Unlock Signal Issue

[Taylro18753]

I have unlocked my blackberry 8900 from Tmobile to use with AT&T. I have spoken with AT&T numerous times about issues that kept popping up (Browser, Voicemail) everything finally works however I've noticed I get spotty coverage at best and my phone frequently switches to SOS. This is very frustrating.Any solutions?

Sidenote
Do I have to do anything to my APN setting they still say Tmobile(I'm a newb obviously)

[MysticMeg]

You could try cleaning your sim card and if this still doesn't prevent the problem from stopping then back up your phone and reflash it maybe this may prevent the spotty coverage from re-occurring.

[freethisberrydotcom]

Place it in 2G/GSM in Manage Connections - Mobile Network Options.