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

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1. - E0A01

What is the primary function of an external earth connection or ground rod?

Select	Answer
A	Lightning protection
B	Reduce RFI to telephones and home entertainment systems
C	Reduce received noise
D	Reduce RF current flow between pieces of equipment

2. - E1A08

If a station in a message forwarding system inadvertently forwards a message that is in violation of FCC rules, who is primarily accountable for the rules violation?

Select	Answer
A	The control operator of the originating station
B	The control operators of all the stations in the system
C	The control operators of all the stations in the system not authenticating the source from which they accept communications
D	The control operator of the packet bulletin board station

3. - E1B11

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

Select	Answer
A	Amateur radio operations must be permitted in any private residence
B	Use of wireless devices in a vehicle is exempt from regulation
C	Reasonable accommodations of amateur radio must be made
D	No limitations may be placed on antenna size or placement

4. - E1C09

What is the highest modulation index permitted at the highest modulation frequency for angle modulation below 29.0 MHz?

Select	Answer
A	2.0
B	0.5
C	1.0
D	3.0

5. - E1D09

Which UHF amateur bands have frequencies authorized for space stations?

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

6. - E1E08

To which of the following examinees may a VE not administer an examination?

Select	Answer
A	Friends of the VE
B	Relatives of the VE as listed in the FCC rules
C	All these choices are correct
D	Employees of the VE

7. - E1F09

Which of the following conditions apply when transmitting spread spectrum emissions?

Select	Answer
A	The transmitting station must be in an area regulated by the FCC or in a country that permits SS emissions
B	All these choices are correct
C	A station transmitting SS emission must not cause harmful interference to other stations employing other authorized emissions
D	The transmission must not be used to obscure the meaning of any communication

8. - E2A11

What type of antenna can be used to minimize the effects of spin modulation and Faraday rotation?

Select	Answer
A	A log-periodic dipole array
B	An isotropic antenna
C	A linearly polarized antenna
D	A circularly polarized antenna

9. - E2B10

What aspect of an analog slow-scan television signal encodes the brightness of the picture?

Select	Answer
A	Tone amplitude
B	Tone frequency
C	Sync amplitude
D	Sync frequency

10. - E2C07

What is the Cabrillo format?

Select	Answer
A	The most common set of contest rules
B	A method of exchanging information during a contest QSO
C	The rules of order for meetings between contest sponsors
D	A standard for submission of electronic contest logs

11. - E2D04

What technology is used to track, in real time, balloons carrying amateur radio transmitters?

Select	Answer
A	Doppler shift of beacon signals
B	Ultrasonics
C	Bandwidth compressed LORAN
D	APRS

12. - E2E05

Which of these digital modes does not support keyboard-to-keyboard operation?

Select	Answer
A	RTTY
B	PACTOR
C	MFSK
D	PSK31

13. - E3A04

What do Hepburn maps predict?

Select	Answer
A	Probability of tropospheric propagation
B	Sporadic E propagation
C	Locations of auroral reflecting zones
D	Likelihood of rain scatter along cold or warm fronts

14. - E3B12

What is the primary characteristic of chordal hop propagation?

Select	Answer
A	Successive ionospheric refractions without an intermediate reflection from the ground
B	Propagation across the geomagnetic equator
C	Signals reflected back toward the transmitting station
D	Propagation away from the great circle bearing between stations

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. - E4A06

What is the effect of aliasing on a digital oscilloscope caused by setting the time base too slow?

Select	Answer
A	Excessive blanking occurs, which prevents display of the signal
B	Calibration of the vertical scale is no longer valid
C	A false, jittery low-frequency version of the signal is displayed
D	All signals will have a DC offset

17. - E4B10

Which of the following methods measures intermodulation distortion in an SSB transmitter?

Select	Answer
A	Modulate the transmitter using two AF signals having non-harmonically related frequencies and observe the RF output with a spectrum analyzer
B	Modulate the transmitter using two AF signals having harmonically related frequencies and observe the RF output with a peak reading wattmeter
C	Modulate the transmitter using two RF signals having harmonically related frequencies and observe the RF output with a logic analyzer
D	Modulate the transmitter using two RF signals having non-harmonically related frequencies and observe the RF output with a spectrum analyzer

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	-155 dBm
B	-174 dBm
C	-164 dBm
D	-148 dBm

19. - E4D03

How can intermodulation interference between two repeaters occur?

Select	Answer
A	When the signals from the transmitters are reflected in phase from airplanes passing overhead
B	When the signals from the transmitters are reflected out of phase from airplanes passing overhead
C	When the repeaters are in close proximity and the signals cause feedback in the final amplifier of one or both transmitters
D	When the repeaters are in close proximity and the signals mix in the final amplifier of one or both transmitters

20. - E4E07

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

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

21. - E5A06

What is the magnitude of the circulating current within the components of a parallel LC circuit at resonance?

Select	Answer
A	It equals 2 multiplied by pi, multiplied by frequency, multiplied by inductance
B	It is at a maximum
C	It is at a minimum
D	It equals 1 divided by the quantity 2 times pi, multiplied by the square root of inductance L multiplied by capacitance C

22. - E5B02

What letter is commonly used to represent susceptance?

Select	Answer
A	Y
B	B
C	G
D	X

23. - E5C02

How are impedances described in polar coordinates?

Select	Answer
A	By X and R values
B	By phase angle and magnitude
C	By real and imaginary parts
D	By Y and G values

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	50 watts
B	400 watts
C	80 watts
D	2000 watts

25. - E6A04

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

Select	Answer
A	Insulator impurity
B	N-type impurity
C	Acceptor impurity
D	Donor impurity

26. - E6B03

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

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

27. - E6C04

Which of the following is an advantage of BiCMOS logic?

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

28. - E6D11

Which type of core material decreases inductance when inserted into a coil?

Select	Answer
A	Ceramic
B	Ferrite
C	Powdered iron
D	Brass

29. - E6E08

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

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

30. - E6F05

Which describes an optical shaft encoder?

Select	Answer
A	A device that 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 that 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

31. - E7A01

Which circuit is bistable?

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

32. - E7B04

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

Select	Answer
A	Where the load line intersects the voltage axis
B	At a point where the load line intersects the zero bias current curve
C	At a point where the bias resistor equals the load resistor
D	Approximately halfway between saturation and cutoff

33. - E7C02

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

Select	Answer
A	It is a band-pass filter
B	It is a notch filter
C	It is a low-pass filter
D	It is a high-pass filter

34. - E7D07

What is the purpose of C2 in the circuit shown in Figure E7-2?

Select	Answer
A	It bypasses rectifier output ripple around D1
B	To self-resonate at the hum frequency
C	It is a brute force filter for the output
D	To provide fixed DC bias for Q1

35. - E7E10

How does a diode envelope detector function?

Select	Answer
A	By breakdown of the Zener voltage
B	By mixing signals with noise in the transition region of the diode
C	By rectification and filtering of RF signals
D	By sensing the change of reactance in the diode with respect to frequency

36. - E7F05

How frequently must an analog signal be sampled by an analog-to-digital converter so that the signal can be accurately reproduced?

Select	Answer
A	At the same rate as the highest frequency component of the signal
B	At least twice the rate of the highest frequency component of the signal
C	At least half the rate of the highest frequency component of the signal
D	At four times the rate of the highest frequency component of the signal

37. - E7G01

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

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

38. - E7H11

What are the major spectral impurity components of direct digital synthesizers?

Select	Answer
A	Nyquist limit noise
B	Spurious signals at discrete frequencies
C	Digital conversion noise
D	Broadband noise

39. - E8A09

How many different input levels can be encoded by an analog-to-digital converter with 8-bit resolution?

Select	Answer
A	256 divided by the gain of the input amplifier
B	8 multiplied by the gain of the input amplifier
C	256
D	8

40. - E8B07

Orthogonal Frequency Division Multiplexing is a technique used for which type of amateur communication?

Select	Answer
A	EME
B	High-speed digital modes
C	OFDM signals are not allowed on amateur bands
D	Extremely low-power contacts

41. - E8C04

What technique minimizes the bandwidth of a PSK31 signal?

Select	Answer
A	Use of sinusoidal data pulses
B	Use of trapezoidal data pulses
C	Zero-sum character encoding
D	Reed-Solomon character encoding

42. - E8D06

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

Select	Answer
A	Some types of errors can be detected
B	The signal can overpower interfering signals
C	Faster transmission rate
D	Foreign language characters can be sent

43. - E9A09

What is antenna efficiency?

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

44. - E9B02

In the antenna radiation pattern shown in Figure E9-1, what is the front-to-back ratio?

Select	Answer
A	36 dB
B	18 dB
C	14 dB
D	24 dB

45. - E9C09

Which of the following describes a G5RV antenna?

Select	Answer
A	A multi-band dipole antenna fed with coax and a balun through a selected length of open wire transmission line
B	A wide band dipole using shorted coaxial cable for the radiating elements and fed with a�4:1 balun
C	A multi-band trap antenna
D	A phased array antenna consisting of multiple loops

46. - E9D11

Which of the following conductors would be best for minimizing losses in a station's RF ground system?

Select	Answer
A	Solid wire
B	Resistive wire, such as spark plug wire
C	Stranded wire
D	Wide flat copper strap

47. - E9E04

What is the purpose of the series capacitor in a gamma-type antenna matching network?

Select	Answer
A	To transform the antenna impedance to a higher value
B	To provide a rejection notch that prevents the radiation of harmonics
C	To cancel the inductive reactance of the matching network
D	To provide DC isolation between the feed line and the antenna

48. - E9F04

What impedance does a 1/2-wavelength transmission line present to a generator when the line is shorted at the far end?

Select	Answer
A	The same as the characteristic impedance of the line
B	Very low impedance
C	Very high impedance
D	The same as the output impedance of the generator

49. - E9G05

Which of the following is a common use for a Smith chart?

Select	Answer
A	Determine the gain of an antenna given the physical and electrical parameters
B	Determine the length and position of an impedance matching stub
C	Determine the loss/100 feet of a transmission line, given the velocity factor and conductor materials
D	Determine the impedance of a transmission line, given the physical dimensions

50. - E9H09

What is a Pennant antenna?

Select	Answer
A	A four-element, high-gain vertical array invented by George Pennant
B	A form of rhombic antenna terminated in a variable capacitor to provide frequency diversity
C	A stealth antenna built to look like a flagpole
D	A small, vertically oriented receiving antenna consisting of a triangular loop terminated in approximately 900 ohms

Figure E7-2

Figure E9-1