When you need to specify used antenna ports on external antenna WiNG access point, always make sure which RADIO and PORT will be used.
On external antenna APs there are marks used to specify antenna port - it can be number or a letter
On external AP8533 use :
for 2 x 2 you need to use port A and B
for 3x3 A, B, C.
for 2x2 it’s A, B
When choosing/selecting the antenna, it all starts from port - 0
In GUI you can navigate to Configuration -> Profile AP -> Interface -> Radios -> Radio X -> Radio Settings -> Antenna Mode
Using CLI you can set this similar way
1x1 Use only antenna A to receive and transmit
1xALL Transmit on antenna A, receive on all antennas
2x2 Use antenna A and C for both transmit and receive
3x3 Use antenna A, B and C for both transmit and receive
default Use default antenna setting
There are different modes and not all modes are applicable to all SKUs.
For more details, please visit AP installation guides