单项选择题

Which antenna generally has the narrowest first Fresnel zone in both the horizontal and verticalplanes？（）

A.omnidirectional
B.patch
C.Yagi
D.sector
E.parabolic dish

<上一题目录下一题>

热门试题

多项选择题

WhichtwomethodscanbeusedtopreventorreduceRFIfromcolocateddirectionalantennas（）

A.Alternate polarization between colocated antennas
B.Cross-polarize antennas between endpoints
C.Install an RF-shielded box around the antennas
D.Increase the distance between the antennas

单项选择题

Ciscorecommendsadecibelreferencedto1milliwattsignallevelforthecoveragecelledgeatthepredetermineddataratethatisneededtosupporttheVoWLANdeviceandcallcapacityrequirements.WhatisthatsignallevelvalueforCiscoUnifiedWirelessIPPhones7920，7921G，and7925G？（）

A.-65 dBm
B.-67 dBm
C.-69 dBm
D.-70 dBm