I switched from Cingular TDMA to tMobile GSM some months ago.

Before switching, the concept of not having enough signal strength bars was so
foreign to me that I never even thought of it as possible.

Now zero bars are a daily occurrance.   I can't even get a call out from the
first floor of my wood frame house - although the second floor is usually OK.
Today my wife found that her phone wouldn't work inside of a tour bus.

So, the question:  Is there something about tMobile GSM that makes it perform so
poorly inside of structures compred to Cingular TDMA?    A different freq maybe?
I recall somebody in the group observing that 900 & 1900 have different building
penetrations.