V300 Provider Question

I recently switched my t-mobile V300 over to cingular, hoping that i'd get a better signal around my home, because my brother gets a full signal with his cingular phone.

Everywhere I've gone I've noticed my signal hasn't changed at all/much, is there a reason/solution for this?

Is it the same exact phone, just unlocked? If it is, the problem lies in the phone.

Yes, it's the same phone.

Your phone is missing the 850 band which Cingular uses. http://www.phonescoop.com/phones/phone.php?p=357

Your reception will improve once you get an 850 phone.

I take it there's no way to mod it in there?

It's actually a hardware issue. You can get phones for under $100.00 on ebay(check for 850 band). Don't assume phone has this band if it's listed as tri band. If your really unsure, just buy a quad band phone.