E4 Amateur Practices

63 questions in the pool. Your exam will include 5, one from each group below.

Practice E4 now

E4A

Test equipment: analog and digital instruments; spectrum analyzers; antenna analyzers; oscilloscopes; RF measurements

• E4A01Which of the following limits the highest frequency signal that can be accurately displayed on a digital oscilloscope?
• E4A02Which of the following parameters does a spectrum analyzer display on the vertical and horizontal axes?
• E4A03Which of the following test instruments is used to display spurious signals and/or intermodulation distortion products generated by an SSB transmitter?
• E4A04How is compensation of an oscilloscope probe performed?
• E4A05What is the purpose of using a prescaler with a frequency counter?
• E4A06What is the effect of aliasing on a digital oscilloscope when displaying a waveform?
• E4A07Which of the following is an advantage of using an antenna analyzer compared to an SWR bridge?
• E4A08Which of the following is used to measure SWR?
• E4A09Which of the following is good practice when using an oscilloscope probe?
• E4A10Which trigger mode is most effective when using an oscilloscope to measure a linear power supply's output ripple?
• E4A11Which of the following can be measured with an antenna analyzer?

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; RF signals

• E4B01Which of the following factors most affects the accuracy of a frequency counter?
• E4B02What is the significance of voltmeter sensitivity expressed in ohms per volt?
• E4B03Which S parameter is equivalent to forward gain?
• E4B04Which S parameter represents input port return loss or reflection coefficient (equivalent to VSWR)?
• E4B05What three test loads are used to calibrate an RF vector network analyzer?
• E4B06How 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?
• E4B07What do the subscripts of S parameters represent?
• E4B08Which of the following can be used to determine the Q of a series-tuned circuit?
• E4B09Which of the following can be measured by a two-port vector network analyzer?
• E4B10Which of the following methods measures intermodulation distortion in an SSB transmitter?
• E4B11Which of the following can be measured with a vector network analyzer?

E4C

Receiver performance: phase noise, noise floor, image rejection, minimum detectable signal (MDS), increasing signal-to-noise ratio and dynamic range, noise figure, reciprocal mixing; selectivity; SDR non- linearity; use of attenuators at low frequencies

• E4C01What is an effect of excessive phase noise in an SDR receiver's master clock oscillator?
• E4C02Which of the following receiver circuits can be effective in eliminating interference from strong out-of-band signals?
• E4C03What is the term for the suppression in an FM receiver of one signal by another stronger signal on the same frequency?
• E4C04What is the noise figure of a receiver?
• E4C05What does a receiver noise floor of -174 dBm represent?
• E4C06How much does increasing a receiver's bandwidth from 50 Hz to 1,000 Hz increase the receiver's noise floor?
• E4C07What does the MDS of a receiver represent?
• E4C08An SDR receiver is overloaded when input signals exceed what level?
• E4C09Which of the following choices is a good reason for selecting a high IF for a superheterodyne HF or VHF communications receiver?
• E4C10What is an advantage of having a variety of receiver bandwidths from which to select?
• E4C11Why does input attenuation reduce receiver overload on the lower frequency HF bands with little or no impact on signal-to-noise ratio?
• E4C12How does a narrow-band roofing filter affect receiver performance?
• E4C13What is reciprocal mixing?
• E4C14What is the purpose of the receiver IF Shift control?

E4D

Receiver performance characteristics: dynamic range; intermodulation and cross-modulation interference; third-order intercept; desensitization; preselector; sensitivity; link margin

• E4D01What is meant by the blocking dynamic range of a receiver?
• E4D02Which of the following describes problems caused by poor dynamic range in a receiver?
• E4D03What creates intermodulation interference between two repeaters in close proximity?
• E4D04Which of the following is used to reduce or eliminate intermodulation interference in a repeater caused by a nearby transmitter?
• E4D06What is the term for the reduction in receiver sensitivity caused by a strong signal near the received frequency?
• E4D07Which of the following reduces the likelihood of receiver desensitization?
• E4D08What causes intermodulation in an electronic circuit?
• E4D09What is the purpose of the preselector in a communications receiver?
• E4D10What does a third-order intercept level of 40 dBm mean with respect to receiver performance?
• E4D11Why are odd-order intermodulation products, created within a receiver, of particular interest compared to other products?
• E4D12What is the link margin in a system with a transmit power level of 10 W (+40 dBm), a system antenna gain of 10 dBi, a cable loss of 3 dB, a path loss of 136 dB, a receiver minimum discernable signal of -103 dBm, and a required signal-to-noise ratio of 6 dB?
• E4D13What is the received signal level with a transmit power of 10 W (+40 dBm), a transmit antenna gain of 6 dBi, a receive antenna gain of 3 dBi, and a path loss of 100 dB?
• E4D14What power level does a receiver minimum discernible signal of -100 dBm represent?

E4E

Noise and interference: external RF interference; electrical and computer noise; line noise; DSP filtering and noise reduction; common-mode current; surge protectors; single point ground panel

• E4E01What problem can occur when using an automatic notch filter (ANF) to remove interfering carriers while receiving CW signals?
• E4E02Which of the following types of noise can often be reduced by a digital noise reduction?
• E4E03Which of the following types of noise are removed by a noise blanker?
• E4E04How can conducted noise from an automobile battery charging system be suppressed?
• E4E05What is used to suppress radio frequency interference from a line-driven AC motor?
• E4E06What type of electrical interference can be caused by computer network equipment?
• E4E07Which of the following can cause shielded cables to radiate or receive interference?
• E4E08What current flows equally on all conductors of an unshielded multiconductor cable?
• E4E09What undesirable effect can occur when using a noise blanker?
• E4E10Which of the following can create intermittent loud roaring or buzzing AC line interference?
• E4E11What could be the cause of local AM broadcast band signals combining to generate spurious signals on the MF or HF bands?
• E4E12What causes interference received as a series of carriers at regular intervals across a wide frequency range?
• E4E13Where should a station AC surge protector be installed?
• E4E14What is the purpose of a single point ground panel?