sfx2000
Part of the Furniture
While antenna does not resolve 2.4 GHz issues, it's still really key for any well performing wireless. No matter it is Wi-Fi or cellular.
AP antenna bi-directional gain is the only way to enhance client uplink radio link budget, if clients are what they are (phones etc). Proper antenna (directional, vertical, horizontal gain) allows focusing AP transmitted energy more to target area and helps to reduce utilization elsewhere. Directionality helps also to reduce impact of interference from unnecessary directions (for example from upstairs and downstairs). The more dense environment, the more it has impact. It's also important to remember that antenna gain does not end at 0 dB. Many small end user terminal antennas actually attenuate signal both ways. Antenna may have omnidirectional nature and effective average gain may be - 3dB due to implementation losses.
A lot of people found these two blogs on antennas useful.
Antenna design is critical, without a doubt - but at the same time, well designed antennas can be done internal or external - but again, belief bias by SOHO consumers equate big honking di-poles, and lots of them, as being better...
A well designed internal array can, and often does, perform better...