When you use WBC, you lost 3db.
Example:
site with 2 antenna=> bypass (222 max) if you want a 3nd, you must use WBC.
on antenna 1 => tx1 rx1 div2
on antenna 2 => tx2 rx2 div1
site with 2 antenna => WBC (444 max)
on antenna 1 => tx1, tx2, rx1, rx2, div3, div4
on antenna 2 => tx3, tx4, rx3, rx4, div1, div2