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Text File | 1992-01-26 | 16KB | 564 lines

FCC GENERAL Exam Question Pool. Subelement 3BD. Amateur Radio Practice. ? Questions. --------------------------------------------------- 3BD 1.5 A Which wires in a four conductor line cord should be attached to fuses in a 234-VAC primary (single phase) power supply? A. Only the "hot" (black and red) wires B. Only the "neutral" (white) wire C. Only the ground (bare) wire D. All wires 3BD 1.6 A What size wire is normally used on a 15-ampere, 117-VAC household lighting circuit? A. AWG number 14 B. AWG number 16 C. AWG number 18 D. AWG number 22 3BD 1.7 D What size wire is normally used on a 20-ampere, 117-VAC household appliance circuit? A. AWG number 20 B. AWG number 16 C. AWG number 14 D. AWG number 12 3BD 1.8 C What could be a cause of the room lights dimming when the transmitter is keyed? A. RF in the AC pole transformer B. High resistance in the key contacts C. A drop in AC line voltage D. The line cord is wired incorrectly 3BD 1.9 D What size fuse should be used on a #12 wire household appliance circuit? A. Maximum of 100 amperes B. Maximum of 60 amperes C. Maximum of 30 amperes D. Maximum of 20 amperes 3BD 2.4 B What safety feature is provided by a bleeder resistor in a power supply? A. It improves voltage regulation B. It discharges the filter capacitors C. It removes shock hazards from the induction coils D. It eliminates ground-loop current 3BD 3.1 C What kind of input signal is used to test the amplitude linearity of a single-sideband phone transmitter while viewing the output on an oscilloscope? A. Normal speech B. An audio-frequency sine wave C. Two audio-frequency sine waves D. An audio-frequency square wave 3BD 3.2 C To test the amplitude linearity of a single-sideband phone transmitter with an oscilloscope, what should the audio input to the transmitter be? A. Normal speech B. An audio-frequency sine wave C. Two audio-frequency sine waves D. An audio-frequency square wave 3BD 3.3 C How are two tones used to test the amplitude linearity of a single- sideband phone transmitter? A. Two harmonically related audio tones are fed into the micro- phone input of the transmitter, and the output is observed on an oscilloscope B. Two harmonically related audio tones are fed into the micro- phone input of the transmitter, and the output is observed on a distortion analyzer C. Two non-harmonically related audio tones are fed into the microphone input of the transmitter, and the output is observed on an oscilloscope D. Two non-harmonically related audio tones are fed into the microphone input of the transmitter, and the output is observed on a wattmeter 3BD 3.4 D What audio frequencies are used in a two-tone test of the linearity of a single-sideband phone transmitter? A. 20 Hz and 20,000 Hz tones must be used B. 1200 Hz and 2400 Hz tones must be used C. Any two audio tones may be used, but they must be within the transmitter audio passband, and must be harmonically related D. Any two audio tones may be used, but they must be within the transmitter audio passband, and should not be harmonically related 3BD 3.5 D What can be determined by making a two-tone test using an oscilloscope? A. The percent of frequency modulation B. The percent of carrier phase shift C. The frequency deviation D. The amplifier linearity 3BD 4.1 A How can the grid-current meter in a power amplifier be used as a neutralizing indicator? A. Tune for minimum change in grid current as the output circuit is changed B. Tune for maximum change in grid current as the output circuit is changed C. Tune for minimum grid current D. Tune for maximum grid current 3BD 4.2 D Why is neutralization in some vacuum tube amplifiers necessary? A. To reduce the limits of loaded Q in practical tuned circuits B. To reduce grid to cathode leakage C. To cancel acid build-up caused by thorium oxide gas D. To cancel oscillation caused by the effects of interelectrode capacitance 3BD 4.3 C How is neutralization of an RF amplifier accomplished? A. By supplying energy from the amplifier output to the input on alternate half cycles B. By supplying energy from the amplifier output to the input shifted 360 degrees out of phase C. By supplying energy from the amplifier output to the input shifted 180 degrees out of phase D. By supplying energy from the amplifier output to the input with a proper DC bias 3BD 4.4 B What purpose does a neutralizing circuit serve in an RF amplifier? A. It controls differential gain B. It cancels the effects of positive feedback C. It eliminates circulating currents D. It reduces incidental grid modulation 3BD 4.5 B What is the reason for neutralizing the final amplifier stage of a transmitter? A. To limit the modulation index B. To eliminate parasitic oscillations C. To cut off the final amplifier during standby periods D. To keep the carrier on frequency 3BD 5.1 B How can the output PEP of a transmitter be determined with an oscilloscope? A. Measure peak load voltage across a resistive load with an oscilloscope, and calculate, using PEP = [(Vp)(Vp)] / (RL) B. Measure peak load voltage across a resistive load with an oscilloscope, and calculate, using PEP = [(0.707 PEV)(0.707 PEV)] / RL C. Measure peak load voltage across a resistive load with an oscilloscope, and calculate, using PEP = (Vp)(Vp)(RL) D. Measure peak load voltage across a resistive load with an oscilloscope, and calculate, using PEP = [(1.414 PEV)(1.414 PEV)] / RL 3BD 5.5 A What is the output PEP from a transmitter when an oscilloscope shows 200-volts peak-to-peak across a 50 ohm resistor connected to the transmitter output terminals? A. 100 watts B. 200 watts C. 400 watts D. 1000 watts 3BD 5.6 B What is the output PEP from a transmitter when an oscilloscope shows 500-volts peak-to-peak across a 50 ohm resistor connected to the transmitter output terminals? A. 500 watts B. 625 watts C. 1250 watts D. 2500 watts 3BD 5.7 B What is the output PEP of an unmodulated carrier transmitter when an average-reading wattmeter connected to the transmitter output terminals indicates 1060 watts? A. 530 watts B. 1060 watts C. 1500 watts D. 2120 watts 3BD 6.1 D What item of test equipment contains horizontal and vertical channel amplifiers? A. The ohmmeter B. The signal generator C. The ammeter D. The oscilloscope 3BD 6.2 A What types of signals can an oscilloscope measure? A. Any time-dependent signal within the bandwidth capability of the instrument B. Blinker-light signals from ocean-going vessels C. International nautical flag signals D. Signals created by aeronautical flares 3BD 6.3 D What is an oscilloscope? A. An instrument that displays the radiation resistance of an antenna B. An instrument that displays the SWR on a feed line C. An instrument that displays the resistance in a circuit D. An instrument that displays signal waveforms 3BD 6.4 B What can cause phosphor damage to an oscilloscope cathode ray tube? A. Directly connecting deflection electrodes to the cathode ray tube B. Too high an intensity setting C. Overdriving the vertical amplifier D. Improperly adjusted focus 3BD 9.1 C What is a signal tracer? A. A direction-finding antenna B. An aid for following schematic diagrams C. A device for detecting signals in a circuit D. A device for drawing signal waveforms 3BD 9.2 A How is a signal tracer used? A. To detect the presence of a signal in the various stages of a receiver B. To locate a source of interference C. To trace the path of a radio signal through the ionosphere D. To draw a waveform on paper 3BD 9.3 D What is a signal tracer normally used for? A. To identify the source of radio transmissions B. To make exact replicas of signals C. To give a visual indication of standing waves on open- wire feed lines D. To identify an inoperative stage in a radio receiver 3BD 10.1 B What is the most effective way to reduce or eliminate audio frequency interference to home entertainment systems? A. Install bypass inductors B. Install bypass capacitors C. Install metal oxide varistors D. Install bypass resistors 3BD 10.2 B What should be done when a properly operating amateur station is the source of interference to a nearby telephone? A. Make internal adjustments to the telephone equipment B. Contact a phone service representative about installing RFI filters C. Nothing can be done to cure the interference D. Ground and shield the local telephone distribution amplifier 3BD 10.3 C What sound is heard from a public address system when audio rectification occurs in response to a nearby single-sideband phone transmission? A. A steady hum that persists while the transmitter's carrier is on the air B. On-and-off humming or clicking C. Distorted speech from the transmitter's signals D. Clearly audible speech from the transmitter's signals 3BD 10.4 C How can the possibility of audio rectification occurring be minimized? A. By using a solid state transmitter B. By using CW emission only C. By ensuring all station equipment is properly grounded D. By using AM emission only 3BD 10.5 A What sound is heard from a public address system when audio rectification occurs in response to a nearby double-sideband phone transmission? A. Audible, possibly distorted speech from the transmitter signals B. On-and-off humming or clicking C. Muffled, distorted speech from the transmitter's signals D. Extremely loud, severely distorted speech from the transmitter's signals 3BD 12.2 D What is the reason for using a speech processor with a single- sideband phone transmitter? A. A properly adjusted speech processor reduces average transmitter power requirements B. A properly adjusted speech processor reduces unwanted noise pickup from the microphone C. A properly adjusted speech processor improves voice frequency fidelity D. A properly adjusted speech processor improves signal intelligibility at the receiver 3BD 12.3 B When a transmitter is 100% modulated, will a speech processor increase the output PEP? A. Yes B. No C. It will decrease the transmitter's peak power output D. It will decrease the transmitter's average power output 3BD 12.4 C Under which band conditions should a speech processor not be used? A. When there is high atmospheric noise on the band B. When the band is crowded C. When the frequency in use is clear D. When the sunspot count is relatively high 3BD 12.5 D What effect can result from using a speech processor with a single-sideband phone transmitter? A. A properly adjusted speech processor reduces average transmitter power requirements B. A properly adjusted speech processor reduces unwanted noise pickup from the microphone C. A properly adjusted speech processor improves voice frequency fidelity D. A properly adjusted speech processor improves signal intelligibility at the receiver 3BD 13.1 A At what point in a coaxial line should an electronic T-R switch be installed? A. Between the transmitter and low-pass filter B. Between the low-pass filter and antenna C. At the antenna feed point D. Right after the low-pass filter 3BD 13.2 C Why is an electronic T-R switch preferable to a mechanical one? A. Greater receiver sensitivity B. Circuit simplicity C. Higher operating speed D. Cleaner output signals 3BD 13.3 D What station accessory facilitates QSK operation? A. Oscilloscope B. Audio CW filter C. Antenna relay D. Electronic TR switch 3BD 14.6 B What is an antenna noise bridge? A. An instrument for measuring the noise figure of an antenna or other electrical circuit B. An instrument for measuring the impedance of an antenna or other electrical circuit C. An instrument for measuring solar flux D. An instrument for tuning out noise in a receiver 3BD 14.7 C How is an antenna noise bridge used? A. It is connected at the antenna feed point, and the noise is read directly B. It is connected between a transmitter and an antenna and tuned for minimum SWR C. It is connected between a receiver and an unknown impedance and tuned for minimum noise D. It is connected between an antenna and a Transmatch and adjusted for minimum SWR 3BD 15.1 B How does the emitted waveform from a properly adjusted single- sideband phone transmitter appear on a monitoring oscilloscope? A. A vertical line B. A waveform that mirrors the input waveform C. A square wave D. Two loops at right angles 3BD 15.2 A What is the best instrument for checking the transmitted signal quality from a CW or single-sideband phone transmitter? A. A monitor oscilloscope B. A field strength meter C. A sidetone monitor D. A diode probe and an audio amplifier 3BD 15.3 B What is a monitoring oscilloscope? A. A device used by the FCC to detect out-of-band signals B. A device used to observe the waveform of a transmitted signal C. A device used to display SSTV signals D. A device used to display signals in a receiver IF stage 3BD 15.4 D How is a monitoring oscilloscope connected in a station in order to check the quality of the transmitted signal? A. Connect the receiver IF output to the vertical-deflection plates of the oscilloscope B. Connect the transmitter audio input to the oscilloscope vertical input C. Connect a receiving antenna directly to the oscilloscope vertical input D. Connect the transmitter output to the vertical-deflection plates of the oscilloscope 3BD 17.2 A What is the most appropriate instrument to use when determining antenna horizontal radiation patterns? A. A field strength meter B. A grid-dip meter C. A wave meter D. A vacuum-tube voltmeter 3BD 17.3 C What is a field-strength meter? A. A device for determining the standing-wave ratio on a transmission line B. A device for checking modulation on the output of a transmitter C. A device for monitoring relative RF output D. A device for increasing the average transmitter output 3BD 17.4 A What is a simple instrument that can be useful for monitoring relative RF output during antenna and transmitter adjustments? A. A field-strength meter B. An antenna noise bridge C. A multimeter D. A Transmatch 3BD 17.5 B When the power output from a transmitter is increased by four times, how should the S-meter reading on a nearby receiver change? A. Decrease by approximately one S-unit B. Increase by approximately one S-unit C. Increase by approximately four S-units D. Decrease by approximately four S-units 3BD 17.6 C By how many times must the power output from a transmitter be increased to raise the S-meter reading on a nearby receiver from S-8 to S-9? A. Approximately 2 times B. Approximately 3 times C. Approximately 4 times D. Approximately 5 times -------------------------------------------------- End of Subelement 3BD.