Would be nice if someone intentionally held the phone making contact with only one antenna, and then hold normally to see if there is in fact any issue.
I am also seeing this (for the first time actually) on my 3G as well. 4 bars if on the table, 3 if held (and 10+ seconds go by). Just signal attenuation through the body? (edit: am implying the signal passing through the hand is degraded a bit as a result)
In other words, is the external ip4 frame just a red herring and there is some other culprit at work.
WOW! Dude , you are on to something! Try this with your 3GS, it does the exact same thing, at least mine does, very interesting.........