US Amateur Radio - Amateur Extra (Element 4, 2016-2020) Practice Test

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

1. - E1A06

Where must the carrier frequency of a CW signal be set to comply with FCC rules for 60 meter operation?

Select	Answer
A	On any frequency where the signal's sidebands are within the channel
B	At the center frequency of the channel
C	At the lowest frequency of the channel
D	At the highest frequency of the channel

2. - E1B10

What frequencies are authorized to an amateur station operating under RACES rules?

Select	Answer
A	All amateur service frequencies authorized to the control operator
B	Military Auxiliary Radio System (MARS) channels
C	Specific local government channels
D	Specific segments in the amateur service MF, HF, VHF and UHF bands

3. - E1C10

What types of amateur stations may automatically retransmit the radio signals of other amateur stations?

Select	Answer
A	Only earth stations, repeater stations or model craft
B	Only beacon, repeater or space stations
C	Only auxiliary, repeater or space stations
D	Only auxiliary, beacon or space stations

4. - E1D08

Which VHF amateur service bands have frequencies available for space stations?

Select	Answer
A	6 meters, 2 meters, and 1.25 meters
B	2 meters and 1.25 meters
C	6 meters and 2 meters
D	2 meters

5. - E1E05

What is the minimum passing score on amateur operator license examinations?

Select	Answer
A	Minimum passing score of 77%
B	Minimum passing score of 70%
C	Minimum passing score of 80%
D	Minimum passing score of 74%

6. - E1F06

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

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

7. - E2A06

On what band would a satellite receive signals if it were operating in mode U/V?

Select	Answer
A	50.0 MHz - 50.2 MHz
B	435 MHz - 438 MHz
C	29.5 MHz - 29.7 MHz
D	144 MHz - 146 MHz

8. - E2B05

Which of the following is an advantage of using vestigial sideband for standard fast- scan TV transmissions?

Select	Answer
A	The vestigial sideband contains chroma information
B	The vestigial sideband carries the audio information
C	Vestigial sideband reduces bandwidth while allowing for simple video detector circuitry
D	Vestigial sideband provides high frequency emphasis to sharpen the picture

9. - E2C12

What might help to restore contact when DX signals become too weak to copy across an entire HF band a few hours after sunset?

Select	Answer
A	Wait 90 minutes or so for the signal degradation to pass
B	Switch to a lower frequency HF band
C	Wait 24 hours before attempting another communication on the band
D	Switch to a higher frequency HF band

10. - E2D13

What type of modulation is used for JT65 contacts?

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

11. - E2E10

Which of these digital modes has the narrowest bandwidth?

Select	Answer
A	300-baud packet
B	PSK31
C	170 Hz shift, 45 baud RTTY
D	MFSK16

12. - E3A11

What is a typical range for tropospheric propagation of microwave signals?

Select	Answer
A	10 miles to 50 miles
B	100 miles to 300 miles
C	1200 miles
D	2500 miles

13. - E3B14

What happens to linearly polarized radio waves that split into ordinary and extraordinary waves in the ionosphere?

Select	Answer
A	They become elliptically polarized
B	Their polarization is randomly modified
C	They are bent toward the magnetic poles
D	They become phase-locked

14. - E3C15

What might a sudden rise in radio background noise indicate?

Select	Answer
A	Increased transequatorial propagation likely
B	Long-path propagation is occurring
C	A meteor ping
D	A solar flare has occurred

15. - E4A02

Which of the following parameters would 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

16. - E4B06

How much power is being absorbed by the load when a directional power meter connected between a transmitter and a terminating load reads 100 watts forward power and 25 watts reflected power?

Select	Answer
A	100 watts
B	125 watts
C	75 watts
D	25 watts

17. - E4C11

Which of the following is a desirable amount of selectivity for an amateur SSB phone receiver?

Select	Answer
A	2.4 kHz
B	1 kHz
C	4.2 kHz
D	4.8 kHz

18. - E4D09

What is the purpose of the preselector in a communications receiver?

Select	Answer
A	To provide a range of AGC time constants
B	To store often-used frequencies
C	To increase rejection of unwanted signals
D	To allow selection of the optimum RF amplifier device

19. - E4E16

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

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

20. - E5A03

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

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

21. - E5B11

What is the phase angle between the voltage across and the current through a series RLC circuit if XC is 25 ohms, R is 100 ohms, and XL is 50 ohms?

Select	Answer
A	14 degrees with the voltage leading the current
B	14 degrees with the voltage lagging the current
C	76 degrees with the voltage leading the current
D	76 degrees with the voltage lagging the current

22. - E5C04

Which of the following represents a capacitive reactance in polar coordinates?

Select	Answer
A	A negative real part
B	A positive real part
C	A positive phase angle
D	A negative phase angle

23. - E5D10

How can the true power be determined in an AC circuit where the voltage and current are out of phase?

Select	Answer
A	By dividing the reactive power by the power factor
B	By multiplying the reactive power times the power factor
C	By multiplying the apparent power times the power factor
D	By dividing the apparent power by the power factor

24. - E6A05

What is the alpha of a bipolar junction transistor?

Select	Answer
A	The change of base current with respect to collector current
B	The change of collector current with respect to emitter current
C	The change of collector current with respect to gate current
D	The change of collector current with respect to base current

25. - E6B04

What type of semiconductor device is designed for use as a voltage-controlled capacitor?

Select	Answer
A	Zener diode
B	Varactor diode
C	Silicon-controlled rectifier
D	Tunnel diode

26. - E6C05

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

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

27. - E6D01

How many turns will be required to produce a 5-microhenry inductor using a powdered-iron toroidal core that has an inductance index (A L) value of 40 microhenrys/100 turns?

Select	Answer
A	35 turns
B	141 turns
C	79 turns
D	13 turns

28. - E6E12

Why are high-power RF amplifier ICs and transistors sometimes mounted in ceramic packages?

Select	Answer
A	Better dissipation of heat
B	Enhanced sensitivity to light
C	High-voltage insulating ability
D	To provide a low-pass frequency response

29. - E6F05

Which describes an optical shaft encoder?

Select	Answer
A	A device which detects rotation of a control by interrupting a light source with a patterned wheel
B	A device for generating RTTY signals by means of a rotating light source
C	A device which measures the strength of a beam of light using analog to digital conversion
D	A digital encryption device often used to encrypt spacecraft control signals

30. - E7A04

How many flip-flops are required to divide a signal frequency by 4?

Select	Answer
A	8
B	1
C	4
D	2

31. - E7B16

What is the effect of intermodulation products in a linear power amplifier?

Select	Answer
A	Creation of parasitic oscillations
B	Transmission of spurious signals
C	Low efficiency
D	All of these choices are correct

32. - E7C11

Which of the following is the common name for a filter network which is equivalent to two L-networks connected back-to-back with the two inductors in series and the capacitors in shunt at the input and output?

Select	Answer
A	Cascode
B	Pi-L
C	Pi
D	Omega

33. - E7D16

When several electrolytic filter capacitors are connected in series to increase the operating voltage of a power supply filter circuit, why should resistors be connected across each capacitor?

Select	Answer
A	To provide a safety bleeder to discharge the capacitors when the supply is off
B	To provide a minimum load current to reduce voltage excursions at light loads
C	To equalize, as much as possible, the voltage drop across each capacitor
D	All of these choices are correct

34. - E7E05

What circuit is added to an FM transmitter to boost the higher audio frequencies?

Select	Answer
A	A pre-emphasis network
B	A heterodyne suppressor
C	A de-emphasis network
D	An audio prescaler

35. - E7F04

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

Select	Answer
A	Combine signals with a quadrature phase relationship
B	Mixing products are converted to voltages and subtracted by adder circuits
C	Emulation of quartz crystal filter characteristics
D	A frequency synthesizer removes the unwanted sidebands

36. - E7G12

What is an integrated circuit operational amplifier?

Select	Answer
A	A RF amplifier used in the UHF and microwave regions
B	A digital audio amplifier whose characteristics are determined by components external to the amplifier
C	A high-gain, direct-coupled differential amplifier with very high input impedance and very low output impedance
D	An amplifier used to increase the average output of frequency modulated amateur signals to the legal limit

37. - E7H10

What information is contained in the lookup table of a direct digital frequency synthesizer?

Select	Answer
A	The phase relationship between a voltage-controlled oscillator and the output waveform
B	The amplitude values that represent a sine-wave output
C	The synthesizer frequency limits and frequency values stored in the radio memories
D	The phase relationship between a reference oscillator and the output waveform

38. - E8A12

What is an advantage of using digital signals instead of analog signals to convey the same information?

Select	Answer
A	Less complex circuitry is required for digital signal generation and detection
B	Digital signals can be regenerated multiple times without error
C	Digital signals always occupy a narrower bandwidth
D	All of these choices are correct

39. - 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	3
B	0.3
C	1000
D	3000

40. - E8C06

What is the necessary bandwidth of a 170-hertz shift, 300-baud ASCII transmission?

Select	Answer
A	0.1 Hz
B	0.5 kHz
C	1.0 kHz
D	0.3 kHz

41. - E8D07

What is a common cause of overmodulation of AFSK signals?

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

42. - E9A02

What antenna has no gain in any direction?

Select	Answer
A	Isotropic antenna
B	Half-wave dipole
C	Yagi
D	Quarter-wave vertical

43. - E9B04

What may occur when a directional antenna is operated at different frequencies within the band for which it was designed?

Select	Answer
A	Element spacing limits could be exceeded
B	Feed point impedance may become negative
C	The E-field and H-field patterns may reverse
D	The gain may change depending on frequency

44. - E9C05

What is an OCFD antenna?

Select	Answer
A	A remotely tunable dipole antenna using orthogonally controlled frequency diversity
B	A dipole feed approximately 1/3 the way from one end with a 4:1 balun to provide multiband operation
C	An eight band dipole antenna using octophase filters
D	A multiband dipole antenna using one-way circular polarization for frequency diversity

45. - E9D07

What is an advantage of using top loading in a shortened HF vertical antenna?

Select	Answer
A	Improved radiation efficiency
B	Lower Q
C	Higher losses
D	Greater structural strength

46. - E9E08

Which of the following measurements is characteristic of a mismatched transmission line?

Select	Answer
A	A reflection coefficient greater than 1
B	A dielectric constant greater than 1
C	An SWR greater than 1:1
D	An SWR less than 1:1

47. - E9F16

Which of the following is a significant difference between foam dielectric coaxial cable and solid dielectric cable, assuming all other parameters are the same?

Select	Answer
A	Foam dielectric has lower safe operating voltage limits
B	Foam dielectric has lower loss per unit of length
C	All of these choices are correct
D	Foam dielectric has higher velocity factor

48. - E9G01

Which of the following can be calculated using a Smith chart?

Select	Answer
A	Antenna radiation pattern
B	Impedance along transmission lines
C	Radio propagation
D	Radiation resistance

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

50. - E0A11

Which of the following injuries can result from using high-power UHF or microwave transmitters?

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