I asked this question in our Answers beta, and I got these responses for you. Let us know if any of them fix your problem!

From tlcgraham:

Sounds like a loose connection for the antenna.

From wtylko:

Every time you loose service a much faster way to get service is to turn AirPlane mode on and off. Also have you updated your iphone to the latest software? If you haven't you should do it. And if all this does not work try restoring your iPhone an and get it swapped out at the genius bar. But don't tell them you dropped it. They have no way to find out! Also un-jail break you're phone before you take it there.

From bmalam:

Hate to state the obvious, but have you tried a reboot?

[quote|Kyle Wiens]I asked this question in our [link|/Beta|Answers beta], and I got these responses for you. Let us know if any of them fix your problem! From tlcgraham: Sounds like a loose connection for the antenna. From wtylko: Every time you loose service a much faster way to get service is to turn AirPlane mode on and off. Also have you updated your iphone to the latest software? If you haven't you should do it. And if all this does not work try restoring your iPhone an and get it swapped out at the genius bar. But don't tell them you dropped it. They have no way to find out! Also un-jail break you're phone before you take it there. From bmalam: Hate to state the obvious, but have you tried a reboot?[/quote]

All my stuffs up to date all the sofeware but a lose antenna connection was my guess also and yes i knew about the airplain trick its a must i think for iphone users. If, the antenna connection is loose how should i go about fixing it?. if its broke can i buy another internal antenna?

[quote|steven]All my stuffs up to date all the sofeware but a lose antenna connection was my guess also and yes i knew about the airplain trick its a must i think for iphone users. If, the antenna connection is loose how should i go about fixing it?. if its broke can i buy another internal antenna?[/quote]

you could probably use a guide here at ifixit to get into it and pick up an antenna or tighten the one you have

[quote|Skippy722]you could probably use a guide here at ifixit to get into it and pick up an antenna or tighten the one you have[/quote]

i didnt see any antenna parts for the 3g all i seen was a cover for it.soes this sight carry them and if not what sites would you suggest?

[quote|steven]i didnt see any antenna parts for the 3g all i seen was a cover for it.soes this sight carry them and if not what sites would you suggest?[/quote]

is the iPhone still under some sort of warrenty? if it is, do what was suggested above and unjail break it, and take it into an AT&T store

wait, I didn't think that by jail breaking an iPhone you can use a whole diff network, I learn something new everyday

[quote|Skippy722]is the iPhone still under some sort of warrenty? if it is, do what was suggested above and unjail break it, and take it into an AT&T store wait, I didn't think that by jail breaking an iPhone you can use a whole diff network, I learn something new everyday[/quote]

Ok my problem is that the airplane mode is not working for me. My phone keeps telling me to restore to default settings. I did that and still now service.. After calling AT&T they sugguested that maybe I need a new sim card... Do you think that is possible..Pls help this is a replacement phone.. due to the fact the phone I purchased kept turning off and on

[quote|blackberri09]Ok my problem is that the airplane mode is not working for me. My phone keeps telling me to restore to default settings. I did that and still now service.. After calling AT&T they sugguested that maybe I need a new sim card... Do you think that is possible..Pls help this is a replacement phone.. due to the fact the phone I purchased kept turning off and on[/quote]