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

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1. - E0A03

Over what range of frequencies are the FCC human body RF exposure limits most restrictive?

Select	Answer
A	3 to 30 MHz
B	300 kHz to 3 MHz
C	300 to 3000 MHz
D	30 to 300 MHz

2. - E1A14

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

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

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. - E1C01

What is the maximum bandwidth for a data emission on 60 meters?

Select	Answer
A	60 Hz
B	1.5 kHz
C	170 Hz
D	2.8 kHz

5. - E1D02

Which of the following may transmit special codes intended to obscure the meaning of messages?

Select	Answer
A	Auxiliary relay links carrying repeater audio
B	Binary control characters
C	Telecommand signals from a space telecommand station
D	Data containing personal information

6. - E1E09

What may be the penalty for a VE who fraudulently administers or certifies an examination?

Select	Answer
A	Revocation of the VE's amateur station license grant and the suspension of the VE's amateur operator license grant
B	A fine of up to $1000 per occurrence
C	All these choices are correct
D	A sentence of up to one year in prison

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

8. - E2A06

What are Keplerian elements?

Select	Answer
A	Encrypting codes used for spread spectrum modulation
B	High-emission heater filaments used in magnetron tubes
C	Phase reversing elements in a Yagi antenna
D	Parameters that define the orbit of a satellite

9. - E2B09

What hardware, other than a receiver with SSB capability and a suitable computer, is needed to decode SSTV using Digital Radio Mondiale (DRM)?

Select	Answer
A	No other hardware is needed
B	A special notch filter to remove synchronization pulses
C	A special front end limiter
D	A special IF converter

10. - E2C11

How should you generally identify your station when attempting to contact a DX station during a contest or in a pileup?

Select	Answer
A	Send only the last two letters of your call sign until you make contact
B	Send your full call sign and grid square
C	Send the call sign of the DX station three times, the words this is,then your call sign three times
D	Send your full call sign once or twice

11. - E2D10

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

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

12. - E2E07

Which of the following is a possible reason that attempts to initiate contact with a digital station on a clear frequency are unsuccessful?

Select	Answer
A	Your transmit frequency is incorrect
B	All these choices are correct
C	The protocol version you are using is not supported by the digital station
D	Another station you are unable to hear is using the frequency

13. - E3A08

When a meteor strikes the Earth's atmosphere, a cylindrical region of free electrons is formed at what layer of the ionosphere?

Select	Answer
A	The F1 layer
B	The D layer
C	The F2 layer
D	The E layer

14. - E3B02

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

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

15. - E3C11

What does VOACAP software model?

Select	Answer
A	AC current and impedance
B	HF propagation
C	AC voltage and impedance
D	VHF radio propagation

16. - E4A08

Which of the following measures SWR?

Select	Answer
A	An antenna analyzer
B	A spectrum analyzer
C	An ohmmeter
D	A Q meter

17. - E4B01

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

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

18. - E4C09

Which of the following choices is a good reason for selecting a high frequency for the design of the IF in a superheterodyne HF or VHF communications receiver?

Select	Answer
A	Reduced drift
B	Improved receiver noise figure
C	Easier for front-end circuitry to eliminate image responses
D	Fewer components in the receiver

19. - E4D11

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

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

20. - E4E04

How can conducted and radiated noise caused by an automobile alternator be suppressed?

Select	Answer
A	By installing a noise suppression resistor and a blocking capacitor in both leads
B	By installing filter capacitors in series with the DC power lead and a blocking capacitor in the field lead
C	By installing a high-pass filter in series with the radio's power lead and a low-pass filter in parallel with the field lead
D	By connecting the radio's power leads directly to the battery and by installing coaxial capacitors in line with the alternator leads

21. - 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	High, as compared to the circuit resistance
D	Approximately equal to circuit resistance

22. - E5B09

What is the relationship between the AC current through a capacitor and the voltage across a capacitor?

Select	Answer
A	Current leads voltage by 90 degrees
B	Voltage and current are 180 degrees out of phase
C	Voltage and current are in phase
D	Voltage leads current by 90 degrees

23. - E5C09

When using rectangular coordinates to graph the impedance of a circuit, what do the axes represent?

Select	Answer
A	The X axis represents the phase angle and the Y axis represents the magnitude
B	The X axis represents the magnitude and the Y axis represents the phase angle
C	The X axis represents the resistive component and the Y axis represents the reactive component
D	The X axis represents the reactive component and the Y axis represents the resistive component

24. - E5D13

How many watts are consumed in a circuit consisting of a 100-ohm resistor in series with a 100-ohm inductive reactance drawing 1 ampere?

Select	Answer
A	200 watts
B	141.4 watts
C	100 watts
D	70.7 watts

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. - E6B11

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

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

27. - E6C06

Why do CMOS digital integrated circuits have high immunity to noise on the input signal or power supply?

Select	Answer
A	The input switching threshold is about one-half the power supply voltage
B	The input switching threshold is about two times the power supply voltage
C	Bandwidth is very limited
D	Large bypass capacitance is inherent

28. - E6D08

What is one reason for using powdered-iron cores rather than ferrite cores in an inductor?

Select	Answer
A	Powdered-iron cores generally have greater initial permeability
B	Powdered-iron cores generally maintain their characteristics at higher currents
C	Powdered-iron cores generally require fewer turns to produce a given inductance
D	Powdered-iron cores use smaller diameter wire for the same inductance

29. - E6E04

Which is the most common input and output impedance of circuits that use MMICs?

Select	Answer
A	300 ohms
B	10 ohms
C	450 ohms
D	50 ohms

30. - E6F02

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

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

31. - E7A01

Which circuit is bistable?

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

32. - E7B17

Why are odd-order rather than even-order intermodulation distortion products of concern in linear power amplifiers?

Select	Answer
A	Because they invert the sidebands causing distortion
B	Because they are relatively close in frequency to the desired signal
C	Because they are relatively far in frequency from the desired signal
D	Because they maintain the sidebands, thus causing multiple duplicate signals

33. - E7C10

Which of the following filters would be the best choice for use in a 2 meter band repeater duplexer?

Select	Answer
A	A crystal filter
B	An L-C filter
C	A DSP filter
D	A cavity filter

34. - E7D11

What is the function of the pass transistor in a linear voltage regulator circuit?

Select	Answer
A	Maintains nearly constant output impedance over a wide range of load current
B	Maintains nearly constant output voltage over a wide range of load current
C	Provides a stable input impedance over a wide range of source voltage
D	Permits a wide range of output voltage settings

35. - E7E02

What is the function of a reactance modulator?

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

36. - E7F11

What sets the minimum detectable signal level for a direct-sampling SDR receiver in the absence of atmospheric or thermal noise?

Select	Answer
A	Missing codes and jitter
B	Data storage transfer rate
C	Reference voltage level and sample width in bits
D	Sample clock phase noise

37. - E7G01

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

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

38. - E7H15

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

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

39. - E8A04

What is "dither" with respect to analog-to-digital converters?

Select	Answer
A	A method of decimation by randomly skipping samples
B	An abnormal condition where the converter cannot settle on a value to represent the signal
C	A small amount of noise added to the input signal to allow more precise representation of a signal over time
D	An error caused by irregular quantization step size

40. - E8B05

What is the deviation ratio of an FM-phone signal having a maximum frequency swing of plus-or-minus 5 kHz when the maximum modulation frequency is 3 kHz?

Select	Answer
A	0.6
B	0.167
C	60
D	1.67

41. - E8C12

What factors affect the bandwidth of a transmitted CW signal?

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

42. - E8D08

What parameter evaluates distortion of an AFSK signal caused by excessive input audio levels?

Select	Answer
A	Intermodulation Distortion (IMD)
B	Signal-to-noise ratio
C	Repeat Request Rate (RRR)
D	Baud rate

43. - E9A09

What is antenna efficiency?

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

44. - E9B01

In the antenna radiation pattern shown in Figure E9-1, what is the beamwidth?

Select	Answer
A	50 degrees
B	25 degrees
C	75 degrees
D	30 degrees

45. - E9C02

What is the radiation pattern of two 1/4-wavelength vertical antennas spaced 1/4 wavelength apart and fed 90 degrees out of phase?

Select	Answer
A	Cardioid
B	A figure-8 broadside to the axis of the array
C	Omni-directional
D	A figure-8 end-fire along the axis of the array

46. - E9D12

Which of the following would provide the best RF ground for your station?

Select	Answer
A	An electrically short connection to a metal water pipe
B	An electrically short connection to 3 or 4 interconnected ground rods driven into the Earth
C	An electrically short connection to 3 or 4 interconnected ground rods via a series RF choke
D	A 50-ohm resistor connected to ground

47. - E9E09

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

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

48. - E9F03

Why is the physical length of a coaxial cable transmission line shorter than its electrical length?

Select	Answer
A	The surge impedance is higher in a parallel feed line
B	Skin effect is less pronounced in the coaxial cable
C	The characteristic impedance is higher in a parallel feed line
D	Electrical signals move more slowly in a coaxial cable than in air

49. - E9G11

How are the wavelength scales on a Smith chart calibrated?

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

50. - E9H01

When constructing a Beverage antenna, which of the following factors should be included in the design to achieve good performance at the desired frequency?

Select	Answer
A	It should be configured as a four-sided loop
B	It should be one or more wavelengths long
C	Its overall length must not exceed 1/4 wavelength
D	It must be mounted more than 1 wavelength above ground

Figure E9-1