When I got my Samsung GS3 back in January I made sure my residence was in the coverage map which it is. I got a reliable 4g connection at the time. Several weeks later it was gone, reduced to 3g. Since I use Wi-Fi at my home I wasn't too concerned. Last week I noticed I had a solid 4g on my phone at my residence and thought that another tower had been put in or the existing one had been tweaked. Yesterday it's back to 3g. My wife's SG3 is the same. The map still shows I'm right at the middle of coverage for 4G. Trying to figure out what is wrong. Verizon changed my SIM card out with no success.