In a Penetration test after receiving the PSK of a WPA2 WLAN it's possible to decrypt the wireless traffic using
airdecap-ng for example. This works well as long as one recorded the associated four-way-handshake of every connection. I prefer this method because it's purely passive and as such it's not detectable on a network level.
The downside of this is that as a passive part I can't tell the accesspoint or the client to resend traffic I did not receive or did receive in a corrupted way. This means that I have to assure a good reception quality in the first place. We are talking about one single accesspoint here. Which kind of Antenna is the most appropriate for ths situation? What are the influence facors I have to pay attention to?