Per Verizon support I am in a marginal service area. There are three towers surrounding my home. In my driveway, 1 bar: two homes away get 3-4 bars.
So after replacing the phone (I was told by a Verizon tech that the phone initially had radio problems), I installed an extender. It seems to work fine with 3g phones. I have two which have excellent signal strength under the extender. Not so good without.
The S3 is another animal. Thinking that perhaps the extender had an antennae problem, I requested and am trying out a refurbished device. There is no difference in performance. The phone indicates it is using the extender (via screen message and #48 response). The Status program shows the strength remains at 1 bar (-105 to -110 dBm) and mobile network type indicates LTE:14. On a couple of occasions, the phone has briefly switched into EVDO mode. Suddenly the phone has 4-5 bars and a signal strength -90 dBm.
I have no idea why the phone briefly switched modes. I wish it would stay that way. The problem seems to be that the phone and/or network seems to default to LTE, whether the service is good or not. From research here and on other websites, it appears as thought the phone software (or at least other vendor's incarnations) allow(ed) a more specific selection of the network type. Under the latest Verizon software, there are only three choices: GLOBAL, LTE/CDMA and GSM/UMTS. None of them seem to allow the selection or force the use of EVDO.
BTW, with Verizon support I have done all the router setup, and connection speed testing. Any suggestions? This has been a very long and tiresome process. Verizon is this a specific limitation of the software/network/hardware on the S3 that cannot be resolved? If so, will it be addressed with the S4?
Voice calls are handled through the 1xRTT:7 network. The LTE signal has nothing to do with the strength of the voice network. The phone is picking up the closest LTE network for data not voice.