent circuit of a quartz crystal?

Select	Answer
A	Motional capacitance, motional inductance, loss resistance, and a capacitor representing electrode and stray capacitance all in series
B	Motional capacitance, motional inductance, and loss resistance in series, all in parallel with a shunt capacitor representing electrode and stray capacitance
C	Motional capacitance, motional inductance, loss resistance, and a capacitor representing electrode and stray capacitance all in parallel
D	Motional inductance and loss resistance in series, paralleled with motional capacitance and a capacitor representing electrode and stray capacitance

29. - E6E02

Which of the following device packages is a through-hole type?

Select	Answer
A	SOT
B	DIP
C	PLCC
D	Ball grid array

30. - E6F01

What absorbs the energy from light falling on a photovoltaic cell?

Select	Answer
A	Electrons
B	Holes
C	Protons
D	Photons

31. - E7A09

What logical operation is performed by an exclusive NOR gate?

Select	Answer
A	It produces logic 0 at its output only if all inputs are logic 0
B	It produces logic 1 at its output only if all inputs are logic 1
C	It produces logic 0 at its output if only one input is logic 1
D	It produces logic 1 at its output if only one input is logic 1

32. - E7B15

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

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

33. - E7C05

Which filter type is described as having ripple in the passband and a sharp cutoff?

Select	Answer
A	A Butterworth filter
B	An active LC filter
C	A Chebyshev filter
D	A passive op-amp filter

34. - E7D02

What is a characteristic of a switching electronic voltage regulator?

Select	Answer
A	It is generally less efficient than a linear regulator
B	The resistance of a control element is varied in direct proportion to the line voltage or load current
C	The controlled device's duty cycle is changed to produce a constant average output voltage
D	It gives a ramp voltage at its output

35. - E7E02

What is the function of a reactance modulator?

Select	Answer
A	To produce PM or FM signals by using an electrically variable inductance or capacitance
B	To produce AM signals by using an electrically variable resistance
C	To produce PM signals by using an electrically variable resistance
D	To produce AM signals by using an electrically variable inductance or capacitance

36. - E7F06

What is the minimum number of bits required for an analog-to-digital converter to sample a signal with a range of 1 volt at a resolution of 1 millivolt?

Select	Answer
A	10 bits
B	4 bits
C	8 bits
D	6 bits

37. - E7G03

What is the typical input impedance of an op-amp?

Select	Answer
A	Very high
B	Very low
C	1000 ohms
D	100 ohms

38. - E7H11

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

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

39. - E8A07

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

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

40. - E8B11

What is digital time division multiplexing?

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

41. - E8C12

What factors affect the bandwidth of a transmitted CW signal?

Select	Answer
A	Keying speed and shape factor (rise and fall time)
B	IF bandwidth and Q
C	Modulation index and output power
D	All these choices are correct

42. - E8D04

What is the primary effect of extremely short rise or fall time on a CW signal?

Select	Answer
A	The generation of RF harmonics
B	The generation of key clicks
C	Limits data speed
D	More difficult to copy

43. - E9A09

What is antenna efficiency?

Select	Answer
A	Effective radiated power divided by transmitter output
B	Radiation resistance divided by transmission resistance
C	Radiation resistance divided by total resistance
D	Total resistance divided by radiation resistance

44. - E9B03

In the antenna radiation pattern shown in Figure E9-1, what is the front-to-side ratio?

Select	Answer
A	24 dB
B	12 dB
C	14 dB
D	18 dB

45. - E9C10

Which of the following describes a Zepp antenna?

Select	Answer
A	A vertical array capable of quickly changing the direction of maximum radiation by changing phasing lines
B	An end-fed dipole antenna
C	A dipole constructed from zip cord
D	An omni-directional antenna commonly used for satellite communications

46. - E9D10

What happens to feed-point impedance at the base of a fixed length HF mobile antenna when operated below its resonant frequency?

Select	Answer
A	The radiation resistance increases and the capacitive reactance increases
B	The radiation resistance decreases and the capacitive reactance decreases
C	The radiation resistance decreases and the capacitive reactance increases
D	The radiation resistance increases and the capacitive reactance decreases

47. - E9E11

What is the primary purpose of phasing lines when used with an antenna having multiple driven elements?

Select	Answer
A	It creates a low-angle radiation pattern
B	It prevents reflected power from traveling back down the feed line and causing harmonic radiation from the transmitter
C	It allows single-band antennas to operate on other bands
D	It ensures that each driven element operates in concert with the others to create the desired antenna pattern

48. - E9F13

What impedance does a 1/4-wavelength transmission line present to a generator when the line is shorted at the far end?

Select	Answer
A	The same as the characteristic impedance of the transmission line
B	Very low impedance
C	The same as the generator output impedance
D	Very high impedance

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	Standing wave ratio circles
C	Coaxial-length circles
D	Radiation-pattern circles

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	Low loss coax transmission line is essential for good performance
C	All these choices are correct
D	Atmospheric noise is so high that gain over a dipole is not important

Figure E9-1