This. If we are going to have a discussion about this, I really, really hope to at least see some dBm numbers.
From a test right now, picking up my Blackberry 8100 (antenna along the bottom) in roughly the manner I would use to hold it to my ear, I lose about 10 to 15 dBm (from around -66 to -69 to around -79 to -81), which means the received signal power drops by around 10 to 30 times. I don't know if that's particularly good or bad; I've never had problems with dropped calls.
An app that instructs the user to pick up the phone and hold it to his head as he would while talking, records the RSSI over a course of a couple of minutes, then graphs or displays the results might be an interesting weekend project.
You can do it if you've jailbroken. Haven't looked for non-jailbroken stuff.
On my 3GS, I can vary up to 20 dBm depending on how I'm holding it, how I rotate myself and/or the phone, where I'm holding it in relation to my body, etc.
Regardless of the actual numbers, the issue doesn't appear when the gap in the antenna is taped over or it is otherwise insulated (like with a bumper).
That strongly suggests to me that this is something over and above normal loss of signal caused by picking up in a hand.
Sure -- but I've also seen reports that the effect is much more pronounced in areas of spotty coverage (as measured by bars). Perhaps, even though over and above, the degradation is still acceptable with areas of good coverage.
From a test right now, picking up my Blackberry 8100 (antenna along the bottom) in roughly the manner I would use to hold it to my ear, I lose about 10 to 15 dBm (from around -66 to -69 to around -79 to -81), which means the received signal power drops by around 10 to 30 times. I don't know if that's particularly good or bad; I've never had problems with dropped calls.