FCC Technician Class Exam Study Guide - 2014-2018/Subelement T7 Group B

Common transmitter and receiver problems: symptoms of overload and overdrive; distortion; causes of interference; interference and consumer electronics; part 15 devices; over and under modulation; RF feedback; off frequency signals; fading and noise; problems with digital communications interfaces

Question 1

 * What can you do if you are told your FM handheld or mobile transceiver is over-deviating?
 * A. Talk louder into the microphone
 * B. Let the transceiver cool off
 * C. Change to a higher power level
 * D. Talk farther away from the microphone

The correct answer is D.

Question 2

 * What would cause a broadcast AM or FM radio to receive an amateur radio transmission unintentionally?
 * A. The receiver is unable to reject strong signals outside the AM or FM band
 * B. The microphone gain of the transmitter is turned up too high
 * C. The audio amplifier of the transmitter is overloaded
 * D. The deviation of an FM transmitter is set too low

The correct answer is A.

Question 3

 * Which of the following may be a cause of radio frequency interference?
 * A. Fundamental overload
 * B. Harmonics
 * C. Spurious emissions
 * D. All of these choices are correct

The correct answer is D.

Question 4

 * Which of the following is a way to reduce or eliminate interference by an amateur transmitter to a nearby telephone?
 * A. Put a filter on the amateur transmitter
 * B. Reduce the microphone gain
 * C. Reduce the SWR on the transmitter transmission line
 * D. Put a RF filter on the telephone

The correct answer is D.

Question 5

 * How can overload of a non-amateur radio or TV receiver by an amateur signal be reduced or eliminated?
 * A. Block the amateur signal with a filter at the antenna input of the affected receiver
 * B. Block the interfering signal with a filter on the amateur transmitter
 * C. Switch the transmitter from FM to SSB
 * D. Switch the transmitter to a narrow-band mode

The correct answer is A.

Question 6

 * Which of the following actions should you take if a neighbor tells you that your station’s transmissions are interfering with their radio or TV reception?
 * A. Make sure that your station is functioning properly and that it does not cause interference to your own radio or television when it is tuned to the same channel
 * B. Immediately turn off your transmitter and contact the nearest FCC office for assistance
 * C. Tell them that your license gives you the right to transmit and nothing can be done to reduce the interference
 * D. Install a harmonic doubler on the output of your transmitter and tune it until the interference is eliminated

The correct answer is A.

Question 7

 * Which of the following may be useful in correcting a radio frequency interference problem?
 * A. Snap-on ferrite chokes
 * B. Low-pass and high-pass filters
 * C. Band-reject and band-pass filters
 * D. All of these choices are correct

The correct answer is D.

Question 8

 * What should you do if something in a neighbor’s home is causing harmful interference to your amateur station?
 * A. Work with your neighbor to identify the offending device
 * B. Politely inform your neighbor about the rules that prohibit the use of devices which cause interference
 * C. Check your station and make sure it meets the standards of good amateur practice
 * D. All of these choices are correct

The correct answer is D.

Question 9

 * What is a Part 15 device?
 * A. An unlicensed device that may emit low powered radio signals on frequencies used by a licensed service
 * B. A type of amateur radio that can legally be used in the citizen's band
 * C. A device for long distance communications using special codes sanctioned by the International Amateur Radio Union
 * D. A type of test set used to determine whether a transmitter is in compliance with FCC regulation 91.15

The correct answer is A

Question 10

 * What might be the problem if you receive a report that your audio signal through the repeater is distorted or unintelligible?
 * A. Your transmitter may be slightly off frequency
 * B. Your batteries may be running low
 * C. You could be in a bad location
 * D. All of these choices are correct

The correct answer is D.

Question 11

 * What is a symptom of RF feedback in a transmitter or transceiver?
 * A. Excessive SWR at the antenna connection
 * B. The transmitter will not stay on the desired frequency
 * C. Reports of garbled, distorted, or unintelligible transmissions
 * D. Frequent blowing of power supply fuses

The correct answer is C.

Question 12

 * What might be the first step to resolve cable TV interference from your ham radio transmission?
 * A. Add a low pass filter to the TV antenna input
 * B. Add a high pass filter to the TV antenna input
 * C. Add a preamplifier to the TV antenna input
 * D. Be sure all TV coaxial connectors are installed properly

The correct answer is D.