QuickerTek has announced that their second generation, higher gain 5dBi Tri-Band Antenna upgrade kit was tested with the newly released Apple 802.11n Extreme Base Station MD031LL/A model A1408.
The folks at QuickerTek say their in-house testing showed up to three times better signal strength then that of the built-in antennas on the Base Station. The 5dBi Tri-Band Antenna Do It Yourself kit can be ordered from their website (http://macte.ch/pnIo7).
The do-it-yourself kit is US$129.99. To have QuickerTek install the antenna for you costs $179.99. Or you can order an already-modified AirPort Extreme Base Station for $349.95. Like most QuickerTek products, the 5dBi Tri-Band Antenna kit has a one year parts and labor warranty.