The folks at BGR got their hands on Apple's internal iPhone 4 antenna troubleshooting procedures. This is what Apple representatives are supposed to follow when you call about your reception troubles. Of course, sometimes they even give the spiel word-by-word.
As I read these guidelines provided by BGR's source, I realized they sounded familiar. Why? Because I heard points a, b, d, and e recited word-for-word when I called AppleCare to ask about the iPhone 4 antenna issue recently.
Here are the guidelines the representative I spoke with may have been following:
Keep all of the positioning statements in the BN handy – your tone when delivering this information is important.
a. The iPhone 4's wireless performance is the best we have ever shipped. Our testing shows that iPhone 4's overall antenna performance is better than iPhone 3GS.
b. Gripping almost any mobile phone in certain places will reduce its reception. This is true of the iPhone 4, the iPhone 3GS, and many other phones we have tested. It is a fact of life in the wireless world.
c. If you are experiencing this on your iPhone 3GS, avoid covering the bottom-right side with your hand.
d. If you are experiencing this on your iPhone 4, avoid covering the black strip in the lower-left corner of the metal band.
e. The use of a case or Bumper that is made out of rubber or plastic may improve wireless performance by keeping your hand from directly covering these areas.
Do not perform warranty service. Use the positioning above for any customer questions or concerns.
Don't forget YOU STILL NEED to probe and troubleshoot. If a customer calls about their reception while the phone is sitting on a table (not being held) it is not the metal band.
ONLY escalate if the issue exists when the phone is not held AND you cannot resolve it.
We ARE NOT appeasing customers with free bumpers – DON'T promise a free bumper to customers
source : http://gizmodo.com/5575779/apples-internal-iphone-4-antenna-troubleshooting-guidelines-leak