GSM detection/identification

[Paul Buede]

So, I picked up a tmobile sim, and signed up with them (I have another
week to cancel), and so the phone registers with tmobile.  I am finding
the coverage isn't great in the rural areas I find myself.  When driving
around, if out of reach of tmobile, it will say "registering" as if
there is no sim card.  But, on the little image of the antenna, that
shows how strong my connection is, I still have 2 bars.  Is that a bad
guage of connectivity?  Is it wrong?  Or does that maybe tell me that it
has 2 bars of strength with some sort of other gsm network?  Is there a
way I can query the phone from the cli to have it show me the different
carriers it can sense network for?  I am interested in running a little
cron to pipe all carriers it detects into a file every minute as I drive
around the countryside, so I can see  who i will get the best coverage with.

Thanks