RF radiation pattern is described by E - plane (elevation chart) and H - plane (azimuth chart) .
Expressed in dB .
Each antenna design produces different RF radiation patterns .
Polarization describes the orientation of the electric field.
It can be linear or circular.
The magnetic field is on the right of the electric field.
Wireless antennae can use any polarization, but consistency is required. Vertical polarization is common.
90 degrees perpendicular to the electric field
Some wireless technologies use diversity to choose, on a per - client basis, which antenna to use to receive and which to answer. Antennae should be the same type and in the same area.
“Rubber Duck” 2.14 dBi Dipole
AIR ANT 1728, Ceiling Mount Omni 5.2 dBi
AIR ANT 2506/24120
5.2 dBi Omni Mast Mount 12 dBi Omni Mast Mount
Dual Patch Omnidirectional
5.2 dBi, Pillar Mount
8.5 dBi Patch, Wall Mount
13.5 dBi Yagi Ude Butterfly Effect, Polarization
21 dBi Parabolic Dish
Cables and Connectors “ RP-TNC” connector is used on most Cisco APs. “ N” connector is used on the 1500 Mesh and 1400 Bridge. “ RP-SMA” connector is used on some Linksys products. “ SMA” connector is used on “ pig-tail” type cable assemblies.
An attenuator would be positioned in the same way as the amplifier, but it would not require a power supply.
Attenuators and Amplifiers
Model to Insert Between Antenna and Cable
Lightening Arrestors (Cont.)
Ethernet Lightening Arrestor
Splitters divide the signal between two antennae, but considerably reduce range: a 21 dBi dish loses 4 dBi. Its range drops from 33 to 21 km on each side.
Each antenna radiates in a unique way.
Wireless uses vertical polarization.
Some APs use diversity to offer better resistance to multipath issues.
Antennae can be directional or omnidirectional.
Omnidirectional antennae radiate 360 degrees in the H-plane.
Directional antennae focus their beam more or less depending on models.
Connectors are usually specific to a vendor.
Attenuators and amplifiers can be added to change the power transmitted to the antenna.
Lightening arrestors can mitigate the impact of surrounding lightening strikes on the AP and the network.
Splitters can be used to split the signal of one AP to two antennae.