QuickerTek also includes a software CD that you can use to measure your wireless system performance before and after the installation. The retail price is US$130, and the 5 Dbi is available now.

You can get gain in the 20 dBi range like that, this is easily capable of transmitting 802.11b (b is better at range than g is) over ten miles to a similar antenna and half a mile to a mile to an ...

which, dbi or watts, helps more for a)range b)signal strength and how many dbi and watts is a typical wireless usb stick with no external aerial?