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

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1. - E0A09

Which insulating material commonly used as a thermal conductor for some types of electronic devices is extremely toxic if broken or crushed and the particles are accidentally inhaled?

Select	Answer
A	Uranium Hexafluoride
B	Zinc oxide
C	Mica
D	Beryllium Oxide

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. - E1B11

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

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

4. - E1C01

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

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

5. - E1D05

What must be posted at the station location of a station being operated by telecommand on or within 50 km of the earth's surface?

Select	Answer
A	A label with the name, address, and telephone number of the control operator
B	A photocopy of the station license
C	A label with the name, address, and telephone number of the station licensee
D	All these choices are correct

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?

Select	Answer
A	Three VEs must certify that the examinee is qualified for the license grant and that they have complied with the administering VE requirements
B	Photocopy all examination documents and forward them to the FCC for processing
C	All these choices are correct
D	Issue the examinee the new or upgrade license

7. - E1F06

Under what circumstances might the FCC issue a Special Temporary Authority (STA) to an amateur station?

Select	Answer
A	To allow regular operation on Land Mobile channels
B	To provide for experimental amateur communications
C	To provide temporary operation while awaiting normal licensing
D	To provide additional spectrum for personal use

8. - E2A02

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

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

9. - E2B02

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

Select	Answer
A	1080
B	60
C	30
D	525

10. - E2C04

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

Select	Answer
A	HF frequencies where digital communications are permitted
B	Frequencies shared with various unlicensed wireless data services
C	The 60 meter band channel centered on 5373 kHz
D	Cable TV channels 41 through 43

11. - E2D01

Which of the following digital modes is designed for meteor scatter communications?

Select	Answer
A	MSK144
B	Hellschreiber
C	APRS
D	WSPR

12. - E2E05

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

Select	Answer
A	PACTOR
B	MFSK
C	RTTY
D	PSK31

13. - E3A04

What do Hepburn maps predict?

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

14. - E3B09

At what time of year is sporadic E propagation most likely to occur?

Select	Answer
A	Around the equinoxes, especially the spring equinox
B	Around the equinoxes, especially the fall equinox
C	Around the solstices, especially the winter solstice
D	Around the solstices, especially the summer solstice

15. - E3C02

What is indicated by a rising A or K index?

Select	Answer
A	An increase in the critical frequency
B	Decreasing disruption of the geomagnetic field
C	Increasing disruption of the geomagnetic field
D	Higher levels of solar UV radiation

16. - E4A01

Which of the following limits the highest frequency signal that can be accurately displayed on a digital oscilloscope?

Select	Answer
A	All these choices are correct
B	Sampling rate of the analog-to-digital converter
C	Amount of memory
D	Q of the circuit

17. - E4B03

Which S parameter is equivalent to forward gain?

Select	Answer
A	S22
B	S11
C	S21
D	S12

18. - E4C03

What is the term for the suppression in an FM receiver of one signal by another stronger signal on the same frequency?

Select	Answer
A	Capture effect
B	Cross-modulation interference
C	Desensitization
D	Frequency discrimination

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	146.34 MHz and 146.61 MHz
C	146.10 MHz and 147.30 MHz
D	146.88 MHz and 146.34 MHz

20. - E4E04

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

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

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	7.12 MHz
C	23.5 MHz
D	23.5 kHz

22. - E5B12

What is admittance?

Select	Answer
A	The turns ratio of a transformer
B	The inverse of impedance
C	The inverse of Q factor
D	The term for the gain of a field effect transistor

23. - E5C05

What is the name of the diagram used to show the phase relationship between impedances at a given frequency?

Select	Answer
A	Venn diagram
B	Phasor diagram
C	Near field diagram
D	Far field diagram

24. - E5D10

How can the true power be determined in an AC circuit where the voltage and current are out of phase?

Select	Answer
A	By multiplying the reactive power by the power factor
B	By dividing the reactive power by the power factor
C	By dividing the apparent power by the power factor
D	By multiplying the apparent power by the power factor

25. - E6A05

How does DC input impedance at the gate of a field-effect transistor compare with the DC input impedance of a bipolar transistor?

Select	Answer
A	They are both high impedance
B	An FET has higher input impedance
C	They are both low impedance
D	An FET has lower input impedance

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

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 allow the comparator to be used with AC input signals
C	To increase the sensitivity
D	To cause the output to change states continually

28. - E6D03

Which of the following is an aspect of the piezoelectric effect?

Select	Answer
A	Generation of electrical energy in the presence of light
B	Increased conductivity in the presence of light
C	Mechanical deformation of material by the application of a voltage
D	Mechanical deformation of material by the application of a magnetic field

29. - E6E05

Which of the following noise figure values is typical of a low-noise UHF preamplifier?

Select	Answer
A	-20 dBm
B	44 dBm
C	-10 dB
D	2 dB

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. - E7A09

What logical operation is performed by an exclusive NOR gate?

Select	Answer
A	It produces logic 0 at its output if only one input is logic 1
B	It produces logic 1 at its output only if all inputs are logic 1
C	It produces logic 0 at its output only if all inputs are logic 0
D	It produces logic 1 at its output if only one input is logic 1

32. - E7B04

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

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

33. - E7C03

What advantage does a series-L Pi-L-network have over a series-L Pi-network for impedance matching between the final amplifier of a vacuum-tube transmitter and an antenna?

Select	Answer
A	Higher efficiency
B	Does not require a capacitor
C	Greater transformation range
D	Greater harmonic suppression

34. - E7D15

What is the purpose of a step-start circuit in a high-voltage power supply?

Select	Answer
A	To compensate for variations of the incoming line voltage
B	To provide a dual-voltage output for reduced power applications
C	To allow the filter capacitors to charge gradually
D	To allow for remote control of the power supply

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

36. - E7F14

Which of the following would allow a digital signal processing filter to create a sharper filter response?

Select	Answer
A	Double-precision math routines
B	Complex phasor representations
C	Higher data rate
D	More taps

37. - E7G05

How can unwanted ringing and audio instability be prevented in an op-amp RC audio filter circuit?

Select	Answer
A	Increase both gain and Q
B	Restrict gain but increase Q
C	Restrict Q but increase gain
D	Restrict both gain and Q

38. - E7H12

Which of the following must be done to ensure that a crystal oscillator provides the frequency specified by the crystal manufacturer?

Select	Answer
A	Bias the crystal at a specified current
B	Provide the crystal with a specified parallel inductance
C	Bias the crystal at a specified voltage
D	Provide the crystal with a specified parallel capacitance

39. - E8A11

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

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

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	0.167
B	60
C	0.6
D	1.67

41. - E8C03

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

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

42. - E8D03

How does the spread spectrum technique of frequency hopping work?

Select	Answer
A	If interference is detected by the receiver it will signal the transmitter to change frequencies
B	The frequency of the transmitted signal is changed very rapidly according to a pseudorandom sequence also used by the receiving station
C	A binary bit stream is used to shift the phase of an RF carrier very rapidly in a pseudorandom sequence
D	If interference is detected by the receiver it will signal the transmitter to wait until the frequency is clear

43. - E9A10

Which of the following improves the efficiency of a ground-mounted quarter-wave vertical antenna?

Select	Answer
A	All these choices are correct
B	Installing a radial system
C	Isolating the coax shield from ground
D	Shortening the radiating element

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. - E9C07

What is the approximate feed point impedance at the center of a two-wire folded dipole antenna?

Select	Answer
A	50 ohms
B	72 ohms
C	300 ohms
D	450 ohms

46. - E9D05

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

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

47. - E9E07

What parameter describes the interactions at the load end of a mismatched transmission line?

Select	Answer
A	Reflection coefficient
B	Dielectric constant
C	Characteristic impedance
D	Velocity factor

48. - E9F08

Which of the following is a significant difference between foam dielectric coaxial cable and solid dielectric cable, assuming all other parameters are the same?

Select	Answer
A	Foam dielectric has higher velocity factor
B	Foam dielectric has lower loss per unit of length
C	All these choices are correct
D	Foam dielectric has lower safe operating voltage limits

49. - E9G11

How are the wavelength scales on a Smith chart calibrated?

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

50. - E9H07

Why is RF attenuation used when direction-finding?

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