CC3000 Hookup Guide
This Tutorial is Retired!
This tutorial covers concepts or technologies that are no longer current. It's still here for you to read and enjoy, but may not be as useful as our newest tutorials.
Shawn Hymel 
Connecting an External Antenna
IMPORTANT: This step is optional! You don't need to add an external antenna to get the CC3000 to work (the chip antenna on the shield and breakout board works well enough). Only do this if you need to add an external antenna.
Both the CC3000 Shield and Breakout Board offer the ability to attach an external antenna. This is a handy feature if you want to route an antenna to the outside of an enclosure or to increase your WiFi gain.
Shield
Desolder the capacitor labeled "Antenna Select."
Rotate the capacitor at a 90° angle so that it is connecting the trace coming out of the CC3000 and the trace going to the U.FL connector.
Attach the RP-SMA to U.FL cable to the U.FL connector. Connect the 2.4GHz antenna (or 2.4GHz large antenna) to the cable.
Note that you can use some Angle Brackets, 4-40 Screws, 4-40 Nuts, and a piece of drilled (or laser-cut) plastic to hold the antenna onto the CC3000 Shield.
Breakout Board
For the CC3000 Breakout Board, you will need to perform the same operation as on the shield to rotate the Antenna Select capacitor by 90°.
You may then connect an antenna to the U.FL connector.