Radio Saver 

Epic Applications has dropped two new apps - Radio Saver and Auto Redial. Radio Saver automatically turns your device radio on and off depending on your coverage. If you are in a poor service area, the radio is turned off to save battery life. When the signal returns, it is automatically switched back on. Radio Saver works on any device running OS 4.3 and higher and is totally customizable.

Also check out Auto Redial which automatically calls back the other party when your call is dropped. Don't waste time playing phone tag after a dropped call, you can set Auto Redial to retry the call instantly or up to 10 seconds later. The app even knows if you are in a poor service area and waits to make the call. Auto Redial works on devices running OS 4.3 and higher.