Hi Lorenzo,
You probably want to set the Left or Right Primary (I'm not on site right now so I can't see or remember) and take the setting out of Diversity;
Use the antenna configuration interface command to configure the radio receive or transmit antenna settings. Use the no form of this command to reset the receive antenna to defaults.
[no] antenna {receive | transmit} {diversity | left | right}
Syntax Description
receive
Specifies the antenna that the access uses to receive radio signals
transmit
Specifies the antenna that the access uses to transmit radio signals
diversity
Specifies the antenna with the best signal
left
Specifies the left antenna
right
Specifies the right antenna
Defaults
The default antenna configuration is diversity
Examples
This example shows how to specify the right receive antenna option:
AP(config-if)# antenna receive right
This example shows how to set the receive antenna option to defaults:
AP(config-if)# no antenna receive
From this doc;
http://www.cisco.com/en/US/products/hw/wireless/ps430/products_command_reference_chapter09186a0080147d8b.html#2448409
Hope this helps!
Rob
