Extra Class License Exam Questions

Subelement E4

Amateur Practices

Question Display Options:
Group E4A Test equipment: analog and digital instruments; spectrum and network analyzers, antenna analyzers; oscilloscopes; RF measurements; computer aided measurements
E4A01 Which of the following parameter determines the bandwidth of a digital or computer-based oscilloscope?
E4A02 Which of the following parameters would a spectrum analyzer display on the vertical and horizontal axes?
E4A03 Which of the following test instrument is used to display spurious signals and/or intermodulation distortion products in an SSB transmitter?
E4A04 What determines the upper frequency limit for a computer soundcard-based oscilloscope program?
E4A05 What might be an advantage of a digital vs an analog oscilloscope?
E4A06 What is the effect of aliasing in a digital or computer-based oscilloscope?
E4A07 Which of the following is an advantage of using an antenna analyzer compared to an SWR bridge to measure antenna SWR?
E4A08 Which of the following instrument would be best for measuring the SWR of a beam antenna?
E4A09 When using a computer’s soundcard input to digitize signals, what is the highest frequency signal that can be digitized without aliasing?
E4A10 Which of the following displays multiple digital signal states simultaneously?
E4A11 Which of the following is good practice when using an oscilloscope probe?
E4A12 Which of the following procedures is an important precaution to follow when connecting a spectrum analyzer to a transmitter output?
E4A13 How is the compensation of an oscilloscope probe typically adjusted?
E4A14 What is the purpose of the prescaler function on a frequency counter?
E4A15 What is an advantage of a period-measuring frequency counter over a direct-count type?
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Group E4B Measurement technique and limitations: instrument accuracy and performance limitations; probes; techniques to minimize errors; measurement of "Q"; instrument calibration; S parameters; vector network analyzers
E4B01 Which of the following factors most affects the accuracy of a frequency counter?
E4B02 What is an advantage of using a bridge circuit to measure impedance?
E4B03 If a frequency counter with a specified accuracy of +/- 1.0 ppm reads 146,520,000 Hz, what is the most the actual frequency being measured could differ from the reading?
E4B04 If a frequency counter with a specified accuracy of +/- 0.1 ppm reads 146,520,000 Hz, what is the most the actual frequency being measured could differ from the reading?
E4B05 If a frequency counter with a specified accuracy of +/- 10 ppm reads 146,520,000 Hz, what is the most the actual frequency being measured could differ from the reading?
E4B06 How much power is being absorbed by the load when a directional power meter connected between a transmitter and a terminating load reads 100 watts forward power and 25 watts reflected power?
E4B07 What do the subscripts of S parameters represent?
E4B08 Which of the following is a characteristic of a good DC voltmeter?
E4B09 What is indicated if the current reading on an RF ammeter placed in series with the antenna feed line of a transmitter increases as the transmitter is tuned to resonance?
E4B10 Which of the following describes a method to measure intermodulation distortion in an SSB transmitter?
E4B11 How should an antenna analyzer be connected when measuring antenna resonance and feed point impedance?
E4B12 What is the significance of voltmeter sensitivity expressed in ohms per volt?
E4B13 Which S parameter is equivalent to forward gain?
E4B14 What happens if a dip meter is too tightly coupled to a tuned circuit being checked?
E4B15 Which of the following can be used as a relative measurement of the Q for a series-tuned circuit?
E4B16 Which S parameter represents return loss or SWR?
E4B17 What three test loads are used to calibrate a standard RF vector network analyzer?
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Group E4C Receiver performance characteristics, phase noise, noise floor, image rejection, MDS, signal-to-noise-ratio; selectivity; effects of SDR receiver non-linearity
E4C01 What is an effect of excessive phase noise in the local oscillator section of a receiver?
E4C02 Which of the following portions of a receiver can be effective in eliminating image signal interference?
E4C03 What is the term for the blocking of one FM phone signal by another, stronger FM phone signal?
E4C04 How is the noise figure of a receiver defined?
E4C05 What does a value of -174 dBm/Hz represent with regard to the noise floor of a receiver?
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?
E4C07 What does the MDS of a receiver represent?
E4C08 An SDR receiver is overloaded when input signals exceed what level?
E4C09 Which of the following choices is a good reason for selecting a high frequency for the design of the IF in a conventional HF or VHF communications receiver?
E4C10 Which of the following is a desirable amount of selectivity for an amateur RTTY HF receiver?
E4C11 Which of the following is a desirable amount of selectivity for an amateur SSB phone receiver?
E4C12 What is an undesirable effect of using too wide a filter bandwidth in the IF section of a receiver?
E4C13 How does a narrow-band roofing filter affect receiver performance?
E4C14 What transmit frequency might generate an image response signal in a receiver tuned to 14.300 MHz and which uses a 455 kHz IF frequency?
E4C15 What is usually the primary source of noise that is heard from an HF receiver with an antenna connected?
E4C16 Which of the following is caused by missing codes in an SDR receiver’s analog-to-digital converter?
E4C17 Which of the following has the largest effect on an SDR receiver’s linearity?
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Group E4D Receiver performance characteristics: blocking dynamic range; intermodulation and cross-modulation interference; 3rd order intercept; desensitization; preselector
E4D01 What is meant by the blocking dynamic range of a receiver?
E4D02 Which of the following describes two problems caused by poor dynamic range in a communications receiver?
E4D03 How can intermodulation interference between two repeaters occur?
E4D04 Which of the following may reduce or eliminate intermodulation interference in a repeater caused by another transmitter operating in close proximity?
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?
E4D06 What is the term for unwanted signals generated by the mixing of two or more signals?
E4D07 Which describes the most significant effect of an off-frequency signal when it is causing cross-modulation interference to a desired signal?
E4D08 What causes intermodulation in an electronic circuit?
E4D09 What is the purpose of the preselector in a communications receiver?
E4D10 What does a third-order intercept level of 40 dBm mean with respect to receiver performance?
E4D11 Why are third-order intermodulation products created within a receiver of particular interest compared to other products?
E4D12 What is the term for the reduction in receiver sensitivity caused by a strong signal near the received frequency?
E4D13 Which of the following can cause receiver desensitization?
E4D14 Which of the following is a way to reduce the likelihood of receiver desensitization?
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Group E4E Noise suppression: system noise; electrical appliance noise; line noise; locating noise sources; DSP noise reduction; noise blankers; grounding for signals
E4E01 Which of the following types of receiver noise can often be reduced by use of a receiver noise blanker?
E4E02 Which of the following types of receiver noise can often be reduced with a DSP noise filter?
E4E03 Which of the following signals might a receiver noise blanker be able to remove from desired signals?
E4E04 How can conducted and radiated noise caused by an automobile alternator be suppressed?
E4E05 How can noise from an electric motor be suppressed?
E4E06 What is a major cause of atmospheric static?
E4E07 How can you determine if line noise interference is being generated within your home?
E4E08 What type of signal is picked up by electrical wiring near a radio antenna?
E4E09 What undesirable effect can occur when using an IF noise blanker?
E4E10 What is a common characteristic of interference caused by a touch controlled electrical device?
E4E11 Which is the most likely cause if you are hearing combinations of local AM broadcast signals within one or more of the MF or HF ham bands?
E4E12 What is one disadvantage of using some types of automatic DSP notch-filters when attempting to copy CW signals?
E4E13 What might be the cause of a loud roaring or buzzing AC line interference that comes and goes at intervals?
E4E14 What is one type of electrical interference that might be caused by the operation of a nearby personal computer?
E4E15 Which of the following can cause shielded cables to radiate or receive interference?
E4E16 What current flows equally on all conductors of an unshielded multi-conductor cable?
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