GS3 Android antenna connectivity problem

discription of problem 

I've got a problem with my phone, Samsung GS3 Gt-i9300, in the top notification bar, it says I have service, and it also says that when I slide the notification centre down.

Everytime I try to call someone, or text or use cellular data, it doesnt work, when i try to call someone it gets stuck at "Dialing" and whenever i try to text it gives me an error saying that the message was not sent. my cellular data just doesnt work, like it's not enabled at all.

furthermore, I cant recieve any calls or texts when my phone does this, which is a real pain in the neck, considering I cant use the device what it was intended for.

my current solution is to restart whenever I need to use my phone like a phone, and then it works for about a good 10 minutes (sometimes it works for longer, like an hour or two, and sometimes it only works for a minute) and then goes back to this stage.

background info

My phone is a Belgian or French model, and I live in the netherlands (shouldnt be a problem, since its internationally unlocked).

it shipped with the firmware version 4.0.X

currently its running on 4.1.2

what I've tried so far


when I first got it, it had 4.0.X on it (X= a number i forgot, I think its 1 though), so I tried flashing a leaked version of jellybean on it (4.1), later i updated it to 4.1.2 and the problem still wasnt solved. I had also rooted my phone at this point. 

and recently I unrooted my phone and went to a normal 4.1.2 version, and the problem is still there.

I have also had numerous calls with my provider (T-mobile) and the problem is not on their side either. 

I have also tried other sim cards, and the same problem occurs on those as well. 

And lastly, I have cleaned the sim card slot numerous times, and it didnt help whatsoever.


I have heard of people patching the antenna software...? not sure if this makes sense...

what can I do?

Please tell me if you need more information...



Try baseband switcher (I think that's what it is called) by Team Sonic or such on XDA-Developers?

Edit: I think the keywords you're looking for is Baseband/Modem so you could reconfigure settings for the region.

How exactly did you revert it to stock?

Also, if you type *#1234# in your dialer what does it read?