Questions and CORRECT Answers
Q. what word describes the bending of an RF signal as it passes through a medium of a varying
density from that of free space - CORRECT ANSWER - Refraction
Q. What can cause an excessively high VSWR (voltage standing wave ratio)in a WLAN RF
transmission line? - CORRECT ANSWER - An impedance mismatch in the RF cables and
connectors
Q. What factors influence the distance that an RF signal can be effectively received? -
CORRECT ANSWER - *Receiving station's radio sensitivity
*Free Space Path Loss
*Transmitting station's output power
Q. As an RF wave propagates through space, the wave front experiences natural expansion that
reduces its signal strength in an area. what term describes the rate at which this expansion
happens? - CORRECT ANSWER - Inverse square law
Q. Return Loss is the decrease of forward energy in a system when some of the power is being
reflected back toward the transmitter. - CORRECT ANSWER - Am impedance mismatch
between components in the RF system
Q. What factors are taken into account when calculating the link budget of a point-to-point
outdoor WLAN bridge link? - CORRECT ANSWER - * operating frequency
* transmit antenna gain
* transmit power
Q. A WLAN transmitter that emits a 200mW signal is connected to a cable with 3dB loss. If the
cable is connected to and antenna with a 10dBi gain, what is the EIRP at the antenna element? -
CORRECT ANSWER - 30dBm
,Q. In a long-distance RF link, what statement about Fade Margin is true? - CORRECT
ANSWER - Fade Margin is an additional pad of signal strength designed into the RF
system to compensate for unpredictable signal fade.
Q. Which unit of measurement is an absolute unit that is used to quantify power levels on a linear
scale? - CORRECT ANSWER - dBm
Q. An 802.11 WLAN transmitter that emits a 50mW signal is connected to a cable with 3dB of
loss. The cable is connected to an antenna with 16 dBi of gain
What is the EIRP power output? - CORRECT ANSWER - 1000mW
Q. What is always required to establish a high quality 2.4GHz RF link at a distance of 3 miles
(5kilometers)? - CORRECT ANSWER - A Fresnel Zone that is at least 60% clear of
obstructions
Q. What phrase defines Equivalent Isotropic Radiated Power (EIRP)? - CORRECT
ANSWER - The highest RF signal strength that is transmitted from a given antenna
Q. What term describes the effect of increasing the intensity of an RF wave with an antenna by
focusing the energy in a specific direction? - CORRECT ANSWER - Passive Gain
Q. Which antenna types are commonly used by indoor Wi-Fi devices in a MIMO diversity
implementation? - CORRECT ANSWER - * Dipole
* Patch
Q. When using WMM Power Save operation, a wireless client device
_______________________________. - CORRECT ANSWER - Alternates between
awake and dozing, depending on its need to transmit and receive information
, Q. When replacing the antenna of a WLAN device with a similar antenna type that has a higher
passive gain, what antenna characteristic will decrease? - CORRECT ANSWER -
Beamwidth
Q. What statements about the beamwidth of an RF antenna are true? - CORRECT
ANSWER - * Horizontal and vertical beamwidth are calculated at the points in which the
main lobe decreases power by 3dB.
* Horizontal beamwidth is displayed (in degrees) on the antennas's Azimuth Chart.
Q. What HT technology requires MIMO support on both the transmitter and receiver? -
CORRECT ANSWER - Spatial multiplexing
Q. ABC Company has just purchased a 6 dBi patch antenna. After performing some tests with
the 6 dBi antenna, they have concluded that more antenna gain is needed to cover their outdoor
courtyard. When choosing an antenna with higher gain, what other antenna characteristic will
also
always change? - CORRECT ANSWER - Beamwidth
Q. AP-1 is a 3x3:2 AP. STA-3 is a 3x3:3 client. What is the maximum number of spatial streams
that can be used for a downlink HT-OFDM transmission from AP-1 to STA-3? - CORRECT
ANSWER - Two spatial streams, because the definition of the AP indicates that it is
capable of only two spatial streams.
Q. You are implementing a VHT-capable AP. Which one of the following channels is available in
the 802.11ac amendment to the 802.11-2012 standard, which was not available in the standard
before this amendment? - CORRECT ANSWER - 144
Q. You are selecting antennas for a WLAN operating in the 5 GHz frequency band. What
specifications should be evaluated for an antenna before it is implemented in this WLAN
system? - CORRECT ANSWER - * Impedance in Ohms
* Elevation Beamwidth
*Operating Frequencies