I've only dropped once using iPhone and this was when i was in a cupboard full of metal and concrete walls, (was testing how bad the deathgrip problem was) and i had another phone place a call on the same network as my iphone while i tried calling a number on my iphone using the deathgrip. it had the equal or more signal to the other phone i was using, and when the bars went down to just 1, damn it held onto that signal before it dropped. but 99% of the time i'm not going to be sitting in a cupboard
as for the test i done. i used the phone in both high and low signal area with bumper, bumper with normal grip, bumper with normal grip with a phone call, bumper with deathgrip, bumper with deathgrip and a phone call, without bumper, no bumper with normal grip, no bumpber with normal grip and a phone call, no bumper with deathgrip, no bumber with deathgrip and a phone call. i did all this variations in high signal, outside with no phones on (best situation) and with low signal, inside concrete cupboard and full of metal, with phones on making calls (worst situation) i took the most and least bars that each test gave and put them all together and figured out that my average overall realistic signal was 3.8 bars (average) then i singled out the numbers relating to bumper usage and normal grip, and got the number for both high low signal, using deathgrip, with an without calls being placed and the number i got was 3.2 bars (average) so theres only a 0.6 difference using the deathgrip (on AVERAGE, doesn't mean you wont drop a call). so most the time i should get 3 bars. if i hold it normally i will get 3-4 bars, but if i happen to touch the antenna then it goes down to 3 bars (again doesnt rule out call drops)
that was my little test. it may not be perfect but i tried to do it as best as i could with my knowledge of physics
