wlc 2504 external antenna gain

[michelepenna]

Hello,

i write to ask a question related to a WLC 2504:

we have several 2602 access points with external antennas, and some 1552 aps, i wonder if i have to set explicitly the Antenna Gain parameter in the configuration, or if i can leave the default value of 0 dBi.

Thanks

Michele

[mhnedirli]

hi, 

as i know you couldnt change the antenna gain, it is depend your region settings

[michelepenna]

Hi,

in ap with external antennas there is the option to change this parameter, default value is 0 x 0.5 dBi. (There is also the option to disable some antennas.)

I have antennas with gain of 2 dBi, so i'd have to set the parameter to 4, my question is if there are real advantages in doing this.

Thanks

[Clemens Gruber]

Yes, I think so.

I have one customer with a AIR-CAP2602E using the omni-directional 4dBi dual-band antenna (AIR-ANT2544V4M-R) and setting the parameter to 8x0.5dBi did help increase the signal-strength for 802.11g/n and improved the coverage in our environment.

I don't think APs with external antenna ports can detect what antenna was connected, or am I mistaken? I always manually set this parameter to the recommended gain value. It's just a little difficult to find, if you are using the GUI. It's in the Configure (or Details?) submenu of the AP list. You have to do this both for 802.11b/g/n and 802.11a/n.

[Venkatesh Attuluri]

Anteenna gain : ability to direct or focus radio energy over a region of space. High-gain antennas have a more focused radiation pattern in a specific direction

http://www.cisco.com/c/en/us/td/docs/wireless/access_point/12-3_2_JA/configuration/guide/i1232sc/s32chan.html

[Saurav Lodh]

below is one guideline

In the Antenna Gain text box, enter a number to specify an external antenna’s ability to direct or focus radio energy over a region of space. High-gain antennas have a more focused radiation pattern in a specific direction. The antenna gain is measured in 0.5 dBi units, and the default value is 7 times 0.5 dBi, or 3.5 dBi. If you have a high-gain antenna, enter a value that is twice the actual dBi value (see Cisco Aironet Antenna Reference Guide for antenna dBi values). Otherwise, enter 0. For example, if your antenna has a 4.4-dBi gain, multiply the 4.4 dBi by 2 to get 8.8 and then round down to enter only the whole number (8). The Cisco WLC reduces the actual equivalent isotropic radiated power (EIRP) to make sure that the antenna does not violate your country’s regulations.

[michelepenna]

Thanks for the reply.

My question is more related to the real need to change this value.

I mean, i have 2602 ap with 4 dipole antennas each (2 dBi for 2.4 GHz), there's a real difference in the performances having the gain set to real value instead of leaving it to the default 0 value?