A bit of drama popped up with the introduction of the iPhone 4. Users complained that if they held the phone in a certain way, the phone’s signal bars would drop dramatically. Apple responded by announcing that they were working on the formula on how bars are calculated.
It’s the popularity of the iPhone 4 that has brought the issue of how you hold the phone effects signal quality to the forefront. However, the potential to lose signal occurs in pretty much any cell phone if you cover the internal antenna with your hand or your head gets between the phone and cell tower. So, this is not a new issue. I’m guessing that Apple’s announcement to change the signal bar calculation means that the signal drop should not be as dramatic as reported and that Apple feels that the actual problem is not the iPhone design (Where they placed the internal antenna).
Unfortunately there is no standard for calculating signal bars in relation to actual received signal strength reading. Is Apple or AT&T any different from other carriers and manufacturers in the way they calculate signal bars? From our personal experience and testing, the major carriers and phone manufactures are all over the board in calculating signal bars as compared to the device received signal strength. The formulas are proprietary so there little that can be done to evaluate each. We have even seen cases where 2 phones on the same network, show different number of signal bars.
The most accurate way to determine your signal strength is to put your device into test mode and get a signal reading (in dbm). A BlackBerry’s signal reading can be found in Options > Status. Many GSM devices, including the iPhone 4, do not allow you to access test mode or any signal reading.
Here’s a good article with lots of contributions from the Wall Street Journal blogger on the issue.