I have a WAP11 accesspoint, and I was told that the two antennas are only used to alternate between... eg: if you have one outside, and one inside, the one outside will get signal, then the one inside, then the one outside etc etc.... they dont happen at same time... i think i explained it right

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If you look in the advanced options of the WAP11 (version 2 - web based), you will see that you can choose which antenna to use... (1st, 2nd or both)...
this is why they provide this, so you can only use one if u want (for example for an outdoor antenna)...
hope this answered your question about the two antennas