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

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1. - E0A07

How may dangerous levels of carbon monoxide from an emergency generator be detected?

Select	Answer
A	By the odor
B	Only with a carbon monoxide detector
C	By the yellowish appearance of the gas
D	Any ordinary smoke detector can be used

2. - E1A04

With your transceiver displaying the carrier frequency of phone signals, you hear a DX station calling CQ on 3.601 MHz LSB. Is it legal to return the call using lower sideband on the same frequency?

Select	Answer
A	No, U.S. stations are not permitted to use phone emissions below 3.610 MHz
B	Yes, because the displayed frequency is within the 75 meter phone band segment
C	Yes, because the DX station initiated the contact
D	No, the sideband will extend beyond the edge of the phone band segment

3. - E1B08

What limitations may the FCC place on an amateur station if its signal causes interference to domestic broadcast reception, assuming that the receivers involved are of good engineering design?

Select	Answer
A	The amateur station must avoid transmitting during certain hours on frequencies that cause the interference
B	The amateur station must cease operation
C	The amateur station must cease operation on all frequencies below 30 MHz
D	The amateur station must cease operation on all frequencies above 30 MHz

4. - E1C11

Which of the following operating arrangements allows an FCC-licensed U.S. citizen to operate in many European countries, and alien amateurs from many European countries to operate in the U.S.?

Select	Answer
A	ITU reciprocal license
B	All these choices are correct
C	IARP agreement
D	CEPT agreement

5. - E1D09

Which UHF amateur bands have frequencies authorized for space stations?

Select	Answer
A	70 cm and 33 cm
B	70 cm and 13 cm
C	70 cm only
D	33 cm and 13 cm

6. - E1E09

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

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

7. - E1F01

On what frequencies are spread spectrum transmissions permitted?

Select	Answer
A	Only on amateur frequencies above 222 MHz
B	Only on amateur frequencies above 420 MHz
C	Only on amateur frequencies above 144 MHz
D	Only on amateur frequencies above 50 MHz

8. - E2A02

Which of the following occurs when a satellite is using an inverting linear transponder?

Select	Answer
A	Upper sideband on the uplink becomes lower sideband on the downlink, and vice versa
B	All these choices are correct
C	Doppler shift is reduced because the uplink and downlink shifts are in opposite directions
D	Signal position in the band is reversed

9. - E2B01

How many times per second is a new frame transmitted in a fast-scan (NTSC) television system?

Select	Answer
A	60
B	90
C	120
D	30

10. - E2C01

What indicator is required to be used by U.S.-licensed operators when operating a station via remote control and the remote transmitter is located in the U.S.?

Select	Answer
A	/ followed by the ARRL Section of the remote station
B	/ followed by the USPS two-letter abbreviation for the state in which the remote station is located
C	/R# where # is the district of the remote station
D	No additional indicator is required

11. - E2D02

Which of the following is a good technique for making meteor scatter contacts?

Select	Answer
A	All these choices are correct
B	15-second timed transmission sequences with stations alternating based on location
C	Use of special digital modes
D	Short transmissions with rapidly repeated call signs and signal reports

12. - E2E08

Which of the following HF digital modes can be used to transfer binary files?

Select	Answer
A	Hellschreiber
B	AMTOR
C	PACTOR
D	RTTY

13. - E3A06

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	Switch to a higher frequency HF band
D	Wait 24 hours before attempting another communication on the band

14. - E3B05

Which amateur bands typically support long-path propagation?

Select	Answer
A	160 meters to 10 meters
B	Only 30 meters to 10 meters
C	6 meters to 2 meters
D	Only 160 meters to 40 meters

15. - E3C11

What does VOACAP software model?

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

16. - E4A09

Which of the following is good practice when using an oscilloscope probe?

Select	Answer
A	All these choices are correct
B	Never use a DC-coupled probe to measure an AC circuit
C	Keep the signal ground connection of the probe as short as possible
D	Never use a high-impedance probe to measure a low-impedance circuit

17. - E4B01

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

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

18. - E4C06

A CW receiver with the AGC off has an equivalent input noise power density of -174 dBm/Hz. What would be the level of an unmodulated carrier input to this receiver that would yield an audio output SNR of 0 dB in a 400 Hz noise bandwidth?

Select	Answer
A	-164 dBm
B	-155 dBm
C	-174 dBm
D	-148 dBm

19. - E4D05

What transmitter frequencies would cause an intermodulation-product signal in a receiver tuned to 146.70 MHz when a nearby station transmits on 146.52 MHz?

Select	Answer
A	173.35 MHz and 139.40 MHz
B	146.88 MHz and 146.34 MHz
C	146.10 MHz and 147.30 MHz
D	146.34 MHz and 146.61 MHz

20. - E4E03

Which of the following signals might a receiver noise blanker be able to remove from desired signals?

Select	Answer
A	Signals that have a sharply peaked frequency distribution
B	Signals that are constant at all IF levels
C	Signals that appear across a wide bandwidth
D	Signals that appear at one IF but not another

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?

Select	Answer
A	7.12 kHz
B	23.5 kHz
C	23.5 MHz
D	7.12 MHz

22. - E5B09

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

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

23. - E5C06

What does the impedance 50-j25 represent?

Select	Answer
A	25 ohms resistance in series with 50 ohms inductive reactance
B	25 ohms resistance in series with 50 ohms capacitive reactance
C	50 ohms resistance in series with 25 ohms capacitive reactance
D	50 ohms resistance in series with 25 ohms inductive reactance

24. - E5D12

How many watts are consumed in a circuit having a power factor of 0.2 if the input is 100 VAC at 4 amperes?

Select	Answer
A	2000 watts
B	50 watts
C	400 watts
D	80 watts

25. - E6A09

What is a depletion-mode FET?

Select	Answer
A	Any FET without a channel
B	Any FET for which holes are the majority carriers
C	An FET that has no current flow between source and drain when no gate voltage is applied
D	An FET that exhibits a current flow between source and drain when no gate voltage is applied

26. - E6B03

What type of bias is required for an LED to emit light?

Select	Answer
A	Forward bias
B	Zero bias
C	Reverse bias
D	Inductive bias

27. - E6C01

What is the function of hysteresis in a comparator?

Select	Answer
A	To prevent input noise from causing unstable output signals
B	To increase the sensitivity
C	To cause the output to change states continually
D	To allow the comparator to be used with AC input signals

28. - E6D01

Why should core saturation of an impedance matching transformer be avoided?

Select	Answer
A	Magnetic flux would increase with frequency
B	Temporary changes of the core permeability could result
C	RF susceptance would increase
D	Harmonics and distortion could result

29. - E6E08

How is power supplied to the most common type of MMIC?

Select	Answer
A	Through a capacitor and RF choke connected to the amplifier input lead
B	MMICs require no operating bias
C	Directly to the bias voltage (VCC IN) lead
D	Through a resistor and/or RF choke connected to the amplifier output lead

30. - E6F09

What is the efficiency of a photovoltaic cell?

Select	Answer
A	Cost per kilowatt-hour generated
B	The open-circuit voltage divided by the short-circuit current under full illumination
C	The output RF power divided by the input DC power
D	The relative fraction of light that is converted to current

31. - E7A03

Which of the following can divide the frequency of a pulse train by 2?

Select	Answer
A	An OR gate
B	An XOR gate
C	A multiplexer
D	A flip-flop

32. - E7B06

Which of the following amplifier types reduces even-order harmonics?

Select	Answer
A	Push-push
B	Class AB
C	Class C
D	Push-pull

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

34. - E7D05

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

Select	Answer
A	A series regulator
B	A shunt current source
C	A shunt regulator
D	A constant current source

35. - E7E09

What occurs when an excessive amount of signal energy reaches a mixer circuit?

Select	Answer
A	Mixer blanking occurs
B	A beat frequency is generated
C	Automatic limiting occurs
D	Spurious mixer products are generated

36. - E7F13

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

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

37. - E7G02

What is ringing in a filter?

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

38. - E7H08

Which of the following components can be used to reduce thermal drift in crystal oscillators?

Select	Answer
A	Non-inductive resistors
B	Toroidal inductors
C	NP0 capacitors
D	Wirewound resistors

39. - E8A11

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

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

40. - E8B08

What describes Orthogonal Frequency Division Multiplexing?

Select	Answer
A	A frequency modulation technique that uses non-harmonically related frequencies
B	A digital modulation technique using subcarriers at frequencies chosen to avoid intersymbol interference
C	A digital mode for narrow-band, slow-speed transmissions
D	A bandwidth compression technique using Fourier transforms

41. - E8C03

Why should phase-shifting of a PSK signal be done at the zero crossing of the RF signal?

Select	Answer
A	To simplify modulation
B	To improve carrier suppression
C	To minimize bandwidth
D	All these choices are correct

42. - E8D09

What is considered an acceptable maximum IMD level for an idling PSK signal?

Select	Answer
A	-20 dB
B	+15 dB
C	-30 dB
D	+10 dB

43. - E9A13

What term describes station output, taking into account all gains and losses?

Select	Answer
A	Apparent power
B	Effective radiated power
C	Power factor
D	Half-power bandwidth

44. - E9B09

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

Select	Answer
A	Graphical analysis
B	Calculus differentiation with respect to physical properties
C	Mutual impedance analysis
D	Method of Moments

45. - E9C06

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

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

46. - E9D05

What usually occurs if a Yagi antenna is designed solely for maximum forward gain?

Select	Answer
A	The front-to-back ratio increases
B	The front-to-back ratio decreases
C	The frequency response is widened over the whole frequency band
D	The SWR is reduced

47. - E9E08

What is a use for a Wilkinson divider?

Select	Answer
A	It divides the operating frequency of a transmitter signal so it can be used on a lower frequency band
B	It is used to feed high-impedance antennas from a low-impedance source
C	It is used to divide power equally between two 50-ohm loads while maintaining 50-ohm input impedance
D	It is used to feed low-impedance loads from a high-impedance source

48. - E9F07

How does ladder line compare to small-diameter coaxial cable such as RG-58 at 50 MHz?

Select	Answer
A	Higher SWR
B	Smaller reflection coefficient
C	Lower velocity factor
D	Lower loss

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. - E9H05

What is the main drawback of a small wire-loop antenna for direction finding?

Select	Answer
A	All these choices are correct
B	It is practical for use only on VHF and higher bands
C	It has a bidirectional pattern
D	It has no clearly defined null