Hi there, just wondering is there a pinout for connecting an optional external aerial to the unit at all?
If you look at the shield you will see a set of 5 holes right near the PC antenna:
Looks like a standard SMA RF connector of some kind should solder right in there.
probably you could modify the shield in order to obtain this http://www.exp-tech.de/Mainboards/Arduino/Arduino-GSM-Shield-antenna-connector.html