Why has my Iphone 4 been dropping calls recently

With every call between cell phones, it takes two to tango. It doesn't matter what your iPhone's reception level is if the reception with the other cell phone is not good. If a call between different carriers, more factors are in play. Long story short, you can't automatically assume the problem lies with your iPhone or with AT&T with a dropped call.

Try resetting network settings on your iPhone. This will also remove all saved wi-fi network settings on your iPhone which will require re-joining every wi-fi network your iPhone has access to when returning within range of such a wi-fi network.

With every call between cell phones, it takes two to tango. It doesn't matter what your iPhone's reception level is if the reception with the other cell phone is not good. If a call between different carriers, more factors are in play. Long story short, you can't automatically assume the problem lies with your iPhone or with AT&T with a dropped call.

Try resetting network settings on your iPhone. This will also remove all saved wi-fi network settings on your iPhone which will require re-joining every wi-fi network your iPhone has access to when returning within range of such a wi-fi network.