The iPhone 4 doesn't use the 3G network to make phone calls. It switches to the CDMA 1xRTT for voice calls.
I'm most definitely NOT a VZW employee. If a post answered your question, please mark it as the answer.
The importance of being able to make a call while in your home cannot be understated. Rarely do I sit in one place and speak on the phone. To have a reliable signal throughout your house is of the utmost importance.
To ensure that you are receiving the optimal network conditions. I do suggest dialing *22899 from your device. If you still signal fluctuation, I do suggest resetting your network settings. To reset your network settings please follow the instructions here: Settings > General > Reset > Reset Network Settings.
If you continue to experience service issues in your home you may want to consider a network extender. With a network extender you will need to have a high speed internet connection to connect the extender to. http://vz.to/O3ZzCi
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