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

2. - E1A14

Except in some parts of Alaska, what is the maximum power permitted on the 630 meter band?

Select	Answer
A	1 watt EIRP
B	5 watts EIRP
C	50 watts PEP
D	100 watts PEP

3. - E1B09

Which amateur stations may be operated under RACES rules?

Select	Answer
A	Only those club stations licensed to Amateur Extra Class operators
B	Any FCC-licensed amateur station certified by the responsible civil defense organization for the area served
C	Any FCC-licensed amateur station participating in the Military Auxiliary Radio System (MARS)
D	Any FCC-licensed amateur station except a Technician Class

4. - E1C13

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

Select	Answer
A	Operators must inform the FAA of their intent to operate, giving their call sign and distance to the nearest runway
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	An environmental impact statement must be filed with the Department of the Interior

5. - E1D12

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

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

6. - E1E04

Which of the following best describes the Volunteer Examiner accreditation process?

Select	Answer
A	Each General, Advanced and Amateur Extra Class operator is automatically accredited as a VE when the license is granted
B	The amateur operator applying must pass a VE examination administered by the FCC Enforcement Bureau
C	The prospective VE obtains accreditation from the FCC
D	The procedure by which a VEC confirms that the VE applicant meets FCC requirements to serve as an examiner

7. - E1F07

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

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

8. - E2A08

Why should effective radiated power to a satellite that uses a linear transponder be limited?

Select	Answer
A	To prevent the satellite from emitting out-of-band signals
B	To prevent creating errors in the satellite telemetry
C	To avoid interfering with terrestrial QSOs
D	To avoid reducing the downlink power to all other users

9. - E2B02

How many horizontal lines make up a fast-scan (NTSC) television frame?

Select	Answer
A	1080
B	525
C	60
D	30

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	Repeater contacts between U.S. club members
C	Special event contacts between stations in the U.S.
D	Contacts using tactical call signs

11. - E2D10

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

Select	Answer
A	APRS stations with General Personnel Scanners can automatically relay the participant numbers and time as they pass the check points
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	All these choices are correct
D	An APRS station with an emergency medical technician can automatically transmit medical data to the nearest hospital

12. - E2E10

Which of these digital modes has the narrowest bandwidth?

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

13. - E3A14

What is meant by circularly polarized electromagnetic waves?

Select	Answer
A	Waves that circle the Earth
B	Waves with a rotating electric field
C	Waves produced by a loop antenna
D	Waves with an electric field bent into a circular shape

14. - E3B02

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

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

15. - E3C12

How does the maximum range of ground-wave propagation change when the signal frequency is increased?

Select	Answer
A	It decreases
B	It peaks at roughly 14 MHz
C	It stays the same
D	It increases

16. - E4A03

Which of the following test instruments is used to display spurious signals and/or intermodulation distortion products generated by an SSB transmitter?

Select	Answer
A	A time-domain reflectometer
B	A wattmeter
C	A logic analyzer
D	A spectrum analyzer

17. - E4B11

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

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

18. - E4C02

Which of the following receiver circuits can be effective in eliminating interference from strong out-of-band signals?

Select	Answer
A	A notch filter
B	A front-end filter or pre-selector
C	A properly adjusted product detector
D	A narrow IF filter

19. - E4D11

Why are odd-order intermodulation products, created within a receiver, of particular interest compared to other products?

Select	Answer
A	Odd-order intermodulation produces three products for every input signal within the band of interest
B	Odd-order products overload the IF filters
C	Odd-order products are an indication of poor image rejection
D	Odd-order products of two signals in the band of interest are also likely to be within the band

20. - E4E07

Which of the following can cause shielded cables to radiate or receive interference?

Select	Answer
A	Use of braided shielding material
B	Common-mode currents on the shield and conductors
C	Low inductance ground connections at both ends of the shield
D	Tying all ground connections to a common point resulting in differential-mode currents in the shield

21. - E5A04

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

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

22. - E5B07

What is the phase angle between the voltage across and the current through a series RLC circuit if XC is 500 ohms, R is 1 kilohm, and XL is 250 ohms?

Select	Answer
A	14.0 degrees with the voltage lagging the current
B	68.2 degrees with the voltage lagging the current
C	14.0 degrees with the voltage leading the current
D	68.2 degrees with the voltage leading the current

23. - E5C03

Which of the following represents an inductive reactance in polar coordinates?

Select	Answer
A	A positive magnitude
B	A negative phase angle
C	A positive phase angle
D	A negative magnitude

24. - E5D04

Why are short connections used at microwave frequencies?

Select	Answer
A	To reduce noise figure
B	To increase neutralizing resistance
C	To reduce phase shift along the connection
D	To increase compensating capacitance

25. - E6A02

Which of the following semiconductor materials contains excess free electrons?

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

26. - E6B01

What is the most useful characteristic of a Zener diode?

Select	Answer
A	A constant current drop under conditions of varying voltage
B	A negative resistance region
C	A constant voltage drop under conditions of varying current
D	An internal capacitance that varies with the applied voltage

27. - E6C04

Which of the following is an advantage of BiCMOS logic?

Select	Answer
A	Its simplicity results in much less expensive devices than standard CMOS
B	All these choices are correct
C	It has the high input impedance of CMOS and the low output impedance of bipolar transistors
D	It is immune to electrostatic damage

28. - E6D10

What is a primary advantage of using a toroidal core instead of a solenoidal core in an inductor?

Select	Answer
A	Toroidal cores confine most of the magnetic field within the core material
B	Toroidal cores make it easier to couple the magnetic energy into other components
C	Toroidal cores exhibit greater hysteresis
D	Toroidal cores have lower Q characteristics

29. - E6E10

What advantage does surface-mount technology offer at RF compared to using through-hole components?

Select	Answer
A	Shorter circuit-board traces
B	Components have less parasitic inductance and capacitance
C	Smaller circuit area
D	All these choices are correct

30. - E6F03

What is the most common configuration of an optoisolator or optocoupler?

Select	Answer
A	An amplitude modulated helium-neon laser
B	An LED and a phototransistor
C	A frequency modulated helium-neon laser
D	A lens and a photomultiplier

31. - E7A05

Which of the following is a circuit that continuously alternates between two states without an external clock?

Select	Answer
A	Astable multivibrator
B	J-K flip-flop
C	Monostable multivibrator
D	T flip-flop

32. - E7B02

What is a Class D amplifier?

Select	Answer
A	A low power amplifier that uses a differential amplifier for improved linearity
B	An amplifier that uses drift-mode FETs for high efficiency
C	A type of amplifier that uses switching technology to achieve high efficiency
D	A frequency doubling amplifier

33. - E7C09

What is a crystal lattice filter?

Select	Answer
A	A filter with narrow bandwidth and steep skirts made using quartz crystals
B	An audio filter made with four quartz crystals that resonate at 1 kHz intervals
C	A power supply filter made with interlaced quartz crystals
D	A filter using lattice-shaped quartz crystals for high-Q performance

34. - E7D14

What is the purpose of connecting equal-value resistors across power supply filter capacitors connected in series?

Select	Answer
A	Provide a minimum load on the supply
B	Equalize the voltage across each capacitor
C	Discharge the capacitors when voltage is removed
D	All these choices are correct

35. - E7E11

Which type of detector circuit is used for demodulating SSB signals?

Select	Answer
A	Product detector
B	Phase detector
C	Phase comparator
D	Discriminator

36. - E7F13

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

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

37. - E7G02

What is ringing in a filter?

Select	Answer
A	Undesired oscillations added to the desired signal
B	An echo caused by a long time delay
C	Partial cancellation of the signal over a range of frequencies
D	A reduction in high frequency response

38. - E7H14

What is a phase-locked loop circuit?

Select	Answer
A	An electronic circuit also known as a monostable multivibrator
B	An electronic servo loop consisting of a ratio detector, reactance modulator, and voltage-controlled oscillator
C	An electronic servo loop consisting of a phase detector, a low-pass filter, a voltage-controlled oscillator, and a stable reference oscillator
D	An electronic circuit consisting of a precision push-pull amplifier with a differential input

39. - E8A11

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

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

40. - E8B06

What is the deviation ratio of an FM-phone signal having a maximum frequency swing of plus or minus 7.5 kHz when the maximum modulation frequency is 3.5 kHz?

Select	Answer
A	47
B	0.47
C	0.214
D	2.14

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

42. - E8D01

Why are received spread spectrum signals resistant to interference?

Select	Answer
A	The receiver is always equipped with a digital blanker
B	If interference is detected by the receiver it will signal the transmitter to change frequencies
C	Signals not using the spread spectrum algorithm are suppressed in the receiver
D	The high power used by a spread spectrum transmitter keeps its signal from being easily overpowered

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	252 watts
C	63.2 watts
D	632 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 uniform value of current
B	A wire is modeled as a single sine-wave voltage source
C	A wire is modeled as a series of segments, each having a distinct value of voltage across it
D	A wire is modeled as a single sine-wave current generator

45. - E9C05

Which of the following is a type of OCFD antenna?

Select	Answer
A	A remotely tunable dipole antenna using orthogonally controlled frequency diversity
B	A multiband dipole antenna using one-way circular polarization for frequency diversity
C	A folded dipole center-fed with 300-ohm transmission line
D	A dipole fed approximately 1/3 the way from one end with a 4:1 balun to provide multiband operation

46. - E9D03

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

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

47. - E9E10

Which of these choices is an effective way to match an antenna with a 100-ohm feed point impedance to a 50-ohm coaxial cable feed line?

Select	Answer
A	Insert a 1/2 wavelength piece of 300-ohm twinlead in series between the antenna terminals and the 50-ohm feed cable
B	Insert a 1/4-wavelength piece of 75-ohm coaxial cable transmission line in series between the antenna terminals and the 50-ohm feed cable
C	Connect a 1/4-wavelength open stub of 300-ohm twinlead in parallel with the coaxial feed line where it connects to the antenna
D	Connect a 1/2 wavelength shorted stub of 75-ohm cable in parallel with the 50-ohm cable where it attaches to the antenna

48. - E9F05

What is the approximate physical length of a solid polyethylene dielectric coaxial transmission line that is electrically 1/4 wavelength long at 14.1 MHz?

Select	Answer
A	5.3 meters
B	3.5 meters
C	10.6 meters
D	4.3 meters

49. - E9G09

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

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

50. - E9H07

Why is RF attenuation used when direction-finding?

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