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

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1. - E0A09

Which insulating material commonly used as a thermal conductor for some types of electronic devices is extremely toxic if broken or crushed and the particles are accidentally inhaled?

Select	Answer
A	Mica
B	Uranium Hexafluoride
C	Beryllium Oxide
D	Zinc oxide

2. - E1A12

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

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

3. - E1B05

What is the National Radio Quiet Zone?

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

4. - E1C13

What notifications must be given before transmitting on the 630 meter or 2200 meter bands?

Select	Answer
A	An environmental impact statement must be filed with the Department of the Interior
B	A special endorsement must be requested from the FCC
C	Operators must inform the Utilities Technology Council (UTC) of their call sign and coordinates of the station
D	Operators must inform the FAA of their intent to operate, giving their call sign and distance to the nearest runway

5. - E1D12

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

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

6. - E1E07

What should a VE do if a candidate fails to comply with the examiner's instructions during an amateur operator license examination?

Select	Answer
A	Allow the candidate to complete the examination, but invalidate the results
B	Immediately terminate everyone's examination and close the session
C	Warn the candidate that continued failure to comply will result in termination of the examination
D	Immediately terminate the candidate's examination

7. - E1F07

When may an amateur station send a message to a business?

Select	Answer
A	When neither the amateur nor his or her employer has a pecuniary interest in the communications
B	When transmitting international third-party communications
C	When the control operator is employed by the FCC or another government agency
D	When the total money involved does not exceed $25

8. - E2A07

Which of the following types of signals can be relayed through a linear transponder?

Select	Answer
A	All these choices are correct
B	FM and CW
C	SSB and SSTV
D	PSK and packet

9. - E2B08

What technique allows commercial analog TV receivers to be used for fast-scan TV operations on the 70 cm band?

Select	Answer
A	Using USB and demodulating the signal with a computer sound card
B	Using converted satellite TV dishes
C	Transmitting on the abandoned TV channel 2
D	Transmitting on channels shared with cable TV

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. - E2D10

How can an APRS station be used to help support a public service communications activity?

Select	Answer
A	An APRS station with an emergency medical technician can automatically transmit medical data to the nearest hospital
B	An APRS station with a Global Positioning System unit can automatically transmit information to show a mobile station's position during the event
C	APRS stations with General Personnel Scanners can automatically relay the participant numbers and time as they pass the check points
D	All these choices are correct

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	One of the signal filters is saturated
C	The mark and space signal have been inverted
D	The receiver has drifted 5 kHz from the desired receive frequency

13. - E3A05

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

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

14. - E3B06

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

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

15. - E3C01

What does the radio communication term "ray tracing" describe?

Select	Answer
A	Determining the radiation pattern from an array of antennas
B	Modeling a radio wave's path through the ionosphere
C	Evaluating high voltage sources for x-rays
D	The process in which an electronic display presents a pattern

16. - E4A02

Which of the following parameters does a spectrum analyzer display on the vertical and horizontal axes?

Select	Answer
A	RF amplitude and time
B	SWR and time
C	SWR and frequency
D	RF amplitude and frequency

17. - E4B01

Which of the following factors most affects the accuracy of a frequency counter?

Select	Answer
A	Temperature coefficient of the logic
B	Time base accuracy
C	Decade divider accuracy
D	Input attenuator accuracy

18. - E4C04

What is the noise figure of a receiver?

Select	Answer
A	The ratio of atmospheric noise to phase noise
B	The ratio of thermal noise to atmospheric 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. - E4D12

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

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

20. - E4E01

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

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

21. - E5A05

What is the result of increasing the Q of an impedance-matching circuit?

Select	Answer
A	Matching range is increased
B	Matching bandwidth is decreased
C	Matching bandwidth is increased
D	It has no effect on impedance matching

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	440 seconds
C	220 seconds
D	110 seconds

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 2
B	Point 4
C	Point 6
D	Point 5

24. - E5D03

What is microstrip?

Select	Answer
A	Precision printed circuit conductors above a ground plane that provide constant impedance interconnects at microwave frequencies
B	Lightweight transmission line made of common zip cord
C	Miniature coax used for low power applications
D	Short lengths of coax mounted on printed circuit boards to minimize time delay between microwave circuits

25. - E6A03

Why does a PN-junction diode not conduct current when reverse biased?

Select	Answer
A	Only N-type semiconductor material can conduct current
B	Excess holes in P-type material combine with the electrons in N-type material, converting the entire diode into an insulator
C	Holes in P-type material and electrons in the N-type material are separated by the applied voltage, widening the depletion region
D	Only P-type semiconductor material can conduct current

26. - E6B11

What is used to control the attenuation of RF signals by a PIN diode?

Select	Answer
A	Reverse voltage larger than the RF signal
B	Capacitance of an RF coupling capacitor
C	A sub-harmonic pump signal
D	Forward DC bias current

27. - E6C05

What is an advantage of CMOS logic devices over TTL devices?

Select	Answer
A	Lower power consumption
B	Immune to damage from static discharge
C	Lower distortion
D	Differential output capability

28. - E6D12

What is inductor saturation?

Select	Answer
A	The ability of the inductor's core to store magnetic energy has been exceeded
B	The inductor's voltage rating is exceeded causing a flashover
C	The inductor windings are over-coupled
D	Adjacent inductors become over-coupled

29. - E6E03

Which of the following materials is likely to provide the highest frequency of operation when used in MMICs?

Select	Answer
A	Gallium nitride
B	Silicon
C	Silicon nitride
D	Silicon dioxide

30. - E6F02

What happens to the conductivity of a photoconductive material when light shines on it?

Select	Answer
A	It becomes unstable
B	It stays the same
C	It increases
D	It decreases

31. - E7A06

What is a characteristic of a monostable multivibrator?

Select	Answer
A	It maintains a constant output voltage, regardless of variations in the input voltage
B	It switches momentarily to the opposite binary state and then returns to its original state after a set time
C	It stores one bit of data in either a 0 or 1 state
D	It produces a continuous square wave oscillating between 1 and 0

32. - E7B18

What is a characteristic of a grounded-grid amplifier?

Select	Answer
A	High filament voltage
B	High power gain
C	Low input impedance
D	Low bandwidth

33. - E7C12

What is one advantage of a Pi-matching network over an L-matching network consisting of a single inductor and a single capacitor?

Select	Answer
A	L-networks cannot perform impedance transformation
B	Pi-networks provide balanced input and output
C	The Q of Pi-networks can be controlled
D	Pi-networks are more stable

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 negative feedback to improve regulation
C	It provides D1 with current
D	It provides a constant load for the voltage source

35. - E7E07

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

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

36. - E7F04

What is a common method of generating an SSB signal using digital signal processing?

Select	Answer
A	Mixing products are converted to voltages and subtracted by adder circuits
B	A frequency synthesizer removes the unwanted sidebands
C	Signals are combined in quadrature phase relationship
D	Varying quartz crystal characteristics emulated in digital form

37. - E7G03

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

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

38. - E7H15

Which of these functions can be performed by a phase-locked loop?

Select	Answer
A	Photovoltaic conversion, optical coupling
B	Comparison of two digital input signals, digital pulse counter
C	Frequency synthesis, FM demodulation
D	Wide-band AF and RF power amplification

39. - E8A11

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

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

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 data streams share the same channel by transmitting time of transmission as the sub-carrier
D	Two or more signals are arranged to share discrete time slots of a data transmission

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	All these choices are correct
C	IF bandwidth and Q
D	Modulation index and output power

42. - E8D05

What is the most common method of reducing key clicks?

Select	Answer
A	Reduce keying waveform rise and fall times
B	Increase keying waveform rise and fall times
C	High-pass filters at the transmitter output
D	Low-pass filters at the transmitter output

43. - E9A07

What is the effective isotropic radiated power of a repeater station with 200 watts transmitter power output, 2 dB feed line loss, 2.8 dB duplexer loss, 1.2 dB circulator loss, and 7 dBi antenna gain?

Select	Answer
A	159 watts
B	632 watts
C	252 watts
D	63.2 watts

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

45. - E9C06

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

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

46. - E9D03

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

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

47. - E9E09

Which of the following is used to shunt-feed a grounded tower at its base?

Select	Answer
A	All these choices are correct
B	Double-bazooka match
C	Hairpin match
D	Gamma match

48. - E9F02

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

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

49. - E9G11

How are the wavelength scales on a Smith chart calibrated?

Select	Answer
A	In fractions of antenna electrical frequency
B	In fractions of transmission line electrical frequency
C	In fractions of antenna electrical wavelength
D	In fractions of transmission line electrical wavelength

50. - E9H02

Which is generally true for low band (160 meter and 80 meter) receiving antennas?

Select	Answer
A	Low loss coax transmission line is essential for good performance
B	They must be erected at least 1/2 wavelength above the ground to attain good directivity
C	All these choices are correct
D	Atmospheric noise is so high that gain over a dipole is not important

Figure E5-1

Figure E7-2