cell phone oddity

The signal I get on this tracfone (with TF64SIMC4 SIM card, indicating an AT&T network) has always been really shitty in my house.  Usually I can't get a signal at all.

I've discovered, however, that I can keep a low signal (one to two "bars") at my desk if I turn the phone on where it has a better signal (four to five "bars") and manage to not lose signal on the way back home.

The only problem with that is, I don't really know where I have signal.  It seems completely random.  Sometimes I have five "bars" in CAINE house, other times zero.  I got five on the front porch of a friend's place a few days ago, but immediately upon walking in it dropped to three.

I think I need to contact their technical support and see if I can get them to send me a T-Mobile SIM card (a TF64SIMT5).  I know nobody on the AT&T network, but I know a couple people on T-Mobile including one very heavy G1 smartphone user, and they don't have reception problems.  Man, those Android phones are sexy.

I hate this "bars" system of measurement for signal strength.  Obviously more is better, and they needed something to represent the signal strength to simplify it so non-technical idiotspeople can understand, but...  how many dB (decibels) is a "bar"?  Does it scale linearly (i.e. is one "bar" half of two "bars", and is two half of four, is one plus two three, etc.)?  What's my SNR (signal to noise ratio)?  Do "bars" take SNR into account?  I guess if you know me you could probably have figured this out about me, but I hate arbitrary and meaningless things.  Some arbitrary things are arbitrary but unique (like the row id of a record in a database), and thus meaningful.  Other things (like these "bars") just serve to hide the actual measurement system and are better done away with.