Non-Scientific Evidence for Signal Loss Issue

Question

I just did a test with my phone. I started a speed test to assure some steady data flow, and then put the phone next to a PC speaker to create the interference noise through the speakers. It came through loud and clear.
I touched the spot in question on the phone (lower left corner, black strip), and the sound stopped, and it coincided with a drop in my speed test. I repeated this a few times, and repeatedly moved my finger to and from the problem spot, and each time I would do that, the sound coming through the PC speaker would stop.
This, to me, shows that the hand is in fact blocking the signal to the device, causing the signal attenuation, and that it is more than just bars being misreported.

Answer 1

The ratio of dBm to power (watts) is logarithmic, which means as dBm decreases the power of the signal decreases exponentially. You can get wattage from dBm by this formula:
P = 10^((x - 30)/10) where x is in dBm.
http://en.wikipedia.org/wiki/DBm
If you calculate the wattage (for example, -91 dBm as a base, -91 - 10 dBm = -101 dBm for Nexus One, -91 - 20 = -111 dBm for iPhone 4), you will see that while the Nexus drops to 1/10th of its power while held, the iPhone 4 drops to 1/100th of its power.
But it's not just power that matters in this case, its the thresholds of acceptable power levels that counts as well. Cell phones and towers can accommodate even big drops in power as long as the resulting power is enough to maintain a secure signal between the phone and the tower. If your signal strength is -51 dBm, you can drop to 1/100th of the power you had before and still have a usable signal because your phone can still make a reliable connection with that power level. The problem is that a drop to 1/100th of your original signal strength simply by holding your phone with your palm touching that lower left gap seems unusual and potentially unacceptable. Cell phone users already have to deal with many other factors that may hurt the ability of their signal to stay within the acceptable threshold, such as distance from a tower or being inside of a building, this issue only makes matters significantly worse.
The question is, is this issue acceptable or not? If other phones do not have this level of signal drop simply by holding them in a normal way, then this phone is deficient. You should be able to exchange your phone for another that does not have this deficiency.
If the phone isn't deficient, then AT&T needs to correct its coverage maps to accommodate this phone's deficiency, or create a "special" map for iPhone 4 coverage. At both my work and home, AT&T's coverage viewer says I have "Best" coverage. If I hold my phone at work or at home though, my coverage drops to 1 bar and I cannot make calls or use data. AT&T's coverage should be showing my area as "Moderate" coverage (or worse), then I wouldn't have a complaint because I could have clearly seen that AT&T has crappy coverage in my area.
Holding the iPhone 4 in your hand with the palm touching the lower left gap in the steel band is not abnormal user behavior. Although I am aware of the issue and do my best to avoid touching it, sometimes I adjust the way I hold the phone out of habit or for comfort and my palm just ends up resting against that gap and I either end up dropping the call or losing the data connection before I notice. It's disappointing because I never had this problem with my iPhone 3G, and I really like the iPhone. As an iPod Touch it is faster and better looking that the previous generation, but, for someone in a weak "5 bar" area that AT&T considers to have "Best" coverage, as a phone it is actually worse than the iPhone 3G.
Imagine if your computer completely crashed every time you hit the "t" and the "h" keys at the same time. You'd find that most of the time it wouldn't be an issue, but occasionally your fingers are so quick that you hit both keys virtually at the same time (assuming you are a fast typist); your computer crashes and you potentially lose any unsaved work. You can do two things, learn to hit the "t" key and "h" key slower, slowing down to do full taps of each, or save your work repeatedly and just accept that the computer will crash. People who type slower anyways probably wouldn't have an issue, but fast typists would find it uncomfortable and inefficient.