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26.
Which of these propagation behaviors can result in multipath? (Choose all that apply.)
- A.Refraction
- B.Diffraction
- C.Reflection
- D.Scattering
- E.None of the above
- Answer & Explanation
- Report
Answer : [A, B, C, D]
Explanation :
Explanation :
| Multipath is a propagation phenomenon that results in two or more paths of a signal arriving at a receiving antenna at the same time or within nanoseconds of each other. Because of the natural broadening of the waves, the propagation behaviors of reflection, scattering, diffraction, and refraction can all result in multiple paths of the same signal. The propagation behavior of reflection is usually considered to be the main cause of high-multipath environments. |
27.
Which behavior can be described as an RF signal encountering a chain link fence, causing
the signal to bounce into multiple directions?
- A.Diffraction
- B.Scatter
- C.Reflection
- D.Refraction
- E.Multiplexing
- Answer & Explanation
- Report
Answer : [B]
Explanation :
Explanation :
| Scattering, or scatter, is defined as an RF signal reflecting in multiple directions when encountering an uneven surface. |
28.
Which 802.11 radio technologies are most impacted by the destructive effects of multipath?
(Choose all that apply.)
- A.802.11a
- B.802.11b
- C.802.11g
- D.802.11n
- E.802.11i
- Answer & Explanation
- Report
Answer : [A, B, C]
Explanation :
Explanation :
| High multipath environments can have a destructive impact on legacy 802.11a/b/g radio transmissions. Multipath has a constructive effect with 802.11n and 802.11ac transmissions that utilize MIMO antenna diversity and maximum ratio combining (MRC) signal processing techniques. Multipath does not affect the security mechanisms defined by 802.11i. |
29.
Which of the following can cause refraction of an RF signal traveling through it? (Choose
all that apply.)
- A.Shift in air temperature
- B.Change in air pressure
- C.Humidity
- D.Smog
- E.Wind
- F.Lightning
- Answer & Explanation
- Report
Answer : [A, B, C, D]
Explanation :
Explanation :
| Wi-Fi Protected Setup was designed with SOHO users in mind. Enterprise organizations use IEEE 802.11i, WPA, and WPA2 certifi cations. The FCC is the local regulatory authority responsible for frequency regulation in the United States. |
30.
Which of the following statements are true about free space path loss? (Choose all that
apply.)
- A.RF signals will attenuate as they travel, despite the lack of attenuation caused by obstructions.
- B.Path loss occurs at a constant linear rate.
- C.Attenuation is caused by obstructions.
- D.Path loss occurs at a logarithmic rate.
- Answer & Explanation
- Report
Answer : [A, D]
Explanation :
Explanation :
| Because of the natural broadening of the wave front, electromagnetic signals lose amplitude as they travel away from the transmitter. The rate of free space path loss is logarithmic and not linear. Attenuation of RF signals as they pass through different mediums does occur but is not a function of FSPL. |
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