Planning to add a 5GHz 802.11A module to the existing AIR-AP1231G-A-K9. Among other issues - optimal configuration, separation of networks, etc. - I have one pure hardware question:
What is the optimal antenna for a small office - no concrete walls or heavy metal structures?
Cisco antenna guide - http://www.cisco.com/en/US/products/hw/wireless/ps469/products_data_sheet09186a008008883b.html - lists two potential choices:
1. 9dBi Patch/5dBi omnidirectional integrated, which is built in into RM21 5GHz Radio Module (AIR-RM21A-A-K9)
2. RM22 module that comes with no antennas (AIR-RM22A-A-K9), but with two RP-TNC (reverse polarity-threaded naval connector) connectors. These, in turn can accomodate a number of antenna modules, such as AIR-ANT5135D-R dipoles, AIR-ANT5145V-R diversity omnidirectional, and a few others.
I am leaning towards the integrated one - omnidirectional, 5dBi seems to be right, price, and no need to install any additional parts, but I would be very interested in getting peoples' opinions on pros and cons, etc.