Changes

[[File:Different gain antennas.jpg|400px]]

[[File:Different gain antennas.jpg|400px]]

* '''Antenna directivity'''. Directional antennas radiate energy in one (or some) direction more effectively than others. Usually directional antenna has main lobe and several minor lobes. Omnidirectional antennas have circular radiation pattern in a given plane and a directional pattern in any orthogonal plane. Omnidirectional antennas widely used in most routers. See omnidirectional and directional antennas examples with their radiation pattern below:

* '''Antenna directivity'''. Directional antennas radiate energy in one (or some) direction more effectively than others. Usually directional antenna has main lobe and several minor lobes. Omnidirectional antennas have circular radiation pattern in a given plane and a directional pattern in any orthogonal plane. Omnidirectional antennas widely used in most routers. See omnidirectional and directional antennas examples with their radiation pattern below:

[[File:Omnidirectional antenna pic.png]][[File:Omnidirectional antenna.gif]]

[[File:Omnidirectional antenna pic.png]][[File:Omnidirectional antenna.gif]]

'''Directional antenna (18dBi)'''

'''Directional antenna (18dBi)'''

[[File:Directional antenna pic.jpg|280px]][[File:Directional antenna vertical horizontal.jpg]]

[[File:Directional antenna pic.jpg|280px]][[File:Directional antenna vertical horizontal.jpg]]

* '''VSWR (voltage standing wave ratio)''' is a function of the reflection coefficient Γ, that describes power reflected from the antenna. The smaller the VSWR is, the more power is delivered to antenna. Minimum VSWR is 1, that means that no power is reflected from the antenna (ideal case). We recommend use Wi-Fi antennas with VSWR≤1.5 and 3G/LTE with VSWR≤2.5.

* '''VSWR (voltage standing wave ratio)''' is a function of the reflection coefficient Γ, that describes power reflected from the antenna. The smaller the VSWR is, the more power is delivered to antenna. Minimum VSWR is 1, that means that no power is reflected from the antenna (ideal case). We recommend use Wi-Fi antennas with VSWR≤1.5 and 3G/LTE with VSWR≤2.5.

* '''Cable (insertion) losses''' must be taken into account when using antennas with long cables. It is a measure of the amount of energy that is absorbed by transmission line (cable) as signal travels down and it is measured in decibels (dB). In general, a smaller diameter cable has more loss than larger diameter cable. For a specific cable type (different cable types have different losses), the longer the cable length the greater the amount of energy it absorbs. Also, losses depend on frequency – the higher the frequency the greater the loss.

* '''Cable (insertion) losses''' must be taken into account when using antennas with long cables. It is a measure of the amount of energy that is absorbed by transmission line (cable) as signal travels down and it is measured in decibels (dB). In general, a smaller diameter cable has more loss than larger diameter cable. For a specific cable type (different cable types have different losses), the longer the cable length the greater the amount of energy it absorbs. Also, losses depend on frequency – the higher the frequency the greater the loss.