TUAW posted a video that the Phone 4 antenna issue is not simply a result of Apple's miscalculation of how many bars are being displayed

You wanted a demonstration? You got a demonstration; we've put together a video to show how the iPhone 4 antenna issue is not simply a result of Apple's miscalculation of how many bars are being displayed. Our own Erica Sadun wrote an iPhone app (at the suggestion of Engadget's Nilay Patel) to display the raw signal strength, the number of bars, and what Apple calls the graded signal strength. Erica's tests (see video above) show that the "Kung Fu grip of doom" results in the signal strength dropping to almost zero. According to Erica, removing her hand from the antenna gap brings the signal strength back to normal.

Video evidence of the iPhone 4 death grip -- this time with real numbers