Firstly, thank you for your answer Onno.
About power and polarization subjects you have deleted my doubts.
I have some difficult to understand how radio chains work with antenna on the different mode as 802.11g, 802.11n and 802.11ac.
You mean every protocols, all radio chain and antenna are used. Don't you?
I try to explain my situation in order to give a full view
Inside my suite we have some APs with an extenal antenna that is not the default omni stick. For simplicity I call it "plus antenna".
It's been running a SSID on 802.11g and no high throughput enabled, where the plus antenna is connected to Ant0 of the APs as best internal pratice.
So I suppose the Aruba AP model 204 is working on SISO mode. Is it correct? Does Radio 1 (2.4) work with only Ant0? Or both antennas? If both antennas are used how AP works in this situation? Can I manage it?
If it is an Aruba 304 with 3 antenna, do you know how it behaves?
Thank you for your availability
Regards