FCC Technician Class Exam Study Guide - 2014-2018/Subelement T3 Group A

Radio wave characteristics: how a radio signal travels; fading; multipath; wavelength vs. penetration; antenna orientation

Question 1

 * What should you do if another operator reports that your station's 2 meter signals were strong just a moment ago, but now they are weak or distorted?
 * A. Change the batteries in your radio to a different type
 * B. Turn on the CTCSS tone
 * C. Ask the other operator to adjust his squelch control
 * D. Try moving a few feet or changing the direction of your antenna if possible, as reflections may be causing multi-path distortion

The correct answer is D.

Question 2

 * Why are UHF signals often more effective from inside buildings than VHF signals?
 * A. VHF signals lose power faster over distance
 * B. The shorter wavelength allows them to more easily penetrate the structure of buildings
 * C. This is incorrect; VHF works better than UHF inside buildings
 * D. UHF antennas are more efficient than VHF antennas

The correct answer is B.

Question 3

 * What antenna polarization is normally used for long-distance weak-signal CW and SSB contacts using the VHF and UHF bands?
 * A. Right-hand circular
 * B. Left-hand circular
 * C. Horizontal
 * D. Vertical

The correct answer is C.

Question 4

 * What can happen if the antennas at opposite ends of a VHF or UHF line of sight radio link are not using the same polarization?
 * A. The modulation sidebands might become inverted
 * B. Signals could be significantly weaker
 * C. Signals have an echo effect on voices
 * D. Nothing significant will happen

The correct answer is B.

Question 5

 * When using a directional antenna, how might your station be able to access a distant repeater if buildings or obstructions are blocking the direct line of sight path?
 * A. Change from vertical to horizontal polarization
 * B. Try to find a path that reflects signals to the repeater
 * C. Try the long path
 * D. Increase the antenna SWR

The correct answer is B.

Question 6

 * What term is commonly used to describe the rapid fluttering sound sometimes heard from mobile stations that are moving while transmitting?
 * A. Flip-flopping
 * B. Picket fencing
 * C. Frequency shifting
 * D. Pulsing

The correct answer is B.

Question 7

 * What type of wave carries radio signals between transmitting and receiving stations?
 * A. Electromagnetic
 * B. Electrostatic
 * C. Surface acoustic
 * D. Magnetostrictive

The correct answer is A.

Question 8

 * Which of the following is a likely cause of irregular fading of signals received by ionospheric reflection?
 * A. Frequency shift due to Faraday rotation
 * B. Interference from thunderstorms
 * C. Random combining of signals arriving via different paths
 * D. Intermodulation distortion

The correct answer is C.

Question 9

 * Which of the following results from the fact that skip signals refracted from the ionosphere are elliptically polarized?
 * A. Digital modes are unusable
 * B. Either vertically or horizontally polarized antennas may be used for transmission or reception
 * C. FM voice is unusable
 * D. Both the transmitting and receiving antennas must be of the same polarization

The correct answer is B.

Question 10

 * What may occur if data signals propagate over multiple paths?
 * A. Transmission rates can be increased by a factor equal to the number of separate paths observed
 * B. Transmission rates must be decreased by a factor equal to the number of separate paths observed
 * C. No significant changes will occur if the signals are transmitting using FM
 * D. Error rates are likely to increase

The correct answer is D.

Question 11

 * Which part of the atmosphere enables the propagation of radio signals around the world?
 * A. The stratosphere
 * B. The troposphere
 * C. The ionosphere
 * D. The magnetosphere

The correct answer is C.