Amateur Radio Practices

E4A01 (C) How does a spectrum analyzer differ from a conventional time-domain oscilloscope?

C. A spectrum analyzer displays signals in the frequency domain; an oscilloscope displays signals in the time domain

E4A02 (D)What parameter does the horizontal axis of a spectrum analyzer display?

D. Frequency

E4A03 (A)What parameter does the vertical axis of a spectrum analyzer display?

A. Amplitude

E4A04 (A)Which test instrument is used to display spurious signals from a radio transmitter?

A. A spectrum analyzer

E4A05 (B)Which test instrument is used to display intermodulation distortion products in an SSB transmission?

B. A spectrum analyzer

E4A06 (C) Which of the following is NOT something that could be determined with a spectrum analyzer?

C. The speed at which a transceiver switches from transmit to receive when being used for packet radio

E4A07 (B)What is an advantage of using a spectrum analyzer to observe the output from a VHF transmitter?

B. It displays all frequency components of the transmitted signal

E4A08 (D)What advantage does a logic probe have over a voltmeter for monitoring the status of a logic circuit?

D. It is smaller and shows a simplified readout

E4A09 (C) Which test instrument is used to directly indicate high and low digital voltage states?

C. A logic probe

E4A10 (D)What can a logic probe indicate about a digital logic circuit?

D. The high and low logic states

E4A11 (A)Which of the following test instruments can be used to indicate pulse conditions in a digital logic circuit?

A. A logic probe

E4A12 (B)Which of the following procedures should you follow when connecting a spectrum analyzer to a transmitter output?

B. Attenuate the transmitter output going to the spectrum analyzer

E4B01 (B)What is a frequency standard?

B. A device used to produce a highly accurate reference frequency

E4B02 (B)What factors limit the accuracy, frequency response and stability of a frequency counter?

B. Time base accuracy, speed of the logic and time base stability

E4B03 (C) How can the accuracy of a frequency counter be improved?

C. By increasing the accuracy of the time base

E4B04 (C) 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?

C. 146.52 Hz

E4B05 (A)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?

A. 14.652 Hz

E4B06 (D)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?

D. 1465.20 Hz

E4B07 (D)If a frequency counter with a specified accuracy of +/- 1.0 ppm reads 432,100,000 Hz, what is the most the actual frequency being measured could differ from the reading?

D. 432.1 Hz

E4B08 (A)If a frequency counter with a specified accuracy of +/- 0.1 ppm reads 432,100,000 Hz, what is the most the actual frequency being measured could differ from the reading?

A. 43.21 Hz

E4B09 (C) If a frequency counter with a specified accuracy of +/- 10 ppm reads 432,100,000 Hz, what is the most the actual frequency being measured could differ from the reading?

C. 4321 Hz

E4B10 (C) If a 100 Hz signal is fed to the horizontal input of an oscilloscope and a 150 Hz signal is fed to the vertical input, what type of Lissajous figure will be displayed on the screen?

C. A looping pattern with 3 loops horizontally and 2 loops vertically

E4B11 (C) What is a dip-meter?

C. A device consisting of a variable frequency LC oscillator and an indicator showing the metered feedback current

E4B12 (D)What does a dip-meter do?

D. It gives an indication of the resonant frequency of a nearby circuit

E4B13 (B)How does a dip-meter function?

B. Power coupled from an oscillator causes a decrease in metered current

E4B14 (D)What two ways could a dip-meter be used in an amateur station?

D. To measure resonant frequency of antenna traps and to measure a tuned circuit resonant frequency

E4B15 (A)For best accuracy, how tightly should a dip-meter be coupled with the LC circuit being checked?

A. As loosely as possible

E4B16 (A)What factors limit the accuracy, frequency response and stability of an oscilloscope?

A. Accuracy and linearity of the time base and the linearity and bandwidth of the deflection amplifiers

E4B17 (B)What happens in a dip-meter when it is too tightly coupled with a tuned circuit being checked?

B. A less accurate reading results

E4B18 (B)What factors limit the accuracy, frequency response and stability of a D'Arsonval-type meter?

B. Calibration, mechanical tolerance and coil impedance

E4B19 (D)How can the frequency response of an oscilloscope be improved?

D. By increasing the horizontal sweep rate and the vertical amplifier frequency response

E4C01 (D)What is the effect of excessive phase noise in the local oscillator section of a receiver?

D. It allows strong signals on nearby frequencies to interfere with reception of weak signals

E4C02 (A)What is the term for the reduction in receiver sensitivity caused by a strong signal near the received frequency?

A. Desensitization

E4C03 (B)Which of the following can cause receiver desensitization?

B. Strong adjacent-channel signals

E4C04 (A)Which of the following is one way receiver desensitization can be reduced?

A. Improve the shielding between the receiver and the transmitter causing the problem

E4C05 (C) What is the FM capture effect?

C. The strongest signal received is the only demodulated signal

E4C06 (C) What is the term for the blocking of one FM phone signal by another, stronger FM phone signal?

C. Capture effect

E4C07 (D)What is meant by the noise floor of a receiver?

D. The weakest signal that can be detected above the receiver internal noise

E4C08 (B)What is the blocking dynamic range for a receiver that has an 8-dB noise figure and an IF bandwidth of 500 Hz when the blocking level (1-dB compression point) is -20 dBm?

B. 119 dB

E4C09 (C)What is meant by the dynamic range of a communications receiver?

C. The ratio between the minimum discernible signal and the largest tolerable signal without causing audible distortion products

E4C10 (A)What type of problems are caused by poor dynamic range in a communications receiver?

A. Cross modulation of the desired signal and desensitization from strong adjacent signals

E4C11 (B)If you measured the MDS of a receiver, what would you be measuring?

B. The minimum discernible signal (MDS), or the weakest signal that the receiver can detect

E4C12 (B)How does intermodulation interference between two repeater transmitters usually occur?

B. When they are in close proximity and the signals mix in one or both of their final amplifiers

E4C13 (B)How can intermodulation interference between two repeater transmitters in close proximity often be reduced or eliminated?

B. By installing a terminated circulator or ferrite isolator in the feed line to the transmitter and duplexer

E4C14 (A)If a receiver tuned to 146.70 MHz receives an intermodulation-product signal whenever a nearby transmitter transmits on 146.52 MHz, what are the two most likely frequencies for the other interfering signal?

A. 146.34 MHz and 146.61 MHz

E4C15 (D)If the signals of two transmitters mix together in one or both of their final amplifiers and unwanted signals at the sum and difference frequencies of the original signals are generated, what is this called?

D. Intermodulation interference

E4C16 (D)What is cross-modulation interference?

D. Modulation from an unwanted signal is heard in addition to the desired signal

E4C17 (C) What causes intermodulation in an electronic circuit?

C. Nonlinear circuits or devices

E4C18 (D)What two factors determine the sensitivity of a receiver?

D. Bandwidth and noise figure

E4C19 (A)What is the limiting condition for sensitivity in a communications receiver?

A. The noise floor of the receiver

E4C20 (C) Selectivity can be achieved in the front-end circuitry of a communications receiver by using what means?

C. A preselector

E4C21 (B)What degree of selectivity is desirable in the IF circuitry of an amateur RTTY receiver?

B. 300 Hz

E4C22 (B)What degree of selectivity is desirable in the IF circuitry of a single-sideband phone receiver?

B. 2.4 kHz

E4C23 (D)What is an undesirable effect of using too wide a filter bandwidth in the IF section of a receiver?

D. Undesired signals will reach the audio stage

E4C24 (A)How should the filter bandwidth of a receiver IF section compare with the bandwidth of a received signal?

A. It should be slightly greater than the received-signal bandwidth

E4C25 (D)What degree of selectivity is desirable in the IF section of an FM phone receiver?

D. 15 kHz

E4C26 (B)In a receiver, if the third-order intermodulation products have a power of-70 dBm when using two test tones at -30 dBm, what is the third-order intercept point?

B. -10 dBm

E4C27 (D)In a receiver, if the second-order intermodulation products have a power of-70 dBm when using two test tones at -30 dBm, what is the second-order intercept point?

D. +10 dBm

E4D01 (A)What is one of the most significant problems associated with reception in HF transceivers?

A. Ignition noise

E4D02 (A)What is the proper procedure for suppressing electrical noise in a mobile transceiver?

A. Follow the vehicle manufacturer's recommended procedures

E4D03 (C) Where should ferrite beads be installed to suppress ignition noise in a mobile transceiver?

C. In the primary and secondary ignition leads

E4D04 (B)How can alternator whine be minimized?

B. By connecting the radio's power leads to the battery by the shortest possible path

E4D05 (D)How can conducted and radiated noise caused by an automobile alternator be suppressed?

D. By connecting the radio's power leads directly to the battery and by installing coaxial capacitors in the alternator leads

E4D06 (B)How can noise from an electric motor be suppressed?

B. Install a brute-force, AC-line filter in series with the motor leads

E4D07 (B)What is a major cause of atmospheric static?

B. Thunderstorms

E4D08 (C) How can it be determined if line-noise interference is being generated within your home?

C. By turning off the AC power line main circuit breaker and listening on a battery-operated radio

E4D09 (A)What type of signal is picked up by electrical wiring near a radio transmitter?

A. A common-mode signal at the frequency of the radio transmitter

E4D10 (B)Which of the following types of equipment would be least useful in locating power line noise?

B. An FM receiver with a directional antenna

E4E01 (D)What circuit construction technique uses leadless components mounted between circuit board pads?

D. Surface mounting

E4E02 (A)What is the main drawback of a wire-loop antenna for direction finding?

A. It has a bidirectional pattern broadside to the loop

E4E03 (B)What pattern is desirable for a direction-finding antenna?

B. One with good front-to-back and front-to-side ratio

E4E04 (C) What is the triangulation method of direction finding?

C. Beam antenna headings from several receiving stations are used to plot the signal source on a map

E4E05 (D)Why is an RF attenuator desirable in a receiver used for direction finding?

D. It prevents receiver overload from extremely strong signals

E4E06 (A)What is a sense antenna?

A. A vertical antenna added to a loop antenna to produce a cardioid reception pattern

E4E07 (C) What is a loop antenna?

C. Several turns of wire wound in the shape of a large open coil

E4E08 (D)How can the output voltage of a loop antenna be increased?

D. By increasing either the number of wire turns in the loop or the area of the loop structure

E4E09 (B)Why is an antenna with a cardioid pattern desirable for a direction-finding system?

B. The deep null of the cardioid pattern can pinpoint the direction of the desired station

E4E10 (C) What type of terrain can cause errors in direction finding?

C. Varied terrain

E4E11 (A)What is the amateur station activity known as fox hunting?

A. Attempting to locate a hidden transmitter by using receivers and direction-finding techniques