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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?

SelectAnswer
A30 to 300 MHz
B300 to 3000 MHz
C300 kHz to 3 MHz
D3 to 30 MHz

2. - E1A12

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

SelectAnswer
AThey are restricted to phone band segments
BNone; they are allowed on all amateur frequencies
CThey are not permitted above 54 MHz
DThey are restricted to 7.245 MHz, 14.245 MHz, 21.345 MHz, and 28.945 MHz

3. - E1B11

What does PRB-1 require of regulations affecting amateur radio?

SelectAnswer
AUse of wireless devices in a vehicle is exempt from regulation
BNo limitations may be placed on antenna size or placement
CReasonable accommodations of amateur radio must be made
DAmateur radio operations must be permitted in any private residence

4. - E1C13

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

SelectAnswer
AA special endorsement must be requested from the FCC
BOperators must inform the Utilities Technology Council (UTC) of their call sign and coordinates of the station
COperators must inform the FAA of their intent to operate, giving their call sign and distance to the nearest runway
DAn 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?

SelectAnswer
AAll these choices are correct
BA message forwarding station or automatically controlled digital station
CA local repeater or linked repeater station
DA space station, beacon station, or telecommand station

6. - E1E11

What must the VE team do if an examinee scores a passing grade on all examination elements needed for an upgrade or new license?

SelectAnswer
AIssue the examinee the new or upgrade license
BAll these choices are correct
CPhotocopy all examination documents and forward them to the FCC for processing
DThree VEs must certify that the examinee is qualified for the license grant and that they have complied with the administering VE requirements

7. - E1F08

Which of the following types of amateur station communications are prohibited?

SelectAnswer
ACommunications that have political content, except as allowed by the Fairness Doctrine
BCommunications transmitted for hire or material compensation, except as otherwise provided in the rules
CCommunications that have religious content
DCommunications in a language other than English

8. - E2A06

What are Keplerian elements?

SelectAnswer
AEncrypting codes used for spread spectrum modulation
BParameters that define the orbit of a satellite
CHigh-emission heater filaments used in magnetron tubes
DPhase reversing elements in a Yagi antenna

9. - E2B04

How is color information sent in analog SSTV?

SelectAnswer
AColor information is sent on a 2.8 kHz subcarrier
BColor is sent in a color burst at the end of each line
CColor lines are sent sequentially
DColor is amplitude modulated on the frequency modulated intensity signal

10. - E2C04

Which of the following frequencies are sometimes used for amateur radio mesh networks?

SelectAnswer
AFrequencies shared with various unlicensed wireless data services
BCable TV channels 41 through 43
CHF frequencies where digital communications are permitted
DThe 60 meter band channel centered on 5373 kHz

11. - E2D09

What type of modulation is used for JT65 contacts?

SelectAnswer
AIEEE 802.11
BRTTY
CMulti-tone AFSK
DPSK

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?

SelectAnswer
AThe protocol version you are using is not supported by the digital station
BAnother station you are unable to hear is using the frequency
CYour transmit frequency is incorrect
DAll these choices are correct

13. - E3A13

Which of these emission modes is best for auroral propagation?

SelectAnswer
ARTTY
BFM
CSSB
DCW

14. - E3B02

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

SelectAnswer
A7500 miles
B1000 miles
C2500 miles
D5000 miles

15. - E3C12

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

SelectAnswer
AIt stays the same
BIt peaks at roughly 14 MHz
CIt decreases
DIt increases

16. - E4A11

How should an antenna analyzer be connected when measuring antenna resonance and feed point impedance?

SelectAnswer
AConnect the antenna feed line directly to the analyzer's connector
BLoosely couple the analyzer near the antenna base
CLoosely couple the antenna and a dummy load to the analyzer
DConnect the analyzer via a high-impedance transformer to the antenna

17. - E4B05

What three test loads are used to calibrate an RF vector network analyzer?

SelectAnswer
AShort circuit, open circuit, and 50 ohms
B50 ohms through 1/8 wavelength, 1/4 wavelength, and 1/2 wavelength of coaxial cable
C50 ohms, 75 ohms, and 90 ohms
DShort circuit, open circuit, and resonant circuit

18. - E4C11

Why can an attenuator be used to reduce receiver overload on the lower frequency HF bands with little or no impact on signal-to-noise ratio?

SelectAnswer
AAtmospheric noise is generally greater than internally generated noise even after attenuation
BSignals are attenuated separately from the noise
CThe attenuator has a low-pass filter to increase the strength of lower frequency signals
DThe attenuator has a noise filter to suppress interference

19. - E4D10

What does a third-order intercept level of 40 dBm mean with respect to receiver performance?

SelectAnswer
AA pair of 40 dBm input signals will theoretically generate a third-order intermodulation product that has the same output amplitude as either of the input signals
BSignals less than 40 dBm will not generate audible third-order intermodulation products
CA pair of 1 mW input signals will produce a third-order intermodulation product that is 40 dB stronger than the input signal
DThe receiver can tolerate signals up to 40 dB above the noise floor without producing third-order intermodulation products

20. - E4E05

How can radio frequency interference from an AC motor be suppressed?

SelectAnswer
ABy installing a bypass capacitor in series with the motor leads
BBy using a ground-fault current interrupter in the circuit used to power the motor
CBy installing a brute-force AC-line filter in series with the motor leads
DBy installing a high-pass filter in series with the motor's power leads

21. - E5A16

What is the resonant frequency of an RLC circuit if R is 33 ohms, L is 50 microhenries and C is 10 picofarads?

SelectAnswer
A7.12 MHz
B23.5 kHz
C7.12 kHz
D23.5 MHz

22. - E5B01

What is the term for the time required for the capacitor in an RC circuit to be charged to 63.2% of the applied voltage or to discharge to 36.8% of its initial voltage?

SelectAnswer
AA time factor of one
BOne exponential period
COne time constant
DAn exponential rate of one

23. - E5C11

Which point in Figure E5-1 best represents the impedance of a series circuit consisting of a 300-ohm resistor and an 18-microhenry inductor at 3.505 MHz?

SelectAnswer
APoint 3
BPoint 1
CPoint 7
DPoint 8

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?

SelectAnswer
A141.4 watts
B70.7 watts
C100 watts
D200 watts

25. - E6A04

What is the name given to an impurity atom that adds holes to a semiconductor crystal structure?

SelectAnswer
AAcceptor impurity
BInsulator impurity
CN-type impurity
DDonor impurity

26. - E6B07

What is the failure mechanism when a junction diode fails due to excessive current?

SelectAnswer
ACharge carrier depletion
BExcessive inverse voltage
CExcessive junction temperature
DInsufficient forward voltage

27. - E6C04

Which of the following is an advantage of BiCMOS logic?

SelectAnswer
AIt has the high input impedance of CMOS and the low output impedance of bipolar transistors
BIts simplicity results in much less expensive devices than standard CMOS
CIt is immune to electrostatic damage
DAll these choices are correct

28. - E6D04

Which materials are commonly used as a core in an inductor?

SelectAnswer
APolystyrene and polyethylene
BCobalt and aluminum
CFerrite and brass
DTeflon and Delrin

29. - E6E01

Why is gallium arsenide (GaAs) useful for semiconductor devices operating at UHF and higher frequencies?

SelectAnswer
ALower transconductance
BHigher noise figures
CLower junction voltage drop
DHigher electron mobility

30. - E6F05

Which describes an optical shaft encoder?

SelectAnswer
AA device that detects rotation of a control by interrupting a light source with a patterned wheel
BA device that measures the strength of a beam of light using analog to digital conversion
CA digital encryption device often used to encrypt spacecraft control signals
DA device for generating RTTY signals by means of a rotating light source

31. - E7A10

What is a truth table?

SelectAnswer
AA table of logic symbols that indicate the logic states of an op-amp
BA diagram showing logic states when the digital device output is true
CA table of logic symbols that indicate the high logic states of an op-amp
DA list of inputs and corresponding outputs for a digital device

32. - E7B04

Where on the load line of a Class A common emitter amplifier would bias normally be set?

SelectAnswer
AWhere the load line intersects the voltage axis
BAt a point where the load line intersects the zero bias current curve
CApproximately halfway between saturation and cutoff
DAt a point where the bias resistor equals the load resistor

33. - E7C02

Which of the following is a property of a T-network with series capacitors and a parallel shunt inductor?

SelectAnswer
AIt is a band-pass filter
BIt is a notch filter
CIt is a high-pass filter
DIt is a low-pass filter

34. - E7D05

Which of the following types of linear voltage regulator places a constant load on the unregulated voltage source?

SelectAnswer
AA series regulator
BA constant current source
CA shunt current source
DA shunt regulator

35. - E7E06

Why is de-emphasis commonly used in FM communications receivers?

SelectAnswer
ATo reduce impulse noise reception
BFor higher efficiency
CTo remove third-order distortion products
DFor compatibility with transmitters using phase modulation

36. - E7F01

What is meant by direct digital conversion as applied to software defined radios?

SelectAnswer
AIncoming RF is digitized by an analog-to-digital converter without being mixed with a local oscillator signal
BSoftware is converted from source code to object code during operation of the receiver
CA switching mixer is used to generate I and Q signals directly from the RF input
DIncoming RF is converted to a control voltage for a voltage controlled oscillator

37. - E7G12

What is an operational amplifier?

SelectAnswer
AAn amplifier used to increase the average output of frequency modulated amateur signals to the legal limit
BA high-gain, direct-coupled differential amplifier with very high input impedance and very low output impedance
CA RF amplifier used in the UHF and microwave regions
DA digital audio amplifier whose characteristics are determined by components external to the amplifier

38. - E7H02

What is a microphonic?

SelectAnswer
AAn IC used for amplifying microphone signals
BExcess loading of the microphone by an oscillator
CChanges in oscillator frequency due to mechanical vibration
DDistortion caused by RF pickup on the microphone cable

39. - E8A05

What of the following instruments would be the most accurate for measuring the RMS voltage of a complex waveform?

SelectAnswer
AA true-RMS calculating meter
BA D'Arsonval meter
CAn absorption wave meter
DA grid dip meter

40. - E8B08

What describes Orthogonal Frequency Division Multiplexing?

SelectAnswer
AA frequency modulation technique that uses non-harmonically related frequencies
BA digital modulation technique using subcarriers at frequencies chosen to avoid intersymbol interference
CA bandwidth compression technique using Fourier transforms
DA digital mode for narrow-band, slow-speed transmissions

41. - E8C01

How is Forward Error Correction implemented?

SelectAnswer
ABy transmitting extra data that may be used to detect and correct transmission errors
BBy the receiving station repeating each block of three data characters
CBy transmitting a special algorithm to the receiving station along with the data characters
DBy varying the frequency shift of the transmitted signal according to a predefined algorithm

42. - E8D06

What is the advantage of including parity bits in ASCII characters?

SelectAnswer
ASome types of errors can be detected
BForeign language characters can be sent
CThe signal can overpower interfering signals
DFaster transmission rate

43. - E9A02

What is the effective radiated power relative to a dipole of a repeater station with 150 watts transmitter power output, 2 dB feed line loss, 2.2 dB duplexer loss, and 7 dBd antenna gain?

SelectAnswer
A286 watts
B1977 watts
C78.7 watts
D420 watts

44. - E9B09

What type of computer program technique is commonly used for modeling antennas?

SelectAnswer
AGraphical analysis
BMethod of Moments
CMutual impedance analysis
DCalculus differentiation with respect to physical properties

45. - E9C06

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

SelectAnswer
AIt changes the radiation pattern from horizontal to vertical polarization
BIt decreases the ground loss
CIt changes the radiation pattern from bidirectional to unidirectional
DIt reflects the standing waves on the antenna elements back to the transmitter

46. - E9D01

How much does the gain of an ideal parabolic dish antenna change when the operating frequency is doubled?

SelectAnswer
A6 dB
B4 dB
C3 dB
D2 dB

47. - E9E01

What system matches a higher-impedance transmission line to a lower-impedance antenna by connecting the line to the driven element in two places spaced a fraction of a wavelength each side of element center?

SelectAnswer
AThe stub matching system
BThe gamma matching system
CThe delta matching system
DThe omega matching system

48. - E9F11

What impedance does a 1/8-wavelength transmission line present to a generator when the line is open at the far end?

SelectAnswer
AA capacitive reactance
BInfinite
CAn inductive reactance
DThe same as the characteristic impedance of the line

49. - E9G07

On the Smith chart shown in Figure E9-3, what is the only straight line shown?

SelectAnswer
AThe reactance axis
BThe current axis
CThe resistance axis
DThe voltage axis

50. - E9H07

Why is RF attenuation used when direction-finding?

SelectAnswer
ATo compensate for isotropic directivity and the antenna effect of feed lines
BTo prevent receiver overload which reduces pattern nulls
CTo increase receiver sensitivity
DTo narrow the receiver bandwidth