Have you noticed that:

Chinese 2HP motors are the size of American 3/4 HP motors, but not as powerful?

Chinese size 11 shoes hurt on American size 10 1/2 feet?

Chinese XXL shirts fit way too tight on an XXL guy?

Regrettably, Chinese decibels seem to be larger than American and European decibels. Maybe Taiwanese decibels are OK, but I doubt that mainland decibels are kosher.

Reason I say this; there are omni antennas on eBay that claim to have 22 dBi gain, when no one else can get more than 18 out of an omni. Either different laws of physics apply, or they use incompatible decibels. Maybe metric?

These are honest people; technically and business-dealings wise:

2.4 GHz 15 dBi Omnidirectional Antenna

Note that this monsrosity is only 3 db hotter than this 12 dBi omni:

12dbi Omni Directional High Gain Wifi Network Antenna - eBay (item 300217491442 end time Apr-25-08 14:21:31 PDT)

Which bears a remarkable resemblance to this 9 dBi omni:

9 dBi Antenna WiFi Wireless LAN Omni Directional 802.11 - eBay (item 370043891217 end time Apr-25-08 08:52:29 PDT)

I would go with the Hyperlinktech. You would need a pigtail to connect to the AP:

195 Series Radio Pigtails