Actualy I haven't seen this phone yet, but as I can see in the repair manual, there is no RF connector for external antenna. So, in that case there is only one posibility to have connected external antenna. You have to connect RF cable from the antenna directly to the phone's PCB, at the point where starts the internal antenna. One sugestion: its beter to solder mini-smd-RF connector instead of soldering the cable directly (to keep mobility)
Don't hesitate to drill that neded small hole on the back panel, atherwise nothing could be done

PS Do Not make any changes for yourself if you haven't enough skills. Better call some friend of you, who has!

i have a nokia 1100 and im always in the basement where i never can get a signal. i was wondering if anyone would have any tips on how to make an external antenna for the phone. what would i need and how would i set it up?