As with all 3G handheld, when the 3G signal is too weak, the iPhone automatically switch to 2G. In practice, the iPhone is relatively slow to perform the transition, and sometimes when it is carried out, it has lost the signal leading to the following message:
As soon as you are one the edge of the 3G signal, then this message pops-up couple of seconds before the transition to 2G.
iPhone Atlas offers several tricks to boost the iPhone 3G signal strength, however none of them will not turn iron into gold, but can sometimes improve the reception.
The easiest way is certainly to wait for the next firmware update which should fix such parameters.
We have also tested the 3G signal performance, and as illustrated below, we could reach data transfer speed of 150 KB/s (equivalent to 2 Mbit/s ADSL):
When using the EDGE 2G network the data transfer speed dropped to 15.5 KB/s.
