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
The Question Pool
[edit | edit source]Question 1
[edit | edit source]- 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
[edit | edit source]- 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
[edit | edit source]- 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
[edit | edit source]- 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
[edit | edit source]- 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
[edit | edit source]- 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
[edit | edit source]- 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
[edit | edit source]- 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
[edit | edit source]- 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
[edit | edit source]- 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
[edit | edit source]- 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.