Your options are pretty limited. First and foremost, if you don't have adequate AT&T coverage in your area, there is simply nothing that you can do to improve the situation.
That said, the antenna for the iPhone is located on the bottom of the iPhone. You may be able to eke out a little additional signal strength depending on iPhone orientation (don't cover it with your hand).
Some reception is due to interference (building materials, other wireless products in the area). Try moving to a different area within the location you are trying to call from.
Finally, you may want to look into a cell phone booster. Products are not cheap, but do exist to beef up your signal strength.
I have one for HTC 8125, I never used but it looks like a metal coil-like oval shaped thing that is supposed to stick to the back of the phone, the only reason I got was because I found for $3 dollars.
-But I'd imagine that for an iphone-if Apple made it- they would over-price lit like hell probably be like $50 dollars
I like Catherine's avatar.
Anyways, I had great service with Verizon and terrible now with AT&T. If I go to my mom's house I get no service at all with AT&T. I called AT&T a few times about this. They said the more people call and complain about a certain area the more they will take a look and see if they need to improve service in that area. They also did something while I was on the phone with them to resend some kind of new signal to my phone and had me turn my phone off and on several times. It seems to get a little better but still not as good as Verizon.
Another thing that was posted in this forum a few months ago that helps sometimes is if you take your sim card out and put a tiny piece of scotch tape on it. For some reason it picks up a better signal. I tried this and did get an extra bar out of it. You can search the forum here for instructions on how to do this.
Put some scotch tape on the SIM? That is the weirdest thing I have ever heard, who would have ever thought to try that?
-It sucks how the most simplest things are needed to function the most advanced technology
I have 4 or 5 bars and my calls are getting dropped. It's happen 5 times already and 2 times today both with 5 bars, so I wonder why my bars are so high yet my calls are getting dropped. This is even on Wi-Fi in my house which has happen 2 times.